Mosquito-borne diseases or mosquito-borne illnesses are diseases caused by bacteria, viruses or parasites transmitted by mosquitoes . Nearly 700 million people contract mosquito-borne illnesses each year, resulting in more than a million deaths.
135-407: Dengue fever is a mosquito-borne disease caused by dengue virus , prevalent in tropical and subtropical areas. It is frequently asymptomatic ; if symptoms appear they typically begin 3 to 14 days after infection. These may include a high fever , headache , vomiting , muscle and joint pains , and a characteristic skin itching and skin rash . Recovery generally takes two to seven days. In
270-424: A mosquito net . Dengue infection's therapeutic management is simple, cost effective and successful in saving lives by adequately performing timely institutionalized interventions. Treatment options are restricted, while no effective antiviral drugs for this infection have been accessible to date. Patients in the early phase of the dengue virus may recover without hospitalization. However, ongoing clinical research
405-407: A 1-liter habitat per day while people there try to have their water in much larger volume there come at-home mosquito habitats, they don't emerge at once but gradually throughout the day. At best spraying will kill all live insects at the time, not the newly emerges. Second, people are wary, think twice on any introduction of poison into their own home. Therefore, for the prevention to be effective it
540-407: A blood meal from the infected host then propagates the virus in the cells lining its gut. Over the next few days, the virus spreads to other tissues including the mosquito's salivary glands and is released into its saliva. Next time the mosquito feeds, the infectious saliva will be injected into the bloodstream of its victim, thus spreading the disease. The virus seems to have no detrimental effect on
675-849: A community is most likely to employ. Leading to a targeted prevention method that has a higher chance of success in that particular community. Community outreach and education includes engaging community health workers and local healthcare providers, local schools and community organizations to educate the public on mosquito vector control and disease prevention. Numerous drugs have been used to treat yellow fever disease with minimal satisfaction to date. Patients with multisystem organ involvement will require critical care support such as possible hemodialysis or mechanical ventilation . Rest, fluids, and acetaminophen are also known to relieve milder symptoms of fever and muscle pain. Due to hemorrhagic complications, aspirin should be avoided. Infected individuals should avoid mosquito exposure by staying indoors or using
810-500: A diagnosis of dengue. During the first few days of infection, enzyme-linked immunosorbent assay ( ELISA ) can be used to detect the NS1 antigen ; however this antigen is produced by all flaviviruses. Four or five days into the infection, it is possible to reliably detect anti-dengue IgM antibodies, but this does not determine the serotype. Nucleic acid amplification tests provide the most reliable method of diagnosis. As of July 2024, there
945-591: A few days as the fever subsides. Leakage of plasma from the capillaries results in extreme low blood pressure and hypovolemic shock ; Patients with severe plasma leakage may have fluid accumulation in the lungs or abdomen , insufficient protein in the blood , or thickening of the blood . Severe dengue is a medical emergency which can cause damage to organs, leading to multiple organ failure and death. Mild cases of dengue fever can easily be confused with several common diseases including Influenza , measles , chikungunya , and zika . Dengue, chikungunya and zika share
1080-449: A first approximation, the shape can be considered similar to oblate spheroids , with a semiaxis ratio of 2 to 8. This approximation can be used to model the hydrodynamic and optical properties of a population, as well as to restore the geometric parameters of individual measured platelets by flow cytometry . More accurate biophysical models of platelet surface morphology that model its shape from first principles, make it possible to obtain
1215-404: A laboratory test of body fluids, such as urine or saliva, or by blood test. Laboratory blood tests can identify evidence of chikungunya or other similar viruses such as dengue and Zika. Blood test may confirm the presence of IgM and IgG anti-chikungunya antibodies. IgM antibodies are highest 3 to 5 weeks after the beginning of symptoms and will continue be present for about 2 months. There
1350-476: A more realistic platelet geometry in a calm and activated state. The fundamental function of platelets is to clump together to stop acute bleeding. This process is complex, as more than 193 proteins and 301 interactions are involved in platelet dynamics. Despite much overlap, platelet function can be modeled in three steps: Thrombus formation on an intact endothelium is prevented by nitric oxide , prostacyclin , and CD39 . Endothelial cells attach to
1485-701: A multitude of microthrombi of similar composition to that in physiological immunothrombosis — fibrin, platelets, neutrophils and NETs. Platelets rapidly deploy to sites of injury or infection, and potentially modulate inflammatory processes by interacting with leukocytes and secreting cytokines , chemokines , and other inflammatory mediators. Platelets also secrete platelet-derived growth factor (PDGF). Platelets modulate neutrophils by forming platelet-leukocyte aggregates (PLAs). These formations induce upregulated production of αmβ2 ( Mac-1 ) integrin in neutrophils. Interaction with PLAs also induces degranulation and increased phagocytosis in neutrophils. Platelets are
SECTION 10
#17327808366131620-463: A pathologic and excessive quantity of clot. In a third context it is used to contrast the result from the process: thrombus is the result, thrombosis is the process. Structurally the platelet can be divided into four zones, from peripheral to innermost: Circulating inactivated platelets are biconvex discoid (lens-shaped) structures, 2–3 μm in greatest diameter. Activated platelets have cell membrane projections covering their surface. In
1755-425: A physical examination and ask about medical history as well as any travel history. Be ready to give details on any international trips, including the dates you were traveling, the countries you visited and any contact you had with mosquitoes. Diagnosing dengue fever can be difficult, as its symptoms often overlap with many other diseases such as malaria and typhoid fever . Laboratory tests can detect evidence of
1890-501: A protein coat. Once inside the host's body, the virus will attach itself to a cell's surface through receptor-mediated endocytosis. This essentially means that the proteins and DNA material of the virus are ingested into the host cell. The viral RNA material will undergo several changes and processes inside the host's cell so that it can release more viral RNA that can then be replicated and assembled to infect neighboring host cells. Mosquito-borne flaviviruses also encode viral antagonists to
2025-676: A receptor for IgG's constant fragment (Fc). When activated and bound to IgG opsonised bacteria, platelets release reactive oxygen species (ROS), antimicrobial peptides, defensins , kinocidins and proteases , killing the bacteria directly. Platelets also secrete proinflammatory and procoagulant mediators such as inorganic polyphosphates or platelet factor 4 (PF4), connecting innate and adaptive immune responses. Spontaneous and excessive bleeding can occur because of platelet disorders. This bleeding can be caused by deficient numbers of platelets, dysfunctional platelets, or platelet densities over 1 million/microliter. (The excessive numbers create
2160-777: A relative von Willebrand factor deficiency due to sequestration.) Bleeding due to a platelet disorder or a coagulation factor disorder can be distinguished by the characteristics and location of the bleeding. Platelet bleeding involves bleeding from a cut is prompt and excessive, but can be controlled by pressure; spontaneous bleeding into the skin which causes a purplish stain named by its size: petechiae , purpura , ecchymoses ; bleeding into mucous membranes causing bleeding gums, nose bleed, and gastrointestinal bleeding; menorrhagia; and intraretinal and intracranial bleeding. Excessive numbers of platelets, and/or normal platelets responding to abnormal vessel walls, can result in venous thrombosis and arterial thrombosis . The symptoms depend on
2295-494: A result of turning on the GPIIb/IIIa receptor, allowing these receptors to bind with vWF or fibrinogen . Each platelet has around 60,000 of these receptors. When any one or more of at least nine different platelet surface receptors are turned on during activation, intraplatelet signaling pathways cause existing GpIIb/IIIa receptors to change shape — curled to straight — and thus become capable of binding. Since fibrinogen
2430-630: A small proportion it is life-threatening. The incubation period (time between exposure and onset of symptoms) ranges from 3 to 14 days, but most often it is 4 to 7 days. The characteristic symptoms of mild dengue are sudden-onset fever, headache (typically located behind the eyes), muscle and joint pains, nausea, vomiting, swollen glands and a rash. If this progresses to severe dengue the symptoms are severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, fatigue, restlessness, blood in vomit or stool, extreme thirst, pale and cold skin, and feelings of weakness. The course of infection
2565-405: A small proportion of cases, the disease develops into severe dengue (previously known as dengue hemorrhagic fever or dengue shock syndrome) with bleeding , low levels of blood platelets , blood plasma leakage, and dangerously low blood pressure . Dengue virus has four confirmed serotypes ; infection with one type usually gives lifelong immunity to that type, but only short-term immunity to
2700-473: A ten fold increase between 2010 and 2019 (from 500,000 to 5 million recorded cases). This increase is tied closely to the increasing range of Aedes mosquitoes, which is attributed to a combination of urbanization , population growth, and an increasingly warm climate . In endemic areas, dengue infections peak when rainfall is optimal for mosquito breeding. In October 2023, the first confirmed symptomatic case of locally acquired dengue (i.e. not while travelling) in
2835-447: Is 0.8–2.5%, and with adequate treatment this is less than 1%. However, those who develop significantly low blood pressure may have a fatality rate of up to 26%. The risk of death among children less than five years old is four times greater than among those over the age of 10. Elderly people are also at higher risk of a poor outcome. As of March 2023, dengue is endemic in more than 100 countries with cases reported in every continent with
SECTION 20
#17327808366132970-920: Is a leading cause of premature mortality, particularly in children under the age of five, with an estimated 207 million cases and more than half a million deaths in 2012, according to the World Malaria Report 2013 published by the World Health Organization (WHO). The death toll increased to one million as of 2018 according to the American Mosquito Control Association. In January 2024, a publication by an Australian research group demonstrated significant genetic similarity between Mycobacterium ulcerans in humans and possums, compared to PCR screening of M. ulcerans from trapped Aedes notoscriptus mosquitoes, and concluded that Mycobacterium ulcerans ,
3105-456: Is a live attenuated vaccine containing the four serotypes of dengue virus, administered subcutaneously as two doses three months apart. The World Health Organization 's International Classification of Diseases divides dengue fever into two classes: uncomplicated and severe. Severe dengue is defined as that associated with severe bleeding, severe organ dysfunction, or severe plasma leakage. Severe dengue can develop suddenly, sometimes after
3240-501: Is a re-emergence of mosquito vectored viruses (arthropod-borne viruses) called arboviruses carried by the Aedes aegypti mosquito. Examples are the Zika virus, chikungunya virus, yellow fever and dengue fever. The re-emergence of the viruses has been at a faster rate, and over a wider geographic area, than in the past. The rapid re-emergence is due to expanding global transportation networks,
3375-449: Is a rod-like protein with nodules on either end capable of binding GPIIb/IIIa, activated platelets with exposed GPIIb/IIIa can bind fibrinogen to aggregate. GPIIb/IIIa may also further anchor the platelets to subendothelial vWF for additional structural stabilisation. Classically it was thought that this was the only mechanism involved in aggregation, but three other mechanisms have been identified which can initiate aggregation, depending on
3510-585: Is a system for analysing platelet function in which citrated whole blood is aspirated through a disposable cartridge containing an aperture within a membrane coated with either collagen and epinephrine or collagen and ADP. These agonists induce platelet adhesion, activation and aggregation, leading to rapid occlusion of the aperture and cessation of blood flow termed the closure time (CT). An elevated CT with EPI and collagen can indicate intrinsic defects such as von Willebrand disease , uremia , or circulating platelet inhibitors. A follow-up test involving collagen and ADP
3645-428: Is an RNA virus of the family Flaviviridae ; genus Flavivirus . Other members of the same genus include yellow fever virus , West Nile virus , and Zika virus . Dengue virus genome (genetic material) contains about 11,000 nucleotide bases , which code for the three structural protein molecules (C, prM and E) that form the virus particle and seven other protein molecules that are required for replication of
3780-444: Is another prevention method widely used to control mosquito vectors. To help control the Aedes aegypti mosquito, homes are sprayed indoors with residual insecticide applications. Indoor residual spraying (IRS) reduces the female mosquito population and mitigates the risk of dengue virus transmission. Indoor residual spraying is completed usually once or twice a year. Mosquitoes rest on walls and ceilings after feeding and are killed by
3915-404: Is at higher risk of miscarriage , low birth weight , and premature birth . Children and older individuals are at a risk of developing complications from dengue fever compared to other age groups; young children typically suffer from more intense symptoms. Concurrent infections with tropical diseases like Zika virus can worsen symptoms and make recovery more challenging. Dengue virus (DENV)
4050-457: Is called severe dengue (formerly called dengue hemorrhagic fever or dengue shock syndrome ). Severe dengue can lead to shock, internal bleeding, organ failure and even death. Warning signs include severe stomach pain, vomiting, difficulty breathing, and blood in the nose, gums, vomit or stools. During this period, there is leakage of plasma from the blood vessels, together with a reduction in platelets . This may result in fluid accumulation in
4185-480: Is caused by infection through viruses of the family Flaviviridae. The illness is most commonly transmitted by Aedes aegypti mosquitoes in tropical and subtropical regions. Dengue virus has four different serotypes, each of which are antigenically related but have limited cross-immunity to reinfection. Although dengue fever has a global incidence of 50–100 million cases, only several hundreds of thousands of these cases are life-threatening. The geographic prevalence of
Dengue fever - Misplaced Pages Continue
4320-438: Is classified as a neglected tropical disease . During 2023, more than 5 million infections were reported, with more than 5,000 dengue-related deaths. As most cases are asymptomatic or mild, the actual numbers of dengue cases and deaths are under-reported. Typically, people infected with dengue virus are asymptomatic (80%) or have only mild symptoms such as an uncomplicated fever. Others have more severe illness (5%), and in
4455-423: Is divided into three phases: febrile, critical, and recovery. The febrile phase involves high fever (40 °C/104 °F), and is associated with generalized pain and a headache; this usually lasts two to seven days. There may also be nausea, vomiting, a rash, and pains in the muscle and joints. Most people recover within a week or so. In about 5% of cases, symptoms worsen and can become life-threatening. This
4590-420: Is due to the fact that most viruses and bacteria caused by mosquitos are highly mutatable. The National Institute of Allergy and Infectious Disease (NIAID) began Phase 1 clinical trials of a new vaccine that would be nearly universal in protecting against the majority of mosquito-borne diseases. The arboviruses have expanded their geographic range and infected populations that had no recent community knowledge of
4725-410: Is endemic have only one serotype of the virus in circulation. The disease is said to be hyperendemic in areas where more than one serotype is circulating; this increases the risk of severe disease on a second or subsequent infection. Infections are most commonly acquired in urban environments where the virus is primarily transmitted by the mosquito species Aedes aegypti . This species has adapted to
4860-792: Is given subcutaneously as three doses at six month intervals. Qdenga (formerly TAK-003) completed clinical trials in 2022 and was approved for use in the European Union in December 2022; it has been approved by a number of other countries including Indonesia and Brazil, and has been recommended by the SAGE committee of the World Health Organization. It is indicated for the prevention of dengue disease in individuals four years of age and older, and can be administered to people who have not been previously infected with dengue. It
4995-409: Is high population density, poor sanitation, and standing water where mosquitoes can breed. It can be mitigated by taking steps to avoid bites such as by wearing clothing that fully covers the skin, using mosquito netting while resting, and/or the application of insect repellent ( DEET being the most effective). Chronic diseases – such as asthma, sickle cell anemia, and diabetes mellitus – increase
5130-1182: Is in the works to find specific anti-dengue drugs. Dengue fever occurs via Aedes aegypti mosquito (it acts as a vector). Zika virus vaccine clinical trials are to be conducted and established. There are efforts being put toward advancing antiviral therapeutics against zika virus for swift control. Present day Zika virus treatment is symptomatic through antipyretics and analgesics . Currently there are no publications regarding viral drug screening. Nevertheless, therapeutics for this infection have been used. There are no treatment modalities for acute and chronic chikungunya that currently exist. Most treatment plans use supportive and symptomatic care like analgesics for pain and anti-inflammatories for inflammation caused by arthritis . In acute stages of this virus, rest, antipyretics and analgesics are used to subside symptoms. Most use non-steroidal anti-inflammatory drugs (NSAIDs). In some cases, joint pain may resolve from treatment but stiffness remains. The sterile insect technique (SIT) uses irradiation to sterilize insect pests before releasing them in large numbers to mate with wild females. Since they do not produce any offspring,
5265-444: Is initiated either by immune cells by activating their pattern recognition receptors (PRRs), or by platelet-bacterial binding. Platelets can bind to bacteria either directly through thrombocytic PRRs and bacterial surface proteins, or via plasma proteins that bind both to platelets and bacteria. Monocytes respond to bacterial pathogen-associated molecular patterns (PAMPs), or damage-associated molecular patterns (DAMPs) by activating
5400-436: Is mixed with saline and a platelet agonist in a single-use cuvette with two pairs of electrodes. The increase in impedance between the electrodes as platelets aggregate onto them, is measured and visualized as a curve. In light transmission aggregometry (LTA), platelet-rich plasma is placed between a light source and a photocell . Unaggregated plasma allows relatively little light to pass through. After adding an agonist,
5535-759: Is mostly characterized by high fever, headaches, joint pain, and rash. However, more severe instances can lead to hemorrhagic fever, internal bleeding, and breathing difficulty, which can be fatal. People infected with this virus can develop sudden onset fever along with debilitating joint and muscle pain, rash, headache, nausea, and fatigue. Symptoms can last a few days or be prolonged to weeks and months. Although patients can recover completely, there have been cases in which joint pain has persisted for several months and can extend beyond that for years. Other people can develop heart complications, eye problems, and even neurological complications. Mosquitoes carrying such arboviruses stay healthy because their immune systems recognizes
Dengue fever - Misplaced Pages Continue
5670-410: Is necessary to have mosquito-to-be larvae and pupae in people's houses killed without contaminating their water such as to have them suffocated. Only female mosquito bite on only warm blooded animals, they have capability to identify and target their hosts from 1–3 miles away in real time proportioning to 1500 miles in human distance. Even us, we only can identify miles far targets through vision, by
5805-485: Is no specific antiviral treatment available for dengue fever. Most cases of dengue fever have mild symptoms, and recovery takes place in a few days. No treatment is required for these cases. Acetaminophen (Paracetamol, Tylenol ) may be used to relieve mild fever or pain. Other common pain relievers, including aspirin , ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve) should be avoided as they can increase
5940-455: Is not fully understood. It appears that ADE occurs when the antibodies generated during an immune response recognize and bind to a pathogen, but they fail to neutralize it. Instead, the antibody-virus complex has an enhanced ability to bind to the Fcγ receptors of the target immune cells, enabling the virus to infect the cell and reproduce itself. When a dengue virus carrying mosquito bites a person,
6075-513: Is not thought to be effective. Reducing open collections of water through environmental modification is the preferred method of control, given the concerns of negative health effects from insecticides and greater logistical difficulties with control agents. Ideally, mosquito control would be a community activity, e.g. when all members of a community clear blocked gutters and street drains and keep their yards free of containers with standing water. If residences have direct water connections this eliminates
6210-503: Is rare. Most people infected with the West Nile virus usually do not develop symptoms. However, some individuals can develop cases of severe fatigue, weakness, headaches, body aches, joint and muscle pain, vomiting, diarrhea, and rash, which can last for weeks or months. More serious symptoms have a greater risk of appearing in people over 60 years of age, or those with cancer, diabetes, hypertension, and kidney disease. Dengue fever
6345-535: Is suitable for adults, adolescents and children from four years of age. The earliest descriptions of a dengue outbreak date from 1779; its viral cause and spread were understood by the early 20th century. Already endemic in more than one hundred countries, dengue is spreading from tropical and subtropical regions to the Iberian Peninsula and the southern states of the US, partly attributed to climate change. It
6480-597: Is supportive and includes giving fluid either by mouth or intravenously . Dengue is spread by several species of female mosquitoes of the Aedes genus , principally Aedes aegypti . Infection can be prevented by mosquito elimination and the prevention of bites. Two types of dengue vaccine have been approved and are commercially available. Dengvaxia became available in 2016 but it is only recommended to prevent re-infection in individuals who have been previously infected. The second vaccine, Qdenga, became available in 2022 and
6615-442: Is the chemical motor that pulls the invaginated OCS out of the interior of the platelet, like turning pants pockets inside out, creating the dendrites. This process is similar to the mechanism of contraction in a muscle cell . The entire OCS thus becomes indistinguishable from the initial platelet membrane as it forms the "fried egg". This dramatic increase in surface area comes about with neither stretching nor adding phospholipids to
6750-450: Is used to indicate if the abnormal CT with collagen and EPI was caused by the effects of acetyl sulfosalicylic acid (aspirin) or medications containing inhibitors. The PFA-100 is highly sensitive to von Willebrand disease, but is only moderately sensitive to defects in platelet function. Low platelet concentration is called thrombocytopenia , and is due to either decreased production or increased destruction. Elevated platelet concentration
6885-520: The PI3K/Akt pathway during a first wave of aggregation, leading to thrombin generation and PAR‐1 activation, which evokes a second wave of aggregation. Platelet activation begins seconds after adhesion occurs. It is triggered when collagen from the subendothelium binds with its receptors ( GPVI receptor and integrin α2β1) on the platelet. GPVI is associated with the Fc receptor gamma chain and leads via
SECTION 50
#17327808366137020-458: The chest and abdominal cavity as well as depletion of fluid from the circulation and decreased blood supply to vital organs . The recovery phase usually lasts two to three days. The improvement is often striking, and can be accompanied with severe itching and a slow heart rate . Complications following severe dengue include fatigue, somnolence, headache, concentration impairment and memory impairment. A pregnant woman who develops dengue
7155-515: The coagulation cascade , with resultant fibrin deposition and linking (secondary hemostasis). These processes may overlap: the spectrum is from a predominantly platelet plug, or "white clot" to a predominantly fibrin, or "red clot" or the more typical mixture. Berridge adds retraction and platelet inhibition as fourth and fifth steps, while others would add a sixth step, wound repair . Platelets participate in both innate and adaptive intravascular immune responses. In addition to facilitating
7290-419: The megakaryocytes of the bone marrow or lung, which then enter the circulation. Platelets are found only in mammals, whereas in other vertebrates (e.g. birds , amphibians ), thrombocytes circulate as intact mononuclear cells . One major function of platelets is to contribute to hemostasis : the process of stopping bleeding at the site of interrupted endothelium . They gather at the site and, unless
7425-404: The virions as foreign particles and "chop off" the virus' genetic coding, rendering it inert. Human infection with a mosquito-borne virus occurs when a female mosquito bites someone while its immune system is still in the process of destroying the virus's harmful coding. It is not completely known how mosquitoes handle eukaryotic parasites to carry them without being harmed. Data has shown that
7560-458: The 15th to 19th centuries due to the slave trade and consequent expansion of international trading. There have been descriptions of epidemics of dengue-like illness in the 17th century, and it is likely that epidemics in Jakarta , Cairo , and Philadelphia during the 18th century were caused by dengue. It is assumed that dengue was constantly present in many tropical urban centres throughout
7695-481: The 19th and early 20th centuries, even though significant outbreaks were infrequent. The marked spread of dengue during and after the Second World War has been attributed partly to disruption caused by the war, and partly to subsequent urbanisation in south-east Asia. As novel serotypes were introduced to regions already endemic with dengue, outbreaks of severe disease followed. The severe hemorrhagic form of
7830-759: The 21st century, as the mosquito vector continues to expand its range. This is attributed partly to continuing urbanisation, and partly to the impact of a warmer climate. Mosquito-borne disease Diseases transmitted by mosquitoes include malaria , dengue , West Nile virus , chikungunya , yellow fever , filariasis , tularemia , dirofilariasis , Japanese encephalitis , Saint Louis encephalitis , Western equine encephalitis , Eastern equine encephalitis , Venezuelan equine encephalitis , Ross River fever , Barmah Forest fever , La Crosse encephalitis , and Zika fever , as well as newly detected Keystone virus and Rift Valley fever . In January 2024, an Australian research group proved that Mycobacterium ulcerans ,
7965-767: The NETosis and phagocytosis. Platelets also participate in chronic inflammatory disease, such as synovitis or rheumatoid arthritis . Platelets are activated by collagen receptor glycoprotein IV (GPVI). Proinflammatory platelet microvesicles trigger constant cytokine secretion from neighboring fibroblast-like synoviocytes , most prominently Il-6 and Il-8 . Inflammatory damage to the surrounding extracellular matrix continuously reveals more collagen, maintaining microvesicle production. Activated platelets are able to participate in adaptive immunity , interacting with antibodies . They are able to specifically bind IgG through FcγRIIA ,
8100-599: The US was identified in California. The disease infects all races, sexes, and ages equally. In endemic areas, the infection is most commonly seen in children who then acquire a lifelong partial immunity. The first historical record of a case of probable dengue fever is in a Chinese medical encyclopedia from the Jin dynasty (266–420) which referred to a "water poison" associated with flying insects. The principal mosquito vector of dengue, Aedes aegypti , spread out of Africa in
8235-477: The United States where they cause disease in humans, horses, and some bird species. Because of the high mortality rate, EEE and WEE are regarded as two of the most serious mosquito-borne diseases in the United States. Symptoms range from mild flu-like illness to encephalitis, coma, and death. Viruses carried by arthropods such as mosquitoes or ticks are known collectively as arboviruses . West Nile virus
SECTION 60
#17327808366138370-436: The activation of a tyrosine kinase cascade finally to the activation of PLC-gamma2 ( PLCG2 ) and more calcium release. Tissue factor also binds to factor VII in the blood, which initiates the extrinsic coagulation cascade to increase thrombin production. Thrombin is a potent platelet activator, acting through Gq and G12. These are G protein-coupled receptors and they turn on calcium-mediated signaling pathways within
8505-481: The authority achieve zero yellow fever and zero malaria status where patients were aggressively treat in off-site facilities. By setting up rural health canters for detection thus come with early patient (harmful) treatments, faster to become harmless, to lessen the number of infected mosquitoes, some communities could achieve near zero-malaria infection ratio while others in larger general region got outbroken. The use of insecticide treated mosquito nets (ITNs) are at
8640-426: The bacteria. Although thrombosis, blood coagulation in intact blood vessels, is usually viewed as a pathological immune response, leading to obturation of lumen of blood vessel and subsequent hypoxic tissue damage, in some cases, directed thrombosis, called immunothrombosis, can locally control the spread of an infection. The thrombosis is directed in concordance of platelets, neutrophils and monocytes . The process
8775-445: The binding of these coagulation factors. In addition to interacting with vWF and fibrin, platelets interact with thrombin, Factors X, Va, VIIa, XI, IX, and prothrombin to complete formation via the coagulation cascade. Human platelets do not express tissue factor . Rat platelets do express tissue factor protein and carry both tissue factor pre-mRNA and mature mRNA. Platelet aggregation begins minutes after activation, and occurs as
8910-470: The blood of non-mammalian vertebrates: they are the functional equivalent of platelets, but circulate as intact cells rather than cytoplasmic fragments of bone marrow megakaryocytes. In some contexts, the word thrombus is used interchangeably with the word clot , regardless of its composition (white, red, or mixed). In other contexts it is used to contrast a normal from an abnormal clot: thrombus arises from physiologic hemostasis, thrombosis arises from
9045-425: The blood pressure becomes so low that it cannot supply sufficient blood to vital organs. The spread of the virus to the bone marrow leads to reduced numbers of platelets, which are necessary for effective blood clotting; this increases the risk of bleeding, the other major complication of dengue fever. The principal risk for infection with dengue is the bite of an infected mosquito. This is more probable in areas where
9180-532: The body via the bloodstream. The spread of this infection cycle then continues when other mosquitoes bite the same individual. The result will cause that mosquito to ingest the parasite and allow it to transmit the Malaria disease into another person through the same mode of bite injection. Flaviviridae viruses transmissible via vectors like mosquitoes include West Nile virus and yellow fever virus, which are single stranded, positive-sense RNA viruses enveloped in
9315-558: The causative pathogen of Buruli ulcer is transmitted by mosquitoes. This is the first described mosquito-borne transmission of a bacterial disease. There is no evidence as of April 2020 that COVID-19 can be transmitted by mosquitoes, and it is extremely unlikely this could occur. The female mosquito of the genus Anopheles may carry the malaria parasite . Four different species of protozoa cause malaria: Plasmodium falciparum , Plasmodium malariae , Plasmodium ovale and Plasmodium vivax (see Plasmodium ). Worldwide, malaria
9450-411: The causative pathogen of Buruli ulcer , is transmitted by mosquitos. Botflies are known to parasitize humans or other mammalians, causing myiasis , and to use mosquitoes as intermediate vector agents to deposit eggs on a host. The human botfly Dermatobia hominis attaches its eggs to the underside of a mosquito, and when the mosquito takes a blood meal from a human or an animal, the body heat of
9585-548: The cerebrospinal fluid surrounding your brain and spinal cord. The fluid sample may show an elevated white cell count and antibodies to the West Nile virus if you were exposed. In some cases, an electroencephalography (EEG) or magnetic resonance imaging (MRI) scan can help detect brain inflammation. A Zika virus infection might be suspected if symptoms are present and an individual has traveled to an area with known Zika virus transmission. Zika virus can only be confirmed by
9720-484: The clotting process, platelets contain cytokines and growth factors which can promote wound healing and regeneration of damaged tissues. The term thrombocyte (clot cell) came into use in the early 1900s and is sometimes used as a synonym for platelet; but not generally in the scientific literature, except as a root word for other terms related to platelets (e.g. thrombocytopenia meaning low platelets). The term thrombocytes are proper for mononuclear cells found in
9855-429: The connection between thrombocytes and immune cells. The platelet cell membrane has receptors for collagen. Following rupture of the blood vessel wall, platelets are exposed and adhere to the collagen in the surrounding tissue. As hemostasis is a basic function of thrombocytes in mammals, it also has its uses in possible infection confinement. In case of injury, platelets, together with the coagulation cascade, provide
9990-489: The coupled Gs protein to increase adenylate cyclase activity and increases the production of cAMP, further promoting the efflux of calcium and reducing intracellular calcium availability for platelet activation. ADP on the other hand binds to purinergic receptors on the platelet surface. Since the thrombocytic purinergic receptor P2Y12 is coupled to Gi proteins, ADP reduces platelet adenylate cyclase activity and cAMP production, leading to accumulation of calcium inside
10125-1132: The dengue virus has evolved rapidly over time, posing challenges to both government and public health officials. Malaria is caused by a protozoan called Plasmodium falciparum . P. falciparum parasites are transmitted mainly by the Anopheles gambiae complex in rural Africa. In just this area, P. falciparum infections comprise an estimated 200 million clinical cases and 1 million annual deaths. 75% of individuals affected in this region are children. As with dengue, changing environmental conditions have led to novel disease characteristics. Due to increased illness severity, treatment complications, and mortality rates, many public health officials concede that malaria patterns are rapidly transforming in Africa. Scarcity of health services, rising instances of drug resistance, and changing vector migration patterns are factors that public health officials believe contribute to malaria's dissemination. Climate heavily affects mosquito vectors of malaria and dengue. Climate patterns influence
10260-413: The dengue viruses, however the results often come back too late to assist in directing treatment. Medical testing can confirm the presence of West Nile fever or a West Nile-related illness, such as meningitis or encephalitis. If infected, a blood test may show a rising level of antibodies to the West Nile virus. A lumbar puncture (spinal tap) is the most common way to diagnose meningitis, by analyzing
10395-436: The disease can be examined by the spread of Aedes aegypti . Over the last twenty years, there has been a geographic spread of the disease. Dengue incidence rates have risen sharply within urban areas which have recently become endemic hot spots for the disease. The recent spread of Dengue can also be attributed to rapid population growth, increased coagulation in urban areas, and global travel. Without sufficient vector control,
10530-438: The disease include A. albopictus , A. polynesiensis and A. scutellaris . Humans are the primary host of the virus, but it also circulates in nonhuman primates , and can infect other mammals. An infection can be acquired via a single bite. For 2 to 10 days after becoming newly infected, a person's bloodstream will contain a high level of virus particles (the viremic period). A female mosquito that takes
10665-454: The disease is endemic, especially where there is high population density, poor sanitation, and standing water where mosquitoes can breed. It can be mitigated by taking steps to avoid bites such as by wearing clothing that fully covers the skin, using mosquito netting while resting, and/or the application of insect repellent (DEET being the most effective); it is also advisable to treat clothing, nets and tents with 0.5% permethrin . Protection of
10800-579: The disease itself. The risk of complications from the vaccine are greater for individuals over 60 years of age. In addition, the vaccine is not usually administered to babies under nine months of age, pregnant women, people with allergies to egg protein, and individuals living with AIDS/HIV . The World Health Organization (WHO) reports that 105 million people have been vaccinated for yellow fever in West Africa from 2000 to 2015. To date, there are relatively few vaccines against mosquito-borne diseases, this
10935-662: The disease was first reported in the Philippines in 1953; by the 1970s, it had become recognised as a major cause of child mortality in Southeast Asia. In Central and South America, the Aedes mosquito had been eradicated in the 1950s; however the eradication program was discontinued in the 1970s and the disease re-established itself in the region during the 1980s, becoming hyperendemic and causing significant epidemics. Dengue has continued to increase in prevalence during
11070-469: The disease with such precision. Platelet Platelets or thrombocytes (from Ancient Greek θρόμβος ( thrómbos ) 'clot' and κύτος ( kútos ) 'cell') are a blood component whose function (along with the coagulation factors ) is to react to bleeding from blood vessel injury by clumping, thereby initiating a blood clot . Platelets have no cell nucleus ; they are fragments of cytoplasm derived from
11205-502: The diseases carried by the Aedes aegypti mosquito. Education and community awareness campaigns are necessary for prevention to be effective. Communities are educated on how the disease is spread, how they can protect themselves from infection and the symptoms of infection. Community health education programs can identify and address the social/economic and cultural issues that can hinder preventative measures. Community outreach and education programs can identify which preventative measures
11340-571: The exception of Antarctica. The Americas, Southeast Asia and the Western Pacific regions are the most seriously affected. It is difficult to estimate the full extent of the disease, as many cases are mild and not correctly diagnosed. WHO currently estimates that 3.9 billion people are at risk of dengue infection. In 2013, it was estimated that 390 million dengue infections occur every year, with 500,000 of these developing severe symptoms and 25,000 deaths. Generally, areas where dengue
11475-483: The exterior. Bound and activated platelets degranulate to release platelet chemotactic agents to attract more platelets to the site of endothelial injury. Granule characteristics: As shown by flow cytometry and electron microscopy , the most sensitive sign of activation, when exposed to platelets using ADP, are morphological changes. Mitochondrial hyperpolarization is a key event in initiating morphology changes. Intraplatelet calcium concentration increases, stimulating
11610-455: The extrinsic pathway of coagulation. Neutrophils facilitate the blood coagulation by NETosis , while platelets facilitate neutrophils' NETosis. NETs bind tissue factor, binding the coagulation centers to the location of infection. They also activate the intrinsic coagulation pathway by providing its negatively charged surface to the factor XII. Other neutrophil secretions, such as proteolytic enzymes which cleave coagulation inhibitors, also bolster
11745-552: The first line of defense by forming a blood clot. Hemostasis and host defense were thus intertwined in evolution. For example, in the Atlantic horseshoe crab (estimated to be over 400 million years old), the only blood cell type, the amebocyte , facilitates both the hemostatic function and the encapsulation and phagocytosis of pathogens by means of exocytosis of intracellular granules containing bactericidal defense molecules. Blood clotting supports immune function by trapping
11880-517: The forefront of preventing mosquito bites that cause malaria. The prevalence of ITNs in sub-Saharan Africa has grown from 3% of households to 50% of households from 2000 to 2010 with over 254 million insecticide treated nets distributed throughout sub-Saharan Africa for use against the mosquito vectors Anopheles gambiae and Anopheles funestus which carry malaria. Because the Anopheles gambiae feeds indoors (endophagic) and rests indoors after feeding (endophilic), insecticide treated nets (ITNs) interrupt
12015-568: The home can be achieved with door and window screens, by using air conditioning, and by regularly emptying and cleaning all receptacles both indoors and outdoors which may accumulate water (such as buckets, planters, pools or trashcans). The primary method of controlling A. aegypti is by eliminating its habitats . This is done by eliminating open sources of water, or if this is not possible, by adding insecticides or biological control agents to these areas. Generalized spraying with organophosphate or pyrethroid insecticides, while sometimes done,
12150-462: The immune reaction it provokes. When a mosquito bites a human, it injects saliva and anti-coagulants . With the initial bite to an individual, there is no reaction, but with subsequent bites, the body's immune system develops antibodies . The bites become inflamed and itchy within 24 hours. This is the usual reaction in young children. With more bites, the sensitivity of the human immune system increases, and an itchy red hive appears in minutes where
12285-467: The immune response has broken capillary blood vessels and fluid has collected under the skin. This type of reaction is common in older children and adults. Some adults can become desensitized to mosquitoes and have little or no reaction to their bites, while others can become hyper-sensitive with bites causing blistering, bruising, and large inflammatory reactions, a response known as skeeter syndrome . One study found Dengue virus and Zika virus altered
12420-453: The innate immune system in order to cause persistent infection in mosquitoes and a broad spectrum of diseases in humans. The data on transmissibility via insect vectors of hepatitis C virus, also belonging to family Flaviviridae (as well as for hepatitis B virus, belonging to family Hepadnaviridae ) are inconclusive. WHO states that "There is no insect vector or animal reservoir for HCV", while there are experimental data supporting at least
12555-537: The insecticide. Indoor spraying can be combined with spraying the exterior of the building to help reduce the number of mosquito larvae and subsequently, the number of adult mosquitoes. This measure works excellently in city and urban areas where with running water people don't have the need of indoor water containers for their daily consumption for: First. according to the mosquito rearing protocol, one larval mosquito habitat could release 1,000 adult mosquitoes in 6–10 days. That means about 100 mosquitoes could emerge from
12690-433: The interplay between the microtubule/actin filament complex. The continuous changes in shape from the unactivated to the fully activated platelet are best seen via scanning electron microscopy . The three steps along this path are named early dendritic , early spread, and spread . The surface of the unactivated platelet looks similar to the surface of the brain–a wrinkled appearance from numerous shallow folds that increase
12825-408: The interruption is physically too large, they plug the hole. First, platelets attach to substances outside the interrupted endothelium: adhesion . Second, they change shape, turn on receptors and secrete chemical messengers : activation . Third, they connect to each other through receptor bridges: aggregation . Formation of this platelet plug (primary hemostasis) is associated with activation of
12960-455: The largest source of soluble CD40L which induces production of reactive oxygen species (ROS) and upregulate expression of adhesion molecules, such as E-selectin , ICAM-1 , and VCAM-1 , in neutrophils, activates macrophages and activates cytotoxic response in T and B lymphocytes . Mammalian platelets lacking nucleus are able to conduct autonomous locomotion. Platelets are active scavengers, scaling walls of blood vessels and reorganising
13095-462: The lifespan of mosquitos as well as the rate and frequency of reproduction. Climate change impacts have been of great interest to those studying these diseases and their vectors. Additionally, climate impacts mosquito blood feeding patterns as well as extrinsic incubation periods. Climate consistency gives researchers an ability to accurately predict annual cycling of the disease but recent climate unpredictability has eroded researchers' ability to track
13230-536: The malaria parasite Plasmodium falciparum alters the mosquito vector's feeding behavior by increasing frequency of biting in infected mosquitoes, thus increasing the chance of transmitting the parasite. The mechanism of transmission of this disease starts with the injection of the parasite into the victim's blood when malaria-infected female Anopheles mosquitoes bite into a human being. The parasite uses human liver cells as hosts for maturation where it will continue to replicate and grow, moving into other areas of
13365-842: The mammalian host induces hatching of the larvae. Some species of mosquito can carry the filariasis worm, a parasite that causes a disfiguring condition (often referred to as elephantiasis ) characterized by a great swelling of several parts of the body; worldwide, around 40 million people are living with a filariasis disability. The viral diseases yellow fever , dengue fever , Zika fever and chikungunya are transmitted mostly by Aedes aegypti mosquitoes. Other viral diseases like epidemic polyarthritis , Rift Valley fever , Ross River fever , St. Louis encephalitis , West Nile fever , Japanese encephalitis , La Crosse encephalitis and several other encephalitic diseases are carried by several different mosquitoes. Eastern equine encephalitis (EEE) and Western equine encephalitis (WEE) occur in
13500-559: The mosquito vector, and the affected community, a variety of prevention methods may be deployed at one time. Mosquito borne diseases are indirectly contagious, a mosquito needs to get infected from biting a patient first than transfer it to the next thus, they both need to be in the general area. Mosquito control measures during the Panama canal construction provide the only successful case study of reducing from outbreak status s to zero-malaria and zero-yellow fever, where among applied measures
13635-607: The mosquito's feeding pattern. The ITNs continue to offer protection, even after there are holes in the nets, because of their excito-repellency properties which reduce the number of mosquitoes that enter the home. The World Health Organization (WHO) recommends treating ITNs with the pyrethroid class of insecticides. There is an emerging concern of mosquito resistance to insecticides used in ITNs. Twenty-seven (27) sub-Saharan African countries have reported Anopheles vector resistance to pyrethroid insecticides. Indoor spraying of insecticides
13770-404: The mosquito's increasing ability to adapt to urban settings, the disruption of traditional land use and the inability to control expanding mosquito populations. Like malaria, arboviruses do not have a vaccine. (The only exception is yellow fever.) Prevention is focused on reducing the adult mosquito populations, controlling mosquito larvae and protecting individuals from mosquito bites. Depending on
13905-402: The mosquito, which remains infected for life. Dengue can also be transmitted via infected blood products and through organ donation . Vertical transmission (from mother to child) during pregnancy or at birth has been reported. The principal risk for infection with dengue is the bite of an infected mosquito. This is more probable in areas where the disease is endemic, especially where there
14040-692: The need for wells or street pumps and water-carrying containers. As of March 2024, there are two vaccines to protect against dengue infection; Dengvaxia and Qdenga. Dengvaxia (formerly CYD-TDV) became available in 2015, and is approved for use in the US, EU and in some Asian and Latin American countries. It is an attenuated virus, is suitable for individuals aged 6–45 years and protects against all four serotypes of dengue. Due to safety concerns about antibody-dependent enhancement (ADE), it should only be given to individuals who have previously been infected with dengue, in order to protect them from reinfection. It
14175-463: The number of adult mosquitoes. There is a vaccine for yellow fever which was developed in the 1930s, the yellow 17D vaccine , and it is still in use today. The initial yellow fever vaccination provides lifelong protection for most people and provides immunity within 30 days of the vaccine. Reactions to the yellow fever vaccine have included mild headache and fever, and muscle aches. There are rare cases of individuals presenting with symptoms that mirror
14310-433: The other to form the final fibrin-crosslinked thrombus. Collagen-mediated GPVI signalling increases the platelet production of thromboxane A2 (TXA2) and decreases the production of prostacyclin . This occurs by altering the metabolic flux of platelet's eicosanoid synthesis pathway, which involves enzymes phospholipase A2 , cyclo-oxygenase 1 , and thromboxane-A synthase . Platelets secrete thromboxane A2, which acts on
14445-498: The others. Subsequent infection with a different type increases the risk of severe complications. The symptoms of dengue resemble many other diseases including malaria , influenza , and Zika . Blood tests are available to confirm the diagnosis including detecting viral RNA , or antibodies to the virus. There is no specific treatment for dengue fever. In mild cases, treatment is focused on treating pain symptoms. Severe cases of dengue require hospitalisation; treatment of acute dengue
14580-481: The period mosquitoes are most active. Placing screens on windows and doors is a simple and effective means of reducing the number of mosquitoes indoors. Anticipating mosquito contact and using a topical mosquito repellant with icaridin or DEET is also recommended. Draining or covering water receptacles, both indoor and outdoors, is also a simple but effective prevention method. Removing debris and tires, cleaning drains, and cleaning gutters help larval control and reduce
14715-413: The platelet activator ADP . Resting platelets maintain active calcium efflux via a cyclic AMP -activated calcium pump. Intracellular calcium concentration determines platelet activation status, as it is the second messenger that drives platelet conformational change and degranulation. Endothelial prostacyclin binds to prostanoid receptors on the surface of resting platelets. This event stimulates
14850-504: The platelet by inactivating the cAMP calcium efflux pump. The other ADP-receptor P2Y1 couples to Gq that activates phospholipase C-beta 2 ( PLCB2 ), resulting in inositol 1,4,5-trisphosphate (IP3) generation and intracellular release of more calcium. This together induces platelet activation. Endothelial ADPase degrades ADP and prevents this from happening. Clopidogrel and related antiplatelet medications also work as purinergic receptor P2Y12 antagonists . Data suggest that ADP activates
14985-441: The platelet membrane. Platelet activation causes its membrane surface to become negatively charged. One of the signaling pathways turns on scramblase , which moves negatively charged phospholipids from the inner to the outer platelet membrane surface. These phospholipids then bind the tenase and prothrombinase complexes, two of the sites of interplay between platelets and the coagulation cascade. Calcium ions are essential for
15120-447: The platelet's own thromboxane receptors on the platelet surface (hence the so-called "out-in" mechanism), and those of other platelets. These receptors trigger intraplatelet signaling, which converts GPIIb/IIIa receptors to their active form to initiate aggregation . Platelets contain dense granules , lambda granules, and alpha granules . Activated platelets secrete the contents of these granules through their canalicular systems to
15255-406: The platelet, overcoming the baseline calcium efflux. Families of three G proteins (Gq, Gi, G12) operate together for full activation. Thrombin also promotes secondary fibrin-reinforcement of the platelet plug. Platelet activation in turn degranulates and releases factor V and fibrinogen , potentiating the coagulation cascade. Platelet plugging and coagulation occur simultaneously, with each inducing
15390-409: The platelets aggregate, increasing light transmission, which is detected by a photocell. Whole blood impedance aggregometry (WBA) measures the change in electrical impedance between two electrodes when platelet aggregation is induced by an agonist. Whole blood lumiaggregometry may increase the test sensitivity to impairment of platelet granule secretion. The PFA-100 (Platelet Function Assay — 100)
15525-501: The population average between 250,000 and 260,000 cells per mm (equivalent to per microliter), but the typical laboratory accepted normal range is between 150,000 and 400,000 cells per mm or 150–400 × 10 per liter. On a stained blood smear , platelets appear as dark purple spots, about 20% of the diameter of red blood cells. The smear reveals size, shape, qualitative number, and clumping . A healthy adult typically has 10 to 20 times more red blood cells than platelets. Bleeding time
15660-768: The population, and consequently the disease incidence, is reduced over time. Used successfully for decades to combat fruit flies and livestock pests such as screwworm and tsetse flies , the technique can be adapted also for some disease-transmitting mosquito species. Pilot projects are being initiated or are under way in different parts of the world. Mosquito-borne diseases, such as dengue fever and malaria , typically affect developing countries and areas with tropical climates. Mosquito vectors are sensitive to climate changes and tend to follow seasonal patterns. Between years there are often dramatic shifts in incidence rates. The occurrence of this phenomenon in endemic areas makes mosquito-borne viruses difficult to treat. Dengue fever
15795-466: The presence of [PCR]-detectable hepatitis C viral RNA in Culex mosquitoes for up to 13 days. Currently, there are no specific vaccine therapies for West Nile virus approved for humans; however, vaccines are available and some show promise for animals, as a means to intervene with the mechanism of spreading such pathogens. Doctors can typically identify a mosquito bite by sight. A doctor will perform
15930-452: The process. In case of imbalance throughout the regulation of immunothrombosis, this process can become aberrant. Regulatory defects in immunothrombosis are suspected to be a major factor in pathological thrombosis in forms such as disseminated intravascular coagulation (DIC) or deep vein thrombosis . DIC in sepsis is a prime example of both the dysregulated coagulation process as well as an undue systemic inflammatory response, resulting in
16065-547: The rays they emit, so do mosquitoes, they must be able to see our warmth, or our thermal images because warmth is an obligatory condition they are on the hunt and because electromagnetic radiation is the only media that has miles long atmospheric reach. then for the trap to target only female mosquitoes it must utilize their capacity to see thermal images to use warmth as attractant or a warm lure such as:. with distinct preferences, between side-by-side 37 °C, 40 °C and 42 °C thermal image footprints, they choose to go to
16200-671: The risk of bleeding complications. For moderate illness, those who can drink, are passing urine, have no warning signs and are otherwise reasonably healthy can be monitored carefully at home. Supportive care with analgesics, fluid replacement, and bed rest are recommended. Severe dengue is a life-threatening emergency, requiring hospitalization and potentially intensive care. Warning signs include dehydration , decreasing platelets and increasing hematocrit . Treatment modes include intravenous fluids, and transfusion with platelets or plasma. Most people with dengue recover without any ongoing problems. The risk of death among those with severe dengue
16335-464: The risk of developing a severe form of the disease. Other risk factors for severe disease include female sex, and high body mass index , Infection with one serotype is thought to produce lifelong immunity to that type, but only short-term protection against the other three. Subsequent re-infection with a different serotype increases the risk of severe complications due to phenomenon known as antibody-dependent enhancement (ADE). The exact mechanism of ADE
16470-617: The same mode of transmission ( Aedes mosquitoes) and are often endemic in the same regions, so that it is possible to be infected simultaneously by more than one disease. For travellers, dengue fever diagnosis should be considered in anyone who develops a fever within two weeks of being in the tropics or subtropics . Warning symptoms of severe dengue include abdominal pain, persistent vomiting, odema, bleeding, lethargy, and liver enlargement. Once again, these symptoms can be confused with other diseases such as malaria, gastroenteritis, leptospirosis, and typhus. Blood tests can be used to confirm
16605-461: The skin bacteria of rats in a way that caused their body odor to be more attractive to mosquitoes. Symptoms of illness are specific to the type of viral infection and vary in severity, based on the individuals infected. Symptoms vary in severity, from mild unnoticeable symptoms to more common symptoms like fever, rash, headache, achy muscle and joints, and conjunctivitis. Symptoms can last several days to weeks, but death resulting from this infection
16740-691: The subendothelial collagen by von Willebrand factor (VWF), which these cells produce. VWF is also stored in the Weibel-Palade bodies of the endothelial cells and secreted constitutively into the blood. Platelets store vWF in their alpha granules. When the endothelial layer is disrupted, collagen and VWF anchor platelets to the subendothelium. Platelet GP1b-IX-V receptor binds with VWF; and GPVI receptor and integrin α2β1 bind with collagen. The intact endothelial lining inhibits platelet activation by producing nitric oxide , endothelial- ADPase , and PGI 2 (prostacyclin). Endothelial-ADPase degrades
16875-487: The surface area; early dendritic , an octopus with multiple arms and legs; early spread , an uncooked frying egg in a pan, the "yolk" is the central body; and the spread , a cooked fried egg with a denser central body. These changes are all brought about by the interaction of the microtubule/actin complex with the platelet cell membrane and open canalicular system (OCS), which is an extension and invagination of that membrane. This complex runs just beneath these membranes and
17010-417: The symptoms, such as the fever, the flu-like symptoms, and the severe pains. In severe infection, the virus production inside the body is greatly increased, and many more organs (such as the liver and the bone marrow ) can be affected. Fluid from the bloodstream leaks through the wall of small blood vessels into body cavities due to increased capillary permeability . As a result, blood volume decreases, and
17145-440: The thrombosis site. Platelet concentration in the blood (i.e. platelet count), can be measured manually using a hemocytometer , or by placing blood in an automated platelet analyzer using particle counting, such as a Coulter counter or optical methods. Most common blood testing methods include platelet count in their measurements, usually reported as PLT . Platelet concentrations vary between individuals and over time, with
17280-409: The thrombus. They are able to recognize and adhere to many surfaces, including bacteria, and can envelop them in their open canalicular system (OCP), leading to a proposal to name the process as covercytosis (OCS) rather than phagocytosis, as OCS is merely an invagination of outer plasma membrane. These platelet-bacteria bundles provide an interaction platform for neutrophils that destroy bacteria using
17415-638: The urban environment, is generally found close to human habitation, prefers humans as its host, and takes advantage of small bodies of standing water (such as tanks and buckets) in which to breed. In rural settings the virus is transmitted to humans by A. aegypti and other related mosquitoes such as Aedes albopictus . Both these species have expanding ranges. There are two subspecies of Aedes aegypti , where Aedes aegypti formosus can be found in natural habitats such as forests and Aedes Aegypti aegypti has adapted to urban domestic habitats. Dengue has increased in incidence in recent decades, with WHO recording
17550-493: The velocity of blood flow (i.e. shear range). Platelets have a central role in innate immunity , initiating and participating in multiple inflammatory processes, directly binding and even destroying pathogens. Clinical data show that many patients with serious bacterial or viral infections have thrombocytopenia , thus reducing their contribution to inflammation. Platelet-leukocyte aggregates (PLAs) found in circulation are typical in sepsis or inflammatory bowel disease , showing
17685-525: The virus enters the skin together with the mosquito's saliva. The virus infects nearby skin cells called keratinocytes , as well as specialized immune cell located in the skin, called a Langerhans cells . The Langerhans cells migrate to the lymph nodes , where the infection spreads to white blood cells , and reproduces inside the cells while they move throughout the body. The white blood cells respond by producing several signaling proteins, such as cytokines and interferons , which are responsible for many of
17820-472: The virus. There are four confirmed strains of the virus, called serotypes , referred to as DENV-1, DENV-2, DENV-3 and DENV-4. The distinctions between the serotypes are based on their antigenicity . Dengue virus is most frequently transmitted by the bite of mosquitos in the Aedes genus, particularly A. aegypti . They prefer to feed at dusk and dawn, but they may bite and thus spread infection at any time of day. Other Aedes species that may transmit
17955-434: The warmer first. A 42 °C trap in front of a house will have its font yard mosquito-bite-free area for humans and mammal pets but not birds for their body temperatures are also at 42 °C. There are other methods that an individual can use to protect themselves from mosquito bites. Limiting exposure to mosquitoes from dusk to dawn when the majority of mosquitoes are active and wearing long sleeves and long pants during
18090-405: Was accidentally introduced into the US in 1999 and by 2003 had spread to almost every state with over 3,000 cases in 2006. Other species of Aedes as well as Culex and Culiseta are also involved in the transmission of disease. Myxomatosis is spread by biting insects, including mosquitoes. A mosquito's period of feeding is often undetected; the bite only becomes apparent because of
18225-442: Was developed as a test of platelet function by Duke in 1910. Duke's test measured the time taken for bleeding to stop from a standardized wound in the ear lobe that was blotted every 30 seconds, considering less than 3 minutes as normal. Bleeding time has low sensitivity and specificity for mild to moderate platelet disorders and is no longer recommended for screening. In multiple electrode aggregometry , anticoagulated whole blood
#612387