An opportunistic infection is an infection caused by pathogens ( bacteria , fungi , parasites or viruses ) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune system (as can occur in acquired immunodeficiency syndrome or when being treated with immunosuppressive drugs , as in cancer treatment ), an altered microbiome (such as a disruption in gut microbiota ), or breached integumentary barriers (as in penetrating trauma ). Many of these pathogens do not necessarily cause disease in a healthy host that has a non-compromised immune system, and can, in some cases, act as commensals until the balance of the immune system is disrupted. Opportunistic infections can also be attributed to pathogens which cause mild illness in healthy individuals but lead to more serious illness when given the opportunity to take advantage of an immunocompromised host.
22-443: List of Fusarium species Fusarium ( /fjuˈzɛəriəm/ ; Audio: ) is a large genus of filamentous fungi , part of a group often referred to as hyphomycetes , widely distributed in soil and associated with plants. Most species are harmless saprobes , and are relatively abundant members of the soil microbial community. Some species produce mycotoxins in cereal crops that can affect human and animal health if they enter
44-442: A spindle . The taxonomy of the genus is complex. A number of different schemes have been used, and up to 1,000 species have been identified at times, with approaches varying between wide and narrow concepts of speciation ( lumpers and splitters ). Phylogenetic studies seven major clades within the genus. There is a proposed concept – widely subscribed by specialists – that would include essentially
66-481: A necrotic ulceration of the gingiva, extending to the alveolar bone has been reported in a granulocytopenic patient. List of Fusarium species This is a list of the fungus species in the genus Fusarium . Many are plant pathogens . As of 2023 August 14 , the GBIF lists up to 396 species, while Species Fungorum lists about 440 species. The Encyclopedia of Life lists 213 species. This list
88-507: A number of economically important plant pathogenic species. Fusarium graminearum commonly infects barley if there is rain late in the season. It is of economic impact to the malting and brewing industries, as well as feed barley. Fusarium contamination in barley can result in head blight , and in extreme contaminations, the barley can appear pink. The genome of this wheat and maize pathogen has been sequenced. F. graminearum can also cause root rot and seedling blight. The total losses in
110-543: A result, HIV infection can lead to progressively worsening immunodeficiency, a condition ideal for the development of opportunistic infection. Because of this, respiratory and central nervous system opportunistic infections, including tuberculosis and meningitis, respectively, are associated with later-stage HIV infection, as are numerous other infectious pathologies. Kaposi's sarcoma, a virally-associated cancer, has higher incidence rates in HIV-positive patients than in
132-494: A strategy usually includes restoration of the immune system as soon as possible, avoiding exposures to infectious agents, and using antimicrobial medications ("prophylactic medications") directed against specific infections. The following may be avoided as a preventative measure to reduce the risk of infection: Individuals at higher risk are often prescribed prophylactic medication to prevent an infection from occurring. A person's risk level for developing an opportunistic infection
154-428: Is approximated using the person's CD4 T-cell count and other indications. The table below provides information regarding the treatment management of common opportunistic infections. Alternative agents can be used instead of the preferred agents. These alternative agents may be used due to allergies, availability, or clinical presentation. The alternative agents are listed in the table below. Treatment depends on
176-552: Is based on the EOL list and was updated with the Species Fungorum list in 2023. Opportunistic infection A wide variety of pathogens are involved in opportunistic infection and can cause a similarly wide range in pathologies. A partial list of opportunistic pathogens and their associated presentations includes: Immunodeficiency or immunosuppression are characterized by the absence of or disruption in components of
198-604: Is one of the most destructive plant diseases of modern times, and caused the commercial disappearance of the once dominant Gros Michel cultivar. A more recent strain also affects the Cavendish cultivars which commercially replaced Gros Michel. It is considered inevitable that this susceptibility will spread globally and commercially wipe out the Cavendish cultivar, for which there are currently no acceptable replacements. Fusarium oxysporum f. sp. narcissi causes rotting of
220-686: Is produced industrially for use as a human food by Marlow Foods, Ltd., and is marketed under the name Quorn in Europe and North America . Fusarium strain flavolapis is also produced as a human food by Nature's Fynd under the name Fy in North America. It is used as a part of Le Bernardin menu in several dishes. Some consumers of fusarium products have shown food allergies similar in nature to peanut and other food allergies. People with known sensitivities to molds should exercise caution when consuming such products. Mass casualties occurred in
242-406: Is usually peptone PCNB agar (peptone pentachloronitrobenzene agar, PPA). For F. oxysporum specifically, Komada's medium is most common. Differential identification is difficult in some strains. Vegetative compatibility group analysis is best for some, is one usable method for others, and requires such a large number of assays that it is too complicated for yet others. Fusarium venenatum
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#1732781046378264-535: The Soviet Union in the 1930s and 1940s when Fusarium -contaminated wheat flour was baked into bread, causing alimentary toxic aleukia with a 60% mortality rate. Symptoms began with abdominal pain , diarrhea , vomiting , and prostration , and within days, fever , chills , myalgias and bone marrow depression with granulocytopenia and secondary sepsis occurred. Further symptoms included pharyngeal or laryngeal ulceration and diffuse bleeding into
286-579: The nails ( onychomycosis ) and in the cornea ( keratomycosis or mycotic keratitis). In humans whose immune systems are weakened in a particular way, ( neutropenia , i.e., very low neutrophils count), aggressive fusarial infections penetrating the entire body and bloodstream (disseminated infections) may be caused by members of the Fusarium solani complex, Fusarium oxysporum , Fusarium verticillioides , Fusarium proliferatum and, rarely, other fusarial species. The isolation medium for Fusaria
308-470: The US of barley and wheat crops between 1991 and 1996 have been estimated at $ 3 billion. Fusarium oxysporum f.sp. cubense is a fungal plant pathogen that causes Panama disease of banana ( Musa spp.), also known as fusarium wilt of banana. Panama disease affects a wide range of banana cultivars , which are propagated asexually from offshoots and therefore have very little genetic diversity. Panama disease
330-470: The ancient cave paintings in Lascaux since 1955, when the caves were first opened to visitors. The caves subsequently closed and the threat subsided, but the installation of an air conditioning system in 2000 caused another outbreak of the fungus which is yet to be resolved. Fusarium may be part of microbiota including digestive as well as oral/dental, there have been rare cases of Fusariosis presenting as
352-480: The bulbs (basal rot) and yellowing of the leaves of daffodils ( Narcissi ). In 2021 it was discovered that Fusarium xyrophilum was able to hijack a South American species of yellow-eyed Xyris grass, creating fake flowers, fooling bees and other pollinating insects into visiting them, taking fungal spores to other plants. Some species may cause a range of opportunistic infections in humans. In humans with normal immune systems, fusarial infections may occur in
374-405: The food chain. The main toxins produced by these Fusarium species are fumonisins and trichothecenes . Despite most species apparently being harmless (some existing on the skin as commensal members of the skin flora ), some Fusarium species and subspecific groups are among the most important fungal pathogens of plants and animals . The name of Fusarium comes from Latin fusus , meaning
396-443: The general population. As immune function declines and HIV-infection progresses to AIDS, individuals are at an increased risk of opportunistic infections that their immune systems are no longer capable of responding properly to. Because of this, opportunistic infections are a leading cause of HIV/AIDS-related deaths. Since opportunistic infections can cause severe disease, much emphasis is placed on measures to prevent infection. Such
418-453: The genus as it now stands, including especially all agriculturally significant Fusaria . There is a counterproposal (unrelated to Watanabe 2011 ) that goes far in the other direction, with seven entirely new genera. Various schemes have subdivided the genus into subgenera and sections. There is a poor correlation between sections and phylogenetic clades . Sections previously described include: Selected species include: The genus includes
440-424: The immune system, leading to lower-than-normal levels of immune function and immunity against pathogens. They can be caused by a variety of factors, including: The lack of or the disruption of normal vaginal microbiota allows the proliferation of opportunistic microorganisms and will cause the opportunistic infection bacterial vaginosis . HIV is a virus that targets T cells of the immune system and, as
462-412: The skin ( petechiae and ecchymoses ), melena , bloody diarrhea, hematuria , hematemesis , epistaxis , vaginal bleeding , pancytopenia and gastrointestinal ulceration. Fusarium sporotrichoides contamination was found in affected grain in 1932, spurring research for medical purposes and for use in biological warfare . The active ingredient was found to be trichothecene T-2 mycotoxin , and it
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#1732781046378484-541: Was produced in quantity and weaponized prior to the passage of the Biological Weapons Convention in 1972. The Soviets were accused of using the agent, dubbed " yellow rain ", to cause 6,300 deaths in Laos , Kampuchea , and Afghanistan between 1975 and 1981. The "biological warfare agent" was later purported to be merely bee feces , but the issue remains disputed. Fusarium has posed a threat to
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