|
''Mycoplasma haemofelis'' (formerly ''Haemobartonella felis'') is a gram negative epierythrocytic parasitic bacterium. It often appears in bloodsmears as small (0.6μM) coccoid bodies, sometimes forming short chains of 3 to 6 organisms. It is usually the causative agent of Feline Infectious Anemia (FIA) in the United States. The ~1200kb genome contains a minimalistic assortment of genes limited to the most basic cellular functions. This leaves ''M. haemofelis'' inextricably dependent upon its host for the provision of amino acids, cholesterol, vitamins, and fatty acids. The complex and specific conditions the bacterium requires have made it impossible to culture outside a host thus far. Arthropod vectors are thought to be the primary source of infection, although ''M. haemofelis'' is also known to be transmitted from queen to kitten and following blood transfusion. Immunocompromization and/or coinfection with FeLV, FIV, and other ''Mycoplasma'' species can exacerbate symptoms or cause symptoms to arise in previously asymptomatic individuals. Symptoms include anemia, lethargy, fever, and anorexia. In suspected cases, ''M. haemofelis'' can be identified by polymerase chain reaction analysis for species-specific 16S rRNA sequences as well as by light microscopy. Treatment usually includes the administration of doxycycline or enrofloxacin to quell the infection along with transfusion and administration of glucocorticoids to alleviate anemia.〔 Recent evidence suggests that ''M. haemofelis'' may be transmissible to humans. == Classification == ''M. haemofelis'' belongs to the phylogenetically diverse class Mollicutes, which comprises 8 genera: ''Ureaplasma'', ''Spiroplasma'', ''Asteroleplasma'', ''Mesoplasma'', ''Entomoplasma'', ''Acholeplasma'', ''Anaeroplasma'', and ''Mycoplasma''. Haemoplasmas is the name given to the trivial cluster that includes ''M. haemofelis'' and its close relatives.〔 Before the advent of modern PCR techniques, ''M. haemofelis'' and closely related Haemoplasmas ''Candidatus Mycoplasma haemominutum'' and ''Candidatus Mycoplasma turicensis'' were collectively classified as ''Haemobartonella felis'' based on similarities in gross morphology. The ''Candidatus'' distinction is given to newly described species in which additional evidence is required to support their classification. The inability of researchers to culture many ''Mycoplasma spp.'' ''in vitro'' has made classification difficult. PCR analysis of 16S rRNA sequences of ''Haemobartonella spp.'' showed greater similarity to those of Mollicutes than to those of the family Anaplasmataceae in the order Rickettsiales to which they were previously thought to belong. PCR-based assays have provided evidence that the Ohio variant and California variant of ''H. felis'' are in fact distinct species, ''M. haemofelis'' and ''Candidatus Mycoplasma haemominutum'' respectively. A third Haemoplasma, ''Mycoplasma turicensis'', was later identified in domestic cats. Haemoplasma species have also been identified in dogs (''M. haemocanis''), mice (''M. haemomuris''), opossum (''Candidatus M. haemodidelphis''), and alpaca (''Candidatus M. haemolamae''). In cats, ''M. haemofelis'' is the most virulent Haemoplasma species and is most often implicated in FIA in the United States. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mycoplasma haemofelis」の詳細全文を読む スポンサード リンク
|