zoonoses and communicable diseases common to ... - PAHO/WHO

326 MYCOSESCRYPTOCOCCOSISICD-10 B45.0 pulmonary cryptococcosis; B45.1 cerebral cryptococcosis;B45.2 cutaneous cryptococcosis; B45.3 osseous cryptococcosis;B45.7 disseminated cryptococcosis; B45.8 other forms of cryptococcosisSynonyms: Torulosis, European blastomycosis, Busse-Buschke’s disease.Etiology: Cryptococcus neoformans (Saccharomyces neoformans, Torulopsisneoformans, Torula histolytica), a saprophytic yeast growing in certain soils. Theagent has a spheroid or ovoid shape, is encapsulated, ranges from 4 to 7 microns indiameter, and is gram-positive. It reproduces by means of buds attached by a delicatebase to the parent cell. Research in recent years has demonstrated that C. neoformanshas a sexual form and is a basidiomycete.Of epidemiological interest is C. neoforman’s subdivision into four serotypes (A,B, C, and D) on the basis of capsular polysaccharide antigens. In turn, the serotypesare categorized in two varieties: C. neoformans var. neoformans (serotypes A and D)and C. neoformans var. gattii (serotypes B and C). In addition to biochemical, serological,and genetic differences, serotypes A and D are different in their perfect (sexual)state from serotypes B and C. Although a few A and D strains can be conjugatedwith B and C, their survival is short-lived (Diamond, 1990).Geographic Distribution: Worldwide. In the Americas the disease has been confirmedin Argentina, Brazil, Canada, Colombia, Mexico, the United States, andVenezuela. Serotype A is prevalent throughout the world. Serotype D is common insome European countries (Denmark, Italy, and Switzerland), but rare in the UnitedStates. In contrast, serotypes B and C are more localized and are recognized as diseaseagents, particularly in southern California, southeastern Oklahoma, and some otherareas of the United States, as well as in Asia (Kaplan et al., 1981; Fromtling et al.,1982). In some regions of Australia, a high percentage of isolated strains have thecharacteristics of the gattii strain, as in the case of the indigenous population in theNorthern Territory. In one study, 25 of 26 isolates (24 of them from meningitispatients) corresponded to gattii. In another study, 21 of 22 strains (95.5%) were alsoof the gattii variety. In South Australia, which has a primarily urban population, 65.2%of 23 strains were classified as gattii (Ellis, 1987). Other sites with a high prevalenceof gattii var. are Brazil (10 of 31 strains) and southern California (30 of 73) (Kwon-Chung and Bennett, 1984). In Argentina, 101 of 105 isolates from 1981–1990 wereclassified as C. neoformans var. neoformans and 4 as var. gattii (serotype B). Thesedata are similar to those found in the United States (Bava and Negroni, 1992).Occurrence in Man: Cases are sporadic, with a higher incidence in men than inwomen. From 1965 to 1997, 1,264 cases of cryptococcosis were documented in theUnited States. Of 848 cases confirmed between 1973 and 1997, 608 patients hadmeningitis and 240 had extrameningeal localizations. These data indicate a greatincrease as compared to earlier periods (Kaufman and Blumer, 1978). There were85 cases in Malaysia between 1974 and 1980, predominantly among ethnic Chinese(Pathmanathan and Soo-Hoo, 1982). In the United States and Europe, cryptococcosisoccurs primarily in patients with immune system defects (especially AIDS) orwho are undergoing immunosuppressant treatment. The prevalence of the disease