Identification of Cyclospora in poultry.

356 Letters coordinating system among agencies at all levels and deal with the threat of widespread , multistate/international foodborne outbreaks caused by infectious or toxic agents. To the Editor: Human infection with the parasitic protozoa, Cyclospora, was first described in 1979 (1), and the organism was only recently categorized as an important gastrointestinal parasite. A single species, Cyclospora cayetanensis, has been described in humans (2), while most species in the genus Cyclospora have been described only in reptiles and rodents (3). The consumption of undercooked meat and exposure to contaminated water have been considered possible sources of human infection with C. cayetanensis (1,4). Coccidia were detected in drinking water in Nepal (5), and the parasite was identified in an animal species (one duck in Peru, by Zerpa et al. [6]) different from those in which it was described earlier. To determine whether a domestic animal is either a host or a reservoir for C. cayetanensis, we first examined feces from cats, which are hosts and reservoirs of Toxoplasma gondii, a coccidia causing human illness, but got negative results. Because Cyclospora were recently phyloge-netically linked to Eimeria mitis and E. tenella (7), coccidial parasites of chickens, we investigated the presence of Cyclospora in poultry. We pooled feces from approximately 600 4-to 6-week-old chickens from a poultry farm near Monterrey, Mexico, and extracted feces from the caecum of 50 6-to 8-week-old chickens from a poultry market at that location. By Percoll discontinuous-gradient centrifugation (Medina-De la Garza et al., submitted), both fecal pools were positive for coccidia, mainly Eimeria species and what we regarded as C. cayetanensis oocysts. by 1) characteristic morphology and size (8µm to 10µm), 2) positive staining with Kinyoun's acid-fast stain, 3) positive autofluorescence under ultraviolet light, and 4) sporulation of oocysts with formation of sporocysts after a 10-day incubation. All these are diagnostic features of C. cayetanensis (8) and to our knowledge are not described for any known poultry coccidia. On the basis of these findings, we suggest that poultry may serve as a possible source for human infection with Cyclospora. Consumption of chicken has been reported in one infected patient in the original description by Ashford (1) and in a patient reported recently by Connor and Shlim (9). Moreover, the only existing report of C. cayetanensis found in feces from a domestic farm animal concerned a farm duck (6). Zerpa et al. suggest that besides consumption of contaminated …