Marked seasonality of Cyclospora cayetanensis infections: Ten-year observation of hospital cases, Honduras

Background: Document seasonality occurrence and epidemiologic characteristics of Cyclospora cayetanensis infections during a 10-year period from patients consulting at the University Hospital, Honduras. Methods: Retrospective non interventional hospital-based study analyzed laboratory results from the period 2002 to 2011 of fresh and Ziehl-Nielsen carbolfuchsin stained routine stool samples received for parasitologic examination. Sporadically a sample with numerous oocysts was allowed to sporulate in 2.5 % potassium dichromate confirming the presence of bi-cystic bi-zoic oocysts. Results: A total of 35,157 fecal samples were examined during a ten-year span, of which a third (28.4 %) was stained by the Ziehl-Neelsen carbolfuchsin method diagnosing a total of 125 (1.3 %) C.cayetanensis infections. A statistically significant apparent seasonality was observed most years during May to August (range p < 0.036-0.001), with 83.3 % of 125 cases occurring in those rainy months. All C. cayetanensis cases came from urban poor neighborhoods; male/female relation was 1:1 except in 2006, when all patients were females (p = 0.05; r² = 22,448). Forty four point eight percent of the stool samples were diarrheic or liquid and 65.6 % infections were identified in children 10 years old or less. Enteric helminths and protozoa co-infected Cyclospora positive patients in 52 instances.: 8 % Ascaris lumbricoides, 8 % Giardia duodenalis, 23.2 % Blastocystis spp. and less frequently Entamoeba histolytica/E. dispar, Strongyloides stercoralis, and Trichuris trichiura. Conclusions: Results suggest a seasonal pattern for Cyclospora infections diagnosed in a clinical setting during the rainy months in Tegucigalpa and surrounding areas. Community studies should be conducted to support or dispute these observations.