Epidemiology of Cyclospora cayetanensis and other intestinal parasites in a community in Haiti

Abstract

We conducted an exploratory investigation in a community in Haiti to determine the prevalence of Cyclospora cayetanensis infection and to identify potential risk factors for C. cayetanensis infection. In 2001, two cross-sectional stool surveys and a nested case-control study were conducted. In 2002, a follow-up cross-sectional stool survey was conducted among children < or =10 years of age. Stool specimens from study participants and water samples from their wells were examined for Cyclospora and other intestinal parasites. In stools, the prevalence of infection with Cyclospora in persons of all ages decreased from 12% (20 of 167 persons) in February 2001 to 1.1% (4 of 352 persons) in April 2001, a 90.8% decrease. For children < or =10 years of age, the prevalence rates were 22.5% (16 of 71 children) in February 2001, 3.0% (4 of 135 children) in April 2001, and 2.5% (2 of 81 children) in January 2002. Use of the water from the artesian well in the northern region of the community versus the one in the south was the only risk factor associated with Cyclospora infection in multivariate analyses (odds ratio, 18.5; 95% confidence interval, 2.4 to 143.1). The water sample from one of the nine wells or water sources tested (one sample per source) in January 2001, shortly before the investigation began, was positive for Cyclospora by UV fluorescence microscopy and PCR. None of the water samples from the 46 wells or water sources tested during the investigation (one sample per source per testing period, including the artesian wells) were positive for Cyclospora. Further studies are needed to assess the role of water as a possible risk factor for Cyclospora infection in Haiti and other developing countries.

FIG. 1.

Flow diagram of parts 1, 2, 3, and 4 of an investigation conducted in a community in Haiti from January 2001 to January 2002. For the cross-sectional stool survey of January 2002, stool containers were also given to children who used water from a dug well at a household that participated in part 1 and/or 2 in 2001, regardless of whether the child had participated in that part(s).

FIG. 2.

Map of the study community in Haiti that illustrates the distribution of cases of Cyclospora infection identified during the investigation. The map includes all households that were mapped during the investigation, regardless of whether the household participated in any of the studies. Although it appears that the northern region of the community is much larger than the southern region, the numbers of houses in each region were comparable. Most households in the community had dug wells, and some (an unknown percentage) of the dug wells were covered when not in use.

FIG. 3.

An unlined dug well with a tire ring (A) and a concrete-lined dug well with a concrete ring (B). The construction and quality of the different types of wells varied throughout the community. Examples of variation included the height of the concrete ring; the types, quality, and numbers of tires used for the tire rings; and the materials, if any, used to cover the wells when not in use. Both community members and research staff typically used buckets tied to ropes, such as the ones shown in panels A and B, to retrieve water from the wells.

FIG. 4.

Age distribution among case patients (n = 24; black boxes) and non-case patients (n = 378; white boxes) who participated in part 1 and/or 2. The age of one non-case patient was unknown. Fifty (65.8%) of the 76 persons in the 21- to 30-year age range were women; they are the predominant figures in Haitian households and thus the adults most likely to be home. The percentages (numerator/denominator) of persons in each age group infected with Cyclospora are provided. The prevalence for children ≤10 years of age (i.e., those in age groups of 0 to 5 and 6 to 10 years) was 13.3% (20 of 150).

FIG. 5.

Flow diagram of the types of wells used by case patients and controls. Case patients were more likely to have unlined dug wells, with or without tire rings, than concrete-lined dug wells with cement rings (univariate OR, undefined; P = 0.05). Only one case patient had an unlined dug well without a tire ring.