Abstract:
This prospective study on Cryptosporidium and cryptosporidiosis was carried out in
the North Rift region of Kenya. Cryptosporidium parasites are leading causes of
enteric disease, more so in children and HIV infected individuals. A total of 317
fecal samples from children less than five years of age, and 1794 fecal samples from
HIV infected persons seen at Moi referral and Teaching Hospital, Eldoret and at two
health centres in the North Rift region of Kenya were collected over a period of one
year covering January to December 2005. This study area was chosen because there
are no reports on the burden of cryptosporidiosis in this region and therefore the
results this study highlight this burden and contribute towards the general picture of
cryptosporidiosis in Kenya. Overall prevalence of cryptosporidiosis in children was
9.8% and among HIV infected individuals it was 3.2%. The highest prevalence was
observed between March and April, and a smaller peak between June and July. Both
periods corresponded to the relatively dry seasons in the North Rift region of Kenya.
The rate of diarrhea in the HIV positive individuals was 35.1% with a
cryptosporidiosis prevalence of 6.5%. Cryptosporidiosis was significantly associated
with diarrhea (OR= 4.7087, P≤0.002), skin rash among HIV positive individuals
(OR= 2.2145, P=0.0033) and headache (OR= 1.8087, P= 0.0279). However, other
symptoms such as abdominal pains, cough, fever and vomiting were not significantly
associated with cryptosporidiosis, in both the pediatric and HIV positive study
groups. In the pediatric group all subjects were diarrheic and duration of diarrhea of
more than two weeks was more likely to be associated with the presence of
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cryptosporidiosis (OR= 1.8301) when compared to those with diarrhea for less than
one week.
There were no significant sex related differences observed in the cryptosporidiosis
prevalence in the children (P= 0.9752) or in the HIV positive persons (P= 0.5029).
Similarly, environmental factors such as location of residence, waste disposal, water
sources and treatment, presence of animals in homesteads or household size were not
significantly associated with cryptosporidiosis.
Genotype analysis based on polymerase chain reaction and restriction fragment
length polymorphism (PCR-RFLP) of the 18S rRNA gene fragment revealed that
among the children about 82% of the isolates were C. hominis and nearly 18% were
C. parvum. Among the HIV infected persons, on the other hand, about 68% of the
isolates were C. hominis, about 14% C. meleagridis, and 18% were C. parvum.
Based on the trinucleotide sequence analysis there were 12 subtypes of C. hominis and 7
subtypes of C. parvum in circulation in the North Rift region of Kenya.
The results suggest that cryptosporidiosis prevalence is comparable to other regions
of the world with C. hominis being the most common species circulating study area
followed by C. parvum and C. meleagridis in that order. Mixed C. hominis and C.
parvum infections also occurred, and constituted about 1% of the infections. These
results suggest that human-to-human transmission is the main mode of spread of
cryptosporidiosis in the region.