Prevalence and factors associated with cryptosporidium infection among adult HIV positive population in contact with livestock in Namwala District, Zambia

Cryptosporidiosis is a diarrhoeal disease caused by the parasite, Cryptosporidium that can live in the intestine of humans and animals and is passed in the stool of an infected person or animal. In immune compromised individuals, Cryptosporidium infection can be serious, long-lasting and sometimes fatal. In Zambia, the burden of Cryptosporidium infection in the HIV positive population is unknown and factors associated with this infection are unclear. Therefore, this study was aimed at determining the prevalence of Cryptosporidium spp. and identifying factors associated with infection among the adult HIV positive population in contact with livestock in Namwala district of Zambia.
Concurrent cross-sectional surveys were conducted in human and animal populations. Consenting 270 adults receiving Anti-Retro Viral treatment were interviewed and requested to provide stool samples. Stool samples were also collected from 174 calves aged six months and below. All samples were analyzed for Cryptosporidium infection using the Merifluor® Cryptosporidium/Giardia immunofluorescence assay. Prevalence in humans and animals were estimated, association between the outcome variable and putative risk factors were evaluated using the chi-square test. Logistic regression was used to examine the multiple effects of predictor variables on the outcome. The overall human prevalence of Cryptosporidium infection was 11.1% (30/270). Among the male participants, 15.6% (16) were positive while 8.3% (14) were positive among females. The frequency of Cryptosporidium infection was high in the age group category 50-59 years (18.8%). Participants that kept animals had a relatively higher prevalence of Cryptosporidium infection (14.2%) compared to those that did not (7.4%) (p= 0.08). Factors identified to be associated with Cryptosporidium infection in the adult HIV positive population were sex and marital status. The odds of male participants being infected was 4.2 compared to females. Marital status predicted infection to Cryptosporidium, with the divorced group (P=0.01) and the widowed group (p=0.05) being at high risk. In animals, 21% (36/174) were positive for Cryptosporidium. Breed (p=0.03) and areas of production, Chitongo and Maala, were associated with Cryptosporidium infection in calves (p = 0.03 and p=0.04, respectively).
The study demonstrated that Cryptosporidium infection is a problem in the adult HIV positive population in Namwala district. The concentration of this burden among males further suggests a need for targeted sensitization programs aiming to reach such most at risk communities of humans and to reduce exposure and control infection in the animals too. However, given that this was a small study, there is need to undertake further studies on larger samples so as to understand other factors that may be associated with Cryptosporidium infection and identify the genotypes prevailing in the population.