Prevalence and risk factors of cystic echinococcosis in cattle and humans in Western Province of Zambia
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Cystic echinococcosis or hydatidosis is caused by the larval stage of the tapeworm Echinococcus granulosus, is one of the most important parasitic infestations in livestock worldwide and one of the most important parasitic zoonoses. A crosssectional study was conducted to estimate the prevalence of hydatidosis in cattle and humans of Western Province of Zambia and determine the risk factors associated with disease occurrence. A retrospective analysis of cattle slaughter data from an eleven year period 1994 to 2007 (except for 1997, 1998 and 2002) was done to determine the presence of hydatid cysts in cattle. A retrospective review of, records of human cystic echinococcosis from Lewanika General Hospital, which is a referral centre for Western Province over four year period (2006 to 2010) was conducted and analyzed to determine the prevalence of the parasite in humans. Disease prevalence in cattle in various districts and camps was done by post mortem examination conducted from October 2007 to November 2008. The viability and fertility tests were done on some of the cysts collected during the study. A questionnaire survey to identify risk factors of transmission was also carried out. Annual losses due to abattoir condemnation of organs were estimated to determine the direct economic loss due to the disease. A total of 158,456 cattle were slaughtered and inspected out of which, 4689 (3.0%) cases of bovine hydatidosis were recorded. The lung accounted for 93.7 %, followed by liver at 6.26 % and spleen at 0.02 %. Proportion positive in humans was 0.009 % (9 per 100,000 cases attended to). Sixty-seven percent of the human cases diagnosed were in females and 33% in male humans. Hydatidosis was prevalent in 2.1% of the cattle slaughtered in two abattoirs in Western province during the prospective study. District prevalence were at 2.5%, 2.1%, 1.4% and 0.6% for Mongu, Senanga, Kalabo and Lukulu, respectively. In the questionnaire survey, it was observed that 88% of the households owned at least one dog. Among those that kept dogs (n= 58), the majority (96.6%) of dogs were in the free range system. Most dogs were mostly kept for security (86.2%) and cattle herding (87.9%). Stray dogs in the communities were regularly spotted by 65% of respondents. Most of the HH (94.8%) admitted to feeding offal to dogs and 37.9% of the respondents reported dogs scavenging from abattoirs and local slaughter slabs. It was observed that 98% of the households had dogs that defecated in the immediate surroundings of their dwelling places. It was found that the liver had 43.7% and the lung had 43% fertile cysts. The overall percentage of fertile cysts was found to be 43.1%. The estimated annual loss associated with organ condemnation was evaluated at K 15, 894, 000 (U$3,311) annually. The study has established that hydatidosis is prevalent in cattle and humans in Western Province of Zambia and that the risk factors for its transmission exist. The disease also contributes to economic losses due to organ condemnations and is of public health concern.
- Veterinary Medicine