Review on the Epidemiology and Public Health Importance of Giardiasis

Abstract

Abdusalam Yaya Yusuf(DVM) and Mohammed Bedruddin Aliyi(DVM)

Giardia is a protozoan parasite of mammals including humans. It is one of the most common parasitic infections hav- ing a worldwide distribution. Giardia parasites have a wide host range, including mammals, birds and amphibians. Amongst the species of Giardia, G. duodenalis (syn, G. intestinalis/lamblia) has the broadest host range and is the species with the greatest public and animal health significances in terms of gastrointestinal disease. Humans have been reported to have G. duodenalis Assemblages A-II or B, and these assemblages are considered to be of broad host ranges, and thus potentially zoonotic due to infect both human and other domestic and wild animals. Aquatic mammals, is commonly infected with Giardia, there is little evidence to implicate such infections as the original con- taminating source in waterborne outbreaks. Giardia lamblia infections have a wide clinical spectrum ranging from asymptomatic carriage to long-lasting diarrhea with malabsorption. So far, it remains unclear whether asymptomatic human infections relate to the carriage of "nonpathogenic" strains, or whether the host is able to maintain parasite numbers at a subclinical level without complete clearance of the infection. There are four main cycles of transmission that have been proposed to maintain host-specific and zoonotic assemblages of Giardia in mammalian hosts: human, livestock, dog/cat and wildlife cycles. Water is an essential factor in the transmission of giardiasis in men that is why this is the commonest human waterborne disease. Future studies by animal and public health experts should focus on genetic characterization of the parasite so as to elucidate the zoonotic importance of Giardia. More extensive research is necessary among humans, animals and water sources with regard to Giardia carriership. The obtained isolates should be genotyped in order to investigate the sources of contamination and to undertake efficient measures for reduction of infection rates in both animals and people.

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