Prevalence and molecular characterisation of Giardia spp. and Cryptosporidium spp. at the wildlife-livestock interface in Laikipia, Kenya

Giardia and Cryptosporidium are important causes of diarrhoeal disease in humans, particularly in sub-Saharan Africa, with several species and genotypes capable of zoonotic transmission. Central Laikipia, Kenya, represents a shared landscape characterised by close human-livestock-wildlife interactions. Traditional pastoral systems and commercial ranching coexist alongside high wildlife diversity offering high potential for interspecies disease transmission. Despite this, molecular data on protozoan parasites in animal hosts remains limited across the
region. We collected faecal samples opportunistically from six wildlife and four livestock species over three years in Laikipia and screened them using molecular methods to investigate the sample prevalence and genetic di
versity of Giardia and Cryptosporidium. Giardia occurrence was consistently high, ranging from 21% in in samples from 2022 to 27% in samples from 2025, whereas Cryptosporidium occurrence remained low (0–5%) over the
same period. Multilocus sequencing was partially successful for a subset of samples at the beta-giardin, triosephosphate isomerase, and glutamate dehydrogenase genes. This identified predominantly livestock-adapted
Giardia duodenalis assemblage E, with much lower occurrence of potentially zoonotic assemblages AI and AII in livestock. Sequencing of the 18S SSU gene identified multiple Cryptosporidium species These were mostly ungulate specific species but did include the potentially zoonotic C. ubiquitum. The detection of both ungulate- specific and possibly zoonotic genotypes highlights possible One Health implications within this shared landscape. While potentially zoonotic genotypes indicate there may be public health risk through animal-to-human transmission, the predominance of ungulate-specific genotypes suggests higher potential for animal-to-animal transmission cycles, with potential indirect effects on human health through impacts on livestock productivity
and growth