Genetic homogeneity of goat malaria parasites in Asia and Africa suggests their expansion with domestic goat host

Plasmodium was first identified in a goat in Angola in 1923, and only recently characterized by DNA isolation from a goat blood sample in Zambia. Goats were first domesticated in the Fertile Crescent approximately 10,000 years ago, and are now globally distributed. It is not known if the Plasmodium identified in African goats originated from parasites circulating in the local ungulates, or if it co-evolved in the goat before its domestication. To address this question, we performed PCR-based surveillance using a total of 1,299 goat blood samples collected from Sudan and Kenya in Africa, Iran in west Asia, and Myanmar and Thailand in southeast Asia. Plasmodium DNA was detected from all locations, suggesting that the parasite is not limited to Africa, but widely distributed. Whole mitochondrial DNA sequences revealed that there was only one nucleotide substitution between Zambian/Kenyan samples and others, supporting the existence of a goat-specific Plasmodium species, presumably Plasmodium caprae, rather than infection of goats by local ungulate malaria parasites. We also present the first photographic images of P. caprae, from one Kenyan goat sample.