Molecular characterization of Echinococcus species in dogs from four regions of Kenya

Abstract

Cystic echinococcosis is endemic both in livestock and humans in many parts of Kenya. However, very little data exists on Echinococcus infections in dogs, and therefore their role in maintaining the transmission cycles and environmental contamination with eggs of Echinococcus species is unknown. The study aimed to establish the prevalence and distribution of Echinococcus granulosus sensu lato causing infection in dogs in Kenya. A total of 1621 dog faecal samples were collected from the environment in four different regions and examined microscopically for the presence of taeniid eggs. Up to 20 individual taeniid eggs per faecal sample were picked, lysed and genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing of the NADH dehydrogenase subunit 1 (nad1) gene. Eleven percent (178/1621) of faecal samples had taeniid eggs, while 4.4% (71/1621) contained Echinococcus spp. eggs. Area-wise, the faecal prevalence of Echinococcus spp. was 9.2% (48/524) in Turkana, 4.0% (20/500) in Maasai Mara, 0.7% (2/294) in Isiolo and 0.3% (1/303) in Meru. E. granulosus sensu stricto (s. s.) was the dominant Echinococcus taxon, followed by E. canadensis (G6/7) that was detected in 51 and 23 faecal samples, respectively. E. ortleppi was detected in only 5 faecal samples. We report for the first time the presence of E. felidis eggs in two dog faecal samples (from Maasai Mara region). Mixed infections of these taxa were also found in faecal samples, including: E. granulosus s. s. and E. canadensis (G6/7) (n = 7), E. granulosus s. s. and E. ortleppi (n = 1) and all three species (n = 1). The dog data presented here confirm the differences in diversity and abundance of Echinococcus spp. between regions of Kenya, correspond well with previously published data from livestock, and tentatively suggest a role of domestic dogs as a link between domestic and sylvatic cycles of Echinococcus spp.

Keywords: Cystic echinococcosis; Dogs; Echinococcus felidis; Echinococcus spp.; Kenya.