Abstract

Diarrhea of unknown etiology causes death in human beings, especially children with severe acute malnutrition in Africa including Zambia. Transmission of pathogenic bacteria among wild animals, livestock and people is one of the suspected causes of diseases. In this study, we looked for virulence genes specific to Escherichia coli and Salmonellaspecies, that is, genes encoding enterotoxins (LT and ST1), EAST1, shiga toxin and invasion gene (invA, invB and ipaH) in fecal specimens of Kafue lechwe (Kobus leche kafuensis) antelopes and pastoral cattle in Zambia. The EAST1 gene was detected more frequently in Kafue lechwe (83.3%) than in cattle (33.3%) specimens (p<0.01). In contrast, the stx-2 positive samples in Kafue lechwe (20.0%) had significantly lower percentage than that in cattle (55.1%, p<0.01). There was no significant difference between lechwe antelope and cattle in the distribution of stx-1 gene. Salmonella-specific invA gene was detected in only one sample from cattle.  Genes encoding enterotoxins, that is, LT and ST1, and genes tdh, ipaB, ipaH and virB were absent in all the samples. Our results demonstrate the potential of lechwe faecal materials as a possible vehicle for transmission of diarrheagenic pathogens in the interface areas of Kafue Basin, Zambia. Kafue lechwe seems to be a wild reservoir of enteroaggregative E. coli (EAEC). Wild animals such as Kafue lechwe can bring enteropathogenic bacteria to cattle and human beings in interface areas.

Key words: Enteroaggregative Escherichia coli (EAEC), enterohemorrhagic Escherichia coli (EHEC), Salmonella, EAST1, stx-1/stx-2, invA