Identifying the sources of human campylobacteriosis in Nigeria.

Campylobacter spp. have been shown to be the most common cause of bacterial gastroenteritis worldwide. Cases of human campylobacteriosis are usually reported as sporadic and not part of an outbreak which makes the identification of the source of infection difficult. A study of the relationships within isolate populations in Nigeria and source attribution analysis of Nigerian human Campylobacter spp. to other animal isolates was carried out to determine the possible sources for human Campylobacter infection in Nigeria. The results showed nine sequence types (STs) common to both humans and livestock isolated from abattoirs, farms and live bird markets with similar STs clustering together on a phylogenetic tree, confirming a degree of genetic similarity. Source attribution analysis suggests wild birds as the most important reservoir (38%) for human Campylobacter spp. infection in Nigeria followed by chicken (23%), pig (19%), cattle (11%) and sheep (8%). This might be an indication of the importance of this infection source to humans in Nigeria and probably other low-income countries due to farming practices and human habits.