First molecular detection of Sarcocystis suihominis in a domestic pig of Nigeria.

Sarcocystis are Apicomplexan protozoa with a dixenous life cycle that includes a predator and a prey as definitive and intermediate hosts, respectively. Domestic and wild pigs are intermediate hosts of S. suihominis, with formation of sarcocysts in their muscles, while humans and non-human primates act as final hosts. After ingesting raw or undercooked sarcocyst-infested pork, signs of gastroenteritis including inappetence, nausea, vomiting, and diarrhea may develop in humans. Moreover, excretion of infective forms with human feces leads to dissemination of the parasite in the environment. In this study, macroscopic sarcocysts of white color, oval shape, and a diameter of approximately 3-8 mm were found in the skeletal muscle of a slaughtered domestic pig (Sus scrofa domesticus) destined for human consumption in an abattoir of Makurdi, Benue State, Nigeria. Sarcocyst DNA was used as template to PCR amplify the near-complete length of the 18S rRNA gene and a fragment of the cytochrome c oxidase subunit 1 (cox-1) gene. Amplicons were sequenced and used to construct phylogenetic trees with selected available Sarcocystis spp. sequences. In both cases, the placement of the analyzed sequences with S. suihominis was strongly supported, confirming the species identity of this macroscopic sarcocyst-forming parasite. This constitutes the first molecular identification of S. suihominis in Nigeria and the African continent. Proximity between pigs and humans, and poor sanitary conditions frequently encountered in pig farms of Nigeria might favor the dissemination of this zoonotic parasite, posing a threat to public health.

Comparative morphometric analysis of the gastrointestinal tract of the captive greater cane rat (Thryonomys swinderianus) and African giant pouched rat (Cricetomys gambianus).

The greater cane rats (Thryonomys swinderianus) and African giant pouched rats (Cricetomys gambianus) are among the largest rodents in Africa, undergoing domestications for meat and research purposes. The aim of this study was to explore whether there are any quantitative anatomical gastrointestinal adaptations associated with their omnivorous or herbivorous diets. In the African giant rat, the mean gastrointestinal tract length and colon width of the males were significantly higher than their females counterpart (P < 0.05 and P < 0.01, respectively). In a similar way, the mean gastrointestinal tract weight, stomach length and jejunal width in males greater cane rat were significantly higher than in the females (P < 0.05, P < 0.01 and P < 0.01 respectively). The monogastric, omnivores African giant pouched rats had mean significant stomach length and width than greater cane rat (P < 0.01 and P < 0.01 respectively). Also, the duodenal length, jejunal and ileal widths were higher in the former than in the latter (P < 0.05, P < 0.05 and P < 0.01 respectively). The monogastric, herbivore greater cane rats had higher mean cecal width and colon length than the African giant pouched rat (P < 0.01 and P < 0.01 respectively). In conclusion, the African giant pouched rat had larger stomach and longer and wider small intestine, compared to the greater cane rat, which instead had more prominent cecum and wider and longer colon. This suggests that greater cane rats are hindgut fermenting herbivores (cecal fermenter), as is the case in most rodent species.