Pathology of the gastrointestinal tract in free ranging mountain gorillas

Abstract

The study was done to assess the pathological lesions in the gastrointestinal tract in the free-ranging mountain gorillas in Bwindi Impenetrable National Park and the Virunga Volcanoes of Uganda, Rwanda and the Democratic Republic of Congo (DRC). In the past, a number of non-invasive studies have looked at faecal parasites in these species. This study looked at a variety of gross and histopathological lesions of the gastrointestinal tract and their prevalences. There were 3 (5%) newborns, 17(28.3%) infants, 12 (20%) juveniles, 3 (5%) subadults and 25 (41.1%) adult mountain gorillas in the study. The study involved reviewing of 55 gross reports of individuals and the histopathology of the GIT of 60 animals that died between 1988 and 2007. Grossly, the most prevalent lesion in the oral cavity was pigmentation of the tongue and teeth in 11 (20%) of the individuals. In the stomach, the most prevalent lesion was congestion of the mucosa in 11 (20%) of the animals. Haemorrhage and congestion were the most prevalent lesions in the small intestines and colon in 13 (23.6%) and 8 (16%), respectively. The lesion with the highest prevalence in the caecum and rectum was congestion and haemorrhage of their mucosae in 5 (10%) and 7 (14.9%), respectively. At histopathology, the most prevalent lesion in the oral cavity was superficial bacterial colonisation in 24 (40.7%) of the animals. In the oesophagus, the most prevalent lesion was oesophagitis in 11(18.6%) of the animals. In the stomach, small intestines and the colon, the most prevalent lesions were gastritis, enteritis and colitis in 22 (37.3%), 34 (58.6%) and 17 (29.3%) of animals respectively. From the computed Odds ratio, an animal with nematodiasis was 11 times more likely to have gastritis; while an animal with capillariasis was 6 times more likely to have hepatitis. However, there was no statistical relationship between enteritis and nematodiasis; colitis and nematodiasis; and fibrosis and capillariasis. The study found out that there were gross and histopathological lesions of varying prevalences in the gastrointestinal tract of free-ranging mountain gorillas.