Cross-Reaction or Co-Infection? Serological Discrimination of Antibodies Directed against Dugbe and Crimean-Congo Hemorrhagic Fever Orthonairovirus in Nigerian Cattle.

Dugbe orthonairovirus (DUGV) and Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) are tick-borne arboviruses within the order Bunyavirales. Both viruses are endemic in several African countries and can induce mild (DUGV, BSL 3) or fatal (CCHFV, BSL 4) disease in humans. Ruminants play a major role in their natural transmission cycle. Therefore, they are considered as suitable indicator animals for serological monitoring studies to assess the risk for human infections. Although both viruses do not actually belong to the same serogroup, cross-reactivities have already been reported earlier-hence, the correct serological discrimination of DUGV and CCHFV antibodies is crucial. In this study, 300 Nigerian cattle sera (150 CCHFV seropositive and seronegative samples, respectively) were screened for DUGV antibodies via N protein-based ELISA, indirect immunofluorescence (iIFA) and neutralization assays. Whereas no correlation between the CCHFV antibody status and DUGV seroprevalence data could be demonstrated with a newly established DUGV ELISA, significant cross-reactivities were observed in an immunofluorescence assay. Moreover, DUGV seropositive samples did also cross-react in a species-adapted commercial CCHFV iIFA. Therefore, ELISAs seem to be able to reliably differentiate between DUGV and CCHFV antibodies and should preferentially be used for monitoring studies. Positive iIFA results should always be confirmed by ELISAs.

Aflatoxicosis in African greater cane rats (Thryonomys swinderianus).

AIM: Aflatoxicosis is a widespread problem in captive animals fed on stored food and has been reported in various animals both domestic and wild. This report documents the clinicopathologic, microbial diagnostic findings and therapeutic regime for a study on the presentation, management, and outcome of aflatoxicosis in greater cane rats. MATERIALS AND METHODS: A total of 65 greater cane rats suspected to be exposed to the toxin were examined clinically along with their environment. Feed samples, recently deceased carcasses and some moribund carcasses were collected for the study. Carcasses were subjected to gross and histopathologic investigations while feed and organs were subjected to microbiological investigations. RESULTS: Gross lesions included hepatic lipidosis with ecchymotic hemorrhages, distended gallbladder, and renomegaly with ecchymosis among others. Histopathology revealed loss of hepatocellular architecture with massive centrilobular hepatocyte necrosis and diffuse steatotic damage characterized by macrovacuoles. Other histologic findings included pulmonary congestion, moderate renal tubular degeneration, and necrosis of epithelial tubular cells. Aspergillus flavus was isolated from the feed and ingesta. Total aflatoxin detected in feed sample was found to be over 400 ppm. Klebsiella species, Staphylococcus species, and Bacillus species were isolated from the liver and intestinal content. Management was attempted using Fungizal® (Avico, Jordan) (which contains Thymol, benzoic acid, sorbic acid, and kaolin) and Orego-Stim® (Saife, USA) (which contains carvacrol and thymol) which were instituted in feed and Superliv® (Ayurvet, India) (polyherbal) liquid was instituted in water for 5 days at manufacturers' dosage. All clinical signs disappeared, and no more deaths were recorded following management. CONCLUSION: This report concludes that aflatoxicosis causes severe mortality in greater cane rats and can be prevented and managed successfully.