Risk factors for Rift Valley fever virus seropositivity in one-humped camels (Camelus dromedarius) and pastoralist knowledge and practices in Northern Nigeria

Rift Valley fever (RVF) is a complex emerging arboviral hemorrhagic disease that causes significant illness in animals and humans. Camel trade across the land borders between Nigeria and the Niger Republic occurs frequently and poses a significant risk for RVF transmission to pastoralists and traders. We carried a crosssectional study between November 2016 and April 2017 in two northern States (Katsina and Jigawa) known for camel trade in Nigeria to investigate the seroprevalence and potential risk factors for RVFV occurrence. We collected 720 sera and administered questionnaire to pastoralists. We used the competitive enzyme-linked immunosorbent assay (c-ELISA) to determine the previous exposure to RVFV infection. We retrieved environmental information from public data sources that might explain RVFV seropositivity at the LGA level. To asses potential risk factors,we categorized LGAs with RVFV as 1 and those without a case 0. We fitted a logistic model to the data and estimated odds ratios and 95% confidence intervals. An overall 19.9% prevalence was reported among camel herd-the highest seropositivity (33.3%) was recorded in SuleTankarkar LGA. In the multivariable model, only rain-fed croplands was significantly associated with RVFV antibodies occurrence p = 0.048 (OR = 0.87, 95% CI: 0.76-0.99). Only a minority of the respondents, 19.3% (n = 17/88), knew that RVF is zoonotic. Separation of healthy animals from the infected animals was carried out by 53.4% (47/88) pastoralists while 59.1% (52/88) pastoralists still use ethnoveterinary practices to control or mitigate disease outbreaks. Our study demonstrates the presence of RVFV antibodies among camel in Nigeria and the associated risk factors. These findings highlight the need for enhancing surveillance and control efforts and the public health education of camel pastoralists. Further investigation to unravel the zoonotic transmission potential to pastoralists and other animal species is pertinent.

Automated summary

The study reveals the presence of RVFV antibodies among camels in Nigeria, with rain-fed croplands being a significant risk factor. Only a minority of respondents knew that RVF is a zoonotic disease, and most pastoralists still rely on ethnoveterinary practices for disease control.