Serological evidence of Rift Valley fever infection and risk factors among one-humped camels (Camelus dromedarius) in Northern Nigeria
Authors: Musa Adamu Andrew , Ayo Yila Simon , Lushakyaa Allam , Anthony Sackey , Bida Alhaji Nma , Sikiti Garba Bello , Salamatu Mambula-Machunga , Daniel Nafarnda Wesley , Idoko Idoko Sunday , Emmanuel Balogun Oluwadare , Adewale Owolodun Olajide , Adamu Dzikwi Asabe 
Published: January 2020

Background

Rift Valley fever (RVF) is a zoonotic disease that has become emerging and re-emerging in some regions of the world, infecting livestock and humans. One-humped camels are important economic livestock species in Africa used for traction, transportation, and food. Regional and international trade has continued to increase the risk of this disease, spreading widely and causing severe economic and public health catastrophes in affected regions. In spite of these risks, there is a dearth of information about the status of RVF in camels in Nigeria. This study was carried out to determine the prevalence of the RVF virus in one-humped camels in Nigeria and identify the risk factors associated with the disease.

Methods

A cross-sectional study with simple random sampling was carried out in seven local government areas of Jigawa and Katsina States. The sera from camels were tested for anti-RVFV IgG. Camel owners were administered a structured questionnaire to ascertain their knowledge, attitude, and practice.

Results

An overall prevalence of 19.9% (95% CI; 17.07-22.90) was recorded. Based on age groups, the highest prevalence of 20.9% (95% CI; 17.00-25.31) was obtained among older camels (6-10 years), while female camels recorded a high prevalence of 20.4% (95%CI; 15.71-25.80). Sule Tankar-kar recorded the highest prevalence with 33% (95%CI; 1.31-4.72, p= 0.007) and OR 2.47 in Jigawa State while Mai’adua had 24.7% (95%CI; 0.97-2.73, p=0.030) with OR 1.62 in Katsina State respectively. From the risk map, local government areas bordering Niger Republic were at a high risk of RVF. Only high rainfall was not significantly linked with RVF occurrence among nomadic camel pastoralists (95%CI 0.93-5.20; p=0.070).

Conclusion

There is a need for the country to have quarantine units across borders for screening animals coming from neighbouring countries for transboundary infectious diseases such as RVF.

Author Summary

Rift Valley fever is a viral haemorrhagic fever that affects animals and humans with high mortality. Recently there has been increased demand in camel meat and products for food and therapeutic purposes. Climate change, coupled with insecurity in the Sahel, has had a significant impact on transhumance activities where camels and their owners move to different countries in search of pasture for their animals. Though Nigeria has not reported an outbreak of Rift Valley fever despite serological evidence in various animal species, there is a need to assess RVF in camels, which is a critical animal species, involved in transhumance with the potential of introducing transboundary diseases into new areas. The study assessed the presence of antibodies in camels, identified risk factors associated with the disease in camels and areas at risk for the disease. Our study found a seroprevalence of 19.9% in camels in two northern states of Nigeria, which shares a boundary with the Niger Republic that recently reported an outbreak. Our findings suggest that areas in proximity to Niger Republic are at a high risk to the disease and camels belonging to transhumance pastoralists are highly likely to contract Rift Valley fever since they are exposed to various ecological and environmental factors that precipitate the disease.