Rift Valley fever: Real or perceived threat for Zambia?

George Dautu,Polly Roy,Aaron S Mweene,Antony Musoke,Calvin Sindato,Phelix A.O Majiwa,Robert Noad,Janusz Paweska,Kenny L Samui

doi:10.4102/ojvr.v79i2.466

Abstract

Rift Valley fever (RVF) in Zambia was first reported in 1974 during an epizootic of cattle and sheep that occurred in parts of Central, Southern and Copperbelt Provinces. In 1990, the disease was documented in nine districts of the provinces of Zambia. In the last two decades, there have been no reports of RVF. This long period without reported clinical disease raises questions as to whether RVF is a current or just a perceived threat. To address this question, World Organisation for Animal Health (OIE) disease occurrence data on RVF for the period 2005−2010 in the Southern Africa Development Community (SADC) was analysed. From the analysis, it was evident that most countries that share a common border with Zambia had reported at least one occurrence of the disease during the period under review. Due to the absence of natural physical barriers between Zambia and most of her neighbours, informal livestock trade and movements is a ubiquitous reality. Analysis of the rainfall patterns also showed that Zambia received rains sufficient to support a mosquito population large enough for high risk of RVF transmission. The evidence of disease occurrence in nearby countries coupled with animal movement, and environmental risk suggests that RVF is a serious threat to Zambia. In conclusion, the current occurrence of RVF in Zambia is unclear, but there are sufficient indications that the magnitude of the circulating infection is such that capacity building in disease surveillance and courses on recognition of the disease for field staff is recommended. Given the zoonotic potential of RVF, these measures are also a prerequisite for accurate assessment of the disease burden in humans.

Highlights

Rift Valley fever (RVF) is an economically important, emerging arthropod-borne viral disease of both livestock and man
This review demonstrates that Rift Valley fever virus (RVFV) is a threat to Zambia as the environmental risk factors conducive for its propagation are widely distributed in most livestock producing areas
Despite the threat posed by RVF in Zambia, little research has so far been done

Summary

Introduction

Rift Valley fever (RVF) is an economically important, emerging arthropod-borne viral disease of both livestock and man. Rift Valley fever (RVF) in Zambia was first reported in 1974 during an epizootic of cattle and sheep that occurred in parts of Central, Southern and Copperbelt Provinces. These transovarially infected mosquitoes feed on susceptible livestock (e.g. sheep and cattle) that rapidly http://www.ojvr.org develop high-titer viremias and signs of clinical disease.

Results

Conclusion