Rift Valley fever outbreaks: Possible implication of Hyalomma truncatum (Acari: Ixodidae)

Abstract

Rift Valley fever (RVF) is a viral zoonosis that primarily affects livestock. However, the virus can also infect humans and may even cause human fatalities. Although the vast majority of human infections result from direct or indirect contact with the blood or organs of infected animals, human infections have also resulted from the bites of infected Aedes mosquitoes. Due to the increasing importance of zoonotic diseases including RFV to global health, there is need for in-depth knowledge on the transmission of RFV viruses. We postulate that some hard ticks might be involved in the transmission of Rift Valley fever virus between animals in nature. This can partially be explained by the biology of ticks. Firstly, ticks spend long periods feeding on the host. Secondly, disease-bearing ticks may survive long periods of desiccation and an infected fully fed female tick continue to harbour RVF virus post-oviposition. Current geographical distribution of Hyalomm truncatum (Acari: Ixodidae) appears to show correlation with incidence of RVF. Future interdisciplinary research focusing on Rift Valley fever molecular epidemiology and tick chemical ecology, will certainly establish the role that H. truncatum and other ticks play in the spread of the virus in nature, and consequently contributing to the development of effective Rift Valley fever management strategies.