Detection of Rift Valley Fever Virus in Aedes (Aedimorphus) durbanensis, South Africa

Carien Van Den Bergh,Alan Kemp,Peter N Thompson,Petrus Jansen Van Vuren,Estelle H Venter,Janusz T Paweska,Antonio P G Almeida,William C Wilson,Robert Swanepoel

doi:10.3390/pathogens11020125

Abstract

Rift Valley fever virus (RVFV) is a mosquito-borne, zoonotic phlebovirus-causing disease in domestic ruminants and humans in Africa, the Arabian Peninsula and some Indian Ocean islands. Outbreaks, characterized by abortion storms and a high morbidity rate in newborn animals, occur after heavy and prolonged rainfalls favouring the breeding of mosquitoes. However, the identity of the important mosquito vectors of RVFV is poorly known in most areas. Mosquitoes collected in the Ndumo area of tropical north-eastern KwaZulu-Natal (KZN), South Africa, were tested for RVFV nucleic acid using RT-PCR. The virus was detected in a single pool of unfed Aedes (Aedimorphus) durbanensis, indicating that this seasonally abundant mosquito species could serve as a vector in this area of endemic RVFV circulation. Phylogenetic analysis indicated the identified virus is closely related to two isolates from the earliest outbreaks, which occurred in central South Africa more than 60 years ago, indicating long-term endemicity in the region. Further research is required to understand the eco-epidemiology of RVFV and the vectors responsible for its circulation in the eastern tropical coastal region of southern Africa.

Highlights

Rift Valley fever virus (RVFV) [1] causes severe, intermittent and sporadic outbreaks of Rift Valley fever (RVF) in domestic ruminants in Africa, the Arabian Peninsula, Comoros, Mayotte and Madagascar [2,3,4]
This paper reports the detection, sequencing and phylogenetic analysis of RVFV from a pool of Aedes (Aedimorphus) durbanensis collected during the study
Nucleic acid was extracted from homogenized mosquito pools using the MagMAX total nucleic acid isolation kit (Applied Biosystems, Waltham, MA, USA), and extracts were screened for RVFV using real-time reverse-transcription PCR (RT-PCR) [23]

Summary

Introduction

Rift Valley fever virus (RVFV) (order Bunyavirales, family Phenuiviridae, genus Phlebovirus) [1] causes severe, intermittent and sporadic outbreaks of Rift Valley fever (RVF) in domestic ruminants in Africa, the Arabian Peninsula, Comoros, Mayotte and Madagascar [2,3,4]. This is a mosquito-borne disease usually recognized by the onset of abortion storms and high mortality rates in young ruminants, sheep [5]. The latter involved Lineage C in the eastern parts (2008–2009) and Lineage H in the central and western parts (2009–2011) of the country [8]

Methods

Results

Discussion

Conclusion