AbstractsBiology & Animal Science

Evaluation of vector potential of Rhipicephalus appendiculatus, Amblyomma hebraeum and Rhipicephalus decoloratus ticks for lumpy skin disease virus

by Eeva Tuppurainen

Institution: University of Helsinki
Department: Department of Veterinary Biosciences; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa; The Pirbright Institute, Pirbright, United Kingdom
Year: 2015
Keywords: virologia
Record ID: 1138426
Full text PDF: http://hdl.handle.net/10138/153942


Lumpy skin disease (LSD) is an economically important pox disease of cattle and Asian water buffalo caused by a lumpy skin disease virus (LSDV), a member of the genus Capripoxvirus. The disease occurs in Africa and the Near East, causing substantial economic losses for the whole cattle industry in affected countries. The disease is characterized by skin nodules, high fever, lymphadenopathy and loss of production of infected animals. Transmission of LSDV is known to occur mechanically by a variety of blood-feeding insects and to a lesser extent through contaminated feed and water, semen or via direct contact. The disease is classified as notifiable by the World Animal Health Organization (OIE). Currently, Finland is free of LSD. The general aim of the study was to investigate the vector capacity of common sub-Saharan tick species, Rhipicephalus appendiculatus, Amblyomma hebraeum and Rhipicephalus decoloratus for LSDV in cattle via mechanical, intra/transstadial or vertical routes. The specific aim was to investigate if mechanical transmission occurs by R. appendiculatus males and transovarial by R. decoloratus females. As many of the infected animals become viraemic without showing skin lesions, it was investigated if feeding on healthy looking skin of viraemic animals was sufficient for successful mechanical transmission. The final objective was to investigate if the virus was able to grow in vitro in Rhipicephalus spp. tick cell lines. In addition, the presence of the virus or viral DNA in ticks collected from naturally infected animals was investigated. Two animal experiments, using naïve cattle and laboratory-reared ticks were conducted at the Department of Veterinary Tropical Diseases, University of Pretoria, South Africa and samples were tested at the Pirbright Institute, United Kingdom. For the first time, transmission of LSDV (or any pox virus) by hard ticks was demonstrated to occur mechanically/intrastadially by R. appendiculatus males and vertically by R. decoloratus females. Feeding directly on skin lesions was not necessary for transmission of the virus between infected and naïve cattle. No evidence of viral replication in Rhipicephalus tick cell lines was obtained. The presence of the viral DNA was detected in Rhipicaphalus, Amblyomma and Hyalomma ticks collected during natural LSDV outbreaks in South Africa and Egypt. In 2013 - 2015 LSDV is spreading in the Near East at a scale never seen before, posing a threat to the European Union, Caucasus region, Afghanistan and Pakistan. In order to control and eradicate the disease, it is fundamental to understand the role of different arthropod vectors and their importance in the field. The presence of infected tick eggs or different instars in the environment underlines the importance of effective prophylactic tools and sufficient vaccination coverage. In addition, this study contributes to the recommendations set for the international trade of live cattle from affected countries. Capripoxviruksiin kuuluva Lumpy skin disease (LSD) on taloudellisesti…