WildLife Group of the SAVA
Lumpy Skin Disease of Springbok
Dr R D Last – BVSc ; M . Med . Vet ( Pathology ) Specialist Veterinary Pathologist
Introduction
Lumpy skin disease ( LSD ) is a well-known , presumed insect transmitted , capripox viral infection of cattle , endemic to most African countries , although since 2012 there has been rapid spread through the Middle East , Southeast Europe , the Balkans , Caucasus , Russia and Kazakhstan . Clinical lumpy skin disease has now been confirmed in springbok in South Africa , and suspected in springbok from Namibia .
A disease suspected to be LSD has also been described in water Buffalo ( Egypt ), Arabian oryx ( Saudi Arabia ) and oryx ( South African ), while giraffe and Impala are highly susceptible to experimental infection . Natural infection of African buffalo remains controversial and current available evidence suggests that they are probably not / or only slightly susceptible .
The Virus
LSD is caused by lumpy skin disease virus ( LSDV ), which is a virus from the family Poxviridae , genus Capripoxvirus . Sheeppox virus and Goatpox virus are the other two species in this genus and closely related to LSDV . Currently only one immunological type of LSDV is thought to occur in natural disease , which shows complete cross reaction with the prototype “ Neethling ” strain .
LSDV is remarkably stable , surviving for long periods at ambient temperature especially in dried scabs , desiccated crusts , necrotic skin nodules and air-dried hides .
Pathogenesis
The primary mode of transmission of the virus is believed to be via arthropod vectors , although this has not yet been fully established . The virus has been recovered from biting flies ( Stomoxys spp and Musca confiscate ) and mechanical transmission has been demonstrated with Aedes egypti mosquitoes . Three common African tick species namely brown tick ( Rhipicephalus appendiculatis ), bont tick ( Amblyomma hebraeum ) and African blue tick ( Rhipicephalus ( Boophilus ) decolaratus ) were experimentally able to transmit the virus mechanically ( brown tick , bont tick ) as well as trans-ovarially ( blue tick ). Bont ticks overwinter as nymphal stages while African blue ticks overwinter in gravid females and eggs . Therefore , such a scenario might in part explain how lumpy skin disease virus survives between disease outbreaks . Skin nodules , crusts and scabs contain extremely high levels of LSDV and are deemed to be the primary source of virus material for mechanical transmission by arthropods .
Direct animal to animal transmission through close contact plays a minor , if any , role in virus transmission and such transmission is believed to be highly inefficient . There have however , been reports of transmission occurring when common drinking troughs were used indicating that saliva may contribute to the spread of the disease . Disease transmission to suckling calves via infected milk has been reported in cattle . Virus has also been isolated from semen in cattle , but venerial transmission of the disease is not known to occur . It is unknown if
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