Abstract:
Lumpy skin disease is a debilitating cattle disease caused by the lumpy skin
disease virus (LSDV), belonging to the genus Capripoxvirus. Epidemics of the disease
usually occur in summer, when insect activity is high. Limited information is available on
how LSDV persists during inter-epidemic periods. Transmission of LSDV by mosquitoes
such as Aedes aegypti has been shown to be mechanical, there is no carrier state in cattle
and the role of wildlife in the epidemiology of the disease seems to be of minor importance.
Recent studies in ticks have shown transstadial persistence of LSDV in Rhipicephalus
appendiculatus and Amblyomma hebraeum as well as transovarial persistence of
the virus in Rhipicephalus decoloratus, R. appendiculatus and A. hebraeum. The overwintering
of ticks off the host as part of their life cycles is well known: A. hebraeum and
R. appendiculatus over-winter, for example, on the ground as engorged nymphs/unfed
(emergent) adults while R. decoloratus over-winters on the ground as engorged females. In
this study, transstadial and transovarial persistence of LSDV from experimentally infected
A. hebraeum nymphs and R. decoloratus females after exposure to cold temperatures of
5 C at night and 20 C during the day for 2 months was reported. This observation
suggests possible over-wintering of the virus in these tick species.
