By HAPPY MULOLANI –
THERE are various studies that have been conducted on livestock diseases by experts under the Department of Livestock and Veterinary Services in the Ministry of Agriculture and Livestock, which are worth documenting and enlightening the public on in a quest to share knowledge.
One such study was recently conducted by a Veterinary researcher Jimmy Clement Lubinga, who investigated the participation of ticks in the spread of the lumpy skin disease virus during his Doctoral study at the University of Pretoria, in South Africa However, before delving into specifics of his findings.
It is worth mentioning that Dr Lubinga obtained his Bachelor of Veterinary Medicine in 1991 and Master Veterinary Medicine in 1998 from the University of Zambia.
He worked as District Veterinary Officer and Provincial Veterinary Officer in Eastern and Northern provinces before proceeding to pursue his Doctoral degree in Veterinary Tropical Diseases at the University of Pretoria from 2010 to 2013 purely researching on lumpy skin disease and the outcome of his research is simply astonishing.
Lumpy skin disease was first diagnosed in Choma in Zambia in 1929 and then spread to other parts of Southern Africa through Bostwana into South Africa and presently, it covers the whole continent.
The epidemiology of lumpy skin transmission has been a challenging problem. While its transmission has been closely associated with flying insects, it has not been clear where the virus stays between epidemics. In this regard, Dr Lubinga’s study has confirmed the fact that ticks are also vectors for the virus and are possible reservoirs of the virus during the inter-epidemic periods.
As part of the evidence, Dr Lubinga demonstrated lumpy skin disease virus in the saliva and organs of infected ticks.
Dr Lubinga proved that ticks also act as reservoirs for the virus by showing that the virus can persist in these external parasites over long periods and through the winter when the ticks are free living and not on the animal hosts.
Dr. Lubinga further demonstrated capacity of ticks to transmit the virus in various stages of their development.
He says: “Ticks can transmit LSD mechanically if they change animal hosts within same development stage”.
He also reported transstadial transmission between developmental stages and transovarial transmission of the virus through the eggs to the larvae of the next tick generation.
These findings have been published in seven articles of international Peer-Reviewed journals. Five of these publications form his Doctoral thesis entitled: “The Roles of Rhipicephalus (Boophilus) decoloratus, Rhipicephalus appendiculatus and Amblyomma hebraeum ticks in the transmission of lumpy skin disease virus”.
A summary of his work has also been published by the farmers weekly magazine and Afrigriland in South Africa Dr Lubinga explained that this was an important discovery because ticks should be included in the plans and strategies for control of
lumpy skin disease.
This may explain, in part, the reservoir hosts for the virus “Ticks should be considered in the strategies of LSD” he explained “and with global warming, there is possibility of ticks to move to parts of the world where normally would not survive and spread the virus with them”.
Coupled with that, Dr Lubinga also said the possibility of ticks spreading over long distances is very high as they move with their host animal, such as when feeding on migrating birds.
He points out that outbreaks of LSD reduces the meat and milk quality, resulting in economic losses on livestock farmers.
“Infected cattle may become infertile due to reduced sperm quality. Abortions and reduced calving rates have been documented. It can cause permanent scarring to cattle hides, thereby reducing their quality,” Dr Lubinga said.
He further reveals that the mortality rates between 10 per cent and 40 per cent or higher can be experienced during outbreaks.
In Zambia, LSD has been reported in most cattle rearing areas.
Dr. Lubinga was hopeful that his findings will be used by the livestock owners, veterinarians and other stake holders to include tick control in their strategies to combat LSD through tick control and other recommended strategies such as vaccinations.
This study was funded by The Combating of Infectious Diseases of Livestock for International Development (CIDLID) research programme and The Department for International Biotechnology and Biological Sciences Research Council (BBRSC) in the UK.-NAIS