AGRICULTURAL
Lumpy Skin Disease Virus
Lumpy skin disease ( LSD ) is a disease that is endemic to many African countries and causes debilitation of cattle and economic loss wherever it occurs . 1
� By Dr . Barry van Houten Zoetis South Africa , Technical Manager : Ruminants
HISTORY AND RECENT OUTBREAKS The disease is caused by the Lumpy Skin Disease Virus ( LSDV ), from the Capripoxvirus genus and Poxviridae family , and was confined to Sub-Saharan Africa and Madagascar until the mid-1980 ’ s . 2 In 1989 , an outbreak in Israel was eradicated through a slaughter and vaccination scheme . 2 Since then , the disease has spread rapidly into the Middle East , Turkey , Azerbaijan and the Russian Federation , with outbreaks occurring between 2012 and 2015 . 3 , 6 Further outbreaks of LSDV occurred throughout Eastern Europe in 2016 , including countries like Greece , Serbia , Macedonia , Montenegro and Bulgaria ; resulting in these countries implementing vaccination programmes to prevent further spread of the disease . 7 A major reason for the increase in outbreaks in these areas include the breakdown of veterinary services during conflict situations with the resulting uncontrolled movement of animals . 3
Nodules over the animal ’ s body . Source : Dr . Leratoli
TRANSMISSION The incidence of LSDV is higher during wet and warm conditions , due to the increase of insect vectors during this time . LSDV is usually transmitted through biting insects including mosquitoes in the Aedes and Culex genera , biting flies , and various tick species including ; Rhipicephalus decoloratus ( blue tick ), R . appendiculatus ( brown ear tick ) and Amblyomma hebraeum ( spotted tick ). 1 , 2 Transmission of LSDV via direct contact is poorly understood and was said to be ineffective . However , animals can be experimentally infected when inno culated with material from nodules , or being exposed to saliva-infected feed and water . 2 LSDV can be spread in bull semen following infection , and it has recently been shown that experimental seminal transmission of LSDV can occur in cattle . 4
CLINICAL SIGNS AND ECONOMIC IMPORTANCE Clinical signs can range from apparent to severe , depending on the type of host ( breed ), route of innoculation , dose and age . 2 Bos Indicus cattle are generally more resistant to LSDV than Bos Taurus animals . 2 The initial signs of LSDV is fever , followed by the development of nodules on the skin and mucous membranes over the next few days . 2 Skin nodules vary in size ( 1 – 7 cm ) and occur through the full thickness of the skin . 2 These nodules can then form a central area of necrosis called a “ sit-fast ” that separates from the skin and can become complicated with secondary bacterial infections . 2 These
areas then form a hard crust to allow the wounds to heal . Superficial lymph nodes become enlarged and mucous membranes usually show flat , ulcerative lesions . 2 Ulcerative lesions also occur on the teats and udder , which result in the area being swollen and tender . 3
Morbidity rates can vary dramatically depending on the breed , age , immune status and presence of insect vectors . 2 Previous outbreaks in RSA have recorded morbidity rates of around 1-20 %, with some instances being higher . 2 Mortality rates are usually low ( 1-3 %), but have been higher in some instances . 1
The major problem with LSDV outbreaks are the economic implications for the producer . These include : 1 , 2
• Emaciation and poor growth
• Damage to carcasses
• Damage to hides
• Mastitis and reduced milk production
• Lameness
• Abortion
• Sterility in bulls ( loss of genetic potential )
• Pneumonia and abscessation
• Treatment , culling and replacement costs .
PREVENTION In endemic countries like South Africa , vaccination against Lumpy Skin Disease with live , attenuated vaccines are essential in controlling the spread of the disease and is the only effective method of controlling the disease in endemic areas . Outbreaks are more common during the wet / warm season , when insect vectors are present in large numbers , and vaccination should be performed before this time to protect against LSDV and its devastating economic implications . 3
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References available on request . Reference number : 36 / 1702
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SENWES SCENARIO | WINTER 2018