Download African swine fever

Lumpy skin disease (LSD)
Author: Prof JAW Coetzer and Dr Eeva Tuppurainen
Adapted from: Coetzer, JAW. 2004. Lumpy skin disease, in Infectious diseases of livestock, edited by J.A.W. Coetzer & R.C.
Tustin. Oxford University Press, Cape Town, 2: 1268-1276.
Licensed under a Creative Commons Attribution license.
Introduction
(Amblyomma hebraeum) and the African blue tick
Lumpy skin disease (LSD) is a pox viral disease of
(Rhipicephalus (Boophilus) decoloratus), have recently
cattle with a major socio-economic impact. The disease
been shown to play a role in the transmission of LSD
is characterized by fever, multiple firm, circumscribed
virus.
skin
nodules,
necrotic
plaques
in
the
mucous
membranes (chiefly of the upper respiratory tract and
Skin nodules, the characteristic feature of the disease,
oral cavity), mastitis, orchitis and swelling of the
appear before or during the second rise in body
peripheral lymph nodes. The disease is caused by a
temperature, four to ten days after the initial febrile
capripox
response.
virus
of
which
the
prototype
strain,
The
nodules,
which
are
randomly
“Neethling'” was first isolated in South Africa. Clinically,
distributed and range in diameter from 10 to 20 mm,
the skin lesions of LSD closely resemble those of
involve both the skin and subcutaneous tissues and
pseudo-lumpy skin disease caused by the Allerton
sometimes even the underlying musculature. The
strain of bovid herpesvirus 2 (BHV 2).
number of nodules may range from a few to several
thousand in severely affected animals. In most cases
Very little is known about the susceptibility of wild
the nodules are particularly noticeable in the perineum
ruminants to LSDV.
and on the vulva.
Salient features of LSD
In severely acutely affected animals the ventral parts of
Available evidence suggests that there is only one
the body, for example the dewlap and the legs may be
immunological
slightly oedematous one to two days before the
type
of
LSDV.
Cross-protection
between LSDV and sheep- or goatpox viruses has
appearance of the nodules.
been exploited by the use of sheeppox virus for the
immunization of cattle against LSD in Kenya and in the
Nodular skin lesions may extend into underlying tissue
Middle East. Lumpy skin disease virus is remarkably
such as tendons and tendon sheaths resulting in
stable.
lameness in one or more legs. Most affected animals
have multifocal, roughly circular, necrotic areas on the
The mode of transmission of LSD has not been
muzzle and in the respiratory tract (nasal cavity, larynx,
established fully, although circumstantial evidence
trachea and bronchi), and buccal cavity. These lesions
suggests that biting insects play a role in the
may also be present in the forestomachs, abomasum,
dissemination of infection. The three common African
uterus, vagina, teats, udder, and testes. Acute orchitis
hard
may progress to fibrosis and atrophy of the testes
tick
species,
(Rhipicephalus
namely,
appendiculatus),
the
the
brown
tick
bont
tick
resulting in temporary or permanent infertility or more
Lumpy skin disease in cattle is usually more prevalent
rarely, sterility.
during wet summer and autumn months following an
increase in populations of biting flies and tick vectors.
Nodules may form in the skin of the udder and teats,
and when the parenchyma of the udder is involved, as
Prevention and control – how and why
it frequently is, the gland is swollen and tender as a
A presumptive diagnosis of the disease can be made
result of mastitis. Secondary bacterial mastitis may be
on the clinical signs. The clinical signs and lesions in
severe and complicate the udder lesions.
mild cases of LSD can easily be confused with pseudolumpy skin disease (BHV-2 infection). Generally, BHV-
Although LSD does not have a high mortality rate
2 infection causes more superficial skin lesions, has a
(usually less than 10 per cent), it is of economic
shorter course and is a milder disease than LSD. The
importance because of permanent damage to hides,
diagnosis can be confirmed within a few hours of
the prolonged debilitating effect it may have on
receipt
severely affected animals with consequent losses
microscopic demonstration of virus in negatively-
resulting from reduced weight gain, temporary or
stained preparations of biopsy specimens taken from
permanent cessation of milk production as a result of
affected
mastitis, temporary or permanent infertility or even
Immunohistochemical
sterility in bulls as a consequence of orchitis, and
immunoperoxidase staining of tissue sections, can also
abortion in approximately 10 per cent of pregnant
be used to demonstrate the virus in acute and chronic
cows.
skin lesions.
Immunity after recovery from natural infection is life-
Several conventional and real-time polymerase chain
long in most cattle.
reaction (PCR) methods are available for the detection
of
specimens
skin
by
or
transmission
mucous
methods,
electron
membranes.
for
example
of LSD virus.
Where does LSD occur?
Periodic epidemics occur in most African countries,
The interpretation of serological results may sometimes
particularly in those of the sub-Saharan region.
be difficult due to low antibody titres in vaccinated
Currently there are only four countries in Africa
animals and some individuals following mild infection.
(Morocco, Tunisia, Algeria and Libya) that has not
The virus neutralization test is considered to be the
reported LSD.
most reliable serological test. Several ELISA’s for the
detection of capripoxvirus antigen or antibody have
Since 2000, LSD outbreaks have been reported across
been developed but currently none of them is
the Middle East (Israel, West Bank, Lebanon, Jordan,
commercially available.
Turkey and Iraq) and it is highly likely that the disease
will become endemic at least in parts of the Region. An
Control by quarantine and movement control is
incursion of LSD was reported for the first time in
generally not very effective. In endemic areas control is
Turkey and Iraq in 2013, indicating that the disease
essentially
has a potential for further spread to the European
Susceptible adult cattle should be vaccinated annually
Union and Caucasus region, as well as to Asia.
to ensure adequate protection against LSD.
born
What triggers an outbreak of LSD?
to
confined
susceptible
to
cows
immunoprophylaxis.
are
Calves
themselves
very
susceptible and should be vaccinated as soon as
possible in the face of an outbreak.
The World Organization for Animal Health (OIE)
categorizes LSD as a notifiable disease and standards
are set for safe international trade of live animals and
animal products.
Find out more
The CPD module on LSD describes its history,
aetiology and epidemiology, how to recognise it and
confirms the diagnosis, its potential for transboundary
spread and the challenges to control the disease.