LUMPY SKIN DISEASE - LSD

L           Lumpy skin disease is an infectious, eruptive, occasionally fatal disease of cattle characterized by 

               nodules on skin and other parts of body.

·                 LSD is a vector borne pox disease of cattle and water buffaloes.

ETIOLOGY:

·       Virus: Lumpy skin disease virus(LSDV)

·       Genus: Capripox virus

·       Family: Poxviridae

·       The prototype strain is known as Neethling poxvirus

·       Sheep poxvirus and goat poxvirus are the other two viruses in the genus capripoxvirus.

RESISTANCE TO PHYSICAL AND CHEMICAL ACTION:

·       Temperature:

·       Susceptible to 55˚C for 2 hours, 60˚C for 30 minutes

·       Can be removed from skin nodules kept at -80˚C for 10 years and infected tissue culture fluid stored at 4˚C for 6 months.

·       pH:

·       Susceptible to acid or alkaline pH

·       No significant reduction in titre when held at pH 6.6-8.6 for 5 days at 37˚C.

·       Disinfectants:

·       20% ether

·       Chloroform

·       1% formalin

·       Sodium dodecyl sulphate

·       2% phenol – 15 minutes

·       2-3% sodium hypochlorite

·       Iodine compounds (1:33 dilution)

·       2% virkon

·       0.5% quaternary ammonium compounds

·       Survival:

·       LSDV is remarkably stable, surviving for long periods in dried scabs

·       Very resistant to inactivation

·       Survives in necrotic skin nodules for up to 33 days or longer

·       In desiccated crusts for 35 days

·       In air dried hides for at least 18 days

·       The virus is susceptible to sunlight and detergents containing lipid solvents

·       In dark environmental conditions (contaminated animal shed), it can persists for months.

EPIDEMIOLOGY:

·       LSD appears epidemically or sporadically.

·       Endemic in South Africa

·       LSD is common during wet summer and winter months

·       Morbidity: 10-20%

·       Mortality:1-5%

HOSTS:

·       LSDV is highly host specific and causes disease only in cattle(Bos indicus, Bos Taurus) water buffalo(Bubalus bubalis)

·       Holstein Friesian or crossbred cattle exhibit higher mortality and morbidity compared to zebu cattle

·       LSDV is not zoonotic

TRANSMISSION:

·       The principal means of transmission is by arthropod vector.

·       Mosquitoes: Culex mirificens, Aedes natrionus

·       Biting flies: Stomaxys calcitrans, Biomyia fasciata

·       Male ticks: Riphicephalus appendiculatus,

Amblyomma hebraeum

·       Direct contact with excretions of affected animals

·       Calf gets infected by suckling

·       Iatrogenic intra- or inter- herd transmission may occur via contaminated needles during vaccination or injection if needles between animals are not changed.

SOURCES OF VIRUS:

·       LSDV can be isolated from blood, semen, saliva, nasal and ocular discharge

·       High amount of virus remain for 35 days in skin nodules,scab, crusts

·       There has been one reported of placental transmission of LSD

·       LSD doesn’t cause chronic disease

·       It doesn’t exhibit latency.

ECONOMIC IMPACT:

·       Mastitis and loss of milk production

·       Emaciation

·       Abortion

·       Damaged carcasses

·       Damaged hides

·       All leads to loss of income

PATHOGENESIS:

·       Incubation period: 2-4 weeks

                               

Virus entry   ------ Arthropod bite, semen, contact with nodules,saliva, secretions ---

Initial multiplication in the localized area (epidermis/dermis)-------Blood/lymph ----- Local/regional 

lymphnode- infects macrophages- enlargement of lymphnodes -----Primary viremia/ macrophage 

associated viremia  in 7-21  days post infection ------Further replication – Bone marrow, lung, liver, 

spleen, kidney ----Vascular endothelium --Vasculitis,thrombosis,infarction ----   Edema --Inflammatory 

 nodules--  Circumscribed,firm,raised nodules.

 CLINICAL SIGNS:

·       Initially Fever may exceed 41˚C

·       Marked reduction in milk yield

·       Depression, anorexia, emaciation

·       Enlarged superficial lymph nodes

·       Rhinitis

·       Conjunctivitis

·       Excessive salivation

·       Cutaneous nodules (2-5 cm in diameter) develop on head, neck, limbs, udder, genitalia and perineum within 48 hours of fever.

·       Large nodules become necrotic and fibrotic and persists for several months- “Sit fasts”

·       Myiasis of nodules may occur

·       Small nodules resolve spontaneously without consequences

·       Vesicles, erosions, ulcers develop in the mucous membranes of the mouth and alimentary tract, trachea and lungs

·       Limbs and ventral parts of body become edematous causing animal reluctant to move.( sometimes without skin lesions edema in the forelimbs or hind limbs or the ventral abdomen are obvious)

·       Limb edema and brisket edema in some cases.

·       Bulls may be permanently or temporarily infertile

·       Abortion

·       Recovery from severe is low due to :

·       Emaciation

·       Secondary pneumonia ( with or without nasal discharge)

·       Mastitis

·       Necrotic skin plugs

·       Myiasis- deep holes in hides

DIAGNOSIS:

·       Clinical signs

·       Virus detection:

·       PCR- least expensive and quickest method to detect LSDV

·       Electron microscopy

·       IFAT

·       Antibody detection:

·       Virus neutralization test: Gold standard test for detection of antibodies raised against capri poxviruses

·       Western blot: highly sensitive and specific but expensive and difficult to perform

·       Capri poxvirus antibody enzyme-linked immunosorbent assay- commercial kit

·       Preferred sample of choice for diagnosis:

·       Skin nodules, scab, crust

·       Saliva/ nasal swabs

·       EDTA blood for PCR

·       Whole blood for serum samples

·       Virus should be transported in virus transport media- 50% glycerol saline, kept on ice tanks

·       For storage of virus, store at -20˚C.

·       Histopathology of nodule: Eosinophilic intracytoplasmic inclusions

·       Postmortem lesions:

·       Lesions are found throughout the entire digestive and respiratory tracts and on the surface of almost any internal organs.

TREATMENT:

·       LSD is mostly a self-limiting disease

·       No specific treatment

·       Symptomatic treatment can be given

·       Antibiotics to control secondary bacterial infection( Enrofloxacin, Streptopenicilin ,Ceftiofur can be used)

·       If edema persist administer Furosemide 2 to 4 mg per kg bwt IM

·       Anti inflammatory like Flunixin meglumine can be given @ 1.1 to 2.2 mg per Kg Iv to alleviate pain and respiratory conditions .

·       Supportive therapy with B Complex injectable and in severe affections Vitamin ADE can be added.

·        Management of wound by application of Povidone iodine ointment or Gamma Benzene Hexachloride ointment as fly repellent. Topical sprays can be applied to prevent myiasis.

·       Administration of Ivermectin subcutaneously in case of myiasis .

·       Young calves affected should be treated with most care and fluid therapy.

·       Homeopathic Remedies are found to be very effective in treatment of skin lesions.( Attached Seperatley)

· Ethnovet preparations can be applied on skin leisons

PREVENTION AND CONTROL:

·       The first step in preventing the spread of disease is the isolation of affected animal

·       Restrict the movement of affected animal to unaffected areas.

·       Proper disposal of dead animals- incineration

·       Restrict trading animals from infected countries

·       Clean and disinfect the infected premises with disinfectants

·       Surveillance measures to detect LSD for a distance of 20 km from infected area

·       Vector control

ETHOVETERINARY TREATMENT:

·       For tropical treatment of wound:

Ingredients	Quantity
Kuppaimeni leaves(Acalypha indica)	One  hand full
Neem leaves	One hand full
Thulasi (Holy basil)	One hand full
Turmeric powder	10 g
Marudhani leaves(henna)	One hand full
Neem oil	As needed

·       Grind the above ingredients and mix it with neem  oil

·       Apply it on the wounds(nodules) after cleaning it.

VACCINATION:

·       Homologues LSDV live attenuated vaccine- Neethling LSD strain

·       Heterogenous sheep pox or goat pox live attenuated vaccine strain.

·       Local reaction may sometimes develop at the site of vaccination like fever, reduction in milk yield.

DIFFERENTIAL DIAGNOSIS:

Disease	Differential diagnosis
Pseudo lumpy skin disease/ Bovine herpes mammilitis	Dermal lesion are more superficial Course of the disease is shorter and less severe
Insect bites, urticarial, photosensitization	Dermal lesion are more superficial Course of the disease is shorter and less severe
Pseudocowpox (parapoxvirus)	Lesions occur only inteat and udder
Dermatophilosis	Early ringworm lesions More superficial Clearly different Non-ulcerative surface structure of lesion
Demodicosis	Dermal lesions are predominantly over withers, neck,back, flanks, often with alopecia present Skin scrappings
Bovine popular stomatitis	Lesions occur only in the mucous membranes of the mouth
Besnoitiosis	Lesions in scleral conjunctiva Dermal lesions exhibit alopecia Thick and wrinkled skin
Onchocerciasis	Dermal lesions most likely at ventral midline