Lumpy Skin Disease (LSD) is a highly infectious viral disease which mostly affects large ruminants. Lumpy skin disease appears epidemically or sporadically. As this disease cause high economic losses, it should be taken seriously.
If we summaries the diseases in few lines before going into details, it would be “Lumpy skin disease is a viral infection of cattle. Originally found in Africa, it has also spread to countries in the Middle East, Asia, and eastern Europe. Clinical signs include fever, lacrimation, hypersalivation, and characteristic skin eruptions. Diagnosis is by histopathology, virus isolation, or PCR. Attenuated vaccines may help control outbreaks.”
Etiology
The disease caused by Lumpy Skin Disease Virus (LSDV), virus is related to that of SheepPox. Virus serotype is Neethling Strain. Neethling is the name of the farm where the virus was first isolated from cattle. LSDV is brick shape enveloped virus and has double stranded DNA. OIE has included LSD in the list of notifiable diseases of bovine. Lumpy skin disease appears epidemically or sporadically. Frequently, new foci of infection appear in areas far removed from the initial outbreak.
Fig.1
Susceptible Hosts
- Cattle (Bos Tauras and Bos indicus)
- Asian Buffalo (Bubalus bubalis)
- Impala, Giraffe, Oryx, Spring box,
High milk producing animals are more susceptible. Animals which are used for drought work are more prone to catch the infection probably due to stress of work and small skin wounds caused during load pulling which attracts vector. Calves are more susceptible to acquire the infection. Cattles of all age group and breeds are at risk. Recently infected and cured animals are immune for three months.
Things that affect/kills virus
- Highly Acidic or Alkaline pH.
- Chloroform
- Ether (20%)
- Sodium dodecyl sulfphate
- Formalin (1%)
- Sodium Hypochlorite (2 to 3%)
- Phenol (2% for 15 Minutes)
- Iodine compound (1:33 dilution)
- Quaternary ammonium compounds (0.5%)
- Sunlight
Virus Resistance
Virus is very resistant to inactivation and can survive upto 35 days in necrotic nodules, animal shelter and environment. It was found in saliva for 11 days after onset of fever, in semen for 42 days and skin nodules for 39 days.
Transmission of Virus
- Many vectors are identified so far but if we summarise in short it would be like, Any biting insect, blood sucking arthropods and flies that flies from animals to animals are capable of transmitting disease.
- Wild animal and bird movement.
- Animal to animal (rare) as animal secretes virus via salivation, nasal discharge and lacrimal discharge.
- Calf may acquire via suckling – through milk or nodules on teat and udder.
- Via natural service or Artificial Insemination from infected bull.
- Via infected syringe and needle (during treatment or vaccination).
- Animal purchase/sell or movement of migratory animals.
Morbidity
Percentage varies from 2-45 percentage. Animals giving higher outputs (milk, drought) are more prone to infection. Infected pregnant dam is more likely to give birth to calf with skin lesions.
Mortality
Less than 10 percentage.
Clinical Signs
Incubation period is 7-14 days (Experimentally) to 2 to 5 weeks (Natural Cases). Lacrimation, Nasal Discharge, Pyrexia (>=105 ºF) persist for one week, enlargement of pre-femoral and sub-scapular lymph nodes, sharp drop in milk production, depression, anorexia.
Characteristic nodular skin lesions of 1 to 5 cm in diameter are observed on head, neck, perineum, genitalia, udder and limbs. Nodules are firm, raised and mostly separated by hemorrhagic ring from normal skin.
Nodules may involve muscles if it is deep in nature. Nodules disappears with time but if it persists it remains as a hard lumps or become moist, necrotic and slough off or ulcerated. Lesions/nodules may persists for months. Corneal involvement may be observed in few cases which leads to blindness.
Chances of secondary bacterial infection and septicaemia are always there.
Pneumonia (by LSDV or secondary bacterial infection), Mastitis, Abortion (very common in acute cases of LSDV infection), aborted foetus or normal delivered calf from infected dam may have nodules on skin, infertility in female and male (due to lesion, secondary infection are common).
LSDV may invade the entire cutis and the mucosa of the GI, Respiratory and Genital tracks
Differential Diagnosis
- Pseudo lumpy skin disease/ Bovine herpes mammilitis.
- Pseudocowpox.
- Bovine papular stomatitis.
- Insect bite.
- Urticaria.
- Photosensitization.
- Dermatophilosis.
- Demodicosis.
- Besnoitiosis.
- Onchocerciasis.
Diagnosis
- Based on Clinical Signs.
- Whole blood, serum, nasal swab, oral swab, nodules, lymph nodes etc collected ante mortem or post mortem stored in 20 – 50% PBS for further investigation.
- Antigen by electron microscope.
- Antibody by Serum or Virus neutralisation test.
- Conventional and Real time PCR.
- Histopathological changes includes vasculitis and perivascular infiltration with white blood cells leading to thrombosis in vessels in dermis and subcutis.
- Immunoperoxidase monolayer assay.
- Indirect fluorescent antibody test.
- ELISA
National Institute of High Security Animal Diseases (NIHSAD), Bhopal is a laboratory for confirmatory diagnosis.
Treatment
Symptomatic Treatment. No specific treatment,
Control and Prevention
- Restriction of animal movement to and fro from virus invaded area.
- Infected premises disinfection.
- Isolation.
- Quarantine.
- Vector Control (All vectors by all means).
- Vaccination in surrounding area.
Vaccination
- Homologous live attenuated vaccine is based on attenuated Neethling strain of LSDV.
- Heterologous live attenuated vaccine is based on attenuated goat or sheep pox virus.
Mild disease like nodular formation is observed after Neethling strain vaccination.
Attenuated Gorgan goat pox vaccine provides better protection and can be a good alternative of homologous vaccine.
Areas where sheep pox and goat pox are common, cattles should not be vaccinated with goat and/or sheep pox vaccines as they may act as carrier and source of infection in sheep and goat.
HAPPY LEARNING
DR. GHANSHYAM VAGHASIYA
Blue Cross Boy 