lampi virus – Lumpi skin disease (LSD) is a viral disease affecting cattle and water buffaloes. It is caused by the lumpi skin disease virus (LSDV) and characterized by nodules on the skin and high fever. LSD is creating havoc among cattle farmers in India currently.
In this comprehensive guide, we will cover all aspects of this cattle disease – cause, transmission, symptoms, treatment, prevention, and control measures.
What is Lampi virus ?
Lumpi skin disease (LSD) (Lampi virus) is an infectious viral disease of cattle and buffaloes transmitted by blood-feeding insects like mosquitoes and flies. It is caused by the lumpi skin disease virus (LSDV) which belongs to the Capripoxvirus genus.
LSD was first detected in Zambia in 1929 and has now spread to many parts of Africa, Middle East, and Asia. The disease is endemic in African and Middle Eastern countries. In India, LSD was first reported in Odisha in 2019, and since then outbreaks are being frequently reported from several states.
Causative Agent of Lampi virus
Lumpi skin disease is caused by the lumpi skin disease virus (LSDV). Key facts about LSDV:
- It is a double-stranded DNA virus of the Capripoxvirus genus under the Poxviridae family.
- Other viruses of the Capripoxvirus genus are sheeppox virus and goatpox virus which can also occasionally infect cattle.
- LSDV is closely related to the sheeppox and goatpox viruses but is host-specific to cattle and buffaloes.
- It is structurally a large brick-shaped virus measuring around 260-300 nm.
- The virus is stable over a wide pH range of 4-10 and remains viable for long periods in the environment.
- LSDV isolates have over 95% genetic similarity indicating very low antigenic variation among strains.
Transmission of Lampi virus
Lampi virus spreads through arthropod vectors and direct contact with infected cattle. The key means of transmission are:
- Blood-feeding insects – Mosquitoes, flies, ticks act as mechanical vectors. They transfer virus on their mouthparts while biting between infected and healthy animals.
- Direct contact – Nose to nose contact or sharing of infected food/water leads to transmission through secretions/excretions of infected cattle.
- Fomites – Indirect contact through virus-contaminated objects like farm equipment, clothes, shoes etc can also spread LSDV.
- Ingestion – Drinking raw contaminated milk from infected cattle can spread the virus to calves and humans.
- Inhalation – Aerosols from infected cattle during close confinement like transport can spread LSDV.
- Iatrogenic means – Reusing needles, syringes leads to transmission between cattle during vaccination or medication.
Symptoms of Lumpi Skin Disease
The incubation period of LSD ranges from 4-14 days. After infection, the symptoms appear as:
- Nodules on skin – The hallmark sign of LSD is firm round nodules 2-5 cm diameter on the skin around neck, genitals, udder, perineum. Nodules may develop scabs.
- Fever – Infected cattle suffer from high fever over 104°F which may last for a week.
- Lymphadenitis – Swelling and inflammation of lymph nodes occur 1-2 weeks after infection.
- Nasal/Ocular discharge – Watery discharge may be seen from eyes and nose. Erosions and crusts can form on muzzle.
- Reduced milk yield – Milk production in lactating cows and buffaloes can drop by 40-50%.
- Loss of appetite – Infected cattle often lose appetite and appear lethargic.
- Abortion – Pregnant cattle may suffer from abortion when infected in early pregnancy.
- Infertility – Infection can lead to temporary infertility in bulls and cows.
- Lameness – Lesions in the hoof region can cause pain and lameness.
- Mortality – Death rates in untreated acute cases can reach 10-20%.
Diagnosis of Lumpi Skin Disease
LSD can be diagnosed based on clinical symptoms, lab tests, and differential diagnosis. Key diagnostic methods include:
- Visual examination – Presence of characteristic skin nodules aids in tentative diagnosis.
- PCR tests – Viral DNA can be detected in tissue samples, blood, secretions using PCR tests.
- ELISA – Presence of LSDV-specific antibodies in sera can be detected using ELISA.
- Histopathology – Microscopic examination of skin nodules shows eosinophilic intracytoplasmic inclusion bodies in infected cells.
- Electron microscopy – The typical brick-shaped LSDV particles in scab extracts confirm the diagnosis.
- Virus isolation – LSDV can be isolated from scabs and nodular fluid in cell cultures like lamb testis or Vero cells.
- Differential diagnosis – Conditions like dermatophilosis, pseudocowpox, bovine herpes mammillitis need to be ruled out.
Treatment of Lumpi Skin Disease
There is no specific treatment for LSD. Supportive therapy can help relieve symptoms:
- NSAIDs – To control fever and inflammation, non-steroidal anti-inflammatory drugs like Meloxicam can be administered.
- Antibiotics – To prevent secondary bacterial infections of skin lesions and lymph nodes, antibiotics may be prescribed by a vet.
- IV fluids – Dehydrated cattle can be given intravenous fluid therapy.
- Wound care – Necrotic skin nodules should be kept clean to enable healing. Antiseptic ointments can be applied.
- Nutritious diet – High protein diet aids in speedy recovery by boosting immunity.
- Isolation – Infected cattle should be isolated from the herd to contain viral spread.
In most cases, cattle recover from LSD within 1-2 months. But morbidity due to weight loss, infertility, reduction in milk yield can be substantial.
Prevention of Lumpi Skin Disease
Preventing the introduction and spread of LSDV is key to controlling this infectious cattle disease:
- Quarantine – Isolate and monitor newly purchased or imported cattle for 28 days before mixing with the herd.
- Vector control – Use insect repellents, nets, fans; avoid stagnant water to reduce vector insects.
- Disinfection – Clean and disinfect farm premises, equipment with 1% Sodium hypochlorite or citric acid.
- Safe disposal – Proper disposal of carcasses, manure, bedding by deep burial or incineration.
- Restricted entry – Allow only essential personnel on farm. Provide foot dips and protective clothing.
- Vaccination – Immunize cattle using sheeppox or goatpox vaccines during outbreaks. Requires regular boosters.
- Movement control – Avoid introducing new cattle or taking animals to shows/markets during outbreak.
Following biosecurity and hygiene protocols is key to preventing spread of LSD virus on farms and animal holdings.
LSD Vaccination in Cattle
There are no vaccines specifically designed against lumpi skin disease virus. However, sheeppox and goatpox vaccines can be used in cattle for immunization against LSD:
- Live-attenuated and inactivated sheeppox vaccines elicit protective immune response and prevent clinical disease in cattle caused by LSDV.
- Sheeppox vaccines like Romanian Fanar vaccine and Yugoslavian RM-65 sheeppox vaccine are commonly used.
- Vaccination provides immunity for 3-5 years. Annual vaccination is recommended in endemic areas.
- Vaccination during outbreaks combined with quarantine, disinfection, vector control is the most effective control strategy.
- Adverse reactions are rare but edema and nodules at injection site can sometimes occur after vaccination.
- Pregnant cows should not be vaccinated to avoid abortion risk.
Along with vaccination, preventing insect bites for 1 month post-immunization is also necessary as vectors can transmit infection from field virus.
Zoonotic Potential of LSDV
Lumpi skin disease virus is not known to transmit from cattle to humans. There is no evidence of LSDV having zoonotic potential.
Human infections with Capripoxviruses have not been reported to date. LSDV is strictly cattle-specific and adapted to bovine hosts.
However, theoretically cross-species transmission cannot be ruled out. People working with infected cattle can use personal protective equipment to avoid exposure.
Pasteurization of milk from infected/vaccinated cattle destroys any virus if present. So consumption of boiled milk is considered safe for humans.
Conclusion
Lumpy skin disease is a highly contagious viral infection of cattle and buffaloes characterized by skin nodules and fever. Spread by insect vectors and contact, it causes significant economic losses in livestock. Strict biosecurity, vector control and sheeppox vaccination are key strategies for effective LSD management. Although zoonotic risk appears low, further studies are needed considering the expanding global range of LSDV. Implementing surveillance, containment and control guidelines is crucial for preventing LSD epidemics.
