Vesicular stomatitis is an infectious viral disease of bovines characterized by the development of vesicular lesions on the mouth, muzzle, lips, gums, feet, and sometimes in the udder of lactating cows. The disease primarily occurs in horses but a significant cause of economic loss in dairy farms in south Asian countries. The disease has clinically resembled FMD in cattle. The morbidity rate varies from 6 to 11%, with an average farm incidence of 2 to 3%. The virus affects many domestic animals like cattle, horses, swine, sheep, and goats. In cattle and swine, the disease is very close to Foot and Mouth Diseases (FMD).
Vesicular stomatitis (VS) is a zoonotic disease and may cause influenza-like diseases in human beings, mainly in arm workers and veterinarians who directly contact the disease. The disease also has some other public health significance. The diseased animal and wildlife reservoir hosts serve as the source of infection. The saliva of infected animals and vesicular fluids is highly infective. In dairy cattle, lateral transmission occurs by direct or indirect contagion through ingestion of contaminated food or water from common feeding and watering troughs.
Important Information on Vesicular Stomatitis
The VS causes blisters in the mouth, muzzle, lips, gums, palate, tongue, udders, teats, sheath, and coronets. The blisters rupture and shed necrotic tissues. The ruptured blisters are so painful that the animal is unable to eat or drink. As a result, the milk production in dairy cattle decreased dramatically. Most of the animals recovered automatically without treatment. However, in severe cases, the animals may die due to secondary bacterial infection and other complications.
What is the Cause of Vesicular Stomatitis?
The Vesiculo virus causes the disease under the family Rhabdoviridae. The virus has two distinct antigens, like the New Jersey type and the Indiana type in the United States of America. The Vesiculo virus is a bullet-shaped single-strand negative-sense RNA virus. The virus has five genes like N (Nucleocapsid protein), P (phosphoprotein), G (glycoprotein), M (Matrix protein), and L (Large protein). The New Jersey and Indiana types are identified in recent outbreaks in America.
Transmission and Epidemiology of VS Virus
Local injuries in oral, pedal, or teat through coarse roughage or herd pellets facilitate the entry of the virus. Transmission of the disease may occur by grazing on contaminated pasture. Transmission over long distances occurs by insect vectors like sandflies, black horses, and mosquitoes.
The water serves as a significant source of contamination of the VSV. The virus is mainly transmitted by direct contact with the affected animals. VS is endemic in Western, Central America, and Mexico but very few natural occurrences outside the Western Hemisphere. The clinical resembles the disease from 10-12%, but the seroprevalence may reach up to 100% in the affected herd.
Pathogenesis of VS in Cattle
Many domestic and wild animals have serological prevalence, but clinical diseases occur in some species. The pathogenesis of the virus are:
- After entry of the virus, there is a primary viremia followed by its localization in the mucous membrane of the mouth and skin around the mouth and coronets.
- In 30% of cases, typical cysts develop as a result of focal replication and intercellular edema.
- The vesicles rupture and local necrosis occurs, which is very painful and irritating to animals.
What are the Symptoms of Vesicular Stomatitis?
The incubation period of VSV varies from 2-8 days, and initially, there is an onset of mild fever. However, when there are clinical signs, it appears the animal is not febrile.
- There is the sudden onset of mild fever in infected cattle.
- Blisters appear on the dorsum of the tongue, dental pad, lips, and buccal mucosa.
- The blisters rupture soon and caused drolling of salivation.
- The affected cattle are unable to eat and drink.
- During an outbreak, buccal cavity examination reveals erosive, necrotic lesions on the tongue and cheeks in many affected animals.
- A marked decrease in milk yield with lesions on the teat and udder is observed in milking animals.
- Mastitis is the expected sequel of vesicular stomatitis.
- Laminitis and coronets are a consequence of VS.
Pathological Lesions of VS in Cattle
- The lesions are vesicular and necrotic changes located in oral mucosa, feet, teat, and udders like the FMD and Vesicular Exanthema in cattle.
- Ulcers may develop after the rupture of the cysts in the mouth and upper digestive tract.
- Necrotic lesions in the sensitive lamina and coronary bands of the horses.
Diagnosis of Vesicular Stomatitis
The diagnostic method of VS in the field and laboratory are as follows:
- The disease can be diagnosed based on the history of exposure and clinical signs.
- The confirmatory diagnosis can be made by virus isolation.
- The complement fixation test is used to differentiate the two strains of the virus.
- Serological tests like Fluorescent Antibody, resin agglutination inhibition, virus neutralization, and ELISA are also used for its confirmation.
- PCR is the most effective and definitive method of diagnosis.
Differential Diagnosis of Vesicular Stomatitis in Cattle
The disease should be differentiated mainly from the following diseases:
- Foot and Mouth Disease (FMD): which is more severe with high morbidity and mortality. FMD is not occurring in horses.
- Vesicular Exanthema, which is mainly seen in pigs.
- Bovine Malignant Catarrh, where vesicles are not formed.
- Swine vesicular disease.
- Blue Tongue.
- Infectious Bovine Rhinotracheitis.
- The Bovine papillomavirus causes bovine Papular stomatitis.
How Do You Treat Vesicular Stomatitis in Cattle?
The treatment of viral disease is not readily available, and there is very little specific treatment. The management protocol of the disease are as follows:
- The disease is self-limiting and recovered within 10-12 days without treatment.
- Application of mild antiseptic mouthwash and footbath may help in the rapid recovery of ailing animals with the restoration of appetite.
- An antibiotic like Ampicillin or Penicillin, or Sulfa drugs can be given to prevent secondary bacterial infection.
- The affected animals should be provided with a soft, palatable bland diet with clean drinking water, and coarse food like straw or hay should be avoided.
Prevention and Control of VS in Cattle
The preventive methods of the disease are as follows:
- The disease can be controlled by adopting standard hygienic procedures and quarantine precautions on farms.
- Recovered animals are immune to infection for about six months.
- Affected animals should be isolated and keep separate from the healthy animals at least for 14 days after recovery.
- Vaccines of VSV are available in some Latin American countries.
Zoonotic Importance of Vesicular Stomatitis
The disease has zoonotic importance and may affect human beings. The farmworkers, veterinarians, caregivers, and farm laborers mainly affected by VSV. The virus causes flu-like symptoms, headache, itching, and sneezing. The disease also recovers without treatment. You must be cautious and wear protective clothing while handling sick animals.
Final Advice on Vesicular Stomatitis in Cattle
VS is a common virus disease in American and some other parts of the world. The disease resembles the FMD and some other viral disease and must be differentiated. The disease is self-limiting and mainly recovered without treatment. However, as a farm owner, you must take necessary preventive measures on your farm.