Vesicular stomatitis
Aetiology Epidemiology Diagnosis Prevention and Control References
AETIOLOGY
Classification of the causative agent
Virus family Rhabdoviridae, genus Vesiculovirus
Major serotypes: New Jersey, IndianaResistance to physical and chemical action
Temperature: Inactivated by 58°C for 30 min
pH: Stable between pH 4.0 and 10.0
Chemicals: Ether and other organic solvents sensitive
Disinfectants: Destroyed by formalin (1%)
Survival: Survives for long periods at low temperatures EPIDEMIOLOGY
- Morbidity rate variable, up to 90% in a herd
- Low mortality rate
Hosts
- Human (minor zoonosis)
- Domestic hosts: equidae, bovidae, suidae
- Wild hosts: white-tailed deer and numerous species of small mammals in the tropics
Transmission
- Contamination by transcutaneous or transmucosal route
- Arthropod transmission (Phlebotomus, Aedes, etc.)
Seasonal variations: VS is more frequent in the rainy season in tropical areas, although in some countries is also registered during the dry season. Generally disappears at the first frosts in temperate zones
Sources of virus
- Saliva, exudate or epithelium of open vesicles
- Vectors
- Soil and plants (suspected)
Occurrence
The disease is limited to the Americas. (It was described in horses in France in 1915 and 1917, and in South Africa in 1886 and 1887.)
For detailed information on occurrence, see recent issues of World Animal Health, the OIE Bulletin and Weekly and Monthly Epidemiological Report PANAFTOSA/PAHO/WHODIAGNOSIS
Incubation period is up to 21 days
Clinical diagnosis
The symptomatology is similar to that of foot and mouth disease (FMD), with which it can easily be confused (but horses are resistant to FMD and susceptible to VS)
- Excessive salivation
- Blanched raised or broken vesicles of various sizes in the mouth:
- Horses: upper surface of the tongue, surface of the lips and around nostrils, corners of the mouth and the gums
- Cattle: tongue, lips, gums, hard palate, and sometimes muzzle and around the nostrils
- Pigs: snout
- Lesions involving feet of horses and cattle are not exceptional
- Teat lesions occur in dairy herds
- Foot lesions and lameness are frequent in pigs
- Recovery in around 2 weeks
- Complication: loss of production and mastitis in dairy herds due to secondary infections, lameness in horses
Lesions
Limited to the epithelial tissues of the mouth, teats and feet
Differential diagnosis
Clinically indistinguishable:
- Foot and mouth disease
- Swine vesicular disease
- Vesicular exanthema of swine
Other differential diagnosis:
- Infectious bovine rhinotracheitis
- Bovine viral diarrhoea
- Bluetongue
Laboratory diagnosis
Procedures
Identification of the agent
- Virus isolation: inoculation into embryonated chicken eggs; mice; tissue culture systems (chick fibroblasts, pig kidney, BHK-21, Vero); footpad of guinea pigs; horses and cattle; snout of pigs
- Viral antigen detection by complement fixation test, ELISA or neutralisation tests in tissue culture, embryonated chicken eggs, or suckling mice
Serological tests
- Virus neutralisation
- ELISA
- Complement fixation
(prescribed tests in the Manual) Samples
Identification of the agent
- Epithelial tissue covering the vesicles placed in buffered glycerol or frozen
- Vesicular fluid aseptically collected and frozen
Serological tests
- Paired acute and convalescent serum samples
NB!! Serum antibodies reach high levels but reinfection may occur. As for FMD special precautions are required when sending perishable suspect VS material within and between countries. See Manual, Chapter 1.4. PREVENTION AND CONTROL
No specific treatment. Antibiotics may avoid secondary infection of abraded tissues
Sanitary prophylaxis
Animal movement should be restricted and a laboratory diagnosis must be performed rapidly. Trucks and fomites should be disinfectedMedical prophylaxis
Inactivated and attenuated virus vaccines have been experimentally tested, but are not yet available commercially
NB!! Differentiation from FMD is very important REFERENCES AND OTHER INFORMATION
- Reference experts and laboratories
- Classified as an OIE List A disease (A020)
- Chapter 2.1.2. in the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals.
- Terrestrial Animal Health Code
- Numerous other references - see the Index
- World Animal Health .
- Current Animal Health Status (Disease Information)
---------------------------------------------
Contact : scientific.dept@oie.int