Other name: pseudorabies
Contagious disease caused by a herpesvirus mainly affecting pigs, but also carnivores, ruminants and horses.
Worldwide geographical distribution, especially in those countries where pig farming is significant. Declaration to the OIE by the following countries (in 2004): Brazil, Columbia, Costa Rica, Cuba, Mexico, Panama, USA. Few outbreaks and low level of infection, difficult to calculate.
Pigs, wild boars, dogs, cats, bovines, ovines, horses.
Humans are not susceptible to the disease.
A DNA enveloped virus from the Herpesviridae family, a sub-family of Alpha-herpesviridae: type 1 porcine Herpes virus.
A neurotropic virus that also causes respiratory and genital tropism in pigs. Lytic infection cycle < 24h. Ability to establish latent infection in the nervous system.
Stable between 4 and 25°C and at a pH of 6-8. Sensitive to classical disinfectants. May remain virulent in the outside environment for several weeks.
Short incubation period: 2-5 days.
Pig:
In its clinical form, the disease progresses differently according to age and sex. In young pigs under 3 months old, the nervous system is affected. Animals for fattening suffer from the respiratory form and reproductive disorders occur in sows.
Piglets less than 2 weeks old: fever (>41°C), meningoencephalitis (trembling, convulsions, paddling) death occurs in only a few hours.
Piglets from 2 weeks to 3 months old: fever, inappetence, meningoencephalitis (hyperesthesia, convulsions, pharyngeal paralysis). Convalescence with retarded growth or death.
Fattening pigs: flu-like respiratory symptoms (cough, dyspnea, sneezing), general state of health affected (exhaustion, inappetence, fever). Significant retarded growth, rarely death.
Sows: inappetence, casting, stillbirth in the whole or part of the litter.
Wild boars: asymptomatic form the most often.
Other species:
Clinical presentation of encephalomyelitis (pseudorabies) with pharyngeal paralysis.
In carnivores and ruminants: intense pruritis, at the virus inoculation point. Rapidly evolves towards death (48h).
Cats: frequently infected. Inconstant pruritis, encephalomyelitis, lethargy, non-aggressive anxiety, paralysis of the pharynx, ptyalism, anisoscoria, rapid death (6-48h).
Dogs: ditto + self-mutilation of the mouth.
Ruminants: ditto + mastication.
Horses: absence of pruritis, as in pigs.
Absence of any specific treatment.
Sanitary prophylaxis
In a disease-free or low-contaminated zone: basic hygiene + introduction of serologically controlled animals from disease-free farms. Vaccination proscribed.
Medical-sanitary prophylaxis
In contaminated zones, combination of vaccination + sanitary precautions
Pure-bred pigs:
- If the level of infection is low (<20%): regular serological detection and rapid slaughter of positive cases. Interruption as soon as 2 negative tests at 2-3 months interval are obtained for all pure-breds
- If the level of infection is high (>20%): total slaughter or medical-sanitary prophylaxis (vaccination).
Fattening pigs: Cleaning/disinfection after fattening.
Other species: avoid all contact with pigs, do not feed domestic animals raw pork meat or offal.
Vaccination does not stop any latent or asymptomatic infection occurring. It offers clinical protection and significantly reduces virus excretion in case of infection.
Two types of vaccine are available: Inactive or attenuated live virus vaccines. Both can be produced from deleterious viruses. They enable vaccinated animals to be distinguished from infected animals.
In sows, the vaccination aims to protect piglets via the colostrums. Only use inactive vaccines.
For fattening pigs, both types of vaccine can be used.
In general, only pigs are vaccinated, but only under certain circumstances. Ruminants and carnivores can be vaccinated with inactive vaccines (use outside MAA).