Pig vesicular disease
The swine vesicular disease (Syn. Porcine vesicular disease , Crohn's vesicular suum ) is a viral disease of swine . In addition to pigs, humans are also susceptible, so that the disease can be classified as a zoonosis . In pigs it manifests itself as vesicles on the head and claws , in humans it can cause aseptic meningitis .
Swine vesicular disease is a notifiable animal disease . The disease was first observed in Italy in 1966 and has since occurred in several countries in Europe and Asia . The last outbreaks in Europe were in 1998 and Italy in 2000. The disease last occurred in Germany in 1985.
Pathogen and Pathogenesis
The causative agent is the Swine Vesicular Disease Virus (SVDV) ( genus Enterovirus , family Picornaviridae ), which is divided into different strains based on differences in the antigens. The SVDV is closely related to the human Coxsackie B-5 virus . It probably emerged from it by point mutation. The virus is 30 to 32 nm in size and its genome consists of a single-stranded RNA .
The virus is extremely stable, it tolerates a pH range from 2 to 12.5. The virus can remain infectious in excrement for 140 days. Salting, smoking , deep-freezing and curing do not inactivate the virus. However, at a temperature above 60 degrees Celsius it is quickly inactivated.
It is transmitted through direct contact with the virus. Various outbreaks have occurred due to inadequately heated kitchen waste being fed pork.
After infection , the virus multiplies locally at the entry point and the regional lymph nodes . The subsequent first viraemia is clinically inconspicuous and leads to further colonization of internal organs. This is followed by a second viremic phase, after which viruses can be detected in all organs. With the formation of neutralizing antibodies , the number of viruses decreases again from the 5th day after infection and the disease usually heals in three weeks.
Clinical picture
The incubation period is 2 to 7 days. The first clinical signs are unwillingness to eat , lameness and fever. Blisters ( aphthae ) then form on the claws, proboscis , tongue and teats . Occasionally, especially in experimentally infected animals, symptoms of the central nervous system (rowing and compulsive movements, sensitivity disorders) appear.
In suckling piglets, high losses occur as a result of the sharp decrease in milk yield in sick sows.
diagnosis
In pigs, the disease cannot be clinically distinguished from foot-and-mouth disease , vesicular stomatitis and vesicular rash .
The virus can be isolated from vesicular fluid, skin and mucous membrane , blood and serum and grown in pig kidney cell cultures which show cytopathic changes. Using ELISA , viral antigen can be detected in the material of the vesicles.
Combat
The animal disease is notifiable. The fight against vesicular pig disease is based on animal health regulations and is initiated by the veterinary authorities. In most European countries, outbreaks of disease are quarantined and the affected herds are killed. A vaccine is not available.
