Systematic Veterinary Virology

TRANSMISSION

• Pseudorabies spreads mainly by direct contact between swine. Nasal discharges and saliva from infected pigs contain the virus and the virus enters susceptible pigs though ingestion or inhalation. Contaminated drinking water, bedding, and other objects such as clothing and instruments also act as a source of infection.
• Recovered pigs may remain carriers of the virus and later can infect susceptible pigs or cattle with which they come into contact. The disease has also been introduced to swine farms by introduction of carrier swine. Dogs and cats also become infected through contact with infected pigs. Dogs, cats, and wild animals are potential spreaders of the disease within an endemic area.
• Other uncommon methods of spread include via semen, vaginal secretions, colostrums, contaminated veterinary equipment e.g. needles and syringes and transplacental infection. Dogs can get the infection if fed with meat from infected pigs. In the same ways pigs also can infection, if the feed contains infected meat.
• Wind-borne spread from farm to farm can occur under favourable conditions (Upto 2 Km). Rats and wild pigs act as a reservoir for the virus. Movement of live pigs is considered the most likely method of introducing the disease in a new area.