Observations on the epidemiology of porcine parvovirus.
Evidence presented suggests that porcine parvovirus is highly stable and infective. Introduction of virus to susceptible herds results in 100% infection rate within the following 3 months. Active immunity is associated with high persistent levels of haemagglutination-inhibitating (HI) antibody (greater than 256), piglets suckling immune sows acquiring HI titres between 10,000 and 40,000. Loss of passive immunity, measured by HI, occurs in a majority of pigs between 14 and 26 weeks of age (mean 21 weeks), whilst an average of 25% (2-47%) of pigs lose HI titres between 26 and 36 weeks of age. Susceptibility to challenge with virus does not occur until 3-5 weeks following loss of HI titres. In endemically infected herds 98-100% of adult pigs show serological evidence of active immunity. A significant proportion of gilts may not be actively immune to porcine parvovirus at the time of first service, and subsequent infection may occur while these gilts are pregnant.
D000367:Age Factors; D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D001315:Australia; D005260:Female; D007110:Immunity, Active; D007112:Immunity, Maternally-Acquired; D008297:Male; D010321:Parvoviridae / Q000276:immunology; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology* / Q000276:immunology; D006113:United Kingdom; D014777:Virus Diseases / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary*
D000914:Antibodies, Viral