Porcine Circovirus Associated Disease (PCVAD)
Porcine Circovirus infection is almost ubiquitous. PCV is a small, resistant, circular, single-stranded DNA virus which can grow in a wide range of porcine cell lines. The virus multiplies in cells of the porcine intestine, respiratory tract, macrophages (white blood cells which kill bacteria), and T and B lymphoctes (which control immunity).
PCV type 1 (PCV1) is non-pathogenic, but PCV2a and, more recently, PCV2b infections cause or contribute to several conditions, most importantly PMWS, PDNS and reproductive conditions such as mummified pigs and abortions. In some cases, the virus has been accompanied by other viruses such as porcine parvovirus.
Infection is generally oronasal, transplacental or venereal, and disease is produced when infection of the cells of the lymphoid system allows high levels of virus to accumulate in the blood. In foetuses, this can result in foetal death, mummification and abortion, in weaned pigs it can cause PMWS, the commonest form of disease, resulting in wasting and mortality once maternal antibody levels have declined, and in older pigs with high viral loads and low antibody levels, in PDNS.
Porcine circovirus disease (PCVD) is the term for a viral disease of pigs that has emerged as a major problem in the United States.
Porcine circovirus type 1 (PCV1) was first identified in 1974 and was recognized as a non-disease-causing agent that frequently occurred in laboratory tissue cultures. In 1991, swine veterinarians in western Canada began reporting cases of nursery pigs falling ill with clinical signs that included a progressive loss of body condition, visibly enlarged lymph nodes, difficulty breathing, and less commonly diarrhea, pale skin, and jaundice.
The name “postweaning multisystemic wasting syndrome” (PMWS) was applied to the disease. In 1997, a new circovirus (PCV2) was isolated from these outbreaks. Since that time, researchers have been able to successfully reproduce the disease by inoculating pigs with PCV2 in the laboratory.
PMWS has now been reported from most pig-producing countries of the world. Additional PCV2-associated diseases have also been described including reproductive failure, respiratory disease in finishing pigs, and an unusual skin and kidney disease referred to as porcine dermatitis and nephropathy syndrome (PDNS).
This prolific virus impairs the immune system and leaves pigs susceptible to other swine diseases and pigs affected may experience increased mortality, poor growth and weight loss, progressing to the level of severe thinning, weakness, and a considerable longer time to market.
Signs & Symptoms
The signs and symptoms of Porcine Circovirus (PCVD) are:
- Diarrhea
- Difficulty Breathing
- Enlarged Lymph Nodes
- Stomach Ulcers
- Jaundice
- Skin Rashes
- Possible Sudden Death
How PCVD is Transmitted
Exposing pigs to other pigs or boots, clothing, or equipment that have been around other pigs greatly increases the risk for disease transmission.
Visible bodily secretions (blood, urine, feces, or mucus) from infected pigs is another major transmission factor.
Preventing PCVD
The following vaccines are very effective at preventing Porcine circovirus disease. Vaccination programs need to be modified to each swine operation and should be developed in consultation with your veterinarian..
Porcine Circovirus Disease (PCVD)
Compiled & Shared by- Team, LITD (Livestock Institute of Training & Development)
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