February 19, 2008

US researchers discover mutated strains of swine disease

US researchers have discovered that porcine circovirus (PCV) are mutating through combination with other pathogens, which could pose serious threats to global pig populations.

PCV2 can cause abortions, pneumonia, systemic infection, and lesions in lymph tissues, kidney, liver and lungs. In addition to these, the new mutation causes swelling of the spleen and fluid in body cavity, lungs, abdomen and intestines.

Researchers found that recent mutations of PCV, which make the disease more difficult to control and treat, can cause widespread disease. Other pathogens can combine with the virus to increase fatality rate, but veterinarians and producers do not have any resources to handle these potential threats.

To determine how mutated forms of PCV cause deadly illness, scientists have studied pigs that are exposed to a virus combination.

Roman Pogranichniy, a Purdue School of Veterinary Medicine virologist, said they think bovine viral diarrhoea virus-like pathogen and other swine virus combine with PCV to attack the animals' system and become more virulent.

Scientists are now studying virus-caused lesions and blood of PCV2-infected pigs to understand its method of transmission and how it progressed to become more deadly.

According to Pogranichniy, the amount of PCV2 virus found in the animals had a direct relationship to how sick the pigs became.

PCV has spread all over the world in the past decade, but mortality rate is usually low. However, farms with mutated and combined strains of PCV are observed to have a mortality rate increase from 35 percent to 50 percent.

According to Pogranichniy, further probing is required into cases of the latest PCV mutation that are characterised by lesions produced in the blood vessels.