Effects of swine flu in pigs studied

BANGKOK, May 11 (UPI) -- Thai scientists who studied the pathology of H1N1 swine flu in piglets said the animals displayed flu-like symptoms within 1-4 days after infection.

The researchers, led by Roongroje Thanawongnuwech of Chulalongkorn University in Bangkok, found all the 22-day-old infected animals were shedding virus two days after infection. The pigs were infected with both the H1N1 strain of swine flu and the less dangerous H3N2 subtype.

"The results demonstrated that both swine flu subtypes were able to induce flu-like symptoms and lung lesions in weanling pigs," said Thanawongnuwech. "However the severity of the disease with regard to both gross and microscopic lung lesions was greater in the H1N1-infected pigs."

All infected pigs developed respiratory symptoms such as nasal discharge, coughing, sneezing and conjunctivitis. Upon pathological examination, lung lesions large enough to be seen by the naked eye were observed, he said.

"These lesions were characterized by dark plum-colored, consolidated areas on lung lobes and were most severe two days after infection, especially in the H1N1-infected pigs, where approximately a third of the lung was covered." He said. "The course of infection was limited to less than a week and none of the animals died."

The study is detailed in the Virology Journal.