The 25-year-old Kampot province woman who died of avian influenza in Vietnam last month may have gotten the virus in a rare instance of human-to-human transmission, according to the spokeswoman from the World Health Organization in Cambodia.
An epidemiological field investigation into Tit Sakhan’s Jan 30 death revealed that she had limited exposure to chickens and may have contracted the virus from her brother, who died days earlier, spokeswoman Maria Cheng said.
“From the investigation it does look like she had minimum exposure to the handling of chickens,” she said. “It does open the door to the possibility that she contracted the virus from her brother.”
Tit Chaing, 14, died on Jan 24 from bird flu-like respiratory failure, but no tests were conducted to determine if he had the virus.
“The brother was very involved in the slaughter and care of chickens,” Cheng said, adding that Tit Sakhan “was very involved in the preparation of his body for burial.”
Since Tit Chaing was never tested, authorities will not be able to prove that this was an instance of human-to-human contact, the WHO spokeswoman said.
The possibility, however, would not necessarily mean that the virus has mutated into a new, more transmissible form, she said. “There have been suspect cases of human-to-human transmission in Vietnam and Thailand and tests have shown that the virus did not change in those instances,” she said.
Following Tit Sakhan’s death, 16 people from her native Koh Chamkar village, including her relatives, initially tested negative for the virus. But, Cheng said, further tests are needed.
“The concern is that the testing was done too quickly…. Antibodies can take 14 days to develop, so further tests are needed,” she said.
Unlike other diseases, however, bird flu cases involving human-to-human contact do not usually spread the disease to a “third generation” of people, Cheng said.
“With some diseases, when you see one case, you assume 20 more are infected. That is not the case with H5,” she said. “It is certainly possible that only one person was infected because the spread of the disease is quite difficult and most likely requires close contact.”
Sorn San, director of the Animal Health and Production Investigation Center, said that tests on chickens from Kandal province’s Takmau district performed Monday were negative for bird flu.
Those tests were conducted after two chickens were found to have bird flu in Takmau district’s Prek Russei commune on Friday.
“We have no further outbreaks at this time,” Sorn San said.
He also said that there has been no conclusion as to whether the virus entered Cambodia through wild birds or poultry from neighboring countries.