Possible H5N1 family cluster probed in Pakistan

Dec 17, 2007 (CIDRAP News) – The World Health Organization (WHO) has sent a team to Pakistan to investigate at least eight suspected human cases of H5N1 avian influenza in the same general area, including cases in four brothers and two of their cousins, according to news services.

WHO spokesman Gregory Hartl said limited human-to-human transmission in the cases is possible, according to an Associated Press (AP) report published yesterday. However, he told Nature that 40 contacts of the suspected case-patients have tested negative.

If confirmed, the cases will mark the first human H5N1 infections in Pakistan. They also appear to constitute the largest cluster of related infections since eight cases (seven confirmed, one probable) occurred among relatives in North Sumatra in May 2006. Transmission of the disease from a 10-year-old boy to his father was confirmed by laboratory testing in that episode.

In a Dec 15 statement, the WHO said Pakistan's ministry of health had reported eight suspected cases in the Peshawar area, in the wake of culling operations to control poultry outbreaks there. Peshawar is in the country's North-West Frontier province, near the Afghan border, where most of the country's poultry outbreaks have occurred.

Samples from the patients tested positive in Pakistan's national laboratory and were being sent to a WHO reference lab for confirmation and further analysis, the WHO said.

Doctors from the WHO in Geneva and Cairo and others from US Navy Medical Research Unit 3 in Cairo were on their way to Pakistan yesterday to help investigate the cases and combat the disease, according to a Dec 16 Bloomberg news report. The team planned to track down, treat, and test contacts of the suspected case-patients, according to the Nature report.

Details of the suspected cases remained somewhat hazy today, as news reports varied in some respects.

According to the AP, Hartl said the illnesses involved four brothers, two of whom died, and two cousins, all from Abbotabad, a city about 30 miles north of Islamabad. Specimens were never collected from one of the deceased brothers. The two men who died had been students at an agricultural college in Peshawar; they were not involved in culling poultry, but they visited another brother when he was hospitalized, the story said.

Also among the suspected cases were a man and his niece from the Abbotabad area and a person who slaughtered poultry in Mansehra, 15 miles away, Hartl told the AP. He said some of the patients had had only mild symptoms and were never hospitalized.

The Bloomberg News report, also based on information from Hartl, concurred that the suspected case-patients included four brothers. The first case was in an agriculture official who fell ill after culling poultry in the Abbotabad area in late October. He was cared for by two of his brothers, both of whom subsequently died, one about a month ago and the other on Nov 29. A third brother of the first man also got sick, was hospitalized, and recovered, the story said.

The suspected cases also included two of the four brothers' cousins, who had only mild symptoms, plus a man and his niece who were involved in culling poultry in the area, Bloomberg reported. (It was not clear if the cousins were involved in culling.) Another case was in a male farm worker from Mansehra.

Still another brother of the first man to fall ill lives in New York state but flew to Pakistan to attend the funeral of one of his deceased brothers, according to Bloomberg. On his return, he told his physician that he might have been exposed to avian flu and quarantined himself at home, after which his son experienced flu-like symptoms. Samples from both father and son tested negative in state and federal laboratories last week, the story said.

Hartl told Bloomberg it was too early to tell whether the cases all spread from birds or involved limited person-to-person spread. He said some of the patients kept chickens and quail, and it was unclear what kind of protective equipment they used during culling.

The Nature report said Pakistan was slow to inform the WHO of the possible cases, boding ill for the agency's hope of detecting any person-to-person transmission early and quickly providing antiviral treatment to stop a potential pandemic. The story said the first cases occurred in mid-November at the latest, but Pakistan didn't officially inform the WHO until Dec 12.

See also:

Dec 15 WHO statement
http://www.who.int/csr/don/2007_12_15/en/index.html

Jun 23, 2006, CIDRAP News story on human-to-human transmission in North Sumatra cases
http://www.cidrap.umn.edu/cidrap/content/influenza/panflu/news/jun2306cluster.html

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