Dec 27, 2007 (CIDRAP News) – The World Health Organization (WHO) today announced its first confirmation of a human case of H5N1 avian influenza in Pakistan, in a young man who was part of a family cluster of suspected cases and died of the disease.

The man was one of several brothers who fell ill after caring for another brother—a veterinarian who had become ill after helping to cull chickens in the Peshawar area. The WHO´s announcement today thus signals not only Pakistan´s first confirmed human case, but also a rare instance of apparent human-to-human transmission. The WHO said the virus did not spread beyond the family.

The WHO posted a brief statement today saying the agency´s H5 reference laboratory in Cairo and its Collaborating Center for Reference and Research on Influenza in London identified the H5N1 virus in samples from one member of the family group of patients. The agency said additional analysis, including gene sequencing, is under way.

Citing information from Pakistan´s health ministry, John Rainford, a WHO spokesman in Geneva, identified the man as a 25-year-old from the Peshawar area who became ill on Nov 21, was hospitalized Nov 23, and died Nov 28.

"He is the third of four brothers who developed proven or suspected pneumonia with illness onset dates between 29 October and 21 November," Rainford told CIDRAP News. "The brothers provided care for one another and had close personal contact in both the home and hospital."

According to previous reports, the family group was among eight people in Pakistan´s North-West Frontier province, near the Afghan border, who were previously diagnosed with avian flu on the basis of preliminary tests in Pakistan. The eight included four brothers and a cousin from the same family, plus three other people. Another brother also had a flu-like illness but died without being tested.

The other patients who tested positive have been described as a man and his niece who were involved in poultry culling, plus a male farm worker.

The WHO said previously that limited person-to-person transmission might have occurred among close contacts in the Pakistan situation. Today the agency stated, "The preliminary risk assessment found no evidence of sustained or community human-to-human transmission.

"All identified close contacts including the other members of the affected family and involved health care workers remain asymptomatic and have been removed from close medical observation," the WHO added.

Rainford today suggested the possibility that none of the other apparent cases in Pakistan will be confirmed by the WHO. "We´ve got a host of technical issues," he said. "There are practicalities of samples breaking down over time in the transportation."

However, a lack of further confirmations would not change the assumption that person-to-person transmission probably occurred among close contacts, he added. "The clinical evidence is that they did match the case definition of H5N1, so the risk assessment is unchanged."

Rainford said the problems with sample quality could also affect the effort to further characterize the virus through genetic sequencing.

Meanwhile, he said another suspected H5N1 case has been found in the same region of Pakistan as the recent cluster but with no known connection to it. The suspected case is in an 8-year-old who had contact with sick poultry before falling ill, he reported.

"The new case is in the same region, but there´s no epidemiologic link to the other cases," Rainford said, adding that he didn´t know the specific location.

The WHO´s case confirmation came on the same day as the assassination of Pakistan´s former prime minister, Benazir Bhutto, which sparked unrest in the country. Rainford said he couldn´t speculate about how the assassination and related events might affect Pakistan´s response to the H5N1 threat.

"There might be implications for investigations or movement of samples, but I really couldn´t say at this point," he said. He said a special WHO team that helped investigate the human cases in Pakistan returned to Geneva "sometime ago."

Today´s WHO announcement makes Pakistan the 14th country with confirmed human H5N1 cases. The WHO´s global case count has reached 343 cases with 212 deaths.

Meanwhile, Egypt´s health ministry reported two more human H5N1 cases in the country today, a day after the WHO confirmed Egypt´s 39th case, according to a Reuters report. Amr Kandeel, head of communicable disease control, said the patients were from Damietta and Menoufia and were both hospitalized, the story said.

The state news agency, MENA, identified the Menoufia patient as 22-year-old Nora Aboul Abbas Mohamed but gave no details on the other patient, Reuters reported.

The WHO has not yet recognized the two cases, which would bring Egypt´s total to 41, with 16 deaths.