Bird flu: Victims sick in three days

People infected with Asia’s bird flu get sick about three days after exposure to the virus, suffering fevers and coughing, the World Health Organisation has found, in the first clinical data of patients with the current strain.

The data was collected by Vietnamese doctors on 10 of their country’s patients infected with the H5N1 strain of bird flu that has affected poultry across much of the Asian continent and jumped to humans in Thailand and Vietnam.

The overall human death toll stood at 19 today.

The 10 cases studied were farmers and children, with most believed to have had contact with sick chicken and ducks at their farms. In one case, a sick boy had frequently held roosters at cock fights, and typically walked through a poultry market on his way to school.

WHO noted on its website that the mortality rate was very high – eight of the 10 patients died – but cautions that the cases are too few “to be representative of the full range of the illness that H5N1 may cause.”

Doctors may not be identifying milder infections of bird flu, and cases in which the patient doesn’t seek treatment and recovers may be going unnoticed.

Ten governments in the region have dealt with strains of bird flu since South Korean officials reported an outbreak there in early December. Some of the affected Asian countries, as well as the United States, are being hit with milder bird flu strains not thought to pose as much danger to people.

At least 50 million chickens have been slaughtered across Asia in government-ordered culls to contain the outbreak here, and major poultry importers have banned exports of remaining poultry from many bird flu-affected countries, devastating the industry.

The disease so far has jumped to people only in Vietnam and Thailand, in cases mostly traced to direct contact with sick birds. Health officials believe the virus is passed through birds’ faeces.

WHO officials have expressed concern that China may also be suffering from human cases given the broad range of poultry infections in that sprawling country, which has confirmed avian flu in 14 of its 31 regions.

In the Vietnamese study summarised by WHO, seven of the patients were described as students – or schoolchildren – and three of them as farmers.

The median time for the disease’s onset after suspected exposure was three days, with top body temperatures during the first day of illness ranging from 38.3 C (100.9 F) to 39 C (102.2 F). The flu-like illnesses, with coughing and often with diarrhoea, typically lasted about a week, with top fevers ranging from 38.5 C (101.30 F) to 40 C (104 F), the study shows.

One farmer had done “direct handling of a number of sick ducks and chickens in his homestead,” the summary says. One girl “bought a duckling and cared for it in her house for five days.” After the duck got sick and died, she buried it and a day later reburied it. The girl also had eaten barely-cooked eggs, the summary noted.

The outbreak in Asia has raised growing alarm in the Europe, where strains of bird flu have struck before but which remains free of the disease this year, and United States, where outbreaks of a milder strain have been confirmed in the states of Delaware and New Jersey in recent days.