Influenza expert Dr. Robert Webster of the St. Jude Children's Research Hospital in Memphis, Tenn., told scientists at a Singapore conference organized by the medical journal The Lancet that H5N1 is now able to survive for longer in warm, moist conditions.

Scientists had hoped that reports of avian-influenza outbreaks would slow during the summer months, as older samples of H5N1 were most transmissible during the cooler months, from fall to early spring.

Webster warned against such complacency.

"When we tested the virus in Hong Kong from 1997, the virus was killed at 37 degrees Celsius (98 Fahrenheit) in two days. The current H5N1 is still viable for six days at 37. H5N1 at room temperatures can stay (alive) for at least a week in wet conditions.

"One of the often overlooked facts about influenza is that it's more heat stable than people realize, especially under moist, damp conditions. ... Don't trust it."

As the virus becomes more resilient in warm, moist climates, such as those found in Southeast Asia, Webster warns, it is also adapting itself to water, raising the distinct and unnerving possibility that untreated water may no longer be potable.

"This means that water supplies for feeding chickens, or water supplies where people are swimming and water supplies for villages have got to be treated," he said.

Meanwhile:

-- Norfolk, England, has been suffering an avian-influenza pandemic of a different -- and less serious -- variety.

Two farms in the area have been quarantined after tests showed that both were infected with a low pathogenic variant of the H7N3 strain of avian influenza, which is different from H5N1, and not related to the current concerns of an avian-influenza pandemic.

In addition to the quarantine, 15,000 birds have been culled to prevent the spread of the virus. Last week 35,000 of the region's birds were culled following the initial reports of an outbreak.

A poultry worker at the first farm to report an outbreak has been confirmed to have been infected with conjunctivitis linked with the H7N3 strain of avian influenza, but the case is not serious -- H7N3 causes a mild illness in its sufferers and is not easily transmissible between humans.

"At this stage this is a virus which only has extremely limited implications for human health," a statement from England's Health Protection Agency said.

-- British scientists for the Health Protection Agency have published research indicating that a complete shutdown of airports and air travel would merely delay -- insignificantly -- and not halt the spread of a pandemic.

The study, published Monday by the online science journal PLoS Medicine, used a mathematical model to predict the spread of a pandemic under air-travel restrictions.

"Even if 99.9 percent of all travel could be stopped, epidemics in most cities would be delayed by no more than four months," the study concluded.

"The results here suggest that resources might be better directed at reducing transmission locally and at attempting to control outbreaks during the earliest stages of sustained human-to-human spread, when movement restrictions are likely to be a more valuable containment measure."

While the four-month window mentioned in the study may seem like adequate time to prepare for a pandemic, the already slow process of producing vaccines and inoculating sizeable populations would be further impeded by air-travel restrictions and outbreaks in infected countries.

-- A ninth farm in central Pakistan has been confirmed to have been infected with the H5N1 strain of avian influenza.

Following confirmation of the outbreak at a farm in Punjab's Pindi Bhattian district 130 miles south of Islamabad, authorities culled 16,000 birds in the area.

Pakistani Commissioner of Livestock and Animal Husbandry Mohamed Afzal said the country had been vigilant in its attempts to stem the spread of the disease and that the reporting of fresh outbreaks was an indication of the efforts made by Pakistan to identify and eradicate avian influenza.

"The discovery of the virus in various farms is due to intensified efforts by the authorities to keep a close vigil on poultry farms across the country to contain the disease," he said.

-- Egypt's last human case of avian-influenza infection has recovered, Egyptian authorities announced Tuesday, but the country should remain on bird-flu alert.

"We no longer have any human infections, which shows that the spread of the disease has come under control," Health Ministry spokesman Sayyid al-Abbasi was quoted as saying by a report on the Web site of the United Nations' Office for the Coordination of Humanitarian Affairs.

"However, the threat posed by bird flu has by no means passed. ... As long as there are still cases among poultry, we cannot let our guard down."

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