Avian influenza update: more deaths reported

November 2005

A Thai man is dead and his 7-year-old son was hospitalized after they both developed symptoms of avian influenza, WHO officials said.

The boy, from Kanchanaburi Province, developed symptoms of avian influenza on Oct. 16 and was hospitalized three days later. The same day, Oct. 19, his father died of avian influenza, according to WHO.

These are the first two confirmed cases in Thailand in a year. Since the start of the outbreaks in Asia, Thailand has confirmed 19 cases, of which 13 have been fatal, according to WHO officials.

In addition, Indonesia has confirmed two additional cases of human infection with H5N1 avian influenza. The first new case occurred in a 4-year-old boy from Sumatra Island in Lampung Province. He developed symptoms on Oct. 4, was hospitalized, recovered fully and has returned home. He is the nephew of a 21-year-old man from Lampung, who also had avian influenza. Although the two cases are related and they lived in the same neighborhood, human-to-human transmission is considered unlikely, because there is a history of exposure to infected poultry, WHO officials said.

The second newly confirmed case was a 23-year-old man from Bogor, West Java. He was hospitalized and died in September. Epidemiological investigations uncovered exposure to infected poultry as the likely source of infection.

To date, Indonesia has reported seven human cases of H5N1 avian influenza. Four of these were fatal.

During the current outbreak, laboratory-confirmed human cases have been reported in four countries: Cambodia, Indonesia, Thailand and Vietnam.

Bird cases spread

Although human cases so far are confined to Asia, cases in birds have traveled to Eastern Europe, and the World Organization for Animal Health (OIE) confirmed the presence of highly pathogenic H5N1 avian influenza in samples taken from domestic birds in Turkey.

In Romania, investigations of recent poultry deaths have also identified the H5 subtype of avian influenza virus. Further testing is under way to determine the strain and whether the virus is highly pathogenic. Authorities in the two countries have undertaken control measures. WHO is sending diagnostic reagents and other supplies to support testing in national laboratories. Viruses from both outbreaks have been sent for further analysis to the Central Veterinary Laboratory Agency in Weybridge, United Kingdom, which is an OIE/FAO reference laboratory. Viruses are also being sent to WHO reference laboratories for comparison with human H5N1 isolates from Asia.

“The spread of H5N1 to poultry in new areas is of concern as it increases opportunities for further human cases to occur. However, all evidence to date indicates that the H5N1 virus does not spread easily from birds to infect humans,” WHO officials said in a press statement.

The spread of the virus to new areas has also captured the attention of the Bush administration. In a speech before the National Institutes of Health earlier this month, Bush said he asked Congress for $1.2 billion to purchase vaccine to protect 20 million Americans against avian influenza.

Bush told health officials that while there is no pandemic influenza in the United States or the world as of yet, “if history is our guide there’s reason to be concerned.”

WHO suggested that countries experiencing outbreaks in poultry should follow certain precautions, particularly during culling operations, and to monitor those with a possible exposure for a history of fever or respiratory symptoms. The early symptoms of H5N1 infection mimic those of many other common respiratory illnesses, meaning that false alarms are likely.

The WHO level of pandemic alert remains unchanged at phase 3 which means a virus new to humans is causing infections, but does not spread easily from one person to another.

Travelers to areas experiencing outbreaks of highly pathogenic H5N1 in poultry should avoid contact with live animal markets and poultry farms because large amounts of the virus can be excreted in the bird droppings, WHO officials said.

1918 pandemic’s cause

In related news, the CDC published an interim rule in the Federal Register declaring the strain of influenza responsible for the 1918 pandemic as a select agent. The agency earlier reported that the strain was a form of avian influenza.

The Mount Sinai School of Medicine, the Armed Forces Institute of Pathology and Southeast Poultry Research Laboratory determined the set of genes in the 1918 virus that made it so harmful. Prior to this study, which is published in Science, influenza experts had little knowledge of what made the 1918 pandemic so much more deadly than the 1957 and 1968 pandemics. A related article, published in Nature, describes the final three gene sequences of the 1918 influenza virus.

The 1918 pandemic killed an estimated 20 to 50 million people worldwide, including 675,000 in the United States. The pandemic’s most striking feature was its unusually high death rate among otherwise healthy people aged 15 to 34. During normal seasonal influenza outbreaks, severe complications and death are most common among the elderly and young children.

There are 41 agents and toxins listed as select agents under the Public Health Security and Bioterrorism Preparedness and Response Act of 2002.

“We’ve learned why this virus was so deadly and we know it’s easily transmitted from person to person,” said CDC director Julie Gerberding, MD. “But there is a lot we don’t know, so it’s only logical that we take immediate steps to regulate this virus as a select agent as an added way to protect the public.”

Under provisions outlined in the interim rule, anyone that possesses, uses or transfers the 1918 strain of influenza or the eight key gene regions of the 1918 virus is required to register with the CDC.

People, laboratories and other facilities that work with select agents are required to ensure that they can safely handle the virus as outlined in the CDC/NIH Biosafety in Microbiological and Biomedical Laboratories, 4th edition.

In addition, they are required to increase safeguards and security measures for the virus, including controlling access, screening personnel and maintaining records to be included in a national database with records from others registered. The Act imposes criminal and civil penalties for inappropriate use of select agents and toxins.

After the CDC’s discovery, the NIH, FDA, U.S. Department of Agriculture and Department of Defense met to decide whether the agent should be listed as a select agent.

They used four criteria to determine whether to include the 1918 strain on the select agent list: the effect on human health of exposure to the agent or toxin; the degree of contagiousness of the agent or toxin and the methods by which the agent or toxin is transferred to humans; the availability and effectiveness of pharmacotherapies and immunizations to treat and prevent any illness resulting from infection by the agent or toxin; and the needs of children and other vulnerable populations. The panel unanimously agreed that the virus warranted select agent status.

An international meeting to develop a strategy for handling H5N1 is planned this month in Geneva at the WHO headquarters.

World health leaders hope to identify the next steps for the control of avian influenza in animals and preparedness efforts for a human influenza pandemic.

For more information:

• Tumpey TM, Basler CF, Aguillar PV, et al. Characterization of the reconstructed 1918 Spanish influenza pandemic virus. Science. 2005;310:77-80.