Wednesday March 16, 2005
Preparing for an avian flu pandemic
http://thestar.com.my/lifestyle/story.asp?file=/2005/3/16/features/10318410&sec=features
With the possibility of a flu pandemic looming, some countries are already developing their own contingency plans, reports LOH FOON FONG.
With a second nurse who cared for a bird flu patient in Vietnam having contracted the disease, scientists are now not ruling out the possibility of human-to-human transmission of the H5N1 avian flu virus.
Dr Christopher Lee: ‘Government hospitals’ preventive measures have been in place since the SARS outbreak.’
The virus, which has caused 46 deaths so far, is passed from infected poultry to humans. Health authorities fear that the virus may interact with the human flu virus and mutate into a form that can pass easily from one human to another and become a global threat.
The World Health Organisation (WHO) has estimated that from two million to over 50 million people could die in the event of a flu pandemic and urged member states to develop their own contingency plans. Based on historical patterns, influenza pandemics occur three to four times each century when new virus subtypes emerge.
In the 20th century, the great influenza pandemic of 1918/1919, which caused 40 to 50 million deaths worldwide, was followed by pandemics in 1957/1958 and 1968/1969.
The British has begun stockpiling anti-flu drugs for its population. The United States is getting ready to test a bird flu vaccine and is stockpiling both vaccines and antiviral drugs. Two million doses of vaccine are being stored in bulk form for possible emergency use, according to press reports.
Hong Kong scientists have started testing a human vaccine. China and Vietnam are also testing their own bird flu vaccines for fowls and humans. Thailand is vaccinating millions of chicken and other fowls.
As for Malaysia, Dr Ramlee Rahmat, director of the Disease Control Division of the Health Ministry, said that the nation’s human influenza preparedness plan is being worked out with the WHO and local experts and should be ready in a couple of months.
“Stockpiling of vaccines and anti-viral drugs is part of the preparedness plan that is currently being discussed at ministerial level,” he said.
Dr Ramlee said the United States and Britain have stockpiled antiviral drugs because they assume that the drugs will slow down infection in the event of a pandemic. However, he cautioned that while the anti-viral drug has its role, it only reduces the viral load and virulence but does not kill the virus.
“There is no cure for a viral infection,” he said.
He said the most important thing from the public health point of view is to be sure of the mode of spread for it will determine the sort of intervention plans needed.
Malaysia has a surveillance system for influenza-like illness (ILI) that is adopted from the WHO ILI system. Currently, all outpatient clinics in government hospitals will have to report cases of atypical pneumonia and influenza to the Health Ministry.
From outpatient records in government hospitals, less than 1% of patients suffer from flu each year and the Ministry is planning on putting 1% as the threshold.
“If the number of influenza cases increases (beyond what is) normal, we will investigate,” said Dr Ramlee.
The flu surveillance will be similar to that of Severe Acute Respiratory Syndrome (SARS): when there are confirmed cases, the Ministry will carry out active detection by looking for those who are infected through health screenings and patient isolation, he said.
Although there are a couple of cases in Vietnam and Thailand that appear to have spread via human beings, there is also the possibility that it may not happen all the time, he said.
“It is not easy for the chicken flu virus to interact with the human flu virus. There’s only a possibility. Those who are living close to chicken farms may get it. That’s where education plays an important role,” said Dr Ramlee.
“The main thing is not to get the birds infected with avian flu in the first place. By protecting the birds, you are protecting human beings,” he said.
Dr Christopher Lee, head of Hospital Kuala Lumpur’s infectious disease unit, said the atypical influenza guidelines for doctors require them to ask a patient with flu if they are bird handlers and if they are, they will also be asked if any of the birds died.
He said government hospitals’ preventive measures have been in place since the SARS outbreak.
“The avian flu is more infectious than SARS. However, as long as it is not spreading from human to human, but from bird to human, the risk of spread is lower than SARS,” he said.
The influenza vaccine currently in use worldwide protects against different strains of influenza virus. It offers no protection against avian influenza. However, the WHO recommends that all persons exposed to infected chickens or to farms under suspicion should be vaccinated with the current WHO recommended influenza vaccine. This is to avoid simultaneous infection of human influenza and avian influenza, and minimise the risk of viral gene re-assortment, which could trigger an influenza pandemic.
A Vietnamese farmer leading his ducks in Thai Binh earlier this month. While the number of bird flu cases is falling across Vietnam, Thai Binh province continues to be a worry, with increasing numbers of H5N1 avian flu virus carriers.
Datuk Dr Hawari Hussein, director-general of the Department of Veterinary Services in the Agriculture Ministry, said Malaysia is currently free of avian flu but the widespread cases in Vietnam and Thailand require Malaysia to continue to be on the alert.
“First, we try to make sure that bird flu does not come in through movement of poultry. The importation of poultry and ducks and their meat products from all infected countries is still banned,” he said. Malaysia used to import poultry and meat products from Thailand and China.
If there is an infection, the Department will move in quickly and get rid of it at the source. The department will quarantine and cull the birds so that the virus does not spread to humans, he said.
“For chickens that are not in pens, we stop movement of the fowl and we cull birds within a radius of 1km of the infected chicken. We did that in Tumpat (Kelantan) in the recent outbreak,” he said.
He said the Department is also dependent on other agencies such as the anti-smuggling unit, Customs and police in monitoring the movement of poultry into the country.
The Department has also informed commercial farmers and farmers’ associations to step up and maintain bio-security, he said.
“We tell them not to simply let anyone go into the farm because the virus can be carried through infected dung on shoes or on trucks. The movement of people, vehicle and poultry crates in their farms must be monitored. They should have some kind of system to spray the trucks, for instance,” he said.
“What we want to instil in farmers is that they do it not because the authorities will come after them if they don’t but because they know that it can be a threat to their livelihood,” said Hawari.
He said the poultry industry in Malaysia has a satisfactory hygiene level, but housing of chickens and bio-security can be improved by changing the open chicken house system to closed houses.
The closed system makes it easier to control any entry of disease because there is only one entry point for air, besides allowing for better management of waste, he said.
In the open system, the chicken houses have no walls and air flows in from the sides. In the closed system, the air is sucked out of the pen and the house is kept cool; it is believed that the chickens will grow better.
Hawari said the Department has not recommended vaccination of birds as a form of control for bird flu because no one knows how effective the vaccines are.
“Moreover, there is still a lot of discussion on whether vaccination is the best way of dealing with bird flu. Vaccination is just one of the tools for disease control,” he said.
“One of the main concerns is not only to ensure the disease is not present but also to ensure that the virus is not there – you don’t only control the clinical disease but also get rid of the virus,” he said.
“The concern is that if vaccination cannot wipe out the virus 100%, it can mask the disease,” he said.
The Malaysian Government will have to start acting fast and stockpile vaccines and drugs for humans quickly and not set their strategies mainly at the poultry level because human-to-human transmission appears to have begun.
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