Time bomb

Avian influenza has been a blight on the global agriculture industry for some time but with growing concern over the possibility of a human outbreak, international organisations are working hard to halt an epidemic.

With concern over the possibility of a bird flu pandemic reaching near hysteria amongst the global community, international efforts to prepare for a worst-case scenario are being ramped up. And, irrespective of the present scale of the situation, such measures cannot be implemented too soon. While initially dismissed as a disease that only infected birds, 1997 proved a turning a point for health observers when the first human cases were reported in Hong Kong. Since then, there have been some 130 confirmed cases of the H5N1 strain of avian flu in humans in Southeast Asia, leading to over 60 deaths.

With serious ramifications now for both agriculture and human health, the urgency being attached to the situation is understandable. Of particular concern is the virulence of the virus. “The highly pathogenic H5N1 avian influenza virus infection will cause up to 100 percent mortality in chickens or turkeys. The infection is some strains is able to cause about 80 percent mortality in other domestic species including geese and ducks,” emphasises Hualan Chen, Director of the National Avian Influenza Reference Laboratory, at the Animal Influenza Laboratory of the Ministry of Agriculture, Harbin Veterinary Research Institute. “If it is not controlled, the virus infection will be able to damage the entire poultry industry in the affected areas.”

Transmitted through the gastrointestinal tract of waterfowl such as wild ducks (who are resistant to the disease), it spreads between farms through bird droppings, contaminated water or via contaminated equipment or clothing, including cages and feed. Domestic poultry are especially vulnerable to the disease but it has also been found, less commonly, in pigs. However, unlike in cases of SARS, there are not always warning signs that a bird is infected and they can die on the same day as symptoms appear.

The virus could conceivably spread as rapidly amongst the human population. “With SARS, you showed symptoms before you became infectious, so quarantine and travel restrictions worked,” explains Peter Cordingley, spokesperson for the World Health Organisation. “With flu you can be infecting people days before you know you are sick. Add in international travel and the size of mega-cities these days and you can see the risk.”

To date, the main efforts to control avian flu around the world have generally centred on mass culling and vaccination of birds. The Chinese Government recently demonstrated its capacity for tough reactive measures by imposing strict quarantines, ordering the killing of chickens in areas with outbreaks and shutting down live poultry markets in Beijing. Overall, the authorities have culled millions of birds. Beijing also announced a significant campaign of vaccination, with plans to vaccinate as many as 14 billion birds, free of charge.

The Government has also announced plans to increase production of the poultry vaccine, punish makers of fake or bad vaccines and protect the poultry industry financially. Chinese scientists have also said they are prepared, if necessary, to produce their own version of Tamiflu, the antiviral drug that is believed to be the only available medicine effective against H5N1 in humans.

Campaign concerns

Both efforts demonstrate how deeply Beijing fears the potential health and economic effects of the virus and how urgent the situation is. Dr Shigeru Omi, Regional Director of the WHO for the Western Pacific Region, recently met with officials at the Ministries of Health, Agriculture and Foreign Affairs and visited the National Influenza Centre in Beijing, whose laboratories have helped confirm the human cases listed so far on the mainland. He left impressed by the efforts.

“On the animal front, outbreaks in poultry – once they are identified – are swiftly and aggressively contained,” he concluded. “China has carried out expansive and ambitious vaccination campaigns in poultry. On the human front, China has done a good job in identifying human cases in recent months, and in conducting the necessary laboratory tests for confirmation.”

Yet even culling and vaccination campaigns are far from flawless solutions to the problem. The authorities may have culled millions of birds, but with the result that farmers have lost hundreds of millions of birds for little compensation, making farmers less keen to preventatively slaughter animals. Meanwhile, experts are also concerned wild birds are still able to spread the disease and that the transmitted virus could combine with the poultry vaccine virus, creating a new strain of the disease. And while China has joined the race to develop a vaccine against the virus that would work in humans, Cordingley highlights the present limitations of this tactic.

“Preliminary work on developing a human vaccine against H5N1 is going on and will be very useful if there is a pandemic,” he explains. “But full-scale production will probably have to wait until the exact pandemic strain is known – which almost certainly means we will have to wait for the pandemic to start. From that point, it will take probably four to six months to get production up to speed, but even then there will not be enough vaccine to protect the six billion people in the world. A vaccine will protect a lucky minority but will not stop the virus spreading.”

But there are other, more endemic challenges ahead. “Not surprisingly, the strongest challenges are found where animal and human surveillance systems are at their weakest,” Dr Shigeru Omi emphasises. “The ability to spot animal outbreaks and possible human cases at the grassroots level is a major challenge. Of the confirmed human cases so far, [most] were not forewarned by reports of poultry outbreaks in the local community. There is, therefore, a need for a concerted and greater focus at the grassroots level – so that capacity and human resources at the community level will be strengthened, particularly in terms of awareness and surveillance.”

The food industry

A major barrier to controlling avian flu in China and many Southeast Asian nations at grassroots level is the nature of the region’s food industry. Small open-air farms are still common, with pigs, poultry and people living in close proximity to each other. Almost all of the confirmed cases of humans who died from avian flu to date had been in close daily contact with infected chickens and ducks.

“I do think that we are not only trying to fight an infectious disease, we are also trying to change traditional practices and people’s preferences,” says Juan Lubroth, Senior Officer at the Food and Agriculture Organisation of the United Nations’ (FAO) Animal Production and Health Division. “That is also a hardship. We can establish good farming practices and public awareness but it is quite difficult to implement and to get people to change mindsets that have been in place for hundreds of years.”

Hualan Chen agrees. “Open-air farms pose many difficulties for the control of avian influenza – the situation enables the domestic birds to have more chance to come into contact with wild birds which may carry and spread the H5N1 viruses,” he adds. “Farmers are now being educated to raise different animals separately – for example to keep the chickens away from waterfowls, and keep pigs away from domestic poultry. But it is difficult to make these changes in a short time.”

Wet markets, for instance, where live birds are kept in overcrowded conditions and often slaughtered in an open market, pose a significant risk. Acknowledging the problem they present, some parts of the region are already taking steps to restrict them. In Hong Kong, for example, aquatic birds have been separated from terrestrial birds in all markets. There have also been efforts to try to convert the live meat market into an abattoir-based system, with people purchasing already slaughtered and dressed poultry – although commentators suggest that it could take 20 years before this system is put into widespread effect.

The World Health Organisation (WHO) is one of the main UN bodies working on improvements to the food chain. The aim is to come up with steps that will lead to the overhaul of animal husbandry (for example, the separation of chickens, ducks and pigs on farms) and better protection of humans through reduced contact between animals and people on farms and in markets. “We recognise this will be a costly exercise, with considerable resistance from stakeholders,” says Cordingley. “But WHO’s position is that it is futile to continue to fight emerging diseases on the public health front, they have to be tackled at source. International expertise and funds will be needed. In the early days, some governments placed economic considerations over public health interests and failed to promptly report outbreaks in poultry. This delay allowed the virus to take hold. It is now entrenched and will take years and lots of money to eradicate. There has been much talk of international cooperation and exchange of information, but there has not been enough action.”

In a further bid to remedy the situation, the WHO has strengthened its relationship with the FAO and the World Organisation for Animal Health (OIE), teaming up to launch the New Worldwide Avian Influenza Network (OFFLU). OFFLU aims to improve the collaboration between reference laboratories and speed up the immediate exchange of scientific data on bird flu and animal virus strains to produce efficacious vaccines for humans that respond to specific virus characteristics.

“We have organised a formal international network on the disease to be used by all veterinarians from laboratories around the world involved with the disease,” explains Dr Bernard Vallat, Director General of the OIE. “OFFLU will be used by scientists and our organisation to share information with the WHO human Influenza Network on issues relating to the animal-human interface, particularly to provide animal virus strains to facilitate the preparation of human vaccines. It will also develop the research on avian influenza while offering veterinary expertise and new skills to member countries to assist in the control and eradication of avian flu.”

Improved communication

But exchanges of information must of course also take place at a national level, something that historically has not always been the case. “Traditionally, the health and agriculture ministries have a rocky relationship,” suggests Lubroth. “But when we are dealing with a disease that is transmissible between animals and humans it is imperative that the agriculture and health ministries work hand in hand to ensure they are giving the same public awareness messages.”

The Chinese Ministry of Health and the Ministry of Agriculture have begun the process of building bridges, establishing a cooperation mechanism to prevent and control avian influenza, setting up an inter-agency team, and launching pandemic reporting system as well as joint inspection system. A framework for cooperation was finally signed in mid October 2005, although the procedures for exchanging data have still not been agreed upon.

Dr Shigeru Omi, who recently witnessed the collaboration between the Chinese Ministry of Health and WHO in battling avian influenza, recently underlined the importance of communication to the battle against avian flu. “The strongest weapons in this war are collaboration, cooperation and the sharing of information,” he emphasised in a news conference in December. “Accurate and complete reporting about outbreaks in animals and about human cases is vital. The sharing of information must be timely, regular and global. China reported its first laboratory-confirmed case [recently]. But already, the Ministry of Health has listed virus sequences from human cases in international databases for scientists the world over to access. During my visit the Ministry of Health has agreed to share the virus isolates from two of the human cases with the WHO International Collaborating Network.

“However, human H5N1 viruses are only part of the story. To fully understand how this virus is evolving, we need viruses from outbreaks in animals. Last year, the Ministry of Agriculture shared five virus isolates. This year, it has shared virus sequence information from the Qinghai wild bird outbreaks. However, from the more than 30 reported outbreaks in animals in 2005, no viruses have been made available so far. Ministry of Agriculture officials have told me they understand the importance of sharing viruses. But time is of the essence.”

Fundamental changes

Overall, the international community is steadily firming up plans to tackle the growing problem of avian influenza, but the clock is ticking. At national level there is still a huge disparity in the organisation of efforts to control the virus from country to country. China’s campaign has seen it improve communication channels and implement culling and vaccination drives, although it is difficult to measure the success of these efforts to date. Funds from a new US$300-500 million World Bank avian flu program are now also flowing to help countries combat the deadly virus. But ultimately, the biggest challenge remains at grassroots level, and the virus may only be controlled once there are fundamental changes made to the agriculture industry.

“We have provided quite a lot of recommendations, but implementing them is a bit more difficult,” explains Lubroth. “For example, the practice of raising different species together is a formula to have a virus from one species actually jump the species barrier. It is good practice to raise species separately. But while some governments have taken our recommendations and are trying to implement that, it is not easy. Similarly with the tradition of buying live birds and taking them to your house to slaughter because they are fresh. All around the globe, not just in Southeast Asia, we tend to live with our animals, and those are not the best hygienic conditions for ourselves or our animals. There needs to be better hygiene in the way that we produce our food at the local level.”

This message, however, could take a long time to emphasise – time that, unfortunately, we may not have. “More decisive action must be taken by affected countries, civil society, the private sector and by the international community to stop bird flu in animals,” Samuel Jutzi, Director of the FAO Animal Production and Health Division, recently told an international conference on bird flu. “To stop this dangerous and devastating disease requires extraordinary political commitment, very substantial investments, concerted international cooperation and severe action at the country level. We still have a window of opportunity to stop the disease in animals. The virus has not yet re-assorted or mutated. Action is required now; there is no time to lose.”