To the edge and back

Print edition : December 26, 2014

A Rapid Response Team of the Animal Husbandry Department arriving at Vengal in the upper Kuttanad village of Peringara in Pathanamthitta district, on November 29. Photo: LEJU KAMAL

Burning the culled fowls. Photo: LEJU KAMAL

Duck eggs were also destroyed by putting them in the pyre. Photo: LEJU KAMAL

Another outbreak of the highly pathogenic H5N1 avian influenza, this time in Kerala, rattles public health authorities and duck farmers and freezes the poultry trade.

A SINGLE bird looked ruffled and out of place within a large flock of ducks foraging in a swathe of recently harvested paddy fields. By nightfall, its beak had started quivering and it looked truly sick and despondent.

Farmers of Kuttanad are good at spotting trouble, and K.T. Kuttappan—as rustic as his name sounds and with a family tradition of rearing ducks for a living—said that was how Kerala’s first-ever outbreak of the highly pathogenic bird flu began on November 9.

“By next morning, about 15 other birds were showing similar signs. I took one to the veterinary centre at Mannady. They wanted to inspect some more birds from the lot and came to the conclusion that it must be some kind of infection. Birds began to die one after the other. Costly tablets, injections and edible ‘powders’ were prescribed in the ensuing days, before the number of deaths came down. By then I had moved the flock to another place,” he told Frontline.

Soon, though, ducks and other birds began to die all over the place and the ranks of farmers with similar stories began to swell. The State government got its first report on November 20, according to officials. Laboratory tests done locally had raised the suspicion of a serious contagion of H5N1 avian influenza. But it was on November 24 that the State government finally got official confirmation from the High Security Animal Disease Laboratory in Bhopal—as required under the Government of India’s avian influenza action plan—that the deaths were indeed caused by the highly pathogenic avian influenza virus H5N1.

Over a dozen villages of the upper Kuttanad region, spread over three central Kerala districts of Alappuzha, Kottayam and Pathanamthitta, had by then come under the grip of the bird flu virus.

Never had Kuttappan imagined that the seemingly innocuous signs first found among his flock of ducks would spread so devastatingly and, within days, wipe out or lead to the large-scale killing of an entire population of birds being reared by farmers like him for the lucrative Christmas-New Year holiday season, as per tradition.

By early December, when Chief Minister Oommen Chandy announced that the spread of the virus was finally under control, apart from the hundreds of birds that died of H5N1 infection, nearly 2.5 lakh ducks and other poultry, within a radius of one kilometre of all affected areas in the three districts, were put to death and “destroyed scientifically” by specially equipped rapid action teams. The State government also launched an intensive awareness, surveillance and disinfection campaign around each area to ensure that the virus did not spread farther.

There were no reports of the H5N1 virus affecting humans, including those who had been in close contact with the birds. The Health Department put under observation around three lakh persons and sent its workers to over 80,000 households in the affected areas, in the initial phase. Although duck deaths continued to be reported from many other parts of Kerala, tests showed they were not caused by H5N1 virus infection, according to State Animal Husbandry Department officials.

No case of the highly pathogenic H5N1 virus infection had been reported in Kerala earlier and the Kuttanad region, famous for its distinctive pattern of rice cultivation below sea level—with the fields being prone to frequent floods as well as seawater intrusion—was perhaps the ideal place for the virus strain to begin an “invasion”.

The unique wetland ecosystem, which attracts a lot of migratory birds and tourists every year, has been under much ecological stress of late, with choked waterways and poor drainage, extreme levels of fertilizer and other toxic pollution, hostile spread of invasive plant species such as water hyacinth, loss of healthy fish populations, and proliferation of waterborne parasites and predators affecting human health.

“But duck rearing is a passion in Kuttanad, and for many farmers the birds that they nurture to adulthood are like their own children,” U. Prathibha Hari, Alappuzha district panchayat president, told Frontline. “I doubt whether outsiders can fathom the agony that we witnessed as flocks of men in protective gear caught hold of all those birds for slaughter, broke their necks, dug holes, poured kerosene and lit the fires. We saw distraught farmers following them everywhere, without gowns, gloves, goggles or boots. We saw ducklings run helter-skelter with their wings on fire. We heard distressing cries from traditional duck farmers for more compassion.”

Providing adequate compensation to farmers was crucial to the difficult task of such mass culling of all the birds within a radius of one kilometre from the affected areas. Farmers said an adult duck would fetch around Rs.300 in the open market, but the government initially announced a compensation of Rs.75 for ducklings up to two months and Rs.150 for the adult birds. On second thoughts, it was later raised to Rs.100 and Rs.200 respectively.

Kuttappan said that only about 6,000 of his flock had died of the disease, and the remaining 18,762 ducks were culled. Another farmer, C.O. Thomas, said he was going to present all his birds for culling. “I cannot let them out. Fear has gripped the area. I have to find food for them every day. Those who own the fields are reluctant to let us leave the birds there. What else should we do but kill them all?”

According to the State government, Rs.80 lakh had been disbursed as compensation until November 30, when about 50,000 more birds remained to be culled. “Distressing though it was to all concerned, the government had no other option but to go for mass culling. It was the only way we could contain the spread,” Dr V. Brahmanandan, Director of the State Animal Husbandry Department, told Frontline.

The emergence of the highly contagious and rapidly fatal H5N1 bird flu virus in 2003 and its continuing circulation in poultry and ducks in Asia and many other regions have been most worrisome for governments and scientists (“Avian epidemic”, Frontline, February 27, 2004). That it has caused so much mortality in ducks in Kerala this time is further evidence that the virus continues to mutate and evolve into highly pathogenic forms.

“Ducks have been known to be carriers of the virus and usually do not get sick because of them, though there have been exceptions, as understood from some outbreaks in Vietnam and China. But, in Kuttanad, the high mortality in ducks may indicate that the virus has mutated and its virulence has increased. Persistent mutations in the virus is a sign of danger, as it could then evolve into a subtype that can infect human beings,” Dr E. Sreekumar, a senior scientist at the Viral Disease Biology wing of the Rajiv Gandhi Centre for Biotechnology in Thiruvananthapuram, said.

According to Dr Brahmanandan, avian influenza viruses are highly contagious among poultry, and in the Kuttanad setting with free-range rearing of ducks, they can easily spread the virus from place to place and to chickens (where its repercussions are known to be lethal) and other birds. Animals like pigs can also get infected, a worrisome prospect (because pigs are susceptible to infections of both avian and human influenza viruses). This would provide a platform for a virus like the H5N1 to mutate further and turn into a form that can infect human beings. “Chances of further mutations would mean it can acquire the capability to jump from humans to humans and start another devastating killer flu pandemic,” he said.

In Kerala, the virus has so far caused sickness only in birds. But the virus is known to affect humans at times. According to the World Health Organisation (WHO), from 2003 to October 2, 2014, there were 668 confirmed cases of infection in humans, of which 393 resulted in death.

It is possible that the virus made its first appearance in the State through migratory birds, which are known reservoirs of avian influenza viruses and often may not show signs of disease. But further studies are required to confirm it, or to understand the exact role of these wild birds, said Dr C. Latha, head of the Department of Veterinary Public Health of the Kerala Veterinary and Animal Sciences University.

Though the H5N1 virus is known to be more of a lethal killer agent in chickens than in ducks, the mortality was more in the latter group of birds, more so because the infection came during the holiday season, when traditionally the duck population is much higher in the area. According to Dr Brahmanandan, while at other times the duck population would be around seven lakh, it would be around 15 lakh or more at this time of the year. This increased the chance of a virulent spread. The farmers usually make their highest profits during this period—something that would often see them through until the next season.

The outbreak of H5N1 has mainly affected ducks, but it has brought the booming poultry trade in the State to a halt. The economic impact is going to be very high, according to K.N. Noushadh, Managing Director of the Kerala State Poultry Development Corporation. “As a result of the recent events, the price of broiler chicken fell drastically, much below the production cost. The fear of virus transmission also brought to a standstill the movement of broiler chicken and eggs [from other States too]. Farmers are therefore forced to feed them and look after them well, but cannot sell them. We estimate the immediate loss in the broiler market to be Rs.100 crore.”

It is important to know the risks involved in dealing with such strains of a highly pathogenic virus to understand the logistics involved in trying to contain an outbreak, Brahmanandan said. “We were dealing with a threat that we had never faced before. First the disease had to be confirmed by the laboratory in Bhopal for the State government to make the announcement at the local level. Then we had to prepare the ground properly, make the farmers aware of the need for killing the birds en masse and also decide the compensation. Culling teams—about 70 of them, each having five or six members—had to be trained, equipped and deployed. We had to take extra care because of the waterlogged geography of the region, which ruled out the option of deep burial. That left us with only one choice—to burn the carcasses of nearly 2.5 lakh birds. We had to scrounge throughout the country for the required protective gear, which was in short supply. But we needed them fast and they could be used only once and had to be destroyed immediately after that. Finally when the gear did arrive, there were problems in airlifting all the pieces together apart from questions about their validity period,” he said.

Preventive measures

Farmers and traders are hoping that the fear of infection will recede soon. There is already a clamour for immediate measures to keep the virus at bay in future and to have early detection and warning systems and preventive measures in place.

“For now, swift control measures have helped contain the spread but long-term surveillance is a must from now on,” Dr Sreekumar said. “This time the heavy mortality in the duck population made the presence of the H5N1 virus obvious. But next time, it could be a different strain of the virus. Careful genome sequencing studies are needed to understand the origin and nature of the virus strains. The tools for such studies are now available. But only two laboratories in the country are authorised to do them, because we need good precautions while handling the H5N1 virus. Its infection in humans has a severe mortality rate of 60 per cent and its management is very difficult.”

Kerala, with its huge poultry trade and the highest (10.8 kg) per capita annual consumption of poultry meat in India, must now implement immediate biosecurity measures to reduce the risk of highly pathogenic bird flu virus infection in its farms, live bird markets and slaughterhouses, Noushadh said. It must also undertake regular screening of migratory birds. “But the most important lesson in all this lies in how we lost valuable time after the infection was detected first by the farmers, in reporting it and initiating containment measures. We must strengthen farmer-government ties to ensure that such events are reported promptly and in a transparent manner,” he told Frontline.

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