How to reduce avian flu spread at Asian poultry markets

As recently as one month ago, authorities in Vietnam registered a further 40 outbreaks of highly pathogenic avian influenza (HPAI) in poultry.

(mashi_naz, Bigstock)
(mashi_naz, Bigstock)

As recently as one month ago, authorities in Vietnam registered a further 40 outbreaks of highly pathogenic avian influenza (HPAI) in poultry. These were the most recently reported outbreaks of 52 since August of 2020, directly affecting more than 114,000 poultry in six of the country’s eight regions.

Predominantly, these outbreaks have hit birds belonging to village or backyard flocks, and a likely source of transmission is live bird markets. While consumers in larger towns and cities may have the option to buy poultry products packaged from supermarkets, those in rural areas may have no choice other than to follow the tradition of buying live birds from the local market.

Overcoming the disease risks from such locations is a challenge. However, a new study reveals that just two relatively easy and inexpensive changes can greatly reduce infection transfer.

Two of the most effective ways to prevent the transmission of the H7N9 HPAI virus in live markets are to halt overnight stays by poultry, and to use portable testing equipment. These are the main findings of a study carried out in a live bird market in Vietnam, reports The Mandarin.

According to the researchers, many infections with this virus in humans come from chickens. The risk of transmission is increased at live bird markets, where people and poultry come together in close proximity. Key to reducing this risk are frequent monitoring and surveillance, and the researchers found this could be achieved effectively using a portable PCR device. Instead of lab testing, which can take as long as three days, the portable equipment gave a result in seven hours. Speeding up detection of the virus resulted in a faster response to any infection present.

Another finding from the modelling study revealed that banning birds from staying overnight at the market can reduce the risk of spreading the HPAI virus. Many traders said they kept unsold poultry at the market until the following day — or sometimes for several days.

Funded by the United States Agency for International Development (USAID) and the FEDER/Région Occitanie Recherche et Sociétés, the study was led by Dr. Claire Guinat of the University of Toulouse in France.

HPAI outbreaks blamed for continuing high egg prices in South Korea

Since the latest wave of HPAI hit the country in November of last year, 109 outbreaks of the disease have been confirmed in South Korean poultry flocks. A month has now elapsed since the last cases in poultry or wild species, and migratory birds have returned to their summer territories. As a result, the disease alert level has been reduced from the highest category (red) to the lowest (blue), reports Yonhap news agency.

In terms of numbers of outbreaks, the latest wave has been less impactful than the previous one in 2016-2017, when 383 outbreaks were recorded. Authorities attribute this lower number of cases, at least in part, to an amended policy of culling. Previously, only birds within 500 meters of a confirmed outbreak were culled to halt the spread of infection. In November last year, this had been extended to premises within three kilometers of an infected farm, although the limit was reduced to one kilometer in February of 2021. 

Impacts on the nation’s poultry sector of the latest HPAI wave have, however, been dramatic. Total number of birds culled between November 2020 and April of 2021 has reached 29.8 million, according to the same source. For laying hens, the population was the lowest for three years, standing at 62.1 million at the end of March. This is a drop of 15% year-on-year. As the same point, the domestic duck population was 3.92 million — a record low level and 52% lower than 12 months previously. 

In order to maintain supplies on the South Korean market, an emergency quota-free tariff on egg imports was introduced earlier this year. Up to May, the agriculture ministry  reports that 105.3 million eggs have been imported, with additional volumes of 25 million during April, and 40 million this month.

In its latest official report on the HPAI situation, South Korea has registered 14 outbreaks of HPAI linked to the H5N8 virus variant between February 17 and April 6. Involving a total of more than 1.435 million birds, according to the report to the World Organisation for Animal Health (OIE). These outbreaks occurred mainly at farms with laying hens or ducks, and one of 4,654 meat turkeys. Flocks ranged in size from 88,000-550,000 for the layers, and 9,000-25,000 for the ducks. Affected premises were located in five provinces.

Based on OIE data, the latest HPAI wave in South Korea has involved a total of almost 10.26 million poultry, comprising 22,000 mortalities and 10.24 million more culls.

Japan’s farmers urged to take action now to prevent repeat of HPAI losses  

The latest update from Japan’s agriculture ministry, dated April 30 indicates no new outbreaks of HPAI since March 13. Total outbreaks stand at 76, including 52 primary outbreaks. 

For Japan, losses of poultry from the disease since November of 2020 have reached 9.87 million, reported Japan Times last week. The HPAI virus has been detected at premises in 18 prefectures, including Chiba and Ibaraki in the Kanto region, which are the nation’s centers for poultry production. In Chiba, one-third of the laying hens — 4.56 million birds — were culled. 

As in South Korea, the outbreaks have resulted in a sharp rise in the price of eggs for consumers. And despite the easing of the disease situation, there is no sign of these falling back to pre-HPAI levels. Market price for medium-sized chicken eggs in Tokyo last week were 50% higher year-on-year at 250 yen (JPY; US$2.29) per kilo.

To avoid the return of HPAI later this year, the Japanese government is urging the country’s farmers to implement a range of measures to help exclude viruses. Key among these is security of poultry buildings to exclude rodents and other wild animals. In official investigations following recent outbreaks, these were identified as likely sources of spreading infection. Poultry owners are also called up to disinfect farm areas regularly, and to ensure that netting is undamaged.

According to Japan Times, officials are considering linking the payment of farm subsidies to compliance with these biosecurity measures.

Iraq registers new avian flu outbreaks

A second outbreak of HPAI linked to the H5N8 virus variant has been reported to the OIE by the Veterinary authority of Iraq. On April 18, the disease was found to be present in a flock of 131,600 poultry in the Baghdad-Altarmia region of the central governorate of Saladin. More than 54,000 of the birds died, and 20,000 were culled. 

Previously, there was an outbreak at another farm in the governorate in January. 

Local media report new outbreak in northern India

Earlier this month, local media reported an outbreak of HPAI at a poultry farm in the state of Punjab, reported ANI News. The affected premises is identified as the Suba Singh poultry farm in the district of Ludhiana.

Presence of the H5N8 HPAI virus was confirmed by the national laboratory. In the surrounding area, control zones were set up to prevent the further spread of infection. These apply to movements of live poultry, poultry products and feed. 

Numbers of poultry scheduled for culling are unclear. One source, Tribune, puts the total to be culled at between 31,000 and 65,000 of the 75,000 poultry at the farm. 

So far this year, Indian authorities have officially registered HPAI outbreaks linked to this virus in the states of Kerala, Haryana, Gujarat, Madhya Pradesh and Rajasthan. Poultry and/or wild birds in five states (including Punjab) have tested for the H5N1 virus subtype over the same period. 

Avian flu under control in four more Asian countries

In April, Israel’s animal health agency declared to the OIE that the HPAI situation with respect to the H5N8 virus variant had been “resolved.” This followed direct losses of more than 356,600  poultry in 12 outbreaks between October and December last year. 

In Kuwait, the most recent cases linked to the same virus subtype was confirmed on March 19. Based on official reports to the OIE, seven outbreaks occurred in the period April 8-19. Involving a total of around 714,500 breeding poultry, first to be affected was a farm in Al Jahrah in the north of the country. This was followed by six more outbreaks, all at Wafrah in the southern region of Al Ahmadi.

Recently, Iran’s animal health agency reported to the OIE that no new cases of HPAI had been detected in its poultry flocks. Latest cases linked to the H5N8 virus were in early April. Since the first outbreak in December of last year, more than 30 outbreaks were reported. Directly impacted were more than 1.3 million birds through mortality or culling.

Six outbreaks of HPAI involving the same virus subtype have been confirmed to the OIE by the veterinary authority in Nepal. Between January and mid-March of this year, a total of 25,800 poultry were involved in these outbreaks.

One new human cases of influenza A(H9N2) in China

Another person in China has tested positive for the influenza A(H9N2) virus, according to the World Health Organization.

 A 30-year-old woman from Huizhou in Guangdong province showed mild symptoms, and tested positive for the virus on April 21. This case brings to 13 the number of people in China testing positive for this virus so far this year. In the Western Pacific Region, there have been 54 cases since December of 2015. 

View our continuing coverage of the global avian influenza situation.

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