Avian Flu Diary: DEFRA On India's African Swine Fever Outbreak

#15,294

One of the major infectious disease topics of 2019 BC (Before Coronavirus) was the global spread of African Swine Fever, which emerged in China in the fall of 2018, and has subsequently spread across nearly all of Eastern Asia.

ASF is also rife in Eastern Europe and Russia (see UK: DEFRA Update On ASF In Eastern Europe/Belgium), and has been blamed for the loss of more than 25% of the world's pork supply over the past two years (see New Scientist A quarter of all pigs have died this year due to African swine fever).

Five weeks ago, in Unexplained Pig Deaths In India, we looked at initial reports of excess pig mortality in Northeastern India, and while no cause was attributed, ASF was high on our suspect list.

A week later, in India: African Swine Fever Appears To Be Confirmed In Assam, we saw local officials acknowledging ASF, but it would take more than two weeks before an OIE report would be filed (see OIE Immediate Notification May 19th).

Although ASF doesn't infect humans, it is generally 100% fatal in pigs, and there is no vaccine or treatment available. The only solution is to cull infected (or exposed) pigs.

Given the pandemic driven supply chain issues, and warnings of increased food insecurity around the world (see Poverty and food insecurity could grow dramatically as COVID-19 spreads), anything that further depletes or stresses the global food supply is a serious concern.

So far, Western Europe, Australia, and North and South America have been spared - but continued success is far from assured.

A year ago the USDA announced enhanced testing and surveillance for ASF in American pigs, in hopes of detecting - and stamping out - any infections as early as possible. Also last summer, in Nature Sci. Rpts: Risk of African Swine Fever Virus Introduction into the United States, we looked at a study that attempted to quantify the risks ASF arriving in North America.

Even before the arrival of COVID-19, getting accurate and timely reports of ASF's spread around the globe was difficult, but we seem to be getting even less information today.

Whether we are talking about ASF, avian flu, MERS-CoV, or any other infectious disease threat, the risk of being blindsided while our attention is focused elsewhere is very real. Luckily there are still agencies who remain focused on other threats.

Yesterday the UK's DEFRA (Department for Environment, Food and Rural Affairs) published an update on ASF activity in Asia, with a focus on the first outbreak in India. I've only included some excerpts from a much larger report, so follow the link to read it in its entirety.

Updated Outbreak Assessment #19
African swine fever (ASF) in Asia and Oceania

28 May 2020
Ref: VITT/1200 ASF Asia

Disease report

Since our last report on 20 May, India has officially reported eleven outbreaks of ASF in domestic pig populations. There have also been reports of ASF cases in wild boar in India, however these have not been officially reported to the OIE. Cases of ASF among wild boar have also been reported in South Korea.

Situation assessment

India has now reported eleven outbreaks of ASF, all in domestic pigs in the north-east of the country, dating back to the end of January (OIE, 2020). This information in summarised in the table below

The first three outbreaks were reported as starting on the 26 January across three districts in the state of Arunachal Pradesh. Of the 2,623 pigs involved in these outbreaks, there were 444 cases and 271 deaths.

From the end of February, through to mid-April, there were a further seven outbreaks in the neighbouring state of Assam. These outbreaks affected five different districts within the state, and a total of 7,534 pigs were involved, of which there were 3,743 reported cases and 3,421 pigs died.

At the end of April, there was another outbreak in the state of Arunachal Pradesh. This involved 763 pigs, of which 12 were cases and nine died.

In all cases, disease control measures have been applied including movement restrictions, surveillance and culling of all susceptible pigs within a 1km radius of the epicentre.

Although not officially reported to the OIE, there have also been reports in the media suggesting that wild boar deaths have been linked to these outbreaks. In Arunachal Pradesh, six carcasses of wild boar were reportedly found in a community forest, with additional unverified reports of wild boar carcasses found in East Siang and Upper Siang districts (The Hindu, 2020).

In South Korea, cases continue to be reported in wild boar, but no new cases in domestic pigs. On 27 May, eight new cases were reported in the province of Gyeonggi-Do, which surrounds the country’s capital and borders North Korea (OIE, 2020). After detecting wild boar cases outside their initial wide fenced area, South Korea have implemented third stage wide fences to try and contain the spread of ASF through wildlife. In addition, surveillance is being conducted by weekly sampling and testing of domestic pig farms within a 10km radius of each wild boar case detected (FAO, 2020).

Since our last report on 20 May, there have been no further outbreaks of ASF reported in Cambodia, China, Hong Kong, Laos, Mongolia, Myanmar, North Korea, Papua New Guinea, Philippines or Timor-Leste, though it is likely that the virus is still circulating in these areas. Taiwan still remains officially free from ASF.

The confirmation of ASF in multiple countries across Asia and Oceania, and the wide geographic range of infection found within these countries, demonstrates the potential for further spread of ASF into and within the domestic pig and wild suid populations in this part of the world.

Publicity campaigns are in place in the UK to inform the general public and discourage individuals from bringing pork products into UK. This includes targeted messages to key stakeholders such as road hauliers, hunters, pig keepers and veterinarians.

See: https://pork.ahdb.org.uk/health-welfare/health/emerging-diseases/african-swine-fever/ a central depository for information has been created http://web.oie.int/rr-europe/eng/regprog/en_asf_depository.htm.

Conclusion

The risk of ASF introduction to the UK was raised to medium in August 2018 as a result of the number of outbreaks of ASF being reported in Eastern Europe, and subsequent detection of ASF in wild boar in Belgium in September 2018.

The current risk of ASF introduction to the UK is still considered to be maintained as medium, despite the spread of ASF within Asia and Oceania.

(SNIP)

People returning from any ASF-affected areas of the world should avoid any contact with domestic pigs in commercial holdings, smallholdings or even household pet pigs. Habitats where feral pigs or wild boar exist should also be avoided. All clothing, footwear or equipment should be disinfected before entering pig areas.