African Swine Fever (TH)

Context: Chinese scientists have found a natural mutation in the African swine fever virus they say could be less deadly than the strain that ravaged the world’s largest pig herd in 2018 and 2019.

  • Reuters reported last month that at least two new strains of African swine fever had been found on Chinese pig farms, which appeared to be man-made.
  • The strains are causing a chronic form of African swine fever that is impacting production on sow farms, industry insiders have said.


14th Aug 2020: Meghalaya hit by African swine fever

  • Earlier in February 2020, thousands of pigs died in Assam due to African Swine Fever (ASF), which does not affect humans but can be catastrophic for pigs.
  • This is the second time (first time in Assam in Feb 2020) that an ASF outbreak has been reported in India.
  • In September 2019, the outbreak of the disease swept through pig populations in China — which is the largest exporter and consumer of pork — leading to large scale culling.
  • As a result, the prices of pork shot up by over 50 per cent in the country over pre-outbreak levels.

African Swine Fever: How did the current outbreak start?

  • As per the latest update issued by the UN Food and Agriculture Organisation (FAO), the current outbreak of ASF has affected China, Mongolia, Vietnam, Cambodia, Myanmar, the Philippines, Republic of Korea and Indonesia among others.
  • Officials believe ASF came into India through Tibet into Arunachal Pradesh and then into Assam, the state with the highest population of pigs in the country.
  • This virus can be carried by wild pigs too, so one cannot say for sure how and where exactly it entered Assam since we still have not been able to determine the route yet.
  • According to the World Organisation for Animal Health (WOAH), between 2018 and 2019, the disease spread was notified in three countries in Europe and 23 countries in Africa.

What is African Swine Fever (ASF)?

  • ASF is a severe viral disease (DNA virus) that affects wild and domestic pigs typically resulting in an acute haemorrhagic fever.
  • The disease has a case fatality rate (CFR) of about 100 percent.
  • Its routes of transmission include:
  1. Direct contact with an infected or wild pig (alive or dead),
  2. Indirect contact through ingestion of contaminated material such as food waste, feed or garbage; or
  3. Through biological vectors such as ticks.
  • The disease is characterised by the sudden deaths of pigs.
  • Classical Swine Fever (CSF) has signs which may be similar to ASF, but is caused by a different virus for which a vaccine exists.
  • As of now, there is no approved vaccine, which is also a reason why animals are culled to prevent the spread of infection.
  • ASF is lethal and is less infectious than other animal diseases such as foot-and-mouth disease.
  • Any country with a pig sector is at risk of the spread of the disease and its spread is most likely via meat arriving aboard ships and planes, which is incorrectly disposed of and by meat carried by individual travellers.

How is ASF different from swine flu?

  • Swine influenza or swine flu is a respiratory disease of pigs, which is caused by type A influenza virus that regularly causes outbreaks of influenza in pig populations.
  • While the swine flu causing virus leads to a high number of infections in pig herds, the disease is not as fatal and causes few deaths.
  • Specific swine influenza vaccines are available for pigs.
  • The swine flu viruses are spread among pigs through close contact and through contaminated objects moving between infected and uninfected pigs.
  • Further, while swine flu viruses don’t typically infect humans, cases have been reported in the past (for instance during the 2009 H1N1 pandemic).

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