Where the world is currently battling with the terrible disease of COVID-19, another disease is spreading its roots in the Indian State of Assam. Since February 2020 The African Swine Fever has killed almost 13,382 pigs (as on 10 May 2020). Usually such diseases are found in wild pigs but this time it has been seen in domestic pigs as well. African Swine Fever has come from China, claims Assam. As per the reports, 60 per cent of China’s pig population have been killed by the fatal disease between 2018 and 2020. The Assam government is trying to save the state’s pig population from this viral outbreak.
What is African Swine Fever?
African Swine Fever is a viral disease, which affects the wild and domestic pigs, typically resulting in an acute haemorrhagic fever and has a Case Fatality Rate (CFR) of about 100 percent. The disease causes death of the pigs within 6-13 days of the onset of infection. ASF cannot sustain in sunlight and putrefaction , but can sustain in cold (refrigerator) for more than six months.It is caused by a large DNA virus of the Asfarviridae family, which also infects ticks of the genus Ornithodoros.
Signs of African swine fever and classical swine fever (CSF) may be similar but the ASF virus is unrelated to the CSF virus.
African swine fever is a disease listed in the World Organisation for Animal Health (OIE) Terrestrial Animal Health Code and must be reported to the OIE.
Transmission of the disease
The routes of the transmission of the disease includes direct contact with an infected or wild pig ( dead/alive), indirect contact through ingestion of contaminated material such as food waste, feed or garbage or through biological vectors such as ticks.
How did this 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. In China, the first ASF outbreak was confirmed in August 2018 and since then more than 1 million pigs have been culled in the country. In Vietnam, the ASF outbreak was confirmed in February 2019 and since then over 6 million pigs have been culled.
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. “There is a province (in Tibet) which borders Arunachal Pradesh. It could have possibly travelled from there but that is only what we suspect,” said state agriculture and animal husbandry minister Atul Bora told The Indian Express.
Late last month the Assam govt. banned the slaughter and sale of pork waiting test results of samples that were sent to the National Institute of High Security Animal Diseases (NIHSAD) in Bhopal. It was later confirmed that the samples were positive for ASF.
According to a report by World Organization for Animal Health (WOAH), the disease spread was notified in 3 countries in Europe and 23 countries in Africa.
Symptoms of the disease?
Signs and mortality rates can vary according to the virulence of the virus and the type/species of pig. The Acute forms of ASF are characterized by by high fever, depression, anorexia and loss of appetite, haemorrhages in the skin (redness of skin on ears, abdomen and legs), abortion in pregnant sows, cyanosis, vomiting, diarrhoea and death within 6-13 days (or up to 20 days). Subacute and chronic forms are caused by moderately or low virulent viruses, which produce less intense clinical signs that can be expressed for much longer periods. Mortality rates are lower, but can still range from 30-70%.
Chronic disease symptoms include loss of weight, intermittent fever, respiratory signs, chronic skin ulcers and arthritis.
Different types of pigs may have varying susceptibility to ASF virus infection. African wild suids may be infected without showing clinical signs allowing them to act as reservoirs.
Prevention and Control.
Sadly so far there is no vaccine available for the disease, but it can be prevented by preventing the healthy pigs to come in contact with the affected ones. Clinical signs can help in suspecting the disease but laboratory tests can confirm the infection.