African Swine Fever and its impact in India
Thousands of pigs have been culled to stop it spread in Kerala. Alarmingly ASF is an infectious disease whose incidence has increased recently in the past twenty years. It has appeared as an Emerging Infectious Disease (EID) in domestic swines
In November 2022, the Animal Husbandry Department of Kerala State confirmed the outbreak of African Swine Fever in the private pig farms at Karimannoor and Vannappuram panchayat of Idukki District. It is also said that this animal disease has been confirmed in other six districts also. The selling of pork, droppings and other items related to pigs as well as the transportation of Pigs has been banned. It’s also reported that numbers of pigs have been culled to stop dispersing of this disease.
This year, this deadly animal disease has flared in India after its outbreak in the state of Assam and Arunachal Pradesh in 2020, and in March 2021 in Mizoram. It is a highly infectious viral animal disease and “African Swine Fever Virus” is its causative agent. It is a large, icosahedral, double-stranded DNA virus. It is usually 175-215 nanometers in size and has twenty equilateral triangle-shaped sides. This virus has a genome made of DNA and also contains more than 180 genes. This species of virus belongs to the Kingdom of Bomfordvirae, Class of Pokkesviricetes, Family of Asfarviridae, and Genus of Asfivirus.
This virus infects its natural hosts which include Warthogs (Phacochoerus aethiopicus) living in open and semi-open habitats of Sub-Saharan Africa, Bushpigs (Potamochoerus larvatus/porous) of forests, and riverine vegetation cultivated areas of East and Southern Africa, Wild Boars (Sus Scrofa virus), Giant Forest Hogs (Hylochoerus meinertzhagen), Soft Ticks (Ornithodoros moubata). These animals act as vectors of this disease without any symptoms. The virus exists in the wild through a cycle of infections between ticks and wild pigs. It doesn’t cause any harm to humans or other livestock.
ASFV is the only virus having a double-stranded DNA genome figured out to be transmitted by soft ticks of arthropods. This virus inundated omnivorous, domesticated, even-toed, hoofed mammals namely swine, hogs, and domestic pigs (Sus domesticus). The mortality rates of this disease among these animals are very high, nearly 100 percent. Incubation periods of this virus vary from 4 to 19 days. It causes hemorrhagic fever. For the first few days, no symptoms are perceptible but after that, the infected pig may develop severe symptoms. Gradually they lose their normal appetites and become weak to respond to their self-immune systems. Hemorrhage becomes apparent in the ears and abdomen. They start shivering, breathing abnormally, and sometimes they cough, and their extremities turn blueish-purple. They go on depression and congenital tremors. All these symptoms are similar to the normal classical swine fever but in African Swine Fever, within a few days, the infected pig goes into a comatose state and then dies.
This African Swine Fever Virus causes a wide range of signs and lesions. This virus replicates in the infected cells’ cytoplasm, a collection of substances within a eukaryotic cell, a cell having a nucleus. The cytoplasm is enclosed by the cell membrane which is also called the Plasma membrane and it consists of a gel-like substance cytosol, the cell’s internal sub-structures organelles, and various cytoplasmic inclusions. It is about 80 percent water and is usually colorless. First, the ASF virus attacks the Plasma membrane where it encodes enzymes and proteins required for the replication and transcription of its genome. Then the process of replication takes place in the perinuclear factory of the cell. After that, through various stages of transcription, there are virions produced and the animals get infected. Due to this infection, the colorless cytoplasm turns into a blueish-purple.
This virus is enzootic in many African countries. It seems that the first outbreak of this disease occurred in 1907, it was known after ASF was first described in 1921 in Kenya. Until 1957 this virus stayed restricted in Africa. After that, there was an outbreak in Europe in 1957, and then in Cuba in 1971. Thereafter in August 2018 in China and East Asia and in August 2019 in South-East Asia, this virus smeared dangerously. It was on the 29th of April 2020 there was an outbreak in the state of Assam and Arunachal Pradesh of India. It is said that the transboundary transmission of pigs and porks from China is the main reason for this disease in India.
Though the African Swine Fever Virus is endemic to Sub-Saharan Africa, the virus was first discovered after European settlers brought pigs into areas endemic to ASFV and the rest are suffering across the globe. This virus can be transmitted directly or indirectly through contact with infected pigs, feces, or body fluids, and also by eating pork products that contain the virus. The virus may survive eleven days in pig feces, and months or years in pork products, that’s why we’ve to take biosecurity measures to stop the menace. The diagnosis is usually performed by applying an ELISA, IFAT, IPT, or IBT test, Detection of antigen using FAT, real-time PCR, or isolation of the virus from either the blood, lymph nodes, spleen, or serum of an infected pig. There is no exact treatment, only symptomatic treatments are there to cure the animal. It is claimed that Vietnam successfully produced the first vaccine against African Swine Fever on June 1, 2022. But it has proven difficult to control the spreading and transmission of this disease. Often, movement restrictions and herd depopulation are necessary to control measures because of how quickly and easily the virus spreads.
When contacted Idukki District Animal Husbandry Officer Dr Binoy P Mathew, he said that preventive measures have been taken to stop the progression of the disease according to the National Action Plan(NAP) for control, containment, and eradication of the disease. To curb the possible threat, the Department of Animal Husbandry & Dairying (DAHD), GOI has prepared a Disease Control Strategy Plan in India under the Office International Des Epizooties & FAO recommendations. NAP is a part of it. He also said that with the help of the local administration and police mercy killing, disinfecting and deep burial of those pigs have taken place. Under the directions of the District Administration, there are certain Rapid Action Task Forces to supervise the Infected Zone (IZ), The Surveillance Zone (SZ), and the Disease Free Zone (FZ).
As swines have great potential to contribute faster economic returns to the farmers, these outbreaks in India largely affect pig producers, meat processors, and other related industries of domestic and International trade. Various risk factors affect the livelihood economic/nutritional, social, and psychological status of the farmers and the country. It hampers the tourism sector by polluting the Environment and weakens the rural economy. According to the 20th livestock census, there are 9.06 million numbers of pigs in India, which is 1.7 percent of the total livestock in the country. This kind of farming provides money and nutrition for socio-economic weaker people and it’s one of the best sources for the nutrition of the tribals of India. India imports pork of $1.93 million which makes 112th largest importer in the world and exports pork of $1.61 million as the 56th exporter in the world. Due to this deadly infection, there is a million-dollar loss in the financial markets of pigs as inter-state and transboundary transportation of pigs is being hampered. In some cases compensation has been provided by the concerned state governments to the affected farmers, despite there’s great tension over it.
