African swine fever (ASF) outbreak in India: A review of literature about the virus and its control measures (original) (raw)
2020, The Pharma Innovation Journal
African swine fever (ASF) is a highly contagious viral disease of swine causing high mortality in domestic pigs with mortality rates approaching 100%. The disease is caused by a double stranded DNA virus called as ASF virus (ASFV) and is believed to be the only member of the Asfarviridae family and genus Asfivirus. Viral entry into the host is through receptor mediated endocytosis. Although the attachment factors and specific receptors involved in the process are still unknown, macro-pinocytosis and clathrin-dependent entry mechansims have been proposed. ASFV replicates predominantly in the cytoplasm of macrophages. ASFV infection in its natural hosts is usually asymptomatic and the host remains persistently infected (PI). In contrast, AFSV infection in domestic pigs leads to lethal haemmorhagic fever and death. Wild suids and arthropod vectors of the genus Ornithodoros spp are believed to be the natural hosts of the virus. Pigs acquire the infection either through the sylvatic cycle or the domestic cycle. ASFV is endemic to Africa but due to transboundary movement, the virus has spread to other continents. India reported its first outbreak of the virus recently in the Northeastern regions of the country i.e in Assam and Arunachal Pradesh. Till the month of June, ASF has killed over 17,000 pigs in Assam and an unknown number in Arunachal Pradesh. This review throws a light into the nature of the virus, epidemiology, transmission cycle, viral entry mechanism, signs and symptoms, treatment options and preventing the spread of the disease.
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Veterinary Record, 2016
African swine fever (ASF) is a major threat to the pig industry in Europe. Since 2007, ASF outbreaks have been ongoing in the Caucasus, Eastern Europe and the Baltic countries, causing severe economic losses for many pig farmers and pork producers. In addition, the number of ASF cases in wild boar populations has dramatically increased over the past few years. Evidence supports direct contact with infectious domestic pigs and wild boars, and consumption of contaminated feed, as the main transmission routes of ASF virus (ASFV) to domestic pigs. However, significant knowledge gaps highlight the urgent need for research to investigate the dynamics of indirect transmission via the environment, the minimal infective doses for contaminated feed ingestion, the probability of effective contacts between infectious wild boars and domestic pigs, the potential for recovered animals to become carriers and a reservoir for transmission, the potential virus persistence within wild boar populations and the influence of human behaviour for the spread of ASFV. This will provide an improved scientific basis to optimise current interventions and develop new tools and strategies to reduce the risk of ASFV transmission to domestic pigs. AFRICAN swine fever (ASF) is one of the pig diseases with the highest mortality. Many ASF virus (ASFV) strains result in the death of almost 100 per cent of infected pigs. In addition to the impact on animal health and people's livelihoods, the disease can have a major impact on global trade in pigs and pork products and is a threat to global food security (EFSA 2014). ASFV is endemic in most of sub-Saharan Africa and Sardinia and, since the first case in Georgia in 2007, has been spreading through the Caucasus, Eastern Europe and the Baltic countries (see geographical regions determined according to the United Nations Statistics Division:
EFSA Journal
The European Commission requested that EFSA provide study designs for the investigation of four research domains according to major gaps in knowledge identified by EFSA in a report published in 2019: (i) the patterns of seasonality of African Swine Fever (ASF) in wild boar and domestic pigs in the EU; (ii) the epidemiology of ASF in wild boar; (iii) survival of ASF virus (ASFV) in the environment and (iv) transmission of ASFV by vectors. In this Scientific Opinion, the fourth research domain on ASFV transmission by vectors is addressed. Eleven research objectives were proposed by the EFSA working group and broader ASF expert networks, such as ASF stop, ENETWILD, VectorNet, AHAW network and the AHAW Panel Experts. Of the 11 research objectives, six were prioritised based on the following set of criteria: (1) the impact on ASF management; (2) the feasibility or practicality to carry out the study; (3) the potential implementation of study results in practice; (4) a possible short time-frame study (< 1 year); (5) the novelty of the study and (6) if it was a priority for risk managers. The prioritised research objectives were: (I) Studies on the potential vector fauna at the pig-wild boar interface and the feeding preference of blood-feeding potential vectors in ASF-affected areas; (II) Assessment of the efficacy of insect screens on indoor/outdoor pig holdings to prevent the entry of blood-sucking vectors (i.e. Stomoxys) in ASF endemic areas; (III) Assess the role of mechanical vectors in the virus transmission in ASF-affected areas; (IV) Distribution of the potential mechanical transmission vectors in ASF-affected areas of the EU; (V) ASFV transmission by synanthropic birds; and (VI) Assessment on the presence/absence of the soft tick Ornithodoros erraticus in ASF-affected areas in Europe. For each of the selected research objectives, a research protocol has been proposed considering the potential impact on ASF management and the period of 1 year for the research activities.
African swine fever: A permanent threat to Indian pigs
Veterinary World, 2020
India has 9 million pigs, of which 45% are in the North eastern (NE) states of India. Viral diseases affecting pigs are a major concern of mortality causing huge loss to the pig farmers. One such disease is African swine fever (ASF) that has already knocked the porous borders of NE states of India. ASF is a highly contagious devastating disease of pigs and wild boars causing 100% mortality. The causative agent African swine fever virus (ASFV) belongs to the genus Asfivirus, family Asfarviridae. Pig is the only species affected by this virus. Soft ticks (Ornithodoros genus) are shown to be reservoir and transmission vectors of ASFV. Transmission is very rapid and quickly engulfs the entire pig population. It is very difficult to differentiate classical swine fever from ASF since clinical symptoms overlap. Infected and in contact pigs should be culled immediately and buried deep, and sheds and premises be disinfected to control the disease. There is no vaccine available commercially. Since its first report in Kenya in 1921, the disease has been reported from the countries in Europe, Russian federation, China, and Myanmar. The disease is a threat to Indian pigs. OIE published the first report of ASF in India on May 21, 2020, wherein, a total of 3701 pigs died from 11 outbreaks (Morbidity - 38.45% and mortality - 33.89%) in Assam and Arunachal Pradesh states of India. ASF is non-zoonotic.
Serological behaviour of isolated African Swine fever virus
Archives of Virology, 1970
African swine fever, a disease originally confined to African countries, broke out in Portugal in 1957 (1). After the apparent disappearance of the virus for eighteen months, new loci of African swine fever appeared in 1960 (2), and it has since established itself as an enzootic disease.
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