African Swine Fever Detected in a Northeastern Province

The Cambodian authorities as well as farmers are joining hands to prevent the African swine fewer (ASF) after it was detected in a northeastern province of Cambodia since late March.

According to the Ministry of Agriculture, Forestry and Fisheries, local veterinarians and experts are closely monitoring the disease since it was reported in Somthom commune, O' Ya Dav district, Rattanakiri province where more than 400 pigs died.

Mr. Srun Pov, President of the Cambodian Animal Raisers Association, voiced his concerns over this animal epidemic. He told local media that the association is working with the authorities, especially the Ministry of Agriculture, Forestry and Fisheries to take action against its spread.

According to the World Organisation for Animal Health, ASF is a highly contagious haemorrhagic viral disease of domestic and wild pigs, which is responsible for serious economic and production losses. It is caused by a large DNA virus of the Asfarviridae family, which also infects ticks of the genus Ornithodoros.

Although signs of ASF and classical swine fever (CSF) may be similar, the ASF virus is unrelated to the CSF virus. ASF is a disease listed in the World Organisation for Animal Health Terrestrial Animal Health Code and must be reported to the OIE.

This disease is not risk to human health yet, but its epidemiology is complex and varies depending on the environment, types of pig production systems, the presence/absence of competent tick vectors, human behaviour, and the presence/absence of wild pigs. Routes of transmission can include: direct contact with infected domestic or wild pigs; indirect contact, through ingestion of contaminated material (e.g. food waste, feed, or garbage); contaminated fomites, or biological vectors (soft ticks of the genus Ornithodoros) where present.

Clinical signs and mortality rates can vary according to the virulence of the virus and the type/species of pig: including Acute forms of ASF are characterised 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, diarrhea and death within 6-13 days (or up to 20 days). Mortality rates may be as high as 100 percent. 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 percent. Chronic disease symptoms include loss of weight, intermittent fever, respiratory signs, chronic skin ulcers and arthritis. Different types of pig may have varying susceptibility to ASF virus infection. African wild suids may be infected without showing clinical signs allowing them to act as reservoirs.

The World Organisation for Animal Health said currently there is no approved vaccine for ASF. Prevention in countries free of the disease depends on implementation of appropriate import policies and biosecurity measures, ensuring that neither infected live pigs nor pork products are introduced into areas free of ASF. This includes ensuring proper disposal of waste food from aircraft, ships or vehicles coming from affected countries and policing illegal imports of live pigs and pork products from affected countries. During outbreaks and in affected countries, control of ASF can be difficult and must be adapted to the specific epidemiological situation. Classic sanitary measures may be employed including early detection and humane killing of animals (with proper disposal of carcases and waste); thorough cleansing and disinfection; zoning/compartmentalisation and movement controls; surveillance and detailed epidemiological investigation; strict biosecurity measures on farms.

Source: Agency Kampuchea Press