What is skin rash on cattle, how dangerous is it?

Inflammatory skin disease in buffaloes and cows has the ability to spread through many ways. The disease has been present in many Asian countries, the risk of spreading to Vietnam is very high.

According to the Department of Animal Health: Lumpy skin disease (English name is Lumpy Skin Disease, abbreviated as LSD), also known as cellulite, is an infectious disease caused by a virus of the Poxviridae family in buffaloes and cows. . Viral nodular dermatitis is not contagious and does not cause disease in humans.

Leaders of the Department of Animal Health inspect and take samples for testing outbreaks in Huu Lung (Lang Son). Photo: Department of Animal Health

Transmission route is mainly through insect bites such as mosquitoes, flies, ticks; The disease can also be transmitted by transporting infected buffaloes and cows, sharing drinking troughs, feeding areas, milk, semen and by direct contact.

The disease usually occurs seasonally, mainly in the months of warm weather, when insects are most active and abundant, causing yield losses due to a sharp decrease in milk production, reduced fertility, miscarriage, skin damage, loss of weight gain, death of livestock, economic loss due to transport and trade restrictions.

Viruses that cause disease survive for a long time in the environment

The virus that causes dermatomyositis belongs to the family Poxviridae, genus Capripoxvirus, the same genus as the virus that causes chickenpox in goats and sheep.

Viruses can be killed at a temperature of 55 degrees Celsius in 2 hours, 65 degrees Celsius in 30 minutes. Virus can be recovered from skin nodules kept at -80 degrees Celsius for 10 years and virus-infected tissue cultures stored at 4 degrees Celsius for 6 months.

Viruses are sensitive to alkaline or acidic pH environments; can survive at pH = 6.6 - 8.6 for 5 days at 37oC.

Chemicals used to kill viral dermatitis include ether (20%), chloroform, formalin (1%), phenol (2% for 15 minutes), sodium hypochlorite (2 - 3%), iodine compounds (mixed with dilution 1:33), Virkon (2%), quaternary ammonium compounds (0.5%) and some cleaning agents such as sodium dodecyl sulphate.

Viral nodular dermatitis is very stable, persisting for a long time in the environment, especially in the form of dry scales; persists in necrotic skin nodules for more than 33 days, in dry scabs for up to 35 days and for at least 18 days in sun-dried skin.

The virus is sensitive to sunlight and detergents containing lipid solvents, but in dark and humid environments, such as contaminated barns, the virus can survive for months.

Symptoms of sick buffaloes and cows

Infected buffaloes and cows often have the following signs: High fever, possibly above 41 degrees Celsius, loss of appetite, weakness and emaciation. Significant reduction in lactation in lactating animals; rhinitis, conjunctivitis and excessive salivation; Swollen superficial lymph nodes (anterior shoulder, posterior femoral lymph nodes).

Scales, ulcers, scars on diseased cow skin. Photo: Department of Animal Health

Formation of nodules 2 to 5 cm in diameter, especially on the scalp, neck, legs, udders, genitals and perineum within 48 hours of the onset of the febrile reaction. These nodules are round, firm, and raised above the skin, subcutaneous tissue, and sometimes the underlying muscles.

Large nodules may become necrotic and eventually fibrotic and persist for several months; leaving scars that can be permanent.

Vesicles, gangrene, and ulcers may appear on the mucous membranes of the mouth and gastrointestinal tract as well as in the trachea and lungs.

Legs and other abdominal parts of the body, such as the holster, breast, scrotum and vulva, can become drained, making the animal unwilling to move.

Bulls can be permanently or temporarily infertile. Pregnant cows can miscarry and go into heat for several months.

Some infected animals show no symptoms but carry the virus in their blood and can transmit the disease to healthy animals through blood-sucking insects.

No specific disease vector has been identified

Animals that are sensitive to the virus of skin rash are buffaloes and cows. The rate of disease in buffaloes and cows is about 10-20%; Mortality rate is about 1-5%. The average incubation period is about 4-14 days.

Arthropods are considered to be vectors for the transmission of nodular dermatitis. Although a specific vector has not been identified, mosquitoes, biting flies and male ticks may play an important role in the transmission of the virus.

The disease is easily spread through many different routes. Graphics: Department of Animal Health

The role of disease vectors is different between different geographical areas, depending on the source and characteristics of each type of vector. Infected buffaloes and bulls can excrete the virus through semen. However, to date there is no evidence of the transmission of dermatomyositis through semen.

In addition, it is not clear whether the virus can be transmitted through contaminated food and water. Direct contact is not thought to play an important role in the transmission of the skin rash virus.

Nodules and scabs contain a relatively high amount of virus. Viruses can be isolated from these specimens for 35 days and possibly longer. The virus can be isolated from blood, saliva, eye and nasal secretions, and semen.

The virus was found in blood between 7 and 21 days after infection, with lower levels than in skin nodules at the same time of sampling.

Shedding of the virus in semen can last up to 42 days. There is also evidence of placental transmission of the virus. In some cases, carrier animals do not show clinical symptoms, but carry the virus in their blood and can transmit the disease to healthy animals through blood-sucking insects.

The disease has spread in many Asian countries

Dermatitis was first discovered and described in Zambia in 1929, then the disease has spread and circulated on almost every continent. To date, dermatomyositis is endemic in most African countries.

Map of distribution of outbreaks of bovine and buffalo dermatitis in Asia, from January 1, 2014 to July 29, 2020 (by year of appearance). Source: Department of Animal Health

Since 2012, the disease has spread rapidly to the Middle East, Southeast Europe, the Balkans, the Eurasian border, Russia and Kazzakhstan. The disease has been occurring on a large scale in Turkey, when up to 131 outbreaks were recorded in 2019.

According to information from the Food and Agriculture Organization of the United Nations (FAO), from 2013 up to now, skin rash on buffaloes and cows has occurred in a number of countries such as in Asia such as those in the United States. Middle East region, India, Bangladesh, Nepal, China.

Specifically, in West Asia and Central Asia, the disease was reported to appear since 2013 and has continued to occur since then.

In South Asia, the disease was first reported in August 2019 in India, then the disease was reported in Bangladesh in September 2019.

In India, the disease was first reported to the World Organization for Animal Health (OIE) on September 18, 2019 in Odisha state; Suspected cases were also reported between September 2019 and July 2020 in four states.

In Bangladesh, the disease was confirmed in 8 geographic units between September and December 2019; Suspected outbreaks were recorded in May – June 2020.

Officials of the Department of Animal Health check and take samples for testing outbreaks in Lang Son. Photo: Department of Animal Health

In Nepal, in July 2020, a number of sick cows with typical symptoms of the disease were detected in an easternmost province. Waiting for lab test results.

In China, the first outbreak was recorded in August 2019 in the Xinjiang region, especially in July 2020 in Guangxi province, there were 5 clusters of skin rash disease (just far from Cao Bang province). about 200 km); As of September 13, 2020, a total of 14 outbreaks have been detected in this country.