BANGKOK, Thailand -- For the first time in Thailand, a rapidly
spreading "cruel" and "devastating" virus has killed least 186 horses
by attacking the animals' lungs, causing fever and death within hours.
Thailand's security forces on April 13 guarded checkpoints on highways
to stop horses being transported across the country, and quarantine
animals infected with the African Horse Sickness (AHS) virus.
"Effective immediately, and until further notice, the U.S. Department
of Agriculture's Animals and Plant Health Inspection Service's
Veterinary Services is placing restrictions on the importation of
equine from Thailand, based on the diagnosis of African Horse Sickness
in multiple equine species of different ages and sexes," the U.S.
department announced on March 31.
A 60-day quarantine was required. The New York Animal Import Center,
located in Rock Tavern, New York, is the only quarantine location
accepting horses from AHS countries.
"Any semen or embryos from countries affected with African Horse
Sickness is prohibited," the department said on its website.
Thailand's health officials established a disease control center with
deployment teams to test suffering horses, and spray disinfectant and
insecticide in barns and stables.
A hotline was created so people could inform authorities about any
illegal transportation of horses.
International veterinarians usually take a blood sample from a live
horse, or a spleen specimen at post-mortem, to confirm AHS.
Most of the 186 horses died at the epicenter where the AHS virus
killed 162 horses in northeast Thailand's Nakhon Ratchasima province,
also known as Korat.
The first death was reported during March in that province's Pak Chong
district, said Department of Livestock Development director-general
Sorawit Thanito.
An additional 13 deaths occurred in Prachuap Khiri Khan province 50
miles south of Bangkok on the Gulf of Thailand, plus five in Chon
Buri, three in Ratchaburi, two in Phetchaburi and one in Chaiyaphum
provinces, the government-owned Thai News Agency reported on April 6.
"This disease has just occurred in Thailand. We've never had it in the
past," Mr. Sorawit said.
"We have to investigate how this virus got to Thailand," he said,
Reuters reported.
Thailand was deleted from the "AHS-Free Country" list by the
Paris-based World Organization for Animal Health on March 27 after Mr.
Sorawit reported the first 42 deaths.
"Unofficial sources report these to be race horses," said the
International Disease Monitoring unit of Britain's Department for
Environment, Food and Rural Affairs on March 31.
Thailand now faces difficulties exporting horses and other equines to
the European Union and elsewhere -- including for competition in horse
races, shows and other events.
No horses from Thailand legally traveled to the United Kingdom after
December 2019, the monitors said.
The disease can attack horses, donkeys, mules and zebras, plus camels
and dogs, according to the England-based Pirbright Institute which
develops "novel vaccines for viral diseases of livestock, and is
actively working on a promising vaccine candidate for AHS."
There is no known cure or reliable vaccine. Non-steroidal
anti-inflammatory drugs can alleviate pain or reduce fever.
"It can be spread through the blood, and infects namely the lungs,
spleen and other lymphoid tissues," the institute said.
Symptoms can include fever, a loss of appetite, and swelling around
horses' eyes, lips, cheeks, tongue and neck.
The virus is infectious but not contagious from horse to horse.
It requires transmission by tiny, two-winged flies which resemble gnats.
"AHS is spread by biting midges -- Culicoides -- and dogs can become
infected by eating contaminated horse meat," the Pirbright Institute
said.
Culicoides can also give horses severe, non-fatal skin diseases.
Most of the world's AHS cases appear in sub-Saharan Africa but also in
the Middle East, Pakistan, India, Morocco, Spain and Portugal.
"For several centuries, the devastating African Horse Sickness has
been a cruel scourge to horse owners," said the National Institutes of
Health (NIH) based in Bethesda, Maryland.
AHS has "a 70% mortality rate," it said. "The geographic distribution
of the midge vector broadens with global warming and climate change."
In the mid-1800s the virus killed almost 70,000 horses within 10 years
in South Africa.
The most deaths occurred during 1959-1963 across the Middle East and
Southwest Asia, killing more than 300,000 horses, the NIH said.
That outbreak was halted thanks to experimental vaccines and the huge
toll of dead horses, which limited the number of surviving susceptible
animals.