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Pet owners at increased risk as deadly tick-borne disease spreads throughout Asia

Diseases carried by ticks, such as this carrier of Lyme disease, are on the rise worldwide - ARCHIVE PHOTOS
Diseases carried by ticks, such as this carrier of Lyme disease, are on the rise worldwide - ARCHIVE PHOTOS

tick-borne virus that is rapidly spreading throughout Asia has such a high death rate it should be treated  on a par with diseases such as Ebola, a Japanese virologist has warned.

The new virus – severe fever with thrombocytopenia syndrome (SFTS) – is spread by tick bites and was first identified by Chinese researchers eight years ago.

It has a death rate of 30 per cent, similar to diseases such as Crimean-Congo haemorrhagic fever, classified by the World Health Organization as having "epidemic potential".

Owners of pet cats and dogs have been warned to be especially vigilant as they carry ticks.

SFTS was first identified in Japan in 2013, when 40 patients were identified. The number of cases has risen sharply since then, with 96 in the first 11 months of this year and experts anticipating that the total will surpass 100 for the whole of 2019.

“SFTS is a tick-borne infection with a fatality rate around 30 per cent and it should be classified as a viral haemorraghic fever,” said Dr Masayuki Saijo, director of Japan’s National Institute of Infectious Diseases.

“The route of the virus infection is very similar to Ebola and the fact that the fatality rate is so high means that SFTS should be treated as a biosafety level three pathogen,” he added.

With a high mortality rate and no effective treatment available, experts are warning people to take precautions against ticks while they are in rural areas. Pets are also susceptible to carrier insects, such as the Asian longhorned tick, and owners are being cautioned to be vigilant.

“We have recently found that domestic cats and dogs show similar symptoms of the virus as humans when they are infected and the fatality rate in cats exceeds 50 per cent”, Dr Saijo told the Telegraph.

“We have identified several cases in Japan in which pet owners have been infected by their pets and at least one case in which a vet died after being bitten by an infected cat,” he said.

As well as being found in China and Japan, SFTS has now been confirmed on the Korean Peninsula, Taiwan and, last year, in Vietnam. The disease is believed to have evolved between 50 and 150 years ago and previous deaths, particularly in developing parts of east Asia, were blamed on other illnesses or were simply recorded as being from unknown causes.

The primary clinical symptoms in humans are fever, vomiting, diarrhoea, low platelet count, a low white blood cell count, elevated liver enzyme levels and, ultimately, multiple organ failure.

Most cases are reported in rural areas between March and November, with the virus believed to lie dormant in the host for between six days and two weeks before the symptoms become apparent. Anyone who finds a tick embedded in their body is being advised not to try to remove it themselves but to seek medical attention.

As of the end of October, a total of 491 people had been treated in Japan for SFTS, with 70 patients dying. It appears that the illness is particularly dangerous to older people, with 90 per cent of the recorded cases among people aged 60 or older.

The virus is carried by wild animals, primarily deer and boars in Japan, but also by hedgehogs, cattle, goats and sheep.

The institute is working on a treatment, with early indications suggesting that it can reduce fatalities by about 10 per cent, Dr Saijo said.

Experts warn, however, that other as-yet unknown viruses will inevitably emerge in the future.

“Multiple factors are contributing to the emergence or re-emergence of infectious diseases, including increasing human intrusion into the natural environment, with behavioural changes associated with expanding economic development,” said Dr Martin Perlin, a Connecticut-based doctor who contributes to the eMediHealth website.

“Viral zoonoses such as SFTS have become more prominent worldwide,” he said. “With approximately one quarter of the world’s population and a vast diversity of wild and domestic animals living in close proximity to humans, it is very likely that China has the greatest potential for the emergence of infectious diseases worldwide.

“The front-line defence against such emerging infectious diseases continues to be careful clinical observation, heightened surveillance and rapid detection,” said Dr Perlin.

While SFTS has not been recorded outside east Asia, tick-borne viruses are on the rise worldwide because of a combination of climate change and increased travel. Earlier this year a potentially deadly brain disease, tick-borne encephalitis virus, was found for the first time in the UK.

Other emerging tick-borne diseases include the Bhanja virus, first documented in India in 1974 and the Heartland virus, first seen in the central states of the United States in 2012.

Japanese authorities have been conducting education programmes in areas that have reported a high number of cases, although there have been criticisms that the authorities are not taking adequate precautions.

In 2017, a press conference at the offices of the Miyazaki Prefectural Government descended into chaos when a live tick that had been brought in to show to journalists disappeared during the proceedings. A local government official placed the insect on a piece of paper to allow photographers to take close-up images but it disappeared.

Officials searched for the tick but were unable to locate it. After the room was evacuated, two types of insecticide were sprayed on the carpet and the prefectural governor issued an apology the next day.

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