December 2, 2017

Bats and SARS in China

In 2002-2003 an outbreak of SARS killed almost 800 people around the world. The virus, severe acute respiratory syndrome (SARS) is a pneumonia-like illness and was first noticed in Guangdong province, southeastern China.

Scientists found genetically similar viruses in masked palm civets (Paguma larvata) sold in Guangdong’s animal markets. It was later found that similar viruses were in horseshoe bats (Rhinolophus) in China. It was thought the deadly strain probably originated in the bats, and later passed through civets before reaching humans.

This led to sampling horseshoe bats around China. In a cave in Yunnan, scientists found a strain of the virus similar to the human version. They then spent five years monitoring the bats that lived there, collecting fresh guano and taking anal swabs.

After a lot of research virologists have shown that this single population of horseshoe bats harbours virus strains with all the genetic building blocks of the one that jumped to humans in 2002. They published the news in Nov 2017.

This leads to questions. How can a virus from bats in Yunnan travel to animals and humans around 1,000 kilometres away in Guangdong, without causing any suspected cases in Yunnan itself. Also can
the human SARS strain jump from bats to another animal, such as a civet.

The scientists have to continue their search for other bat populations that carry the same strain of virus.

In the meantime there is the worry that the deadly outbreak could reappear. The cave with the affected bats is only 1 km from a village.

The Chinese authorities have closed many markets selling animals in China since the outbreaks of SARS and other infectious diseases. I really wonder if this is effective, or enforced.

See my blogs on bushmeat in Laos :
Laos markets
Laos bushmeat,
Luang Prabang market 

These photos were all taken in northern Laos in 2007 and 2008, relatively close to the Chinese border and Yunnan!

See the main article on bats and SARS in Nature 1 Dec 2017, "Bat cave solves mystery of deadly SARS virus — and suggests new outbreak could occur".

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