Deadly virus in Malaysia’s past shows how next Covid-19-like pandemic could be just around the corner
- In the 1990s a virus struck Malaysian pig farms, spilling over to humans and leading to disease and death. Its journey shows why we should all be worried
It was sometime in September 1998 when the first reports of a mystery disease killing pigs and humans began to surface from an intensively managed pig farm in Perak, a state in the northwest of Peninsular Malaysia.
Located in the district of Tambun, the infected farm – part of a larger pig-farming area – housed some 30,000 pigs. And spread among the farms in this area were more than 100 hectares of orchards, cultivated for additional income.
According to the local hunters and orchard workers that a team of Malaysian scientists would later speak to, pteropid fruit bats – also known as flying foxes for their long snouts and large forward-facing eyes – would swoop into the orchards at night to forage from the fruit trees, which had begun to offer a steady food supply in the face of increased destruction of their forest habitats over at least the previous decade.
The scientists noted that the pigsties on the infected farm were located close to mango, durian, rambutan and jackfruit trees – with their branches growing over the roofs of the pens, or stretching into them.
They also noticed that the pigsties, confined by low walls, extended beyond the edge of their roofs. This allowed the run-off of rainwater to bathe the pigs, but it also allowed the faeces or urine of bats, or partially eaten fruit containing their saliva, to collect inside the pens.
Unknown at the time, some of these bats were carrying a virus novel to humans. As ancient creatures that have existed for some 50 million years, these Pteropus vampyrus have evolved to become an efficient reservoir for a whole assortment of viruses without getting sick.