A web platform called SpillOver, long before COVID-19, and thanks to scientists who had worked to identify animal viruses that could potentially affect people, he had classified the risk of various viruses making the leap. A mutation that would have allowed certain viruses to pass from animals to humans. The developers hope the new tool will help public health experts and policy makers avoid future epidemics.
Jonna Mazet, epidemiologist and disease ecologist at the University of California, Davis, has led this work for more than a decade. It started with the project USAID PREDICT, which sought to go beyond well-traced influenza viruses and identify other emerging pathogens that pose a risk to humans.
Thousands of scientists have scoured more than 30 countries for animal viruses, discovering many new ones in the process. But not all viruses are equally threatening. So Mazet and his colleagues decided to create a framework for interpreting their findings. “We wanted to go beyond collecting scientific stamps, simply by finding viruses, for effective risk assessment and reduction”, he claims.
SpillOver is the first Open Virus classification tool
The team was surprised to find very little research in existence on the classification of virus threats that are currently only found in animals but are in viral families that are likely to cause disease in people.
The researchers then started from scratch, identifying 31 factors related to animal viruses (how they are transmitted), their hosts (how many and varied they are), and the environment (human population density, frequency of interaction with hosts, and more) . These are summarized in a risk score out of 155, the higher the score, the greater the likelihood of spillover.
Cornell University virologist Colin Parrish, who was not involved in the study, says the factors examined were important in previous spillovers. But he notes that the risk of crossover to other viruses may be increased by unpredictable factors that emerge later. “It’s a bit like the stock market”, He says.
The new study, published in Proceedings of the National Academy of Sciences USA, classifies 887 viruses of animal origin. Twelve known human pathogens scored the highest, with the virus causing COVID-19 in second place, just below the Lassa virus carried by rats.
Influenza would have been at the top of the list if included, Mazet says. but the flu variants are already traced elsewhere. Parrish notes that the list also omits viruses transmitted by insects and those from pets. “This is a work in progress”, He says. “I’m sure it will iterate into a more powerful tool as more information and data becomes available.”
SpillOver is publicly editable and scientists around the world are already contributing their own discoveries. Mazet hopes it will also attract the attention of public health professionals and leaders. With targeted action, Mazet says, “We can make sure we don’t have these fallout at all. Or if we do, we are ready for them, because we are keeping an eye on the situation ”.