British scientists created a model that can make predictions on zoonotic diseases outbreaks using changes in population growth, climate and land use. Zoonotic diseases are the ones that originate in wildlife or livestock, including Zika and Ebola, and then jump to human hosts.
The research team led by the University College London (UCL) described the new model as "a major improvement" in the scientific community's understanding of how diseases spread from animals to humans.
The scientists said the model can help in the preparations and response to outbreaks of diseases as well as the resulting policies. It can also help lawmakers in analyzing how the initiatives will disturb the environment.
For instance, lawmakers can help assess the impacts of transforming grasslands to agricultural lands in terms of zoonotic disease transmissions.
The model also has the potential to estimate the consequences of global change on various diseases at once, added lead author Professor Kate Jones from the UCL Genetics, Evolution and Environment, in order to analyze any risks that lawmakers need to make.
Among the emerging infectious diseases, about 60 to 75 percent are considered "zoonotic events." The now-prevalent Zika and Ebola viruses came from wild animals. Bats alone carry various zoonotic viruses that can jump from animals to humans.
The Lassa fever and Rift Valley fever are also examples of zoonotic disease. These two conditions now affect thousands of people and are expected to spread due to changes in the environment.
In the study, the researchers looked into the sites of 408 Lassa fever outbreaks reported in West Africa from 1967 to 2012. The Lassa virus causes hemorrhagic fevers, which, in some cases, can become fatal.
They analyzed the gathered data along with crop yields, changes in land usage, rainfall, temperature as well as changes in behavior and health care access.
The team also looked into the Lassa virus-transmitting multimammate rat subspecies to determine its outbreak locations against ecological changes.
The model allowed the researchers to estimate how often humans and infected animal carriers are likely to make contact. It also allowed them to estimate outbreak risks.
They found that by 2070, the number of infected individuals can go from 195,000 to 406,000 due to surging population rates and climate change.
"Our approach successfully predicts outbreaks of individual diseases by pairing the changes in the host's distribution as the environment changes with the mechanics of how that disease spreads from animals to people," said the study co-lead David Redding.
The research was published in the Methods in Ecology and Evolution journal.
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