Study: Climate Change May Fuel Lassa Fever Outbreaks in Africa

Researchers from the Natural History Museum in London, the University of Oxford and other scientific institutions have concluded that climate change may raise the risk of dangerous rodent-borne infections spreading. The study focused on Lassa fever, a viral disease carried by one species of African mouse and particularly common in West Africa. The findings were reported by the Daily Mail.

How many people are affected

The Africa Centres for Disease Control and Prevention says around 300,000 people may be infected with Lassa fever each year. The real number of cases could be higher, because some infections go undetected.

What the analysis showed

The scientists examined 30 years of data and found a connection between rainfall and rodent numbers. In wetter conditions the animals have more food, so they breed more, which may increase the risk of the virus passing to humans.

The model was tested against more than 6,000 Lassa fever cases in Nigeria. It accurately identified seasonal outbreaks. A rise in the number of infected young rodents was usually seen about a month before cases increased among people. The virus can also persist in rodent populations, because an infected female can pass the infection to her offspring.

Limitations

The model cannot yet accurately forecast how large future outbreaks will be. Human behaviour, how often people come into contact with rodents and how effectively the disease is detected can all affect the intensity of infection. The results therefore help pinpoint seasonal risks but do not allow precise forecasts of future case numbers.