Bushmeat is the name given to wild animals killed for food, and usually refers to African animals.

Scientists estimate that three-quarters of the newest infectious diseases in humans come from animals. For instance, the HIV virus that causes AIDS is thought to have passed from monkeys to humans. It is so deadly that 1.8m people died from AIDS in 2010 alone.

Some researchers think that other diseases found in wild animals could have the potential to cross over into humans and mutate, causing serious outbreaks of disease.

Using samples confiscated by customs officials, scientists tested five species of monkey that had been illegally imported. They found several viruses that could potentially prove harmful to humans. One of these is simian foamy virus (SFV), which seems harmless in humans so far, but some scientists think it has the potential to become deadly if it mutates and spreads easily.

The researchers say that their study didn’t include any examples of imported reptiles, birds, carnivores or other types of animals, and that they only tested a small number of samples. That means that there are potentially many more viruses entering the US in bushmeat, which could have unknown effects on the health of humans.