Are rats really to be blamed for spreading disease?

• Team studies pathogens in nearly 3,000 mammal species. 
• Results suggest rats blamed because scientists study them the most.
• Study finds city rats no more skilled at hosting viruses than country rats.

Research on whether rats in the city carry more pathogens than animals in rural settings has revealed that rats might not deserve the blame they get for spreading diseases, reported Web MD.

The team studied pathogens in nearly 3,000 mammal species. 

While experts did find out that rats and other urban creatures can "host up to 10 times as many kinds of diseases", the problem is that rats are 100 times more likely to be subject of studies that examine carriers of viruses. 

This suggests that scientists might be labelling rats as major pathogen-carrier because these were the mammals that were given the most attention.

"There are plenty of reasons to expect urban animals to host more diseases, ranging from their food to their immune systems to their close proximity to humans," lead study author Gregory Albery, PhD, of Georgetown University in Washington, DC, said in a statement.

He said that the team found out that urban species did host more diseases. However, the reasons are different from what we expect.

"... the reasons for this appear to be largely associated with the way we study the ecology of disease. We've looked more at animals in our cities, so we've found more of their parasites."

After considering this factor, the study found that city rats were no more skilled at hosting viruses than country rats.

"This probably means that urban animals aren't hiding as many important novel pathogens as we might think," said Albery.