It is not practical to control the amount of rodents in the affected states. Therefore the best way of prevention is to keep rodents out of houses and public areas to prevent people coming into contact with infected droppings. Infected patients should also be isolated to prevent the spread of the virus (by humans to other humans). In rich countries, diseases such as Lassa fever can be easily monitored by public health organisations to prevent outbreaks. Poor countries often cannot afford these services