Nigerian health officials have declared an outbreak of Lassa fever in Nigeria. Travelers to Nigeria should avoid contact with rats, especially rat urine and feces, and keep their accommodations or campsites clean.
A large, ongoing outbreak of yellow fever in Nigeria began in September 2017. The outbreak is now spread throughout the country. Travelers going to Nigeria should receive vaccination against yellow fever at least 10 days before travel and should take steps to prevent mosquito bites while there.
There is an outbreak of Andes virus in Argentina, specifically in Chubut Province of Patagonia. Travelers to Argentina should avoid contact with rodents and their droppings (urine and feces), and avoid close contact with anyone who may be sick.