While the United States has reported in excess of 2,000 human West Nile virus (WNV) cases this year as of the beginning of December and over 40,000 cases since the mosquito borne virus was first seen in the country in 1999, the South American country of Brazil has never seen a human WNV case…until now.


The World Health Organization (WHO) reported today that on 9 December 2014, the Ministry of Health of Brazil reported a case of West Nile Virus (WNV) in the state of Piauí (PI). This is the first detection of a human case of WNV infection in Brazil.

The case has been under investigation since August 2014, when the patient had the first symptoms. The infection was laboratory-confirmed on 28 November 2014. The case, who was admitted to hospital in Teresina (PI), has been discharged and will undergo rehabilitation and physical therapy to recover.

Four other people presented symptoms; however, laboratory tests ruled out WNV infection. In addition to those with symptoms, tests were performed on 18 other individuals in the area and all results were negative.

West Nile virus is an arthropod-borne virus (arbovirus) most commonly spread by infected mosquitoes. West Nile virus can cause febrile illness, encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord).

It was first detected in North America in 1999, and has since spread across the continental United States and Canada.

Most people get infected with West Nile virus by the bite of an infected mosquito. Mosquitoes become infectedwhen they feed on infected birds. Infected mosquitoes can then spread the virus to humans and other animals.

In a very small number of cases, West Nile virus has been spread through blood transfusions, organ transplants, and from mother to baby during pregnancy, delivery, or breastfeeding, according to the CDC. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page