West Nile Virus: An Emerging Threat in Transplant Population.

West Nile virus (WNV) has become one of the new challenges for transplant programs. In addition to transmission by mosquito bite, interhuman transmission is possible through blood products or organ transplantation. Majority of WNV infections present as asymptomatic or mild febrile illness, with less than 1% of infected developing neuroinvasive disease. Many studies report naturally acquired or donor-derived WNV infections in solid-organ transplant recipients, mainly kidney, but also liver, heart, lungs and pancreas. Given the much higher risk of neuroinvasive disease (40% and even higher) based on serologic and clinical studies and increased mortality in transplant population, WNV infection should be considered in all patients presented with fever and neurological symptoms after transplantation, especially during the arbovirus transmission season.