Question 1

A patient who reports traveling to an area where West Nile virus (WNV) is endemic presents with fever, arthralgia, and rash for the last 7 days. What initial testing is recommended to confirm a diagnosis of WNV?

A) ELISA for CSF antibodies
B) ELISA for serum IgM
C) PCR assays of CSF
D) PCR assays of serum

B

Accepted Answer

The initial testing recommended to confirm a diagnosis of West Nile virus (WNV) infection is enzyme-linked immunosorbent assay (ELISA) for serum immunoglobulin M (IgM) antibodies against WNV. CSF (cerebrospinal fluid) testing may be useful for confirming neurological complications associated with WNV, but it is not typically part of the initial diagnostic workup. Polymerase chain reaction (PCR) assays may be helpful for confirming a diagnosis of acute WNV infection in some cases, but they can be less sensitive than serologic testing early in the course of illness.

Question 2

A patient expresses concern about contracting West Nile virus (WNV) infection after a family member becomes ill with the disease. What will the provider tell this patient?&#10;A) Human hosts may become reservoirs for infection for WNV.&#10;B) Humans may transmit the virus to mosquitoes after a bite.&#10;C) Humans must be bitten by a mosquito infected by a bird.&#10;D) Human-to-human transmission is possible with this disease.

Accepted Answer

West Nile virus is primarily transmitted to humans through the bite of an infected mosquito. Mosquitoes become infected after feeding on infected birds, which are the main reservoir host of the virus. WNV is not transmitted from person to person, and although humans can become infected with the virus, they are considered dead-end hosts, meaning that they do not develop high levels of virus in the bloodstream that can be transmitted to other mosquitoes.

Deck 215: Mosquito-Borne Illnesses