Babesia duncani WA1 IgG IFA

The Babesia duncani WA1 IgG assay is used to detect antibodies due to infection of the tick-borne protozoa Babesia duncani in cases of diagnostic uncertainty or suspected chronic infection. The assay is performed by indirect fluorescent antibody (IFA) method. Titer values above the reference intervals are considered evidence of current infection or past infection (e.g. within the last year).

About Babesia:

Babesiosis is caused by a protozoan parasite that infects red blood cells and is primarily transmitted through the bite of infected ticks. Babesia microti (B. microti) is the main species that has been found to cause disease in people, and B. duncani WA1 is an important secondary cause of Babesiosis in the United States. Babesiosis is a malaria-like illness wherein erythrocytes are infected and damaged by the parasite. Many people exhibit no signs of illness. Some develop non-specific flu-like symptoms. Babesiosis can be life-threatening, particularly for individuals who are elderly or young, do not have a spleen, have a weakened immune system or other serious health conditions (e.g., liver or kidney disease). Of recent concern is the increasing occurrence of blood-transfusion associated Babesiosis. Babesia is the most common blood transfusion associated parasite, yet there is no available blood donor screening assay. When clinical signs of Babesiosis coincide with either possible exposure to ticks or blood transfusion from a donor residing in an endemic region, serological testing by IFA is commonly used to support the diagnosis of Babesiosis.

The first isolate of B. duncani was found in the state of Washington, hence the name “WA1.” Until recently it was not known that B. duncani infects individuals from many regions of the U.S. and the world, although the highest seroprevalence rates are still seen in the Pacific Northwest. Infection by B. duncani cannot be diagnosed by patient blood smears or by blood culture, nor can it be detected by Babesia microti IgG IFA. Sera from patients shown to have been infected by the tick-borne pathogens B. microti, Rickettsia rickettsii and Borrelia burgdorferi were tested and found to be negative by the Babesia duncani WA1 IgG IFA assay.