<i>Babesia crassa</i>–Like Human Infection Indicating Need for Adapted PCR Diagnosis of Babesiosis, France
Cécile Doderer-Lang, Denis Filisetti, J Badin, Charles Delale, Victoria Clavier, Julie Brunet, Chloé Gommenginger, Ahmed Abou-Bacar, Alexander W. Pfaff
Abstract
B abesiosis is a widely distributed, tickborne, zoo- notic, parasitic disease caused by different species of the apicomplexan genus Babesia and occasionally involving human infections (1). In its vertebrate host, the parasite undergoes repeated erythrocytic cycles. Clinical manifestations in humans vary widely, ranging from asymptomatic infections to rapidly evolving and sometimes fatal infections. In Europe, symptomatic human cases are infrequently observed and occur mostly in asplenic patients, where infections can rapidly become life-threatening. The most known species in Europe are Babesia divergens and B. venatorum, which are naturally found in cattle and deer (2). In contrast, infections in the United States are predominantly attributed to the rodent parasite species B. microti in the Northeast and Midwest and to B. duncani on the Pacifi c Coast and are more frequently described in human cases (3). These cases are normally mild to moderate in immunocompetent persons but can be fatal in asplenic patients. In addition, numerous zoonotic species exist and are occasionally described in human cases (8). Given the life-threatening potential of Babesia infections, rapid and reliable diagnostic methods are needed. Results of serologic testing are often negative during the acute phase. Moreover, sensitivity and specifi city are, especially for nonclassical species, not yet well described. Direct parasite detection is therefore preferable. PCR tests are performed in some specialized laboratories. However, they are usually designed to detect the major species, notably B. divergens and B. microti. We present a case study that demonstrates the need to develop a consensus for a general molecular means of detecting Babesia.