Human babesiosis: The past, present and future

Human babesiosis is a disease transmitted by the bite of an infected tick or via blood transfusions involving contaminated blood products; in humans, it can lead to severe complications and even death, depending on the clinical history, age and health status of the affected patient. Babesiosis is caused by members of the Babesia spp., protozoan parasites whose life cycle includes sexual reproduction in the arthropod vector and asexual reproduction in the mainly mammalian host. Cases of human babesiosis have been rare, but there are increasing reports of human babesiosis associated with climatic changes affecting the geographical distribution of the parasite and tick vector, enhanced vector-human interactions and improved awareness of the disease in humans. Diagnostics and treatment options for humans are based around discoveries in veterinary research, such as point-of-care testing in cases of bovine babesiosis, and include direct diagnosis by blood smears, polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) technologies, and indirect diagnosis by ELISA, immunofluorescence tests (IFAT) and fluorescent in situ hybridisation. Treatment involves a combination of drugs such as azithromycin and atovaquone, or clindamycin and quinine, but more effective options are being investigated, including, but not limited to, trans-chalcones and tafenoquine. Improved surveillance, awareness and diagnosis, as well as advanced technologies to interrupt vector-host interactions, are crucial in managing the increased threat posed by this once-neglected disease in humans.