A point of care vertical flow assay for the direct detection of Babesia microti and the serodiagnosis of Lyme disease. - Babesia microti is a parasite that is transmitted by the same species of ticks that transmit Lyme disease. It is
the causative agent of babesiosis, a disease with a wide array of clinical presentations that can range from an
asymptomatic carrier state in some otherwise healthy individuals to causing fatal infection in others. Most
cases of severe disease that result in hospitalization occur in individuals with underlying health issues such as
immune suppression and lack of a spleen. However, individuals of greater than 50 years of age are also at risk
factor for severe infection, and severe infections have been seen in younger individuals as the disease
becomes more prevalent. It is clear that not all of the factors that predispose someone to severe infection are
known. As with all tick transmitted diseases, the incidence and geographical distribution of babesiosis has
been increasing steadily over the past 20 years. B. microti can also be spread from mother to child during birth,
and to transfusion recipients through transfusion with infected blood. It is one of the most common causes of
transfusion transmitted infections reported to the FDA in the US. It is also a common co-infection with Lyme
disease, and the impact of coinfection on the course of babesiosis and Lyme disease is currently unknown.
Unlike anaplasmosis, another common coinfection with Lyme disease, the therapies used to treat Lyme
disease will not impact babesiosis, and vice versa. Accurate diagnosis is necessary for appropriate therapy to
be applied for each infection. As with most infectious diseases, early treatment can prevent the progression to
severe disease. There are currently no rapid diagnostic assays available for babesiosis. As it is transmitted by
the same ticks as Lyme disease, and is a common coinfection, we propose the development of a point of care
assay capable of supporting the diagnosis of both Lyme disease and babesiosis. We have previously
developed a point of care, multiplex, vertical flow serodiagnostic assay for Lyme disease that has the same
sensitivity and specificity of the currently used central lab two-tier testing paradigm, but can be performed in 15
minutes at the site of patient care. In the current proposal, we will add an antigen capture assay to this platform
to directly detect B. microti simultaneously with serodiagnosis of Lyme disease at the point of care. This
antigen capture assay will provide direct proof of B. microti infection, while the serodiagnostic arm will provide
support for the clinical diagnosis of Lyme disease. For this we propose two aims, 1) Derive high affinity
monoclonal antibodies to serve as capture-reporters for Babesia microti secreted antigen 1, and 2)
Development of a combined vertical flow assay for Lyme disease serology and Babesia antigen detection. This
assay will fill a critical unmet need for rapid assays to support the diagnosis of tick-transmitted diseases at the
point-of-care and improve patient outcomes through earlier antimicrobial interventions.
