ABSTRACT
The increase in human babesiosis is of major concern to health authorities. In the USA, most of these cases are due to infections with Babesia microti, whereas in Europe B. divergens is the major cause of clinical disease in humans. Here we review the immunological and biological literature of glycosylphosphatidylinositol (GPI)-anchored merozoite proteins of human Babesia parasites with emphasis on their role in immunity, and provide some new bioinformatical information on B. microti GPI-Anchored Proteins (GPI-AP). Cattle can be vaccinated with soluble parasite antigens (SPA) of Babesia divergens that are released by the parasite during proliferation. The major component in SPA preparations appeared to be a 37â¯kDa merozoite surface protein that is anchored in the merozoite membrane by a GPI anchor. Animals could be protected by vaccination with the recombinant 37â¯kDa protein expressed in Escherichia coli, provided the protein had a hydrophobic terminal sequence. Based on this knowledge, a recombinant vaccine was developed against Babesia canis infection in dogs, successfully. In order to identify similar GPI-AP in B. microti, the genome was analysed. Here it is shown that B. microti encodes all proteins necessary for GPI assembly and its subsequent protein transfer. In addition, in total 21 genes encoding for GPI-AP were detected, some of which reacted particularly strongly with sera from B. microti-infected human patients. Reactivity of antibodies with GPI-anchored merozoite proteins appears to be dependent on the structural conformation of the molecule. It is suggested that the three-dimensional structure of the protein that is anchored in the membrane is different from that of the protein that has been shed from the merozoite surface. The significance of this protein's dynamics in parasite biology and immune evasion is discussed. Finally, we discuss developments in tick and Babesia vaccine research, and the role such vaccines could play in the control of human babesiosis.
Subject(s)
Antigens, Protozoan/immunology , Babesia microti/immunology , Babesiosis/prevention & control , Protozoan Vaccines/administration & dosage , Protozoan Vaccines/immunology , Animals , Disease Models, Animal , Dogs , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunologyABSTRACT
OBJECTIVE: Establishing seroprevalence against Bartonella and Babesia microti in arural population exposed and/or non-exposed to domestic animals in Cordoba,Colombia. METHODOLOGY: Sera samples taken from 80 people from Montería and Cereté (Córdoba department) were analysed; the population sample was chosen by non-probabilistic means. Anti-Bartonella and Babesia microti were detected by indirect immunofluorescence (IFI), (Focus Technologies, Cypres, CA, USA). RESULTS: Total anti-bartonella IgG seroprevalence was 48,7 % (39/80), 77 % being male and 23 % female. Bartonella quintana seropositivity was 45 % (36/80) and Bartonella henselae seropositivity 30 % (24/80); 21 of these individuals (26,2 %) had antibodies to both bartonellas. Babesia microti seroprevelence was 30,6 % (23/80),65 % being male patients. CONCLUSIONS: High Bartonella and Babesia seroprevelence showed that infection levels had been underestimated in Colombia. Medical and sanitary authorities on the Caribbean coast of Colombia must take measures for monitoring the distribution,propagation and identification of human populations at risk of contracting infection by these micro-organisms and also orientate diagnosis and enable suitable prevention strategies to be developed for these diseases.