MOLECULAR APPROACHES TO MALARIA AND BABESIOSIS DIAGNOSIS

The development of additional methods for detecting and identifying Ba besia and Plasmodium infections may be useful in disease monitoring, m anagement and control efforts. To preliminarily evaluate synthetic pep tide-based serodiagnosis, a hydrophilic sequence (DDESEFDKEK) was sele cted from the published BabR gene of B. bovis. Immunization of rabbits and cattle with the hemocyanin-conjugated peptide elicited antibody r esponses that specifically defected both P. falciparum and B. bovis an tigens by immunofluorescence and Western blots. Using a dot-ELISA with this peptide, antisera from immunized and naturally-infected cattle, and immunized rodents, were specifically detected. Reactivity was weak and correlated with peptide immunization or infection. DNA-based dete ction using repetitive DNA was species-specific in dot-blot formats fo r B. bovis DNA, and in both dot-blot and in situ formals for P. falcip arum; a streamlined enzyme-linked synthetic DNA assay for P. falciparu m detected 30 parasites/mm3 from patient blood using either colorimetr ic (2-15 h color development) or chemiluminescent detection (0.5-6-min exposures). Serodiagnostic and DNA hybridization methods may be compl ementary in the respective detection of both chronic and acute infecti ons. However, recent improvements in the polymerase chain reaction (PC R) make feasible a more sensitive and uniform approach to the diagnosi s of these and other infectious disease complexes, with appropriate pr imers and processing methods. An analysis of ribosomal DNA genes of Pl asmodium and Toxoplasma identified Apicomplexa-conserved sequence regi ons. Specific and distinctive PCR profiles were obtained for primers s panning the internal transcribed spacer locus for each of several Plas modium and Babesia species.