Showing papers on "Babesia published in 1992"

Detection of Babesia microti by polymerase chain reaction.

Abstract: Human babesiosis, which is caused by infection with the intraerythrocytic malarialike protozoan Babesia microti, has recently been diagnosed with increasing frequency in residents of New England. Diagnosis is difficult because of the small size of the parasite and the sparse parasitemia that is characteristic of most infections with this pathogen. We generated B. microti-specific DNA sequence information by universal primer amplification of a portion of the eukaryotic 16S-like gene; this was followed by direct DNA sequence analysis. Specific primers were synthesized on the basis of this sequence information for use in the polymerase chain reaction (PCR). The PCR-based system demonstrates a strong bias for detection of B. microti as opposed to Babesia gibsoni and does not amplify vertebrate DNA. The analytical sensitivity of the system is approximately three merozoites. Blood specimens from 12 patients with clinically diagnosed and parasitologically confirmed babesiosis from Nantucket Island, Mass., were PCR positive in a blinded test of this procedure. Thus, DNA amplification may provide an adjunct to conventional methods for the diagnosis of human babesiosis and may provide a new means of monitoring therapy or enhancing epidemiological surveillance for this emerging pathogen.

Vaccination of dogs against Babesia canis infection using parasite antigens from in vitro culture.

Abstract: Summary Groups of five dogs were vaccinated with different Babesia canis vaccine formulations. It appeared that partial protection against challenge infection was obtained when using parasite antigens from in vitro culture in combination with saponin. Protection was evident as a decrease in parasitaemia after challenge and was associated with the presence of serum antibodies against Babesia parasites. In addition, parasite antigen derived from in vitro culture supernatant exhibited more protective activity than somatic parasite antigen, in that a less marked fall of haematocrit values was found after challenge infection. The fall of haematocrit value observed in the animals immunized with somatic parasite antigen was not different from that observed in the adjuvant control group.

First documented case of human babesiosis in Sweden.

Abstract: A 34-year-old splenectomized man presented with fever, myalgia and dysuria. His condition rapidly deteriorated, he became anuric and developed severe haemolytic anaemia, thrombocytopenia and fibrinolysis. Peripheral blood smears revealed intra-erythrocytic parasites consistent with Babesia divergens in 40% of the erythrocytes. The diagnosis was confirmed by gerbil inoculation and by a significant rise in antibody titer. Blood exchange transfusion reduced the number of babesia infected erythrocytes to 1%. Parenteral therapy with a combination of quinine and clindamycin eradicated parasitaemia after 10 days of treatment and the patient rapidly improved. Renal failure necessitated haemodialysis for one month, whereafter the patient made a full recovery. Human babesiosis is a rare disease, but with a potential fatal outcome and should be considered as a diagnostic alternative in splenectomized and otherwise immunocompromised individuals with severe febrile illnesses.

Non-immunologic methods of diagnosis of babesiosis.

Abstract: The diagnosis of tick-borne diseases such as babesiosis still depends on observing the parasite in the infected erythrocyte. Microscopic observation is tedious and often problematic in both early and carrier infections. Better diagnostic methods are needed to prevent clinical disease, especially when susceptible cattle are being moved into disease enzootic areas. This study evaluates two techniques for early diagnosis of Babesia bovis infections in cattle, DNA probes specific for the organism and fluorescent probes specific for nucleic acid. The radioisotopically labeled DNA probes are used in slot blot hybridizations with lysed blood samples, not purified DNA. Thusfar, the probe is specific for B. bovis and can detect as few as 1000 B. bovis parasites in 10 microliters of blood. The specificity of the fluorescent probe depends on the characteristic morphology of the babesia in whole blood samples, as determined microscopically. The fluorescent probe detects as few as 10,000 B. bovis parasites in 10 microliters os blood. The application of each method for laboratory and field use is discussed.

Endogenous superoxide dismutase activity in two Babesia species.

Abstract: Babesia hylomysci and B. divergens were studied for superoxide dismutase (SOD) activity by enzyme assay and isoelectric focusing (IEF). In the two Babesia species, parasite-associated SOD is cyanide-insensitive and inhibited by H2O2, indicating that iron is the cofactor metal. Measurements of SOD activity from purified parasites show that the SOD activity detected in Babesia is, for the main part, due to an endogenous enzyme.

Methods of treating plasmodium and babesia parasitic infections

Abstract: Methods of inhibiting the proliferation of Plasmodium or Babesia parasites are provided by the present invention. Such methods may be useful for treating malaria and babesiosis in mammals such as humans.

rRNA-based method for sensitive detection of Babesia bigemina in bovine blood.

Abstract: Three synthetic oligonucleotide probes complementary to unique regions of Babesia bigemina small-subunit rRNA were developed for detecting the parasite in bovine blood. These probes specifically detected a parasitemia of 2 x 10(-5)% by autoradiography in less than 24 h by using a 200-microliters sample of bovine blood. These probes did not bind to total RNA or genomic DNA isolated from another closely related species, Babesia bovis, or to bovine leukocyte RNA. This method detected B. bigemina infections in calves inoculated with as few as 1,000 infected erythrocytes from the second day onward for 16 days.

Field evaluation of an exoantigen-containing Babesia vaccine in Venezuela.

Abstract: Bovine babesiosis is endemic in Venezuela, causing significant losses in highly susceptible imported cattle. Current immunoprphylatic methods include the less desirable use of live parasites. Inactivated vaccines derived from exoantigen-containing supernatant fluids of in vitro Babesia bovis and B. bigemina cultures have been developed and constitute a major improvement in vaccine safety, stability and ease of handling. Vaccination trials conducted under field conditions provide the final evaluation of a culture-derived B. bovis-B. bigemina vaccine. During a 5-year period, approximately 8,000 cattle were vaccinated and 16 clinical trials carried out in. 7 states of Venezuela Clinical, serologic and parasitologic data were collected monthly from 10% of the animals over a 2-year period. Data were also collected from a similar number of nonvaccinated control cattle. Analysis of results from these trials demonstrated a reduction in the incidence of clinical disease among vaccinated animals and complete protection against mortality among vaccinated and nonvaccinated cattle. Use of this inactivated vaccine offers the best combination od safety, potency and efficacy for thew immunoprophylatic control of bovine babesiosis.

Molecular approaches to malaria and babesiosis diagnosis.

Abstract: The development of additional methods for detecting and identifuing Babesia and Plasmodium infections may be useful in disease monitoring, management and control efforts. To preliminarily evaluate sunthetic peptide-based serodiagnosis, a hydrophilic sequence (DDESEFDKEK)was selected from published BabR gene of B. bovis. Immunization of rabbits and cattle with the hemocyanin-conjugated peptide elicited antibody responses that specifically detected both P. falciparum and B. bovis antigens 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 detection using repetitive DNA was species-specific in dot-blot formats for B. bovis DNA, and in both dot-blot and in situ formats for P. falciparum; a streamlined enzymelinked synthetic DNA assay for P. falciparum detected 30 parasites/mm(cubicos) from patient blood using either colorimetric (2-15 h color development) or chemiluminescent detection (0.5-6-min. exposures). Serodiagnostic and DNA hybridization methods may be complementary in the respective detection of both chronic and acute infections. However, recent improvements in the polymerase chain reaction (PCR) make feasible a more sensitive and uniform approach to the diagnosis of these and other infectious disease complexes, with appropriate primers and processing methods. An analysis of ribosomal DNA genes of Plasmodium and Toxoplasma identified Apicomplexa-conserved sequence regions. Specific and distinctive PCR profiles were obtained for primers spanning the internal transcribed spacer locus for each of several Plasmodium and Babesia species.

Computer Simulation of Babesia bovis (Babes) and B. bigemina (Smith & Kilborne) Transmission by Boophilus Cattle Ticks (Acari: Ixodidae)

Abstract: A computer model was developed to simulate the processes involved in transmission of the cattle fever parasites Babesia bovis (Babes) and Babesia bigemina (Smith & Kilborne) between cattle and Boophilus ticks. The model of Babesia transmission was combined with a dynamic life history model for population dynamics of the tick vectors, Boophilus microplus (Canestrini) and B. annulatus (Say). Epidemiological parameters and relationships in the model include the reduction in fecundity of infected ticks, rate of transovarial transmission, effect of cattle type and inoculation rate on infectivity of cattle, variation of infected cattle recovery rate with age of infection, inoculation rate, and species of parasite. Some parameters in the model were fitted by iterative simulations to produce realistic rates of Babesia infection in larval ticks. Comparisons of simulated and reported epidemiological data from one location in Australia indicated a reasonable level of validity for the model. Theoretical tick density thresholds for maintenance of Babesia in cattle and for inoculation of greater than or equal to 99.5% calves were determined by iterative simulations at 10 locations with B. microplus and six locations with B. annulatus. The model and transmission thresholds can serve as the basis for further simulation studies on strategies for control or eradication of babesiosis.

Haematology of experimental babesiosis and ehrlichiosis in steroid immunosuppressed horses.

Abstract: An investigation was carried out to study the haematology of steroid immunosuppressed horses experimentally infected with Babesia equi and Ehrlichia equi, separately or simultaneously. Horses infected with both pathogens showed less marked changes in their haematology than those inoculated with either pathogen separately. This appeared to result from early elimination of the more pathogenic Babesia as Ehrlichia spread through the granulocytes. The apparent suppression of Babesia by Ehrlichia is of field clinical importance and merits further investigation for its apparent useful potentials in the control of babesiosis in endemic areas.

Human babesiosis. Study of vectors

Abstract: Background Babesiosis in an entity transmitted by tick bite presented in our medium producing high morbidity and mortality in immunodepressed patients. Methods The prevalence of ticks infected with bovine Babesias was studied in a sample of 104 ticks collected from cattle for alimentation in the Sierra of the Autonomous Community of La Rioja. Results 3.84% of the ticks studied (3.3% of 89 Ixodes ricinus and 6.6% of 15 Dermacentor marginatus) presented Babesias in the hemolymph by Giemsa staining. Conclusions A sizable degree of parasitization by bovine Babesia was found in the ticks of the medium studied. Given the possibility of parasitization by these parasites, babesiosis must be included in the differential diagnosis of the febrile hemolytic conditions seen in our environment.