RESUMO
Babesia bigemina is a parasite endemic in different parts of the world, including Europe and the Americas. One of the few genes characterized in this species codifies for the Apical Membrane Antigen 1 (AMA-1), a trans-membrane antigen recently identified. In this research, we characterized the ama-1 gene from three Italian B. bigemina strains, two B. bigemina strains obtained from Ragusa, Sicily (ITA1 and ITA3) and a third one obtained from Benevento, Campania (ITA2). Italian sequences were compared with those of the Australian strain obtained from the Sanger Institute web site and to strains from different parts of the world. The results obtained confirmed that this newly described ama-1 gene is highly conserved among Italian and foreign strains which has implications for vaccine development.
Assuntos
Antígenos de Protozoários/metabolismo , Babesia/classificação , Babesia/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Protozoários/metabolismo , Sequência de Aminoácidos , Animais , Antígenos de Protozoários/química , Antígenos de Protozoários/genética , Clonagem Molecular , Regulação da Expressão Gênica , Proteínas de Membrana/química , Proteínas de Membrana/genética , Dados de Sequência Molecular , Proteínas de Protozoários/química , Proteínas de Protozoários/genéticaRESUMO
A multiplex PCR/DNA probe assay was used to monitor Babesia bovis, B. bigemina and Anaplasma marginale infection in cattle introduced to a Boophilus microplus-infested area in Veracruz, Mexico. Eight intact, 18-month-old, cross-bred beef cattle (four naive, Group A; four Babesia species--premunized, Group B) were immediately exposed to ticks after arrival and were clinically monitored from day 6 to day 98 post-exposure (PE) to ticks. Blood sample analysis for DNA detection by the MPCR/DNA probe assay showed that Group A animals were infected with B. bovis from day 11 up to day 22 PE, requiring treatment on days 17-20. Group B animals were detected positive to B. bovis on days 17-20, did not require treatment and remained persistently infected from days 70 to 84 PE. Treatment of Group A animals delayed the infection with B. bigemina. These animals became positive to the parasite on days 63-77 PE. In contrast, Group B animals (untreated) showed B. bigemina infection on days 21-26 and 63-84 PE. One animal was positive for A. marginale infection on days 63-66 PE, the rest of the animals became so on days 80-98 PE. All infected animals required treatment with oxytetracycline. Monitoring the triple hemoparasite infection with the MPCR/DNA probe assay provided important epidemiological information. Thus, precautionary measures can be established when cattle are moved to a babesiosis/anaplasmosis risk area.
Assuntos
Anaplasmose/prevenção & controle , Babesiose/prevenção & controle , Doenças dos Bovinos/prevenção & controle , Anaplasma/isolamento & purificação , Anaplasmose/tratamento farmacológico , Anaplasmose/epidemiologia , Animais , Babesia/isolamento & purificação , Babesia bovis/isolamento & purificação , Babesiose/tratamento farmacológico , Babesiose/epidemiologia , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/epidemiologia , Seguimentos , México/epidemiologia , Oxitetraciclina/uso terapêutico , Reação em Cadeia da Polimerase , Carrapatos/parasitologia , Meios de TransporteRESUMO
A Duplex Polymerase Chain Reaction (DPCR)/DNA probe assay was used to detect Babesia bovis and B. bigemina DNA in cattle undergoing immunization trials. Blood samples were collected from 15 non-splenectomized, 1-2 years old bulls, inoculated with 1 x 10(7) each of culture-derived B. bovis- and B. bigemina-infected erythrocytes. 15 bulls inoculated with normal erythrocytes served as a control group. All cattle were field exposed to tick-transmitted Babesia 21 days (20 animals, Group I) and 60 days (10 animals, Group II) post-inoculation (PI). After immunization, the DPCR/DNA probe assay detected B. bigemina and B. bovis parasite DNA in all inoculated animals from days 4 to 14 PI. At challenge, B. bovis DNA was detected in all control animals as early as day 8 (Group I), or day 11 (Group II) post-introduction to a tick-infested area. The immunized bulls showed B. bovis positive PCR/DNA probe signals from day 0 (Group II) and day 8 (group I), up to day 32 post-exposure to ticks. Positive B. bigemina signals were detected from day 0 (Group I) and day 8 (Group II), up to day 36 post-exposure to ticks. During challenge, it was not possible to clearly define whether the PCR/DNA probe signals detected in the blood from immunized cattle were a result of amplified DNA from the culture-derived parasites, from the tick-transmitted parasites, or both.
Assuntos
Babesia/isolamento & purificação , Babesiose/parasitologia , Doenças dos Bovinos/parasitologia , Sondas de DNA , DNA de Protozoário/sangue , Reação em Cadeia da Polimerase , Vacinas Protozoárias , Vacinação/veterinária , Animais , Vetores Aracnídeos/parasitologia , Babesia/genética , Bovinos , Eritrócitos/parasitologia , Masculino , Carrapatos/parasitologiaRESUMO
The purpose of this study was to evaluate the efficacy of light microscopy (LM) examination of blood smears and a multiplex polymerase chain reaction (MPCR) assay, in terms of their ability to detect cattle experimentally infected with Babesia bovis, Babesia bigemina, and Anaplasma marginale. Blood samples were collected from 32 intact, 1-2 year old, Holstein bulls, previous to and after simultaneous inoculation of culture-derived or field isolates of B. bovis- and B. bigemina-infected erythrocytes. To establish the triple hemoparasite infection, 16 of the bulls were also inoculated with a calf-derived isolate of A. marginale. The results showed that both tests had 100% specificity. In contrast, the sensitivities of the MPCR assay against the LM test were 93.5% and 70.9%; 96.7% and 100%; and 93.8% and 93.8% for B. bovis, B. bigemina, and A. marginale infection, respectively. The advantages and disadvantages of the MPCR assay to differentially diagnose cattle with multiple hemoparasite infection are discussed.
