Assuntos
Babesia/efeitos dos fármacos , Insulina/fisiologia , Putrescina/farmacologia , Ácido Selenioso/farmacologia , Transferrina/farmacologia , Animais , Babesia/crescimento & desenvolvimento , Babesia/fisiologia , Babesiose/parasitologia , Reatores Biológicos/parasitologia , Bovinos , Meios de Cultura Livres de Soro , Eritrócitos/parasitologia , Técnicas In VitroRESUMO
Babesia bovis and Babesia bigemina are causative agents of bovine babesiosis, a tick-borne disease of cattle in tropical and subtropical regions. Babesia spp. infection adversely affects cattle health and can be fatal resulting in considerable economic loss worldwide. Under endemic stability conditions, herds contain high numbers of chronically infected, asymptomatic carrier animals, in which no parasitemia is detected by microscopic blood smear examination. In addition to bovines, also water buffaloes are infected by both Babesia spp. commonly leading to a subclinical infection. The infection rate (by nPCR) and herd exposure (by IFAT) of bovines and water buffaloes reared under similar field conditions in an area of endemic stability were determined and compared. In order to optimize direct parasite detection, highly sensitive nPCR assays were developed and applied, allowing the detection of as little as 0.1 fg DNA of each Babesia pathogen. Significantly lower percentages (p<0.001) of seropositive water buffaloes compared to bovines were observed for B. bovis (71.4% vs. 98%) and B. bigemina (85% vs. 100%). Interestingly, in comparison, differences noticed between water buffaloes and bovines were considerably larger with direct parasite detection by nPCR (16.2% vs. 82.3% and 24% vs. 94.1% for B. bovis and B. bigemina, respectively). As expected, bovines subjected to monthly acaricide applications exhibited a significant lower infection rate as determined by nPCR than bovines not subjected to these measures (B. bovis 33.3% vs. 90.7%, p<0.001; B. bigemina 80% vs. 96.5%, p<0.001, for treated vs. untreated animals). Interestingly no differences between these groups were observed with respect to seropositivity, suggesting similar rates of parasite exposure (B. bovis 100% vs. 97.7%, p<0.001; B. bigemina 100% vs. 100%, p<0.001). Importantly, a significantly higher number of water buffaloes as determined by nPCR were infected when reared jointly with bovines not subjected to tick control than when reared jointly with bovines subjected to tick control (B. bovis 31.6% vs. 9.5%, p<0.01; B. bigemina 42.1% vs. 9.5%, p<0.01, for water buffaloes reared with untreated vs. treated bovines) and/or when reared without bovines (B. bovis 31.6% vs. 11.6%, p<0.01; B. bigemina 42.1% vs. 20%, p<0.01). An accumulation of seropositivity and a decline of infection rates were observed in older animals, while differences observed with regard to gender may warrant further investigation. In summary, our findings suggest that water buffaloes are much more capable to limit or eliminate Babesia infection, possibly due to a more capable immune defense. Furthermore, an increased Babesia spp. parasite reservoir of bovines seems to increase the infection rate of water buffaloes when both are reared on the same pasture.
Assuntos
Babesia bovis/fisiologia , Babesia/fisiologia , Babesiose/diagnóstico , Búfalos/parasitologia , Doenças dos Bovinos/diagnóstico , Parasitemia/veterinária , Fatores Etários , Animais , Anticorpos Antiprotozoários/sangue , Babesia/genética , Babesia/imunologia , Babesia bovis/genética , Babesia bovis/imunologia , Babesiose/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , DNA de Protozoário/genética , Doenças Endêmicas/veterinária , Feminino , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Masculino , Parasitemia/diagnóstico , Reação em Cadeia da Polimerase/normas , Reação em Cadeia da Polimerase/veterinária , Prevalência , Sensibilidade e Especificidade , Fatores SexuaisRESUMO
The molecular mechanisms involved during the infection of Rhipicephalus microplus midgut cells by Babesia bigemina are of great relevance and currently unknown. In a previous study, we found a voltage-dependent anion channel (VDAC)-like protein (BmVDAC) that may participate during parasite invasion of midgut cells. In this work, we investigated BmVDAC expression at both mRNA and protein levels and examined BmVDAC localization in midgut cells of ticks infected with B. bigemina at different times post-repletion. Based on the RT-PCR results, Bmvdac expression levels were significantly higher in infected ticks compared to uninfected ones, reaching their highest values at 24h post-repletion (p<0.0001). Similar results were obtained at the protein level (p<0.0001). Interestingly, BmVDAC immunolocalization showed that there was an important differential expression and redistribution of BmVDAC protein between the midgut cells of infected and uninfected ticks, which was more evident 24h post-repletion of infected ticks. This is the first report of BmVDAC upregulation and immunolocalization in R. microplus midgut cells during B. bigemina infection. Further studies regarding the function of BmVDAC during the infection may provide new insights into the molecular mechanisms between B. bigemina and its tick vector and could result in its use as an anti-tick and transmission-blocking vaccine candidate.
Assuntos
Babesia/fisiologia , Regulação da Expressão Gênica/fisiologia , Rhipicephalus/metabolismo , Canais de Ânion Dependentes de Voltagem/metabolismo , Animais , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Rhipicephalus/microbiologia , Regulação para Cima , Canais de Ânion Dependentes de Voltagem/genéticaRESUMO
Rangeliosis is a disease which affects dogs in Brazil, caused by a piroplasm known as Rangelia vitalii. This disease causes a lot of clinico-pathological features, including the coagulation disorders associated with bleeding. The cause of these changes has not yet been determined. Considering the association of purinergic system and hemostasis this study aimed to evaluate the activity of enzymes that hydrolyze ATP, ADP and AMP; and deamination of adenosine in platelets from dogs experimentally infected with R. vitalii. For this study, 12 healthy young dogs (females) were used, separated in two groups. Group A (n=5) were uninfected controls, and group B were experimentally infected with R. vitalii (n=7). After being inoculated with R. vitalii-infected blood, animals were monitored by blood smear examinations, which showed intra-erythrocytic forms of the parasite after five days post-inoculation (PI). Blood samples were collected to quantitate and separate platelets (Day 0, 12 and 21 PI) and to measure the enzymatic activities (Day 12 and 21 PI). The activity of NTPDase, 5'-nucleotidase and adenosine deaminase (ADA) was measured in platelets. A reduction (P<0.01) in the number of platelets was observed in R. vitalii-infected blood at Days 12 and 21 PI. At Day 12 PI, a reduction (P<0.01) in the hydrolysis of ATP, ADP and AMP, and deamination of adenosine was observed in dogs infected with R. vitalii. At Day 21 PI the ADA activity remained decreased, unlike the activity of NTPDase which increased (P<0.05). Based on these results we can conclude that ATP, ADP and AMP hydrolysis and adenosine deamination were altered in platelets of R. vitalii-infected dogs. Considering the importance of the purinergic system in hemostasis, it is believed that those changes contribute to the coagulation disorders and bleeding observed in R. vitalii-infected dogs and discussed in this manuscript.
Assuntos
Adenosina Desaminase/sangue , Babesia/fisiologia , Babesiose/veterinária , Plaquetas/enzimologia , Doenças do Cão/sangue , Nucleotidases/sangue , Adenosina/metabolismo , Difosfato de Adenosina/metabolismo , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Babesiose/sangue , Babesiose/enzimologia , Transtornos da Coagulação Sanguínea/parasitologia , Transtornos da Coagulação Sanguínea/veterinária , Brasil , Desaminação , Doenças do Cão/enzimologia , Doenças do Cão/parasitologia , Cães , Feminino , Hemorragia/parasitologia , Hemorragia/veterinária , Hidrólise , Contagem de Plaquetas/veterináriaRESUMO
We investigated the interaction of Rhipicephalus microplus midgut cells with Babesia bigemina sexual stages using a proteomic approach. A polypeptide from the R. microplus midgut that binds to proteins from B. bigemina sexual stages was identified and sequenced. Combining 2D overlay and tandem mass spectrometry (MS/MS) techniques, we determined that this polypeptide corresponds to a mitochondrial voltage-dependent anion-selective channel (VDAC). The vdac gene encoding the sequenced polypeptide was identified and sequenced. This is the first report of a VDAC-like protein in R. microplus, and a possible role for this protein in the B. bigemina infection process is suggested.
Assuntos
Babesia/fisiologia , Rhipicephalus/parasitologia , Canais de Ânion Dependentes de Voltagem/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Trato Gastrointestinal/citologia , Trato Gastrointestinal/parasitologia , Regulação da Expressão Gênica/fisiologia , Dados de Sequência Molecular , Proteômica , Reprodução/fisiologia , Rhipicephalus/citologia , Canais de Ânion Dependentes de Voltagem/genéticaRESUMO
Babesia bigemina infections were investigated in four genetic groups of beef cattle and in Rhipicephalus (Boophilus) microplus engorged female ticks. Blood samples and engorged female ticks were collected from 15 cows and 15 calves from each of the following genetic groups: Nelore, Angus x Nelore, Canchim x Nelore, and Simmental x Nelore. Microscopic examination of blood smears and tick hemolymph revealed that merozoites of B. bigemina (6/60) as well as kinetes of Babesia spp. (9/549) were only detected in samples (blood and ticks, respectively) originated from calves. PCR-based methods using primers for specific detection of B. bigemina revealed 100% infection in both calves and cows, regardless the genetic group. Tick infection was detected by nested-PCR amplifications showing that the frequency of B. bigemina was higher (P<0.01) in female ticks collected from calves (134/549) than in those collected from cows (52/553). The frequency of B. bigemina was similar in ticks collected from animals, either cows or calves, of the four genetic groups (P>0.05).
Assuntos
Vetores Artrópodes/parasitologia , Babesia/isolamento & purificação , Babesiose/veterinária , Doenças dos Bovinos/parasitologia , Rhipicephalus/parasitologia , Infestações por Carrapato/veterinária , Animais , Babesia/fisiologia , Babesiose/diagnóstico , Babesiose/epidemiologia , Babesiose/parasitologia , Brasil/epidemiologia , Cruzamento , Bovinos , Doenças dos Bovinos/diagnóstico , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/genética , DNA de Protozoário/sangue , Feminino , Hemolinfa/parasitologia , Merozoítos/fisiologia , Reação em Cadeia da Polimerase , Infestações por Carrapato/parasitologiaRESUMO
Babesia parasites are intraerytrocytic Protozoa that infect wide range of domestic and wild animals and occasionally man causing babesiosis (piroplasmosis). Babesiosis also known in cattle as tick fever or red water fever is most important arthropod-borne disease of bovinae ungulates worldwide with areas of Africa, Asia, South and Central America, Australia and finally Europe. Since Smith and Kilborne had first described potential role of ticks in spread of piroplasmosis within animals, only United States till end of 50 of XX century eradicated the disease from the continent. In other, especially African countries, the problem seems to be of great economic importance. In this review all species of Babesia known to date to be infective to cattle are described with emphasis on geographical distribution of piroplasmosis, tick vector and pathogenicity of particular species and strains.
Assuntos
Babesia/classificação , Babesiose/epidemiologia , Babesiose/veterinária , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/prevenção & controle , África/epidemiologia , Animais , Vetores Aracnídeos/parasitologia , Ásia/epidemiologia , Austrália/epidemiologia , Babesia/fisiologia , Babesiose/parasitologia , Babesiose/prevenção & controle , Bovinos , Doenças dos Bovinos/parasitologia , América Central/epidemiologia , Europa (Continente)/epidemiologia , Humanos , Prevalência , Especificidade da Espécie , Controle de Ácaros e Carrapatos , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/veterinária , Carrapatos/parasitologia , Estados Unidos/epidemiologia , ZoonosesRESUMO
The present paper reports the occurrence of natural co-infection of Babesia caballi and Encephalitozoon-like microsporidia in the tick Anocentor nitens. Engorged females of ticks, collected from a naturally B. caballi-infected horse, were incubated at 27 degrees C and relative humidity over 83%. After a 6-day incubation period, Giemsa-stained smears prepared from hemolymph were examined microscopically under oil immersion. B. caballi infected ticks were dissected and samples of midgut tissue were examined by transmission electron microscopy, through which free sporokinetes were seen in the cytoplasm of gut epithelial cells. In addition, Encephalitozoon-like microsporidia were observed inside the parasitophorous vacuoles in the same cell in which sporokinetes of B. caballi were found and also in some neighbour cells. They presented different morphological stages, suggesting a sequential phases of development.
Assuntos
Babesia/fisiologia , Encephalitozoon/fisiologia , Ixodidae/microbiologia , Ixodidae/parasitologia , Animais , Babesia/isolamento & purificação , Babesia/ultraestrutura , Babesiose/parasitologia , Babesiose/transmissão , Babesiose/veterinária , Sistema Digestório/microbiologia , Sistema Digestório/parasitologia , Sistema Digestório/ultraestrutura , Encephalitozoon/isolamento & purificação , Encephalitozoon/ultraestrutura , Feminino , Doenças dos Cavalos/parasitologia , Doenças dos Cavalos/transmissão , Cavalos , Ixodidae/ultraestrutura , Estágios do Ciclo de Vida , Microscopia Eletrônica de TransmissãoRESUMO
Babesia bigemina, a causative agent of bovine babesiosis, is transmitted from one bovine to another only by infected ticks. The life cycle of B. bigemina includes a sexual phase in the tick host; however, molecules from sexual stages of any Babesia species have not been characterized. This is the first report of the induction of sexual stages of any Babesia species in vitro, free of tick antigens. Intraerythrocytic parasites were cultured in vitro for 20h using an induction medium. Extraerythrocytic parasites were first seen 3h post induction; elongated stages with long projections appeared at 6h post induction and by 9h they paired and fused to form larger stages. Round zygotes appeared 20h post induction. Moreover, by using Percoll gradients, sexual stages were purified free of contaminating intraerythrocytic stages. Purified parasites were used to generate polyclonal antibodies, which specifically bound to antigens expressed in sexual stages induced in vitro, but not to antigens expressed in intraerythrocytic stages. Importantly, these antibodies specifically identified sexual stages from midguts of female Boophilus microplus ticks fed on infected cattle.
Assuntos
Vetores Aracnídeos/parasitologia , Babesia/fisiologia , Babesiose/transmissão , Doenças dos Bovinos/transmissão , Ixodidae/parasitologia , Animais , Anticorpos Antiprotozoários/análise , Especificidade de Anticorpos , Antígenos/análise , Babesia/genética , Babesia/imunologia , Babesiose/imunologia , Bovinos , Doenças dos Bovinos/imunologia , DNA de Protozoário/análise , Eritrócitos/parasitologia , Feminino , Imunofluorescência/métodos , Estágios do Ciclo de Vida/fisiologia , Ploidias , Infestações por Carrapato/parasitologia , Zigoto/fisiologiaRESUMO
Three hundred and fifteen engorged female Boophilus microplus ticks (weight 210-250 mg) naturally infected with Babesia sp., in the Mexican tropics were monitored for egg production. Haemolymph samples were taken from each tick on the 5th day to the 16th day after collection to detect and estimate the infection with Babesia sp. kinetes. All ticks were held in darkness at 27+/-1.5 degrees C and 85-86% relative humidity. The infection rate of Babesia sp. was 20.3% (64/315). Fifteen ticks were considered heavily infected and 49 lightly infected. The pre-oviposition periods were 3.17+/-0.37, 3.18+/-0.25 and 3.17+/-0.25 days for heavily infected, lightly infected and uninfected, respectively (P>0.05). The numbers of eggs laid on the first day of oviposition were 252+/-53, 235+/-37, 54+/-23 for heavily infected, lightly infected and uninfected, respectively. There was a statistically significant difference between infected (heavily and lightly) and uninfected (P<0.05) ticks. Oviposition periods were 9.60+/-0.81, 9.50+/-0.72 and 9.36+/-0.48 days for heavily infected, lightly infected and uninfected, respectively (P>0.05). The average egg production of heavily infected, lightly infected and uninfected female ticks was 2640+/-103, 2574+/-123 and 2841+/-170 (P>0.05), respectively. These data imply that there is an adaptative tolerance between Babesia sp., and B. microplus under field conditions in the Mexican tropics.
Assuntos
Vetores Aracnídeos/parasitologia , Babesia/fisiologia , Oviposição , Carrapatos/parasitologia , Análise de Variância , Animais , Vetores Aracnídeos/fisiologia , Babesiose/parasitologia , Bovinos , Feminino , Hemolinfa/parasitologia , México , Carrapatos/fisiologia , Clima TropicalRESUMO
Propagation of Babesia bigemina in "in vitro" erythrocyte cultures resulted in the appearance of the sexual stage of the parasite, characterized by cytoplasmic projections and microtubules. These morphologically distinct parasites were found to adhere to each other, with later fusion of their membranes. No nuclear fusion was observed. The ultrastructure of the sexual stages was described.
Assuntos
Babesia/fisiologia , Eritrócitos/parasitologia , Células Germinativas/ultraestrutura , Organelas/ultraestrutura , Animais , Babesiose/parasitologia , Bovinos , Citoplasma/ultraestrutura , Células Germinativas/fisiologia , Membranas Intracelulares/fisiologia , Membranas Intracelulares/ultraestrutura , Fusão de Membrana , Microscopia Eletrônica , Microtúbulos/ultraestrutura , Organelas/fisiologiaRESUMO
Live frozen vaccines containing Babesia bovis, Babesia bigemina or Anaplasma centrale were prepared using glycerol as cryoprotectant and stored in liquid nitrogen. The viability of the vaccines was tested inoculating calves 1 h (n = 12), 2 h (n = 12), 12 h (n = 6) and 24 h (n = 6) after thawing. Babesia bovis and A. centrale were detected in thin and/or thick blood smears in all vaccinated calves; however, 1 of 12 calves inoculated 1 h after thawing and 3 of 6 calves inoculated 24 h after thawing did not develop a B. bigemina parasitaemia. The longer post-thawing durability of frozen vaccines cryoprotected with glycerol compared with those cryoprotected with dimethyl sulfoxide, presented by other authors, will extend their use under field conditions.
Assuntos
Anaplasma/imunologia , Babesia/imunologia , Vacinas Bacterianas/normas , Criopreservação , Vacinas Protozoárias/normas , Anaplasma/fisiologia , Anaplasmose/prevenção & controle , Animais , Babesia/fisiologia , Babesiose/prevenção & controle , Bovinos , Doenças dos Bovinos/prevenção & controle , Feminino , Glicerol , Vacinação/veterináriaRESUMO
Engorged females (EF) of Boophilus microplus tick were collected from Hereford, Criolla and Nelloreheifers of three different herds to study the influence of natural babesial infection on the following biological parameters of the EF: engorgement weight, preoviposition period, minimal egg incubation period, egg hatching and Reproductive Efficiency Index. No detrimental consequences to the reproduction of EF carrying babesial infection were found when compared with those EF in which no kinetes of Babesia were detected. Even the groups of EF most highly parasitized (21 to 110 kinetes per microscope field of hemolymph) showed biological values considered as normal, suggesting the existence of adaptive tolerance between B. microplus and the Babesia protozoa under field conditions.