RESUMO
It was investigated how many cattle become infected with Trypanosoma vivax by subcutaneous (SC), intramuscular (IM) and intravenous (IV) routes, using the same syringe and needle from an animal with acute T. vivax infection. Besides, the T. vivax viability in 109 injectable veterinary drugs (antibiotics, antiparasitics, reproductive hormones, vitamin complex and derivatives, vaccines, anaesthetics, anti-inflammatory/antipyretics, antitoxics). In the field assay, four groups were performed: T01, T02 and T03 animals that received saline solution with the same syringe and needle contaminated with T. vivax via SC, IM and IV routes, respectively, and T04 control animals that received only saline solution with the same syringe and needle IV. In the laboratory, drugs had their pH measured and T. vivax viability verified. The number of cattle infected with T. vivax via SC (3/20) was lower (P ≤ 0.05) compared to via IM (9/20), which was lower (P ≤ 0.05) compared to IV (15/20). The solution pH did not influence T. vivax viability. In 44% (48/109) of the products, T. vivax remained viable regardless of time, stooding out that in 100% of oxytocins the protozoan was verified, at some evaluation times. The mean of T. vivax quantified in foot-and-mouth and brucellosis vaccines and in doramectin-based products were higher (P ≤ 0.05) than found in blood + saline solution.
Assuntos
Doenças dos Bovinos , Tripanossomíase Africana , Tripanossomíase Bovina , Animais , Bovinos , Doenças dos Bovinos/prevenção & controle , Seringas , Trypanosoma vivax , Tripanossomíase Africana/veterináriaRESUMO
Amitraz is an acaricide that is widely used in veterinary medicine to control the cattle tick Rhipicephalus microplus. However, controversy exists in the literature regarding the resistance of R. microplus to this product. The present work provides an update on the acaricidal efficacy of amitraz (Triatox®, 12.5 % amitraz) after 15 years without its use on a property. Two in vivo (bovines treated with amitraz and submitted to tick counts, n = 20 animals) and one in vitro (adult immersion test, n = 40 ticks) assays were performed to determine product efficacy. The efficacy of the commercial formulation tested in the first in vivo trial ranged from 14.1 to 47.0%, and in the second from 3.6 to 35.1%, for the 28 days of the experiments. Efficacy for the in vitro trial was 47.38%. The dose recommended by the manufacturer of the product did not cause mortality to most of the ticks of this strain, and efficacy/resistance was not reverted or modified after 15 years (estimated 60 tick generations).
Assuntos
Acaricidas/farmacologia , Doenças dos Bovinos/tratamento farmacológico , Rhipicephalus/efeitos dos fármacos , Infestações por Carrapato/veterinária , Toluidinas/farmacologia , Acaricidas/uso terapêutico , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Feminino , Larva/efeitos dos fármacos , Masculino , Rhipicephalus/crescimento & desenvolvimento , Infestações por Carrapato/tratamento farmacológico , Infestações por Carrapato/parasitologia , Toluidinas/uso terapêuticoRESUMO
Although co-infections of Trypanosoma vivax, Anaplasma spp., and Babesia spp. have been reported, knowledge gaps remain that need to be addressed. The present study evaluated the efficacy of enrofloxacin (7.5 mg/kg) against A. marginale in naturally infected cattle and cattle experimentally co-infected with T. vivax by observation of the variation in A. marginale parasitemia and packed cell volume (PCV) for 39 days. Bovines were distributed into two groups, each with six calves: T01 = animals immunosuppressed with dexamethasone and with latent anaplasmosis; T02 = animals immunosuppressed with dexamethasone, with latent anaplasmosis and experimentally co-infected with T. vivax on day 0 (D0). Animals of both groups were immunosuppressed with dexamethasone and received enrofloxacin (7.5 mg/kg) whenever mean values of parasitemia for A. marginale were ≥ 5% per group. Cattle of group T02 were also treated with isometamidium chloride (0.5 mg/kg) on D25. On D17 and D22 to D28 of the study, there was a higher (P ≤ 0.05) A. marginale parasitemia in animals of T02 than in those of T01. Animals of T01 required one enrofloxacin treatment to decrease A. marginale parasitemia, while those from T02 needed five treatments. From D5 to D37 of study, the mean values of PCV for calves from T02 were lower (P ≤ 0.05) than that for calves from T01. In conclusion, bovines co-infected T. vivax needed four more treatments with enrofloxacin to reduce A. marginale parasitemia and keep PCV values within reference standards.
Assuntos
Anaplasmose , Doenças dos Bovinos , Enrofloxacina/uso terapêutico , Parasitemia , Tripanossomíase Africana/veterinária , Anaplasma marginale , Anaplasmose/tratamento farmacológico , Animais , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/parasitologia , Tamanho Celular , Coinfecção/parasitologia , Coinfecção/veterinária , Parasitemia/tratamento farmacológico , Parasitemia/veterinária , Trypanosoma vivax , Tripanossomíase Africana/tratamento farmacológicoRESUMO
Bovine trypanosomosis has been spreading in Brazil. In the present study, we evaluated the spatial distribution, prevalence and risk factors of this disease in the state of Goiás, Brazil, and performed both molecular and phylogenetical analyses of Trypanosoma vivax. A total of 4049 blood samples were collected from cattle for a period of 2 years. The parasitological diagnosis was performed using the Woo method and a questionnaire was administered to the farmers to document risk factors associated with the disease in the herd. Positive samples were DNA sequenced and compared to GenBank codes. The prevalence of T. vivax was 8.84%, occurring on 24 ranches only in dairy cattle and mainly in the central and southern portions of the state. The acquisition of new animals infected with T. vivax and the administration of exogenous oxytocin to cows using the same syringe and needle were the main associated factors (P ≤ 0.05). After an outbreak, milk production decreased by 39.62%. The presence of biting flies (tabanids, Haematobia irritans and Stomoxys calcitrans) was not a risk factor (P > 0.05) for the occurrence of T. vivax. The epidemiological data demonstrate the importance of restricting the practice of auctions as well as eliminating the use of exogenous oxytocin in animals during milking. The samples tested by polymerase chain reaction were positive for T. vivax and were genetically homologous with T. vivax found in different states of Brazil and west Africa based on the 18S rRNA gene.
Assuntos
Trypanosoma vivax , Tripanossomíase Bovina/epidemiologia , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , DNA de Protozoário , Surtos de Doenças/veterinária , Patologia Molecular , Prevalência , RNA Ribossômico 18S/genética , Fatores de Risco , Trypanosoma vivax/genética , Trypanosoma vivax/isolamento & purificaçãoRESUMO
The aim of the present study was to compare the infection capacity of Trypanosoma vivax experimentally inoculated through different routes in calves naturally infected with latent Anaplasma marginale. On Day 0 of the study, 25 calves (breed: Girolando) were divided into five groups. The first four groups of five calves each received approximately 1 × 106 trypomastigotes of T. vivax through the intradermal, subcutaneous, intramuscular and intravenous routes. Another five animals remained unaffected to serve as A. marginale naturally infected controls. The study of T. vivax was performed on all calves from D+1 to D+30 using the Woo, Brener and blood smear techniques. PCR was performed on Days +1, +3, +4, +5, +28, +29 and + 30. The results indicated that T. vivax was capable of infecting and developing the disease in the calves independent of the inoculation route. A positive correlation was found between T. vivax and rectal temperature (P ≤ 0.05) and a negative correlation was seen between the protozoan and globular volume (P ≤ 0.05). Latent A. marginale in the calves acted as co-infection for T. vivax. Jaundice was seen only in calves with a high parasitemia by A. marginale. Therefore, in areas with the confirmed presence of T. vivax in bovines, this protozoan should be included in the complex denominated "Bovine Parasitic Sadness", which currently encompasses only Anaplasma and Babesia.
RESUMO
The present study attempted to verify the prevalence of and risk factors for diarrhea-causing agents in dairy calves from Brazil. Additionally, ages with a higher risk of occurrence for each agent were verified by means of the receiver operating characteristic (ROC) curve. The collections were performed on 39 farms, belonging to 29 municipalities located in eight states of Brazil. It was possible to conclude that the prevalence of Coronavirus, Rotavirus, Cryptosporidium spp., Eimeria spp., and nematodes was 7.20% (95% CI 4.54-9.78), 6.37% (95% CI 3.85-8.89), 51.52% (95% CI 45.26-55.57), 3.46% (95% CI 2.24-4.67), and 3.46% (95% CI 2.24-4.67), respectively. Ages with higher probabilities of occurrence of these diseases in calves were < 10, > 8, > 6, > 37, and > 36 days, respectively. Diarrhea occurred more significantly (P < 0.0001) in animals less than 21 days old and mainly on those receiving milk through automatic feeders (P < 0.001). Cryptosporidium spp. were a risk factor for the occurrence of Rotavirus, and vice versa (P = 0.0039) and presented a positive correlation with Coronavirus (P = 0.0089). Calves that drink water from rivers, streams, and ponds had a higher chance of being infected by Eimeria spp. (P < 0.0001), as well as developing infection by nematodes (P < 0.0001). The results found in this study highlight the importance of studying the agents of diarrhea together, once they act as coinfection where the losses triggered for the owners will involve some of these agents simultaneously.
Assuntos
Doenças dos Bovinos/epidemiologia , Infecções por Coronavirus/veterinária , Criptosporidiose/complicações , Diarreia/veterinária , Infecções por Nematoides/veterinária , Infecções por Rotavirus/veterinária , Animais , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/virologia , Coronavirus/isolamento & purificação , Criptosporidiose/epidemiologia , Cryptosporidium/isolamento & purificação , Diarreia/parasitologia , Diarreia/virologia , Eimeria/isolamento & purificação , Fazendas , Fezes/parasitologia , Fezes/virologia , Feminino , Infecções por Nematoides/complicações , Prevalência , Curva ROC , Fatores de Risco , Rotavirus/isolamento & purificaçãoRESUMO
Eimeria spp. infections cause mortality, reduced well-being, and substantial economic losses implications for cattle production worldwide. The present work followed up the excretion of Eimeria spp. oocysts in two naturally infected beef herds, from two different properties, to investigate the dynamics of oocyst excretion and the prevalence of Eimeria spp. in different animal categories and seasons of the year (rainy season - October to April; dry season - May to September). Even that, the species of Eimeria were identified and the parasitological techniques of Gordon and Whitlock modified and Mini-FLOTAC were used. In both herds, animals up to 14 months had a mean total OPG counts higher than older animals (after 15-16 months of age), and the species E. zuernii and E. bovis were more frequently identified, the first species being more frequent in animals from 1 to 2 months of age, while E. bovis prevailed from three months old. On property 1, the highest mean OPG counts (P ≤ 0.05) were obtained between October 2017 and September 2018, with the highest mean OPG counts in October 2017, when the animals were aged between 4-5 months. The prevalence of the pathogen on property 1 was 59.16 % and 43.62 % in the rainy and dry season, respectively, a higher parasitic load (P ≤ 0.05) was verified in the rainy season. On property 2, the mean OPG counts of Eimeria spp. was higher (P ≤ 0.05) in animals between 8-16 months, with the highest peak in November 2019, when they were one year old. The on-site prevalence during the rainy season on property 2 was 53.09 % and 49.79 % on dry season, and no difference (P = 0.92) in the mean OPG counts of Eimeria spp. during the seasons. There was a difference (P ≤ 0.05) in the count of oocysts in females after 18 months of age than males, which was probably due to the increase in animal density. Both tested techniques can be used for quantification of the excretion of oocysts of Eimeria spp. in cattle feces showing the same OPG mean count (r = 0.9287; p = 0.0025; R² = 0.8625). Mini-FLOTAC showed higher prevalence for Eimeria spp., however, can be an obstacle depending on the number of fecal samples that need to be processed.
Assuntos
Doenças dos Bovinos , Coccidiose , Eimeria/isolamento & purificação , Animais , Bovinos/parasitologia , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Coccidiose/epidemiologia , Coccidiose/veterinária , Fezes/parasitologia , Feminino , Masculino , Oocistos/isolamento & purificação , Contagem de Ovos de Parasitas/veterinária , PrevalênciaRESUMO
The development of a strategic protocol is fundamental to the control of Rhipicephalus microplus. The efficacy of different strategic tick control protocols (Day 1 to Day 119) using commercial acaricides according to R. microplus burden on bovines was evaluated. Female ticks (4.5-8 mm in length) were initially counted on cattle to form four groups of bovines with low and high tick burdens (treated and control), with 10 animals each. The animals were then (Day 0) kept in different paddocks, and the bovines from the two treated groups received their first treatment. The main difference in the protocols was the use of a spray formulation on animals with high tick burden. Additionally, the criterion for animal re-treatment (treatment interval) during the proposed strategic protocol was evaluated according to tick length by visual inspection - if 30% of the bovines of a group presented ticks < 4 mm between their legs and dewlap, the treatment was applied, which could change the originally proposed intervals. The number of days for which animals from the treated groups remained without acaricide administration (palliative control, ≥30 tick females < 4 mm) after the end of the strategic tick control protocol was recorded. Tick counts and visual inspection were done weekly until days 203 and 119, respectively. The results showed that the adopted protocol was successful based on calculated efficacy. Mean efficacies from Day 7 to Day 119 were 86.1% and 96.1% for treated groups with low and high tick burdens, respectively, and mean tick count did not differ between them (P > 0.05) but did differ from their respectively controls (P = <0.0001). The use of spray formulation at the beginning of the protocol for animals with a high tick burden helped to avoid harmful tick infestations. Visual analysis of tick length anticipated the proposed treatment intervals. Treated groups remained without palliative treatment for 70 days, while control groups needed treatment every 28 days. It was concluded that strategic control protocols must be developed according to tick burden, and tick length can be used to indicate when treatment needs to be applied.
Assuntos
Acaricidas , Doenças dos Bovinos/prevenção & controle , Rhipicephalus , Controle de Ácaros e Carrapatos , Infestações por Carrapato/veterinária , Animais , Brasil , Bovinos , Doenças dos Bovinos/parasitologia , Feminino , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/parasitologia , Infestações por Carrapato/prevenção & controleRESUMO
The present study evaluated over two years the seasonal dynamics of Rhipicephalus microplus in a Cerrado biome of midwestern Brazil (Goiânia, Goiás) and correlated the current climatic conditions (environmental temperature, insolation, rainfall, relative humitidy and saturation deficit of the atmosphere) of this site with 30 years ago. In addition, the data collected in the present research were compared with climatic conditions data and R. microplus population dynamics conducted by our group in other regions (Formiga, Minas Gerais and Jaboticabal, São Paulo) within the same biome. For the parasitic phase dynamics, R. microplus females (4.5-8.0â¯mm) counts were performed on tick natural infested cows kept in Panicum maximum paddocks. To verify the larvae dynamics on pasture the flannel dragg technique on natural infested pasture was performed, and the height of the grass was measured. Five peaks of engorged R. microplus females on animals and larvae infestations on pastures were observed. Being three and two peaks during the rainy and dry season of the year, respectively. Insolation (râ¯=â¯0.8758; Pâ¯=â¯0.00009; R²â¯=â¯0.7670), rainfall (r = -0.8572; Pâ¯=â¯0.0002; R²â¯=â¯0.7348), maximum environmental temperature in summer (râ¯=â¯0.9999; Pâ¯<â¯0.0087; R²â¯=â¯0.9988) and the saturation deficit of the atmosphere in autumn (r = -0.9789; Pâ¯=â¯0.0211; R²â¯=â¯0.9582) influenced the seasonal dynamics of R. microplus larvae on pastures. While the forage height did not influence the number of larvae found on pasture (râ¯=â¯0.1545; Pâ¯=â¯0.7682; R²â¯=â¯0.0239). The comparison between the climatic data of the last 30 years with the current climatological data (2012 to 2019) in the state of Goiás, and the comparison with R. microplus population dynamics from other two locations in the same biome indicated that the increase of the environmental temperature due to the global warming possibly is a determining factor which increase the number of one or up two tick annual peaks. In addition, this climatic variable was responsible for increase the population density of ticks on pastures and animals observed in July/winter of the present study, in comparison to other regions with the same biome, as discussed in this work.
Assuntos
Doenças dos Bovinos , Aquecimento Global , Rhipicephalus , Estações do Ano , Infestações por Carrapato , Animais , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Ecossistema , Feminino , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterináriaRESUMO
Trypanosoma vivax causes bovine trypanosomosis in cattle and resulting in economic losses to farmers. In Brazil, shared contaminated materials is the main transmission pathway. To evaluate the effectiveness of different disinfectants for T. vivax, in vitro and in vivo analyses were performed. At the laboratory, 21 disinfectants were tested. The disinfectants were placed in microtubes containing blood with approximately 1.0 × 106 trypomastigotes of T. vivax. The viability and motile of trypomastigotes after 30 s, one, 10, 15 and 30 min was evaluated by the thick drop method and the efficacy calculated. Disinfectants that showed 100% effectiveness were used in in vivo tests. Thirty calves negative for T. vivax were divided into six groups and were inoculated with disinfectant solutions (46% alcohol, 70% alcohol, or 0.5% iodine) + 1 × 106 trypomastigotes of the protozoa. Blood from each animal was collected at seven, 14 and 21 days after inoculation to verify the viability and presence of the protozoan by Woo, Brener, PCR, and LAMP methods. In the in vitro step, 13 of the 21 disinfected solutions exhibited 100% effectiveness against T. vivax at all evaluation times. In contrast, 70% alcohol and 0.5% iodine solutions exhibited 100% effectiveness in the in vivo tests and can be used to disinfect needles and syringes. The use of disinfectants is a rapid and efficient procedure to disinfect materials utilized in the field and concomitantly could help to reduce the dissemination of T. vivax in the cattle herd in cases of iatrogenic transmission.
Assuntos
Doenças dos Bovinos , Desinfetantes , Tripanossomíase Bovina , Animais , Brasil , Bovinos , Doenças dos Bovinos/prevenção & controle , Desinfetantes/farmacologia , Reação em Cadeia da Polimerase/veterinária , Trypanosoma vivax , Tripanossomíase Bovina/parasitologiaRESUMO
The objective of this study was to evaluate two different gastrointestinal nematode treatment regimens. Fecal egg counts (FECs), proportion of nematode genera, weight gain, body condition score and reproductive indices (estrous cyclicity, conception and pregnancy rates) were evaluated in yearling heifers after imposing two treatment regimens for gastrointestinal nematodes: T1â¯=â¯306 calves treated in May and November with 3.5 % doramectin (700⯵g/kg) and August (Aug) with saline solution; and T2â¯=â¯307 calves treated in May with 3.5 % doramectin (700⯵g/kg), in August with 1% moxidectin (200⯵g/kg) and in November with 3.5 % doramectin (700⯵g/kg). The animals were weighed, and feces were collected for conducting FECs and coproculture. There was imposing of three fixed-time artificial inseminations (TAIs), and estrous cyclic and pregnancy statuses were determined. Cooperia was the most frequent genus detected in both groups. Heifers of the T2, as compared to those in the T1 group, had fewer FECs in November (Pâ¯≤⯠0.05) and greater weight gain and average daily weight gain (Pâ¯≤⯠0.05) from August to November. There tended to be more heifers of the T2 than T1 group estrous cycling (Pâ¯=⯠0.07) at the beginning of the breeding season as well as greater pregnancy rates (Pâ¯=⯠0.03) and conception rates (Pâ¯=⯠0.03) as a result of the second FTAI. The results indicate there is greater reproduction outcomes as a result of strategic control of gastrointestinal nematodes in yearling Nellore heifers using the T1 as compared with T2 treatment regimen.
Assuntos
Doenças dos Bovinos , Fezes , Ivermectina , Macrolídeos , Infecções por Nematoides , Contagem de Ovos de Parasitas , Animais , Bovinos , Feminino , Gravidez , Anti-Helmínticos/administração & dosagem , Anti-Helmínticos/uso terapêutico , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/parasitologia , Ciclo Estral/fisiologia , Fezes/parasitologia , Ivermectina/administração & dosagem , Ivermectina/análogos & derivados , Ivermectina/uso terapêutico , Macrolídeos/administração & dosagem , Macrolídeos/uso terapêutico , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/veterinária , Aumento de PesoRESUMO
Rhipicephalus microplus is the most significant tick of livestock and its control is particularly challenging due to its resistance to commercial acaricides. Pasture rotation is considered a management strategy that could help control R. microplus, however, the literature only contemplates mathematical models and little is known about the effects of this practice in the field. The objective of this work was to determine whether pasture rotation is an efficient method for controlling R. microplus. Two different experiments were performed that involved groups of continuous and rotational grazing bovines. Female ticks measuring 4.5-8.0 mm were counted on animals while larvae in pasture were counted using the flannel drag technique. Treatment for infested bovines was applied when the average group tick count was ≥30 females. The results showed that rotational grazing (with 20-day periods of rest) had a higher tick count on-host than continuous grazing (P < 0.05) and additional bovine treatment was needed. Sixty and 105 days were needed to re-infest and disinfest pasture of R. microplus larvae, respectively. The first treatment of bovines occurred 91 days after the animals were placed in a closed area. The results indicate that rotational grazing is not an efficient way to control R. microplus.
Assuntos
Criação de Animais Domésticos , Doenças dos Bovinos/prevenção & controle , Rhipicephalus/fisiologia , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/veterinária , Acaricidas/farmacologia , Criação de Animais Domésticos/métodos , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Feminino , Larva/efeitos dos fármacos , Infestações por Carrapato/prevenção & controleRESUMO
Rhipicephalus (Boophilus) microplus is the most important livestock tick, causing economical losses especially in tropical and subtropical regions. Pour-on formulations using synthetic chemicals, remain the most farmer friendly conventional form of tick control method. Misuse of acaricides can lead to the emergence of resistance, residual chemicals in animal products, the poisoning of vertebrates and environment contamination. Despite the increase in the use of pour-on formulations, little is known regarding the therapeutic and residual efficacy of these products after the treated animals are exposed to rainfall. Moreover, information is scanty on whether efficacy is modulated by different levels of tick burden. Three studies were conducted. In the two first experiments, we evaluated the therapeutic and residual efficacies of commercial pour-on products (fluazuron 2.5 mg/kg and fipronil 1.0 mg/kg, respectively) on cattle naturally infested with R. (B.) microplus under the condition of simulated rainfall. In the third study, we investigated whether tick burden affects the efficacy of the drugs used a chemical control method involving three different formulations (Day 0: cypermethrin 5.0 mg/kg + chlorpyrifos 7.0 mg/kg + citronellal 0.5 mg/kg; Day 7: fluazuron 3.0 mg/kg + abamectin 0.5 mg/kg and Day 56: fipronil 1.0 mg/kg + fluazuron 3.0 mg/kg). Tick counts were performed on different days to assess efficacy. It was observed that the residual efficacy of the commercial formulations was lower on animals that received simulated rain. In addition, therapeutic and residual efficacies of the products were reduced in the group of animals with a high tick burden of R. (B.) microplus. In conclusion, rainfall decreases the efficacy of acaricides. Also, the tick burden must be considered when selecting a pour-on formulation.
Assuntos
Acaricidas/uso terapêutico , Doenças dos Bovinos/prevenção & controle , Rhipicephalus , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/veterinária , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Densidade Demográfica , Chuva , Infestações por Carrapato/parasitologia , Infestações por Carrapato/prevenção & controleRESUMO
In this study, we evaluated the therapeutic efficacy of diminazene diaceturate at a dose of 7 mg/kg (DA), imidocarb dipropionate at 4.8 mg/kg (IMD), isometamidium chloride at 0.5 and 1.0 mg/kg (ISM 0.5 and ISM 1.0) and combinations applied through different methods to treat Trypanosoma vivax in experimentally infected calves. Thirty male Girolando calves were kept indoors and infected intravenously with T. vivax trypomastigotes (approximately 1 × 106). On D-1, the calves were randomized based on the quantity of infecting parasites per animal, yielding six groups of five animals each: G1: positive control group without treatment; G2 animals treated with DA on Day 0 intramuscularly (IM); G3 animals treated with IMD on Day 0 and D + 14 subcutaneously; G4 animals treated with ISM 0.5 on Day 0 IM; G5 animals treated with ISM 1.0 on Day 0 IM; G6 animals received DA on Day 0 and ISM 1.0 on D + 14, both IM. Throughout 180 days, blood samples were collected for the evaluation of T. vivax using the Woo, Brener and PCR methods. The results indicated that the treatment protocols with DA and/or ISM 0.5 and ISM 1.0 had high efficacy (100 %) against T. vivax. Interestingly, cattle that received ISM remained free of parasites until D + 180. In contrast, animals treated with IMD had relapsed T. vivax detected on the 10th and 14th days post-treatment (DPT). Cattle that received ISM 1.0 did not exhibit relapsed T. vivax in the blood, even after reinfection performed on the 50th DPT. However, treatment with DA on Day 0 failed to prevent a new infection of T. vivax on the 50th DPT. The animals that received ISM 1.0 had a transient decrease in packed cell volume similar to that found in the control group. The reappearance of T. vivax in herds in Brazil treated with DA likely occurred due to the short half-life of the drug and not necessarily due to T. vivax resistance to DA.
Assuntos
Diminazena/análogos & derivados , Imidocarbo/análogos & derivados , Fenantridinas/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma vivax/efeitos dos fármacos , Tripanossomíase Africana/prevenção & controle , Tripanossomíase Bovina/prevenção & controle , Animais , Bovinos , Diminazena/farmacologia , Relação Dose-Resposta a Droga , Imidocarbo/farmacologia , MasculinoRESUMO
This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females.
Assuntos
Doenças dos Bovinos/tratamento farmacológico , Diflubenzuron/administração & dosagem , Ectoparasitoses/veterinária , Muscidae/efeitos dos fármacos , Rhipicephalus/efeitos dos fármacos , Infestações por Carrapato/veterinária , Animais , Bovinos , Suplementos Nutricionais , Ectoparasitoses/tratamento farmacológico , Feminino , Infestações por Carrapato/tratamento farmacológico , Resultado do TratamentoRESUMO
This study aimed to identify the frequency of occurrence of Eimeria species in Holstein (taurine dairy cattle) and Nelore (zebu beef cattle) on 12 farms in the state of Goiás, Brazil. A total of 2,601 animals were evaluated, and the cattle were divided into the following age-group categories: up to three months old, four to eight months old, nine to 16 months old and cows. Fecal samples were collected directly from the rectum of all animals. None of the cattle presented any clinical signs of eimeriosis during the survey. From the results obtained, it could be concluded that higher rates of infection by Eimeria spp. were observed in Holstein cattle between the 1st and 16 th months of age and in Nelore cattle between the 1st and 8th months of age. Twelve and nine Eimeria species were diagnosed in Holstein and Nelore cattle, respectively. However, Eimeria zuernii was more prevalent in animals up to three months old, while Eimeria bovis was more common in the remaining categories (cattle aged four months and over). Future studies on the epidemiology and/or seasonality of infection by Eimeria species in cattle, from birth onwards, are needed in order to better understand the dynamics of E. zuernii and E. bovis occurrences, especially in cattle under three months of age.
Assuntos
Doenças dos Bovinos/parasitologia , Bovinos/parasitologia , Coccidiose/veterinária , Eimeria/isolamento & purificação , Fatores Etários , Animais , Brasil/epidemiologia , Doenças dos Bovinos/epidemiologia , Coccidiose/epidemiologia , Indústria de Laticínios , Carne VermelhaRESUMO
The present study had to determine the prevalence and spatial distribution of areas at risk of bovine fascioliasis in the state of Goiás, central-western Brazil between 2007 and 2014; to evaluate the associations of some epidemiological variables with occurrences of Fasciola hepatica in animals; and to estimate the economic losses that this parasite on the cattle industry. It could be concluded that of 23,255,979 animals slaughtered, the average prevalence of F. hepatica in cattle in Goiás during the period evaluated was 0.0026% (95% CI: 0.0024-0.0028). In the State of Goias, in about then years (since when this parasite was found for the first time by other researchers in 2007), F. hepatica was diagnosed in 168 new municipalities. Using the regression analysis, the effective bovine herd size was a significant risk factor (OR= 1.21; 95% CI 1.1022-1.4510; p ≤ 0.05) for cattle to be infected with fascioliasis in the state of Goiás. The cattle-rearing industry lost approximately R$ 15,072.75 (US$ 4,785) due to condemn of livers with Fasciola in the state of Goiás. New studies need to be conducted in these regions, with the aim to identify the likelihood of presence of intermediate hosts, which might serve as a source of F. hepatica infection for definitive hosts.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Fasciolíase/veterinária , Animais , Brasil/epidemiologia , Bovinos , Fasciolíase/epidemiologia , Prevalência , Estudos RetrospectivosRESUMO
Trypanosomiasis caused by Trypanosoma vivax has increased the reports in Brazil in the last decade. An outbreak is herein first reported in the state of Goiás, from May 2016 to January 2017. The outbreak start occurred in the city of Ipameri (Goiás) after the introduction of 18 auctioned cows from the state of Minas Gerais. Direct parasitological test (blood smears) and polymerase chain reactions targeting the catL genes diagnosed T. vivax infection. Fifty six cows from a herd of 161 were infected; 12 died during the outbreak and 44 animals persistently positive (by blood smears) even after chemical treatment were discarded. After this first case, five other cases were detected in state of Goiás. The spread of this disease can be linked to the commercialization of animals carrying T. vivax, allied to the iatrogenic transmission practice, using a single needle and syringe for all cows, during oxytocin administration before each milking.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Surtos de Doenças , Trypanosoma vivax , Tripanossomíase Bovina/epidemiologia , Animais , Brasil/epidemiologia , Bovinos , Indústria de Laticínios , Feminino , Tripanossomíase/epidemiologia , Tripanossomíase/veterináriaRESUMO
Abstract This study aimed to identify the frequency of occurrence of Eimeria species in Holstein (taurine dairy cattle) and Nelore (zebu beef cattle) on 12 farms in the state of Goiás, Brazil. A total of 2,601 animals were evaluated, and the cattle were divided into the following age-group categories: up to three months old, four to eight months old, nine to 16 months old and cows. Fecal samples were collected directly from the rectum of all animals. None of the cattle presented any clinical signs of eimeriosis during the survey. From the results obtained, it could be concluded that higher rates of infection by Eimeria spp. were observed in Holstein cattle between the 1st and 16 th months of age and in Nelore cattle between the 1st and 8th months of age. Twelve and nine Eimeria species were diagnosed in Holstein and Nelore cattle, respectively. However, Eimeria zuernii was more prevalent in animals up to three months old, while Eimeria bovis was more common in the remaining categories (cattle aged four months and over). Future studies on the epidemiology and/or seasonality of infection by Eimeria species in cattle, from birth onwards, are needed in order to better understand the dynamics of E. zuernii and E. bovis occurrences, especially in cattle under three months of age.
Resumo O presente trabalho teve como objetivo identificar a frequência das espécies de Eimeria spp. em bovinos holandeses (bovinos de leite) e Nelore (bovinos de corte) em 12 propriedades no Estado de Goiás. Foi avaliado um total de 2.601 animais, e em cada propriedade, os bovinos foram divididos nas seguintes categorias conforme a idade: até 3 meses, 4 a 8 meses, 9 a 16 meses e vacas. Amostras de fezes foram coletadas diretamente da ampola retal dos animais. Com base nos resultados obtidos pode-se concluir que em holandeses e Nelores, o maior número de bovinos infectados por Eimeria spp. foi observado do 1º ao 16º e do 1º ao 8º meses de idade, respectivamente. Não houve nenhum caso de eimeriose clínica durante a pesquisa. Doze e nove espécies de Eimeria foram diagnosticadas em holandeses e Nelores, respectivamente. As duas espécies mais frequentes foram Eimeria bovis e Eimeria zuernii, entretanto, E. zuernii foi mais prevalente em animais até os 3 meses de idade, enquanto que E. bovis foi a mais frequente nas demais categorias de bovinos, a partir dos 4 meses de idade. Futuros estudos relacionados à epidemiologia e/ou de sazonalidade da infecção por espécies Eimeria spp., em bovinos desde o seu nascimento, são necessários, a fim de melhor entender a dinâmica de ocorrência de E. zuernii e E. bovis principalmente em bezerros com até 3 meses de idade.