First record of a possible trypanotolerant cattle breed in Latin America: Parasitological, serological, and clinical aspects.

Trypanosoma vivax infections are endemic in Africa, where they provoke trypanosomosis against which some local taurine breeds are tolerant and are thus named trypanotolerant. In Latin America, T. vivax was imported in 1919, since when it has been responsible for periodic outbreaks of the disease. This study assessed whether a South American taurine breed resilient to several parasitic and infectious diseases (Curraleiro Pé-Duro-CPD) can meet trypanotolerant criteria (control parasite proliferation, prevent anemia, survive without treatment, and maintain productivity). Three groups were established, each consisting of six animals (Group 1: CPD-infected; Group 2: Holstein/Gyr-infected; Group 3: Holstein/Gyr-uninfected, negative control). Groups 1 and 2 were infected with T. vivax on Day 0 and evaluated until day 532. Throughout the experimental period, parasitological (Woo and Brener), molecular (cPCR), serological (enzyme-linked immunosorbent assay - ELISA, indirect fluorescent antibody test - IFAT, immunochromatographic assay - IA), and clinical (hemogram, fever, weight loss) aspects were evaluated. During the acute phase of the disease, T. vivax was initially detected in Holstein/Gyr. Notably, the CPD animals restored their packed cell volume (PCV) values to the normal range 74 days after inoculations. In the chronic phase, two of the six CPD animals were positive by cPCR until D + 522 following immunosuppression with dexamethasone. Regarding serological aspects, the two CPD animals had positive tests until D + 532. The absence of T. vivax in blood during the chronic phase did not correspond to "self-cure". Holstein/Gyr animals exhibited fever on more evaluation days than CPD animals. Both breeds experienced weight loss, with Holstein/Gyr animals losing significantly more weight. On D + 25, the Holstein/Gyr group required treatment. During the 532 days, none of the CPD animals required treatment, even after being sensitized with dexamethasone. Animals from Group 3 tested negative for T. vivax throughout the experiment. This study demonstrated that CPD cattle fulfill the mentioned trypanotolerant criteria.

Seroprevalence of trypanosomosis and associated risk factors in cattle from coast and amazonian provinces of Ecuador.

Trypanosomosis is a tropical disease caused by various protozoan haemoparasites, which affects wild and domestic animals, the latter ones related to worldwide livestock production systems. Species such as Trypanosoma vivax and Trypanosoma evansi have been described using serological and molecular tools in several countries from South and Central America. However, Ecuador presents a relevant knowledge gap in the associated general epidemiology and risk factors of the disease. Therefore, the objective of this study was to determine the seroprevalence of trypanosomosis in cattle from different regions of Ecuador. 745 serum samples from 7 Coastal and 3 Amazon provinces were screened for IgG anti-Trypanosoma spp. antibodies, using an in-house indirect ELISA. The seropositivity was explored and associated with several variables such as sex, age, breed, region, management, and province, using statistical tools. The general seroprevalence of trypanosomosis was 19.1% (95% CI: 16.30-22.1%). The Amazonian provinces of Sucumbíos and Napo and the Coastal province of Esmeraldas presented the highest seroprevalence values of 36.7% (95% CI: 27.67-46.47%), 23.64% (95% CI: 16.06-32.68%) and 25% (95% CI: 15.99-35.94%), respectively. Statistical significance was found for the region, province, and management variables, indicating as relevant risk factors the extensive management and Amazon location of the cattle analyzed. Specific actions should be taken to identify the exact species on reservoirs and susceptible hosts, evaluate the implication of farm management and cattle movement as risk factors, and implement surveillance and treatment plans for affected herds.

Detection of anti-Trypanosoma spp. antibodies in cattle from southern Brazil.

Bovine trypanosomosis, caused by Trypanosoma vivax, is a disease that originated in Africa and currently affects cattle in several South American countries, including almost all Brazilian states. Despite the reports on T. vivax infection in southern Brazil, data on its circulation status is currently unavailable. In this study, we aimed to detect anti-Trypanosoma spp. IgG antibodies in cattle from Rio Grande do Sul and suggest areas with T. vivax transmission risk. A total of 691 serum samples from cattle in the intermediate regions of Rio Grande do Sul were analyzed using indirect immunofluorescence assay (IFA). The overall seroprevalence of anti-Trypanosoma antibodies in cattle was 24.6% (170/691). The detection rate ranged from 0-37.3%, with a high prevalence in the intermediate regions of Ijuí (37.3%), Uruguaiana (30.7%), and Passo Fundo (28.9%). Thus, these regions were suggested as possible bovine trypanosomosis risk areas due to the high seroprevalence. This is the first serological study to determine Trypanosoma spp. infection status in cattle from Rio Grande do Sul, providing data on the epidemiology of trypanosomosis in the state.

Methods Applied to the Diagnosis of Cattle Trypanosoma vivax Infection: An Overview of the Current State of the Art.

Bovine trypanosomiasis caused by Trypanosoma vivax is a relevant disease in domestic ungulates in Latin America, causing different types of livestock losses, particularly in African and South American countries, leading to loss of millions of dollars/year related to dairy and meat production. In addition, T. vivax trypanosomiasis requires intensive veterinary care. While vector control is a feasible measure to manage disease spreading, the search for accurate diagnostic tools still represents a gap in routine veterinary practices and a challenge for the scientific community. The parasite is mechanically transmitted by fomites or by the saliva of haematophagous flies, such as Stomoxys sp. and Tabanus sp., infecting cattle as well as a number of animal hosts. The main symptoms of T. vivax bovine trypanosomiasis are apathy, fever, restricted growth, miscarriage, progressive weakness, neurological signs, pale mucous, loss of appetite, lethargy, and substantial weight loss. In most cases, the presence of animals with subclinical infections, nonspecific symptoms and without apparent parasitaemia presents a challenge when making a diagnosis, which requires accurate methods. Herein, we review state of the art concerning current methods available for the diagnosis of T. vivax bovine trypanosomiasis, focusing on clinical, parasitological, immunological and molecular approaches, highlighting the main features of each method, including "pros and cons". Overall, combining several diagnostic techniques is a better choice since it leads to fewer false negative results and contributes to better disease control.

First detection of Trypanosoma vivax in dairy cattle from the northwest region of Minas Gerais, Brazil / Primeira detecção de Trypanosoma vivax em bovinos leiteiros da região noroeste de Minas Gerais, Brasil

A tripanossomíase bovina é causada pelo protozoário Trypanosoma vivax. A transmissão biológica ocorre apenas no continente africano pela mosca Tsé-tsé, de forma mecânica por dípteros hematófagos em todos os continentes, ou pelo compartilhamento de agulhas e por práticas associadas. O estudo teve como objetivo relatar o primeiro diagnóstico parasitológico, sorológico e molecular de T. vivax em bovinos leiteiros provenientes de cinco propriedades do município de Unai, Minas Gerais, Brasil. Cento e quinze animais selecionados por conveniência apresentavam sinais clínicos ou pertenciam a lotes de animais suspeitos. Foram detectados positivos pelos testes parasitológico (técnica de Woo), sorológico (ELISA) e molecular (LAMP). A maior prevalência global para T. vivax foi de 11,11% na propriedade A. O único sinal clínico dos animais positivos estudados foi baixa taxa de concepção. O primeiro diagnóstico de tripanossomíase no noroeste mineiro é extremamente importante, haja vista o tamanho do rebanho leiteiro da região e as possíveis perdas econômicas provocadas pela enfermidade. Ademais, faz-se necessário maior controle sanitário na região, uma vez que a transmissão no Brasil é intimamente ligada às práticas de compartilhamento de agulhas no manejo dos animais e ao parasitismo de moscas hematófagas.

A cerumenolomic approach to bovine trypanosomosis diagnosis.

INTRODUCTION: Trypanosomiasis caused by Trypanosoma vivax (T. vivax, subgenus Duttonella) is a burden disease in bovines that induces losses of billions of dollars in livestock activity worldwide. To control the disease, the first step is identifying the infected animals at early stages. However, convention tools for animal infection detection by T. vivax present some challenges, facilitating the spread of the pathogenesis. OBJECTIVES: This work aims to develop a new procedure to identify infected bovines by T. vivax using cerumen (earwax) in a volatilomic approach, here named cerumenolomic, which is performed in an easy, quick, accurate, and non-invasive manner. METHODS: Seventy-eight earwax samples from Brazilian Curraleiro Pé-Duro calves were collected in a longitudinal study protocol during health and inoculated stages. The samples were analyzed using Headspace/Gas Chromatography-Mass Spectrometry followed by multivariate analysis approaches. RESULTS: The cerumen analyses lead to the identification of a broad spectrum of volatile organic metabolites (VOMs), of which 20 VOMs can discriminate between healthy and infected calves (AUC = 0.991, sensitivity = 0.967, specificity = 1.000). Furthermore, 13 VOMs can indicate a pattern of discrimination between the acute and chronic phases of the T. vivax infection in the animals (AUC = 0.989, sensitivity = 0.944, specificity = 1.000). CONCLUSION: The cerumen volatile metabolites present alterations in their occurrence during the T.vivax infection, which may lead to identifying the infection in the first weeks of inoculation and discriminating between the acute and chronic phases of the illness. These results may be a breakthrough to avoid the T. vivax outbreak and provide a faster clinical approach to the animal.

How many cattle can be infected by Trypanosoma vivax by reusing the same needle and syringe, and what is the viability time of this protozoan in injectable veterinary products?

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.

Evaluation of techniques for diagnosis of Trypanosoma vivax infections in naturally infected cattle in the Zona da Mata Mineira.

This study aimed to evaluate diagnostic techniques for trypanosomiasis, caused by Trypanosoma vivax, in naturally infected cattle in Minas Gerais, Zona da Mata. The deaths of six lactating cows with similar clinical conditions-characterized by hyporexia, hypogalactia, and recumbency-had been reported from one property. Initially, two animals were examined and diagnosed with trypanosomiasis through identification of the protozoan in a blood smear. After the initial diagnosis, all lactating cows (n=37) on the property were examined, and blood samples were collected for tests including whole blood smear, buffy coat smear, Woo's technique, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR). Woo's test, buffy coat smears, and whole blood smears indicated that 4/37 (10.81%) animals were positive for trypanosomiasis, whereas ELISA and PCR indicated that 33/37 (89.19%) and 27/37 (72.97%) animals, respectively, were positive. The agreement obtained between parasitological techniques was classified as high, while between ELISA and PCR, no agreement. In conclusion, parasitological techniques have a low capacity to identify infected animals in the chronic stage of T. vivax infection. Therefore, techniques such as PCR and/or ELISA should be used to minimize the occurrence of false negatives.

Serum prevalence of anti-Trypanosoma vivax antibodies in cattle in Tapira-MG, Brazil / Soroprevalência de anticorpos anti-Trypanosoma vivaxem bovinos em Tapira-MG, Brasil

Trypanosoma vivax is considered the most important pathogenic Trypanosoma for cattle and causes great damage to the dairy and beef cattle industries. This study aimed to evaluate the prevalence of anti-T. vivax antibodies in dairy cattle from the municipality of Tapira, located in the Alto Paranaíba region, Minas Gerais, Brazil. The 74 blood serum samples from dairy cattle were analyzed using an indirect immunofluorescence reaction. The seroprevalence was 82.4 % (61/74), and the highest incidence observed can be correlated with the transit of untested animals, the presence of vectors, and needle sharing by owners. The data allowed defining Tapira as an area of expansion of T. vivax epizootic infections in the state of Minas Gerais.

O Trypanosoma vivax é considerado o mais importante trypanosoma patogênico para bovinos e causa grandes prejuízos na pecuária de corte e leite. Este estudo teve como objetivo avaliar a prevalência anticorpos de anti-Trypanosoma vivax em bovinos leiteiros do município de Tapira, localizado na região do Alto Paranaíba, Minas Gerais, Brasil. As 74 amostras de soro sanguíneo de bovinos leiteiros foram analisadas por meio de reação de imunofluorescência indireta. A soroprevalência foi de 82,4% (61/74), que pode estar relacionada ao trânsito de animais não testados, presença de vetores e compartilhamento de agulhas pelos proprietários. Os dados permitiram definir Tapira como uma área de expansão das infecções epizoóticas por Trypanosoma vivax no estado de Minas Gerais.

Tripanosomíase no rebanho bovino brasileiro ­ Uma breve revisão da literatura / Trypanosomiasis in cattle - Brief literature review / Tripanosomiasis en el ganado - Breve revisión de la literatura

Ao possuir um dos maiores rebanhos comerciais de bovinos do mundo, o Brasil destaca-se entre os demais países, entretanto, dentre os problemas sanitários que acometem esses rebanhos a tripanossomose vem ganhando espaço e grande significância, devido aos grandes problemas econômicos e reprodutivos que vem causando no rebanho brasileiro. O agente de maior importância e causador é o Trypanossoma vivax, que são protozoários disseminados por meio de vetores mecânicos, como tabanídeos e moscas hematófagas como as do gênero Stomoxys. Esses agentes estão distribuídos por todo o mundo, mas preferencialmente em áreas de clima tropicais no Brasil, acometendo tanto bovinos leiteiros quanto bovinos de corte, causando grandes prejuízos aos criadores. Os sinais clínicos desta doença são inespecíficos, o que tem gerado preocupação pela disseminação e falta de diagnóstico dessa enfermidade, mas incluem, principalmente, anemia ou perda progressiva de peso, além de perda da produtividade dos animais acometidos. O diagnóstico é feito por meio de exames parasitológicos, como esfregaços sanguíneos, exames sorológicos e molecular e, principalmente, pelo método de Woo. Por fim o tratamento e controle dessa doença consiste em tratamentos quimioterápicos e controle dos vetores causadores. Neste sentido, esta breve revisão de literatura tem por objetivo levantar dados sobre tal doença, como: agente etiológico, sinais clínicos, epidemiologia, diagnóstico e tratamento, a fim de contribuir com informações sobre a enfermidade que está ganhando espaço e necessita de maior disseminação de conhecimentos, para que não seja esquecida e subdiagnosticada.(AU)

Having one of the largest commercial herds of cattle in the world, Brazil stands out among other countries, however, among the sanitary problems that affect these herds, Trypanosomosis has been gaining space and great significance, due to the major economic and reproductive problems that are coming causing in the brazilian herd. The most important and causative agent is Trypanosoma vivax, which are protozoa disseminated by mechanical vectors, such as horseflies and hematophagous flies such as those of the genus Stomoxys. These agents are distributed all over the world, but preferentially in tropical climate areas in Brazil, affecting both dairy and beef cattle, causing great damage to farmers. The clinical signs of this disease are nonspecific, which has raised concern about the spread and lack of diagnosis of this disease, but mainly include anemia or progressive weight loss, in addition to loss of productivity in affected animals. Diagnosis is made through parasitological tests, such as blood smears, serological and molecular tests, and, mainly, using the Woo method. Finally, the treatment and control of this disease consists of chemotherapy treatments and control of the causative vectors. In this sense, this brief literature review aims to raise data on this disease, such as: etiological agent, clinical signs, epidemiology, diagnosis and treatment, in order to contribute with information about the disease that is gaining ground and needs further dissemination of knowledge, so that it is not forgotten and underdiagnosed.(AU)

Teniendo uno de los rebaños comerciales de ganado más grandes del mundo, Brasil se destaca entre otros países, sin embargo, entre los problemas sanitarios que afectan a estos rebaños, la tripanosomosis ha ido ganando espacio y gran trascendencia, debido a los grandes problemas económicos y reproductivos que son que viene provocando en el rebaño brasileño. El agente causal más importante es Trypanosoma vivax, que son protozoos diseminados a través de vectores mecánicos, como tábanos y moscas hematófagas como las del género Stomoxys. Estos agentes se distribuyen por todo el mundo, pero preferentemente en las zonas de clima tropical de Brasil, afectando tanto al ganado lechero como al vacuno, causando grandes daños a los ganaderos. Los signos clínicos de esta enfermedad son inespecíficos, lo que ha suscitado preocupación por la diseminación y falta de diagnóstico de esta enfermedad, pero principalmente incluyen anemia o pérdida progresiva de peso, además de pérdida de productividad en los animales afectados. El diagnóstico se realiza mediante pruebas parasitológicas, como frotis de sangre, pruebas serológicas y moleculares y, principalmente, mediante el método Woo. Finalmente, el tratamiento y control de esta enfermedad consiste en tratamientos de quimioterapia y control de los vectores causantes. En este sentido, esta breve revisión de la literatura tiene como objetivo levantar datos sobre esta enfermedad, tales como: agente etiológico, signos clínicos, epidemiología, diagnóstico y tratamiento, con el fin de aportar información sobre la enfermedad que está ganando terreno y necesita una mayor difusión del conocimiento. para que no sea olvidado e infradiagnosticado.(AU)

Evaluation of techniques for diagnosis of Trypanosoma vivax infections in naturally infected cattle in the Zona da Mata Mineira / Avaliação de técnicas para diagnóstico de infecções por Trypanosoma vivax em bovinos naturalmente infectados na Zona da Mata Mineira

Abstract This study aimed to evaluate diagnostic techniques for trypanosomiasis, caused by Trypanosoma vivax, in naturally infected cattle in Minas Gerais, Zona da Mata. The deaths of six lactating cows with similar clinical conditions—characterized by hyporexia, hypogalactia, and recumbency—had been reported from one property. Initially, two animals were examined and diagnosed with trypanosomiasis through identification of the protozoan in a blood smear. After the initial diagnosis, all lactating cows (n=37) on the property were examined, and blood samples were collected for tests including whole blood smear, buffy coat smear, Woo's technique, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR). Woo's test, buffy coat smears, and whole blood smears indicated that 4/37 (10.81%) animals were positive for trypanosomiasis, whereas ELISA and PCR indicated that 33/37 (89.19%) and 27/37 (72.97%) animals, respectively, were positive. The agreement obtained between parasitological techniques was classified as high, while between ELISA and PCR, no agreement. In conclusion, parasitological techniques have a low capacity to identify infected animals in the chronic stage of T. vivax infection. Therefore, techniques such as PCR and/or ELISA should be used to minimize the occurrence of false negatives.

Resumo Este estudo objetiva avaliar as técnicas de diagnóstico da tripanossomíase, causada pelo Trypanosoma vivax, em bovinos naturalmente infectados, em Minas Gerais, Zona da Mata. A morte de seis vacas em lactação com condições clínicas semelhantes - caracterizadas por hiporexia, hipogalaxia e decúbito - foi relatada em uma propriedade. Inicialmente, dois animais foram examinados e diagnosticados com tripanossomíase através da identificação do protozoário em esfregaço sanguíneo. Após o diagnóstico inicial, todas as vacas em lactação (n = 37) na propriedade foram examinadas, e amostras de sangue foram coletadas para testes, incluindo esfregaço de sangue total, esfregaço de capa leucocitária, técnica de Woo, ensaio imunoenzimático (ELISA) e reação em cadeia da polimerase (PCR). O teste de Woo, os esfregaços de capa leucocitária e de sangue total indicaram que 4/37 (10,81%) animais foram positivos para tripanossomíase, enquanto ELISA e PCR indicaram que 33/37 (89,19%) e 27/37 (72,97%) animais, respectivamente, foram positivos. A concordância entre técnicas parasitológicas foi classificada como alta, enquanto entre ELISA e PCR, sem concordância. As técnicas parasitológicas apresentam baixa capacidade para identificar animais infectados na fase crônica da infecção por T. vivax. Dessa forma, técnicas como PCR e/ou ELISA devem ser utilizadas para minimizar a ocorrência de falsos negativos.

In vitro and in vivo effectiveness of disinfectants against Trypanosoma vivax.

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.

Evaluation of five primer sets for molecular detection of Trypanosoma vivax by polymerase chain reaction (PCR) and their implementation for diagnosis in naturally infected ruminants from Venezuela.

Trypanosoma vivax is a protozoan parasite that causes trypanosomosis in ruminants and is widely distributed in tropical areas in the world. The control of this disease depends on the sensitivity and specificity of the diagnostic tests implemented for naturally infected samples, where parasitaemias are usually low. This study aimed to evaluate the analytical sensitivity and specificity of several primers for T. vivax detection in experimental infections and their implementation for the diagnosis of trypanosomosis in naturally infected bovine and ovine samples. Using a T. vivax Venezuelan isolate, five sets of primers were evaluated: TviSL1/2, ITS1CF/BR, TVMF/R, ILO1264/1265, TVWA/B. Additionally, we tested the PCR protocols using different DNA quantities. The best set of primers (ILO1264/1265) was used to detect T. vivax DNA from whole blood and buffy coat samples of 12 sheep (ovine) and 45 cattle (bovine) of small farms from Venezuela, and compared to the micro-haematocrite centrifugation technique (MHCT). The highest sensitivity was 0.0001 ng for ILO1264/1265 and TVWA/B primers. Using 100 ng of DNA extracted from the buffy coat and the ILO1264/1265 primers for trypanosomosis diagnosis from naturally infected samples, yielded 66.7% (8/12) and 35.7% (16/45) positives in ovine and bovine respectively. The percentage of positives samples increased to 83.3% (10/12) and 64.4% (29/45), with 300 ng in the assays. Contrary, using 300 ng of DNA extracted from the whole blood yielded only 50% (6/12) and 28.9% (13/45) of positives samples for T. vivax respectively. MHCT only detected the parasite in bovine samples with 17.8% (8/45) of positives. Based on our results, we recommend the use of the ILO1264/1265 primers and 300 ng of DNA extracted from the buffy coat for epidemiological studies of naturally infected animals. Moreover, detection of the parasite in ovine herds highlights a possible role of this host in the epidemiology of trypanosomosis in Venezuela.

New detection of the occurrence of trypanosomiasis in a bovine herd in a rural property in the state of Bahia/BA ­ case report / Nova detecção da ocorrência de tripanossomíase em rebanho bovino em propriedade rural no estado da Bahia/BA ­ relato de caso

This report aims to discuss the occurrence of protozoan infestation in a Girolanda cattle herd in the state of Bahia / BA. Bovine trypanosomiasis is a severe disease that is harmful to cattle, inducing large productive and economic losses. The animals are affected by protozoa of the genus Trypanosoma spp., giving rise to infestations in the vast majority of them in a silent and lasting way. In the Bahian rural property described, 10% of adult cows died and the rest of the animals showed clinical signs of anemia, drop in milk production, low body score, apathy, among others. Among the information obtained through the farm manager, who helped in the diagnosis and in ordering tests for the respective disease were: purchase of cattle from the region of the state of Minas Gerais and dubious management of oxytocin for improvements in milk production (suspected shared needles). Faced with the suspicion and in conjunction with the information obtained, laboratory tests and molecular tests were carried out to confirm the suspicion. After the examinations, it was found that the animals were affected by protozoa of the genus Trypanossoma vivax. The animals were treated with volume replenishers and drugs such as isometamidium chloride in a single dose calculated according to the body weight.

O presente relato tem por objetivo discorrer sobre a ocorrência da infestação protozoária em um rebanho bovino da raça Girolanda no estado da Bahia/BA. A tripanossomíase bovina é uma doença severa e prejudicial aos bovinos, induzindo-os a grandes perdas produtivas e econômicas. Os animais são afetados por protozoários do gênero Trypanosoma spp., dandoorigem a infestações em sua grande maioria de forma silenciosa e duradoura. Na propriedade rural baiana descrita, 10% das vacas adultas morreram e o restante dos animais apresentava sinais clínicos de anemia, queda da produção leiteira, baixo escore corpóreo, apatia, prostração, entre outros. Dentre as informações obtidas através do gerente da fazenda, que auxiliaram no diagnóstico e na requisição de exames para a respectiva doença estavam: compra de bovinos da região do estado de Minas Gerais e manejo duvidoso de ocitocina para melhorias na produção leiteira (suspeita de agulhas compartilhadas). Diante da suspeita e em conjunto com informações obtidas, foram realizados exames laboratoriais e testes moleculares para confirmar a suspeita. Após a realização dos exames, constatou-se que os animais estavam acometidos por protozoários do gênero Trypanossoma vivax. Os animais foram tratados com repositores de volume e fármacos como o cloreto de isometamidium em uma única dose calculada de acordo com o peso corpóreo.

A recombinant protein (MyxoTLm) for the serological diagnosis of acute and chronic Trypanosoma vivax infection in cattle.

Human trypanosomiases and animal trypanosomoses are caused by distinct protozoan parasites of the genus Trypanosoma. The etiological agents of bovine trypanosomosis (BT) are T. vivax, T. congolense, or T. brucei, whose acute infections are initially characterized by hyperthermia, following moderate to severe anemia, subcutaneous edema, lethargy, reduced milk production, progressive weight loss, enlarged lymph nodes, reproductive disorders and death. Animals that survive the acute phase might recover and progress to the chronic, often asymptomatic, phase of infection. Despite their low sensitivity due to the characteristic low parasitemia, simple and costless direct parasitological examinations are the preferred diagnostic methods for animals. Thus, most of the epidemiological studies of BT are based on serological techniques using crude antigen. In this study, we describe the use of the MyxoTLm recombinant protein as an antigen on serological assays. Anti-T. vivax IgM and anti-T. vivax IgG ELISA assays using purified MyxoTLm revealed specificity rates of 91.30 % and 95.65 % and sensitivity rates of 82.35 % and 88.23 %, respectively, being higher than reported for crude antigens. Also, MyxoTLm demonstrated a good performance to detect IgM (ROC curve area = 0.8568) and excellent performance to detect IgG (ROC curve area = 0.9565) when compared to a crude antigen. T. evansi crude antigen used in the indirect anti-T. vivax IgM ELISA reached 70.58 % sensitivity and 78.26 % specificity, and had a lower test performance (ROC curve area = 0.7363). When applied to the anti-T. vivax IgG ELISA, the crude antigen reached 82.35 % sensitivity and 69.56 % specificity, also presenting a low performance with area under the ROC curve of 0.7570. Therefore, the use of MyxoTLm as an antigen on serological diagnosis of BT revealed to increase the sensitivity and the specificity if compared to crude antigens.

Follow-up of dairy cattle naturally infected by Trypanosoma vivax after treatment with isometamidium chloride.

Trypanosoma vivax infections cause nonspecific clinical signs in cattle associated with aparasitemic intervals, making disease diagnosis a challenge. In Brazil, diminazene aceturate and isometamidium chloride (ISM) are available to treat bovine trypanosomosis. The objective of this study was to follow-up, by molecular and serological techniques, dairy cattle naturally infected by T. vivax after ISM treatment. Thirty cattle naturally infected with T. vivax received two applications of ISM, at a dosage of 1.0 mg/kg intramuscularly, on days 0 and 150. For T. vivax diagnosis, EDTA-blood and serum samples were evaluated on 0, 7, 15, 30, 60, 90, 120, 150, 180, 210, and 240 days after treatment PCR, Loop-mediated isothermal amplification (LAMP) and ELISA. Animals with persistent detection of T. vivax DNA by both PCR and LAMP were found and continuous detection of anti-T. vivax IgG antibodies by ELISA, suggesting the presence of T. vivax resistance to ISM. The combination of LAMP and ELISA tests can prevent misdiagnosis of the parasite clearance in treated cattle, contributing to better disease control. This is the first experiment that demonstrates the persistence infection of T. vivax under ISM treatment in a natural infected herd and evidence of ISM chemotherapy-resistant T. vivax in Brazil.

Follow-up of dairy cattle naturally infected by Trypanosoma vivax after treatment with isometamidium chloride / Acompanhamento de bovinos leiteiros naturalmente infectados com Trypanosoma vivax após tratamento com cloreto de isometamidium

Abstract Trypanosoma vivax infections cause nonspecific clinical signs in cattle associated with aparasitemic intervals, making disease diagnosis a challenge. In Brazil, diminazene aceturate and isometamidium chloride (ISM) are available to treat bovine trypanosomosis. The objective of this study was to follow-up, by molecular and serological techniques, dairy cattle naturally infected by T. vivax after ISM treatment. Thirty cattle naturally infected with T. vivax received two applications of ISM, at a dosage of 1.0 mg/kg intramuscularly, on days 0 and 150. For T. vivax diagnosis, EDTA-blood and serum samples were evaluated on 0, 7, 15, 30, 60, 90, 120, 150, 180, 210, and 240 days after treatment PCR, Loop-mediated isothermal amplification (LAMP) and ELISA. Animals with persistent detection of T. vivax DNA by both PCR and LAMP were found and continuous detection of anti-T. vivax IgG antibodies by ELISA, suggesting the presence of T. vivax resistance to ISM. The combination of LAMP and ELISA tests can prevent misdiagnosis of the parasite clearance in treated cattle, contributing to better disease control. This is the first experiment that demonstrates the persistence infection of T. vivax under ISM treatment in a natural infected herd and evidence of ISM chemotherapy-resistant T. vivax in Brazil.

Resumo Em bovinos, infecções por Trypanosoma vivax geram sinais clínicos inespecíficos que, associados a intervalos aparasitêmicos, faz com que o diagnóstico da enfermidade seja desafiador. No Brasil, somente aceturato de diaminazeno e cloridrato de isometamidum (ISM) estão disponíveis para o tratamento da tripanossomose bovina. Este trabalho teve como objetivo acompanhar bovinos leiteiros naturalmente infectados por T. vivax, após o tratamento com ISM por meio de técnicas moleculares e sorológica. Foram utilizados 30 bovinos naturalmente infectados com T. vivax, sendo estes tratados com duas aplicações de ISM, na dosagem de 1,0 mg/kg por via intramuscular profunda, nos dias 0 e 150. Foram avaliadas, para diagnóstico de T. vivax, amostras de sangue acrescido de EDTA e soro, colhidas nos 0, 7, 15, 30, 60, 90, 120, 150, 180, 210 e 240 dias após os tratamentos pela reação em cadeia da polimerase (PCR), amplificação circular isotérmica do DNA (LAMP) e ensaio de imunoabsorção enzimático (ELISA). Verificou-se a presença de animais com persistência na detecção de DNA de T. vivax pela PCR e LAMP, bem como detecção contínua de anticorpos IgG anti-T. vivax pelo método de ELISA, sugerindo a presença de resistência de T. vivax ao ISM. A combinação dos testes LAMP e ELISA pode evitar falsos diagnósticos da eliminação do parasita nos bovinos tratados, contribuindo para um melhor controle da doença. Este é o primeiro experimento que demonstra infecção persistente do T. vivax em rebanho naturalmente infectado, tratado com ISM, e evidencia possível resistência ao quimioterápico no Brasil.

Parasitological and clinical-pathological findings in twelve outbreaks of acute trypanosomiasis in dairy cattle in Rio de Janeiro state, Brazil.

In Brazil, infection in cattle was first reported in the state of Pará, in 1944, and the presence of the parasite has already been recorded in several states. The purpose of this study was to report the clinical-pathological aspects of a natural infection by T. vivax in dairy cattle in the state of Rio de Janeiro. Twelve outbreaks of the infection were diagnosed in 11 municipalities from April 2016 to October 2018. All properties had acquired cattle from states where the disease had already been recorded and it was found that needles for oxytocin administration had been shared. These outbreaks were studied by visiting the properties to perform anamnesis, clinical exams and collection of material for laboratory diagnosis. Laboratory diagnosis was performed through parasitological, molecular and histopathological techniques. Animals with confirmed diagnosis for T. vivax showed anemia, lack of appetite, decreased milk production, weight loss, weakness, abortion, diarrhea and neurological signs. The main histological lesions found were meningoencephalitis and lymphohistiocytic myocarditis. In the central nervous system, the lesions were more severe in the brain compared to the spinal cord, being progressively more severe in the rostro-dorsal direction. Also, they were more accentuated in the white matter compared to the gray matter. Due to nonspecific clinical signs, laboratory tests were key for diagnosis. Trypanosomiasis in cattle herds in the state of Rio de Janeiro, Brazil, is of great concern because of its potential to cause economic losses.

Epidemiological and molecular identification of Trypanosoma vivax diagnosed in cattle during outbreaks in central Brazil.

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.

Comparison of therapeutic efficacy of different drugs against Trypanosoma vivax on experimentally infected cattle.

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.