Infections by Trypanosoma vivax cause great losses to livestock in Africa and Central and South Americas. Outbreaks due this parasite have been occurred with increasing frequency in Brazil. Knowledge of changes caused by T. vivax during the course of this disease can be of great diagnostic value. Thus, clinical signs, parasitemia, hematologic and biochemical changes of cattle experimentally infected by this hemoparasite were evaluated. Two distinct phases were verified during the infection – an acute phase where circulating parasites were seen and then a chronic phase where fluctuations in parasitemia were detected including aparasitemic periods. A constant reduction in erythrocytes, hemoglobin and packed cell volume (PVC) were observed. White blood cells (WBC) showed pronounced changes such as severe neutropenia and lymphopenia during the acute phase of the illness. Decreases in cholesterol, albumin, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and increases in glucose, globulin, protein, and alkaline phosphatase (ALP) were observed. The “Lins” isolate of T. vivax showed pathogenicity for cattle, and intense parasitemia was detected in the early stages of infection. Circulating parasites were detected for about two months. The most evident laboratory abnormalities were found in WBC parameters, including thrombocytopenia.

Livestock infections by Trypanosoma vivax have been occurring with increasing frequency, mainly due to the presence of animals with subclinical infections and without apparent parasitaemia, making diagnosis challenging. The aim of the present study was to evaluate several techniques used for T. vivax diagnosis in order to assess the best way of using them during the course of the disease. Molecular methods demonstrated higher rates of detection than parasitological methods, detecting 33 of the 54 (61.1%) known positive samples, while the hematocrit centrifugation technique (best parasitological test) detected only 44.4%. The serological methods, IFAT and ELISA, detected seropositivity in 51 of the 54 (94.4%) and 49 of the 54 (90.7%) known positive samples, respectively. Despite being highly sensitive, the latter only demonstrates exposure to the infectious agent and does not indicate whether the infection is active. The present study was the first to use the qPCR for a South American isolate, improving disease detection and quantification. Furthermore, the analyses revealed that the patent phase of the disease may extend up to 42 days, longer than previously reported. The combination of several diagnostic techniques can lower the frequency of false negative results and contributes toward better disease control.

Parasitic otitis in cattle is normally caused by nematodes of the genus Rhabditis spp. and is a common problem in Gir breed. Parasitic otitis can cause premature culling and even death of animals. Despite its importance, there is no effective standardized treatment protocol for this condition. The objective of this study was to evaluate two treatments for parasitic otitis caused by Rhabditis spp. in Gir cattle. The external left ear of the animals was washed with 2% boricated alcohol, while the right ear received topical application of Triclorfon, allantoin and zinc oxide paste. The treatments were performed weekly in the first month and monthly over the next two months. Monthly, the ears of all animals were washed under pressure with a physiological solution before treatment. The recovered solution was analyzed, and the number of nematodes counted. Neither treatment was effective in reducing the number of nematodes recovered or the otitis score, but weekly treatment seemed more promising, independent of the drug used.

Trypanosoma vivax outbreaks have been reported with increasing frequency worldwide, causing significant economic losses in livestock. Though several studies have suggested that cytokine responses may influence infection caused by Trypanosoma sp., their exact role remains unclear and may vary according to the animal species and parasite strain. The present study aimed to evaluate cytokine expression of peripheral blood cells from three Girolando dairy cows experimentally infected with T. vivax. For this purpose, blood samples were collected prior to the inoculation on the day of inoculation (D0), the day after inoculation (D1), and then every seven days up to 119 days after infection (DAI). Each animal presented a unique pattern of cytokine expression. While a tendency of a Th1 cytokine response was observed during the patent phase (presence of circulating parasites), an increase of Th2 cytokine expression was found at the beginning of the sub-patent phase (low parasitaemia or aparasitaemic periods). In animals that presented a better control of parasitaemia, IL-6 and IFNγ increased during most of the trial period. On the other hand, the cow that presented reduction of IL-1β, IL-2, and TNFα during the entire period did not control parasitaemia properly. A balance between the Th1 and Th2 profile is beneficial for parasite control and animal health. The results found in the present study are a first step towards elucidating the dynamics of cattle’s inflammatory response against T. vivax, requiring future studies focusing on the role of key cytokines on the controlling of parasitaemia in different stages of bovine trypanosomosis.

Objetivo. El objetivo de este estudio fue evaluar la asociación in vitro del hongo Duddingtonia flagrans (AC001) e ivermectina en el control de nematodos gastrointestinales de terneros búfalo. Materiales y métodos. Se formaron cuatro grupos experimentales en microtubos, con cinco réplicas para cada grupo: G1 (nematodos + AC001), G2 (nematodos + ivermectina 1%), G3 (nematodos + AC001 + ivermectina 1%) y G4 (nematodos + agua destilada). Para cada grupo, después de 36 horas de interacción se leyó el contenido de los microtubos mediante microscopía óptica, contabilizando el número de nematodos por grupo. Resultados. Hubo una reducción larvaria significativa de los grupos tratados, con los siguientes porcentajes con relación al G4 (control): G1: 43,7%; G2: 82,3% y G3: 65,7%. También se observó que la asociación in vitro de D. flagrans con ivermectina fue más efectiva en la reducción de L3 en comparación con el uso aislado de este hongo. Conclusiones. Se concluyó que el uso conjunto de D. flagrans con ivermectina puede potenciar la eficacia del control biológico de los nematodos gastrointestinales de los búfalos, previendo su uso en las condiciones naturales de la cría de búfalos.