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La tripanosomosis bovina causada por Trypanosoma vivax tiene un gran impacto económico en la industria ganadera de los países tropicales. Debido a la escasa información existente sobre la respuesta inmunitaria inducida por este parásito en rumiantes, se planificó la presente investigación con la finalidad de evaluar y comparar la respuesta inmunitaria de ovinos infectados experimentalmente con dos aislados de T. vivax. Ambos aislados fueron obtenidos de diferentes zonas geográficas de Venezuela (TvLIEM176 proveniente del estado Trujillo y TvMT1 del estado Monagas). Tres ovinos fueron inoculados con cada aislado y tres sirvieron como control para un total de nueve animales. Cada tres días (d), durante un periodo de 60 d se tomaron muestras de suero para realizar la prueba de ELISAi (para determinar la presencia de anticuerpos anti-Trypanosoma spp.), y sangre para evaluar la parasitemia y realizar un contaje total y diferencial de leucocitos. Los animales del grupo inoculado con el aislado TvMT1 mostraron mayores niveles de anticuerpos antitripanosoma que los animales del grupo TvLIEM176, mientras que la parasitemia se comportó de manera inversa, ya que el aislado TvLIEM176 produjo mayores niveles de parasitemia que TvMT1. Además, el aislado TvLIEM176 originó linfopenia durante los d 12 al 36 postinfeccion, mientras que el aislado TvMT1 no. Por lo tanto, se demostró que la respuesta inmunitaria humoral de los dos aislados de T. vivax en ovinos fue diferente, la cual puede deberse a una inmunosupresión causada por el aislado TvLIEM176 al inducir linfopenia. Bovine trypanosomosis caused by Trypanosoma vivax, has a significant negative impact on livestock. Due to the limited information on the immune response against this parasite in ruminants, the present investigation was undertaken with the aim to evaluate and compare the immune response of sheep experimentally infected with two T. vivax isolates. The isolates were obtained from different geographic areas of Venezuela (TvLIEM176 from Trujillo State and TvMT1 from Monagas State). Three sheep were inoculated with each isolate and three others were used as controls for a total of nine animals. Every three days (d), during a period of 60 d, blood and serum samples were taken to determine anti-Trypanosoma spp. antibodies (by iELISA), parasitemia, white blood cell count and a leukocyte profile. TvMT1inoculated animals showed higher levels of antibodies than TvLIEM176-infected animals, although parasitaemia behaved inversely. The TvLIEM176 isolate produced higher levels of parasitemia than the TvMT1 isolate. In addition, lymphopenia was observed in TvLIEM176-infected sheep from day 12 to 36 postinfection, while lymphopenia was not shown in TvMT1-infected animals. It was demonstrated that the humoral immune response against both T. vivax isolates in sheep was different, which may be related to immunosuppression caused by TvLIEM176 isolate due to production of lymphopenia. 361-367 areyna@inmunobiologia.net.ve

Bovine trypanosomosis, caused by Trypanosoma vivax has a significant negative impact on livestock. This research was performed with the aim of determining the immunoreactive proteins present in T. vivax. Thus, five sheep were experimentally infected with T. vivax TvZC1 isolate. Animal number 1 was used as the source of the trypanosomes and to prepare the soluble extract of parasites. Sheep numbers 2 to 5 were monitored for eight weeks and sera was obtained every two weeks for immunodetection. Parasites obtained from animal 1 were analyzed for T. vivax proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot (WB). The WB analysis showed three immunodominant proteins with a molecular mass of 42, 64 and 72 kDa, approximately. The 64 kDa protein was recognized by every animal during the complete infection period. The 72 kDa protein only was detected by animals 2, 3 and 5 during the infection course, whereas in animal 4 it was only detected during the 6th and 8th weeks post infection. Moreover, the 42 kDa polypeptide was slightly immunorecognized by animals 2, 3 and 4 during the complete infection period, but in animal 5 only it was identified during the 2nd week post infection. It is assumed that the 42 kDa protein is the VSG of T. vivax, which resulted in a low antigenic capacity, contrary to the protein of 64 kDa which showed a high antigenic capacity and cross-reactivity with Trypanosoma evansi.

BACKGROUND: Both endo- and ectoparasites pose a great challenge to the health of pigs worldwide, placing a significant burden on low-resource countries where veterinary care is minimal. As part of a larger clinical trial assessing the use of ivermectin (IVM) mass drug administration to humans and pigs for the control of malaria vectors in the Mopeia district in Mozambique, a longitudinal study to assess the impact of IVM administration on pig health was performed. METHODS: Beginning in March 2022, IVM was administered to pigs in the intervention area once a month for three consecutive months. Seventy pigs from the treatment group and 70 pigs from the control group were randomly selected for inclusion in the study. Fecal samples were collected monthly for three months and analyzed for the presence of strongyle eggs, strongyle eggs in the larval stage (strongyles – larval) and Ascaris suum using the modified McMaster test. Fecal samples were also collected two weeks after each dose of IVM was given to pigs in the treatment group for determination of a fecal egg reduction count. Juvenile pigs were measured twice a month for the first 3 months of the study, then once monthly for another three months. Visual exam for ectoparasites was performed on all pigs for the presence of ticks, lice or scabies at the same time points. RESULTS: Overall, 55% [95% CI: 48-62%] of pigs were positive for Ascaris suum, 95.2% [95% CI: 91-98%] were positive for strongyle eggs, and 72.5% [95% CI: 65.5-79%] were positive for strongyle – larval. A significant difference in the ivermectin treatment group was only seen one month after the second dose of ivermectin was administered: pigs in the treatment group had a 23.6% lower prevalence of strongyles (p = 0.003) and 18% lower prevalence of strongyles – larval (p = 0.03). Pigs in the treatment group also had lower EPG for Ascaris suum (diff = 102 EPG; p = 0.006), strongyles (diff = 642 EPG; p < 0.001), and strongyles - larval (diff = 217 EPG; p < 0.001). Analysis of covariance regression found no significant difference(P>0.05) in average daily weight gain (ADG) between the treatment and control groups. CONCLUSION: IVM delivered once monthly for three months has a small impact on pig health. To counteract the multiple health challenges pigs face in these settings, different dosing schedules along with education on husbandry issues related to nutrition and sanitation should be investigated in order to maximize impact on pig health. Master of Science A study was conducted in rural Mozambique in the district of Mopeia to determine the effectiveness of ivermectin against common parasites of swine when administered to pigs. The study began in March of 2022, at the beginning of rainy season, and ivermectin was given to pigs once a month for three months. Pigs were visited twice a month for the first three months, and then once a month for another three months. At various time points, fecal samples were collected, pigs were examined for evidence of ectoparasites (ticks, lice and scabies infestation), and young pigs were measured to determine their rate of growth. Fecal samples were analyzed for the presence of common internal parasites (endoparasites) affecting pigs in the area. The burden of endo and ectoparasites was estimated before any ivermectin was administered, and then compared in treated and untreated pigs over the course of the study. Similarly, the effect of ivermectin on growth rates in young animals was determined. The results of this study found that there was a high burden of common endoparasites in pigs in the Mopeia district, which was only minimally affected by the use of ivermectin delivered once a month. Among the treated pigs, a fecal egg count reduction test suggests that these parasites are potentially resistant to ivermectin, although other issues may be responsible for these results. The burden of ectoparasites was generally low (