Humoral immunity is not altered in overweight pregnant Crioulo mares / Imunidade humoral não é alterada em éguas Crioulas gestantes com sobrepeso

Both pregnancy and obesity can influence significant changes in the immune system. On this basis, the present study proposes to evaluate the humoral immune response of overweight pregnant mares in response to a commercial vaccine. Thirty pregnant Crioulo mares were separated according to body condition score (BCS) into overweight (BCS≥7/9) or lean-control (BCS= 5-6/9). In each group, the animals were subdivided into vaccinated and controls. The mares were vaccinated against EHV-1 in two doses spaced 21 days apart and had their blood collected monthly, for five months, for antibody evaluation. Both vaccinated groups had an increase in specific neutralizing antibodies after the vaccine. However, after the second dose, there was no increase in antibodies in any of the groups. Vaccinated overweight and lean-control mares did not differ at any time point. Therefore, this study demonstrated that obesity does not influence the humoral immune response in pregnant Crioulo mares.(AU)

Tanto a gestação quanto a obesidade podem influenciar o desenvolvimento de alterações significativas no sistema imune, portanto, o presente estudo teve como objetivo avaliar a resposta imune humoral de éguas gestantes com sobrepeso em resposta a uma vacina comercial. Trinta éguas Crioulas gestantes foram separadas de acordo com o escore de condição corporal (ECC) em éguas com sobrepeso (ECC≥7/9) e éguas controles (ECC=5-6/9) e, ainda, em cada grupo, os animais também foram separados em vacinados e controles. As éguas foram vacinadas contra o EHV-1 em duas doses com intervalo de 21 dias, sendo realizadas coletas de sangue mensalmente durante cinco meses para avaliação de anticorpos neutralizantes. Ambos os grupos vacinados tiveram aumento de anticorpos neutralizantes específicos após a vacina, porém, após a segunda dose, não foi observado aumento de anticorpos em nenhum dos grupos. Nenhuma diferença foi observada entre éguas vacinadas com sobrepeso e as éguas controles em nenhum momento. Assim, este estudo demonstrou que a obesidade não é um fator que influencia a resposta imune humoral de éguas Crioulas gestantes.(AU)

Immune response of adult horses, pregnant mares and foals to an experimental vaccine with recombinant EMA-2 protein of Theileria equi.

Equine theileriosis, caused by the Theileria equi protozoan, is a disease of worldwide importance. T. equi expresses surface proteins, of which the EMA-2 protein is a promising antigen for vaccine use. The aim of this study was to evaluate the immune response of adult horses, pregnant mares, and foals to an experimental EMA-2 protein of recombinant T. equi vaccine. A total of 46 horses were used in this study for vaccine trials and challenges. Twelve geldings, 14 pregnant mares, and 14 foals were divided into vaccinated and control groups. Total serum specific anti-rEMA-2 IgG, IgG subclasses, and transcription of cytokines related to the immune response were evaluated. For the vaccine challenge, six six-month-old foals were divided into vaccinated and control groups. For the challenge, blood from a horse with theileriosis was transfused to the foals. Geldings and pregnant mares maintained anti-rEMA-2 IgG levels at 130 and 140 days after vaccination, respectively. The most-detected IgG subclasses in vaccinated were IgG3/5, IgG4/7, and IgG1. IL2, IL10, IL12, IL17, IFN-γ, and TNF-α were the most-transcribed cytokines in PBMCs of vaccinated horses stimulated with rEMA-2. Challenge with T. equi demonstrated that vaccinated foals had an increase of 33% in total IgG four days after blood transfusion, while control foals had no significant response, suggesting that vaccine antibodies may have recognized EMA-2 protein of the native T. equi antigen. T. equi recombinant EMA-2 was shown to be a promising vaccine antigen by inducing humoral and cellular immunity similar to that observed in natural parasite infections.

Occurrence of Gasterophilus spp. in weanling foals in southern Brazil

The occurrence of gastrointestinal myiasis caused by Gasterophilus spp. larvae (Diptera: Oestridae) in adult horses has been widely characterized, however data on natural infestation in young foals have been lacking. This observation may be related to the absence of conclusive diagnosis in these individuals, most likely due to logistical or financial constraints. Gastric ulceration is a problem and a significant cause of morbidity in foals, particularly during the weaning stage; therefore, gasterophilosis should be included in the differential diagnosis. The primary purpose of this study was to determine the prevalence of gasterophilosis in 4- to 6-month-old weanling foals. Seventy-one healthy weanling foals were enrolled in the study. Physical assessment blood sampling and was completed in all foals before the commencement of the experiment. Gastroscopy examinations were performed under sedation (Detomidine 0.01 - 0.02 mg/kg) with a flexible endoscope inserted through nasogastric via. The lumen of the stomach was examined in order to search for botflies' larvae. Following gastroscopy, foals were classified into 2 groups based on the presence of Gasterophilus spp. larvae in their stomachs: 1) Infected and 2) Not Infected. Infected foals received a single dose of commercial trichlorfon and albendazole equine oral gel and were stalled for 24 h. The passed feces were thoroughly examined, searching for elimination of larvae. A total of 64% of the foals (n = 45/71) harbored Gasterophilus spp. larvae in the stomach. Mild hyperemia in the gastric mucosa was observed in the attachment sites of the parasites. Physical assessment and hematological parameters' data were analyzed with Shapiro-Wilk normality test. Comparison between groups for clinical signs, hematological parameters and Gasterophilus spp. infection rates were evaluated using the Kruskal-Wallis test or Student's t-test. Statistical significance was set at P < 0.05. There were no statistically significant variations in physical and hematological parameters between foals that were affected and those that were not infected. The larvae found in the feces were subjected to morphological examination, which confirmed the diagnosis of Gasterophilus intestinalis. No systemic clinical indications compatible with Gasterophilus spp. infestation were seen, as described in previous studies of horses infected with the parasite. No botfly eggs were observed in the hair of evaluated foals. During gastroscopy, mild hyperemic lesions in the gastric mucosa were observed in the larvae fixation sites. Although no changes in clinical or hematological parameters were noted, the confirmation of parasite presence is a cause for concern due to horses' tolerance for low infestation levels and poor diagnosis. Additionally, the presence of this myiasis in foals may be a significant stressor during the weaning period and should be included in the differential diagnosis of recurring abdominal pain. Furthermore, infected foals might be a reservoir for the parasite and, contribute to the elimination and spread of the larvae in the environment. Thus, inclusion of young horses in deworming protocols targeted to botfly larvae is needed. This is the first report of Gasterophilus intestinalis myiasis in foals in Brazil. Further research is necessary to fully understand the epidemiology and prevalence of this condition in young horses in Brazil, based on the findings of this study.(AU)

Antigenicity assessment of the Theileria equi merozoite antigen (EMA-2) expressed in Pichia pastoris in mice and horses.

Equine theileriosis is a severe equine disease caused by the protozoan Theileria equi, which is prevalent in tropical and subtropical areas. In this study, a recombinant equi merozoite antigen-2 (rEMA-2) of T. equi was used as an immunogen. Two groups of 10 mice each were divided into control and vaccinated groups. Sixty mares seronegative for theileriosis were divided in two groups, one vaccinated and another group as a control animal. Mice and mares of the vaccinated groups were inoculated with 150 µL of the vaccine containing 50 µg of rEMA-2 and 2 mL of the vaccine containing 200 µg of rEMA-2, respectively, at days 0 and 21. The immunogenicity of rEMA-2 was evaluated by ELISA and fluorescent antibody test (IFAT) using serum from vaccinated mice, mares and antigenicity in naturally infected horse. At every point throughout the ELISA study, there were significant differences between the vaccinated and control groups (p < 0.05). The vaccine induced 3- and 4-fold IgG increases in mice at the 14th and 28th day, respectively, compared to the control group. The horses' IgG dynamics showed a significant (p < 0.05) increase in the total IgG titer as early as day 7, which increased until day 28 at which time a more significant (p < 0.001) IgG titer was observed. In evaluating the isotypes, we observed a trend similar to that of total IgG, where IgG(T) (IgG3-5) were significantly (p < 0.05) more elevated than the other isotypes analyzed, followed by IgGb (IgG4-7) and IgGa (IgG1). Positive fluorescence was detected by IFAT, suggesting that the protein is immunogenic and conserves some epitopes identical to the native T. equi antigens present in the equine blood smear. Thus, our results suggest that rEMA-2 can be a promising vaccinal antigen.

Development of a weight-estimation model to use in pregnant criollo-type mares / Modelo para estimativa de peso em éguas gestantes mestiças crioulas

ABSTRACT: The aims of this study were: 1) to compare the tape weight and associated weight-estimation formula to evaluate weight gain in pregnant mares, and 2) to develop a mathematical model to estimate the weight of pregnant mares using body measurements. Thirty-four criollo-type mares were evaluated every two weeks during the middle and late pregnancy. The mares were weighed on a livestock scale, and we estimated body weight using tape weights and an associated body-weight estimation formula. Also, heart-girth circumference (heartgirth) and abdominal circumference were measured; the latter at the 12th intercostal space (12th ICS) and 18th rib (18th Rib), to use in a mathematical model to estimate the weight of pregnant mares. Observations were divided into three periods of pregnancy: 5th to 7 h month, 7th to 9 h month, and 9th to 11th month. Mares in late pregnancy showed an increase in actual weight and an increase in 12th ICS and 18th Rib measurements. Tape weight and body-weight estimation formula underestimated the weight of pregnant mares. However, the regression model using heart-girth circumference, 12th ICS, and 18th Rib measurements showed high correlation (r2 = 0.87, P<0.001) with actual weight. Finally, the alternative methods usually used in horses are not accurate to estimate body weight in pregnant mares. In conclusion, the regression model Y=-540.143 + (heartgirth x 3.068) + (12th ICS x 1.278) + (18th Rib x 0.944) can be used to estimate body weight in pregnant mares from the 5th to 11th months of pregnancy.

RESUMO: Este estudo teve como objetivos: 1) comparar a utilização dos métodos alternativos fita de pesagem e peso metabólico em éguas gestantes e; 2) desenvolver um modelo matemático para estimar o peso de éguas gestantes, baseado em medidas corporais. Trinta e quatro éguas foram avaliadas quinzenalmente durante o terço médio e final da gestação. Foi realizada a pesagem em balança comercial; a mensuração com a fita de peso para equinos; o cálculo do peso metabólico; as medidas de perímetro torácico (Ptorac); a mensuração abdominal no décimo segundo espaço intercostal (12EI) e na décima oitava costela (18Cost). As observações foram divididas em três períodos gestacionais: Período de 5 a 7 meses, Período de 7 a 9 meses e Período de 9 a 11 meses. As éguas demonstraram incremento no peso na balança e na mensuração abdominal no 12EI e 18Cost no terço final da gestação. A utilização da fita de pesagem e o cálculo de peso metabólico subestimaram o peso na balança em éguas gestantes. O modelo de regressão utilizando o Ptorac, 12EI e 18Cost apresentou alta correção (r2=0,87; P<0,001) com o peso na balança. Observou-se que os métodos alternativos de pesagem, usualmente utilizados, não apresentaram a mesma eficiência em éguas prenhes. Pode-se concluir que o modelo de regressão Y=-540,143+(Ptorac X 3,068) + (12EI X 1,278) + (18Cost X 0,944) pode ser utilizado para mensurar o peso em éguas gestantes a partir do 5º mês de gestação.