Occurrence of serological reactions for Leptospira spp. in donkeys and mules from Minas Gerais, Brazil.

Research concerning leptospirosis in donkeys and mules has been neglected around the world. Therefore, the aim of this study was to investigate the epidemiological situation of the prevalence of anti-Leptospira spp. antibodies in donkeys and mules from the state of Minas Gerais, Brazil. Blood serum samples were collected from 180 animals (109 donkeys and 71 mules) in two rural properties from the state of Minas Gerais, Brazil, and then submitted to a microscopic agglutination test (MAT). Urea and creatinine values were also quantified. Epidemiological variables such as age, breeding system, contact with other animal species, source of water and food, vaccination against leptospirosis, presence of reproductive alterations, and rodent control were also investigated. From 180 samples collected, 39 (21.67%) showed positive results in the MAT, at a dilution ≥ 1:100. Some animals were reactive for more than one serovar. The serovar Tarassovi was the most frequent (14.07%), followed by Hardjo (11.85%) and Wolffi (11.11%). There was a statistically significant difference between animals from 0 to 3 years of age reactive in the MAT in comparison to the other age groups. Most of the animals had urea and creatinine concentrations within the acceptable reference limit; however, there was a significant increase in creatinine levels in some of the test animals. The studied properties showed differences in some epidemiological aspects such as vaccination of the animals, presence of reproductive problems in the herd, and rodent control. Such aspects pointed as risk factors that may influence the frequency of positive serological results in property 1. The present study demonstrated that the prevalence of leptospirosis in donkeys and mules is high and several serovars are being maintained by these animals, representing a potential public health risk.

Vertical migration of Haemonchus sp. infectant larvae on Stylosanthes spp. and Brachiaria brizantha (Syn. Urochloa brizantha) cv. Marandu forage

The present work aimed to evaluate the influence of Stylosanthes spp. (Campo Grande© styles) and Brachiaria brizantha cv. Marandu in the vertical migration of Haemonchus spp. infective larvae, in the region of Uberlândia, Minas Gerais. Seeds of Stylosanthes spp. and Brachiaria brizantha cv. Marandu were planted in 50 pots of five liters (20 cm diameter) evenly disposed in an area of the Capim Branco Experimental Farm, Federal University of Uberlândia. When both species reached the minimum height of 20 cm, the pots were experimentally contaminated with sheep feces coprocultures. Samplings were performed, with complete removal of the vegetal material contained in the pots, on days one, three, six, 10 and 14 after contamination. Nematoids were recovered from the plant samples by thermo and hydrotropism, counted under an optical microscope and identified. For statistical analysis, the data were analyzed in a completely randomized design (DIC) in a 2X5 factorial scheme (two fodder species X 5 collection dates). No effect of the forage species was observed on the number of L3 of Haemonchus sp. recovered in the feces (p = 0.7790), upper stratum (p = 0.1755) or lower stratum (p = 0.7883) of the forage, however, there was a significant decrease in the number of L3 found with the passing of the days. When comparing the mean L3 recovered in the upper (0.06±0.31 L3) and lower (2.94±0.39) strata, a higher number of larvae was observed in the lower stratum (p < 0.0001). Therefore, in both forage species studied, the upper stratum of the plants, preferably pastured by the animals, remained with less contamination of infective larvae and the contamination tended to decrease over the days.

Evaluation of response to anti-leptospira bacterin vaccination in pregnant ewes and the passive transfer of antibodies to their offspring / Avaliação da resposta à vacinação com bacterina anti-leptospira em ovelhas gestantes e a transferência passiva de anticorpos a suas crias

Leptospirosis in sheep is often underestimated, and leads to great economic losses for the sheep farming industry. The aim of this study was to evaluate the humoral immune response in pregnant ewes, after the injection of a commercial polyvalent vaccine for leptospirosis, and to observe the transmission of anti-Leptospira antibodies through the colostrum to the offspring. For this, 24 pregnant ewes were vaccinated for leptospirosis. Blood samples were collected prior to vaccination and then 7, 14, 21, 28, 35, 42 and 49 days after vaccination. In order to evaluate passive immunity transfer, blood samples of 32 lambs were collected during the first 48 hours after birth, and another collection was performed 10 to 21 days after birth. The lambs were placed into 2 groups: Group A (n=16): singleton lambs; and group B (n=16): twins. The sera samples were submitted to the Microscopic Agglutination Test (MAT), in which 21 Leptospira serovars were tested. The results were analyzed in a descriptive form. The number of sheep reactive to MAT gradually increased until 21 days after vaccination, and decreased right after. Of all the serovars contained in the vaccine, the largest proportion of animals were seroconverted to Hardjoprajtino serovar, Serjoe serogroup. Anti-Leptospira antibodies transferred through colostrum to lambs were detected by MAT in the serum collected 24-48 hours after birth. It was observed that 65.6% (21 out of 32) of the lambs were reactive. In the subsequent collections that occurred from 10 to 21 days after birth, a decrease in the number of animals reactive to the MAT was detected. There was no significant statistical difference for the passive transfer of antibodies between single or twin lambs.

A leptospirose é uma doença frequentemente subestimada em rebanhos ovinos e leva a grandes prejuízos à ovinocultura. O objetivo deste estudo foi avaliar a resposta imune humoral em ovelhas gestantes, após imunização com uma vacina polivalente comercial contra leptospirose, bem como verificar a transmissão dos anticorpos adquiridos às crias, pelo colostro. Para isto, 24 ovelhas gestantes foram vacinadas. Amostras de sangue foram coletadas pré-imunização, bem como 7, 14, 21, 28, 35, 42 e 49 dias após. Para avaliar a transferência passiva de anticorpos, os 32 cordeiros que nasceram dessas ovelhas foram amostrados nas primeiras 48 horas após o nascimento, bem como com 10 e 21 dias de vida. Os cordeiros foram divididos em dois grupos: partos simples (Grupo A; n=16) e partos gemelares (Grupo B, n= 16). O soro sanguíneo foi submetido à prova de Soroaglutinação Microscópica (MAT), na qual 21 sorovares de Leptospira foram testados. O número de ovelhas reativas à MAT aumentou gradualmente até os 21 dias após imunização, com posterior decréscimo. De todos os sorovares presentes na vacina, a maior parte dos animais soroconverteu para o sorovar Hardjoprajtino, do sorogrupo Serjoe. Anticorpos anti-Leptospira passaram pelo colostro e puderam ser detectados no soro dos cordeiros entre 24 e 48 horas após o nascimento. Foi observado que 65,5% (21 de 32) cordeiros foram reativos. Em coletas subsequentes, realizadas 10 e 21 dias após o nascimento, houve um decréscimo no número de animais reativos à MAT. Não houve diferença significativa na transferência de anticorpos entre cordeiros de partos simples e gemelares.