Toxocara canis: larval migration dynamics, detection of antibody reactivity to larval excretory-secretory antigens and clinical findings during experimental infection of gerbils (Meriones unguiculatus).

In this study, Mongolian gerbils were used to analyse features of Toxocara infection that included larval migration, humoral immune responses to Toxocara canis excretory-secretory antigens (TES) and aspects of host physiology. At day 10 post-infection (p.i.) most larvae were in the intestine and the lungs while later the total number of larvae was higher in the carcass tissue; the number of larvae per gram of tissue was lower elsewhere other than in the brain. Infected animals showed several neurological abnormalities, an early increase in leukocyte and neutrophil levels, two peaks of peripheral eosinophilia (5 and 40 d.p.i.) and high antibody levels against TES in the circulation and in the vitreous humor. A sequential recognition of eight T.canis larval antigens with MW from 24 to 200 kDa was detected by Western blot. The results obtained in this study further support the use of gerbils as an experimental model for systemic, ocular and cerebral toxocariasis.

Effect of selenium-vitamin E injection in selenium-deficient dairy goats and kids on the Mexican plateau

Foram conduzidos três experimentos para determinar a quantidade ótima da injeção de selênio-vitamina E (Se-vit E) para manter o nível aceitável do status de selênio no sangue de cabras e cabritos e determinar essa relação com o status sobre a taxa de mortalidade de cabritos. No primeiro experimento, 238 cabras foram usados em um dos três grupos durante o período do acasalamento: A1- controle, A2- 0,06mgSe+0,8UI vitE/kg de peso-vivo e A3- 0,125mgSe+1,7UI vitE/kg de peso-vivo. Não houve diferenças (P>0,05) entre os grupos para fertilidade e prolificidade. A concentração de Se no sangue não foi diferente entre os grupos que receberam Se-vit E e o controle antes da injeção e ambos os grupos mostravam deficiência de Se. Sessenta dias pós-tratamento houve tendência (P<0,05; 32%) de aumentar o nível de Se no sangue e não houve diferença entre os grupos A2 e controle. Houve diferença significativa (P<0,05; 103%) entre os grupos A1 e A2 e o grupo A3. No segundo experimento, 48 cabras foram divididas em quatro grupos: B1- controle, B2- 0,125mgSe+1,7UI vitE/kg de peso-vivo, B3- 0,25mgSe+3,4UI vitE/kg de peso-vivo e B4- 0,31mgSe+4,2UI vitE/kg de peso-vivo. O grupo B4 alcançou a concentração mais alta no terceiro mês depois da injeção (0,11ppm) e diminuiu depois de 100 dias, quando o valor foi apenas ligeiramente maior que os valores dos grupos B2 e B3, aos 135 dias da gestação. Os resultados dos grupos B2 e B3 foram ligeiramente mais altos que os do grupo B1 (P<0,05). No terceiro experimento, 194 cabritos (3 a 7 dias de idade), nascidos de cabras deficientes em Se, foram usados para comparar a efetividade da injeção de Se. Foram divididos em três grupos: C1- controle, C2- 0,3mgSe+4,2UI vitE/kg de peso-vivo e C3- 0,6mgSe+8,4UI vit E/kg de peso-vivo. A porcentagem de mortalidade foi mais alta em C1 (60%) e mais baixa nos grupos tratados com Se (22%). A concentração de Se no sangue no 20º após o início do tratamento aumentou rapidamente, de acordo com o nível de injeção de Se. A injeção com 0,3mgSe/kg de peso-vivo aumentou a concentração de Se no sangue em cabras gestantes e a dose foi efetiva para prevenir a doença de músculo branco e aumentar a sobrevivência dos cabritos até o desmame.

Main causes of mortalities in dairy goat kids from the Mexican plateau.

The causes of mortality in kids under extensive conditions in the Mexico plateau were studied. Perinatal mortality of kids (0-7 days) was lower (P<0.05) than mortality in the other age groups (8-90 days). The weights of the animals at death were extremely low, group (i) 0-7 days, 2.3kg; (ii) 7-30 days, 2.8kg and (iii) 30-90 days, 4kg. The principal finding at necropsy was white muscle disease (WMD). The WMD lesions, suggested selenium (Se) deficiency was present in 49 out of the 74 kids evaluated in this study (P<0.05). In many cases, muscular dystrophy was present with other pathological conditions. Enteric and pneumonic conditions were also important causes. In the small intestine villus atrophy was observed in 14 of the 25 kids that died with enteric problems between 8 and 30 days of age. Pneumonic lesions were present in 12 out of 74 kids. Miscellaneous conditions as starvation (five cases), hepatic conditions (three cases), omphalophlebitic infection (two cases) were also present in lower proportions. In conclusion, WMD was considered the main cause of deaths in goat kids between 8 and 90 days of age. Evaluation of Se status of soil, forages and goat tissues is recommended.

Diagnosis of selenium status in grazing dairy goats on the Mexican plateau.

The objective of this study was to determine the concentration of Selenium (Se) in soils, forages and the tissues of kids and does under extensive grazing conditions in two regions of the Tlaxcala state, Mexico (Carrillo Puerto and Ixtenco) in the dry and rainy season. There were no differences in the concentration of Se in soil (0.051 and 0.047ppm), pH of the soil (6.1 and 5.9), concentration of Se in the forage (0.052 and 0.075ppm) and blood serum of goats (0.02 and 0.021ppm) during the dry and rainy seasons, respectively. The Carrillo Puerto region had a significantly higher content of Se in the soil (31%), soil pH (7%), content of Se in forage (25.9%), and content of Se in blood serum of goats (16%) compared to the corresponding values obtained in Ixtenco. The mean concentration of Se in the serum of kids with clinical signs of white muscle disease, was significantly lower (36.3%) compared to the kids from the same farm that were apparently healthy. The results of this study suggest that soil, forages, and goats have a marginal Se status in both regions during the dry and rainy seasons. Further research is required to find the most appropriate method to correct the Se-deficiency in goats from these regions.

Effects of iproniazid on chick development.

New Hampshire eggs were injected with iproniazid into the yolk sac at day 2 of incubation by means of a tiny hole in the shell. A control group was injected with normal saline and a second group was left unopened. Iproniazid in the doses we used proved to be lethal for approximately 50% of the chick embryos, while we cannot demonstrate other developmental alterations, either in the macroscopical or in the serial histological study.