First report of Strongyloides sp. (Nematoda, Strongyloididae) in Lutreolina crassicaudata (Didelphimorphia: Didelphidae) / Primeiro registro de Strongyloides sp. (Nematoda, Strongyloididae) em Lutreolina crassicaudata (Didelphimorphia: Didelphidae)

Abstract The present study reports the first case of the presence of the intestinal nematode Strongyloides sp. in fecal examinations of a male Lutreolina crassicaudata, considered a synanthropic marsupial species with zoonotic potential. The Willis technique was used for the diagnosis. Presence of typical eggs of Strongyloides species in feces was detected. A fecal culture was performed to obtain larval stages, free-living adults and infective third stage larvae (L3) of this nematode after seven days, which was morphologically identified as Strongyloididae. This is the first report of infection by Strongyloides sp. in a tick-tailed opossum from Brazil.

Resumo O presente estudo relata o primeiro registro da presença do nematódeo intestinal Strongyloides sp. em exames de fezes de um macho de Lutreolina crassicaudata, considerado um marsupial sinantrópico com potencial zoonótico. A técnica de Willis foi empregada no diagnóstico. Presença de ovos típicos de Strongyloides spp. foi detectada nas fezes. Uma coprocultura foi realizada para obtenção de estágios larvais, adultos de vida livre e larvas infectantes de terceiro estágio (L3) deste nematódeo após sete dias, os quais foram identificados morfologicamente como Strongyloididae. Este é o primeiro relato de infecção por Strongyloides sp. em uma cuíca de cauda grossa do Brasil.

First report of Strongyloides sp. (Nematoda, Strongyloididae) in Lutreolina crassicaudata (Didelphimorphia: Didelphidae).

The present study reports the first case of the presence of the intestinal nematode Strongyloides sp. in fecal examinations of a male Lutreolina crassicaudata, considered a synanthropic marsupial species with zoonotic potential. The Willis technique was used for the diagnosis. Presence of typical eggs of Strongyloides species in feces was detected. A fecal culture was performed to obtain larval stages, free-living adults and infective third stage larvae (L3) of this nematode after seven days, which was morphologically identified as Strongyloididae. This is the first report of infection by Strongyloides sp. in a tick-tailed opossum from Brazil.

Influence of protein supplementation during late pregnancy and lactation on the resistance of Santa Ines and Ile de France ewes to Haemonchus contortus.

This experiment aimed to evaluate the effect of periparturient metabolizable protein (MP) nutrition on resistance to Haemonchus contortus in single rearing Ile de France and Santa Ines ewes. The restriction-fed iso-energetic diet was calculated to provide either 0.8 (low MP diet) or 1.3 (high MP diet) times MP, from three weeks before parturition until eight weeks into lactation. The ewes were experimentally infected with 1000 H. contortus infective larvae (L3) three times a week (Mondays, Wednesdays and Fridays), starting five weeks before the predicted date for parturition until a total of 15,000 L3 had been administered. While both breeds showed elevated fecal egg counts (FEC), these values were significantly lower for Santa Ines ewes than Ile de France ewes, but were independent of level of MP feeding. The latter also did not affect lamb weight gain and ewe body weight variation in each breed. Packed cell volume and total plasma protein for Santa Ines in all periods were significantly higher than those for Ile de France ewes (P<0.01) but were not affected by nutrition. In contrast, levels of serum IgG and IgA antibodies against somatic H. contortus infective larvae and adult antigens were similar between breeds but higher in animals that received high MP diets (P<0.05). The reduced body score of ewes at the beginning of the experiment probably influenced their high susceptibility to incoming larvae. Since, unexpectedly, MP scarcity was not achieved in this experiment, our data support the view that Santa Ines ewes are more resistant to H. contortus than Ile de France ewes.

Immune response and performance of growing Santa Ines lambs to artificial Trichostrongylus colubriformis infections.

This study was carried out to evaluate the immune response and the impact of Trichostrongylus colubriformis infections on the performance of growing Santa Ines lambs. Thirty male lambs, 3-4 months of age, were maintained in individual pens and restrictively randomised by weight into 3 treatment groups: (1) infected group, artificially infected with 2500 T. colubriformis larvae, three times a week, for 13 weeks, and fed ad libitum; (2) Pair-Fed Group, non-infected and fed with the same amount of food consumed by the infected animal of the same class on the previous day; and (3) control group, non-infected and fed ad libitum. Refused feed was weighed daily to assess the food intake of each lamb. Animals were weighed weekly and blood and fecal samples were collected. At the end of the trial, all lambs were euthanized to determine worm burden and collect intestinal tissues and mucus samples for histological and immunological analysis. The infected group presented eosinophilia, increased number of inflammatory cells in the mucosa, in addition to an increased production of specific immunoglobulins against T. colubriformis, which partially prevented the establishment of infective larvae. As a consequence of parasitism, the infected lambs presented reduced serum albumin concentrations and demonstrated severe small intestine lesions, such as villous atrophy and epithelial erosion, which impaired the digestion and absorption of nutrients, causing a significant loss in performance. The infected group presented a 37% reduction in daily weight gain (107.26 ± 10.8 g/day), when compared with the control group (171.07 ± 7.15 g/day). The infected lambs also demonstrated the worst food conversion, i.e., each animal needed to consume on average 10.05 ± 0.52 kg of food to gain 1 kg live weight. The voluntary hay intake depression in infected animals was small, and statistical difference (P<0.01) was seen only on two occasions (ninth and 12th weeks), in comparison with the control group. In conclusion, Santa Ines lambs infected with T. colubriformis demonstrated a reduction in performance, caused by the damages produced by the adult nematodes in intestinal mucosa, and also by the immunopathological changes associated with the infection.