Gastrointestinal nematode infection and feeding behaviour of goats in a heterogeneous vegetation: No evidence of therapeutic self-medication.

The aim of this study was to identify modifications in the feeding behaviour of goats browsing a tropical deciduous forest (TDF) when natural gastrointestinal nematode (GIN) infection was suppressed. Continuous bite monitoring through direct observation was implemented in 12 Criollo goats (adults, non-pregnant) foraging for 4 h per day during the rainy season. In the first Period (P1, one observation point) all goats were maintained with natural GIN infection. In the second Period (P2, three observation points), goats were equally distributed into 2 groups: i) moxidectin treated group (TG) used in a suppressive scheme; and ii) naturally infected group (IG). For each observation point, goats were monitored at three timepoints per day (80 min each), for three consecutive days, to estimate their intake of dry matter (DM), condensed tannins (CT), crude protein, metabolizable energy and digestible DM. Live weight (LW), faecal samples and blood samples were obtained every 28 days to determine LW change, faecal egg counts (FEC) and packed cell volume (PCV). During P1 and P2, the TG and IG had similar LW change and PCV. During both periods, the intake of DM, CT and all macronutrients were similar for TG and IG. The suppression of GIN infection did not modify the feeding behaviour of goats. Therefore, a therapeutic self-medicative behaviour was not identified in Criollo goats browsing a TDF.

Factors likely to influence the adoption of targeted selective treatment strategies by sheep farmers in Western Australia.

The investigation aimed to assess factors affecting the uptake of novel targeted selective treatment (TST) strategies by sheep farmers in Western Australia where the most common nematode species present were Teladosagia circumcincta, Trichostrongylus spp. and Nematodirus spp. ("scour worms"). The study used a questionnaire format with questions concentrated on current worm control practices and farmers' current understanding and adoption of putative TST strategies. Participants represented a range of environments (derived from four farming regions) and sheep management situations, and it is therefore likely that the results of this investigation will apply in other locations where scour worms predominate. Sixty-five percent of participants were aware of the TST concept and 25% had implemented it in some form. The awareness of the TST approach was greatest where sheep farmers were concerned about anthelmintic resistance, where tools such as worm egg counts and faecal worm egg count resistance tests were employed, and where professional advisers were consulted regarding worm control. Respondents that sought advice chiefly from rural merchandise retailers were considerably less (0.1-0.6 times) likely to be aware of these management tools or to be aware of TST approaches. The findings indicated that the adoption of TST strategies will require greater use of professional advisers for worm control advice by sheep farmers, and that advisers are conversant with TST concepts.

[Soil-transmitted nematode infections and cognitive behavior in rural residents of Dezhou City in 2011].

OBJECTIVE: To understand the status of soil-transmitted nematode infections, as well as the awareness and healthy behavior on soil-transmitted nematodiasis in rural residents of Dezhou City. METHODS: Six villages were selected according to the stratified sampling method; the permanent resident population aged 3 years or above was determined as the investigation objects. The modified Kato-Katz technique was adopted to detect the eggs of Ascaris lumbricoides, hookworm and Trichuris trichiura in the feces of the residents, and the method of cellophane anal swab was used to detect the Enterobius vermicularis infection in children under 12 years old. More than 50 households in each investigated site were randomly selected to investigate the awareness status on nematodiasis prevention and treatment and the condition of healthy behavior formation. RESULTS: A total of 2 294 residents were detected by Kato-Katz methods, 11 of them were positive, and the total infection rate of soil-transmitted nematodes was 0.48%. Totally 260 children were detected and 40 were infected with E. vermicularis, and the infection rate was 15.38%. A total of 898 residents were investigated in the household survey and the awareness rate of nematodiasis prevention and treatment was 44.99%, the proportion of residents with healthy behavior was above 70%. CONCLUSIONS: The infection rate of soil-transmitted nematode is low in rural areas of Dezhou City, but the infection rate of E. vermicularis in children is higher. The condition of healthy behavior formation is satisfying, but the awareness rate of nematodiasis prevention and treatment of the residents is low. Therefore, the control measures as well as healthy education still should be strengthened.

Do intestinal nematodes affect productivity in adulthood?

Intestinal nematode infections have been associated with many physical and mental developmental insults. These include anaemia, wasting, stunting, cognitive impairment and lowered educational achievement, all of which have in turn been shown to interfere with productivity and wage-earning capacity in adults. Although there is no direct evidence for an effect of intestinal nematodes on productivity, circumstantial evidence suggests such an effect. Here, Helen Guyatt reviews the indirect evidence for an effect of intestinal nematodes on productivity in adults through current infection and associated morbidity, and on early ill-health in children, which might affect productivity later in life.

Parasite-induced learned taste aversion involving Nippostrongylus in rats.

After demonstrating that rats were capable of discriminating between the same diet treated with either flavour 1 or flavour 2 and that the 2 flavours of diet were equipreferred, an experiment was carried out to see whether learned taste aversion might play a role in the reduction of food intake that is commonly observed during the course of a parasitic infection. The results showed that rats, given a subcutaneous inoculation of approximately 6000 third-stage larvae of Nippostrongylus brasiliensis (Nematoda) while feeding on a diet containing flavour 2, strongly preferred to eat diet containing flavour 1 when given simultaneous choice conditions. Uninfected rats showed no preference and ate equal amounts of both flavoured diets. This effect is interpreted as the first experimental demonstration of learned taste aversion using a eukaryotic parasite as the inductive agent.

Parasitism and behavioral dominance among male mice.

Infestations by the nematode Heligmosomoides polygyrus can prevent adult male mice from becoming behaviorally dominant. The effect is dose-dependent and is more likely to influence the development of dominance than to disrupt existing dominance relationships. Doses capable of exerting this effect are not lethal and do not affect weight.