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Experiments were undertaken to investigate the factors which influence the transmission dynamics of Gyrodactylus bullatarudis within populations of laboratory guppies. The parasites possess a number of biological attributes which are almost unique amongst helminth parasites of vertebrates. These include the ability to reproduce viviparously and directly on(More)
BACKGROUND The soil-transmitted helminths (STH) Ascaris lumbricoides and Trichuris trichiura are gastrointestinal parasites causing many disabilities to humans, particularly children. The benzimidazole (BZ) drugs, albendazole (ALB) and mebendazole (MBZ), are commonly used for mass treatment for STH. Unfortunately, there is concern that increased use of(More)
Studies of phenotypic variation in nature often consider only a single potential selective agent. In such cases, it remains an open question as to whether variation attributed to that single measured agent might be influenced by some other unmeasured agent. Previous research has shown that phenotypic variation in the Trinidadian guppy (Poecilia reticulata)(More)
Nutritionists have long understood that intestinal nematode parasites have deleterious effects on host nutritional status, but only recently has the importance of malnutrition as a predisposing factor to intestinal nematodes been recognized. Here we review experimental and field studies on the effects of protein, energy, zinc, vitamin A, and iron(More)
Protein malnutrition may increase susceptibility to gastrointestinal parasitic infections, possibly as a result of impaired intestinal and/or systemic T helper 2 (Th2) effector responses induced by down-regulation of Th2 cytokines and/or up-regulation of Th1 cytokines. To test this hypothesis, female BALB/c mice (n = 18/diet) were fed a control (24%),(More)
Changes in the variance to mean ratio and the parameter k of the negative binomial distribution were used to study temporal changes in the degree of aggregation of the monogenean parasite, Gyrodactylus turnbulli in free-running laboratory populations of the guppy, Poecilia reticulata. The parasite undergoes recurrent epidemic cycles in the host population(More)
This study examined whether the impaired immune responses in zinc deficient- and/or energy-restricted mice exposed to a challenge infection of Heligmosomoides polygyrus might be associated with reduced numbers of spleen cells, altered proportions of spleen cell subpopulations and/or altered function of the T cells or antigen-presenting cells (APC). Female(More)
Although boron (B) is an essential trace mineral, any interactions that it may have with gastrointestinal (GI) nematode infections are unknown. This study explored whether low dietary B would: 1) alter survival or reproduction of Heligmosomoides bakeri (Nematoda); 2) modify the resulting cytokine response to this parasitic infection; or 3) influence liver(More)
Benzimidazole anthelmintics are the most common chemotherapeutic agents used to remove intestinal helminths from farm animals. The development of drug resistance within helminth populations is wide-spread and can render these drugs essentially useless. The mechanism of benzimidazole resistance appears to be common to many species ranging from fungi to(More)
This study determined whether the timing of re-feeding of protein-deficient mice restored functional protection against the gastrointestinal nematode, Heligmosomoides bakeri. Balb/c mice were fed a 3% protein-deficient (PD) diet and then transferred to 24% protein-sufficient (PS) diet either on the day of primary infection, 10 days after the primary(More)