Third stage larvae (L3) from Angiostrongylus costaricensis were incubated in water at room temperature and at 5 degrees C and their mobility was assessed daily for 17 days. Viability was associated with the mobility and position of the L3, and it was confirmed by inoculation per os in albino mice. The number of actively moving L3 sharply decreased within 3 to 4 days, but there were some infecti...

Successful transmission of macroparasites is dependent on exposure of susceptible hosts to free-living infective stages. When these hosts are herbivores that feed mostly on a single food plant then natural selection should favour those infective larvae that selectively ascend this main food plant. Red grouse feed predominantly on heather, Calluna vulgaris, so we predict that the infective larva...

This study was conducted to determine the effect of temperature and moisture stress on exsheathment process and infectivity of the infective larvae of the parasitic nematode Haemonchus contortus. Laboratory conditions were used in which infective (L3) of H. contortus were either subjected to gradually increasing temperatures, decreasing moisture or both. Post stress viability and exsheatment of...

Contact with the soil, fomites or hands contaminated with the animals’ feces favors accidental human infection either through ingestion of Toxocara canis embryonic eggs, resulting in Visceral Larva Migrans (VLM) syndrome (Coelho et al., 2001), or through percutaneous penetration of Ancylostoma caninum and Ancylostoma braziliense infective larvae, causing Cutaneous Larva Migrans (CLM) Syndrome (...

Ganaspis xanthopoda is a solitary larval parasitoid wasp of the fruit fly Drosophila melanogaster. The life cycle of Ganaspis xanthopoda in the wild-type and developmental mutant ecdysoneless strains of Drosophila melanogaster is described. The female infects a second-instar host larva. The parasitoid embryo hatches into a mobile first-instar (L1) larva. The L1 parasitoid has fleshy appendages ...

In vitro chemotactic responses of infective third-stage larvae (L3) of Brugia pahangi to NaCl, Na2HPO4, KCl, K2HPO4, MgCl2 and CaCl2 were assessed. Compared to deionized water as a control, 200 mm NaCl and 100 mm Na2HPO4 significantly attracted L3 (P < 0.01 and P < 0.01), whereas L3 were likely to avoid 200 mm KCl and 100 mm K2HPO4 (P < 0.05 and P < 0.05). L3 showed no significant tendency to a...

VANWYK, J.A. 1999. A comparison of the infectivity of cryopreserved versus unfrozen infective larvae of Haemonchus contortus, Trichostrongylus colubriformis and Trichostrongylus axei: Results of the Onderstepoort Veterinary Institute from 1977 to the present. Onderstepoort Journal of Veterinary Research , 66:285289 The infectivity for sheep of cryopreserved infective larvae (L3) of various stra...

The ingested microfilariae develop into the infective third-stage larvae (L3) after several molts. These L3 migrate to the mosquito head and mouthparts where they are deposited in hemolymph onto mammalian skin during subsequent blood meals. After the deposited L3 enter the host through the mosquito bite wound, they molt to fourth-stage larvae (L4). The L4 then migrate through the tissues toward...

BACKGROUND Existing molecular assays for filarial parasite DNA in mosquitoes cannot distinguish between infected mosquitoes that contain any stage of the parasite and infective mosquitoes that harbor third stage larvae (L3) capable of establishing new infections in humans. We now report development of a molecular L3-detection assay for Brugia malayi in vectors based on RT-PCR detection of an L3...

As the effectiveness of current anthelmintic drenches is being reduced by the emergence of drench resistance and significant production losses may still occur as a result of continuing larval challenge, strategies for nematode control should focus on preventing the build-up of infective larvae on pasture rather than treating the infection. This paper reports the effects of condensed tannins (CT...