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The helminth communities of wild murid rodents were investigated in Luang Prabang and Champasak province, Lao PDR. Thirteen species of rodents (404 individuals) were infected by 19 species of parasites (2 trematode, 3 cestode, 14 nematode species). Four of the recorded helminth species (Echinostoma malayanum, Raillietina sp., Hymenolepis diminuta and H. nana) are known to cause potential zoonotic helminthiases of medical importance in the South-East Asian region. Individual helminth infection was significantly higher in the wet season. Habitat significantly influenced individual helminth species richness and individual helminth abudance, with a decrease of individual helminth species richness and individual helminth abundance from forest habitat to agricultural and human settlement habitats. The reduction of helminth diversity and abundance is discussed in relation to the ongoing increase of human influence on habitats in Lao PDR.

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The effects of estradiol-17β(E2) on embryos and larvae of the giant freshwater prawn, Macrobrachium rosenbergii (De Man, 1879), were investigated. Embryos, obtained from brooding females within one day of spawning, were exposed to 1, 10, or 50 µg/ml estradiol-17β for 2 days. No significant differences in growth or in survival rate with those of controls were found. However, those exposed to 10 µg/ml E2 showed an increase in hatching rate, in the number of primordial germ cells (PGCs), and in the rate of incorporation of the PGCs into the developing gonads. Similarly, newly hatched larvae exposed to 1, 5, or 10 µg/ml E2 for 2 days did not show significant differences in growth, survival, or developmental rate from those of the controls. However, larvae exposed to 5 or 10 µg/ml E2 showed slightly more developed gonads. RÉSUMÉLes effets de l'oestradiol-17β(E2) sur les embryons et les larves de la crevette géante d'eau douce, Macrobrachium rosenbergii (De Man, 1879), ont été recherchés. Les embryons, obtenus à partir des femelles ovigères, au premier jour de ponte, ont été exposés à 1, 10, ou 50 µg/ml d'oestradiol-17β pendant deux jours. Aucune différence significative de la croissance ou du taux de survie, n'a été observée par comparaison aux embryons témoins. Cependant, ceux exposés à 10 µg/ml E2 ont montré une augmentation du taux d'éclosion, du nombre de cellules germinales primaires (PGCs), et du taux d'incorporation des PGCs dans les gonades en développement. De même, les larves nouvellement écloses exposées à 1, 5, ou 10 µg/ml E2 pendant deux jours n'ont pas montré de différences significatives dans la croissance, la survie ou le taux de développement par rapport aux témoins. Cependant, les larves exposées à 5 ou 10 µg/ml E2 présentaient des gonades légèrement plus développées.