Helminthologia最新文献

The brown marmorated stink bug (Halyomorpha halys), a native of Asia, has become an invasive pest in North America and Europe. Given the severity of H. halys and the need for better and environmentally-friendly control methods for this pest, we evaluated the virulence four entomopathogenic nematode species (Heterorhabditis indica, Oscheius myriophilus, Steinernema eapokense and Steinernema pakistanense) that occur naturally in soils in southern Việt Nam and compared them with that of a commercially available strain of S. carpocapsae. We report for the first time the pathogenicity of Oscheius myriophilus towards BMSB. The commercial strain of S. carpocapsae was most virulent against BMSB. However, the strain of S. pakistanense isolated from soil in southern Việt Nam has potential for the biological control of this pest. To achieve this potential, further work is needed including evaluation in the field and with the formulation of the nematode inoculum.

The search for hitherto undiscovered larvae of Anisakis sp. from marine habitat in the Indian sub-continent yielded A. typica (Dujardin) larvae hitherto unconfirmed. The present study is the maiden attempt to report 3^rd stage larvae of A. typica from the reef-associated Sillago sihama in Arabian Sea off the coast of Goa, which has been identified recently as reef-populated area within the maritime boundary of India. The morphometry of 3^rd stage larvae has been presented with a record of molecular characterization. In the context of current study, the natural prevalence of A. typica larvae in marine piscine hosts of Arabian Sea in India was 6.84 % and of co-occurring Rotundocollarette capoori (Yadav, Kapoor and Malhotra) in the same fish was 13.65 %. The roundworms were confirmed to be A. typica by application of the molecular and genetic characterization based on ITS1, ITS2 and 18S rDNA sequence analysis. The infestation of reef-associated fishes in this study by anisakid worms study provided an opportunity to explore mechanism of ecological associations of coral reefs with parasitization in future.

The recent publication entitled "Possible zoonotic implications of the discovery of the advanced third stage larva of Gnathostoma turgidum (Spirurida: Gnathostomatidae) in a Mexican fish species" by Mosqueda-Cabrera et al., appeared in Helminthologia, 2023; 60(1): 112-116. was extremely interesting and informative showing potential zoonotic natue of G. turgidum. However, discovery of only one larva from one out of 17 fish rather indicate that this fish is an accidental host of G. turgidum. Whether this and other fish act as the second intermediate host in the life cycle of G. turgidum requires more field survey using both compression and digestion methods. Also, many biological events of G. turgidum such as intrahepatic maturation in the final hosts and the seasonal changes with self cure are remained unsolved. More extensive survey on intermediate and paratenic hosts for G. turgidum and biological research on unique features of G. turgidum is necessary.

Dengue is currently the most important arbovirosis in the world, affecting over 120 countries in both tropical and sub-tropical areas, with 2500 million people at risk. Due to global warming, it is expected that Aedes aegypti will be able to survive at higher latitudes, increasing the number of people at risk. Therefore, it is crucial to develop control strategies for the mosquito to prevent its environmental impact. The objective of this paper was to determine the concentration of entomopathogenic nematode (EPN) Steinernema carpocapsae that produces the highest percentage mortality of Ae. aegypti larvae under normal environmental conditions in Yucatán (6.9 - 8.7 mg/l; temperature 25.9 - 31.5°C; pH 7.20 - 8.10). The S. carpocapsae mode of action consists of Xenorhabdus nematophila bacterial release in the haemocele insect, which produces septicaemia and consequently kills the mosquito larvae 24 - 48 h after intake. As for the methodology, a commercial EPN strain was used for experimental infection. The experimental design was a 70-h static bioassay that exposed 10 mosquito larvae per experimental unit (400-ml flask and five replicates per treatment) to four nematode concentrations (1250, 2500, 3125 and 3750 nematodes per ml) plus controls. The best treatment was with 1250 nematodes/ml, which caused 54 % mortality with respect to controls after 70 h (one-way ANOVA; F _{5.72, 0.05}; p < 0.04). We concluded that S. carpocapsae is a promising biological control tool for killing Ae. aegypti larvae at an experimental level. However, it is still necessary to determine its performance at higher volume scales in real-life conditions.