ABSTRACT
The free-living infective juveniles of the entomopathogenic nematodes are non-feeding, so the stored energy reserves in these juveniles are of great importance. The relationship between the energy reserves and the efficacy of the entomopathogenic nematodes of genera Heterorhabditis and Steinernema was studied. New progenies of S. riobrave and H. bacteriophora (ISK-2 strains), were obtained using the continuous culturing method of nematode juveniles (IJs), for the several cycles under the optimum condition of the temperature (25 degrees C) and nematode density (20 IJs/ larva), inside the host Galleria mellonella. Thus, the nematode efficacy was maximized with a high conservation of energy reserves. The results showed that there was an increase in the penetration rate and the virulence through the new progenies of S. riobrave and H. bacteriophora than in the original progenies, with an increase in the energy reserves.
Subject(s)
Conservation of Energy Resources , Lepidoptera/parasitology , Rhabditida/physiology , Rhabditoidea/physiology , Animals , Host-Parasite Interactions , Rhabditida/pathogenicity , Rhabditida Infections , Rhabditoidea/pathogenicity , Survival RateABSTRACT
In mixed infection with Schistosoma mansoni and S. haematobium in hamsters, either simultaneously or after the full maturation of an initial infection with either schistosome species, a high level of acquired resistance was observed. The degree of immunity was magnified by the significant reduction in the number of eggs per gram tissue and hatchability of mature eggs. Some disturbance was also observed in the oogram pattern.
Subject(s)
Schistosoma haematobium/growth & development , Schistosoma mansoni/growth & development , Schistosomiasis haematobia/parasitology , Schistosomiasis mansoni/parasitology , Animals , Cricetinae , Feces/parasitology , Parasite Egg Count , Schistosoma haematobium/isolation & purification , Schistosoma mansoni/isolation & purification , Schistosomiasis haematobia/complications , Schistosomiasis mansoni/complicationsABSTRACT
Hamsters infected with Schistosoma mansoni and S. haematobium either simultaneously or after maturation of an initial infection with either schistosome species were examined to estimate the biological and morphological changes under mixed infection conditions. The results indicate a high level of acquired resistance. The degree of immunity was evidenced by the significant reduction in the worm load as well as in the size of mature worms. Some disturbance was observed in the worm distribution. The results are important for epidemiological and immunological uses, as well as in development of a vaccine from one species that might be effective against both species.
