Effect of the organophosphorous insecticide, chlorpyrifos (Dursban), on growth, fecundity and mortality ofBiomphalaria alexandrinaand on the production ofSchistosoma mansonicercariae in the snail

Abstract

Exposure ofBiomphalaria alexandrinato sublethal concentrations (0·125, 0·25 and 0·05 ppm) of the organophosporous insecticide, chlorpyrifos (Dursban), induced a reduction in egg production and egg hatchability. Exposure ofSchistosoma mansonimiracidia to the insecticide (60 min, 0·05 ppm) prior to infection ofB. alexandrinadid not affect the subsequent production of cercariae. However, exposure ofS. mansoni—infected snails to the insecticide until day 55, from day 20 to day 62 and from day 35 to 62 following infection resulted in blockage of cercarial shedding. cercarial shedding commenced in some snails when the treatement stopped. Exposure to the insecticide in concentrations of 0·125 and 0·25 ppm during the first 20 days following infection did not affect the subsequent production of cercariae, but exposure to 0·5 ppm during the first 20 days affected markedly the production of cercariae due to a high snail mortality. The findings indicate that the cercaria is the target stage for the activity of chlorpyrifos on the intramolluscan larval development. It is suggested thatS. mansonicercarial production inB. alexandrinamay he a useful system for monitoring the effect of low concentrations of pesticides on the aquatic environment, and that the ability by chemical means to interrupt the cercarial production might be a useful tool in further analyses of important aspects of the snail/parasite relationship.

Computational analysis of movement behaviors of medaka (Oryzias latipes) after the treatments of copper by using fractal dimension and artificial neural networks

“…Dutta et al [2] suggested that a behavioral bioassay would be more sensitive than other types of testing methods. A numerous accounts of behavioral research on effects of toxic chemicals at low concentrations have been reported in various taxa, including crustaceans [3,4], snails [5], fish [6] and insects [7,8]. Recently Oshima et al [9] observed suppression of sexual behavior in male medaka exposed to estradiol.…”

Characterizing response behavior of medaka (Oryzias latipes) under chemical stress based on self-organizing map and filtering by integration

“…no escape) and are exposed to a constant level of chemical stress, every organism has its own ability to adapt to the environmental stress by intrinsic modification, which might induce stepwise BRs including behavior stimulation, acclimation, adjustment and so on (Sun et al, 1993;Zhang et al, 2012). By far, BR of various taxa, including crustaceans (Billoir et al, 2007;Kim et al, 2006;Roast et al, 2000), snails (Coffin et al, 2008;Ibrahim et al, 1992), insects (Chon et al, 1998;Ji et al, 2007), and fish (Gray et al, 1999;Liu et al, 2011;Moore and Waring, 1996), has been reported to be sensitive to sublethal exposures to numerous chemical pollutants, which have drawn attention as a means of developing a biomonitoring tool for detecting toxic chemicals in the environment. In fact, as an efficient tool for biomonitoring in aquatic ecosystems, the automatic detection of response behaviors has received considerable attention since 1980s (Lemly and Smith, 1986).…”

Persistence Parameter: a Reliable Measurement for Behavioral Responses of Medaka (Oryzias latipes) to Environmental Stress

“…Meanwhile, behavioral response has been suitable in addressing toxicological impact assessment in all of the test endpoints [1,8,14,18,32,35]. By far, behavioral response of various taxa, including crustaceans [41,25,7], snails [23,13], insects [11,24], and fish [31,16,30], has been reported to be sensitive to sublethal exposures to various chemical pollutants. Based on the concentration-response-time analysis [43,19], the assessment of toxicity of chemicals by behavioral eco-toxicology has successfully been applied in Daphnia magna [3].…”