Parasitic contamination of the Astrakhan soil with helminth eggs and larvae

Abstract

The purpose of the study. To analyze the parasitic contamination of the Astrakhan soil with eggs and larvae of helminths. Materials and methods. A total of 438 soil samples were selected and examined during the analyzed period, of which 21.2 % (n=93) did not meet the indicators of parasitic safety. The following helminth eggs and larvae were found in these samples: dead Strongyloides stercoralis larvae — 77.4 % (n=72), Toxocara canis eggs — 10.8 % (n=10) and Askaris lumbricoides — 11.8 % (n=11). The results of the study. The largest number of soil samples selected for the study for the presence of eggs and larvae of helminths and cysts of pathogenic intestinal protozoa was investigated among the playgrounds of the city of Astrakhan and amounted to 71.9 % (n=315) of all studied soil samples for the analyzed period. The number of positive findings in these soil samples was 14.9 % (n=47). In this case, dead Strongyloides stercoralis larvae were found in 97.9 % (n=46) of samples and unfertilized Askaris lumbricoides eggs — in 2.1 % (n=1). In addition to the soil from playgrounds, we selected and examined the soil from the territories of parks and squares. Thus, during the analyzed period, 13.2 % of samples were examined (n=58), of which 36.2 % (n=21) did not meet hygienic standards as dead larvae of Strongyloides stercoralis — 53.4 % (n=11) and Toxocara canis eggs — 46.6 % (n=10) were found in these samples. Also, we examined the soil from the territories of urban beaches — 8.0 % (n=35), of which 28.6 % (n=10) did not correspond to the norm. In all cases, dead Strongyloides stercoralis larvae were found in the samples. In addition to playgrounds, beaches, and recreation areas for citizens and guests of the city, we conducted a study of soil taken from the territories of higher educational institutions, of which half of the samples — 50.0 % (n=15) did not meet the norm for parasitological indicators. Unfertilized Askaris lumbricoides eggs (66.7 %) and dead Strongyloides stercoralis larvae (33.3 %) were found in these soil samples (n=5). Conclusions: the largest number of unsatisfactory soil samples was noted in 2018, when dead Strongyloides stercoralis larvae, Toxocara canis eggs and unfertilized Askaris lumbricoides eggs were found; the presence of Toxocara canis eggs and dead Strongyloides stercoralis larvae in the soil indicates contamination of this object with the feces of infected animals; the presence of unfertilized Askaris lumbricoides eggs in soil samples taken from playgrounds and beaches of the Astrakhan city shows the contamination of these objects with the feces of infected people; the presence of unfertilized eggs of Askaris lumbricoides in soil samples taken from the territory of higher educational institutions and parks in Astrakhan indicates accidents on the sewer network.