Geohelminths distribution as affected by soil properties, physicochemical factors and climate in Sharkyia governorate Egypt

Abstract

Soil-transmitted helminths are mainly a group of parasitic nematodes causing human infection through contact with parasite eggs or larvae; they survive in the warm and moist soil of the tropical and subtropical countries. This study was carried out in Sharkyia governorate from October, 2011 to October, 2013, to correlate between the prevalence and distribution of these parasites in the soil and the physicochemical factors affecting the examined samples of the soil. One hundred and twenty samples of different types of soil (clay, silt, sand) from different localities were collected and examined. Diagnosis of geohelminths was confirmed by the recovery of their eggs and larvae with other protozoa by different parasitological methods. The modified baermann method was found to be more efficient in detection of geohelminths larvae than charcoal culture method. Among the examined sites geohelminths were much more numerous in the soil of rural areas especially in the spring and summer seasons, while the contamination of canal banks by geohelminths was the worst (80 %). An insignificant correlation was reported between the soil texture and the number of positive samples in the examined areas while the relationship was directly proportional among (moisture, PH, organic). It appeared that the most common geohelminthic stage was Toxocara spp. eggs besides other types of protozoa especially Balantidium coli cysts. This suggests that factors other than soil texture are important in the prevalence of geohelminths in the soil e.g. temperature, moisture, PH and organic matter. So, to change some of these factors in a trial to control geoparasites transmission but with keeping the environment should be tried. These results also open the way to further studies to highlight the mutual affection between inhabitants of these sites and the prevalence of these geoparasites.

The relation between the prevalence of soil transmitted parasites in the soil and among school children in Zagazig district, Sharkyia Governorate, Egypt

“…In Egypt Khalil et al (1978) examined soil samples collected from different governorates and they reported the following rates of Toxocara contamination: 12.5, 11.5, 10 and 7.5 % in Giza, Cairo, Dakahlia and Qalyoubia respectively. Also, Etewa et al (2014) reported that, Toxocara spp. Eggs were the most widely distributed geo parasites in the soil of Sharkyia governorate.…”

Socio-Medical Studies of Individuals Self-Treating with Helminths Suggest That Most Clinical Trials Assessing Helminth Therapy May Be Designed to Fail

“…After passing through the pig gut at pH 6.1-6.6, TSO is deposited in soil (39,40). Geohelminths can survive in both slightly acidic and alkaline soils, with studies reporting presence of helminths between pH 5.21 -9.9 (41)(42)(43). Ingestion in the pig occurs between approximately pH 6.7 (44), and acidity increases as the TSO reaches the pig's anterior stomach at pH 4.4 and then the posterior stomach at pH 2.6 (40,45,46).…”

Prospects for elimination of soil-transmitted helminths

“…However, the evidence is mixed regarding the influence of WASH resources on STH prevalence and infection intensity [ 43 & , 44 & , 45 , 46 && , 47 , 48 ]. The impact of WASH is influenced by the specific intervention(s) used, the quality of the intervention, consistent WASH usage, and other individual-level behaviors, as well as contributors to the environmental reservoir such as WASH usage and behaviors of other members of the community,[ 44 & ] agricultural activities [ 49 , 50 ], and environmental factors such as precipitation and soil composition [ 43 & , 51 , 52 ]. Successful WASH interventions are not only challenging to systematically measure but also costly to implement relative to MDA, so are rarely provided at sufficient scale; universal access remains a distant target [ 40 , 53 ].…”