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 Table of Contents  
Year : 2015  |  Volume : 8  |  Issue : 2  |  Page : 123-126

Soil contamination with Cryptosporidium spp. in the west of Iran

1 Department of Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
2 Skin Diseases and Leishmaniasis Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
3 Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran

Date of Submission20-Sep-2015
Date of Acceptance24-Nov-2015
Date of Web Publication27-Jan-2016

Correspondence Address:
Mohammad A Mohaghegh
PhD., Department of Parasitology and Mycology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1687-7942.175010

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Cryptosporidium spp. is a coccidian protozoan parasite that causes gastrointestinal disorders in human and animals. Several studies have demonstrated that the soil of public parks and schools presents an important source of infection which has a significant impact on public health. Children are the main group affected by accidentally ingesting contaminated soil.
Aim of the work
The aim of this study was to detect the presence of Cryptosporidium spp. oocysts in soil collected from primary schools and parks in Kermanshah city, west of Iran.
Materials and methods
The survey was conducted from August to December 2014 in Kermanshah city. Altogether 192 randomly selected soil samples were collected from 24 parks and 24 primary schools in six regions. The samples were screened for Cryptosporidium spp. oocysts using Sheather's flotation method and modified Ziehl-Neelsen staining.
Out of 192 samples, 49 (25.5%) were found to contain Cryptosporidium spp. oocysts. Data analysis using χ2 -test revealed that there was no significance among parks and primary schools in terms of the contamination rate (P = 0.24). Furthermore, there was no significant difference between the contamination rate and different regions of Kermanshah (P = 0.36). Regions 3 and 4 had the highest contamination rate (34.4%) and the lowest was for region 6 (15.6%).
Considering human infection with different Cryptosporidium spp. and the increase in numbers of immunocompromised patients, high contamination of soil with this parasite in Kermanshah stands as a serious problem. Consequently, health promotions, public education, improving sanitation conditions, especially for the underprivileged, are the keys to success in preventing the spread of Cryptosporidium spp. infection. In this regard, findings of this study can be used as a basis for preventive programs and development strategies targeting groups for the prevention of greater risk of cryptosporidiosis.

Keywords: contamination, Cryptosporidium spp., Iran, parks, primary schools

How to cite this article:
Ghomashlooyan M, Vafaei MR, Kalani H, Mirzaei F, Azami M, Jafari R, Falahati M, Safa AH, Mohaghegh MA. Soil contamination with Cryptosporidium spp. in the west of Iran. Parasitol United J 2015;8:123-6

How to cite this URL:
Ghomashlooyan M, Vafaei MR, Kalani H, Mirzaei F, Azami M, Jafari R, Falahati M, Safa AH, Mohaghegh MA. Soil contamination with Cryptosporidium spp. in the west of Iran. Parasitol United J [serial online] 2015 [cited 2021 May 12];8:123-6. Available from: http://www.new.puj.eg.net/text.asp?2015/8/2/123/175010

  Introduction Top

Cryptosporidium spp. is a coccidian protozoan parasite that causes gastrointestinal disorders in human and animals. The infection is more common in children as a self-limiting disorder, but in immunocompromised patients, it can be considered as a serious health risk [1],[2] . This parasite is considered as one of the main factors in the outbreak of diarrhea and vomiting in developing countries [3] . Cryptosporidiosis is one of the most important water-borne diseases, and one of its clinical manifestations is self-limiting watery diarrhea that persists from a few days to a lot longer [4] . There are several species that are morphologically indistinguishable from each other [5] . Cryptosporidiosis is very common among mammals, some of which are closely related to humans. Cryptosporidium hominis, Cryptosporidium parvum, Cryptosporidium canis, Cryptosporidium meleagridis, Cryptosporidium wrairi, Cryptosporidium felis, Cryptosporidium suis, Cryptosporidium andersoni, and Cryptosporidium muris are species capable of infecting humans [2],[6],[7],[8],[9] , and the first two species are commonly reported to infect humans [10] . Several studies showed that there is an indirect relationship between the duration of cryptosporidiosis and CD4 + cell count. Furthermore, ectopic forms of this disease have been reported in HIV/AIDS [11],[12] and non-AIDS immunocompromised patients, including hemodialysis, diabetic, organ transplant, and cancer patients [13],[14],[15] .

Soil is an important source for diseases transmission, identified as soil-transmitted diseases. A large number of pathogens are able to bind to soil particles and spread in the environment [16] . Therefore, soil contamination with pathogens in an area is of public health importance. Accordingly, in recent years many studies have been conducted to determine the prevalence of some parasitic agents in the soil, especially in areas where people live [16],[17],[18] . Epidemiological studies in Korea [19] , Mexico [20] , Spain [21] , and Brazil [22] showed that the prevalence of Cryptosporidium spp. oocysts in the soil was 32.4,% 52%, 9%, and 7.4%, respectively. In a recent study done in Isfahan, Iran, oocysts were observed in 31 out of 140 soil samples (22.14%) [23] . One of the major reasons for the spread of soil-transmitted parasitic diseases is the use of manure on farmlands, parks and green space. Consequently, these areas can act as an important source of Cryptosporidium spp. oocysts infection of people. Therefore, the aim of this study was to determine the occurrence of Cryptosporidium spp. oocysts in the soil collected from primary schools and parks in Kermanshah city, west of Iran.

  Materials and methods Top

Type of study:

This study was designed as a cross-sectional study.

Study area

Kermanshah city is located in the center of Kermanshah province, west of Iran. According to the 2011 census, its population is 851,405. The city has a mountainous climate and is surrounded by the Zagros Mountains, being cold and snowy in winter and rainy in spring and autumn. This city is a major center for agriculture in the west of Iran, producing grain, rice, vegetables, fruits, and oilseeds. Kermanshah is divided into six regions, including center (regions 1, 2), east (region 3), south (region 4), north (region 5) and west (region 6).

Sample collection

This survey was conducted from August to December 2014. A total of 192 soil samples were collected from 24 public parks and 24 primary schools, four samples from each region of Kermanshah city. The samples were collected from four parks and four primary schools. Accordingly, about 200 g of soil was gathered from an approximate depth of 2-5 cm. The samples were placed in plastic containers, labeled with a number and dried in air.

Sample preparation

Flotation technique was used for Cryptosporidium spp. oocyst isolation. The dried soils were passed through a sieve and then 2 g of each soil sample was poured into a centrifuge tube. Afterwards, 10 ml Tween 80 solution with a concentration of 0.05% was added to each tube and mixed well with the soil. The mixture was centrifuged at 1500 rpm for 5 min. The supernatant was discarded and then the sucrose solution (1.2 g/ml) was added to 1 cm from the top of the tubes. The tubes were centrifuged again and then gently filled to the top with sucrose solution. Finally, a separate glass slide was placed on the tubes for 30 min [24] .

Cold modified Ziehl-Neelsen staining method

A separate smear was prepared from each sample and allowed to air dry. The smears were fixed by absolute methanol and then stained using cold modified Ziehl-Neelsen staining method. Initially, the smears were stained in carbol Fuchsin solution for 15 min, rinsed, and then decolorized with hydrochloric acid (1%) for 30 s. The smears were rinsed in tap water again and restained with 0.25% methylene blue for 30 s as a background color and then rinsed. Finally the air dried slides were examined for the presence of Cryptosporidium spp. oocysts using ×1000 of magnification [24] .

  Results Top

Out of 192 soil samples, 49 (25.5%) were found to contain Cryptosporidium spp. oocysts ([Table 1]). The contamination rate in public parks and primary schools was 21.9 and 29.2%, respectively. Data analysis using χ2 -test revealed that there was no significant occurrence of oocysts contamination between parks and primary schools (χ2 = 1.34, P = 0.24). Furthermore, there was no significant difference between the contamination rate and different regions of Kermanshah (χ2 = 5.39, P = 0.36). Regions 3 and 4 were found to be highly contaminated (34.4%) compared with the other examined sites and the lowest rate of contamination (15.6%) was observed in region 6.
Table 1 Frequency of the soil samples according to regions and number of positive samples in parks and primary schools

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  Discussion Top

Cryptosporidiosis in developing countries is a major cause of acute and persistent diarrhea, especially in immunocompromised individuals such as HIV/AIDS patients, malnourished children and elderly people [25] . It deserves mentioning that geophagia may occur in malnourished children, increasing the risk of acquiring the infection from soil. Many studies have also shown an association between socioeconomic status and prevalence of parasitic infections as an important factor in Iran [26],[27],[28],[29] . Oocysts of Cryptosporidium spp. are resistant to environmental conditions, and can even survive at −10°C [30] . This situation brings about an ideal condition for the transmission of this parasite. Therefore, the above-mentioned disorders may increase the chance of infection with Cryptosporidium spp. that may occur in pregnant women as well [31] .

In this study, we used the flotation procedure for isolation of Cryptosporidium spp. oocysts from soil. This method does not require sophisticated equipment and is easy to perform and also can be utilized in each laboratory. In addition, with this method, only infective oocysts are able to float above sucrose solution [32] . Accordingly, it is a useful method for estimating the abundance of active oocysts, infective to humans.

The results of the present study showed that the soils obtained from Kermanshah parks and primary schools could be a potential source for cryptosporidiosis for residents in this area. Because the ingestion of 30 Cryptosporidium spp. oocysts can cause clinical disease [33] , so it can be hypothesized that the possibility of infection in Kermanshah could be high. The prevalence of Cryptosporidium spp. infection in patients with AIDS has been reported as 26.7% in Kermanshah [34] , but the source of infection was not known and soil transmission is possible.

In the present study, high contamination of soil (29.2%) was observed in primary schools. In a previous study Cryptosporidium spp. were detected in the feces of 21.4% of children younger than 15 years of age with diarrhea in Iran [35] . The findings of the mentioned study show that the infection is highly prevalent in Iran. Also our results show a high contamination of soil with the parasite that may present a source of some proportion for infections in Iran. Researches for the prevalence of Cryptosporidium spp. oocysts in soil have rarely been performed and there were only two reports of soil contamination rate from Tehran (10%) and Isfahan (22.1%) [23],[36] .

In another study on soil in southeast of New York state, where cattle are the main agents of soil contamination, oocysts of Cryptosporidium spp. were detected in 17% of samples [37] . Runoffs from contaminated soil and sewages are of the most important sources responsible for water contamination [36] . Mac Kenzie et al. [38] reported the massive outbreak of cryptosporidiosis in Milwaukee, Wisconsin, USA. The examination of contamination of rivers in Paris and its surrounding area showed 45.7% pollution with Cryptosporidium spp. oocysts. For this reason the role of soil in this contamination cannot be ignored [36] .

In conclusion results of this study suggested that the prevalence of Cryptosporidium spp. parasite in the soil has implications for the spread of human disease in these areas. As Cryptosporidium spp. infection can be mediated through soil, it is necessary to reduce contamination of this organism in view of public health. This study can be used as a basis for preventive programs, especially for at risk groups.


We would like to thank all the people who cooperated in this study.

Author contribution: Concept and design of study: MA Mohaghegh, M Azami and H Kalani; acquisition of data: MR Vafaei, AH Safa and M Falahati; analysis and interpretation of data: M Ghomashlooyan, F Mirzaei and R Jafari; drafting the article: MA Mohaghegh, M Ghomashlooyan and MR Vafaei; revising the first draft of the paper: M Azami, H Kalani, AH Safa, M Falahati, F Mirzaei and R Jafari; final approval of the version to be published: all authors.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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