An Investigation of Parasitic Protozoa in Drinking Water in Samarra, Iraq

Document Type : Original Articles


1 College of Applied Science, University of Samarra, Samarra, Iraq

2 Department of Applied Chemistry, College of Applied Science, University of Samarra, Samarra, Iraq

3 Department of Pathological Analysis, College of Applied Science, University of Samarra, Samarra, Iraq


Protozoan parasites are very important in drinking water production systems because their cystic forms are stable in the environment and resistant to conventional disinfection methods. The present study aimed to investigate protozoan parasites in the drinking water of different places in Samarra, Iraq. To this end, 100 samples of tap drinking water were collected from 10 places in Samarra, Iraq (i.e., Al-Sekek, Al-Kadesia, Alzeraa, Al-Shuhdaa, Al-Muthana, Al-Shorta, Al-Mamal, Al-Khedraa, Al-Efraz, and Al-Jubereaa), from the beginning of December to the end of February. After sample collection, water samples were examined to detect oocysts or cysts of protozoan parasites by using Direct wet smear, Lugol’s iodine, and Modified Ziehle Nelseen stain methods. The results indicate that 80% of the samples under investigation were infected with protozoan parasites, and the ratio of diagnostic parasites in the samples under investigation was determined at 36% with Entamoeba histolytica, 23% with Giardia lamblia, and 21% with Cryptosporidium parvum. The findings reveal the presence of protozoan parasites in the drinking water of the area under study and specify the need for a rapid improvement of the monitoring systems for the treatment of drinking water to control diseases caused by these pathogens, as well as to identify the sources of contamination.


Main Subjects

1. Introduction

Due to the transmission of pathogens, such as bacteria and parasites, through drinking water, the study of water hygiene is very important in controlling and preventing diseases. Waterborne or water-washed parasitic diseases have caused epidemic and endemic diseases in both developed and developing countries ( 1 ). The water-borne protozoan parasites in humans include Toxoplasma gondii, Entamoeba histolytica, Cyclospora cayetanensis, Isospora belli, Blastocystis hominis, Balantidium coli, Acanthamoeba species (spp.), and Naegleria spp. ( 1 , 2 ). Samarra is an Iraqi archaeological city, which is located in the north of Baghdad, the capital of Iraq (120Km), and is characterized by its rising population density ( 3 ) (Figure 1).

Figure 1. Geographic location of Samarra, Iraq

The main source of drinking water in Samarra, Iraq, is the Tigris river near the city, which is also used with groundwater in industry, as well as agriculture, and other purposes in the city ( 3 - 5 ). Since the quality of water is of significant importance for humans, animals, and plants, any chemical, physical, and biological changes in water properties may affect the living organisms and make water unsuitable or polluted ( 6 ). Many researchers have investigated the chemical, physical, and biological properties of drinking water in Samarra, Iraq. Dheyab ( 7 ) found that the concentration of dissolved oxygen was 4.75 ppm (at 23˚C), chlorine was 2.97 ppm (more than the normal limit), electrical conductivity was 0.3 cm/m (within the normal limit), total soluble salt was 201 ppm (within the normal limit), turbidity was 2.26 Nephelometric Turbidity Unit (more than the normal limit), and pH was 7.99 (more than the normal limit). In another study, Ibrahim, Al-Tawash ( 8 ) indicate that water in Samarra is not drinkable, according to the Water Quality Index, and also it contains high concentrations of heavy metals (more than the standard limit), such as Cd, Se, Fe, Li, Pb, Mn, Ni, Hg, Cr, Be, As, V, Al, and uranium. Moreover, it was found that the drinking water in Samarra, Iraq, was also contaminated with microorganisms, including Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa ( 9 ), and Cryptosporidium parvum ( 10 ).

Therefore, the present study aimed to evaluate protozoan parasites in the drinking water of different places in Samarra, Iraq.

2. Materials and Methods

2.1. Sample Collection

In total, 100 samples of drinking water were collected in sterilized plane tubes (10-20) ml from 10 places in Samarra, Iraq (i.e., Al-Sekek, Al-Kadesia, Alzeraa, Al-Shuhdaa, Al-Muthana, Al-Shorta, Al-Mamal, Al-Khedraa, Al-Efraz, and Al-Jubereaa), from the beginning of December to the end of February. The water samples were collected in clean and sterilized disposable plastic bottles, and they were then labeled and transported to the laboratory of parasites for parasitology examination.

2.2. Parasitological Detection of Water Samples

Water samples were examined to detect oocysts or cysts of protozoan parasites by using the Direct wet smear, Lugol’s iodine, and Modified Ziehle Nelseen stain methods, The direct wet smear and Lugol’s iodine were utilized to detect Giardia lamblia by the identification of cysts, the Modified Ziehle Nelseen stain was used to detect Cryptosporidium parvum red-pink oocysts ( 11 ), and the Lugol’s iodine was employed for the detection of Entamoeba histolytica cysts ( 12 ).

2.3. Statistical Analysis

The results were analyzed by the SPSS software (version 20), and the significant differences between mean±SD were assessed by the independent sample t-test with a P<0.05 significance level.

3. Results

The present study evaluated the prevalence of parasites in the drinking water of Samarra, Iraq, during different months. The findings indicate that 80% of the collected specimens were infected with parasites (Table 1).

Sample area No of samples under examination No of infected samples Infection percentage (%)
Al-Sekek 11 8 72.7%
Al-Kadesia 8 6 75%
Alzeraa 14 10 71.4%
Al-Shuhdaa 12 12 100%
Al-Muthana 9 9 100%
Al-Shorta 10 8 80%
Al-Mamal 10 5 50%
Al-Khedraa 13 11 84.6%
Al-Efraz 7 7 100%
Al-Jubereaa 6 6 100%
Total 100 80 80%
Table 1.Percentage of the parasitic infection in the specimens collected from different places in Samarra, Iraq

As can be seen in table 1, the highest percentage of infection with parasites (100%) was found in Al-Shuhdaa, Al-Muthana, Al-Efraz, and Al-Jubereaa, whereas the lowest percentage (50%) was detected in Al-Mamal. The percentage of infection in other places were 71.4% in Alzeraa, 72.7% in Al-Sekek, 75% in Al-Kadesia, 80% in Al-Shorta, and 84.6% in Al-Khedraa.

The results also showed that the infection percentage slightly differed in different months of sample collection, and the total percentage was determined at 80% in December, 79.17% in January, and 80.43% in February. It is thus indicated that the highest percentage of infection prevalence (80.43%) was in February (Table 2).

Sample area No of the samples under examination No of infected samples Infection percentage (%)
December 30 24 80%
January 24 19 79.17%
February 46 37 80.43%
Total 100 80 80%
Table 2.Percentage of infection with parasite based on the month of sample collection

Furthermore, three types of protozoan parasites were detected in the studied water samples, which include Entamoeba histolytica (36%), Giardia lamblia (23%), and Cryptosporidium parvum (21%) (Table 3).

Diagnostic parasite Exanimated samples Infected samples Infection percentage (%)
Entamoeba histolytica 100 36 36%
Giardia lamblia 23 23%
Cryptosporidium parvum 21 21%
Total 100 80 80%
Table 3.Prevalence of diagnostic protozoan parasites in the drinking water samples of Samarra, Iraq

4. Discussion

Water pollution is a major problem for human health worldwide since polluted water causes many deaths each year, especially among children and older people. Water pollution includes microorganisms (i.e., bacteria, viruses, and parasites) or chemicals (e.g., heavy metals); therefore, water loses its quality and becomes unsuitable for humans, animals, and plants. In the last 10 years, the number of waterborne diseases, especially those caused by parasites, increased due to the contamination with wastewater since 80% of untreated wastewater is dumped into the environment and pollutes the rivers. Parasitic diseases are transported by the drinking water and cause endemic or epidemic diseases in both developing and developed countries ( 2 ). Therefore, it is essential to take necessary measures to improve the quality of water by the identification of these organisms.

The results of the current study indicated the presence of protozoan parasites, which include Giardia lamblia cysts and Cryptosporidium parvum oocyst, in the drinking water. Cysts and oocysts of parasites were found resistant to environmental conditions and chlorine. Small size (1-17 micrometers) Cryptosporidium spp. oocytes and Giardia spp. cysts can pass through water purification systems and cause an epidemic after drinking water ( 13 , 14 ).

The findings also revealed the presence of Entamoeba histolytica cysts in a ratio higher than other parasites, which is one of the most important parasitic pathogens in polluted water supplies. The leading cause of water contamination with protozoa worldwide is Entamoeba histolytica, which is also responsible for the high mortality rates in children ( 15 ).

Many studies have identified the presence of cysts and oocysts of the three diagnostic parasites (Entamoeba histolytica, Cryptosporidium parvum, and Giardia lamblia) in the drinking water in Iraq. Baqer, Hammood ( 1 ) identified Cryptosporidium parvum and Giardia lamblia in the tank water in Baghdad, Iraq, while Koloren and Ayaz ( 16 ) identified Cryptosporidium parvum in the environmental water in Turkey. Additionally, AL-Samrri ( 17 ) detected Cryptosporidium oocysts in the drinking water in Samarra, Iraq. The present study recommends that efforts should be made to protect raw water from sources of contamination by maintaining water treatment systems. The main source of drinking water contamination with parasites in Samarra, Iraq, is breakages and cracks of drinking water tubes between water stations and houses, as well as the contamination of water in tubes with the contaminated groundwater.

Authors' Contribution

Study concept and design: R. R. H. A.

Acquisition of data: A. S. M. A.

Analysis and interpretation of data: B. I. H.

Drafting of the manuscript: R. R. H. A.

Critical revision of the manuscript for important intellectual content: R. R. H. A.

Statistical analysis: A. S. M. A.

Administrative, technical, and material support: R. R. H. A.

Conflict of Interest

The authors declare that they have no conflict of interest.


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