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Predominance of Gastrointestinal Protozoan Parasites in Children: A Brief Review | OMICS International
ISSN: 2380-5439
Journal of Health Education Research & Development
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Predominance of Gastrointestinal Protozoan Parasites in Children: A Brief Review

Iram Abdullah*, Hidayatullah Tak, Fayaz Ahmad, Nazima Gul, Shafaquat Nabi and Tanveer A Sofi

Department of Zoology, University of Kashmir, Srinagar, Jammu and Kashmir, India

Corresponding Author:
Iram Abdullah
Department of Zoology
University of Kashmir
Hazratbal, Srinagar-190 006
Jammu and Kashmir, India
Tel: +919419456456
Fax: +278615107002
E-mail: [email protected]

Received date: August 04, 2016; Accepted date: October 11, 2016; Published date: October 17, 2016

Citation: Abdullah I, Tak H, Ahmad F, Gul N, Nabi S, et al. (2016) Predominance of Gastrointestinal Protozoan Parasites in Children: A Brief Review. J Health Edu Res Dev 4:194. doi: 10.4172/2380-5439.1000194

Copyright: © 2016 Abdullah I, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Intestinal parasitic infections are among the major diseases of concern to public health throughout the world [1]. About 25% of world’s population suffers from one or more kinds of intestinal parasitic infections (helminthes/protozoa). Children because of their complex nutritional requirements and less developed immune systems are observed to be the principal sufferers of these parasitic infections [2]. Moreover, they have an extremely delicate physiology which can result in severe upsetting of their biochemical and physiological processes associated with these infections. Intestinal protozoan parasites can affect children in a variety of ways; they cause mal-absorption, reduced growth, increased risk for protein energy malnutrition, reduced psychomotor development and anemia. This report addresses Cryptosporidium, Giardia, and Entamoeba as the main parasitic protozoa of concern among children worldwide.


Immune systems; Protozoan parasites; Cryptosporidium; Giardia; Entamoeba


Intestinal parasitic infections caused by intestinal helminths and protozoa are among the most common human infections endemic throughout the world especially in tropical and subtropical countries including India. About 3.5 billion persons are infected with intestinal parasites and nearly 450 million suffer from clinical morbidity [3]. The protozoan parasites are the more common cause of gastrointestinal disorders compared to helminthes especially in developing countries. A number of intestinal protozoan parasites are reported in different parts of the world like Giardia lamblia, DiEntamoeba fragilis, Entamoeba histolytica, Blastocystis homini, Isospora belli, Cyclospora cayetanensis and Microsporidia. Among them Entamoeba, Giardia and Cryptosporidium are the major protozoan parasites of global public health concern. Protozoan parasites being single celled can rapidly multiply inside the body leading to the development of the serious infection. Most of the protozoan infections tend to be asymptomatic. However, the common symptoms associated with it include abdominal discomfort, vomiting and dysentery [4]. When burden of infection is pronounced, it may cause several complications like diarrhea, malaise, bloating, fatigue, epigastric discomfort, malnutrition, mal-absorption, intestinal ulceration, gastroenteritis, weight loss, abscesses, mental retardation and even death. Protozoan infections can also lead to structural and functional abnormalities of small intestines in humans and can be misdiagnosed as appendicitis or other inflammatory diseases of gastrointestinal tract. Children are the primary victims of gastrointestinal protozoan parasites. So the disease control interventions need to be focused towards the pediatric group.

Giardia lamblia

It is a flagellated protozoan parasite of phylum Sarcomastigophora that colonise and reproduce in small intestines of humans, causing disease Giardiasis. Giardia is most frequently reported as a cause of diarrhea worldwide. Giardiasis can be responsible for severe malabsorption syndrome causing malabsorption of fat, proteins, folic acid, Vitamin A and vitamin B12 and these nutritional deficiencies in turn may lead to serious organ damage [5]. Giardia intestinalis results in stunted growth and poor psychomotor development of children [6]. Giardia infection also results in reduced Hb level [7] and hypoalbuminemia [8,9]. It sometimes infects gall bladder leading to jaundice and colic.

Global burden

Giardia lamblia is the most prevalent protozoan parasite worldwide currently infecting about 200 million people [10]. G. lamblia is known to infect 2% to 5% of population in developed countries and 20-40% in developing countries, majority of which are children [5,11,12] (Table 1).

Country Area of study Prevalence (%) reported Reference
Bangladesh ICDDRB Hospital, Dhaka 0.37 [13]
Egypt Damanhur city 14.8 [14]
Ethiopia North Gondar 41.9 [15]
Ghana Kumasi 0.2 [16]
Iraq Abu-Malah and Harer, Basrah 45.16 and 18.7 [17]
Iraq Kadhmiyah hospital, Baghdad 1.77 [18]
Iraq Erbil/Kurdistan 13.13 [19]
Iran Abyek, Qazvin 3.0 [20]
India Aurangabad 55 [21]
India Barabanki, UP 19.13 [22]
  Buea, Cameroon 21.4 [23]
India Chandigarh 7.96 [24]
India Gujarat 5 [25]
Kenya Thika District 6.9 [26]
Libya Sebha Province 3.19 [27]
Malaysia Inanam sabah 35.48 [28]
Mexico Coacalco-de Berriozabal 18 [29]
Nepal Dadeldhura 7.47 [30]
Nepal Dharan 6.8 [31]
Nigeria Delta and Edo States 0.51 and 3.1 [32]
Oman Dhahira 10.5 [33]
  Gaza, Palestine 10.3 [34]
Philippines Metro Manila 11.6 [35]
Pakistan Muzaffarabad 11.8 [22]
Pakistan Quetta 32 [36]
Rwanda Kigali 3.6 [37]
Thailand Thai 1.56 [38]
Tajikistan Western 26.4 [39]

Table 1: Prevalence of Giardia worldwide.

Entamoeba histolytica

It is a protozoan parasite of phylum Sarcomastigophora that colonizes and reproduces in large intestines of humans, causing disease Amoebiasis. The disease may remain restricted to intestinal lumen or invade intestinal lining causing Amoebic dysentery. It not only causes severe diarrhea but can also result in extra intestinal manifestations including rectal bleeding, amoeboma, toxic megacolon, pneumatosis coli, peritonitis and abscesses in the intestine, liver, lung and other organs. Entamoeba histolytica is reported to be responsible for deaths of approximately 1,00,000 persons per year, second only to another protozoan infection, malaria [1].

Global burden

Nearly 10% of the world’s population is infected with E. histolytica, the majority being in developing countries. Most of the infected individuals tend to be asymptomatic while the minority of cases develops clinically apparent disease. E. histolytica is known to result in 50-100 million cases of colitis or liver abscesses per year and up to 100,000 deaths annually [13]. Amoebiasis is the third leading cause of death from parasitic diseases world-wide with its greatest impact on people of developing countries (Table 2).

Country Area of study Prevalence (%) reported Reference
Bangladesh ICDDRB Hospital, Dhaka 1.11 [13]
Cameroon Buea 24.4 [23]
Egypt Damanhur city 16.8 [14]
Ethiopia NorthGondar 27.3 [15]
Ghana Kumasi 8.5 [16]
Iraq Sulaimani district 4.05 [41]
Iraq Abu-Malah, and Harer, Basrah 23.87 and 30.93 [17]
Iraq Kadhmiyah hospital, Baghdad 9.80 [18]
Iraq Erbil/Kurdistan 30 [42]
India Barabanki, UP 28 [22]
India Bhopal 25.4 [43]
Japan Hanoi, Vietnam 2 [44]
Kenya Thika 14.6 [26]
Lesotho Qacha’s Nek 24 [45]
Mexico Coacalco-de Berriozabal 10 [29]
Malaysia Inanam sabah, 83.87 [28]
Nigeria Nigeria 8 [46]
Nepal Dehran, 6.1 [31]
Philippines Metro Manila 2.9 [34]
Pakistan Quetta 29 [35]
Pakistan Muzaffarabad 5.9 [22]
Rwanda Kigali 54.5 [37]
Tajkistan Western Tajkistan 25.9 [39]
Thailand Thai 0.03 [38]
Uganda Kampala 2.5 [47]

Table 2: Prevalence of Entamoeba worldwide.

Cryptosporidium parvum

It is a small coccidian protozoan parasite belonging to Phylum Apicomplexa that infects the microvillous region of epithelial cells of the digestive tract in humans. Cryptosporidium causes moderate to severe diarrhea in the immunocompetent individuals due to malabsorption and increased secretion. In the immunocompromised individuals, the condition can be prolonged and dangerous. Cryptosporidium infection of the intestinal epithelium is associated with villous atrophy, hyperplasia of intestinal crypt cells, and inflammation of the lamina propia. Cryptosporidiosis can sometimes lead to extra-intestinal complications like respiratory cryptosporidiosis, cholecystitis, hepatitis and pancreatitis [48].

Global burden

Global statistics on prevalence of Cryptosporidium parvum shows that it infects 2-50% of population worldwide [3]. In Asia and Africa, the infection rate ranges from 5-10% (Table 3).

Country Area of study Prevalence (%) reported Reference
Bangladesh ICDDRB Hospital, Dhaka 4.44 [13]
Ethiopia Girar Jarso and Dera, 7.3 [49]
Ethiopia Pawi, northwestern Ethiopia 8.1 [50]
Egypt Cairo 15.3 [51]
Ghana Kumasi 8.5 [16]
Ivory coast Yamoussoukro 36.93 [52]
Iran Isfahan 4.6 [53]
Iraq Baghdad 2.3 [54]
India Dehli 27.4 [55]
India Uttar Pradesh 33.33 [56]
Jamaica Kingston 4.3 [57]
Kenya Kenya 4 [58]
Mexico Coacalco-de Berriozabal 4 [29]
Netherlands Netherlands 21.8 [59]
Nigeria Zaria 4.5 [60]
Palestine Gaza 16.3 [61]
Philippines. Philippines. 1.9 [62]
Saudi Arabia Makkah 4.07 [63]
Uganda Kampala 1.5 [47]

Table 3: Prevalence of Cryptosporidium worldwide.

Intestinal Protozoan Infections in Kashmir Valley

In Kashmir valley the studies conducted so far demonstrate the presence of protozoan parasites Giardia intestinalis, and Cryptosporidum parvum among chidren. Besides this a number of helminth parasites have also been reported especially Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis Taenia saginata Hymenolepis and Ancylostoma [64,65] (Table 4).

Prevalence reported (%) Area of study Reference
Giardia Entamoeba Cryptosporidium    
9.20     Srinagar [66]
12.28     Srinagar [67]
7     Srinagar [68]
    36 Srinagar [69]
73.5 17.35   Jammu [48]

Table 4: Prevalence of Gastrointestinal Protozoan Parasites in Kashmir.

New Approach for Parasite Detection

Diagnosis of intestinal protozoa is made usually by microscopy after staining fecal smears with iodine or any other stain. This technique is being widely used for diagnosis of intestinal protozoa [10,70-74]. However nowadays molecular diagnostic tests are increasingly being used for both clinical as well as research purposes. They involve identification of specific antigen or DNA of parasite in stool or serum samples through Enzyme linked immunoassay (ELISA) [22-24] or direct fluorescent antibody assay [25-27]. These molecular methods besides having high sensitivity for parasite detection help in differentiation of various species of parasite with the help of PCR.

Control and Prevention

In view of high prevalence of protozoan infection and the morbidity they cause, the measures aimed at their control and prevention need to be strengthened. Steps should be taken to reduce the infection rate to the levels at which they cease to be of public health significance. The prevention and control of protozoan diseases can be primarily achieved through improvement in personal as well as environmental hygiene [75]. The most effective control can be achieved by involving the community to participate in its own disease control. For this purpose, mass awareness programmes should be conducted to make the people aware about the various infectious agents and their modes of transmission, encourage hygienic practices, recommend use of safe drinking water, avoid defecation in open areas, and prioritize primary health care. Moreover, standard techniques should be used by clinical microbiologists for screening the stool samples to increase the chances of detection of parasites and chemotherapy option should be used for treatment of individuals diagnosed with protozoan infections.


Gastrointestinal disorders caused by various protozoan parasites impose a great burden on human populations in the developing world, particularly among children. The need of the hour is that we should have enough epidemiological information on the prevalence of gastrointestinal protozoan infections and their associated risk factors in different localities which are a prerequisite to develop quality control measures.


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