Intestinal Parasitic Infection among School Children in Golestan Province, Iran
Infections by intestinal parasites are a major public health problem worldwide, especially among children in developing countries. It causes nutritional deficiencies and anaemia. As, the prevalence of parasitic infection is different among various population, there is a need for periodical prevalence evaluation to an appropriate control strategy. The goal in this study was to determine the prevalence of intestinal parasitic infections in primary school children living in Gorgan, north of Iran. A cross-sectional survey was conducted on 800 schoolchildren aged 8-12 years of Gorgan city, capital of Golestan province, located in the north of Iran in 2011. Three stool specimens were collected from each student. Specimens were examined with direct wet and formalin ethyl acetate method. Data were analyzed with SPSS version 16 software. A total of 800 schoolchildren were screened. Nearly one third of students (28.8%) were infected with one or more intestinal parasites. The most common parasite were Giardia intestinalis (9.9%; 79/800) and H. nana (1.5% ; 12/800), respectively. The data showed that Children living in crowded family (≥3) were more susceptible to infection also take care of animals in house helps to transmission of parasite infections as there was a significant association between that and rates of parasite infections (p-value<0.05). The prevalence of infection was also much more common in those students whose parents were less educated. A high percentage of school children were infected to intestinal parasites, so, intervention programs including health education and environmental sanitation are required.
Received: November 20, 2012;
Accepted: February 04, 2013;
Published: March 09, 2013
Infections by intestinal parasites are a major public health problem worldwide,
especially among children in developing countries. WHO estimated that approximately
3.5 billion people are infected by intestinal parasites and about 450 million
children are ill due to these infections WHO, 2000: Warunee
et al., 2007). Infections with intestinal parasites may have important
health consequences and cause iron deficiency anemia, growth retardation in
children and other physical problems (Scolari et
al., 2000; Nasiri et al., 2009). The
type of infection is much different depending on the behavioral factors and
the geographical regions.
It is necessary to conduct periodic studies for information of intestinal parasitic
infections in the general population. There are previous studies that has reported
different prevalence rates of parasitic infection in various areas of Islamic
Republic of Iran (Sayyari et al., 2005). Although,
there have been a few reports of infection rates of intestinal parasites in
some local areas of Golestan province (Saebi, 1998),
no extensive epidemiological survey in the area has been conducted. The objective
of this investigation was to study intestinal parasitic infections in primary
school children living in Gorgan to estimate their prevalence, their association
with socio-economic characteristics and the influence of simple and primary
hygienic measures in reducing their frequency.
MATERIALS AND METHODS
Study group: A cross-sectional survey was conducted in 18 primary schools
of Gorgan city, capital of Golestan province, located in the north of Iran.
This survey was performed between October 2010 and March 2011. The sample size
was calculated according to the prevalence of 27%, based on the results of previous
studies Daryani and Ettehad, 2005, at precision of 0.07
and at 0.05 significant levels. 800 school children from both boys and girls
ranging from 8 to 12 years old were conducted to this study.
Study design: Parents of the participating children filled out a questionnaire
on common risk factors for parasite infections, as described in literature questions
on environmental risk factors were related to living background; those on sanitary
risk factors to water supply (piped water); those on socioeconomic risk factor
to household income (6 000 000 Rial/month or less) (Ostan
et al., 2007) and education level of the parents (less than 12 grades
or higher). Behavioral factors were eating with unwashed hands (yes or no),
eating unwashed/raw vegetables (yes or no), eating unpeeled/unwashed fruit (yes
or no), biting fingernails/sucking thumb (yes or no) (Herrstrom
et al., 1997; Rai et al., 2005; Asaolu
et al., 2002).
Intestinal parasitic examinations: An oral description and specific instructions for handling and contamination avoidance of the stool specimen were given to all the children. All stool specimens were preserved in 10% formalin before examination at the department of Parasitology, Faculty of Medicine, Golestan University of Medical Sciences. In the Parasitology lab, stool samples were examined macroscopically for visible proglottides or adult helminths. Then each sample concentrated using formalin-ether sedimentation technique for microscopic examination. Protozoan parasites were examined by staining with loguls iodine solution using light microscopy at high (400 X) magnification. Ova of helminth parasites were examined by direct wet-mount observation at low (100 X) magnification.
Ethical considerations: The present study was approved by the Ethics Committee of the Faculty of Medicine at Golestan University of Medical Sciences and all students and their parents were aware from the study objective and were content to participate in this survey.
Statistical analysis: For statistical computations, SPSS (Chicago, IL, USA) program for Windows, version 16 were used. Statistical differences of the data were analyzed by Chi-square tests or Fishers Exact test where appropriated at 0.05 significant level. Consent forms were signed by the parents of participating schoolchildren.
RESULTS AND DISCUSSION
A total of 800 schoolchildren were screened. The participating children were
482 (60.25%) boys and 318 (39.75%) girls. The mean age of the participants was
8.5 years. The response rate to the questionnaires was 100%. The overall prevalence
of parasite infection among the participants was 28.8% (230/800). Giardia
intestinalis and Hymenolepis nana were the most common protozoa and
helminth infections, respectively.
No statistically significant difference was observed between the prevalence rate of intestinal infection across gender (p = 0.22) and age (grade of education) (p = 0.80). Prevalence was highest in the 8-11 years age group (34.1-32.1%) children, respectively.
The prevalence of parasitic infection increased by family size including 39.1% (27/69), among the families having ≥3 children (p<0.05). There was no significant relation between prevalence of parasitic infection and parent's education level (Table 2). The prevalence rate of infection was lower in those students (28.2%) whose fathers were employer (673/190) and more among those students (31.4%) whose fathers were not employer (127/40).
The most common intestinal pathogenic and nonpathogenic parasite were Giardia intestinalis (9.9%; 79/800) and Blastocystis sp. (15.2%; 122/800), respectively. The rate of contamination with protozoa was 26.1 and 3.6% for intestinal helminthes. The prevalence rates of Hymenolepis nana, Ascaris lumbricoides, Enterobius vermicularis, Entamoeba histolytica/dispar and hook worms among participants were 1.5, 0.5, 1.2, 1 and 0.4, respectively. 10.5% of boys and 8.8% of girls were infected to intestinal parasites.
The frequency distribution and Prevalence of intestinal parasites infection among the schoolchildren are indicated in Table 1. Table 2 describes the distribution of environmental, socioeconomic, sanitary and behavioral risk factors among the children in the respective areas and municipalities. Significant associations were found between infections and take care of animals in house as well as brother, sister number (p-value<0.05) (Table 2). No statistically significant relationship found between rate of intestinal parasite infection and education levels of parents, household income, using pipe water, biting fingernails/sucking thumb, eating unpeeled/unwashed fruit/vegetables and washing hands before eating or after toilets
Nearly one third of students (28.8%) aged 8- 12 years in North of Iran, Golestan
Province were infected with intestinal parasites. Recent reports in Iran, showed
a prevalence rate of intestinal parasites ranging from 18.4 to 29.75% in general
populations (Nematian et al., 2008; Sayyari
et al., 2005). There are many epidemiological studies of intestinal
parasites throughout the Iran, reported similar results including 30% in Kerman
in 1991 (Valian and Sharifi, 1993); 37.3% in Islamshahr
in 1992 (Godarzi, 1993); 59.4% in Tehran in 1994 (Rohanni,
1994); 30.5% in Zabol in 1997 (Baraoe and Sharifi, 1996);
48.2% in Isfahan in 1998 (Baghaie et al., 1999);
56.6% in Qazvin in 2000 (Mahyar et al., 2000);
39.4% in Mashhad in 2001 (Salehabadi, 1990); 28.5% in
Babol in 2001 (Ghahramanloo et al., 2001); 49.6%
in Robatkarim in 2005 (Soheil Azad et al., 2005);
13.7% in school children in Semnan Province in 2005 (Atashnafas
et al., 2006); 13.7% in Jahroom in 2007 (Davami
et al., 2008).
||Frequency distribution and prevalence of intestinal parasites
in school children of Gorgan city according to gender
|OR: Odd ratio, CI: Confidence interval
||Distribution of environmental, socioeconomic, sanitary and
behavioural risk factors among the school children of Gorgan city
|*Statistically significant differences, OR: Odd ratio, CI:
However, there are national Study in Islamic Republic of Iran that reported
the prevalence of parasite infection 19.3% in general population and 25.5% in
the children aged less than 15 years (Taheri et al.,
2011). The results of the present study revealed that the prevalence of
intestinal infection was higher than that reported in comparison.
Giardia intestinalis and Blastocystis hominis, the first and
second most common protozoa in the present study, both can be transmitted orally
through drinking water. Concerning polyparasitism, our results are comparable
to those of Keiser et al., (2002) obtained in
western Cote dIvoire. The observed multiple infections could be explained
by the facts that many species of protozoa have the same mode of transmission
and that hygiene is poor in these areas. Blastocystiss sp. and G.
lamblia were found in samples from all the localities studied.
Because there are no reports of parasites from Gorgan so we could not compare
our results with previous data. It should be mention that in most of the surveys
performed in Iran and in other countries, G. intestinalis was the most
common intestinal protozoa among the residents of rehabilitation centers as
well as normal populations, that are in concordance with the present study.
For example The prevalence rate of G. intestinalis was 37.4% in students
of southwest of Tehran in 1985 (Garoz, 1985); 25.3% in
Kerman's students in 1991 (Valian and Sharifi, 1993);
19% in children of north of Tehran in 1992 (Nazari, 1992);14.2%
in Islamshahr in 1992 (Godarzi, 1993); 17.2% in Lahijan
in 1997 (Saraei and Rezaian, 1997); 40% in elementary
school of Yazd in 1998 (Saebi, 1998); 29.8% in Mobarakeh
in 2001 (Atashnafas et al., 2006); 24.1% in primary
school students of Babol in 2001 (Ghahramanloo et al.,
2001); 38.1% in Birjand in 2002 (Taheri et al.,
2004); 18.5% in Robat karim in 2005 (Soheil Azad et
al., 2005); 8.4% in Semnan in 2005 (Atashnafas et
al., 2006); 8.1% in Jahrom in 2007 (Davami et
al., 2008); 18.5% in Gorgan in 2008 (Touhidi and
Mostafa, 2009); and 28.7% in South Khorasan Province in 2011 (Taheri
et al., 2011).
One of the important risk factor for the parasite infection is water supply.
Giardiasis outbreaks have occurred from the contamination of drinking water
supplies (Wilson, 1998). Giardia spp. as a cause of water-borne
disease of human has been increasingly recognized over the past 10 years (Zuckerman
et al., 1999). Also In water supplies of different parts from the
world the cyst of Giardia spp. have been isolated (Okyay
et al., 2004).
In our findings, the prevalence of H. nana was 1.5%. H. nana
has detected from many part of Iran especially in western areas. The prevalence
of this parasite was reported 20% in Bandar Abbas and Minab (Saebi,
1998), 14.7% in Zahedan (Fazaeli et al., 1997),
13% in Khozestan and Gonbad Kavous (Saebi, 1998), 3.9%
in Kerman (Ziya Ali and Masuod, 1997), 3.8% in children
of Birjand (Taheri et al., 2004).
In previous studies (Sayyari et al., 2005), ascariasis
was high prevalency in most area of Iran for example 83% in Khozestan; 81% in
Tabriz; 78% in Kermanshah; 72-97% in Isfahan; and 14-60% in Mazandaran; but
1-4% in Sistan and Bandar Abbas. According to the results of this study, the
prevalence of ascariasis was 0.55% such as the results of mentioned study in
various parts of Iran (Sayyari et al., 2005; Valian
and Sharifi, 1993; Godarzi, 1993; Soheil
Azad et al., 2005; Taheri et al., 2011).
These data declare that prevalence of ascariasis has been decreased a lot between
the last 10-15 years. It means that the public health knowledge about the ascariasis
disease has increased in different populations.
In this study The prevalence of E. vermicularis was 1.2%. In other studies
that use non specific stool examination method for E. vermicularis detection,
the prevalence of this parasite was 0.2% in Kerman (Nasiri
et al., 2009), 0.4% in Jahrom (Davami et al.,
2008), 0.7% in Zabol (Baraoe and Sharifi, 1996)
and 2.9% in Islamshahr (Valian and Sharifi, 1993). In
other studies with specific examination method (Scoth test), E. vermicularis
was prevalent. For example the prevalence was 22.1% in Birjand in 2002, 54.1%
in Ramsar in 1990, respectively (Sayyari et al., 2005).
Many studies on the prevalence of intestinal parasitic infections have been
performed in developing countries, due to their wide diffusion in this continent,
reported the same results. In most of these areas, G. lamblia was the
most dominant infection. The prevalence rate of the intestinal parasitic infections
in mentally retarded individuals in the world, were 76.67% in Egypt (Mohamed
et al., 1991), 66.4% in northeastern part of Nepal (Sharma
et al., 2004); and 54.2% in Combodia of Korea (Lee
et al., 2002); 46.7% in Srinaga of India (Wani
et al., 2007); 31.8% in Aydinca, west of Turkey (Okyay
et al., 2004); 30% in Abha, Saudi Arabia (Omar
et al., 1991), 14.6% in Tripoli of Libya (Ben
Musa et al., 2007).
We did the study among schoolchildren because they were one of age groups the most exposed to intestinal parasites and were generally accessible.
The data of the study showed no significant difference between sex of children
and intestinal parasitic infection Even though gender was not a significant
risk factor for the prevalence of intestinal parasitic infections, males were
more likely to be infected (10.5%) than females (8.8%) in the present study,
which is consistent with other reports (Kim et al.,
2003; Noor Azian et al., 2007; Arani
et al., 2008). Children living in crowded family (≥3) were more
susceptible to infection. The data also showed that take care of animals in
house helps to transmission of parasite infections as there was a significant
association between that and rates of parasite infections (p-value<0.05).
The correlation between children health status and parents education
is well known (Zuckerman et al., 1999). However
in this study, the degree of parents education was not significantly associated
to rates of infection, as were other factors such as hand washing and washing
vegetables and fruits.
In conclusion, the study showed that intestinal parasites are remarkable among school children in Gorgan, thus, intervention programs including health education and environmental sanitation are required.
We gratefully acknowledge the students, parents and school staff who participated in this study. This project was financially supported by Golestan University of Medical Science, project No. G/P/35/2073.
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