Introduction
Intestinal parasitic infections are among the major problems of public health in the developing countries. It is estimated that 450 million people, the majority of whom are children, are now diseased as a result of these infections [1]. The prevalence of intestinal parasitic infections in each community is considered as an indicator for the health status of the area. Some personal factors including safety conditions, nutrition, health status, literacy, cultural habits as well as environmental factors such as climate, geographical location, poverty and economic situation, inadequate health conditions, high density of population and failure to observe health regulations in people working in the preparation and distribution of food may help the prevalence of intestinal parasitic infections [2]. These infection are associated with restricted linear growth, physical weakness and low educational achievement in patients, especially children [
1]. Furthermore, chronic intestinal parasitic infections have become the subject of speculation and investigation in relation to spread and severity of other infectious diseases including viral infection, tuberculosis and malaria [3]. In the developed countries, intestinal protozoan parasites are known as an important cause of gastrointestinal disorders, enteric protozoa are one cause of diarrheal disease in children.
Intestinal parasitic infections are mainly transmitted through the fecal-oral route [4]. Common intestinal parasites such as
Giardia intestinalis and
Blastocystis hominis are still health challenges of economically developed and developing countries [4-5].
Blastocystis hominis is the most common human intestinal protozoa worldwide. It was associated with diarrhea in the tropics and subtropics since it was found in patients throughout the world. The reported prevalence rates of intestinal protozoa varied from 1.5% to 10% in the developed countries with much higher rates of 30% to 50% in the developing countries [6]. At present, parasitic diseases are among the hygienic problems in Iran. With regard to social, economic, and geographical conditions and population changes of Iran, this country is an appropriate arena for growth and reproduction of all kinds of parasites [
2]. The aim of this study was to determine the frequency of intestinal parasites in the population who had referred to medical centers of Shahid Sadoughi University of Medical Sciences in Yazd.
Materials and Methods
This is a clinical-based retrospective study that lasted for a period of two years (2015-2016) and was conducted in the medical centers of Shahid Sadoughi University of Medical Sciences in Yazd. Patients in all age groups, both genders with or without gastrointestinal disturbance, were included in this study. The study was approved by the Ethics Committee of Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
First, to check the consistency of the stool, the presence of blood, mucus and the adult worm parasites were evaluated microscopically. Finally, using the direct and formalin-ether concentration methods, the stool samples were checked by optical microscope to assess the presence of parasite eggs, cysts and trophozoites. All the parasitic cases (protozoa and worms) were reported separately. All data (age, sex) were obtained from the main registry at the medical centers of Shahid Sadoughi University of Medical Sciences. The frequency data were compared using the Chi square (X
2) test. Odd ratios were calculated for gender and age. The SPSS20 software (SPSS Inc., Chicago, IL, USA) was used for statistical analysis.
Results and Discussion
A total of 31000 patients with suspected intestinal parasites were referred to the medical centers of Shahid Sadoughi University including 15,686 males (50.6%) and 15,314 females (49.4%) the majority of whom aged between 1 and 11 years (34.6%). The patients were then diagnosed with one or more intestinal parasites over the study period (Table 1). Also from all of the screened samples, 3.8% (N=1154) were positive for intestinal parasites. In general, protozoan infections (3.60%) showed a higher prevalence pattern compared to the helminthic infections (0.20%) (Table 2). Among the parasites identified,
Blastocystis hominis (1.75%) and
Giardia lamblia (1.45%) were found to be the commonest, followed by
Chilomastix mesnilii (0.35%) and
Hymenolepis nana egg (0.11%). Other uncommon parasites encountered were
Trichomonas hominis (0.05%),
Enterobius vermicularis egg (0.08%) and
Ascaris lumbricoides egg (0.01%) (Table 2). No statistically significant difference was found between intestinal parasites and sex (p> 0.05). Distribution of intestinal parasites in terms of age groups is shown in figure 1. Prevalence of
Blastocystis hominis and Giardia lamblia was higher in the younger than the older population. The prevalence of other parasites was relatively equal across all age groups. Although the frequency of intestinal parasites in different age groups did not differ significantly in 1-11 years age-group, the highest rate of infection was observed (p>0.05). In addition, a statistically significant difference was found in patients infected with
Giardia lamblia and Hymenolepis nana (p< 0.05). In contrary, no statistically significant difference was identified among age-groups infected with other parasites (p> 0.05) (Fig. 1). Intestinal parasitic infection of humans is a major health problem in many tropical and sub-tropical parts of the worldespecially in the developing countries such as Iran. Several epidemiological studies have been conducted to determine the prevalence rate of intestinal parasite infections in Iran [4]. Patterns of intestinal parasitic infections in the population, may have changed because of socio-demographic characteristic, life style, human behavior, nutritional habituate and sanitary/ hygienic improvements [
4-6].
The present study showed that about 3.8 % of the study population were carriers of one or more of intestinal parasites. Prevalence of intestinal parasites vary in different parts of Iran with 10.7 % reported from Tehran (Capital of Iran) [5], 4.7 % in Karaj [6], 6.1 % and 8.6% in Yazd (Central of Iran) [
10] and 5.92 % in Qazvin (North of Iran) [1]. Socioeconomic, geographic, sanitary/hygienic, cultural, and nutritional factors may contribute to this fact.
Table 1. Prevalence of intestinal parasitic infections in patients referred to medical centers of Shahid Sadoughi University of Medical Sciences in Yazd in 2015-2016