Occurrence of enteric parasites and their risk factors among the female inhabitants of lower socioeconomic groups in Dhaka city

The present study was conducted to investigate the intestinal parasites. A total of 900 female inhabitants of lower socioeconomic groups in Dhaka city were examined during Sep 2013 to Aug 2015, prevalence of gastrointestinal parasitic infestation was 66.22% and 26 parasite species were identified, of which ten species were protozoans, six cestodes, four trematodes and six nematodes. Prevalence of nematoda was the highest (57.55%), then cestode (38.67%), protozoa (19.22%) and lowest was found in trematode (4.11%). Entamoeba histolytica (10.44%) indicates severe faecal contamination among protozoan parasites, while in cestodes Hymenolepis nana (22.78%), in trematodes Fasciolopsis buski (2.11%) and in nematodes Ascaris lumbricoides (38%) were highly prevalent. In twelve study areas, the highest prevalence was found in Kamrangichar (87.5%) and children of age group 1-15 years (75.65%) were mostly affected by intestinal


Introduction
Intestinal parasitic infections are the most prevalent in the world, with an estimation of 3.5 billion people infected and 450 million ill (WHO, 2001).While mortality from enteric helminths and protozoa is relatively low, morbidity and the indirect effects of apparently asymptomatic infections have a substantial impact on health and quality of life.The World Bank (1993) estimates the global burden of disease from geohelminth infections (A.lumbricoides, T. trichiura and hookworm) to be 2.4 million DALYs.In Latin America, the Pan American Health Organization (PAHO) (1997) estimates that helminth infections affect between 20% and 30% of the general population, with prevalence as high as 60-80% in endemic areas.In Bangladesh, among the helminthes and protozoan parasites, A. lumbricoides, A. duodenale, T. trichiura, E. vermicularis and E. histolytica, G. lamblia are common (Kuntz 1960;Islam et al., 1975;Saha and Chowdhury, 1981;Banu et al., 2003;D'Silva et al., 2003;Uddin et al., 2005;Khanum et al., 2008).Parasitic diseases continue to cause significant morbidity and mortality throughout the world irrespective of the patient's immune status.It is estimated that in developing regions of the world, there are approximately 340 parasite species capable of infecting humans (Garcia, 2001).Diarrhoeal diseases are extremely common in the developed and developing worlds, affecting millions of individuals each year (Guerrant et al., 1990).In Bangladesh, one third of the total child death burden is due to diarrhoea (Victora et al., 1993).Every year, a rural child suffers on average from 4.6 episodes of diarrhoea, from which about 230,000 children die (Mitra, 1994).The intestinal parasitic infections persist and flourish wherever poverty, improper hygiene, lack of access to clean drinking water, low standards of community and individual sanitation and poor health education, insufficient health care and overcrowding are entrenched (Khanum et al., 2010).Intestinal protozoan infections are even more prevalent; Entamoeba histolytica is one of the deadly species and is associated with pathological abnormalities in liver and large bowel in human body (Khanum et al., 2010), and is estimated to cause severe disease in 48 million people, killing 70 thousand each year (WHO, 2002).G. intestinalis is the most common protozoan infection of the intestinal tract.Many countries, especially developing countries, show a high infection rate of giardiasis (Sprong et al., 2009).Trichuriasis is a potentially serious disease that can cause colitis (inflammation of the colon), chronic iron deficiency anaemia and chronic dysentery (Bundy and Cooper, 1989).Hymenolepis nana is the most common parasitic cestode prevalent globally (Pillai and Kain, 2003).There were around 1000 million cases of ascariasis due to Ascaris lumbricoides, and 500 million cases of Trichuris trichiura infection worldwide (WHO, 1990 andBundy et al., 1992).The aim of this study is to estimate the prevalence of intestinal parasitic infestation.In developing countries like Bangladesh intestinal worms are really threats to child and adolescents health.Although the intestinal helminthiasis is extremely wide spread in Bangladesh, they do not always cause immediate fatalist, acute illness or disabilities, so their presence has long been ignore and neglected to the people's mind (Khanum et al., 2008(Khanum et al., , 2010)).

Study design
A cross sectional study was carried out during September 2013 through August 2015 among 900 female inhabitants of lower socioeconomic groups in twelve areas of Dhaka city.The age groups were categorized into 4 major groups: Children (1 to 15 yrs), Adult (16 to 35 yrs), Middle age (36 to 50 yrs) and Old age (51 to 70 yrs).To study the prevalence of intestinal helminthes, stool samples were collected and processed by Formolether concentration technique.

Data Collection
Standard questionnaire was developed and the data were collected by face to face interview.After filling the questionnaire, an empty plastic container was provided to the all of female inhabitants for collecting stool.The stool samples were processed and prepared for microscopic examination in the laboratory of the Department of Zoology, University of Dhaka.

Laboratory analysis
To find out the prevalence of intestinal parasites, stool samples were collected and were examined in laboratory.The Formol-Ether concentration technique was performed according to the method described by Cheesbrough (1987). 1 g of faecal sample was mixed with 4 ml of formol water, again 3-4 ml of 10% formol water was added and mixed by shaking for about 20 seconds then strained it.3-4 ml formol ether was added with sieved suspension in a conical tube and mixed for 1 minute, it was then centrifuged at 3000 rpm for 1-2 min, the parasites were sedimented to the bottom of the tube.The sediment was examined using 10X objective with the condenser.The 40X objective was used to identify the small cysts and eggs.And the data generated was analyzed by the SPSS Software-17 for mean analysis.

Prevalence of parasites in different study areas
In 12 study areas, highest prevalence was found (87.5%) in Kamrangichar, and lowest 30% found in Hajaribag (Figure 6).Kamrangichar is an island Thana surrounded by mainly Buriganga River.The population is very dense in this area they live in unhygienic environment, there is lack of fresh water supply, lack of sanitary latrines, defaecate in open areas, they walk barefooted most of the time and most important this area is surrounded by polluted Buriganga River which facilitates the growth of intestinal parasite.Hajaribag was urban Thana of Dhaka metropolitan city where chemical pollution occurred mostly as many chemical factories found there; as a result survival of parasite's egg and cyst in that environment is very low because of that chemical pollution that's why lower prevalence of infection observed there.In different study areas, the prevalence of protozoan parasites was comparatively higher in Shahidullah hall (43.33%).In case of cestodes, highest prevalence was found in Kamrangichar (71.25), in case of trematodes, highest observed in Hajaribag (15%) and among nematodes, highest recorded in Moghbazar (70%) (Figure 7).

Parasitic prevalence in age groups
Considering all of the four age groups, the highest prevalence (75.65%) was found in children group (1 to 15 years) (Figure 8).Relationship between age and prevalence of parasitic infection (r = -0.284,p = 0.716) was not significantly correlated.Inverse correlation implies that as age increase prevalence tend to decrease due to better immune response in upper ages.Similar high prevalence (73.3%) was found in children by Ara et al. (1997).According to Steketee (2003) and Garzon (2003), children are the worst affected.This could be due to the fact that child are exposed to environmental hazard favoring parasitic infections.In another study by Uddin et al. (2005), highest (87.50%) was also noted among aged 12-14 years, Singh et al. (1984) recorded a maximum of 92.5% from 5 to 9 years of age but Khanum et al. (2010) found lowest prevalence in 08-10 years age group.The infestation of nematodes found highest in all age groups, among children (28.49%) and adult age group (10.40%), protozoa were the 2 nd highest infestation group.Highest infestation (13.98%) of cestodes was observed in children group (Figure 9).

Conclusions
The prevalence of helminthiasis and protozoan infection is widespread in Bangladesh.The female inhabitants of the slum areas were more vulnerable to parasitic infestation due to the differences in hygienic conditions, rate of literacy, malnutrition, status of anaemia, and prevailing socioeconomic condition.Under above circumstances incidence of intestinal parasites is likely to be common.Information on the prevalence and intensity of human intestinal parasites of the people of Dhaka city is very meager.Such information is necessary in planning the control of parasitic infection.

Conflict of interest
None to declare.

Figure 1 .
Figure 1.Overall prevalence of different parasitic groups.

Figure 2 .
Figure 2. Prevalence of protozoan parasites found in female inhabitants.

Figure 3 .
Figure 3. Prevalence of cestode parasites found in female inhabitants.

Figure 4 .
Figure 4. Prevalence of trematode parasites found in female inhabitants.

Figure 5 .
Figure 5. Prevalence of nematode parasites found in female inhabitants.

Figure 6 .
Figure 6.Prevalence of intestinal parasites among the female inhabitants in different study areas.

Figure 7 .
Figure 7. Prevalence of different parasitic groups among female inhabitants in different study areas.

Figure 8 .
Figure 8. Overall prevalence of parasitic infection in different age groups among the female inhabitants.

Figure 9 .
Figure 9. Overall prevalence of parasitic group in different age among female inhabitants.