Narayan Gyawali, Ritu Amatya, Hari Prasad Nepal
Department of Microbiology,
B P Koirala Institute of Health Sciences,
Dr. Ritu Amatya
This community-based investigation was carried out to estimate the prevalence of intestinal parasitosis in primary school-going children of the Dharan municipality, Sunsari, Nepal from 2007 through 2008. A total of 182 stool samples were collected from 101 male and 81 female children of ages 4 to 10 years. A questionnaire including the factors predisposing to parasitosis, was filled up by the parents of each child. Parasitic examination was carried out by direct wet mount examination and concentration method using 10% formol-ether. The prevalence rate was found to be 22.5%. The result revealed preponderance of Giardia lamblia (11.5%) followed by Entamoeba histolytica/dispar (4.4%), Ascaris lumbricoides (3.3%), hookworm (1.6%) and Enterobius vermicularis (0.5%). Statistically significant difference in the prevalence with respect to age and gender was not seen. However, socioeconomic status, type of toilet used and the practice of hand washing had a strong correlation (p<0.05) with the prevalence of parasitic infection. Abdominal discomfort also had a strong statistical association (p<0.05) with the prevalence of parasitic infection. Proportionally higher infection rate was seen in participants not using filtered or boiled water. Lack of education of mothers and children, improper toilets and failure to practice proper hand washing were perceived from this study as contributors to the acquisition of intestinal parasitic infections.
Intestinal parasitosis (IP) is a worldwide concern. It was estimated to affect around 3.5 billion people globally and 450 million were ill due to parasitic infections (WHO, 2000). Intestinal parasitic infection is a major health problem in Nepal.[2,3,4] It is most common in school-going children, street children, farmers and their children. A study conducted in two rural villages in Chitwan, Nepal, 1999 showed a 44% prevalence of intestinal parasites in school-going children, whereas a similar study amongst children from Pokhara, Nepal, 2004 showed a lower prevalence of 21.3%. The reported prevalence of intestinal parasites varies considerably from one study to another.[6,7] Infection has primarily been attributed to the absence of safe drinking water, improper sanitary habits, poor fecal disposal system, poor socioeconomic status and wide dispersion of parasites within the human communities.
The common intestinal elminths reported from Nepalese children are Ascaris lumbricoides, hookworm, and Trichuris trichiura, with manifestations as varied as malnutrition, irondeficiency anaemia, malabsorption syndrome, intestinal obstruction, and mental and physical growth retardation. In an analysis done in 2004, nearly 66% of school children in Northeastern Kathmandu were found to have parasitic infections and nearly half of them had multiple parasitic infections.[7,8] The prevalence was directly related to their abdominal discomfort and loss of appetite. Similar association with abdominal discomfort was seen in another study from Kathmandu with 62.7% of parasite infected people complaining of the same.
Of the protozoal infections, amoebiasis and giardiasis are most frequently reported. The agents spread faeco-orally through contaminated sources. Although people of all ages may be infected by these organisms, children are more often infected due to compromise in sanitary habits.[1,10]
This study was conducted to determine the prevalence and types of the intestinal parasites in primary school-going children in Dharan Municipality, Nepal.
Materials and Methodology
A cross-sectional study was conducted in Dharan municipality of eastern Nepal during 2007-2008. The Municipality, consisting of 19 wards, had 10,625 primary school-going children (male: 5,461 and female: 5,164) aged 4 to 10 years. Ten wards were selected by simple random sampling and houses were selected by the systematic random sampling method. A total of 182 samples were collected. Informed consent was taken from the parents of all children.
A short questionnaire was designed which included a) socio-demographic data: address, age, gender, socio-economic status and educational status of mother b) behavioral data: types of toilets being used, hand washing habits and types of drinking water c) participant’s present medical history: any complaints of abdominal pain/discomfort, nausea, vomiting, loss of appetite and perianal itching.
Each participant was provided with a standard stool collection container labeled with the participant’s code and a bamboo spike. Instructions were given to the participant and the parents for the collection of stool sample or perianal swab. Perianal swabs were collected only from those with a history of perianal itching.
Collected stools were examined for the presence of parasites macroscopically and microscopically at BP Koirala Institute of Health Sciences, Dharan, Nepal. Microscopic examination was carried out by direct wet mount using normal saline (0.9%), Lugol’s iodine (0.5%) mount and 10% formal – ether concentrated mount. The parasite count was recorded as per field in high power magnification for protozoal cysts and as number of ova per cover slip for helminths.
Statistical analysis was performed using SPSS-11.5 version. Association of demography, personal habits and symptoms were assessed by using the Chi-square test.
A total of 182 primary school-going children participated in the study. The prevalence of IP was 22.5%. Statistically significant differences in the prevalence with respect to age and gender were not seen. However, the socio-economic status, type of toilet used and practice of hand washing had a strong correlation with the incidence of parasitic infection. Although the types of drinking water had no statistically significant difference in the prevalence of infection, proportionally higher infection rate was seen in participants not using filtered or boiled water. Abdominal discomfort and intestinal parasitic infection had a strong statistical association. (Table 1)
The formal–ether concentration technique yielded 41 (22.5%) samples positive for intestinal parasites whilst 37 (20.3%) were positive in the unconcentrated stool. 39 (21.3%) had single type of infection whilst 2 subjects (1.2%) had mixed infection (Giardia lamblia and Entamoeba histolytica/dispar). The commonest intestinal parasite found was Giardia lamblia [21 (11.5%) as single infection and 2 (1.2%) as mixed infections]. The second common parasite was Entamoeba histolytica/dispar [8 (4.4%) as single infection and 2 (1.2%) as mixed infection]. Ascaris lumbricoides was found in 6 (3.3%) followed by hookworm in 3 (1.6%). Enterobius vermicularis was found in one subject (Table 2).
Our study has shown that almost one-fourth (22.5%) of primary school-going children aged 4-10 years were infected with IP. Majority of the children were infected with a single parasite; Giardia lamblia being the commonest followed by Entamoeba histolytica/dispar. Helminthic infections were less prevalent as compared to the protozoal infections, although studies from other parts of Nepal have shown a higher prevalence of soiltransmitted helminthes.[9,12] Dharan is a comparatively developed town with only a small number of people working in the fields and the periodic campaign of anti-helminthic drug administration to the children could possibly explain the lower prevalence of helminthic infections seen in this study.
In this study, the most frequently seen protozoal cyst was of Giardia lamblia (12.6%) followed by that of Entamoeba histolytica/dispar (5.5%). Higher prevalence of Giardia lamblia (73.4%) and Entamoeba histolytica (24.4%) were reported in the study done in school children of Kaski district, Western Nepal in 2005. A prevalence of up to 80% was recorded from Dhungar Rapti, a remote village of Nepal. This abysmal situation was perhaps due to their practice of defecating on the banks of the Rapti river, water which in turn was used for drinking and cleaning purposes. In our study, although statistically not significant, a high proportion of parasitic infection was detected in those who drank water directly from the taps. More than half of our participants belonged to this group.
The prevalence of intestinal parasites was higher where the mother in the household had less than a primary level of school education. There is a strong relationship between a child’s health and the mother’s education. Health indicators for children whose mother’s education level is lower are always worse. A significant association was also seen with the socioeconomic status, the prevalence rate being higher amongst the lower-middle and lower economic classes. A study done from a remote hilly village of western Nepal in 2001 showed a prevalence of 71.4% in the lower economic class people. Dalits (lower caste people) comprised the majority. This can be attributed to their inaccessibility to safe drinking water, unhygienic personal habits due to lack of knowledge and awareness and also indirectly to their occupation as farmers.
Though only a few participants used a pit latrine, this group had a significantly higher prevalence of IP as compared to those using water shield toilets. Pit latrine holds the risk of contaminating the environment via stray animals, flies and insects. It may also contaminate the drinking water if not located adequately away from the water source. The faecooral route of transmission of most of the IP explains the higher prevalence rate observed in the group with inconsistent hand washing practices after defecation.
Abdominal discomfort was the commonest complaint in most of the microbiologically proven cases. It should therefore be taken as a valuable pointer for clinical suspicion of parasitic infection in this age group.
The prevalence shown in this study may be an under estimation since serial stool examinations may have detectedsome more cases. Other sensitive tests like PCR, latex agglutination test, intra-dermal test, and antigen detection by ELISA were not used.
Intestinal parasitic infection is an important public health problem in Nepal. Poverty, lack of awareness, failure to practice proper hand washing after defecation, unsafe drinking water and use of improper toilets are some of the reasons highlighted by this study as causes of parasitic infections. Appropriate health education should be given to children and their parents concerning disease transmission, personal hygiene and safe drinking water. Special programmes should be launched to educate women. Efforts from the municipality to improve the quality of drinking water supply and the types of toilets being used will certainly curtail the number of parasitic infections in Dharan.
Thus, this study emphasises the need for a multisectorial approach to reduce the morbidity and mortality associated with intestinal parasitic infections amongst young children.
We express our gratitude to Prof. S.K Bhattacharya for his encouragement to conduct this study; Mr. Dharanidhar Baral for his help with the statistical analysis; our friends from the community who helped in collection of samples and Ms. Rashmi Shrestha for her assistance in technical works.
1. WHO. World Health Report 2000 – Conquering Suffering Enriching Humanity. Geneva: WHO, 2000.
2. Chandrashekhar TS, Joshi HS, Gurung M, Subba SH, Rana MS, Shivananda PG. Prevalence and distribution of intestinal parasitic infestations among school children in Kaski District, Western Nepal. Journal of Biomedical Science 2005;4:78–82.
3. Rai SK, Kubo T, Nakanishi M, Sumi K, Shibata H, Matsuoka A, et al. Status of soil-transmitted helminthic infection in Nepal. Kansenshogaku Zasshi. 1994;68:625–30.
4. Estevez EG, Levine JA, Warren J. Intestinal parasites in a remote village in Nepal. J Clin Microbiol 1983;17:160–1.
5. Yong TS, Sim S, Lee J, Ohrr H, Kim MH, Kim H. A small scale survey on status of intestinal parasite infection in rural village in Nepal. Korean J Parasitol. 2000;38:275–7.
6. Rai SK, Bajracharya K, Budhathoki S, Khadka J B, Rai KK, Shrestha MK, et al. Status of intestinal parasitosis of TUTH. Journal of Institute of Medicine 1995;17;134–42.
7. Sharma BK, Rai SK, Rai DR, Choudhary DR. Prevalence of intestinal parasitic infestation in school children in the northeastern part of Kathmandu Valley, Nepal. Southeast Asian J Trop Med Public Health 2004;35:501–505.
8. Pokhrel D, Viraraghavan T. Diarrhoeal diseases in Nepal vis-à-vis water supply and sanitation status. J Water Health. 2004;2:71–81.
9. Sherchand JB, Larsson S, Shrestha MP. Intestinal parasites in children and adults with and without abdominal discomfort from the Kathmandu area of Nepal. Trop Gastroenterol. 1996;17:15–22.
10. Saksirisampant W, Nuchprayoon S, Wiwanitkit V, Yenthakam S, Ampavasiri A. Intestinal parasitic infestations among children in an orphanage in Pathum Thani province. J Med Assoc Thai. 2003;86 Suppl 2:263–70.
11. Population of Nepal, Village Development Committee/Municipality, Population Census 2001, HMG, National Planning Commission Secretariat Central Bureau of Statistics.
12. Rai SK, Nakanishi M, Upadhyay MP, Rai CK, Hirai K, Ohno Y, et al. Effect of intestinal helminth infections on retinol and –carotene status among rural Nepalese. Nutr Res 2000;20:15–23.
13. Easow JM, Mukhopadhyay C, Wilson G, Guha S, Jalan BY, Shivananda PG., Emerging opportunistic protozoa and intestinal pathogenic protozoal infestation profile in children of western Nepal. Nepal Med Coll J. 2005;7:134–7.
14. Okyay P, Ertug S, Gultekin B, Onen O, Beser E. Intestinal parasites prevalence and related factors in school children, a western city sample-Turkey. BMC Public Health. 2004;4:64.
15. Ishiyama S, Rai SK , Ono K, Uga S. Small-scale study on intestinal parasitosis in a remote hilly village in Nepal. Nepal Med Coll J. 2003;5:28–30.
16. Beach M. Chinese government tackles environmental hazards. Lancet. 2001 Mar 31;357:1024.
17. Morgan UM, Thompson RC. Molecular detection of parasitic protozoa. Parasitology. 1998;117 Suppl:S73–85
18. Robert R. Rapid tests for diagnosis of parasitic and fungal diseases. Immunoanalyse et Biologie Specialisee 1997;12:232–40.
19. Bruckner DA. Serologic and intradermal tests for parasitic infections. Pediatr Clin North Am. 1985;32:1063–75.