REVIEW OF LITEATURE 3.1 Global situation Estimated global infection rate for some helminthic parasites such as Ascaris, Hookworm and Trichuris trichiura are 1000 million, 9000 million and 5000 million respectively (Warren and Mahmoud, 1984). Soil transmitted helminthic infestation constitutes are of the major health problem in the world, particularly in tropical and sub-tropical area. (15). This report also explains the important of helminthiasis in public health because of its high prevalence virtually in global, regional distribution. The factor like poor sauceeconomical and sanitary condition, Unhygienic condition, ignorance, illiteracy, human behaviour contribute to the spread of helminthiasis. It is well known that soil-transmitted helminthiases are closely related with the condition of living and environmental sanitation in the community. Soil-transmitted helminthiases are more prevalent among the low-socio-economic communicties where the standards of living, environmental hygiene and health education are inadequate or lacking. It is mostly recognized among the children who are generally exposed for infection and reinfection due to their habits, activities and lack of awareness in personal hygiene (Kan 1982, 1985) (33, 34). The state diagnostic laboratories (USA) examined stool specimens for two periods in 1987 and 1991. In 1987 216,275 stool specimens were analyzed where the most common parasites were nematodes including hookworm (1.52%), T. Trichuna (1.2%) and Ascaris (0.8%). The pattern of transmission was analyzed again in 1991 for 178,789 stool specimen where parasites were found in 19.07%. It was concluded by this study that intestinal parasitism should not be overlooked as a cause of illness in the Vs and prevalence of parasite may be increasing (28). Sorenson 1994, carried out one study in order to find out the relationship between soil transmitted nematode infection and availability of latrines among 1,614 children of 3-12
years of age living in Sri- lanka. Majority of children (89.7%) showed at least one type of soil transmitted nematode. Children coming from good sanitary facilities were found significant lower mean of hookworm eggs. Similar association was also found for Ascanis, T. trichura between the mean egg count and the availability of latrines for children from scattered settlements. Major determinants for ascaripsis and trichuriasis were congested living conditions. However, improvements of sanitary facilities will probably have a more immediate effect on the prevalence of hookworm infection (1994) (29). Sommani et al were carried out a preliminary study in order to know the socio-economic factor eg. age, sex, occupation and migration. The intestinal parasitic infection and its prevalance rate among the residents of flat No. 20 at Huay Kwang Bangkok was conducted for this study. Most of the flat dwellers had good income, good personal hygiene and sanitation. This resulted that they possessed rather low grade of infestation specially the soil transmitted helminthiasis. (Sornamani et al 1980). Hollang et. al were conducted a cross-sectional investigation in 1988 in order to know possible relationship between a range of intestinal helminthiasis and socio-economic status of the participants. On this basis, strong associations were found established between the socio-economic status of the children and infection with Ascaris lumbeicoides, T. trichusa and hookworm. Since the children from poorer socio-economic condition might be more exposed to be infective stages than those from better environment (31). The shape of the age-prevalence causes may be related to the principal mode of transmission eg in the case of hookworm young agricultural workers may come into contact of hookworm infection due to working on contaminated plantations. The communal factors such as water, food or dust are involved as cariers of the invasive stages, the age-related prenalances depends on the immune status of the host than on environmental and behavioural factors (32).
The prevalence of hookworm infecting among inhabitants of the community was 59.95% and high prevalence rate was observed among the agricultural occupational group. The males and females were not found equally infected but difference was not significant. Hookworm infection was found prevalent among the school children who had naturally greater contact with soil which was more contaminated with helminths because of the poor toilet facilities in the community (35). 3.2 Country situation Soil transmitted helminthic infestation is one of the major health problem in Nepal. (Acharya, 1983) reverse that 20 Round worm make off 2.8 gm of Carbohydrate, and 0.5 gm of Protein per day, over the same period of time Hookworm sucks 0.2 ml blood. The consequence of the infestation causes decrease work capacity and productivity of children and adult, slower cognitive development, poor school performance, susceptible to other infection (17). In Nepal helminthic infestation was highly prevalent from the very beginning. Mostly the people resident in the rural area having mostly agricultural based occupation. The information is mainly related to low socio-economic status, poor personal hygiene, poor sanitary condition and ignorance. In Nepal, intestinal parasites remain to be of great health and socio-economic concern. The reported incidence has however, been found to vary from one region to another. The prevalence rate of intestinal parasites was found to be varying from 29.1% to 44.2% (15). A survey of 12 districts of this country in 1985 has revealed the percentage of individuals to be positive between 57.1% and 100% by one of the three helminthic infections depending upon the area sampled (12). Bhaktapur survey in 1983 has indicated high rate of helminthic infection with 94% of individuals been positive for roundworm, 42% for whipworm and 11% for hookworm (11). In 1993, a study reported that 98% parasites infections in Bhaktapur, and 75% in Chapagaon (17). A study carried out in Panchkhal in 1983 has reported that 75% whipworm, 37% hookworm and 17% roundworm (11). Another old study in Panchkhal in 1990 has indicated 89% infection rates among study subject (20). A survey conducted in western Nepal in 1983 has
shown high rate of infection 83.3% of individuals with hookworm, 52.8% with roundworm and 5.5% with whipworm (13). A study carried out in Kathmandu-Valley in 1979 has been published with the report of 51.1% individuals with more than one parasite and separately 63.5% roundworm, 34.5% and 15.1% whipworm and hookworm respectively (14). A study performed in Dhanusha in 1995 has reported that 60.1% individuals have been seen as positive showing 11.6% hookworm followed by 8.5% round worm and 6.3% whipworm infections (5). A hospital based study of about one decade (1985-1995) faecal samples examined in Tribhuvan University Teaching Hospital and Patan Hospital has revealed the prevalence rate of intestinal parasites varying from 29.1% to 44.2% (15). BNMT (British Nepal Medical Trust) has reported 90% individuals of the study population in Bhojpur and Sankhuwasabha districts with worm infestation (17). A Grouch district study has been reported by Dooley Foundation International that the district having 95% intestinal parasite (17). FPAN/IP school health program has studied the school children of Kathmandu Valley in 1990 and found parasitic infection rate 89.57% in 1985 to 56.99% in 1995 in descending order with Ascariasis at top in both studies (20). A study in Kirtipur of Kathmandu Valley in 1987 has found 40% round worm infection, 25.3% whipworm infection and 4.6% hookworm infection (21). A study on seasonal variation of parasite infestations carried out in 1993 has resulted to have the variation between 46% to 55% parasite infestation rates in project area Panchkhal VDC and between 51% and 65% parasites infection rates among self madelatrine users in Fulbari VDC (17). Studies on Kathmandu and Sunsari districts have shown that the cure rate of mebendazole against Ascariasis (roundworm infection), Trichuriaisis ( whipworm infection ) and Ancyclostomiasis (hookworm infection) were 91.2%, 80.5% and 94% respectively (17). Most of the findings of the surveys and hospital statistics as mentioned above show that from 50 to 90 percentages of the people are victims of parasites in Nepal.
Intestinal parasites are very common among children when infection occurs in children all the family members suffer from it. It is therefore, generally recommended to treat all the family members. In Nepal open air defecation is common particularly in the rural areas that facilitates the parasites to easily enter into the individual thus people fall in to risk of all such parasitic diseases. The ova present in the stool can be dispersed far and wide by means of water and air. The factors like unhygienic condition, ignorance and illiteracy contribute to the spread up of the parasitic diseases. The most common mode of spread is by drinking water that is not boiled or decontaminated or the use of dirty water for household purposes (30). A comprehensive survey on intestinal parasites and protozoa was carried out at the Tribhuvan University Teaching Hospital (TUTH) during the spring 1990. A total of 209 persons were surveyed the area from Kathmandu valley with exception of 22 solicited sample of children from Solukhumbu region. The survey resultes high rate of prevalence of intestinal parasites among the children of Solukhumbu region (Alan 1990) (36). Shakya (1997) performed a sample survey on intestinal helminthi in the valley of Surkhet. The study was conducted in the two VDCs namely Katkuwa and Uharganga. The author suggested that supply of drugs and exotic nutritions would be only for temporary benefit. It emphasized to create awareness providing health education to the people regarding local- nutritions-food and its preparation, environment, sanitation and personal hygiene (37). Houston R. and Schwartz E. 1990 studied for Helminthic infections among Peace Corps volunteers in Nepal. The authors have estimated the prevalence of helminthic infection. Out of 994 samples 209 were of volunteers. Among them 41 specimens were positive for helminths for volunteers. There were no mixed helminthic infections, although n 8 samples for ascaris, 6 (3 percent) for trichuris, and 4 (2 percent) for hookworm during their tours. It was concluded that helminthic infection seems to be of low prevalence in volunteers who reside in Nepal (38).
Rai SK et al (1994) briefed about the status of soil-transmitted helminthic infection in Nepal. In this study a retrospective evaluation of the status of soil-transmitted helminthic infection in Nepal during the period from 1985 to 1992 was conduct at the parasitology laboratory, Department of Pathology, T.U. Teaching Hospital in Kathmandu. An average of 6,537 faecal samples were examined each year for the presence of various types of intestinal parasites. The annual rate of positivity of these samples for soil transmitted helminthasis ranged from 18-36.6%. Among the various types of helminths, the most common was ascaris, followed by hookworm. The incidence of ascaris examined constant throughout the study period, while that of other parasites markedly decreased each year (39). All the previous studies related to the present study has been summarised to the extent possible. During the consultation, all the relevant T.U -publications, other institutions and research agencies are consulted in order to generate more information regarding the present study. Popline and Medline computer web even also search for this study in order to collect relevant information. Attempts were made to visit the different research libraries in order to know the research activity in the country about the progress in the field so far as concerned.