Soil-Transmitted Helminth Infection In School Children In South-Eastern Nigeria: The Public Health Implication
C Uneke, K Eze, P Oyibo, N Azu, E Ali
children, infection, prevalence, soil-transmitted helminth
C Uneke, K Eze, P Oyibo, N Azu, E Ali. Soil-Transmitted Helminth Infection In School Children In South-Eastern Nigeria: The Public Health Implication. The Internet Journal of Third World Medicine. 2006 Volume 4 Number 1.
The prevalence of STH infections was assessed among schoolchildren in Onicha, south-eastern Nigeria, using standard parasitological technique. Of the 510 children examined, 86 (16.9%, 95% CI, 9.38-24.34%) had helminth infections. The males were more infected than the females (18.3% vs 15.5%). Individuals aged 4-6 years old had the highest prevalence of STH infection (27.0%, 95% CI, 16. 62-37.38%). The helminths identified were Ascaris lumbricoides (10.8%),hookworm (4.3%), Trichuris trichiura, (1.2%) and Strongyloides stercoralis (0.6%). The prevalence of STH infections increased with increase in the number of persons in the household and the difference was statistically significant (χ 2 = 21.02, df = 3, P<0.05). Stunted growth by 1.6m and 0.04kg weight loss were recorded among the infected children. Treatment of STH infections in school-age children may improve growth but health education can be an effective and safe substitute for repeated deworming and reducing the opportunity for the emergence of drug-resistant helminthes.
Soil-transmitted helminth (STH) infections represent a major public health problem in poor and developing countries and have constituted a universal burden which does not only depend on regional ecological condition but also on local standard of social and economic development of the people . More than one dozen different species of soil-transmitted helminths infect humans, especially in the tropical and subtropical parts of the developing world. However, four nematodes in particular stand out because of their widespread prevalence and distribution that result in hundreds of millions of human infections. These include the large roundworm,
It is estimates that almost 2 billion people are infected with one or more of these soil-ransmitted helminths, accounting for up to 40% of the global morbidity from infectious diseases, exclusive of malaria . The greatest numbers of soil-transmitted helminth infections occur in tropical and subtropical regions of Asia, especially China, India and Southeast Asia, as well as Subsaharan Africa. Of the 1-2 billion soil-transmitted helminth infections worldwide, approximately 300 million infections result in severe morbidity, which are associated with the heaviest worm burdens . The public health importance of STH infections ranked highest in morbidity rate among school aged children who often present much heavy worms infections because of their vulnerability to nutritional deficiency . These infections have been shown to impact negatively on the physical fitness and cognitive performance of the pupils. Intestinal obstruction, anaemia, malnutrition, dysentery syndrome, fever, dehydration, vomiting and colitis are the major complications associated with STH infections . STH infections affect most frequently children in developing countries and are associated with poor growth, reduced physical activity and impaired learning ability[6,7,8,9,10].
It is well established that indiscriminate disposal of human and animal faeces, poor personal hygiene, and inadequate water supply contribute to high levels of STH infections . Soil-transmitted helminths are some of the most common and infective agents of mankind and are responsible for high morbidity and mortality throughout the developing world. This is of great importance in health of many populations in third world countries where illiteracy, poverty, and associated poor environmental sanitation practices have been implicated in the heavy burden of
Materials and Methods
This study was conducted from December 2005 through March 2006 in Onicha located in the southern senatorial zone of Ebonyi State, south-eastern Nigeria. It lies approximately 6 o to 15 o latitudinally and 8 o to 17 o East longitudinally. The population is about 1.05 million people. The climate is tropical and the vegetation characteristic is predominantly the rain forest with an average annual rainfall of about 1300mm and average atmospheric temperature of 30 o C. There are two distinct seasons, the wet and the dry seasons, the former takes place between April and October, while the latter occurs from November to March. The area is traversed by a number of streams and rivers which constitute the major source of water supply to all the communities in the area. Basic amenities are essentially lacking in the area and there are no proper sewage disposal systems in most of the communities. Farming and trading are the major economic activities. Educational status of most of the inhabitants is generally very low and systematic deworming exercise has never been conducted in the area.
The study population comprised of 510 primary school pupils aged 4-18 years old. Four largest primary schools in the area were selected for the study. These included; Community Primary School (CPS) Agbabor-Isu, Community Primary School (CPS) Anioma, Union Primary School (UPS) Amanator, and Central Primary School (CPS) Igboeze-Onicha Primary school pupil were considered for this study because: (i) schools are accessible without much difficulties, (ii) the peak of prevalence of STH infection is to be found in this group  and (iii) experience shows that there is general good compliance from children and parents . Assessment of the knowledge of schistosomiasis was conducted on the pupils, their teachers and randomly selected adults in the communities by interview, to determine the level of awareness of the disease.
The protocol for this study was approved by the Infectious Diseases Research Division (IDRD), Department of Medical Microbiology/Parasitology, Faculty of Clinical Medicine, Ebonyi State University Abakaliki, Nigeria. The approval was on the agreement that patient anonymity must be maintained, good laboratory practice/quality control ensured, and that every finding would be treated with utmost confidentiality and for the purpose of this research only. All work was performed according to the international guidelines for human experimentation in biomedical research . Approval for the study was obtained from the Chairman, and the Secretary Local Government Education Authority (L. G. E. A.), Onicha Local Government Area, Ebonyi State, Nigeria. Approval was obtained from the Parents Teachers Association (P.T.A.) of each school studied and informed consent was obtained from each of the participating pupils. Seventeen pupils declined participation and were excluded from the study. The participating pupils were given biscuits, sweets, pencils, pens, eraser and pencil sharpeners as incentives. Infected pupils were referred to the Primary Health Care Centre PHCC in the area for immediate treatment.
Sampling Technique/ Laboratory Analysis
The pupils were educated on the causes of intestinal helminthic infections among school aged children and they were convinced that every child ought to be free from such infections, thus the necessity of participating in the research work was appreciated by them. Thereafter, wide mouthed corked sterile bottles were given to the pupils for the collection of their stool samples at home and structured questionnaires were distributed among the participating pupils for the collection of demographic information such as age, sex, type of toilet facility used, and number of individuals in the household. The pupils were taught how to collect stool sample and with the aid of their teachers, the questionnaires were correctly filled. The height and weight of the pupils were taken in the morning of the following day as they submitted their stool samples between 7.30 and 8.30am. The stool samples were properly labelled and were carried in a cold box filled with Ice Packs and transported to the laboratory of the department of Medical Microbiology, Faculty of Clinical Medicine, Ebonyi State University Abakaliki, Nigeria, for analysis. The samples that could not be analysed immediately were preserved using 10% formalin until they were examined . Stool analysis was performed using the Kato-Katz technique [18,19].
Differences in proportion were evaluated using the Chi-square test. Statistical significance was achieved if
Out of the 510 (252 males and 258 females) subjects examined 86 (16.9%, 95% CI, 9.38-24.34%) had helminth infections. The males were more infected than the females (18.3% vs 15.5%) but the difference was not statistically significant (χ 2 = 0.69, df =2,
There was no statistical significant difference in the trend (χ 2 = 9.25, df =4,
The prevalence of the STH infection was highest among those using bush method for defecation (33.8%, 95% CI, 26.09- 41.49%), followed by those using pit latrine method (12.8%, 95% CI, 24.08-31.92%). No case of STH infection was recorded among those who admitted using the water closet method. Statistical analysis showed a significant difference in the trend (χ 2 = 13.01, df = 2,
Assessment of mean weight showed little disparity between those infected with STH and those uninfected. The mean height and weight of infected individuals were generally slightly lower than the uninfected. Infected male school children had mean weight of 28.0kg while corresponding mean weight for the uninfected was 29.6kg. Among the females, the mean weight for the infected was 31.4kg, while 33.0kg was recorded among the uninfected (Table 3).
There was also a little disparity between the infected and uninfected school children with respect to height. Infected males had a slightly lower mean height than the uninfected (1.24m vs 1.26m). The mean height for infected females was 1.29m while a mean height of 1.31m was recorded among the uninfected females (Table 3).
In this study a prevalence of 16.9% of STH infection was obtained among primary school children. This is comparable to the STH infection prevalence rate of 15.6% obtained among schoolchildren in Thailand , but was considerably lower than the prevalence rates obtained in a number of other studies including Myanmar (69%) , Kenya (63%) , Ecuador (65%) , Kelatan (56%) , Guinea (53%)  and western Nigeria (64%) . These variable results in prevalence are a reflection of the Local endemicity and sanitary standard, environmental conditions, timing and seasonal differences in the design of the survey work and personal hygiene . The lower prevalence obtained in the present study could be attributed to the timing and the geographical differences in the area. For instance, a similar work conducted in another part of Ebonyi State, Nigeria, between the months of April-June (rainy season and when the soil is usually more humid/wet) recorded 76% prevalence of STH infection , but this current work was conducted between the months of December – March (dry season, when the soil is usually dry). It is well established that wet or damp soil favours the eggs of helminths and rainy season enables them to thrive more than the dry season [29,30]. Similar works done in Zaria and Jos, Nigeria [30,31], revealed that rainy season favours the proliferation of STH infections. More so, it agreed with the report from Vietman , which indicated that helminthic environmental and human behavioural factors influence the transmission process.
Four STH parasites (
Male children were more infected than female children but the difference was not significant (
The measurements of height and weight were conducted in order to verify WHO emphasis of malnutrition and stunted growth associated with STH infection among schoolchildren. In Brazil a 2.4% stunned growth and 0.6% weight loss were observed among infected children . Thus the results from this survey showed stunted growth by 1.6m (5.4%) and 0.04kg (3.2%) weight loss among the infected children. Our observation showed that infected males were shorter and weighed less than infected females. Thus from this study it was obvious that girls demonstrated a better development in terms of growth and weight compared with boys and it is worthy to note that helminthiasis is one of the leading causes of stunted growth and malnutrition among the children which needed urgent attention.
It is important to note that our inability to conduct the survey during both rainy and dry season in order to compare prevalence results from each season was a major draw back. This is advocated in future studies. We conclude that treatment of helminth infections in school-age children may improve growth in areas where malnutrition and helminth infections are prevalent. The Ministry of Health should integrate deworming into the existing health infrastructure so that every time a child is reached for any health service, the child is also de-wormed. However, instructing children and corrects personal habits which are conducive to infection and practice good personal hygiene can be an effective and safe substitute for repeated deworming, reducing the opportunity for the emergence of drug-resistant helminthes, which should prolong the time antihelminthic drugs such as benzimidazoles may be used for treatment of STH infections.
Authors are grateful to the Parents-Teachers Association of all the primary schools used in this study for logistical support.
C.J. Uneke Department of Medical Microbiology/Parasitology, Faculty of Clinical Medicine, Ebonyi State University, P.M.B 053 Abakaliki, Nigeria, Telephone: 234-08038928597, Fax number: 234-04300222, E-mail: email@example.com