Introduction

Human intestinal parasites are parasites that populate the gastro-intestinal tract of humans. It has become a major health problem in many developing countries^8,24,28. There are two main types of intestinal parasites: helminths and protozoa. In their adult form, helminths cannot multiply in the human body. Protozoa, however have only one cell, and can multiply inside the human body, which contributes to their survival and enables serious infections to develop. Sometimes two or more can cause infection at the same time, a concept known as polyparasitism.^6,7,8,24 Intestinal helminths are distributed worldwide, particularly in tropical and sub-tropical areas of the world. More than one billion of the world’s population including at least 400 million school children are chronically infected with Ascaris lumbricoides, Trichuris trichiura and the hookworms.²⁸ The prevalence of infections and degree of factors predisposing to infection vary from one region to another.¹⁵ Intestinal parasitic infections are among the most prevalent of human parasitic infections worldwide. ^12,23,27 They had been long recognized as an important health problem especially among Nigeria Children.^{2,14,18,19,26} Several epidemiological studies had indicated high prevalence rates of intestinal infections among Nigeria children.^10,18,24,28 Few studies had also indicated a direct correlation between the intensity of infection with hook worms and with Ascaris lumbricoides and iron deficiency anaemia and intestinal obstruction.^6,7,26 Majority of Nigerian Children from low socioeconomic class has been found to be anaemic, stunted with retarded growth and underweight due to malnutrition, all due mainly to intestinal parasites.^20,28

Materials and Method

Study area

Subjects

Collection of sample

Laboratory Investigation

Data Analysis

Results

Out of a total of 492 subjects examined, 190 (38.62%) were infected with one or more of the intestinal parasites. Age distribution of the prevalence of infection did not show a definite pattern but infection rate was highest among the subjects in the first decade of life (56.3% ) and least among the subjects aged 60 years and above (30.0%) (Table 1). This observed difference in prevalence by age was not statistically significant (p>0.05). Despite the fact that the subjects examined were not diarrheal patients and do not manifest major symptoms of intestinal parasitic infection, infection rate was relatively high in the population.

Entamoeba histolytica was the most prevalent parasite amongst the population (43.9%) while Giardia lamblia showed the least prevalence (12.4%) (Table 1). Comparing the distribution of parasites within the age groupings, Entamoeba histolytica was most encountered among the subjects in the first two decades of life while hookworm infection was most frequent among subjects aged 20 – 49 years in relation to the prevalence of the other parasites within each age grouping.

Table 2 indicated that males showed a higher prevalence of intestinal parasite infections (40.31%) than the females (36.58%). However, this is not statistically significant (p>0.05).

In Table 3, Occupational prevalence showed that infection rate was highest among the farmers (60.94%), followed by the pupils and pre-school children (59.09%) while the civil servants showed the least prevalence (30.17%) of infection with intestinal parasites. Difference in occupational prevalence was found to be statistically significant (p<0.05). Two infected patients whose detailed information could not be obtained were also accounted for in disease distribution by epidemiological factors.

Distribution of intestinal parasite infections based on their major sources of drinking water showed that subjects who depend on the streams as their major source of drinking water recorded the highest level of prevalence, followed by those that drink well water while the subjects that depend on pipe-borne water and sachet water as major sources of drinking water recorded the least prevalence of intestinal parasite infections. This difference was statistically significant (p<0.05).

Figure 1

Table 1: Prevalence of Intestinal Parasite Infections by Age

Figure 2

Table 2: Prevalence of Intestinal Parasite Infections by Sex

Figure 3

Table 3: Prevalence of Intestinal Parasite Infections by Occupations

Figure 4

Table 4: Prevalence of Infections by the Developmental Status of Their Communities

Figure 5

Table 5: Prevalence of Intestinal Parasite Infections by Educational Status

Figure 6

Table 6: Prevalence of Infections by the Major Source of Drinking Water

Figure 7

Table 7: Prevalence of Intestinal Parasite Infections by Epidemiological Factors

Discussion

This study found that the overall prevalence of intestinal parasite infection was highest between the ages <10 to 39 years, even though the observed difference in prevalence by age was not statistically significant. This study contradicts the work of Oguoma et al who reported highest prevalence in the ages 9-10 years among children from resident homes in Owerri Metropolis.¹⁸ Even though WHO confirmed that intestinal protozoan parasite (IPP) are dependent on age and greater severity of the infection is found in the younger children.²⁹ This could be attributed to the different host responses and other related factors such as the nutritional status.¹

Despite the fact that the subjects examined were not diarrheal patients and do not manifest major symptoms of intestinal parasitic infection, infection rate was relatively high in the population. This concurs with the study by Oguoma et al who identified higher prevalence rate of infection among the studied resident homes who were not presented with any symptom of infection than the subjects in health institutions. ¹⁸ Entamoeba histolytica was the most prevalent parasite amongst the population while Giardia lamblia showed the least prevalence. This observation agrees with the work of Roche et al where Entamoeba hystolitica and E. dispar recorded the highest in prevalence,²² but differs with the work of Alakpa et al who reported that Cryptosporidium sp was the most prevalent intestinal pathogenic parasite in Lagos Nigeria especially among diarrhoeal cases in adults, while Giardia was found amongst those aged 6-10 years.³ These results and those other works done by Ogbe and Odudu; Ndifon; Kogi et al;Gundiri and Akogun, showed that parasites particularly hookworms and Ascaris, are common throughout much of Nigeria.^16,15,13,11 The relatively high prevalence of helminths (27.4% for hookworm, and 25.2% for Ascaris) observed here agrees with previous findings in parts of Northern Nigeria.^4,13 Several other reports from other parts of tropical Africa have shown very high (>70%) infection rates of intestinal helminths.⁹ Variations in prevalence rate of intestinal helminthiasis from different rural communities could be related to several factors including people’s level of education, standard of personal/environmental hygiene and perhaps social habits. More so, some ecological factors such as temperature, relative humidity, rainfall, different diagnostic techniques employed by various workers could be responsible for observed differences in prevalence between communities.²¹

This work also showed that the males had a higher prevalence of intestinal parasite infections than the females. This may be due to the common feeding pattern in which a great number of men eat outside their homes while on daily activities to earn a living. Prevalence is not dependent on sex among the sampled population which disagrees with the work of Atu et al in 2006 who observed a higher prevalence of intestinal parasite in females than in males.⁵

Occupational prevalence showed that infection rate was highest among the farmers (61.0%). This could possibly be due to the unhealthy practices of walking bare footed while farming and the rampant defecation in the farm lands, followed by the pupils and pre-school children (59.1%) while the civil servants showed the least prevalence (30.2%) of infection with intestinal parasites . Difference in occupational prevalence was found to be statistically significant (p<0.05).

Two infected patients whose detailed information could not be obtained were also accounted for in disease distribution by epidemiological factors.

The rural residents recorded the highest prevalence of infection (43.0%), followed by the semi-urban residents (37.5%) while those from the urban settings recorded the least prevalence of infection (36.4%) The explanation could be because of poor knowledge on health education practices on preventable diseases and cultural farming practices. By their educational status, there was an association between prevalence of infection and level of education. Chronological pattern in the prevalence of infection, ranging from the non-educated who recorded the highest prevalence of infection(45.2%), to the subjects that attained the tertiary level of education who recorded the least prevalence of infections (34.9%) . However, these differences were not statistically significant (p>0.05).

The study also revealed that subjects who depend on the streams as their major source of drinking water recorded the highest level of prevalence(44.8%), followed by those that drink well water (41.3%) while the subjects that depend on pipe-borne water (15.6%) and sachet water (15.4%) as major sources of drinking water recorded the least prevalence of intestinal parasite infections. This difference was statistically significant (p<0.05). This could be due to due natural use of local streams for different purposes with the antecedent contamination coupled with poor hygiene practices common amongst the people.

Also observed in the study was the significant prevalence level of parasitaemia amongst those who indulge in the habit of eating raw vegetables (76.7%), habit of neglecting to wash their hands after handling stools(44.9%), walking bare footed(65.4%), swimming in water(47.0%), and lack of intermittent de-worming(43.4%).

Conclusion

What is needed is to adopt drug treatment for those already infected similar to the National Immunization Program to alleviate the sufferings of the already infected population, and prevent the parasites they harbor from passing into the environment and infecting others. Sanitary improvements such as safe, efficient and hygienic management of water (from extraction, through transport and storage, to use, particularly for drinking); safe, efficient and hygienic disposal of feces as identified by Oguoma et al ¹⁸ is important with a regular and effective use of water (with a scouring agent like ash or soap) for hand washing after contact with stools. Hygienic food preparation; and health education to encourage individuals to adopt behavioral change is advocated.

Estimates of these parasitic diseases thus become a matter of necessity for the surveillance of public health, proper health-care delivery and people’s welfare. These findings will generate some scientific interest amongst clinicians and scientist, so that the much needed study will focus more on the epidemiology of these neglected intestinal parasites, and will be compared with the prognosis of the patients.