INTRODUCTION

Today, infectious diseases, which used to wreak havoc in Europe till mid 19th cen­tury, are being regarded as diseases of the underdeveloped world. In Western countries, infectious diseases and nutri­tional problems no longer dominate infant mortality and morbidity. However, in de­veloping countries the reverse was the case. Mortality attributable to communi­cable diseases, maternal and perinatal conditions and nutritional deficiencies were reported to be more than five times as frequent in low and middle income countries as compared with high income countries (Alvarez-Dardet & Ashton 2000). Also, the World Health Organiza­tion (1998) reported that “of more than 50 million deaths worldwide in 1997, about one-third were due to infectious and parasitic diseases such as acute respi­ratory diseases, tuberculosis, diar­rhoea, HIV/AIDS and malaria”. These infectious diseases still remain leading causes of premature death among adults in the de­veloping world (Lindgren et al. 2005).

The above facts, to some extent, un­derscore the importance of infectious diseases in understanding morbidity in a developing country like Nigeria. Further­more, with the emergence of new infec­tious diseases which are resis­tant to well established antimicrobials, and the HIV/AIDS scourge for which an effective cure is yet to be found, the need for greater attention to be paid to preven­tive health care cannot be over stated (Huang 2004; Jones et al. 2008).

Several studies have shown that dis­ease occurrence and distribution in a population was not a random event (Lindgren et al. 2005; Jha et al. 2002). The process of transmission of water re­lated diseases have been found to be influenced by factors relating to the host, the individual, and the environment. Multi–level researches have been con­ducted in recent times to describe envi­ronmental (ecological) effects and indi­vidual level effects on transmission of diseases. Most of them have implicated “social class” or “socio–economic status” in the epidemiology of infectious dis­eases (Poortinga et al. 2008; Abayawardana & Hussain 2002).

Egboka et al. (1989) observed that in Nigeria, “outbreak of water-borne dis­eases such as cholera, yellow fever, dysentery, diarrhoea, and guinea worm occur peri­odically resulting in fatality”. Guinea worm is reported to be wide­spread in many rural districts throughout central and southern Nigeria. An esti­mated 650,000 Nigerians suffered from guinea worm infections every year (Kinley 1989; Egboka 1989). Though considerable pro­gress has been made since, but the problem still persists, albeit at a much lower level (Brieger et al. 1997).

In Anambra State, South–Eastern Nige­ria, majority of the riverine communities lived in poverty and illiter­acy, with their beliefs and social practices steeped in their traditional cultural belief sys­tem. Also notable was the conspicuous ab­sence of basic infrastructure and social amenities, especially water, roads, elec­tricity and health facilities. The socio-economic and cultural environment ex­posed these communities to greater risk of infectious diseases.

The environment has been implicated as an important factor contributing to morbidity. There was a widespread belief that environmental quality was a major determinant of health and well–being (Fenwick 2006; Osuafor 1997; Cairncross & Feachem, 1983). The relationship between polluted drink­ing water and spread of cholera was es­tablished by John Snow in his study of the epidemiology of cholera in London, from 1848 to 1854 (Park 1997).

Water related diseases have been tra­ditionally presented in four categories: (1) Waterborne, are faeco-orally transmit­ted through contaminated water or food. Ex­amples are cholera, typhoid, diar­rhoeas, poliomyelitis etc. (2) Water–washed, are due to insufficient quantity of water used e.g. trachoma, scabies etc. (3) Water-based, the pathogen spends a part of its life cycle in a water snail or other aquatic animals, e.g. schistosomi­asis and guinea worm. Lastly, (4) water-related insect vector, spread by insects which either breed in water or bit near water. e.g. malaria and onchocerciasis (Park 1997; Mera 1997).

Numerous studies have shown the re­lationship between certain diseases and water pollution and contamination (Fenwick 2006). Other sig­nificant variables linked to morbidity in­clude socio-economic factors as meas­ured in terms of per capita income, edu­cation, housing, employment (Obermeyer 1993; Trinder et al. 2000); lifestyle (Evans et. al. 2000; Bitton & Mckea, 2000); increased human intrusion into tropical forest for purpose of mining, farming, settlement, and tourism (Demany 1996); foreign trade and ex­panded markets for imported foods, which occasionally contain bacterial or viral contamination (Demeny 1996; Mera 1997). Ethnicity is believed to be related to epidemiology of a number of diseases. This was due to the fact that ethnic back­ground implied group homo­geneity of diet, hygiene, education, religious and other customs that influ­ence human health (Vallin & Behm 1980). Age, sex and stress are also known to influence morbidity differentials (Ramalingaswani 1994; Miles 1991). Several studies have also associated certain diseases with seasonal and cli­matic changes (Miles 1991; Kendall 1991).                                                                              

There are a range of theories such as epidemiological transition, multi-factorial causation theory, socio–economic depri­vation theory, epidemiological triad, Ajzen’s theory of planned behaviour, health belief model, political economy of morbidity etc. that could be useful in ex­plaining the character and pattern of morbidity in a community. The theories of multi-factorial causation, political econ­omy and economic deprivation were con­sidered most appropriate for explanation of morbidity differentials in this study. The multi-factorial causation recognizes that disease predisposition is influenced by a number of factors, which were linked to socio–economic status, cultural, genetic and environmental variables. Most of these factors are linked to man’s life-style and behaviour patterns. The Economic Deprivation theory is applied here to look at morbidity from the point of view of par­ticipants’ socio-economic status, which is mostly determined by societal forces. In Nigerian society, the social structure plays a primary role in social placement. Those at the lower social strata are likely to experience greater health problems. The position adopted in this study is that the morbidity differential is produced by the social system which creates social inequality and socio-economic depriva­tion.

From the political economy perspective, people’s beliefs and actions may play an important role on their health status. However, the socio-political economy plays a more primary and deterministic role. The theory suggests that “the possi­ble range of health statuses and health behaviours of individuals is limited by their location in the social and economic system. As a result, a significant change in the health behaviour of any group of individuals is seen to require altering the social and economic context within which they live” (Minkler et al. 1995). 

In this study, the focus was on water-related diseases generally, but with spe­cific emphasis on those that were trans­mitted through oral consumption of con­taminated water. Specifically, this study tried to identify the frequency of water–borne diseases such as typhoid, cholera, diarrhoeal illnesses, dysentery, infectious hepatitis and poliomyelitis as a result of exposure to untreated or contaminated water in the communities studied. It also explored those socio-economic factors as well as cultural beliefs and practices that influence the susceptibility of the people to water borne diseases. It sought to identify differences within and between the communities studied in relation to the occurrence of the water borne diseases.

MATERIALS AND METHODS

This was a retrospective, cross sectional survey on water-borne disease experi­ences of riverine communities in three Local Government Areas (LGA) of Og­baru, Anambra East and Anambra West in Anambra State, South-Eastern Nigeria. In this study morbidity was investigated from a multi-factorial causation perspec­tive, with emphasis on the social, cul­tural and economic background of the people. Six communities were sampled from the three LGAs studied. The com­bined population of the six communities were projected by Nigerian Population Com­mision (NPC 2000) at 87,636. A total sample of 1200 respondents repre­sent­ing 600 households was drawn from the six communities. The data collection process focused on heads of the house­holds, using a set of structured question­naire. In addition, 600 cases were re­viewed from hospital records in the communities studied.

To ensure representativeness of the communities and households, a combi­nation of the following sampling tech­niques was adopted – quota, cluster, systematic random and simple random. Method of data analysis included fre­quency distribution tables, percentages, and analysis of variance.

Ethics approval was sought and ob­tained from the University of Nigeria eth­ics committee.

RESULTS

Table 1 shows that 51.5% are females, while 48.5% are males. Over sixty per­cent (67.6%) of the respondents were engaged in either farming or fishing. Only 11.4% were civil servants or profession­als. This is a typical characteristic of rural communities. The respondents were pre­dominantly Christians (61.5%), while 38.5% belonged to the African Traditional Religion. A greater percentage of the re­spondents, i.e. 49.8% had no formal educa­tion. This is followed by 34% with primary level education. The population can best be described as predominantly rural, illit­erate and agricultural in nature. These facts influence their economic status, lifestyle and possibly their health status.

Typhoid and intestinal worms comprise 25.4% and 19.3% respectively. Preva­lence of dysentery was also quite signifi­cant (15.4%). Poliomyelitis had the least percentage frequency of 0.9% (Table 2).

Review of 100 cases randomly col­lected from hospitals and/or health cen­tres located within the six communities is presented in Table 3. Most of the health facilities were health centres and as such were not equipped to deal with serious health problems like infectious hepatitis, chol­era, typhoid and so on. Most of such suspected cases were either re­ferred out or were taken to hospitals out­side the LGAs. The result generally re­veals that water related diseases rank higher than other diseases. For instance, malaria, which is a water-related insect vector disease, ranked highest among all dis­eases found in all the communities with over 50% occurrence. The next high ranking diseases were gastro­enteritis and diarrhoea.

The analysis of variance was used to test the significance of difference ob­served in the occurrence of WBDs in re­lation to a range of variables.  It was hy­pothesised that prevalence of WBDs de­creases as the level of education of household heads increases. A two-way ANOVA was used to test this hypothesis. The result gave an F value of 10.81 and 12.26 for prevalence and edu­cation re­spectively, which were signifi­cant at a p value of <0.001, indicating that there was a significant difference in the prevalence of WBDs in relation to level of education. The conclusion here was that prevalence of WBDs tends to reduce with increased level of education of the household heads.

It was hypothesized that some occupa­tional groups experience higher preva­lence of WBDs than others. This hy­pothesis was tested using a two-way ANOVA, which gave F values of 7.00 for prevalence and 9.70 for occupation, with significance at P value < 0.001. An ob­servation of the disease distribution showed that the greatest disease burden was borne by those in farming/fishing occu­pation, with 49.2%, followed by un­skilled labours with 19.3%. The lowest burden of WBDs was found amongst those in the professional category with 1.8%.

Table 4 shows considerable variation in the distribution of WBDs amongst the communities. The highest morbidity bur­den of 22.1% was found in Nzam, the headquarters of Anambra West Local Government Area. This is followed closely by Ogbakuba with 18.7%. On the other hand, Otuocha has the lowest bur­den of 12.1%. The variation was mainly due to the source of water used, with riv­ers and ponds being the major contribu­tors.

The Latin Square Design (a three-way ANOVA) was used to determine the level and significance of interaction between community, prevalence and water source available to the communities (Ta­ble 5). Re­sult of the analysis shows sig­nificant dif­ference in the prevalence of water-borne diseases at P=0.001 level of signifi­cance in the general distribution of these diseases and also, with regard to the sources of water used. When in­terac­tion between different variables is meas­ured, the result shows that there is a sig­nificant difference between communities and the water they use as well as between prevalence of the different wa- ter-borne diseases and the water source available to the communities. The es­sence of this Latin Square Design was to establish the points of interaction and the significance of such interactions between different variables.

DISCUSSION

This study specifically relates toinfectious diseases that re­sulted from domestic use of contami­nated water. Water-borne dis­eases were quite prevalent in Nigeria (Rooy 1987; Egboka 1989; Kinley 1989). Although the riverine people have more water in their environment than other communities living in the upland, most of the water available to them were pond, river, and stagnant lakes, which were subject to contamination and as such are not suitable for consumption. The streams were used for household chores, including bathing (especially in the river), washing of plates, clothes and also served as sources of drinking water. The result of this was that it led to frequent outbreaks of water-borne diseases, often reaching epidemic levels.

Results of this study showed significant differen­ces in the prevalence of water borne dis­eases.  This was found to vary with the level of education of the house­hold heads, being higher among those with lower education level. There was also a significant variation in the preva­lence with regard to the sources of water used in the households. There were also differ­ences in the prevalence of WBDs ob­served between the communities due to source of water available to them (Ta­ble 4).

The higher prevalence of WBDs amongst those in farming and fishing households could be explained by their poor living conditions and lifestyle. Farm­ing and fishing tend to be done as a col­lective household activity, exposing them to the same risk conditions. The epide­miology is driven by the fact that they drink from the same source, using shared utensils. Moreover, the type of water commonly available to them in the farm was pond, river or streams, which were most often unfit for consumption.

The study indicated some social and economic factors that influence the prevalence of WBDs. In the riverine ar­eas the people are predominantly farm­ers and fishermen. A good number en­gaged in petty trading on agricultural produce. They lived in typical rural set­tings, with very poor road networks most of which became impassable during rainy seasons. Also, the health facilities were inadequate, and most boreholes were broken down, with the few functional ones producing murky and undrinkable water. Due to widespread poverty, most of the people could not afford sanitary facilities, and this predisposed them to high risk of disease.

Due to low level of education and poor awareness of water related health issues, prevalence of WBDs were high. How­ever, above and beyond all these internal factors, it is important to recognise that these communities are located and oper­ate within a wider socio-economic and political system which they have no influ­ence over, but which determines their living condition. Explaining the morbidity among the people require wider under­standing of the social-eco­nomic and po­litical forces. This is primar­ily why this study is predicated on Multi­factoral Cau­sation theory, Economic Deprivation the­ory, and Theory of Politi­cal Economy, all of which calls for a broader consideration of factors beyond the cultural beliefs and practices of the people to avoid ‘blaming the victim’ that characterises many socio-psychological theories such as the Health Belief Model. As Minkler et al. (1995) noted, “the pos­sible range of health statuses and health behaviours of indi­viduals is limited by their location in the social and eco­nomic system. As a result, a significant change in the health behav­iour of any group of individuals is seen to require altering the social and economic context within which they live”.

The problems of social inequality and marginalisation with all its ramifications were quite glaring in these communities. If the sanitary conditions in the communi­ties are allowed to continue as they were, the occurrence of serious outbreaks of cholera and increased prevalence of ty­phoid, diarrhoea, dysentery, intestinal worms and other water related diseases would be inevitable.

In view of the above discussions, it could be argued that the political econ­omy plays a primary role in the determi­nation of the health status of the people. The differences in the prevalence of wa­ter borne diseases between groups within the communities, and between the communities are a function of the type of water available to them. While some of the communities had access to safe portable water, some did not. Our data revealed that the prevalence of WBDs was higher among households and communities with unsafe water source, compared with those that relied on safe portable water.