The present study focused on the analysis of the risk factors of diarrhea in Southern Benin. Data have been collected from 442 peasant households on the basis of a stratified random sampling method in the targeted communities, with information on the source of water provision, the location of the village, the usual defecation place, the site of refusing dumping and the presence of trash dump in the vicinity of the household. Data have been analyzed using descriptive statistics. In addition, analyses of variance and log-linear analyses have been applied to test the various factors in the outbreak of diarrheas. Results have allowed a hierarchical organization of the drinking water sources with regards to their use and to the cases of diarrheas (boreholes: p < 0.001; rainwater and territorial water: p < 0.001; wells: p = 0.547 and pipe-borne water: p = 0.277. If we rule out people’s insanitary behaviors, the impact of some risk factors such as the sites of waste disposal (2%) and excreta disposal (1%) is of little influence in comparison to the water supply source and the place of residence, which play respectively for 62% and 30% in the outbreak of episodes of diarrheas in households. It follows that, to curb the diarrhea morbidity, there is the need to improve the water supply policy and the environmental sanitation.
Diarrheic diseases are permanent health concerns in West African countries in general and in Benin in particular. Figures show that these diseases rank third as the most killing infectious diseases in the world with some 2.5 millions of death in 2004, irrespective of age [
The depression of the TCHI community is part of the western segment of the great central clayish depresssion that runs east and west of the sedimentary basin in the south of Benin and which is known as the Lama depression. Covering the Mono and Couffo regions, the depression of the TCHI is located between the plateau of ADJA in the north, that of COME in the south and the non-irrigated lauds of the AGAME in the west. It is comprised between latitude 6˚52' North, latitude 6˚37' south, 1˚58' longitude East, 1˚50' longitude west (
A river known as the Couffo runs through the depresssion. It is 190 km long with a tropical hydrology rate of flow (9.59 m3/s in August and 9.83 m3/s, when there are floods, 0.58 in May and 0. 92 m3/s in times of drought [
Data have been collected on the basis of a semi-structured interview with selected households in the depresssion following a simple random sampling scheme. The total number, n, of targeted people for the survey has been determined using the normal approximation of the binominal distribution [
In (1), n = sample size; p = proportion of households in the surveyed district (p = 88.27%; INSAE, 2002);, = value of the normal random variable of probability value 1–α/2. With α = 0.05,; d = margin of error of the estimation of any parameter to be calculated from the sample of size, n; for d = 3%, the number of households to be investigated have been estimated at 442. A proportional sample has thereafter been used to determine the number of households to be investtigated in a given community, Nr:
;
N = number of households in the community (N = 442); NT = total number of households in the investigation area; the number of surveyed households by community is shown in
Data collected in every household were related to water provision sources, cases of diarrheas known in the household, trash and excreta management and the sanitation in the house.
The effect of the type of population on the choice of a priority source of water provision by a given population has been assessed by applying a two factors log-linear analysis [
Finally, in order to measure the weight of some significant factors of the occurrence of diarrheas, an analysis of variance has been applied to the data related to the effect of each of these factors of the incidence of diarrheas (water provision source, location of the village, the place where children defecate, the refuse dumping site, the usual defecation place, the presence of trash dump in the house yard). The F statistical values of FisherSnedecor have been considered for each factor. In fact, those values show the importance of the number of cases of diarrhea and have been used to draw graphics that illustrate the weight of each factor in the occurrence of diarrhea.
The sources of water supply the most used in the area are wells, boreholes, and rainwater (
Source: INSAE, 2002.
is used varies from one population to the other (
Results of log-linear analysis applied to
Population A: households living and working in the wetland; Population B: households living on the tableland but working in the wetland; Population C: households that living and working on the tableland plateau.
the plateau or in the depression, or that they go and work on the plateau or in the depression, the priority sources are not the same. It is then established that, whatever the type of population, sources differ. The significant interaction reveals that the types of populations do not use the same sources. However, it is mainly the wells, pipeborne water and the other sources (rainwater and water from Couffo River) that help discriminate the most the populations because boreholes are widely used by them.
As for the disposal of domestic waste in the nature, it concerns 55.2% of the households and is generally made not far from the compounds. Only 25.8% of the households dispose their waste at more than 100 m away from the houses. As to the draining of excreta, it is done in two ways: discharge in the environment (74.2%) and the use of common pits that are present in some compounds (25.8%). In addition, animal dejections were noticeable in the compounds of 50.9% of the households.
The mean score of cases of diarrhea by type of population and by source is shown in
The distribution of the average cases of diarrheas per type of population shows that populations C are the ones that experience the most cases of diarrheas (4.82). Then follow populations A and B with 3.94 and 3.58 respectively. The distribution of cases of diarrheas per type of sources indicates that rainwater and river water are responsible for most cases of diarrheas (5.59) followed by water from the wells with a mean score of 4.02 cases. Water that originates from the pipe is responsible for only 1.89 cases of diarrhea on average. Results show that the hierarchical organization of the sources and the distribution mentioned above has an impact on the number of cases of diarrheas in the households (
Results of log-linear analysis show a difference between the types of populations (p < 0.001) and the sources (p < 0.001) with regards to the cases of diarrheas. Thus, the types of populations do not suffer from diarrheas the same way and do not experience the same number of cases. The interaction between the type of population and the source of water supply being significant (p < 0.001), the populations have been assessed in relation to themselves for each source of supply and the sources of supply have been compared for each type of population with the option “sliced” of SAS Software. Results are presented in
With regards to the dumping site, we notice that the average number of cases of diarrhea is 3.85 with the populations which dispose their waste close to the house and 4.34 for the households which take their refuse as far away as a 100 m from their compound, that is, at a fixed point in the radius. That average goes up to 3.16 for those who dispose their waste at a more than 100 m away from the house and to 4.41 for the households which pile up refuse to make small heaps at home before taking them away (
There is a significant relationship (p < 0.001) in the distance between the house and the disposal site and the number of cases of diarrheas taking into account the area (wetland and tableland). Thus, the more distant the site
Typpop: type of population; Source: water supply source; Prob.: probability value at α = 0.05.
Population A: households living and working in the wetland; Population B: households living on the tableland but working in the wetland; Population C: households that living and working on the tableland plateau.
Comm.: community; refdisp: refuse disposal mode; dpsit: dumping site; Typpop: type of population.
of disposal from the house, the less frequent episodes of diarrheas in the household. With regard to cases of diarrhea, neither the savage defecation nor the use of septic pits is responsible for the same number of cases of diarrheas (p < 0.001). The average number of cases of diarrheas considering the usual defecation place is 4.16 for the population who are used to defecating carelessly and 4.05 for those who make use of septic pits. However, data show that the highest number of cases of diarrheas (4.25) is registered in households where children are used to defecating close to the house. Then follow the households where children defecate behind the house (54.11) and those which have a disposal not far from the house (4.10). Obviously these results are barely significant when compared to one another except with the users of septic pits who display an average number of less high cases.
The distribution of cases of diarrheas with regards to factors like space and the management modes of wastes is shown in
This table shows a significant difference (p < 0.001) between communities as to the number of cases of diarrheas, which means that the distribution of cases is made in accordance to two areas (plateau and depression) with different numbers of cases of diarrheas. As for the refuse disposal site and the management mode, there is a high significant difference. It follows that there is a differentiation in the cases of diarrheas with regards to the set variables. The distribution of cases of diarrheas taking into account the inhabited area (plateau and depression) is shown in
The distribution of average cases, with regards to communities, shows that communities which are located in the wetland experience more cases than those living on the tableland. The villages with a high rate of cases of diarrheas happen to be in the wetland whereas those with a low rate are on the tableland. That distribution also corresponds to the water service standard in the local government where the studies have been carried out. Nevertheless, the ordinary defecation places account for the same number of cases of diarrheas (p < 0.364) whereas the comparison of the areas show that communities that are located in the wetland and those on the tableland experience average numbers of different cases of diarrheas.
The comparative analysis of the influence of several risk factors shows that water and space have a great influence on the cases of diarrheas in the households, which means that there is a difference of influence of these factors in the incidence of diarrhea (
From this figure, the hierarchical organization of the F values of the ANOVA on risk factors shows that the supply source (F = 292.71) has the greatest influence (62%) compared to the other risk factors. Then follows the loca-
tion of the village (F = 139.9) with a degree of influence of 30%. The other factors of risk contribute for less than 8% in the morbidity related to insanitary. These are the refuse dumping site (F = 5.92), the usual defecation place (F = 1.03); the place where children defecate (F = 3.84) the present of small dumping for a first level collection of refuse in the courtyard (F = 20.32).
The variation of the incidence of diarrheas with regards to two important risk factors that are water and space is real. Water is then a pathogen factor often cited with the incidence of diarrheas, as it is for many other diseases, in the sense that it constitutes an essential link in the epidemiology chain of many of them [
Variations linked to the environment modulate the expression of diseases according to places and times [
The diversity of the ways people get drinking water, the alternation of the supply sources according to the seasons, the poor access to drinking water and the insanitary conditions are the significant risk factors of cases of diarrheas in rural areas. It follows that throughout the year diarrhea appears endemic with varying episodes according to space, water supply source and healthy behaviors. If the comparative study of the mean score for the different supply modes, the insanitary conditions and for the space has established the association of the incidence of diarrheas to these risk factors, it is then a fact that the benefits of any improvement of these factors should have some impact on the reduction of the incidence of the disease. Hence, there is the need on the one hand to carry out further studies on the seasonal character of diarrheic morbidity in relation to environmental parameters, and to draw the implication of the studies for the economical capacity of households at participating in the sanitation process in order to make policies best adjust to local realities.