Introduction: Cholera is one of the so-called dirty hand diseases. Its effective response saves lives. The city of Lubumbashi has recorded at least one cholera epidemic for almost ten years, each of which generates sign ificant socio-economic costs. Method: We conducted a case-control study on cholera in the city of Lubumbashi in the Democratic Republic of Congo in 330 individuals, including 110 cases matched to 220 controls. The linear list of the cholera treatment center was used to identify the cases. Results: Half of the respondents were 50, 30% did not treat water before drinking, and the remaining 49.70% used the treatment of drinking water. The risk factors for the cholera outbreak that were found to be statistically significant include: poor food preservation (AOR = 3.32, 95% CI [1.85 - 5.96], and p value = 0.0001), contact with a cholera patient (AOR = 2.88, 95% CI [1.65 - 5.01], and p value = 0.0002) and stay outside Lubumbashi (AOR = 4.18, its 95% CI [1.83 - 9.55]). Conclusion: An urgent need for information on risk factors for cholera and a rapid organization of the response is the key to cope with this recurrent epidemic in the city of Lubumbashi.
Cholera is an acute diarrheal infection caused by the ingestion of food or water contaminated with Bacillus Vibrio cholerae [
This disease came out of its traditional focus of Bengal and the Upper Ganges Valley in the early nineteenth century to spread throughout the world, along the trade routes, in the form of successive pandemics. Six pandemics followed each other from 1817 to 1859, killing tens of thousands of people in Asia, Europe and America to such an extent that a conference was held in Paris in 1851, inaugurating the internationalization of public health problems [
After having been ravaged by cholera during these first six pandemics, the northern countries (Europe and the United States of America) have succeeded in eliminating this disease as a public health problem through sanitation and improvement actions which have access to drinking water all in a context of development and improvement of the overall living situation of the populations [
Cholera is the preferred companion for natural disasters and conflict situations with massive population displacements. However, it can occur in a context of political stability and in the absence of any natural calamity, when the socio-economic conditions of the populations are favorable to its development [
Africa is currently the continent that reports more than half of all cholera cases and deaths worldwide. 190,549 cases and 2231 cholera-related deaths were reported worldwide in 2014; it has 105,287 cases and 1882 deaths, representing respectively 55% and 84% of the global total [
The Kampemba Health District is one of the 11 Health districts of the Provincial Health Division of Upper Katanga. It straddles between two administrative communes of the city of Lubumbashi, namely, the communes of Kampemba and Annex. This health zone covers a total population estimated in 2016 at 430,935 inhabitants (source: population growth of 3% over the population of 2015), spread over 22 health areas. It has 80 integrated health facilities including 5 hospitals and a reference General Hospital.
Only two health facilities are state-owned and all 78 are private. It has an area of 150 km2, with a density of 2873 inhabitants/km2.
Note that the Kampemba General Referral Hospital is eccentric in the far East of the Health Zone.
The main causes of morbidity are malaria, typhoid fever, acute respiratory infections, diarrhea, cholera, measles.
This is a case-control study, which spanned the entire duration of the cholera epidemic in the health zone of Kampemba from January to June 2016.
The study population consisted of the inhabitants of the Kampemba Health Zone.
To select the cases, we used the registry and the linear list of cholera cases admitted to the Cholera Treatment Center of Kenya which is the only Cholera Treatment Center that receives all the patients of the city of Lubumbashi. Patients were admitted on the basis of the WHO cholera case definition and a positive agglutination test performed at the beginning and end of the epidemic.
From this linear list, we have returned that taking back only the patients of the Health District of Kampemba who were 326 patients during the study period. Our frame was obtained excluding children under 5 years; then we selected the cases to investigate by performing a simple random sampling using the ALEA function of Microsoft Excel 2013.
Based on the addresses, age and sex of the cholera cases retained and found on the linear list of the cholera treatment center, we were able to identify and recruit the witnesses to be investigated either in the same house, or in the same plot, or among the neighbors or in default on the same avenue taking into account the same sex and the difference in age with the case which should not exceed 5 years.
The sample size was calculated using the StatCalc function of the Epiinfo software version 7.1.4.0, taking into account the following parameters:
- Precision: 95%;
- Proportion of non-patients for a factor studied: 78%;
- Proportion of patients for a factor studied: 91.4%;
- Power: 80%;
- Number of controls per case: 2;
- Odds Ratio: 3.
This resulted in a minimum of 99 cases to which we added 10% margin to cover the nonrespondents and some cards with missing data that could be downgraded. Thus, after rounding, the number of expected cases was 110 cases and 220 witnesses a total size of 330 subjects.
Since this was a retrospective survey, there were no missing data because we had the possibility to automatically replace cases not found by another one.
The subjects we included in our study are those who met the following criteria:
• Case: Anyone who has had acute watery diarrhea admitted to the Kenya Cholera Treatment Center during the study period, resident of the Kampemba Health Zone and having signed their participation agreement.
• Witnesses: Any person of the same sex whose age difference with the case does not exceed five years, living in the same house or parcel, either the neighboring parcel or on the same avenue, with no history of cholera or diarrhea from the beginning to the end of the epidemic and who voluntarily agreed to participate in the study.
Data Collection Material and ProcedureDuring the preparatory phase, we proceeded by training investigators and supervisors. Aside from these, two Social Mobilizers from the Health Zone who are in charge of the disinfection of the homes of cholera patients were also recruited and made it possible to find the residences of the cases with less difficulty. A pre-test of the questionnaire was carried out in the Kenya Health Zone which presents the same context as that of the Kampemba Health Zone. This pretest enabled us to correct the weaknesses noted and to adapt the questionnaire. During the actual survey, the data were collected by interview based on this structured questionnaire which was administered at home to both cases and witnesses. The observation was made for certain variables such as the presence of the device of wash-hand and the state of the toilets. To ensure the quality of the data, supervision was provided by two people each with the responsibility of 3 investigators. In addition, each investigator marked his no on the sheet and an evaluation meeting was organized in the evening in the presence of the entire team. Which allowed us to correct in time some imperfections and inconsistencies.
The data thus collected were encoded in EPI info version 7.1.4.0 and analyzed in the same software and then exported to Excel 2013 and R software for further analysis.
Our sample consisted of a total of 330 surveyed subjects including 110 cases and 220 controls. The majority of respondents came from the Kabanga health area, 61.82%, compared to 0.91% of the Circular health area (
Out of a total of 330 people in our sample, it appears that their age ranged from 5 to 70 years with an average of 26.38 ± 15.59 years. The modal age was 10 years old.
Health Area | Frequency | Percentage | ||
---|---|---|---|---|
Case | Control | Total | ||
Circulaire | 1 | 2 | 3 | 0.91 |
Emmaüs | 4 | 8 | 12 | 3.64 |
Kabanga | 68 | 136 | 204 | 61.82 |
Kabwela | 4 | 8 | 12 | 3.64 |
Kamasaka | 5 | 10 | 15 | 4.55 |
Lapofa | 5 | 10 | 15 | 4.55 |
Njanja | 2 | 4 | 6 | 1.82 |
Polyvalent | 3 | 6 | 9 | 2.73 |
Référence | 5 | 10 | 15 | 4.55 |
Safina | 3 | 6 | 9 | 2.73 |
Saint Habraham | 4 | 8 | 12 | 3.64 |
Savio | 3 | 6 | 9 | 2.73 |
Souzanela | 3 | 6 | 9 | 2.73 |
Total | 110 | 220 | 330 | 100.00 |
The household size of the respondents ranged from 1 to 23 people with an average of 7.59 ± 3.65 people. The modal size was 7 people.
As for the treatment of drinking water,
Out of 330 respondents, 322% or 97.58% had a toilet against 8% or 2.42% who did not have one (
Compared to the knowledge of hand washing times,
Water treatment | Frequency | Percentage |
---|---|---|
No | 166 | 50.30 |
Yes | 164 | 49.70 |
Total | 330 | 100.00 |
CI [1.85 - 5.96], and p value = 0.0001), contact with a cholera patient (AOR = 2.88, 95% CI [1.65 - 5.01], and p value = 0.0002) and the stay outside Lubumbashi (AOR = 4.18, its 95% CI [1.83 - 9.55], and p value = 0.0007). On the other hand, the availability of household washbasins (AOR = 0.35, its 95% CI [0.15 - 0.83]), and warming the rest of the foods before consumption (AOR = 0), 43, its 95% CI [0.25 - 0.76], and p value = 0.0033) were protective factors (
Means of water treatment practiced | Frequency | Percentage |
---|---|---|
Chemical methods | 161 | 98.17 |
Boiling | 27 | 16.46 |
Sedimentation | 0 | 0.00 |
Solar rays | 0 | 0.00 |
Filtration | 0 | 0.00 |
Toilet | Frequency | Percentage |
---|---|---|
Yes | 322 | 97.58 |
No | 8 | 2.42 |
Total | 330 | 100.00 |
Food preservation | Frequency | Percentage |
---|---|---|
Plates or covered pans | 306 | 92.73 |
Uncovered plates or pans | 89 | 26.97 |
However, monthly income and water treatment were no longer significantly associated with cholera.
Our study aimed to determine the risk factors for the cholera epidemic in the Kampemba Health Zone to help reduce the morbidity and mortality associated with this disease. Our analyses focused on data from 330 surveyed subjects, including 110 cases and 220 controls.
This study found that the average age of patients was 26.38 ± 15.59 years and the age group of 16 - 30 years had the highest proportion, 34.55% of all cases. In a 2007 study in Lubumbashi [
These findings indicate that the age of those susceptible to cholera varies from one epidemic to another and from one country to another
Variables | AOR | I.C. 95% | Coefficient | S. E. | Z-Statistic | P-value |
---|---|---|---|---|---|---|
Monthly income | 0.998 | [0.994 - 1.001] | −0.0025 | 0.0018 | −1.4213 | 0.1552 |
Water treatment (Yes/No) | 0.59 | [0.34 - 1.03] | −0.5285 | 0.2827 | −1.8696 | 0.0615 |
Availability of washbasins (Yes/No) | 0.35 | [0.15 - 0.83] | −1.0469 | 0.4376 | −2.3921 | 0.0168 |
Food preservation (Bad/Good) | 3.32 | [1.85 - 5.96] | 1.1999 | 0.2988 | 4.0156 | 0.0001 |
Consumption of raw fruits or tubers in the last 3 days (Yes/No) | 0.91 | [0.53-1.56] | −0.0981 | 0.2763 | −0.3550 | 0.7226 |
Reheating the rest of the foods before consumption (Yes/No) | 0.43 | [0.25 - 0.76] | −0.8389 | 0.2853 | −2.9407 | 0.0033 |
Contact with a Cholera patient in the last 5 days (Yes/No) | 2.88 | [1.65 - 5.01] | 1.0572 | 0.2828 | 3.7385 | 0.0002 |
Stay outside Lubumbashi in the last 5 days (Yes/No) | 4.18 | [1.83 - 9.55] | 1.4310 | 0.4209 | 3.3997 | 0.0007 |
CONSTANT | * | * | −0.4711 | 0.3751 | −1.2560 | 0.2091 |
As for gender, our study found that the female sex was more affected than the male sex (57.27% and 42.73%) with a male/female sex ratio of around 0.75. These results are similar to those of Nsagha et al. in Buea, Cameroon (57.8% for females and 42.2% for males) [
Regarding the distribution by residence, it emerges that Kabanga health area over half of cases or 61.82%. In his study on the endemic factors of cholera in Douala, Guevart et al. described the Bepanda area which was a starting point for cholera outbreaks as a slum area established on a garbage dump in an area fueled by drainage ditches carrying faecal pollution from nearby ascending areas. It is a mass sector overloaded with uncontrolled urbanization produced by the influx of poor newcomers who live there without adequate access to clean water or basic sanitation. And that, the most affected corners are those not urbanized, swampy with polluted dumps [
The majority of the population living in this health area uses water from unimproved wells for drinking. It is the very epicenter of this latest epidemic.
Regarding the treatment of water, half of the subjects surveyed (50.30%) use the treatment of drinking water while the other half do not treat it. The similar result was found in Chad where 55% of the respondents on behavioral determinants of water treatment in cholera prevention did not use water treatment [
In the bivariate analysis, the following factors were identified as significantly associated with cholera: low monthly income (Mann-Whitney/wilcoxon chi-square = 5.73 and p = 0.0167); treatment of drinking water (OR = 2.26, its 95% CI [1.41 - 3.62], and p value = 0.0006), non-availability of washbasins in the household (OR = 2.46, 95% CI [1.50 - 4.02], and p value = 0.0003), poor food preservation (OR = 4.60, 95% CI [2.75 - 7.69], and p value < 10-10), the non-reheating of food residues before consumption (OR = 2.65, its 95% CI [1.36 - 5.17]; value = 0.0037) and contact with a cholera patient in the 5 days preceding the disease (OR = 3.96, 95% CI [2.42 - 6.49], and p-value < 10-10). However, as with the study conducted in Papua, Guinea [
The level of study was not significantly associated with the disease; and between employment (occupation) and illness. These same results have been found elsewhere [
A significant association with drinking water quality was not demonstrated in this study (OR = 0.88, 95% CI [0.54 - 1.44], and p-value = 0.6161). More than half of the subjects surveyed (68.18%) did not have access to drinking water, including 69.09% among controls and 66.36% among patients. This would be within certain limits of this study with bacteriological analyzes of drinking water to provide evidence for the role of water in cholera transmission. However, some authors have shown that the poor quality of drinking water is associated with the increased risk of cholera [
After multivariate analysis using logistic regression to identify risk factors for cholera taking into account the interactions of each other, the following results were obtained:
Regarding the non-selected factors, we note the monthly income which, during the bivariate analysis, showed that the monthly income was significantly lower in the cases than in the controls (chi-two of Mann-Whitney/wilcoxon = 5.73 and p = 0.0167). The regression showed that monthly income did not increase the risk of contracting cholera (AOR = 0.998, 95% CI: [0.994 - 1.001], p-value = 0.152). In bivariate analysis, the average monthly income for cases was 146.23 ± 78.96 USD. On the other hand among the witnesses, it is of the order of 170.53 ± 91.89 USD. These results corroborate with a study that was conducted in 2009 from data obtained from WHO reports and from the classification of the World Bank of countries engaged in their income. This study shows that low-income countries are more affected by cholera than those with medium or high incomes. This supports the phrase “cholera is a disease of poverty” [
In addition, non-treatment of drinking water was identified as a factor that had twice the risk of cholera occurrence in bivariate analysis (OR = 2.26, 95% CI [1.41 - 3.62] and p value = 0.0006), is also considered not significant after multivariate analysis (AOR = 0.59, 95% CI: [0.34 - 1.03], p-value = 0, 0.615). Some authors had achieved the same results as those found during the bivariate analyzes. This is the case of TUBAYA, which found a nine-fold higher risk in subjects consuming untreated water (OR = 8.6, 95% CI: [4.58 - 16.4]) [
As for the factors significantly associated with cholera that were retained, we note:
Poor food preservation (AOR = 3.32, 95% CI [1.85 - 5.96], and p-value = 0.0001); about one out of every two patients had poor food (in open plates or pots) against one out of six witnesses. This exposes food to flies in a polluted environment. Added to this is the poor quality of well water used by most households for washing utensils. Recent studies have shown that V. Cholerae can remain for more than 5 days in the digestive tract of houseflies and multiply there; which gives evidence in the role played by the latter in the transmission of the disease [
Regarding contact with a cholera patient in the previous 5 days. This factor was considered significantly associated with cholera risk in both bivariate and multivariate analysis (AOR = 2.88, 95% CI [1.65 - 5.01], and p value = 0.0002). Indeed, more than half of the patients reported having been in contact with a cholera patient in the 5 days preceding the illness against 21.36% of the controls. The habits of the environment, which make the family members take care of the patient, rid him of these excretions from the house to the center of the treatment of cholera, a way to show him their love and compassion; in a context where almost half of the population is unaware of early signs and cholera prevention measures [
Many studies carried out and epidemics investigated throughout the world by some authors have resulted in the same results. This is the case of TUBAYA in Lubumbashi (OR = 93.43, 95% CI: [53.77 - 164.07] [
Regarding the notion of travel, having stayed outside the city of Lubumbashi in the last 5 days before the onset of the disease had four times the risk of contracting cholera (AOR = 4.18; its 95% CI [1.83 - 9.55] and p value = 0.0007); nevertheless, during the bivariate analysis, this factor was not significant but nevertheless had a p < 0.20 which allowed us to integrate it into the multivariate analysis, the weight of its risk being masked by interactions with the other factors. This situation could be explained by the fact that the patients had stayed outside the city of Lubumbashi more than witnesses, i.e. 17.27% against 11.36%. Indeed, the city of Lubumbashi is surrounded by several other cities that are endemic and/or epidemic cholera, which are in intense trade facilitating the importation of epidemics of cholera. In addition, poor travel conditions do not take into account the basic principles of hygiene. Similar results were recorded during the investigation of an outbreak in Alborz Province, Iran, while taking into account the same 5-day delay (OR = 5.21, 95% CI: 2.21 - 9.72) [
The availability of hand washing in households provides protection against the occurrence of cholera (AOR = 0.35, its 95% CI [0.15 - 0.83], and p-value = 0.0168). In other words, the subjects that result indicate that the witnesses had more washbasins than the patients. Bivariate analyzes had shown that the risk of contracting cholera was about twice as high for people without washbasins than for those who did (OR = 2.46, 95% CI [1.50 - 4.02] and p value = 0.0003). For UNICEF, the washbasin motivates and facilitates the practice of handwashing in the household, necessary for the prevention and control of cholera [
Warming up the rest of the foods before they were consumed was a protective factor against the occurrence of cholera (AOR = 0.43, 95% CI [0.25 - 0.76], and p-value = 0.0033). Indeed more than three quarters of the witnesses warmed the food before its consumption against about half of the patients. In other words, people who did not warm up food leftovers prior to their consumption had an increased risk of contracting cholera. A study in Katanga reported that only 61% of those surveyed knew that cholera could be transmitted through food [
Cholera, a very old disease, remains as a public health problem in the Kampemba Health Zone. Our study set itself the goal of identifying the risk factors for the cholera epidemic in order to contribute to the reduction of morbidity and mortality related to this disease in this Health Zone.
At the end of this study, the following results were observed with regard to socio-demographic and economic characteristics: the average age was 26.38 ± 15.59 years ranging from 5 to 70 years, the female sex was the most affected i.e. 57.27%, 61.82% of the subjects came from of the Kabanga health area and about half of the subjects were single (50.30%). The majority had a low standard of living (64.85%) and were unemployed (60.00%) although they had a secondary level of education and more in 94.55% of cases.
As for hygiene conditions, 31.82% had access to drinking water, only one out of two subjects resorted to the treatment of water and that by chemical methods (98.17%). A good proportion of respondents had a toilet (97.58%) of which 36.96% were hygienic. Handwashing devices were available in only 16.97% of households and 27.27% did not retain food.
After multivariate analysis, the following factors were significantly associated with cholera: poor food preservation (AOR = 3.32, 95% CI [1.85 - 5.96]), contact with a patient with cholera in the 5 days preceding the disease (AOR = 2.88, its 95% CI [1.65 - 5.01]) and the stay outside the city of Lubumbashi in the last 5 days preceding the disease (AOR = 4.18, 95% CI [1.83 - 9.55]). In addition, the availability of household washbasins (AOR = 0.35, its 95% CI [0.15 - 0.83]), and warming the food remains before consumption (AOR = 0.43, its 95% CI [0.25 - 0.76]) were protective factors.
However, this study did not demonstrate a significant association between the quality of drinking water and the occurrence of cholera. The usual health communication channels were used (radio broadcasts, posters...) without the cholera being eradicated; however, some local channels such as churches, mosques, trade union movement, political parties and community health workers (as an organ community participation) can be privileged.
Benjamin, K.I., Simon, I.K., Luvungu, N., France, B.M., Gladys, K.L., Raphaël, M.I., Justin, M., Pascal, K.M., Charles, M.M. and Ghislain, M.N. (2018) The Recurrence of Cholera in the City of Lubumbashi: Investigation of Risk Factors for an Effective Response and Health Education Perspective. Open Access Library Journal, 5: e4554. https://doi.org/10.4236/oalib.1104554