Abstract
Introduction
Dysentery is an infectious clinical syndrome which can cause high morbidity and mortality, especially in developing countries. This research highlights the epidemiological features of dysentery in Lemghaier province, Algeria.
Methods
A retrospective study of the incidence rates of dysentery in Lemghaier province, Algeria and overall for the whole country for the period from January 2001 to December 2018 was carried out. On a local level data were provided by the Directorate of Health and Population of El-Oued province, Algeria. At the national level data were provided by the National Public Health Institute, Algeria.
Results
An overall number of 1,786 cases of dysentery were notified, with an incidence rate of 58.5 cases per 100,000 population (mean±SD: 58.54±47.20; 95% CI: 36.73-80.35). The high incidence rate was reported in autumn and summer, respectively, with 23.4 and 20.1 cases per 100,000 population. The high incidence rate observed in the persons aged 20–44 years with 76.4 cases per 100,000 population. Females were more likely to have dysentery than males, respectively, with 63.6 against 53.7 cases per 100,000 population. The highest incidence rate was reported in Lemghaier municipality (capital of the province) with 176.9 cases per 100,000 population.
Conclusions
The results from this research showed high incidence rates of dysentery in Lemghaier province, Algeria. Тhis fact is a serious reason for national public health organizations to take adequate and timely measures to reduce the incidence rates of dysentery in this part of the country.
Keywords: Algeria, dysentery, incidence rate, Lemghaier province
Introduction
Shigellosis is an infectious disease which is caused by the bacteria Shigella. Most patients with shigellosis have diarrhea, fever, and stomach cramps. Shigella cause an estimated 450,000 cases in the USA each year.1 Shigella is a Gram-negative, non-motile bacillus belonging to the Enterobacteriaceae family. Until now, from the scientific literature four species of Shigella are known: Shigella boydii, Shigella dysenteriae, Shigella flexneri, and Shigella sonnei.2 While S. boydii and S. sonnei most often generate a relatively mild clinical form of disease (watery or bloody diarrhea only), S. flexneri and S. dysenteriae are mostly responsible for shigellosis endemic and epidemic in developing countries, which associates high transmission rates and important case fatality rates (CFR).
The severe clinical form of shigellosis is known as dysentery. Dysentery can occur through the oral uptake of the pathogen via contaminated water or food, also from poor personal hygiene when coming in contact with infectious material or infected persons.3 Dysentery remains a serious public health problem worldwide, especially in developing countries. Annually, more than 165 million cases of dysentery are reported worldwide, of which 1.1 million deaths, with approximately 99% of cases occurring in developing countries.4 Besides, about 50 million confirmed cases annually are notified related to the other infection causing dysentery – amebiasis (Entamoeba histolytica infection), of which 40,000 to 110,000 death cases.4
The study of Ferrer et al. concluded that the socioeconomic factors followed by interpersonal contact were the most important drivers of dysentery occurrence, while factors regarding food preparation, the environment and the water, along with sanitation, played a secondary role.5 Although many studies focus on sanitary and water supply as traditional factors of the dysentery incidence rate, some modern research in this field demonstrated that human behaviors have a considerable proportion in determining the incidence of this disease, and may sometimes outweigh the effect of the traditional factors.6,7
Dysentery control includes improved personal hygiene and avoiding contamination of food and water with infected feces. A survey carried out in the Volta region, Ghana, found that dysentery incidence can be reduced by 11% in children under 5 years if a clean water source is guaranteed.8 Homemakers can play an essential role in limiting dysentery by providing a safe house environment to their families, especially children. In this regard, an educative and awareness program can play an active role in this process.
In Algeria, the Ministry of Health and Population classed dysentery among obligatory notifiable diseases. From 2001 to 2018, the national public health institute reported more than 16,300 confirmed dysentery cases. The aim of the present study was to highlight the epidemiological features of dysentery in Lemghaier province, Algeria. Until now, such a survey has not been conducted for this part of the country.
Methods
Dysentery is characterized by frequent small bowel movements accompanied by blood and mucus, with tenesmus or pain on defecation.9 This clinical syndrome (with fever or without fever) implies an inflammatory invasion of the colonic mucosa resulting from cytotoxic, parasitic or bacterial destruction.9 This survey has basically epidemiological characteristics because of which no data were collected for the main etiological reasons (pathogens) for dysentery.
A retrospective study of the incidence rates of dysentery in Lemghaier province, Algeria and overall for the whole country for the period from January 2001 to December 2018 was carried out. On a local level data were provided by the Directorate of Health and Population of El-Oued province, Algeria. At the national level data were provided by the National Public Health Institute, Algeria. The dysentery data include year and month distribution; municipality incidence rate; patient’s gender and age group. In addition, the Directorate of Water Resources, El-Oued province, Algeria provided us the data concerning the percentages of homes connecting with drinking water and the sewerage networks. The incidence was calculated as the number of cases per 100,000 population corresponding to each year, municipality, gender, and age group.
The Republic of Algeria is divided into 58 provinces. Lemghaier province is a group of oases locates in the Northeastern Algerian Sahara (Figure 1). This province locates approximately on 5°11′ E and 6°09′ E longitude; 33°25' N and 34°30' N latitude. The elevation decreases from the Southwest in the Marrara municipality (225 m) to the Northeast in Chott Merouane (–27 m). In the past, the research area administratively belonged to El-Oued province. However, the new administrative division for the year 2019 separated this region to become a province alone. This new province includes eight municipalities and occupies an area of 8,835 km2, and also, it counted about 231,000 population in 2018. The climate is typically Saharan, with a dry period extending throughout the year. January is the coldest month, and the warmest month is July, where temperatures can reach 45.0°C. The annual mean of temperature is around 25.0°C.
Figure 1. Geographical location of Lemghaier province, Algeria.
In the present study we applied descriptive statistical analysis (percentages, confidence intervals, standard deviations, box plots, etc.). Statistical analysis was performed by MS Excel 2007 (USA) and IBM SPSS Statistics version 20.0 (USA). A p value <0.05 was considered statistically significant.
The present research was performed in accordance with the ethical principles of the Declaration of Helsinki (June 1964; last revision in October 2013). The information and documents were processed and protected according to national legislation of Republic of Algeria. The information included in this survey is public and does not contain state secrets or other data connected with national security on the country.
Results
A total of 1,786 confirmed cases of dysentery were notified in Lemghaier province, Algeria, from January 2001 to December 2018. The annual overall number of cases ranged between 8 and 244, with mean of 99.2 cases per year (95% CI: 62.14-136.29). The highest incidence rate was reported in 2011, with 138.5 cases per 100,000 population, followed by 2007 with 137.6. On the other hand, the lowest incidence rate was notified in 2013 and 2012, respectively 4.3 and 4.4 cases per 100,000 population. The mean of the period was 58.5 cases per 100,000 population (mean±SD: 58.54±47.20; 95% CI: 36.73-80.35). Thus, starting 2012, the incidence rate of dysentery has undergone an evident decrease compared to the first part of the research period (Figure 2). At the national level, the results show that the incidence rate values ranged between 0.40 per 100,000 population (2012) and 9.17 (2001), while the national mean of dysentery incidence was estimated at 2.75 (95% CI: 1.54-3.95) (Figure 3).
Figure 2. Annual distribution of dysentery incidence rate in Lemghaier province and at national level (2001-2018).
Figure 3. Annual development of dysentery incidence rate in Lemghaier province according to drinking water and wastewater networks connection (2001-2018).
The monthly distribution of dysentery has a seasonal trait (Figure 4). The dysentery incidence rate increased as follows: winter – 2.9 cases per 100,000 population; spring – 12.1; summer – 20.1; and autumn – 23.4. The monthly mean is estimated at mean±SD 14.62±7.91 cases per 100,000 population (95% CI: 6.86-22.38). At the national level, dysentery incidence increases as follows: winter – 0.45 cases per 100,000 population; spring and summer – 0.67; and autumn – 0.95. The monthly mean is estimated at mean±SD: 0.68±0.17 cases per 100,000 population (95% CI: 0.51–0.85). A powerful and positive correlation was noted between these two seasonal distributions, in which the correlation coefficient reached 0.90.
Figure 4. Seasonal distribution of dysentery incidence rate in survey area.
Dysentery occurs in all age groups (Figure 5). However, a high incidence rate was observed in the persons aged 20-44 years, with 76.4 cases per 100,000 population, followed by children less than 9 years with 70.2. In other age groups, the incidence ranges between 26.4 (≥65 years) and 35.9 (10-19 years) cases per 100,000 population. Besides, females are more exposed to have dysentery than males, respectively with 63.6 versus 53.7 cases per 100,000 population.
Figure 5. Incidence rates of dysentery in study province according to gender and age group.
All municipalities have been affected by dysentery. The highest incidence rate was reported in the capital of the research province, Lemghaier municipality – 176.9 cases per 100,000 population (about 93.5% of total reported cases). In the Still, Sidi Khalil and Oum Tiour municipalities, the incidence rate range between 13.1 and 28.8 cases per 100,000 population. In the remaining municipalities, the dysentery incidence rates are characterized by low values – between 0.6 and 2.3 cases per 100,000 population.
Discussion
The annual reports of the National Institute of Public Health, Algeria show that dysentery is widespread throughout the country. Furthermore, Southern Algerian provinces are more threatened by dysentery than the Northern part of the country.10 This survey consists of a retrospective analysis of dysentery cases reported in Lemghaier province, Algeria. In fact, we can say that the actual number of dysentery cases is higher than what was reported in the official registers of health authorities. For example, some private physicians do not report dysentery cases discovered in their private practices. However, dysentery is listed among obligate reportable diseases by the health Algerian ministry.
Generally, many geographic, socioeconomic, environmental, and behavioral factors effectively contributed to large dysentery outbreaks, making Lemghaier province a critical focus for this epidemic for a long time. For example, low-income families often store water in traditional utensils placed in toilets to avoid disrupting the drinking water supply, which leads to contamination with various pathogens. A study by Khezzani and Bouchemal confirms that this behavior led to typhoid fever speared in the Souf oasis, Algeria.11
We can note that the situation of dysentery in the survey area is very complicated compared to the overall situation in the country. In the 1980s, the incidence rate has reached 65 cases per 100,000 population at the national level. So, this situation suggests the dysentery incidence rate in the Lemghaier province may have been in the range of 1,000 to 1,300 cases per 100,000 population in that period. Whether at the national or local level, the annually decreasing trend of dysentery incidence translates the Algerian health authorities' considerable efforts in combating water-borne diseases, especially dysentery.
During the period covered by the current research, the Directorate of Water Resources in Lemghaier province improved the service of connection to the water supply network, as the percentage of housing connected to this network increased from 73.3% in 2001 to reach 97.6% in 2018. In the same context, the National Sanitation Office improved the sanitation service, where the connection rate with this network reached 91.9% in 2018 after it was around 67.4% in 2001. On the other point of view, the decreasing curve of dysentery may be due to the rapid development of the economy and improved public health facilities at local and national levels.
Some studies indicate that the dysentery incidence rate is very sensitive to changed climate factors (between individual years).12 Thus, this effect can explain to some extent the fluctuation noted in the yearly distribution of dysentery, of course, taking into account the rest of the other factors affecting it.
Dysentery pathogenesis is very sensitive to seasonal changes in climatic factors.13 Thence, the incidence peak noted in some months could be linked to seasonal activities leading to a close relationship between human and infection sources. Therefore, the high incidence rate noted in the autumn and summer seasons can probably be explained by the interaction between climatic and socioeconomic factors and the biological features of the causative agents of dysentery. In the survey area, the autumn season (September and October) coincides with the spreading peak of house flies Musca domestica. According to Nazari et al., Musca domestica play an essential role in transmitting many disease causative agents, especially those that cause dysentery.14 Greenberg mentioned some examples from different world regions, where he confirmed that the dysentery's spread peak always coincides with the height of the Musca domestica spread peak.15 Besides, the study by Farag et al. in Mirzapur, Bangladesh, shows a positive correlation between Musca domestica population density and shigellosis incidence.16 Besides, cockroaches Blattella germanica (abundant in the study country) can be a vector of many intestinal parasitic protozoa, especially Entamoeba histolytica.13,17,18
Some behavioral actions have a relationship to the spread on dysentery. During autumn is the season to collect fruits of the palm groves in Lemghaier province. In this regard, during this activity many of the citizens of the province often defecate indiscriminately in the bushes and nearby agricultural canal drain. Additionally, in this activity people eat their food on the floor and use irrigation water for washing (hands, vegetables, cooking utensils). These conditions increase the risk of dysentery incidence.
Furthermore, the rise in dysentery incidence rate at the beginning of September might be due to the children and students returning to the schools and universities after their summer holidays and the influx of new children to kindergartens. These findings were consistent with those of Sultanov in Dagestan, Russian Federation.19
Geographic location could play an essential role in the dysentery outbreak. The survey area contains many wetlands, which according to Jorgensen et al., is a factor more favorable to the occurrence of various water-borne diseases.20 Many prior scientific publications support this view, especially Ni et al. in Xinxiang city, China, which found a positive correlation between flood sand and increased dysentery risk.21
Generally, all age groups and both genders are susceptible to dysentery.4 However, the high incidence rate noted among the female category compared to the male category is not due to the nature of the patient's biological characteristics, but it can be linked to the nature of the daily activities practiced. Most likely, males have more opportunities to be exposed to environments containing the pathogen.22 At the same time, women's contribution cannot be ignored in rural communities to manage various agricultural activities in some regions and some periods. This increases the risks for infection of the female sex.
The web of determinants for dysentery in children is complex. However, children under 5 years of age have been reported to be susceptible to dysentery because of a decreased immune function, combined with lack of previous exposure, and a higher likelihood of exposure to a pathogen in the contaminated environment through play-related activities.23 Recent studies indicate that dysentery is the primary killer of children under 5 years, accounting for 9.2% of total child deaths.8 For example, dysentery is responsible for 15% of all deaths in children under 5 years and is the third leading cause of childhood deaths in Mbour, Senegal.24 Furthermore, Tulu et al. found that parents with a high educational level can provide better sanitation conditions for their children than those with a low educational level.25
A potential cause for the higher number of registered cases of dysentery in Lemghaier province can be increased reporting due to the interest of public health specialists about this clinical syndrome. Essentially this is a hypothesis which can be object of future research.
The current research has some limitations that need to be addressed. Our data series does not contain any details related to the species of pathogen that led to dysentery. Furthermore, the present survey included one province out of a total of 58 provinces in the country, so it was not a nationwide survey. Despite these limitations, this work represents the first study on the dysentery incidence rate among humans in this part of Algeria, enriching the knowledge on this infection for Northern Africa.
Conclusions
We have presented the first report on incidence rates of dysentery among humans in Lemghaier province, Algeria. The situation of the dysentery in this part of the country is alarming, so it must be remedied as soon as possible. Besides the environmental factors, humans have a significant part of the dysentery outbreak's responsibility. In this regard, we recommend adopting educational programs and campaigns to raise awareness, especially among at risk groups. Furthermore, the inclusion of programs related to public health subjects and disease prevention within the educational system will constitute a solid base that can be relied upon in the future in fighting infectious and dangerous diseases.
Footnotes
Authors’ contributions statement: BK contributed to study design, data collection, data interpretation, statistical analysis, article preparation, and literature search. MB contributed to study design, data interpretation, statistical analysis, article preparation, and literature search. EAK, KG, ZM, and ABB contributed to data collection and literature search. All authors read and approved the final version of the manuscript.
Conflicts of interest: All authors – none to declare.
Funding: None to declare.
Acknowledgment: The authors would like to thank all Public Health specialists who helped complete this research, especially Mr. Mohammed Rahal from El-Oued University and Dr. Said Adouka from the Directorate of Health and Population, El-Oued province.
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