Cholera Epidemiology and Response Factsheet Cameroon
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CHOLERA EPIDEMIOLOGY AND RESPONSE FACTSHEET CAMEROON Figure 1. Yearly number of cholera cases and case fatality rate (CFR) in CHOLERA OVERVIEW Cameroon, 1990–20131 Cholera was first reported in Cameroon in 1971. Since 1990, there have been large outbreaks in 1991, 1996, 1998, 2004, 2010 and 2011. The overall yearly trend shows an increase in size over time (Fig. 1). Between 2004 and 2013, epidemiological surveillance reported 46,172 cases with 1,817 fatalities (high case fatality rate ≈ 3.9%)1. Main outbreaks were reported in the north in Far North and North Case fatality rate Number of cases regions and in the south of the country in the Littoral region which hosts the economic capital Douala (Fig. 2 and Tab. I). The country is affected by cross-border outbreaks, especially along its borders with Chad and Nigeria. CHOLERA DISTRIBUTION Figure 2. Cumulative incidence of cholera by region in Cameroon, 2004–20132 In the north of Cameroon, the regions of North and Far North reported 47.3% of cholera cases between 2004 and 2013. The average CFR is high (≈ 8%), explained in part by poor access to health facilities and a high number of community deaths (Tab I.). In the south of Cameroon, the region of Littoral reported almost one third (29.6%) of cases, mainly in the city of Douala. In addition, the nearby region of Southwest at the border with Nigeria reported approxi- mately 8% of cases (Tab I.). The region of Centre containing Yaoundé reported less cases than Douala but more frequently, with cases reported in six years out of ten. There are two different seasonal patterns of outbreaks in Cameroon. In the north, outbreaks occur in May/June (week 23–26). There is an increase of the number of cases reported during the rainy season between June and October and a sharp decrease from mid-November (Fig. 3). In the South, outbreaks occur at the end of the dry season around January/February. The number of cases usually increases from February to March5,6. The recent increase of the size of outbreaks can be explained in part by a reduced sensitivity to ciprofloxacin inVibrio cholerae O1 strains and the presence of atypical cholera toxin B (ctxB) genotype7. Table I. Epidemiological parameters of cholera outbreaks by main affected region in Cameroon, 2004–20132 % of Number of Region Cases / Deaths [1] total Duration [2] outbreaks cases Figure 3. Weekly number of cholera cases and median of estimated ten-day precipitation in Far North Cameroon, 2004–20132,3 Far North 16,457 / 979 35.1 4 20 Littoral 13,886 / 766 29.6 4 20 North 5,744 / 335 12.2 2 37 South West 3,829 / 70 8.2 2 31 Center 3,669 / 166 7. 8 6 15 West 2,526 / 86 5.4 2 26 South 414 / 14 0.9 3 7 Adamaoua 205 / 19 0.4 1 25 North West 144 / 11 0.3 1 12 East 50 / 7 0.1 1 13 Note. [1] Total of cases = 46,924 and deaths = 2,453 between 2004 and 2013; [2] Average number of weeks between 2010-2013. Choléra Epidémiologie et Réponse Factsheet CAMEROUN STRATEGIC RECOMMENDATIONS Figure 4. Water and sanitation coverage estimates in Cameroon, 1990–20124 Outbreak onset and cross-border spread frequently occur in the regions of Far North, North, Southwest and Littoral (Douala). High-risk cholera regions are located on a corridor where outbreaks spread from and to neighbouring countries, mainly Nigeria and Chad, highlighting the impor- tance of cross-border activities8 (Fig. 2). In those regions, preparedness and response plans should be developed and implemented including: (1) strengthening early detection and rapid response systems of which community based surveillance and cross-border alert; (2) setting up coor- dination mechanisms across the sectors and borders; (3) building capacity on outbreak management; (4) targeted pre-positioning of supplies and (5) preparing communications messages and plans. Because of the high CFR, training on outbreak management and pre-positioning of supplies are highly recommended, especially in the Far North region. Livelihood groups and high risk practices to be considered in preven- Far North Cameroon tion, preparedness and response strategies8,10: Overall, districts regularly affected and with a medium to high duration or incidence are located in the main city (Maroua) and surrounding districts, • Cross-border markets, funeral rituals, patient care at home and home around the Lake Chad (Mora, Mada, Kousseri), along the Logone River at visits (regions of North and Far North); the border with Chad (Maga, Guere, Vele, Yagoua, Moutourwa) and at the • Formal and informal trade and nomadic communities along the Lake border with Nigeria (Kolofata, Mogode, Bourha, Hina, Tokombere) (Tab. II). shores (Mora, Mada, Kousseri, Makari, Goulfey); • Migrant fishermen communities in the Lake Chad shores, along the Logone River (border with Chad) and on islands in front of Douala Sustainable Water, Sanitation and Hygiene activities should be a priority (communities from Nigeria, Togo, Benin and Ghana); in districts regularly affected and with long outbreaks (Tab. II, Type 1). • Densely overcrowded areas in Douala city (ex: Bepanda slum) without A WASH and epidemiological study conducted in 2010 in the four Lake adequate access to clean water or basic sanitary facilities. Chad basin countries has shown that the use of water from open wells in the regions of North, Far North and Adamawa was associated with cholera outbreak notification8. The study recommends the replacement of open wells by boreholes or protected wells and the development of a Way forward household water treatment method and the scaling up of Community-Led Additional epidemiological data and analysis are needed to identify cholera Total Sanitation in priority rural intervention areas. An anthropological study hotspot(s) in the regions of North, Southwest and around Douala city. conducted in 2011 at the Chad-Cameroon border in the north part of the Furthermore, a multidisciplinary study should be conducted to identify country gives elements of the perception of cholera and control activities long-term programmatic responses in rural and urban context in priority by the population and the local authorities and helps refining the ways of intervention areas. intervention of governments and agencies9. Table II. Summary of cholera hotspots classification and strategic interventions in Far North Cameroon, 2004–20132 - - DISTRICT Early ment lance Study spread Role of Role duration Outbreak Outbreak Recurrence Emergence vaccination WASH-Epid. WASH-Epid. Cross-border Cross-border Cross-border collaboration Hotspot type (median onset Preaparadness Mean incidence WASH develop WASH week [min–max]) per 10,000 inhab.) (No. of outbreaks) ( (average in weeks) detection Surveil MADA 6 18 21 26 [17–33] Yes T. 1 √ √ √ √ √ √ KOUSSERI 4 25 17 22 [12–33] Yes T. 1 √ √ √ √ √ √ MAGA 3 19 16 30 [23–30] Yes T. 1 √ √ √ √ √ √ MORA 3 15 10 31 [30–37] Yes T. 1 √ √ √ √ √ √ GUERE 2 31 47 17 [13–21] Yes T. 2 √ √ √ √ √ √ HINA 2 13 5 33 [26–40] No T. 2 √ √ √ √ √ MAROUA RURAL 2 16 4 29 [29–30] No T. 2 √ √ √ √ √ MAROUA URBAIN 2 17 29 30 [30–30] No T. 2 √ √ √ √ √ VELE 2 18 19 30 [23–37] Yes T. 2 √ √ √ √ √ √ YAGOUA 2 20 6 26 [23–29] Yes T. 2 √ √ √ √ √ √ KOLOFATA 5 9 9 34 [25–37] Yes T. 3 √ √ √ MOGODE 3 12 8 30 [20–37] Yes T. 3 √ √ √ BOURHA 2 9 6 34 [33–35] No T. 4 √ √ MOUTOURWA 2 9 8 36 [30–42] No T. 4 √ √ TOKOMBERE 2 12 13 30 [30–31] No T. 4 √ √ Note. Type 1 (T.1): High priority area with a high frequency (>80th percentile) and a long duration (>40th percentile). Type 2 (T.2): Medium priority area with a moderate frequency (between 60th–80th percentile) and a long duration (>40th percentile). Type 3 (T.3): Medium priority area with a high frequency, a short duration (<40th percentile) and a high incidence (>40th percentile). Type 4 (T.4): Low priority area with a moderate frequency, a short duration and a high greeneyezdesign.com Artwork by incidence. References Acknowledgements 1. Global Health Atlas, WHO: http://apps.who.int/globalatlas. 6. Garrigue E, Weather and cholera: epidemic in Douala, Cameroon Djao R. and Ndong Ngoe C., MD, Ministry of Health Cameroon, Dunoyer 2. Ministry of health Cameroon, 1994–2013 cholera data. in 2004, Med Trop (Mars). 2010 Aug; 70(4):407–8. J. (coordination, UNICEF WCARO), Sudre B., MD PHD (scientific advice), 3. FEWSNET (Famine Early Warning Systems Network: 7. Quilici ML, Vibrio cholerae O1 Variant with Reduced Susceptibility Green HK., PHD (data analysis), Rossi M. (spatial data management). http://www.fews.net/ ). to Ciprofloxacin, Western Africa, Emerg Infect Dis. 2010 Nov; 16(11): 4. Multiple Indicator Cluster Surveys (MICS) and Demographic and 1804–1805. Health Surveys (DHS), 2012: http://data.unicef.org/water-sanitation/ 8. Oger P.-Y. , Sudre, B., 2011. Water, Sanitation and Hygiene and Cholera sanitation. Epidemiology: An Integrated Evaluation in the countries of the Lake 5. Garrigue E, Antibiotic resistance of strains of Vibrio cholerae el tor Chad Basin. UNICEF. isolated in Douala (Cameroon), Bull Soc Pathol Exot Filiales. 1986; 9. Kouokam Magne, E., 2011. Anthropology of cholera transmission 79(3):305–12. modes at the Chad-Cameroon border. 10. Garrigue E, Factors contributing to endemic cholera in Douala, Cameroon, Med Trop (Mars). 2006 Jun; 66(3):283–91. .