Cameroon first reported cholera to the WHO in 1970, with more than 2,000 cases. Until 1985, only sporadic cases were reported, but over the past years Cameroon has been afflicted by recurrent epidemics, with as many as 9,154 cases reported in December 2010. From January to April 2011, the number of cases reported nationwide was more than 3000 with 136 deaths. Most cases this year have occurred in the central region, in addition to the coastal and south-western regions.
As elsewhere in Africa, the case fatality rate (CFR) has drastically decreased since the first reported epidemics. As high as 15%, 9%, 12% and 8.3% during the 1970, 1985, 1991 and 1996 epidemics, respectively, the CFR was of 6.25% and 4.5% during the latest 2010 and 2011 outbreaks, respectively.
Cameroon hosts two National Reference Laboratories (NRL) for cholera, both belonging to the network of the Pasteur Institutes: the Centre Pasteur Cameroun (CPC) in Yaoundé is the NRL for all southern health regions, and the Centre Pasteur Antenne de Garoua is the NRL for the northern health regions. Both NRL diagnose cholera cases by conventional bacteriological techniques from stool cultures and determine the antibiotic susceptibility and serotype of each identified strain of Vibrio cholerae, according to the protocol of the National Reference Centre of the Pasteur Institute in Paris. CPC also performs cholera diagnosis by molecular biology.
Democratic Republic of Congo (DRC)
The first cases of cholera were reported in the DRC in 1974, and since the late 1990s, the DRC has been among the five countries in the world the most affected by cholera. From 2001 to 2009, 213,377 cases and 6,319 related deaths were reported in the country, with an attack rate of 36 cases per 100,000 and a lethality rate of 2.85%. The provinces most affected by cholera are the eastern ones with 47.3 cases per 100,000 inhabitants, and a maximum of 93.1 cases per 100,000 people. To the west of the DRC, the incidence varies between 0.5 and 1.4 cases per 100,000 inhabitants. In the lake areas, cholera has a seasonal pattern, with the incidence peaking during the rainy season.
The Ministry of Public Health is the main actor in the fight against cholera. Cholera surveillance is conducted by the Direction de la Lutte contre la Maladie (DLM), the Institut de Recherche Biomédicale, and the provincial health inspections, health areas and their treatment centers. The coordinating structure is the Comité Intersectoriel de Lutte contre le Choléra (CILC) that brings together national and international partners.
Guinea has experienced cholera epidemics since 1970. According to the Ministry of Health, about 60,000 cases and 2,276 deaths from cholera have been reported since 1970. The frequency of outbreaks has increased in Guinea-Conakry over the last two decades, reaching a yearly occurrence between 2003 and 2007.
The major 1994 outbreak accounted for 31,415 cases and 671 deaths within the city of Conakry alone. From 1998 to 2009, the annual number of cases in Guinea varied from six (2003) to 8,500 (2007). Vibrio cholerae serogroup O1 biotype El Tor was the causative agent of all these outbreaks. According to the WHO, Guinea reported 19,257 cases and 880 deaths between 1999 and 2009.
Before 1994, outbreaks in the country remained limited to the coastal strip and the capital, with the first cases appeared in people living in the coastal lagoon near the border with Sierra Leone. Starting with the Conakry 1994 epidemic, cholera spread to even the most remote prefectures in the country.
Cholera lethality ranged from 3.6% in 2007 to 8.6% in 2006. In 2008, Guinea reported 32 deaths out of the 513 cholera cases, leading to a CFR of 6.24%, the fourth highest CFR reported by countries worldwide that year.
A study on data from 2003-2007 (UNICEF, 2009) described a link between the rainy season and the resurgence of cholera outbreaks, with a seasonal increased risk from April to June.
In Guinea, cholera surveillance was part of the “Surveillance Intégrée de la Maladies et la Riposte” (SIMR), and was a systematic collection, analysis and data interpretation of morbidity and mortality of disease. Data was collected in health facilities and sent weekly to cholera surveillance focal points in eight regions. The Prefectural Health Directorate compiled the data and forwarded it to the Regional Health Directorate, which summarized and transmitted it to the “Direction de la Lutte contre la Maladie” at the Ministry of Health. In case of an outbreak, a national crisis committee, chaired by the Minister of Health, met once a week for an update on the epidemiological situation.
Since 1971, Kenya has suffered several cholera epidemics and has reported cases every year from 1974 to 1989. The largest epidemic started in 1997 and lasted until 1999, with more than 33,400 reported cases. The 1997 outbreak started in June along Lake Victoria, and spread to Kenya's third largest city (Kisumu) in mid-October, to join the Siaya District, northwest, by early November.
In 2009, Kenya reported 11,769 cases including 274 deaths, the largest number of cases in the last ten years. By January 2010, outbreaks had affected 31 districts nationwide, causing a total of 3,024 cases and 53 deaths.
In Kenya outbreaks are related to poor access to drinking water and effective sanitation systems, whose factors are directly linked to high poverty levels, ignorance of prevention measures, low latrine coverage and inappropriate traditional beliefs (Disaster Relief Emergency Fund (DREF), Operation report n°03, 2009). Refugee camps located in North Eastern Province of Kenya were also a source of cholera outbreaks.
Routine cholera surveillance is conducted as part of the Integrated Disease Surveillance and Response system and is overseen by the Department of Disease Prevention and Control in the Ministry of Public Health and Sanitation. The Disease Outbreak Management Unit is responsible for monitoring cholera activity and responding to outbreaks. The Kenya's International Emerging Infections Program is based at the Kenyan Medical Research Institute in Nairobi and Kisumu, and national, provincial and district health offices actively participate in program operations.
A national system for routine disease surveillance is established in Kenya, and includes regular reporting. Cases are detected through daily and weekly reporting. When a case occurs, it is reported to the health facility or laboratory to the District Surveillance Officer, and then, to the regional and national level. The National Public Health Laboratory (NPHL) and/or KEMRI are involved with confirmation of specimens. This data is entered into a database and a weekly epidemiological bulletin is produced and disseminated to persons on the e-mail distribution list.
Africhol collaborated with the Kenya Ministry of Public Health and Sanitation to strengthen the cholera routine surveillance system.
Since 1973, cholera has been endemic in Mozambique. During the 1990s notified cholera cases from Mozambique represented one third of all African cases, with up to 31,731 cases reported in 1992.
Since October 2007, Mozambique has reported cases almost every week to the WHO. The last cholera outbreak started in 2009, causing 19,310 cases and 155 deaths. Cases drastically decreased between November and December 2009, but heavy rains in the first quarter of 2010 resulted in a renewed outbreak.
The first cholera cases in Tanzania were reported in 1974. From 1977 to 1992, cases were reported each year with a case fatality rate ranging between 1.8% and 11.4%. The first major cholera outbreak occurred in 1992 when 18,526 cases and 2,173 deaths were recorded (CFR 11.7%).
In 1997, an epidemic that started at the end of January in Dar es Salaam accounted for 40,249 cases and 2,231 deaths (CFR 5.54%). Between 2002 and 2006, most Tanzanian regions have reported cholera cases and nine of them reported more than 2,000 cases. During 2006, a total of 14,297 cases were reported from 16 regions, including 254 deaths. Dar es Salaam was the most affected region, accounting for 63% of the total cases and 40% of the total deaths.
Cholera surveillance is conducted by the section for Epidemiology and Disease Control within the Ministry of Health and Social Welfare. Under the current Integrated Disease Surveillance and Response strategy, health facilities in Tanzania are required to immediately notify the district when they suspect an outbreak, and to provide weekly reports for seven outbreak-prone diseases, and monthly reports for 13 priority diseases.
For suspect cholera cases, all health centers must investigate all cases of severe diarrhea. Suspected cases or deaths from cholera must be reported to the nearest health center and from there to the District Medical Officer (DMO), who must confirm the outbreak based on the laboratory results. The DMO is supposed to report to the District Commissioner, District Executive Director and Regional Medical officer in less than 12 hours.
In Togo, cholera occurs in an endemo-epidemic pattern, with the capital, Lomé city, accounting for more than two-thirds of total cases during the past five years; the remaining cases were spread over the Maritime and Plateaux regions.
The first epidemic was reported in 1971 and accounted for 335 cases. Between 1970 and 2009, a total number of 15,870 cholera cases has been reported to the WHO. Since 2005, 3,234 cases of cholera were reported by the Togolese Ministry of Health, with 48 related deaths.
The last cholera outbreak occurred in Lomé in 2010 and lasted from October to November, corresponding to a period of major flooding in the region. The monthly attack rate during October was 3.6 cases per 100,000. Previously, the city monthly incidence rate had reached 25 cases per 100,000 during January 2006.
The case fatality rate oscillates between years, from 0.5% in 2009 to 4.0% in 2010. In Lomé, cholera rarely causes death, due to appropriate and free medical care.
Uganda reported its first cholera epidemic in 1979, and suffered the biggest epidemic ever recorded in 1998. This major outbreak started at the end of 1997 and by the end of June 1998, a total of 38,697 cases and 1,576 deaths had been officially reported.
Since 1995, the annual total number of reported cases ranged from 241 in 2001 to 5,194 in 2006, During March-April 2003, the Ugandan Ministry of Public Health reported a total of 277 cases with 35 deaths in Bundibugyo district, with most cases located along the Semliki and Lamia rivers. In 2010, cholera outbreaks were reported in eight districts in the Central and the Eastern Regions, and in the Karamoja sub-Region, with a total of 1,732 cases and 53 deaths.
In Uganda, sporadic cholera cases are reported throughout the year, especially during the rainy season, when waste is often carried into rivers and lakes where people continue to collect drinking water. The major outbreak in Kampala in 1997-1998 was associated with changing weather patterns due to the occurrence of El Nino that year. The cholera situation in the country is also exacerbated by overcrowded refugee camps [International Federation of Red Cross and Red Crescent Societies, Uganda: Epidemic Cholera 2009].
Annual national summaries from WHO record case fatality rates ranging from 1.1% in 2007 to 13.7% in 1996.