Maladies épidémiques et pandémiques
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Factors that increase the vulnerability of many African communities to epidemics include weak health systems, high level of women’s illiteracy, poverty, inadequate water and sanitation systems, and poor general hygiene levels. These are compounded by limited public awareness, together with natural and man-made disasters.
The WHO African Region is regularly affected by epidemics sweeping through its countries, leaving already fragile health systems struggling to cope. In 1998, the Integrated Disease Surveillance and Response (IDSR) framework was adopted, with the aim of integrating and streamlining common surveillance activities and their human and financial resource costs.
These epidemics include cholera, meningitis, measles, viral haemorrhagic fever, influenza and dysentery. Meningococcal meningitis and cholera occur seasonally in many African countries, resulting in high morbidity and mortality rates.
Effective disease surveillance requires an effective early warning and response system so that control measures can be taken promptly. Since 2008, the WHO "event management system" has been in use by all countries of the Region and all countries have reported cases through the system.
For maximum benefit and efficiency, countries are encouraged to prepare consolidated, multisectoral IDSR plans, rather than exclusively disease-specific epidemic plans. The list of priority diseases in the IDSR framework has been revised to incorporate emerging diseases of public health importance, and laboratory capacity, containment and function have been analysed in respect of present abilities to support integrated IDSR and International Health Regulations (IHR) functions.
It has been decided that due to the overlap in requirements and capacities between IDSR and the revised IHR, the two entities should be considered together within the Region.
To strengthen capacity to address epidemics or pandemics, a more decentralized, district focus is necessary and the development of further tools and guidelines is required to speed compliance with IDSR and IHR provisions.
Response to epidemic and pandemic-prone diseases is a clear priority in the WHO African Region. Following a series of devastating outbreaks from epidemic-prone diseases such as cholera, meningococcal meningitis, yellow fever and viral hemorrhagic fevers, the Forty-eighth WHO Regional Committee for Africa adopted a resolution on Integrated Disease Surveillance in order to address the burden of communicable diseases, and improve the availability and use of data in detecting and responding to public health problems affecting Member States.
The Integrated Disease Surveillance and Response (IDSR) strategy promotes rational use of resources by integrating and streamlining common surveillance activities. Surveillance activities for different diseases involve similar functions (detection, reporting, analysis and interpretation, feedback, action) and often use the same structures, processes and personnel.
Recognizing that 75% of emerging and re-emerging pandemic-prone diseases that have recently occurred, for example HIV/AIDS, or avian influenza, are of animal origin, IDSR strategy has recently been revised to take into account the “one world, one health” strategy. Its priority list therefore now includes diseases at the intersection of human, domestic animal, wildlife, and ecosystem health. This chapter addresses epidemic and pandemic prone diseases as contained in the revised IDSR priority list.
Countries in the WHO African Region experience recurring epidemics of communicable diseases that have significant impact on health and economic development. Recently, some of the epidemic-prone diseases originating from the Region, for example Marburg and Ebola, have demonstrated the ability to spread internationally, thus threatening global health security.
Factors that increase the vulnerability of many African communities to epidemics include weak health systems, high level of women’s illiteracy, poverty, inadequate water and sanitation systems and poor general hygiene levels. These are compounded by limited public awareness, together with natural and man-made disasters.
Epidemic and pandemic-prone diseases frequently affecting countries in the Region, and shown on the generic IDSR priority diseases list, include cholera, meningitis, measles, viral haemorrhagic fevers (VHF) and dysentery. In 2009 and 2010, countries were significantly affected by influenza pandemic A (H1N1) 2009, Rift Valley fever, meningitis, cholera, yellow fever and dengue. Each of the 46 Member States in the Region reported at least one disease epidemic in 2009. Thirty-three countries reported influenza pandemic (H1N1) 2009, cholera occurred in 29, meningitis in 32, while two reported typhoid epidemics. Twenty-one countries in the meningitis belt with a total population of 495 million are at high risk annually during the October to May meningitis season. During the 2009 season, 93 249 cases and 6 129 deaths (CFR = 6.6 %) were reported by these countries.
Table 1: Burden of epidemic and pandemic-prone diseases in the WHO African Region, 2009
|Cholera||218,806||6,379||29||Angola, Benin, Botswana, Burundi, Cameroon, Central African Republic, Chad, Congo, Côte d'Ivoire, DR Congo, Ethiopia, Ghana, Guinea, Guinea Bissau, Kenya, Liberia, Malawi, Mozambique, Namibia, Nigeria, Rwanda, Senegal, South Africa, Swaziland, Tanzania, Togo, Uganda, Zambia, Zimbabwe|
|Cerebro spinal meningitis||93,249||6,129||32||Angola, Benin, Burkina Faso, Burundi, Cape Verde, Cameroon, Central African Republic, Chad, Côte d'Ivoire, DR Congo, Eritrea, Ethiopia, Gabon, Ghana, Guinea, Kenya, Lesotho, Liberia, Malawi, Mali, Mauritania, Mauritius, Mozambique, Niger, Nigeria, Rwanda, Senegal, Seychelles, Sierra Leone, Tanzania, Togo, Uganda|
|Dysentery||376,293||312||24||Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Congo, DR Congo, Eritrea, Gabon, Ghana, Guinea, Kenya, Malawi, Mauritius, Mozambique, Niger, Sao Tome & Principe, Senegal, Seychelles, Sierra Leone, Togo|
|Hepatitis||1,520||15||6||Botswana, Eritrea, Ghana, Lesotho, Mauritania, Seychelles|
|Measles||83,807||722||31||Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Congo, Côte d'Ivoire, DR Congo, Equatorial Guinea, Eritrea, Gabon, Ghana, Kenya, Lesotho, Liberia, Malawi, Mali, Mauritania, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, Tanzania, Togo, Zimbabwe|
|Monkey pox||1,953||27||2||DR Congo, Liberia|
|Pandemic A(H1N1) 2009||17,119||166||33||Algeria, Angola, Botswana, Burundi, Cameroon, Cape Verde, Chad, Congo, Côte d'Ivoire, DR Congo, Ethiopia, Ghana, Kenya, Lesotho, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mozambique, Namibia, Niger, Nigeria, Rwanda, Sao Tome & Principe, Senegal, Seychelles, South Africa, Swaziland, Tanzania, Uganda, Zambia, Zimbabwe|
|Plague||392||25||7||Algeria, DR Congo, Kenya, Madagascar, Malawi, Tanzania, Zambia|
|Rabies||424||284||6||Angola, Benin, Ethiopia, Liberia, Tanzania, Togo|
|Dengue||18,936||10||3||Capo Verde, Nigeria, Senegal|
|Lassa fever||233||58||6||Cameroon, Chad, Liberia, Mali, Nigeria, Sierra Leone|
|Rift valley fever||127||3||2||Madagascar, Niger|
|Yellow fever||3,276||92||16||Cameroon, Central African Republic, Chad, Congo, Côte d'Ivoire, DR Congo, Gabon, Ghana, Guinea, Kenya, Liberia, Mali, Niger, Nigeria, Senegal, Sierra Leone|
Source of data: Weekly and Monthly IDSR data reports from Member States in the WHO African Region
Meningococcal meningitis and cholera are the major epidemic-prone diseases with seasonal occurrence in the African Region, and are often associated with high rates of morbidity and mortality. Between 2004 and 2008, the reported cases of meningitis in affected countries were 170 927, including 18 117 deaths (CFR, 11%).
During the same 5-year period, 838 840 cases of cholera were reported to WHO globally. 82% of these, or 691 290 cases, were from African countries. Of the 20 093 total deaths, 17 043, or 85%, occurred in Africa. Figure 1 highlights the countries reporting cholera in 2009 and 2010.
Figure 1: Countries that reported cholera to WHO/AFRO, June 2009–June 2010
- Year 2009
- Year 2009
Source: Data reports submitted by Member States to WHO/AFRO
Other recently emerging epidemic-prone diseases such as dengue, Ebola, Marburg and chikungunya are becoming increasingly frequent in the African Region. In 2009 and 2010, the Region has experienced more than five dengue outbreaks. During the same period, it has suffered the largest outbreak of dengue hemorrhagic fever (due to dengue type 3) with over 21 000 cases reported in Cape Verde alone, including 4 deaths.
Epidemic alert and verification
Epidemic Alert and Verification Effective containment and control of outbreaks requires an efficient early warning and response system capable of detecting epidemics at an early stage, and prompting appropriate control measures. With the coming into force of the International Health Regulations (2005), WHO has been mandated to undertake certain activities when public health security across international borders is threatened. The Organization must rapidly and consistently identify and assess public health risks of potential international concern. Depending on its risk assessment, WHO must inform Member States of these threats and, when requested, assist with investigation and control. Since 2008, the WHO Regional Office for Africa has implemented the WHO Event Management System (EMS). This system supports the process of detection, risk assessment, monitoring and response to epidemic intelligence of infectious or non-infectious origin. The use of EMS as a support tool for early warning and response to outbreaks was critical to detecting the first laboratory confirmed cases of pandemic (H1N1) 2009 in the Region. Following the declaration of phase 4 in April 2009, all 46 African countries were requested to activate their respective early warning and response systems and provide daily information on any unexplained Influenza-like illness (ILI). This includes acute lower respiratory disease, severe unexplained respiratory illness occurring in health care workers providing care to patients with respiratory disease, changes in the epidemiology of mortality associated with the occurrence of ILI, or lower respiratory tract illness. All events occurring in the African Region are now being managed through the EMS. Between May 2009 and August 2010, 180 events were reported by this means. The average number of events reported by each country is 3.91.
Epidemic readiness and intervention
Epidemic Readiness and Interventions WHO and partners are providing technical and financial support to develop, update and implement countries’ epidemic/emergency preparedness and response plans to common threats. All 46 countries of the African Region have updated their influenza pandemic preparedness plans. In 2009, 21 countries in the meningitis belt5 updated their national meningitis plans. Sixteen countries have consolidated preparedness and response plans covering more than one priority disease, while the remainder has separate disease-specific plans. To better integrate all these disease-specific plans, the WHO Regional Office for Africa is in the process of developing guidelines for consolidating national epidemic preparedness and response plans.
Standard operating procedures for meningitis and avian influenza have been revised. Technical materials on cholera have been produced in four major languages and made available to all Member States. Other WHO technical guidelines are available to countries requiring them, covering viral hemorrhagic fevers, dengue and yellow fever. To facilitate close monitoring of the priority diseases, the list of diseases in the IDSR technical guidelines has been revised to include emerging diseases such as new sub-types of influenza, dengue, chikungunya, and other events of public health importance.
To maximize coordination of response to epidemics and other public health emergencies, WHO and partners have assisted countries in establishing multisectoral and multidisciplinary epidemic and emergency response committees at national and district levels. By mid-2010, 35 of the 46 countries had established these at national level, and they were present in almost half of all districts. Terms of reference have been developed to establish task forces for cholera and viral hemorrhagic fevers throughout the African Region.
The “one world, one health” holistic concept for prevention and control of zoonotic diseases is now being promoted in the Region. The underlying principle is to strengthen linkages and collaboration between the human and animal health sectors, so that a better understanding of the human-animal interface can be obtained. Specifically, countries are encouraged to incorporate technical experts into their national and district task forces from all the key sectors – agriculture, environment, veterinary, and human health – to facilitate joint preparedness and response activities.
Response to outbreaks is being further improved through the strategic pre-positioning of stocks of medical supplies, including antivirals for influenza (Tamiflu), cholera kits, and sets of personal protective equipment. Storage facilities for vaccines and laboratory materials, including cold rooms, have been established in the WHO Regional Office for Africa. Field dispensaries and radio communication equipment are also prepositioned in strategic locations. A Regional virtual Epidemic Rapid Response Team is being developed, and a database of over 400 specialized national experts prepared and maintained at the WHO Regional Office for Africa.
The Fifty-ninth Session of the WHO Regional Committee for Africa endorsed Resolution AFR/RC59/R12 proposing the creation of an African Public Health Emergency Fund, to be run as a regional intergovernmental initiative dedicated to resource mobilization for emergency preparedness. A framework for the operation of this fund has been developed, and considered at the Regional Committee’s Sixtieth Session.
To support all these measures, the WHO Regional Office for Africa has now established a Strategic Health Operations Centre (SHOC). This greatly facilitates communication at times of emergency within and beyond the Region, including with WHO/HQ and other WHO regional operations centres.
Laboratory and containment
A strong national laboratory network composed of public health, animal health and other sectors is essential for the successful implementation of IDSR and the International Health Regulations (IHR) as revised in 2005. The organization of laboratory diagnostics should be based on a reliable sample collection and transport system, adequate domestic diagnostic capacity for the priority diseases or events, and the use of outside capacity when needed.
The WHO African Regional Office has therefore been working with Member States and other partners to strengthen capacity in line with the integrated disease surveillance and response strategy. Key actions that have been taken in the area of laboratories and containment include:
Strengthening Laboratory Coordination: a number of management meetings have been held to strengthen surveillance through improving laboratory diagnostic and response capacity in African countries.
Assessments of laboratory capacities: national reviews of laboratory capacities have been carried out through a standard self assessment-questionnaire and on-site visits.
Provision of guidelines and tools for laboratory methods: standard guidelines and tools for diagnosis of various priority disease and conditions have been developed to assist national public health laboratories.
External Quality Assurance Programme: all Member States are receiving assistance towards participation in the WHO External Quality Assurance (EQA) Microbiology Programme. This programme assesses laboratories’ capacity to detect epidemic-prone diseases.
Reporting, communication and information-sharing: the laboratory networks maintain active communication with Members States through weekly reports on IDSR priority diseases.
Technical workshops and containment: two sub-regional workshops on safe shipment of infectious substances (IATA) were held in September 2008 and January 2009. Disease- specific on-site training on plague diagnosis and containment has also been performed. Capacity within the Region to monitor emerging antimicrobial resistance to priority diseases has been strengthened through training courses, and laboratories are participating in the EQA programme mentioned above.
Current Challenges: while laboratories have made great progress in surveillance of and response to priority health events, some challenges remain. The following areas need strengthening: policy, standards, and advocacy for laboratory services; networking between national reference health laboratories and different disciplines and sectors; continuing education and training for laboratory personnel; promotion of quality assurance programs; timely laboratory confirmation of disease pathogens, and appropriate resource management.
State of integrated disease surveillance
In 2010, 12 years after the adoption and implementation of the IDSR strategy by countries of the African Region, a cross-sectional survey was carried out in all 46 countries.
The self-assessment questionnaire was administered to responsible national surveillance officers and the IHR National Focal Point. This survey examined IDSR strategy Implementation at both national and district level, and monitoring of International Health Regulations (IHR) Implementation. All but one of the 46 countries responded. Each of these had a dedicated national surveillance structure, and a list of identified IDSR priority diseases or conditions. Only 24 countries, however, had an operations command and control centre to coordinate and monitor outbreaks and other public health emergencies.
Surveillance for non-communicable diseases has now been incorporated into the recently revised IDSR technical guidelines. However, up to 30% of Member States had already begun reporting on non-communicable diseases, notably hypertension and diabetes mellitus, prior to the availability of the revised guidelines.
The following gaps in district level implementation of IDSR have been identified:
- Absence of IDSR dedicated data staff at district level in 30% of countries
- Lack of epidemic management committees in over 80% of districts
- Absence of rapid response teams in over 50% of districts
- Lack of logistic and communication capacity in many districts
- Lack of consistency in the use of IDSR core indicators in monitoring and evaluating performance at all levels.
Nevertheless, IDSR remains a reliable strategy for implementing district level surveillance in African countries. The survey showed that all Member States should revise their tools and guidelines to incorporate IHR and non-communicable disease surveillance, continue to build capacity to fully implement IDSR at all levels, develop a strong surveillance monitoring and evaluation system for surveillance, and mobilize resources.
Implementation of International Health Regulations (2005)
Under the International Health Regulations (2005) adopted by the Fifty-eighth World Health Assembly, all Member States made a commitment to assess their national core capacities for surveillance and response within two years of the IHR coming into force in June 2007. They equally undertook to develop and maintain these core capacities over a period of five years, with a two-year extension if needed. These core capacities overlap with those required for the IDSR, and include legislation, policy and coordination, surveillance, preparedness, response, risk communication, laboratory capacity, and human resources. By the end of 2012, all Member States should have the necessary capacity in place to implement the revised IHR.
Since the coming into force of the 2005 IHR, some progress has been made in the African Region. Countries have examined the requirements, and commenced the incorporation of IHR provisions into their national IDSR guidelines. A national public health laboratory network has been established in the majority of Member States, and these are participating in external quality assurance schemes for various priority diseases defined under IDSR. Most countries have started raising awareness on the IHR among National Focal Points, Surveillance Officers and other stakeholders. A regional IHR coordination meeting for 126 stakeholders has taken place.
Links between IDSR and IHR
The IHR provide an opportunity to address threats to international public health security and trade caused by reemerging and emerging infectious diseases, including public health emergencies of international concern (PHEIC). They also serve to strengthen surveillance and response systems, and to act as a potent driver for IDSR implementation. Because of the close linkage between the IDSR and the IHR, Member States in the African Region intend to implement the IHR (2005) in the context of IDSR. Several challenges remain, however. These include high turnover of National Focal Points, delay in revision of IDSR technical guidelines and a lack of the tools needed to successfully incorporate the IHR; delays in meeting IHR core capacities and complying with the IHR requirements; and delay in timely notification of all events constituting public health emergency of national or international concern.
Endnotes: Sources, methods, abbreviations, etc.
List of Tables/Figures
Table 1: Burden of epidemic and pandemic-prone diseases in the WHO African Region, 2009 (incorporated into text)
Figure 1: Countries that reported cholera to WHO/AFRO, June 2009–June 2010 Source: Data reports submitted by Member States to WHO/AFRO
No Atlas figures on Epidemics
1. Resolution AFR/RC48/R2, Integrated Disease Surveillance: Regional strategy for communicable diseases. In : Forty-eighth Session of the WHO Regional Committee for Africa, Harare, Zimbabwe, September 1998, Final Report. Harare, Regional Office for Africa, World Health Organization, 1998.
2. Technical Guidelines for Integrated Disease Surveillance and response in the African Region, revised version, August 2010, Regional Office for Africa, Brazzaville, WHO.
3. Cholera epidemics were reported in 2009 by Angola, Benin, Burundi, Cameroun, Congo, DRC, Ethiopia, Liberia, Kenya, Malawi, Mozambique, Namibia, Nigeria, Rwanda, South Africa, Tanzania, Swaziland, Uganda, Zambia and Zimbabwe.
4. Meningitis epidemics were reported in 2009 by Burkina Faso, Cameroun, Chad, Central African Republic, DRC, Niger and Nigeria.
5. The meningitis belt stretches from Senegal to Ethiopia. The countries in the belt are Benin, Burkina Faso, Cameroun, Central African Republic, Chad, Eritrea, Ethiopia, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Kenya, Mali, Mauritania, Niger, Nigeria, Senegal, Sudan, Togo and Uganda.
6. 14 of the 21 countries that reported meningitis cases are Benin, Burkina Faso, Cameroun, Central African Republic, Chad, Eritrea, Ethiopia, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Kenya, Mali.
7. Data source: WHO-Multi-Disease Surveillance Centre, Ouagadougou, Burkina Faso http://www.who.int/csr/disease/meningococcal/epidemiological/en/index.html last accessed 17 August 2010
8. Data source: WHO Global Health Atlas, http://apps.who.int/globalatlas last accessed 17 August 2010.
9. Countries that reported having consolidated EPR plans include Benin, Burkina Faso, Cameroon, CAR, Congo, Cote d’Ivoire, DRC, Ghana, Guinea, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone and Togo
10. Cholera technical materials were produced in English, French, Portuguese and Kiswahili.
11. The designated points are Harare, Zimbabwe, Libreville, Gabon and Ouagadougou, Burkina Faso.
12. World Health Assembly Resolution WHA 58.3, May 2005, Geneva, Switzerland.
- ↑ Resolution AFR/RC48/R2, Integrated Disease Surveillance: Regional strategy for communicable diseases. In : Forty-eighth Session of the WHO Regional Committee for Africa, Harare, Zimbabwe, September 1998, Final Report. Harare, Regional Office for Africa, World Health Organization, 1998.
- ↑ Technical Guidelines for Integrated Disease Surveillance and response in the African Region, revised version, August 2010, Regional Office for Africa, Brazzaville, WHO.
- ↑ Cholera epidemics were reported in 2009 by Angola, Benin, Burundi, Cameroun, Congo, DRC, Ethiopia, Liberia, Kenya, Malawi, Mozambique, Namibia, Nigeria, Rwanda, South Africa, Tanzania, Swaziland, Uganda, Zambia and Zimbabwe.
- ↑ Meningitis epidemics were reported in 2009 by Burkina Faso, Cameroun, Chad, Central African Republic, DRC, Niger and Nigeria.
- ↑ The meningitis belt stretches from Senegal to Ethiopia. The countries in the belt are Benin, Burkina Faso, Cameroun, Central African Republic, Chad, Eritrea, Ethiopia, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Kenya, Mali, Mauritania, Niger, Nigeria, Senegal, Sudan, Togo and Uganda.
- ↑ 14 of the 21 countries that reported meningitis cases are Benin, Burkina Faso, Cameroun, Central African Republic, Chad, Eritrea, Ethiopia, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Kenya, Mali
- ↑ Data source: WHO-Multi-Disease Surveillance Centre, Ouagadougou, Burkina Faso http://www.who.int/csr/disease/meningococcal/epidemiological/en/index.html last accessed 17 August 2010
- ↑ Data source: WHO Global Health Atlas, http://apps.who.int/globalatlas last accessed 17 August 2010.
- ↑ Countries that reported having consolidated EPR plans include Benin, Burkina Faso, Cameroon, CAR, Congo, Cote d’Ivoire, DRC, Ghana, Guinea, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone and Togo
- ↑ Cholera technical materials were produced in English, French, Portuguese and Kiswahili.
- ↑ The designated points are Harare, Zimbabwe, Libreville, Gabon and Ouagadougou, Burkina Faso.
- ↑ World Health Assembly Resolution WHA 58.3, May 2005, Geneva, Switzerland.