Communicable Diseases Epidemiological Report


In this issue
Editorial — 65
Breaking news: cerebrospinal meningitis
epidemics — 65
Summary fi ndings from IDSR weekly
surveillance of diseases in Niger during
the year 2009 — 66
Neonatal tetanus in the WHO African
Region: a call for intensifi ed action — 68
IDSR Monthly Reports fi ndings in
Botswana during the year 2009 — 70
Reported cases of pandemic AH1N1
infl uenza by country of the WHO African
Region — 72

CDER Editorial Board
Dr J. B. Roungou, Director, DPC Division
Dr F. Tshioko, CDS
Dr L. H. Ouedraogo; Dr A. A. Yahaya;
Dr P. Gaturuku; Dr F. Da Silveira;
Mr C. Corera

Contact Information
WHO/AFRO, DPC Division
Attention: CDS programme manager
BP 6, Cite du Djoué, Brazzaville, CONGO
Tel: (242) (47) 241 38000
Fax: (47) 241 38005/6
Download PDF here

CDER Editorial

Through this issue of the CDER we are happy to share with you some findings from the analysis of weekly disease surveillance data received from countries of the WHO African Region. The hottest news is that "countries of the meningitis belt are going through the epidemic season".

Together with communicable diseases, the Republic of Niger is monitoring malnutrition due to protein-energy deficiencies (PEM) on a weekly basis. This is a good example of how surveillance of noncommunicable health conditions can be jointly done with communicable disease surveillance. Analysis of the data for the year 2009 provides evidence that PEM is a major endemic condition in Niger: this fact calls for more support to this country against this underlying determinant of disease and high disease burden.

Maternal and neonatal tetanus (MNT) still occur in many countries of our Region, a situation that calls for action against this disease targeted for elimination. Since any case of neonatal tetanus is a sign of defective performance of our curative and public health services, the list of MNT-affected districts and villages should be given priority in health planning at field level. The appropriate response is through the strengthening of primary health care, including community-based surveillance and response, and the strengthening of mass immunization and routine immunization.

With regard to the timeliness and completeness of reporting, some of us still question the quality of weekly and monthly disease surveillance using aggregated data report forms in Africa. A snapshot of the level of these indicators in Tanzania is provided in this Report.

We hope you enjoy reading this issue of the CDER. Your feedback would be most welcome.

With anticipated thanks for your support,

Dr J. B. Roungou
Director, DPC Division, AFRO

Breaking news: cerebrospinal meningitis epidemics

The epidemic season has started in countries of the meningitis belt. By the week ending on 7 February 2010 the Multi-Disease Surveillance Centre of Ouagadougou (MDSC) reported that 3 districts (Pama and Titao, Burkina-Faso) and the Central African Republic (1er Arrondissement, Bangui) are in a state of epidemic. The epidemiological situation of the disease and its causal pathogens is being closely monitored by the MDSC and the affected countries for evidence based action.

Summary findings from IDSR Weekly Surveillance of Diseases in Niger during the year 2009

Analysis of Niger's weekly disease surveillance data reveals that malaria, cerebrospinal meningitis (CSM), dysentery, and measles have dominated the epidemiological situation in this country during the year 2009 (Table 1). An outbreak of CSM that claimed over 500 lives marked the first half of the year 2009, from weeks 5 to 19 (Figure 1). From week 8 to 17, more than 500 cases of the killer disease were reported per week, including more than 1,500 at the peak of the epidemic on week 17. The sharp decline usually occurs with the first rains of the year in this Sahelian country. Prompt access to treatment, proper case management and the causal pathogens (most of them being N. meningitidis rather than S. pneumoniae) explain the moderate case fatality rate, another reason being a possible high number of community deaths among defaulting patients. More details on this epidemic, including information about the causal pathogens will be shared in next issues of the CDER. .

Figure 1: Trends of cerebrospinal meningitis in Niger during the year 2009
Source: Ministry of Health Niamey, 8 January 2010 update

Some other findings are worth commenting from the findings of Niger's data analysis. A malaria epidemic followed the CSM's from weeks 33 to the end of the year (figure 2). Table 1 reminds us that Guinea worm disease (also called dracunculosis) is not eradicated in Niger yet. Measles has claimed 49 deaths. With 155 cases and 37 deaths tetanus is still not a rare disease. Protein energy malnutrition in the under five years old is highly prevalent. Laboratory information is needed about the reported cases of bloody diarrhea, diphtheria. The suspected yellow fever cases have not been lab confirmed. The good news was that there was no reported cholera case.

Table 1. Reported cases of, and deaths from, health conditions under weekly surveillance in Niger, 2009
Source: Ministry of Health Niamey, 8/1/2010 update

Malaria episodes occurred throughout the year in Niger with an epidemic pattern from week 33 to the end of the year with a peak at week 40 (Figure 2). This pattern is historically usual: therefore, public health interventions against malaria are indicated all the year long, mostly before week 33 (mid-August) in order to lower the peak.

Figure 2: Trends of Reported Malaria Episodes in Niger in 2009
Source: Ministry of Health Niamey, 8/01/2010 update

Table 2 provides a list of 30 districts that have reported tetanus cases. Priority should be given to these districts when planning anti-tetanus interventions in Niger. Because it reported a high number of cases of this disease, Birni N'Konni's district deserves a special consideration. To optimize the cost of such interventions the integrated disease surveillance (IDS) case report forms will provide the exact locations where this disease occurred.

Table 2. Reported cases of tetanus in Niger, by district, 2009
Source: Ministry of Health Niamey, 8/1/2010 update

Neonatal tetanus in the WHO African Region: a call for intensified action

Beyond the borders of Niger, neonatal and maternal tetanus remain a public health problem in the Region. Most of the countries have reported cases, with a relatively poor response rate (Table 2b)

Table 3. Performance of neonatal tetanus surveillance in the WHO African Region, Jan-Dec 2009 in the WHO African Region in 2009
Source: Ministries of Health, IDSR case-based Data

IDSR Monthly Reports findings in Botswana during the year 2009 Cases and Deaths in 2009

Cholera, cerebrospinal meningitis, influenza, dysentery and measles dominated the epidemiological situation in the Region from January to September 2009 (Table 4).

Table 4. Disease cases and deaths in Botswana as reported using the IDS monthly aggregated data
Form, Jan-Nov 2009. Source: MoH Gaborone; 12/2/2010 update
Source: Ministries of Health, IDSR case-based Data

How good can timeliness and completeness of reporting be in African countries?

Timeliness and completeness of reporting are core IDSR indicators. When they are high, they facilitate early detection of and timely response to priority health events. With regard to all reporting sites, completeness measures the representativeness of the reported facts.

From the national (MoH) level, both indicators can be measured using for numerator the number of districts that have sent reports on-time on one hand, late or on-time on the other hand. These numerators are divided by the number of districts that have the duty to report to MoH). Measured this way, timeliness and completeness of reporting have limited value. Each of the two indicators is most of the time above 80 % despite low reporting by some health facilities to their districts.

The most robust measurement of timeliness and completeness of reporting uses in its numerator and denominator the most peripheral reporting sites (clinics, dispensaries, hospitals and other health facilities) of each country's health system (Table 5). Any silent peripheral reporting site lowers the indicators away from the acceptable threshold (set at 80%). The following table shows the recent performance of Tanzania's weekly surveillance of disease system.

Table 5: Summary of epidemiological situation in the United Republic of Tanzania by the 6th week, 2009
Source: IDWE, MoH Dar Es Salaam, 24/2/2010

Table 6: Summary of key notifiable diseases in Tanzania during the year 2010 as of 24/2/2010

Nota bene: At the surveillance data aggregation level (district, province, ministry of health), failure to report cases and to detect an epidemic may in fact be due to low completeness of reporting surveillance data. Completeness of reporting comforts us in our conclusions regarding the magnitude of the health conditions being monitored and their geographical representativeness. As such it is used for the interpretation of the findings of surveillance: in any given country, poor completeness of reporting is a confounder for the observed situations. Finally silent and other poorly performing districts are lowering the national score of completeness and timeliness of reporting: given the importance of these IDSR indicators they should be supported to improve.

Table 7. Confirmed Cases of Pandemic AH1N1 Influenza by Country of the WHO African Region, 2009, Source: Member States daily Reports to WHO. 9 Feb 2009 update, DDC Afro
Source: Member States daily reports to WHO. 9 Feb. 2009 update, DPC Afro

Nota bene: "-" = zero
Senegal data are not included in this table. This country has recently reported laboratory confirmed cases. Influenza reporting has shifted to routine monitoring of Influenza-like illnesses and severe acute respiratory infections, from mostly the network of influenza surveillance laboratories including FluNet.