Results from the second WHO external quality assessment for the molecular detection of respiratory syncytial virus, 2019-2020.

Background: External quality assessments (EQAs) for the molecular detection of human respiratory syncytial virus (RSV) are necessary to ensure the standardisation of reliable results. The Phase II, 2019-2020 World Health Organization (WHO) RSV EQA included 28 laboratories in 26 countries. The EQA panel evaluated performance in the molecular detection and subtyping of RSV-A and RSV-B. This manuscript describes the preparation, distribution, and analysis of the 2019-2020 WHO RSV EQA. Methods: Panel isolates underwent whole genome sequencing and in silico primer matching. The final panel included nine contemporary, one historical virus and two negative controls. The EQA panel was manufactured and distributed by the UK National External Quality Assessment Service (UK NEQAS). National laboratories used WHO reference assays developed by the United States Centers for Disease Control and Prevention, an RSV subtyping assay developed by the Victorian Infectious Diseases Reference Laboratory (Australia), or other in-house or commercial assays already in use at their laboratories. Results: An in silico analysis of isolates showed a good match to assay primer/probes. The panel was distributed to 28 laboratories. Isolates were correctly identified in 98% of samples for detection and 99.6% for subtyping. Conclusions: The WHO RSV EQA 2019-2020 showed that laboratories performed at high standards. Updating the composition of RSV molecular EQAs with contemporary strains to ensure representation of circulating strains, and ensuring primer matching with EQA panel viruses, is advantageous in assessing diagnostic competencies of laboratories. Ongoing EQAs are recommended because of continued evolution of mismatches between current circulating strains and existing primer sets.

Dengue virus serotype 2 imported case from Côte d'Ivoire to Senegal, 2017.

Dengue fever is the most common arboviral infection worldwide. Its epidemiology in Africa is not yet fully understood due to the lack of awareness, the presence of other dengue-like febrile diseases, and insufficient laboratory capabilities. This paper reports on the import of dengue virus serotype 2 case from Côte d'Ivoire to Senegal in West Africa. Phylogenetic analysis based on full-length genome sequence revealed that the isolate clustered with strains of cosmopolitan genotypes from the Burkina Faso outbreak in 2016 and those from the ongoing dengue fever outbreak in Côte d'Ivoire. This suggests a possible spread of strains from the Burkina Faso outbreak to other West African countries including Côte d'Ivoire and Senegal.

Human respiratory syncytial virus and influenza seasonality patterns-Early findings from the WHO global respiratory syncytial virus surveillance.

BACKGROUND: Human respiratory syncytial virus (RSV) causes illnesses among all age groups and presents a burden to healthcare services. To better understand the epidemiology and seasonality of RSV in different geographical areas, the World Health Organization (WHO) coordinated a pilot initiative to access the feasibility of establishing RSV surveillance using the existing Global Influenza Surveillance and Response System (GISRS) platform. OBJECTIVES: To describe and compare RSV and influenza seasonality in countries in the northern andsouthern temperate, and tropics during the period January 2017 to April 2019. METHODS: Fourteen countries in six WHO regions participating in the GISRS were invited for the pilot. Hospitalized patients presenting with severe acute respiratory illness (SARI), SARI without fever and outpatients presenting with acute respiratory illness (ARI) were enrolled from January 2017 to April 2019. The expected minimum sample size was 20 samples per week, year-round, per country. Real-time RT-PCR was used to detect RSV and influenza viruses. Results were uploaded to the WHO FluMart platform. RESULTS: Annual seasonality of RSV was observed in all countries, which overlapped to a large extent with the influenza activity. In countries, in temperate regions RSV peaked in the autumn/winter months. In Egypt, a subtropical country, RSV activity peaked in the cooler season. In the tropical regions, RSV peaked during the rainy seasons. CONCLUSION: Early findings from the WHO RSV surveillance pilot based on the GISRS suggest annual seasonal patterns for of RSV circulation that overlap with influenza. RSV surveillance needs to be continued for several more seasons to establish seasonality patterns to inform prevention and control strategies.

The epidemiological signature of influenza B virus and its B/Victoria and B/Yamagata lineages in the 21st century.

We describe the epidemiological characteristics, pattern of circulation, and geographical distribution of influenza B viruses and its lineages using data from the Global Influenza B Study. We included over 1.8 million influenza cases occurred in thirty-one countries during 2000-2018. We calculated the proportion of cases caused by influenza B and its lineages; determined the timing of influenza A and B epidemics; compared the age distribution of B/Victoria and B/Yamagata cases; and evaluated the frequency of lineage-level mismatch for the trivalent vaccine. The median proportion of influenza cases caused by influenza B virus was 23.4%, with a tendency (borderline statistical significance, p = 0.060) to be higher in tropical vs. temperate countries. Influenza B was the dominant virus type in about one every seven seasons. In temperate countries, influenza B epidemics occurred on average three weeks later than influenza A epidemics; no consistent pattern emerged in the tropics. The two B lineages caused a comparable proportion of influenza B cases globally, however the B/Yamagata was more frequent in temperate countries, and the B/Victoria in the tropics (p = 0.048). B/Yamagata patients were significantly older than B/Victoria patients in almost all countries. A lineage-level vaccine mismatch was observed in over 40% of seasons in temperate countries and in 30% of seasons in the tropics. The type B virus caused a substantial proportion of influenza infections globally in the 21st century, and its two virus lineages differed in terms of age and geographical distribution of patients. These findings will help inform health policy decisions aiming to reduce disease burden associated with seasonal influenza.

Fatal Case of Lassa Fever, Bangolo District, Côte d'Ivoire, 2015.

Lassa fever has not been reported in Côte d'Ivoire. We performed a retrospective analysis of human serum samples collected in Côte d'Ivoire in the dry seasons (January-April) during 2015-2018. We identified a fatal human case of Lassa fever in the Bangolo District of western Côte d'Ivoire during 2015.

DETECTION OF NON-INFLUENZA VIRUSES IN ACUTE RESPIRATORY INFECTIONS IN CHILDREN UNDER FIVE-YEAR-OLD IN COTE D'IVOIRE (JANUARY - DECEMBER 2013).

BACKGROUND: Influenza sentinel surveillance in Cote d'Ivoire showed that 70% of Acute Respiratory Infections (ARI) cases remained without etiology. This work aims to describe the epidemiological, clinical, and virological pattern of ARI that tested negative for influenza virus, in children under five years old. MATERIALS AND METHODS: one thousand and fifty nine samples of patients presenting influenza Like Illness (ILI) or Severe Acute Respiratory Infections (SARI) symptoms were tested for other respiratory viruses using multiplex RT-PCR assays targeting 10 respiratory viruses. RESULTS: The following pathogens were detected as follows, hRV 31,92% (98/307), hRSV 24.4% (75/329), PIV 20.5% (63/307), HCoV 229E 12,05% (37/307), hMPV 6.2% (19/307), HCoVOC43 1.0% (3/307) and EnV 1.0% (3/307). Among the 1,059 specimens analyzed, 917 (86.6%) were ILI samples and 142 (23.4%) were SARI samples. The proportion of children infected with at least one virus was 29.8% (273/917) in ILI cases and 23.9% (34/142) in SARI cases. The most prevalent viruses, responsible for ILI cases were hRV with 35.89% (98/273) and hRSV in SARI cases with 41.2% (14/34) of cases. Among the 1,059 patients, only 22 (2.1%) children presented risk factors related to the severity of influenza virus infection. CONCLUSION: This study showed that respiratory viruses play an important role in the etiology of ARI in children. For a better understanding of the epidemiology of ARI and improved case management, it would be interesting in this context to expand the surveillance of influenza to other respiratory viruses.

Epidemiology of rubella infection and genotyping of rubella virus in Cote d'Ivoire, 2012-2016.

Rubella is a contagious disease caused by the rubella virus (RuV) that can lead to serious birth defects when women are infected in early pregnancy. This study aimed to describe the epidemiology and genetic diversity of rubella viruses in Cote d'Ivoire (CIV). Blood or oral fluid samples collected from suspected measles cases were first tested for the presence of measles specific IgM antibodies by enzyme-linked immunosorbent assay (ELISA). All measles IgM negative or indeterminate samples were tested for rubella IgM antibody using ELISA. Rubella-IgM-positive samples were tested by real-time reverse transcription polymerase chain reaction (RT-PCR) for the presence of rubella virus RNA. Real-time RT-PCR-positive RNA samples were used as template to amplify the 739 nt region used for rubella genotyping. PCR-positive samples were sequenced and phylogenetic analysis performed. Between 2012 and 2016, 4121 serums and 126 oral fluids were collected through the measles surveillance system. Of these, 3823 and 108 respectively were measles IgM negative or indeterminate. Subsequent testing for rubella found that 690 of 3823 (18%) serum samples and 25 of 108 (23%) oral fluid samples were rubella IgM-positive. The 739 nt segment of the E1 glycoprotein gene was amplified and sequenced for two serums and seven oral fluids samples. Phylogenetic analysis showed that the rubella viruses from CIV belonged to genotypes 1G (eight samples) and 2B (one sample). Rubella virus genotype 2B was found in CIV for the first time. These data contribute to baseline information on rubella virus strains found in CIV before the introduction of rubella vaccine.

Distribution of influenza virus types by age using case-based global surveillance data from twenty-nine countries, 1999-2014.

BACKGROUND: Influenza disease burden varies by age and this has important public health implications. We compared the proportional distribution of different influenza virus types within age strata using surveillance data from twenty-nine countries during 1999-2014 (N=358,796 influenza cases). METHODS: For each virus, we calculated a Relative Illness Ratio (defined as the ratio of the percentage of cases in an age group to the percentage of the country population in the same age group) for young children (0-4 years), older children (5-17 years), young adults (18-39 years), older adults (40-64 years), and the elderly (65+ years). We used random-effects meta-analysis models to obtain summary relative illness ratios (sRIRs), and conducted meta-regression and sub-group analyses to explore causes of between-estimates heterogeneity. RESULTS: The influenza virus with highest sRIR was A(H1N1) for young children, B for older children, A(H1N1)pdm2009 for adults, and (A(H3N2) for the elderly. As expected, considering the diverse nature of the national surveillance datasets included in our analysis, between-estimates heterogeneity was high (I2>90%) for most sRIRs. The variations of countries' geographic, demographic and economic characteristics and the proportion of outpatients among reported influenza cases explained only part of the heterogeneity, suggesting that multiple factors were at play. CONCLUSIONS: These results highlight the importance of presenting burden of disease estimates by age group and virus (sub)type.

Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?

INTRODUCTION: Determining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes. METHODS: This was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with ≥80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics. RESULTS: 212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics. DISCUSSION: Our findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate.

Epidemiological and virological characteristics of influenza B: results of the Global Influenza B Study.

INTRODUCTION: Literature on influenza focuses on influenza A, despite influenza B having a large public health impact. The Global Influenza B Study aims to collect information on global epidemiology and burden of disease of influenza B since 2000. METHODS: Twenty-six countries in the Southern (n = 5) and Northern (n = 7) hemispheres and intertropical belt (n = 14) provided virological and epidemiological data. We calculated the proportion of influenza cases due to type B and Victoria and Yamagata lineages in each country and season; tested the correlation between proportion of influenza B and maximum weekly influenza-like illness (ILI) rate during the same season; determined the frequency of vaccine mismatches; and described the age distribution of cases by virus type. RESULTS: The database included 935 673 influenza cases (2000-2013). Overall median proportion of influenza B was 22·6%, with no statistically significant differences across seasons. During seasons where influenza B was dominant or co-circulated (>20% of total detections), Victoria and Yamagata lineages predominated during 64% and 36% of seasons, respectively, and a vaccine mismatch was observed in ≈25% of seasons. Proportion of influenza B was inversely correlated with maximum ILI rate in the same season in the Northern and (with borderline significance) Southern hemispheres. Patients infected with influenza B were usually younger (5-17 years) than patients infected with influenza A. CONCLUSION: Influenza B is a common disease with some epidemiological differences from influenza A. This should be considered when optimizing control/prevention strategies in different regions and reducing the global burden of disease due to influenza.

Multiyear persistence of 2 pandemic A/H1N1 influenza virus lineages in West Africa.

Our understanding of the global ecology of influenza viruses is impeded by historically low levels of viral surveillance in Africa. Increased genetic sequencing of African A/H1N1 pandemic influenza viruses during 2009-2013 revealed multiyear persistence of 2 viral lineages within West Africa, raising questions about the roles of reduced air traffic and the asynchrony of seasonal influenza epidemics among West African countries in the evolution of independent lineages. The potential for novel influenza virus lineages to evolve within Africa warrants intensified influenza surveillance in Africa and other understudied areas.

Investigation of an outbreak of acute respiratory disease in côte d'ivoire in april 2007.

BACKGROUND: This study aim was to investigate an outbreak of human cases of unexplained influenza-like illness and fatal acute respiratory infection (ARI), with simultaneous poultry illness and high mortality raising concerns of possible influenza A (H5N1), virus in Cote d'Ivoire in February and March 2007. MATERIALS AND METHODS: To investigate the outbreak, we conducted active surveillance in the community and reviewed health registries. Persons meeting the case definition were asked to provide nasopharyngeal specimens. On the basis of clinical and epidemiological information, specimens were tested using conventional RT-PCR for the M gene of the influenza viruses and hemagglutinin H5 of avian influenza A (H5N1), virus; negative samples were tested for other respiratory viruses. Specimens from healthy animals were also collected. RESULTS: Between October 2006, and February 2007, 104 suspected cases of Acute Respiratory Disease that included; 31 deaths recorded. We collected and tested 73 nasopharyngeal specimens; of which, 2, were positive for human Coronavirus OC43 and 1 for influenza C virus. No pathogens were identified in animal specimens. CONCLUSIONS: The investigation quickly ruled out influenza A (H5N1), virus as the cause and found laboratory-confirmed cases of influenza C virus and human Coronavirus OC 43 for the first time in both Côte d'Ivoire and in a Sub-Saharan African country. However we were not able to show that these viruses caused the outbreak. Monitoring of influenza viruses must be a priority but other respiratory viruses and non-viral causes may be of interest too.

Comparing influenza positivity rates by real-time rt-pcr, elisa and viral culture methods in Cote d'Ivoire, West Africa, in 2009

Detection of circulating influenza strains is a key public health concern especially in limited-resource settings where diagnosis capabilities remain a challenge. As part of multi-site surveillance in Cote d'Ivoire during the 2009 influenza A(H1N1) pandemic; we had the opportunity to test respiratory specimens collected from patients with acute respiratory illness (ARI). We analyzed and compared the percentage of specimens testing positive using three laboratory methods (rtRT-PCR; ELISA; viral culture). From January to October 2009; 1;356 respiratory specimens were collected from patients with acute respiratory illness and shipped at the WHO NIC (Institut Pasteur) Cote d'Ivoire; and 453 (33) tested positive for influenza by one or more laboratory methods. The proportion of positive influenza tests did not differ by the sex or age of the patient or presenting symptoms; but did differ depending on the timing and site of specimen collection. Of the 453 positive specimens; 424 (93.6) were detected by PCR; 199 (43.9) by ELISA and 40 (8.8) by viral culture. While seasonal influenza A(H1N1) virus strains were prominent; only four 2009 pandemic influenza A(H1N1) cases were detected. Use of molecular biology method (rtRT-PCR) increased sensitivity and diagnosis capabilities. Among all three methods used; rRT-PCR was the most sensitive and rapid method. More capacity building is still required for viral culture. Need to collect denominator data in order to have an accurate estimate of the burden of influenza. There was delayed introduction of pandemic influenza A(H1N1)2009 in Cote d'Ivoire

Investigation of an outbreak of acute respiratory disease in Côte d'Ivoire in april 2007

Background: This study aim was to investigate an outbreak of human cases of unexplained influenza-like illness and fatal acute respiratory infection (ARI); with simultaneous poultry illness and high mortality raising concerns of possible influenza A (H5N1); virus in Cote d'Ivoire in February and March 2007. Materials and Methods: To investigate the outbreak; we conducted active surveillance in the community and reviewed health registries. Persons meeting the case definition were asked to provide nasopharyngeal specimens. On the basis of clinical and epidemiological information; specimens were tested using conventional RT-PCR for the M gene of the influenza viruses and hemagglutinin H5 of avian influenza A (H5N1); virus; negative samples were tested for other respiratory viruses. Specimens from healthy animals were also collected. Results: Between October 2006; and February 2007; 104 suspected cases of Acute Respiratory Disease that included; 31 deaths recorded. We collected and tested 73 nasopharyngeal specimens; of which; 2; were positive for human Coronavirus OC43 and 1 for influenza C virus. No pathogens were identified in animal specimens. Conclusions: The investigation quickly ruled out influenza A (H5N1); virus as the cause and found laboratory-confirmed cases of influenza C virus and human Coronavirus OC 43 for the first time in both Cote d'Ivoire and in a Sub-Saharan African country. However we were not able to show that these viruses caused the outbreak. Monitoring of influenza viruses must be a priority but other respiratory viruses and non-viral causes may be of interest too

Pandemic Influenza A(H1N1) in Cote d'Ivoire: health-care providers' knowledge of influenza and attitudes towards vaccination.

INTRODUCTION: During the 2009 influenza A(H1N1) pandemic (pH1N1), different methods were promoted to reduce the spread of influenza, including respiratory etiquette and vaccination. To identify knowledge gaps about influenza and to plan the vaccination campaign against the pandemic in Côte d'Ivoire, a survey was conducted among health-care providers (HCPs) to assess their knowledge about influenza and their willingness to be vaccinated. METHODOLOGY: A cross-sectional survey was performed in the city of Abidjan on 16-18 February 2010, in the three university teaching hospitals, a randomly selected general hospital, and two randomly selected private clinics. In face-to-face interviews, 383 health-care professionals were asked questions about their knowledge of influenza, means of influenza prevention, and their willingness to be vaccinated. Data analysis, both univariate and multivariate, was performed using SPSS. RESULTS: Willingness to be vaccinated against pH1N1 was 80% (n = 284), and 83% of the HCPs would recommend the vaccine to others. The respiratory mode of transmission of influenza was known by 85% (n = 295) of the participants and 50% (n = 174) believed that seasonal influenza virus and pH1N1 virus were different. In a multivariate model, the factors significantly associated with willingness to receive pH1N1vaccine were fear of pH1N1 disease (OR = 2.1; IC = 1.02-4.35), having only a high school education (OR = 8.28; IC = 2.04-33.60), and feeling at risk to contract pH1N1 (OR = 11.43; IC = 4.77-27.38). CONCLUSION: The willingness to be vaccinated against influenza A (H1N1) by health professionals is real.

Comparing Influenza Positivity Rates by Real-Time RT-PCR, Elisa and Viral Culture Methods in Côte D'Ivoire, West Africa, in 2009.

Detection of circulating influenza strains is a key public health concern especially in limited-resource settings where diagnosis capabilities remain a challenge. As part of multi-site surveillance in Côte d'Ivoire during the 2009 influenza A(H1N1) pandemic, we had the opportunity to test respiratory specimens collected from patients with acute respiratory illness (ARI). We analyzed and compared the percentage of specimens testing positive using three laboratory methods (rtRT-PCR, ELISA, viral culture). From January to October 2009, 1,356 respiratory specimens were collected from patients with acute respiratory illness and shipped at the WHO NIC (Institut Pasteur) Cote d'Ivoire, and 453 (33%) tested positive for influenza by one or more laboratory methods. The proportion of positive influenza tests did not differ by the sex or age of the patient or presenting symptoms, but did differ depending on the timing and site of specimen collection. Of the 453 positive specimens, 424 (93.6%) were detected by PCR, 199 (43.9%) by ELISA and 40 (8.8%) by viral culture. While seasonal influenza A(H1N1) virus strains were prominent, only four 2009 pandemic influenza A(H1N1) cases were detected. Use of molecular biology method (rtRT-PCR) increased sensitivity and diagnosis capabilities. Among all three methods used, rRT-PCR was the most sensitive and rapid method. More capacity building is still required for viral culture. Need to collect denominator data in order to have an accurate estimate of the burden of influenza. There was delayed introduction of pandemic influenza A(H1N1)2009 in Cote d'Ivoire.

Sentinel surveillance for influenza and other respiratory viruses in Côte d'Ivoire, 2003-2010.

BACKGROUND: Many countries in Africa have lacked sentinel surveillance systems for influenza and are under-represented in data used for global vaccine strain selection. OBJECTIVES: We describe 8 years of sentinel surveillance data and the contribution of influenza and other viruses to medically attended influenza-like illness (ILI) in Côte d'Ivoire. METHODS: Sentinel surveillance was established in 2003. Nasopharyngeal (NP) specimens and epidemiologic data are collected from persons of all ages presenting with ILI at sentinel sites. Respiratory specimens have been tested for influenza using various viral and molecular diagnostic methods. A subset of 470 specimens collected from children aged 0-5 years were tested for multiple respiratory viruses using RT-PCR. RESULTS: From 2003 to 2010, 5074 NP specimens were collected from patients with ILI. Overall, 969/5074 (19%) of these specimens tested positive for influenza. Seasonal influenza A(H1N1) viruses predominated during 5 years and influenza A(H3N2) viruses predominated during 3 years. Influenza B viruses cocirculated with influenza A viruses during each year from 2004 to 2010. Seasonal peaks in influenza circulation were observed during the months of May, June, and October, with the largest peak corresponding with the primary rainfall season. Of 470 specimens collected from children under aged 5 who were tested for multiple respiratory viruses, a viral respiratory pathogen was detected in 401/470 (85%) of specimens. Commonly detected viruses were RSV (113 of 470 specimens, 24%), rhinoviruses (85/470, 18%), influenza (77/470, 16%), and parainfluenza (75/470, 16%). CONCLUSION: In Côte d'Ivoire, there is a significant annual contribution of influenza and other respiratory viruses to medically attended ILI.

Vulnerable groups within a vulnerable population: awareness of the A(H1N1)pdm09 pandemic and willingness to be vaccinated among pregnant women in Ivory Coast.

BACKGROUND: Because little is known about attitudes toward influenza and influenza vaccine among pregnant women in West Africa, before local distribution of A(H1N1)pdm09 vaccine in Ivory Coast we assessed knowledge of the pandemic and acceptance of the A(H1N1)pdm09 vaccine in a diverse population of pregnant women. METHODS: A cross-sectional intercept survey of 411 pregnant women in 4 prenatal care settings was conducted during 15-28 February 2010 in Abidjan, Ivory Coast. RESULTS: The majority (64.5%) of pregnant women said they had heard of the influenza pandemic, and of these, the majority (61.3%) were aware of the A(H1N1)pdm09 vaccine. However, awareness varied significantly by clinical setting, education level, and access to media (P < .001 for all comparisons). After adjustment for other sociodemographic factors, college-educated women were 16.8 (95% confidence interval [CI], 3.3-85.2) times as likely as women without formal education to be aware of the pandemic. After controlling for both education and demographic characteristics, women with televisions were 5 times as likely as women without television to be aware of the pandemic (adjusted odds ratio [aOR], 4.94; 95% CI, 1.34-18.17). Of those aware of the influenza pandemic, 69.8% said they would accept the A(H1N1)pdm09 vaccine while they were pregnant. Although awareness was highest in private prenatal care clinics, compared with public outpatient clinics (90.6% vs 37.5%), acceptance of vaccine was significantly lower in private settings, compared with public outpatient settings (57.3% vs 87.2%; P < .001 for each comparison). CONCLUSIONS: Gaps in knowledge about the influenza pandemic and vaccine highlight the challenges of pandemic preparedness in poorer countries, where substantial disparities in education and media access are evident.

Influenza surveillance in 15 countries in Africa, 2006-2010.

BACKGROUND: In response to the potential threat of an influenza pandemic, several international institutions and governments, in partnership with African countries, invested in the development of epidemiologic and laboratory influenza surveillance capacity in Africa and the African Network of Influenza Surveillance and Epidemiology (ANISE) was formed. METHODS: We used a standardized form to collect information on influenza surveillance system characteristics, the number and percent of influenza-positive patients with influenza-like illness (ILI), or severe acute respiratory infection (SARI) and virologic data from countries participating in ANISE. RESULTS: Between 2006 and 2010, the number of ILI and SARI sites in 15 African countries increased from 21 to 127 and from 2 to 98, respectively. Children 0-4 years accounted for 48% of all ILI and SARI cases of which 22% and 10%, respectively, were positive for influenza. Influenza peaks were generally discernible in North and South Africa. Substantial cocirculation of influenza A and B occurred most years. CONCLUSIONS: Influenza is a major cause of respiratory illness in Africa, especially in children. Further strengthening influenza surveillance, along with conducting special studies on influenza burden, cost of illness, and role of other respiratory pathogens will help detect novel influenza viruses and inform and develop targeted influenza prevention policy decisions in the region.

Spatiotemporal circulation of influenza viruses in 5 African countries during 2008-2009: a collaborative study of the Institut Pasteur International Network.

BACKGROUND: Although recent work has described the spatiotemporal diffusion of influenza viruses worldwide, comprehensive data on spatiotemporal patterns of influenza from the African continent and Madagascar are still lacking. METHODS: National Influenza Centers from 5 countries-Cameroon, Côte d'Ivoire, Madagascar, Niger, and Senegal--collected specimens from patients presenting with influenza-like illness who visited sentinel surveillance clinics during a 2-year period (2008-2009). Isolates were genetically and antigenically characterized. RESULTS: Overall, 8312 specimens were tested. Seasonal influenza A virus subtypes H1N1 and H3N2 and influenza B viruses were detected in 329, 689, and 148 specimens, respectively. In 2009, pandemic influenza A virus subtype H1N1 was detected in Madagascar most commonly (98.5% of cases). Influenza activity was either significant year-round or occurred during a specific period of the year in the African countries we evaluated. CONCLUSIONS: Our results demonstrate that, from Madagascar to Senegal, the epidemiologic and virologic characteristics of influenza viruses are diverse in terms of spatiotemporal circulation of the different virus types, subtypes, and strains. Our data highlight the importance of country-specific surveillance and of data and virus sharing, and they provide a rational basis to aid policy makers to develop strategies, such as vaccination at the right moment and with the right formulation, aimed at reducing the disease burden in Africa and Madagascar.