Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses

Introduction: In Africa, the burden of influenza is largely unknown since surveillance schemes exist in very few countries. The National Institute of Hygiene in Morocco implemented a sentinel network for influenza surveillance in 1996. Methodology: Epidemiological and virological surveillances were established and influenza viruses circulating in Morocco were characterised. Four practice-specific indicators were collected during the 1996-1997 season and nasopharyngeal swabs were collected from patients with an influenza-like illness during a three-year period (between 1996 and1998). Laboratory diagnosis was done by viral isolation. The isolates were characterized by hemagglutination- and neuraminidase-inhibition assays and by sequencing the hemagglutinin gene and phylogenetic analysis. Results: Among a total of 673 specimens, 107 (16%) were positive for influenza virus. Seasonal influenza strains were isolated from November to February. Antigenically, A(H1N1), A(H3N2) and B isolates were related to the vaccine strains. Genetically, one 1996/97 isolate A/Rabat/33/96 and the 1997/98 A(H3N2) isolates clustered with the new drift variant A/Sydney/5/97, a vaccine component of the 1998/99 season. Conclusions: These results indicate a seasonal circulation of influenza in Morocco concentrated between November and February. Further, the results demonstrate the importance of including the maximum number of countries in influenza surveillance to contribute to the definition of the influenza vaccine composition.

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Enhancing the predictive value of throat swabs in virological influenza surveillance

Eurosurveillance ◽

10.2807/esm.07.12.00389-en ◽

2002 ◽

Vol 7 (12) ◽

pp. 180-183 ◽

Cited By ~ 8

Author(s):

K Leitmeyer ◽

U Buchholz ◽

M. Kramer ◽

B Schweiger

Keyword(s):

National Survey ◽

Predictive Value ◽

Clinical Case ◽

Disease Onset ◽

Case Definition ◽

Influenza Viruses ◽

Influenza Surveillance ◽

Definition Of ◽

Virological Surveillance ◽

Clinical Case Definition

According to a national survey in Germany, the influenza virological surveillance can be improved when sentinel practitioners take throat swabs specimens only from patients who consult early after the disease onset (ie, within 48 hours), and when they use the strict clinical case definition of influenza-like illness. PCR should be used for primary detection of influenza viruses.

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What will the next influenza season bring about: seasonal influenza or the new A(H1N1)v? An analysis of German influenza surveillance data

Eurosurveillance ◽

10.2807/ese.14.32.19303-en ◽

2009 ◽

Vol 14 (32) ◽

Author(s):

H Uphoff ◽

S Geis ◽

A Grüber ◽

A M Hauri

Keyword(s):

Influenza A ◽

Seasonal Influenza ◽

Influenza Season ◽

Influenza Viruses ◽

Moderate Intensity ◽

Influenza Surveillance ◽

Influenza B ◽

Low Intensity ◽

Influenza A H1n1 ◽

Using Data

For the next influenza season (winter 2009-10) the relative contributions to virus circulation and influenza-associated morbidity of the seasonal influenza viruses A(H3N2), A(H1N1) and B, and the new influenza A(H1N1)v are still unknown. We estimated the chances of seasonal influenza to circulate during the upcoming season using data of the German influenza sentinel scheme from 1992 to 2009. We calculated type and subtype-specific indices for past exposure and the corresponding morbidity indices for each season. For the upcoming season 2009-10 our model suggests that it is unlikely that influenza A(H3N2) will circulate with more than a low intensity, seasonal A(H1N1) with more than a low to moderate intensity, and influenza B with more than a low to median intensity. The probability of a competitive circulation of seasonal influenza A with the new A(H1N1)v is low, increasing the chance for the latter to dominate the next influenza season in Germany.

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Report on influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza in 2017

Communicable Diseases Intelligence ◽

10.33321/cdi.2019.43.25 ◽

2019 ◽

Vol 43 ◽

Cited By ~ 1

Author(s):

Merryn Roe ◽

Matthew Kaye ◽

Pina Iannello ◽

Hilda Lau ◽

Iwona Buettner ◽

...

Keyword(s):

Influenza A ◽

Seasonal Influenza ◽

Vaccine Virus ◽

Influenza Viruses ◽

World Health ◽

Influenza Surveillance ◽

Influenza B ◽

Neuraminidase Inhibitors ◽

Response System ◽

Surveillance And Response

As part of its role in the World Health Organization’s (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received a record total of 5866 human influenza positive samples during 2017. Viruses were analysed for their antigenic, genetic and antiviral susceptibility properties and were propagated in qualified cells and hens’ eggs for use as potential seasonal influenza vaccine virus candidates. In 2017, influenza A(H3) viruses predominated over influenza A(H1)pdm09 and B viruses, accounting for a total of 54% of all viruses analysed. The majority of A(H1)pdm09, A(H3) and influenza B viruses analysed at the Centre were found to be antigenically similar to the respective WHO recommended vaccine strains for the Southern Hemisphere in 2017. However, phylogenetic analysis indicated that the majority of circulating A(H3) viruses had undergone genetic drift relative to the WHO recommended vaccine strain for 2017. Of 3733 samples tested for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir, only two A(H1)pdm09 viruses and one A(H3) virus showed highly reduced inhibition by oseltamivir, while just one A(H1)pdm09 virus showed highly reduced inhibition by zanamivir.

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Epidemiological and Virological Surveillance of Seasonal Influenza Viruses — China, 2020–2021

China CDC Weekly ◽

10.46234/ccdcw2021.224 ◽

2021 ◽

Vol 3 (44) ◽

pp. 918-922 ◽

Cited By ~ 1

Author(s):

Weijuan Huang ◽

◽

Xiyan Li ◽

Minju Tan ◽

Yanhui Cheng ◽

...

Keyword(s):

Seasonal Influenza ◽

Influenza Viruses ◽

Virological Surveillance

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Report on influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza in 2018

Communicable Diseases Intelligence ◽

10.33321/cdi.2020.44.16 ◽

2020 ◽

Vol 44 ◽

Author(s):

Olivia H Price ◽

Natalie Spirason ◽

Cleve Rynehart ◽

Sook Kwan Brown ◽

Angela Todd ◽

...

Keyword(s):

Influenza A ◽

Seasonal Influenza ◽

Significant Proportion ◽

Vaccine Virus ◽

Influenza Viruses ◽

World Health ◽

Influenza Surveillance ◽

Influenza B ◽

Response System ◽

Surveillance And Response

As part of its role in the World Health Organization’s (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received a total of 3993 human influenza-positive samples during 2018. Viruses were analysed for their antigenic, genetic and antiviral susceptibility properties. Selected viruses were propagated in qualified cells or hens’ eggs for use as potential seasonal influenza vaccine virus candidates. In 2018, influenza A(H1)pdm09 viruses predominated over influenza A(H3) and B viruses, accounting for a total of 53% of all viruses analysed. The majority of A(H1)pdm09, A(H3) and influenza B viruses analysed at the Centre were found to be antigenically similar to the respective WHO-recommended vaccine strains for the Southern Hemisphere in 2018. However, phylogenetic analysis indicated that a significant proportion of circulating A(H3) viruses had undergone genetic drift relative to the WHO-recommended vaccine strain for 2018. Of 2864 samples tested for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir, three A(H1)pdm09 viruses showed highly reduced inhibition by oseltamivir, while one B/Victoria virus showed highly reduced inhibition by both oseltamivir and zanamivir.

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Morbidity patterns associated with seasonal influenza A/H1N1in Swaziland

Online Journal of Public Health Informatics ◽

10.5210/ojphi.v10i1.8939 ◽

2018 ◽

Vol 10 (1) ◽

Author(s):

Vusie Lokotfwako ◽

Nhlanhla Nhlabatsi ◽

Phinda Khumalo ◽

Siphiwe Shongwe ◽

Bongani Tsabedze ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Seasonal Influenza ◽

Index Case ◽

Influenza Viruses ◽

Influenza Surveillance ◽

Influenza B ◽

Epidemic Disease ◽

Influenza A H1n1 ◽

Private Laboratory

ObjectiveTo establish morbidity patterns of influenza A/H1N1 in Swaziland from 10th July to 15th August 2017.IntroductionInfluenza infection is caused by the influenza virus, a single-stranded RNA virus belonging to the Orthomyxoviridae family. Influenza viruses are classified as types A, B and C. Influenza A and B viruses can cause epidemic disease in humans and type C viruses usually cause a mild, cold-like illness. The influenza virus spreads rapidly around the world in seasonal epidemics, resulting in significant morbidity and mortality. On the 10th of July 2017, a case of confirmed Influenza A/H1N1 was reported through the immediate disease notification system from a private hospital in the Hhohho region. A 49 year old female was diagnosed of Influenza A/H1N1 after presenting with flu-like symptoms. Contacts of the index case were followed and further positive cases were identified.MethodsUpon identification of the index case, the rapid response teams conducted further investigations. Two nasal swaps from each sample were taken and sent to a private laboratory in South Africa for the detection of the virus RNA using RT-PCR to assess for the presence Influenza A, B and Influenza A/H1N1. Further laboratory results were sourced from a private laboratory to monitor trends of influenza. Data was captured and analyzed in STATA version 12 from STATA cooperation. Descriptive statistics were carried out using means and standard deviations. The Pearson Chi square test and student t test were used to test for any possible association between influenza A/H1N1 and the explanatory variables (age and sex).ResultsSurveillance data captured between 10th July 2017 and 15th August 2017 indicated that a total of 87 patients had their samples taken for laboratory confirmation. There were 45 females and 42 males and the mean age was 27 years (SD= 17). At least 25 of the 87 patients tested positive for influenza A while only 1 tested positive for influenza B. The prevalence of influenza A/H1N1 was 16%. The prevalence of influenza A/H1N1 among males was 19% compared to 13% in females; however the difference was not statistically significant (p=0.469). There was no association noted between age and influenza A/H1N1 (p=427). Upon further sub-typing results indicated that the circulating strain was influenza A/H1N1 pdm 09 strain which is a seasonal influenza. The epidemic task forces held weekly and ad-hoc meetings to provide feedback to principals and health messaging to the general population to allay anxiety.ConclusionsThough WHO has classified the influenza A/H1N1 strain pdm 0029 as a seasonal influenza, surveillance remains important for early detection and management. There is therefore an urgent need to set up sentinel sites to monitor and understand the circulating influenza strains. Health promotion remains crucial to dispel anxiety as the general public still link any influenza to the 2009 pandemic influenza. Finally the Ministry of Health should consider introducing influenza vaccines into the routine immunization schedule especially for children.References1. Global Epidemiological Surveillance Standards for Influenza. 2014 [cited 2015 15 April]; Available from: http://www.who.int/influenza/resources/documents/influenza_surveillance_manual/en/.2. Human cases of influenza at the human-animal interface, 2013. Wkly Epidemiol Rec, 2014.89(28): p. 309-20.3. WHO Global Influenza Surveillance Network. Manual for the laboratory diagnosis and virological surveillance of influenza. 2011 [cited 2015 April27]; Available from: http://www.who.int/influenza/gisrs_laboratory/manual_diagnosis_surveillance_influenza/en/.

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Report on influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza in 2019

Communicable Diseases Intelligence ◽

10.33321/cdi.2021.45.43 ◽

2021 ◽

Vol 45 ◽

Author(s):

Heidi Peck ◽

Jean Moselen ◽

Sook Kwan Brown ◽

Megan Triantafilou ◽

Hilda Lau ◽

...

Keyword(s):

Influenza A ◽

Seasonal Influenza ◽

Significant Proportion ◽

Influenza Viruses ◽

World Health ◽

Influenza Surveillance ◽

Influenza B ◽

Surveillance And Response ◽

Influenza A H1n1 ◽

Potential Use

As part of its role in the World Health Organization’s (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received a record total of 9,266 human influenza positive samples during 2019. Viruses were analysed for their antigenic, genetic and antiviral susceptibility properties. Selected viruses were propagated in qualified cells or embryonated hen’s eggs for potential use in seasonal influenza virus vaccines. In 2019, influenza A(H3N2) viruses predominated over influenza A(H1N1)pdm09 and B viruses, accounting for a total of 51% of all viruses analysed. The majority of A(H1N1)pdm09, A(H3N2) and influenza B viruses analysed at the Centre were found to be antigenically similar to the respective WHO recommended vaccine strains for the Southern Hemisphere in 2019. However, phylogenetic analysis indicated that a significant proportion of circulating A(H3N2) viruses had undergone genetic drift relative to the WHO recommended vaccine strain for 2019. Of 5,301 samples tested for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir, four A(H1N1)pdm09 viruses showed highly reduced inhibition with oseltamivir, one A(H1N1)pdm09 virus showed highly reduced inhibition with zanamivir and three B/Victoria viruses showed highly reduced inhibition with zanamivir.

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National influenza mid-season report, 2020–2021

Canada Communicable Disease Report ◽

10.14745/ccdr.v47i01a01 ◽

2021 ◽

Vol 47 (1) ◽

pp. 1-4

Author(s):

Lisa Lee ◽

Kelly Butt ◽

Steven Buckrell ◽

Andrea Nwosu ◽

Claire Sevenhuysen ◽

...

Keyword(s):

Influenza A ◽

Seasonal Influenza ◽

Influenza Season ◽

Influenza Viruses ◽

Resistance Testing ◽

Influenza Surveillance ◽

Influenza B ◽

Strain Characterization ◽

Influenza Activity ◽

Low Levels

Canada's national influenza season typically starts in the latter half of November (week 47) and is defined as the week when at least 5% of influenza tests are positive and a minimum of 15 positive tests are observed. As of December 12, 2020 (week 50), the 2020-2021 influenza season had not begun. Only 47 laboratory-confirmed influenza detections were reported from August 23 to December 12, 2020; an unprecedentedly low number, despite higher than usual levels of influenza testing. Of this small number of detections, 64% were influenza A and 36% were influenza B. Influenza activity in Canada was at historically low levels compared with the previous five seasons. Provinces and territories reported no influenza-associated adult hospitalizations. Fewer than five hospitalizations were reported by the paediatric sentinel hospitalization network. With little influenza circulating, the National Microbiology Laboratory had not yet received samples of influenza viruses collected during the 2020-2021 season for strain characterization or antiviral resistance testing. The assessment of influenza vaccine effectiveness, typically available in mid-March, is expected to be similarly limited if low seasonal influenza circulation persists. Nevertheless, Canada's influenza surveillance system remains robust and has pivoted its syndromic, virologic and severe outcomes system components to support coronavirus disease 2019 (COVID-19) surveillance. Despite the COVID-19 pandemic, the threat of influenza epidemics and pandemics persists. It is imperative 1) to maintain surveillance of influenza, 2) to remain alert to unusual or unexpected events and 3) to be prepared to mitigate influenza epidemics when they resurge.

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Seasonal influenza during the COVID-19 pandemic in Bangladesh

PLoS ONE ◽

10.1371/journal.pone.0255646 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0255646

Author(s):

Zubair Akhtar ◽

Fahmida Chowdhury ◽

Mahmudur Rahman ◽

Probir Kumar Ghosh ◽

Md. Kaousar Ahmmed ◽

...

Keyword(s):

Seasonal Influenza ◽

Web Applications ◽

Influenza Season ◽

Tertiary Care ◽

Age Groups ◽

Influenza Viruses ◽

Control Measures ◽

Mitigation Measures ◽

Influenza Surveillance ◽

Severe Acute Respiratory Infection

Introduction During the 2019 novel coronavirus infectious disease (COVID-19) pandemic in 2020, limited data from several countries suggested reduced seasonal influenza viruses’ circulation. This was due to community mitigation measures implemented to control the pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We used sentinel surveillance data to identify changes in the 2020 influenza season compared with previous seasons in Bangladesh. Methods We used hospital-based influenza surveillance (HBIS) data of Bangladesh that are generated year-round and are population-representative severe acute respiratory infection (SARI) data for all age groups from seven public and two private tertiary care level hospitals data from 2016 to 2019. We applied the moving epidemic method (MEM) by using R language (v4.0.3), and MEM web applications (v2.14) on influenza-positive rates of SARI cases collected weekly to estimate an average seasonal influenza curve and establish epidemic thresholds. Results The 2016–2019 average season started on epi week 18 (95% CI: 15–25) and lasted 12.5 weeks (95% CI: 12–14 weeks) until week 30.5. The 2020 influenza season started on epi week 36 and ended at epi week 41, lasting for only five weeks. Therefore, influenza epidemic started 18 weeks later, was 7.5 weeks shorter, and was less intense than the average epidemic of the four previous years. The 2020 influenza season started on the same week when COVID-19 control measures were halted, and 13 weeks after the measures were relaxed. Conclusion Our findings suggest that seasonal influenza circulation in Bangladesh was delayed and less intense in 2020 than in previous years. Community mitigation measures may have contributed to this reduction of seasonal influenza transmission. These findings contribute to a limited but growing body of evidence that influenza seasons were altered globally in 2020.

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Virological surveillance of influenza viruses in the WHO European Region in 2019/20 – impact of the COVID-19 pandemic

Eurosurveillance ◽

10.2807/1560-7917.es.2020.25.46.2001822 ◽

2020 ◽

Vol 25 (46) ◽

Author(s):

Angeliki Melidou ◽

Dmitriy Pereyaslov ◽

Olav Hungnes ◽

Katarina Prosenc ◽

Erik Alm ◽

...

Keyword(s):

Northern Hemisphere ◽

Influenza A ◽

Influenza Viruses ◽

European Region ◽

Influenza Surveillance ◽

Influenza A Viruses ◽

Virological Surveillance

The COVID-19 pandemic negatively impacted the 2019/20 WHO European Region influenza surveillance. Compared with previous 4-year averages, antigenic and genetic characterisations decreased by 17% (3,140 vs 2,601) and 24% (4,474 vs 3,403). Of subtyped influenza A viruses, 56% (26,477/47,357) were A(H1)pdm09, 44% (20,880/47,357) A(H3). Of characterised B viruses, 98% (4,585/4,679) were B/Victoria. Considerable numbers of viruses antigenically differed from northern hemisphere vaccine components. In 2020/21, maintaining influenza virological surveillance, while supporting SARS-CoV-2 surveillance is crucial.

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