Announcement

Collapse
No announcement yet.

Influenza Update N° 210, 05 May 2014 (WHO, edited)

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Influenza Update N° 210, 05 May 2014 (WHO, edited)

    [Source: World Health Organization, full PDF document: (LINK). Edited.]


    Influenza Update N° 210, 05 May 2014


    Summary
    • Globally, the northern hemisphere influenza season approached interseasonal levels in most countries. Influenza B continued to comprise the majority of late season detections in most regions, with the exception of Europe which reported consistently low influenza B activity.
    • In North America, influenza levels slowly declined.
    • In Europe, influenza activity continued to decrease, and most countries either approached or reached interseasonal levels. Influenza A(H3N2) was the predominant virus, followed by A(H1N1)pdm09 and very low detections of influenza B. In eastern Europe, influenza activity declined but remained slighty elevated compared to southwest and northern Europe, which peaked earlier in the season.
    • In Eastern Asia, influenza activity approached interseasonal levels in most countries, and influenza B comprised the majority of influenza detections.
    • In Tropical Asia, influenza activity continued to decline in most countries, although some variability was seen.
    • In Northern Africa and Western Asia, influenza activity remained low in most countries, with influenza B the predominant virus detected.
    • In the Southern Hemisphere, influenza activity was still low and influenza detections were sporadic.
    For updates on human infections with avian influenza A(H7N9) virus see the WHO website http://www.who.int/influenza/human_animal_interface/influenza_h7n9/

    (...)


    Countries in the temperate zone of the northern hemisphere

    North America

    In North America, overall activity continued to slowly decline. Influenza B comprised the majority of detections, which is a shift from earlier in the season when A(H1N1)pdm09 was detected most frequently.

    However, overall activity declined and influenza A(H1N1)pdm09 remained the most commonly detected virus for the 2013-2014 season.

    Activity remained low and is past the peak of the season, however, the late season increase in influenza B circulation slowed the progression of the decline and slightly prolonged the season in some areas.

    In Canada, influenza activity remained within expected levels for this time of year, although the percent of specimens testing positive for influenza B continued to increase.

    Detections of A(H1N1)pdm09 and A(H3N2) were minimal in recent weeks, and influenza B comprised the majority of detections since the middle of March.

    Influenza B had a greater impact on adults 65 years of age and older and young persons 5 to 19 years of age, compared to A(H1N1)pdm09 which mostly affected those 20 to 64 years of age.

    In the United States of America (USA), influenza activity continued to decrease slightly, although a late season increase in influenza B has stalled further decreases.

    Similar to Canada, the USA has seen an increased proportion of influenza B detections in recent weeks.

    The proportion of deaths attributed to pneumonia and influenza was below the epidemic threshold and the proportion of outpatient visits for ILI decreased from 1.6% to 1.4%, and was below the national baseline of 2.0%.

    In Mexico, influenza activity continued to decrease, and pneumonia rates were within expected levels for this time of year.

    Compared to the USA and Canada, Mexico experienced less of a late season increase in influenza B detections, leading to a swift decline in overall activity.

    The number of positive samples of influenza detected was very low, suggesting the influenza season is finished in the country and influenza activity has reached interseasonal levels.

    (...)


    Europe

    In Europe, overall activity declined. The majority of countries reported stable or decreasing trends and low intensity influenza activity.

    Influenza A(H3N2) was reported as the dominant virus currently in circulation, although A(H1N1)pdm09 continued to circulate at low levels as well.

    Very little influenza B was detected, and these were primarily from eastern Europe. In the north and south-west regions of Europe, detections continued to decline and activity remained low.

    Eastern Europe, which reported a slightly later start to the season, experienced decreased activity as well. The percentage of sentinel ILI/ARI specimens testing positive for influenza virus declined slightly, and was lower than levels seen during this week in the 2012-2013 and 2011-2012 seasons.

    Overall, there were consistently fewer sentinel specimens testing positive for influenza in the 2013-2014 European season than the previous one. With the exception of the countries in southern Europe, ILI rates were generally lower than previous season, suggesting th current season was less intense than the previous one.

    (...)


    Northern Africa and the Western and Central Asia region

    In Central and Western Asia, influenza activity remained low in most countries.

    The Islamic Republic of Iran and Turkey reported continued detections of influenza B virus, although at low levels .

    Influenza detections declined in Israel, and activity appears to nearing interseasonal levels.


    Eastern Asia

    In the Eastern Asian region, influenza activity continued to decline. Influenza B was the predominant virus in circulation, with low levels of A(H1N1)pdm09 and A(H3N2) also detected.

    In China, influenza activity continued to decline and approached interseasonal levels. The proportion of ILI specimens positive for influenza declined in both north and south China. Influenza B was predominant in both north and south China, with low detections of A(H1N1)pdm09 and A(H3N2) occurring as well.

    In Mongolia, ILI activity substantially decreased, and was below the country’s upper tolerance limit of 60%. The proportion of patients with pneumonia among the hospitalized and the proportion of ILI specimens positive for influenza also decreased. Similar to other countries in the region, influenza B was the predominant virus detected.

    In Japan, influenza activity was at interseasonal levels and minimal positive detections were found.

    In The Republic of Korea, influenza detections continued to decline, and influenza B was the primary virus in circulation. The overall proportion of patients who visited sentinel physicians for ILI fell below the national baseline of 12.1% to 9.7% for the first time this season since it went above the baseline in late December.

    Lao People’s Democratic Republic and Vietnam reported increased influenza activity in the beginning of April.


    Countries in the tropical zone

    Tropical countries of the Americas/Central America and the Caribbean

    The overall influenza activity in Central America and tropical areas of South America was at low levels.

    The French territories of Guyana and Guadeloupe previously announced the start of their season, and they continued to experience elevated ILI activity.


    Central African tropical region

    In the African tropical region, influenza activity was generally low, with the exception of Mauritius. Influenza B circulated in low levels in West Africa and Central Africa.

    Mauritius reported a decline in overall influenza activity although detections of A(H1N1)pdm09 viruses remained high.


    Tropical Asia

    In most South-East Asian countries, activity declined or remained low.

    Thailand reported decreases in activity, with ILI activity levels and influenza detections appearing to decline steadily in the past two weeks. Influenza A(H1N1)pdm09 and B viruses remained in circulation. During the current influenza season in Thailand a high number of severe cases of influenza was noted in comparison with previous season.

    Bhutan reported increased influenza activity in recent weeks, although the peak of activity appeared to have past and positive specimen levels declined. Detections were primarily of A(H3N2) and influenza B. ILI activity in Bhutan continued to increase despite some decrease in positive influenza specimens.

    India reported some low level circulation of influenza B virus in recent weeks.


    Countries in the temperate zone of the southern hemisphere

    In the Southern Hemisphere, influenza activity remained relatively low, with sporadic detections of influenza A(H1N1)pdm09, A(H3N2)and influenza B.

    In Australia, ILI activity increased compared to the previous two weeks, but remained at a low level.

    In the Pacific Islands, ILI activity was variable with an increase observed in several islands.

    (...)


    Source of data

    The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two weeks.

    The updates are based on available epidemiological and virological data sources, including FluNet (reported by the WHO Global Influenza Surveillance and Response System) and influenza reports from WHO Regional Offices and Member States. Completeness can vary among updates due to availability and quality of data available at the time when the update is developed.


    Link to web pages
    Contact fluupdate@who.int


    -
    ------
Working...
X