Thursday, June 02, 2016

Influenza Picking Up In the Tropics & Southern Hemisphere


As we discussed last April in It's Always Flu Weather, if it isn't flu season where you are, it almost certainly flu season somewhere else in the world.

As the Northern Hemisphere's flu season fades into hazy memory, influenza is already on the rise in the Southern Hemisphere, and flu circulates more or less year round in the tropics (often peaking during their rainy season).

A few weeks ago, in An Early Start To South America's Flu Season?, we looked at reports of increased flu activity in Argentina and Bolivia and the declaration of an epidemiological alert by the Bolivian Health Ministry.

Before that, in April we looked at reports of early flu in Brazil (see  Unseasonable Seasonal Flu In São Paulo), which has compounded concerns over the upcoming Olympics.

Today, in Panama (where the rainy season starts in May, and runs through mid-August), newspapers are carrying similar reports of heavy flu activity (see Epidemiological alert for influenza), and the Panamanian MOH has issued the following statement.

Wednesday, June 1, 2016
The Health Ministry informs citizens that with the arrival of rains and the circulation of influenza A H1N1pdm09 and other respiratory viruses like the common cold and flu in the country, so the population is recommended to take measures for prevention and control such as:

  • Wash hands often.
  • They also have to cover your mouth and nose when sneezing or coughing (use handkerchief or elbow angle to retain the droplets ejected).
  • If respiratory symptoms such as coughing, sneezing, runny nose , fever, difficulty breathing, should go to the health center or nearest polyclinic immediately.
  • Do not self-medicate, do not take anti - inflammatory drugs (NSAIDs)
  • Do not go to places with high concentration of people, have symptoms.
  • people with influenza or other respiratory disease should not visit patients in. hospitals, clinics, nursing homes, prisons and other
  • Following recommendations from WHO / PAHO vaccines are applied to the groups most at risk such as children under 5 are years, over 60, pregnant women, people with chronic diseases and health personnel. For these groups vaccines are available for free at all health facilities CSS and MINSA.
Signs and symptoms caused by influenza include fever, cough, sore throat and runny nose in children can cause otitis media, nausea and vomiting. The duration is approximately 3 to 7 days. Complications from influenza virus most common are: pneumonia, bronchopneumonia or bronchiolitis, sinusitis, otitis media; these conditions can worsen and lead to death.  

MINSA very responsibly notes that in Panama there is currently no epidemic, we have a warning for the circulation of influenza virus AH1N1pdm09, which can cause serious evolution in the population at risk .

Despite the hyperbolic headlines, and almost daily accountings of flu deaths across South America, influenza is - and always has been - a serious illness capable of producing significant morbidity and mortality. 

Something the media, and the public, seem to forget during the off season.
While we continue to watch the developments in South and Central America, there is little evidence right now to suggest they are seeing anything more than the start of a moderately strong H1N1 flu season.

Influenza is highly unpredictable, however, and so we keep close watch on these sorts of reports.  

The World Health Organization has released their bi-weekly global flu surveillance report, and they note the increasing flu activity in parts of South America and the tropics.

30 May 2016, - Update number 264, based on data up to 15 May, 2016


Influenza activity in the northern hemisphere continued to decrease with a predominance of influenza B virus reported. In temperate countries in the southern hemisphere, influenza activity started to increase slightly in South America and South Africa, but remained low overall in most of Oceania.
  • In North America, influenza activity continued to decrease while the proportion of influenza B virus detections increased compared to previous reporting periods.
  • Influenza activity continued to decrease in Europe and temperate Asia with a predominance of influenza B virus activity.
  • In Africa, influenza activity was generally low with influenza A virus detections reported in Western Africa and influenza A and B virus detections reported in Eastern Africa.
  • In Central America and the Caribbean countries, influenza and other respiratory virus activity remained generally low, although levels of A(H1N1)pdm09 virus activity continued to increase in El Salvador, Guatemala and Panama. Active circulation of influenza A(H1N1)pdm09 was also reported in Suriname. In Jamaica, severe acute respiratory infection (SARI) activity remained above the threshold and an increase in pneumonia cases was observed.
  • In tropical South America, increased influenza A(H1N1)pdm09 activity was reported in Bolivia. SARI activity was elevated in Ecuador together with a high proportion of samples positive for respiratory syncytial virus (RSV) and influenza A(H1N1)pdm09 virus. Peru reported increased RSV detections.
  • In tropical countries of South Asia, influenza activity was generally low but several countries reported increased influenza virus detections.
  • In temperate South America, influenza-like illness (ILI) activity increased in recent weeks above seasonal thresholds. Increases in RSV activity in the region and influenza A detections in Argentina and Uruguay were also reported.
  • In the temperate countries of Southern Africa and Oceania, influenza virus activity remained low. Some islands in the Pacific reported increased ILI activity. Influenza activity started to increase in South Africa with mainly influenza B viruses detected.
  • National Influenza Centres (NICs) and other national influenza laboratories from 90 countries, areas or territories reported data to FluNet for the time period from 02 May 2016 to 15 May 2016 (data as of 2016-05-27 03:46:29 UTC). The WHO GISRS laboratories tested more than 63813 specimens during that time period. 6224 were positive for influenza viruses, of which 2104 (33.8%) were typed as influenza A and 4120 (66.2%) as influenza B. Of the sub-typed influenza A viruses, 938 (79%) were influenza A(H1N1)pdm09 and 249 (21%) were influenza A(H3N2). Of the characterized B viruses, 268 (25%) belonged to the B-Yamagata lineage and 804 (75%) to the B-Victoria lineage.

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