Associations between Meteorological Parameters and Influenza Activity in Berlin (Germany), Ljubljana (Slovenia), Castile and León (Spain) and Israeli Districts

BackgroundInfluenza is a global transmissible disease. Its dynamics is far better understood in temperate climates than in the tropics. We aim to close this knowledge gap between tropical and temperate regions by showing how the influenza seasonality evolves in Brazil, a tropical country that encompasses a wide range of latitudes and six climatic sub-types.MethodsWe analyzed a state-level, weekly Syndrome of Acute Respiratory Disease (SARI) incidence data ranging from 2010 to 2016. We combined two techniques hierarchically: first the wavelet decomposition technique to detect annual periodicity and then circular statistics to describe seasonal measures of the periodic states.ResultsWe found significant annual periodicity in 44% of the states. For these, we calculated several seasonal measures such as the center of gravity or mean timing of activity. The relationship between the seasonal signatures and latitude was clear and statistically significant. States with seasonal signature are clustered along the coast. Most Amazonian and Central West states exhibit no seasonal behavior. Among the seasonal states, influenza starts in Northeast region, spreading southbound.ConclusionsOur study advances the comprehension of influenza seasonality in tropical areas and could be used to design more effective prevention and control strategies.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3484-z) contains supplementary material, which is available to authorized users.

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“…Most of them associate it to climatic variables like temperature, precipitation, humidity or hours of sunshine [5, 15, 17, 18, 20, 40]. …”

Section: Discussionmentioning

confidence: 99%

Seasonal dynamics of influenza in Brazil: the latitude effect

2018

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“…Bahrain, Qatar and Oman were the southernmost countries included in our analysis; in fact, they are situated at roughly the same latitudes as countries which are characterized by less defined influenza seasonality and multiple epidemic peaks, such as India and southern China. Climatic parameters, such as absolute humidity, temperature and rainfalls, shape influenza seasonality, both in temperate and tropical climate countries, and are likely to be the main driver of influenza seasonality in the Middle East and North Africa as well, although only a few studies have been conducted so far in this region. Population movements (eg annual Hajj pilgrimage, migrants and nomadic populations) might also contribute to determine influenza seasonality in some countries and the spread of epidemics across the region.…”

Section: Discussionmentioning

confidence: 99%

Epidemiology of seasonal influenza in the Middle East and North Africa regions, 2010‐2016: Circulating influenza A and B viruses and spatial timing of epidemics

Caini

Séblain

Cıblak

et al. 2018

Influenza Resp Viruses

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BackgroundThere is a limited knowledge regarding the epidemiology of influenza in Middle East and North Africa.ObjectivesWe described the patterns of influenza circulation and the timing of seasonal epidemics in countries of Middle East and North Africa.MethodsWe used virological surveillance data for 2010‐2016 from the WHO FluNet database. In each country, we calculated the median proportion of cases that were caused by each virus type and subtype; determined the timing and amplitude of the primary and secondary peaks; and used linear regression models to test for spatial trends in the timing of epidemics.ResultsWe included 70 532 influenza cases from seventeen countries. Influenza A and B accounted for a median 76.5% and 23.5% of cases in a season and were the dominant type in 86.8% and 13.2% of seasons. The proportion of influenza A cases that were subtyped was 85.9%, while only 4.4% of influenza B cases were characterized. For most countries, influenza seasonality was similar to the Northern Hemisphere, with a single large peak between January and March; exceptions were the countries in the Arabian Peninsula and Jordan, all of which showed clear secondary peaks, and some countries had an earlier primary peak (in November‐December in Bahrain and Qatar). The direction of the timing of influenza activity was east to west and south to north in 2012‐2013 and 2015‐2016, and west to east in 2014‐2015.ConclusionsThe epidemiology of influenza is generally uniform in countries of Middle East and North Africa, with influenza B playing an important role in the seasonal disease burden.

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“…6 Several studies have assessed the effects of weather on influenza activities in different climatic regions. 13 , 14 , 44-46 A series of studies by Soebiyanto et al [44][45][46] showed that specific humidity was strongly associated with influenza activity across temperate and subtropical climates. Tamerius et al explored the associations between the timing of seasonal influenza epidemics and climate variability in 78 study sites sampled globally, suggesting that "cold-dry" and "humid-rainy" conditions tended to be associated with influenza seasonality worldwide.…”

Section: Introductionmentioning

confidence: 99%