( t. Brazil is nearly the same size as ...)Researchers Find Surprising Pattern of Influenza Spread in South,America and Tropics,Health

Brazil is nearly the same size as the United States. However, most of Brazil's territory lies in the tropical belt. This aspect makes the study valuable since less is known about the circulation of influenza viruses at these latitudes and how epidemics bridge and annually alternate between both hemispheres following the winter seasons.

Given the range of latitude encompassed by Brazil which crosses the equatorial and the southern tropic lines and using sophisticated mathematical analytical tools, the researchers studied the mortality data of influenza and pneumonia from two decades, together with laboratory confirmed data from recent years.

Both sets of independent data sources converged to show that, surprisingly, in Brazil influenza epidemics do not spread from where the highest human population densities are found, but rather from the equator towards more populous regions of the Southeast and South of Brazil.

The study, supported by FIC, results from a collaboration among researchers in different parts of the world. Study authors are Wladimir J. Alonso (FIC), Cécile Viboud (FIC), Lone Simonsen (NIAID), Eduardo W. Hirano (Mechanical Engineering Department, Universidade Federal de Santa Catarina, Florianópolis, Brazil), Luciane Z. Daufenbach (Secretariat of Health Surveillance, Ministry of Health, Brasília, Brazil), and Mark A. Miller (FIC).

FIC <http://www.fic.nih.gov>, the international component of the NIH, addresses global health challenges through innovative and collaborative research and training programs and supports and advances the NIH mission through international partnerships.

NIAID <http://www.niaid.nih.gov> is a component of the National Institutes of Health. NIAID supports basic and applied research to prevent, diagnose and treat infectious diseases such as HIV/AIDS and other
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