In southern Brazil, these subtypes co-circulate in subjects with homogeneous demographic and clinical features, enabling a better understanding of the role of HIV-1 subtypes on the characteristics of infection.
H3N2 and H1N1 influenza A viruses have co-circulated in the human population since the re-emergence of H1N1 in 1977 increasing the possibility of genetic reassortment.
The chronological phylogeny for Canada revealed that five distinct A/H1N1pdm viral lineages entered and co-circulated in Canada in 2009.
There are four antigenically distinct RNA viruses that can cause the disease, and in Brazil, three Dengue serotypes (DENV-1; DENV-2 and DENV-3) have co-circulated in several areas and caused some severe Dengue epidemics [2].
Genetic analysis showed that wholly contemporary human-like H3N2 viruses and double-reassortant viruses containing genes from contemporary human (PB2, PB1, PA, HA, NP, and NA) and avian H5 (M and NS) viruses were co-circulating in pig populations.
During three consecutive winter seasons, two separate highly conserved MP genotypes co-circulated in similar proportions.
For example, Asia-1 and −2 strains have co-circulated in China and Japan; meanwhile, Arctic, EW, and other EU-1/SA-1 stains have co-circulated in several European countries.
These results suggest that ≥2 influenza A virus H7 subtypes co-circulated in eastern Asia during that period.
In 1999, all four DENV types co-circulated in the island resulting in 4,993 reported cases.
In the third season 2012/13, all three types/subtypes co-circulated in similar proportions (34 % A(H1N1 pdm2009, 31 % A(H3N2), and 35 % B).
Although both genogroup B and genogroup C HEV71 strains co-circulated in Sarawak, the predominant genogroup in both the HEV71 outbreaks of 2000 and 2003 was genogroup B.
