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Four types of influenza viruses (A-D) have been confirmed (https://www.cdc.gov/flu/about/viruses/types. htm). The recently discovered influenza D virus is thought to cause respiratory diseases primarily in cattle and to a lesser [...]

A study was conducted to evaluate the significant mortality and nosocomial transmission associated in patients with oseltamivir-resistant influenza A(H1N1) virus. Results indicated that seasonal oseltamivir-resistant influenza A(H1N1) viruses are transmitted and present a high-risk of mortality among high-risk patients.

Influenza A viruses are highly infectious respiratory pathogens that can infect many species. Birds are the reservoir for all known influenza A subtypes; and novel influenza viruses can emerge from birds and infect mammalian species including humans. Because swine are susceptible to infection with both avian and human influenza viruses, novel reassortant influenza viruses can be generated in this mammalian species by reassortment of influenza viral segments leading to the 'mixing vessel' theory. There is no direct evidence that the reassortment events culminating in the 1918, 1957 or 1968 pandemic influenza viruses originated from pigs. Genetic reassortment among avian, human and/or swine influenza virus gene segments has occurred in pigs and some novel reassortant swine viruses have been transmitted to humans. Notably, novel reassortant H2N3 influenza viruses isolated from the US pigs, most likely infected with avian influenza viruses through surface water collected in ponds for cleaning barns and watering animals, had a similar genetic make-up to early isolates (1957) of the H2N2 human pandemic. These novel H2N3 swine viruses were able to cause disease in swine and mice and were infectious and highly transmissible in swine and ferrets without prior adaptation. The preceding example shows that pigs could transmit novel viruses from an avian reservoir to other mammalian species. Importantly, H2 viruses pose a substantial risk to humans because they have been absent from mammalian species since 1968 and people born after 1968 have little preexisting immunity to the H2 subtype. It is difficult to predict which virus will cause the next human pandemic and when that pandemic might begin. Importantly, the establishment and spread of a reassorted mammalian-adapted virus from pigs to humans could happen anywhere in the world. Therefore, both human and veterinary research needs to give more attention to potential cross-species transmission capacity of influenza A viruses. Keyswords: Swine, influenza A virus, mixing vessel, genetic reassortment, human pandemic, INTRODUCTION The ecology of influenza A viruses The presence of all subtypes influenza A viruses in wild aquatic birds poses serious health risks to a wide range of animal species. [...]

We report the first large-scale surveillance of avian influenza viruses in water birds conducted in Africa. This study shows evidence of avian influenza viruses in wild birds, both Eurasian and [...]

We studied 7 influenza (H5N1) viruses isolated from poultry in western Siberia and the European part of the Russian Federation during July 2005-February 2006. Full genome sequences showed high homology [...]

We used a regression model to examine the impact of influenza on death rates in tropical Singapore for the period 1996-2003. Influenza A (H3N2) was the predominant circulating influenza virus [...]

This recommendation relates to the composition of vaccines for the forthcoming influenza season in the northern hemisphere (November 2005 to April 2006). A recommendation will be made in September 2005 [...]

To the Editor: Influenza is globally the most economically important respiratory disease in humans, pigs, horses, and fowl (1). Influenza virus is known for its continuous genetic and antigenic changes, [...]

Most avian influenza viruses remain unique to their hosts and pose no threat to human life, however, under the right circumstances, some can jump from animals to humans. The few autopsies performed on human victims of H5N1 have revealed that the viruses lodges deep in the crevasses of the lung tissue, not in the major airways as would be the case in an infectious flu.

Adults presenting to GP surgeries with lower respiratory tract infections predominantly have a viral illness, most commonly caused by rhinoviruses and influenza viruses. Lower respiratory tract infections are a common [...]