Influenza viruses are the causative agent of influenza infection, an acute highly contagious respiratory illness that each year results in high levels of morbidity and mortality.  The Maryland Department of Health (MDH) Laboratory routinely conducts testing of seasonal influenza A and influenza B viruses from healthcare providers from across the state that are widely circulating in the United States. Statewide influenza monitoring by the Maryland Department of Health is important because it allows for a better understanding of viruses that are currently circulating in our communities, the detection of antiviral drug resistance, and in rare instances, the identification of newly emerging, highly-pathogenic influenza viruses that could potentially cause worldwide pandemics. Such was the case in 2009, with the emergence of the influenza A H1N1 virus. Since 2003, two strains of avian influenza (H5N1 and H7N1) have emerged from Asia and have sporadically caused severe illness in patients with direct contact with infected poultry or  other affected species; however, transmission of these strains between humans have been limited.

During a recent outbreak of highly-pathogenic avian influenza (HPAI), it was discovered that dairy cows are susceptible to HPAI infection, with high viral loads detected in unpasteurized milk samples. Epidemiological surveillance has revealed that other wildlife species, such as felines, rodents and bears have been infected with HPAI; however, wild and domesticated flocks of birds are more widely susceptible to infection, and therefore represent the highest risk to humans. 

Newly emerging avian influenza viruses have the potential to be highly virulent and could rapidly evolve into strains that could be transmitted from human to human. As a result, the Maryland Department of Health has the ability to test for Influenza A/H5 (Asian lineage) and Influenza A/H7 (Eurasian Lineage) for patients who meet epidemiological criteria, such as those who have come into contact with infected species or individuals, or those who have recently traveled to locations with known avian influenza activity. Additionally, MDH monitors seasonal influenza testing for untypeable or newly emerging strains.

For​ more information regarding novel avian influenza infection of humans, please visit the CDC website: https://www.cdc.gov/bird-flu/index.html