Why will they not say it is waterborne if birds can be infected and move avian bird flu from water such as Arctic lakes?

Answer 1

Assuming the question is asking about H5N1, the highly pathogenic virus that can infect humans by transmission from infected birds, and that it is asking if that specific pathogen can be transmitted to humans in this way, the following applies. The term "waterborne" in relation to the transmission of pathogens is a method of transmission that is characterized and defined by their ability to transmit to humans when contaminated water is consumed. To date, there are no known cases of influenza A-H5N1 (the highly pathogenic form of Avian flu that results in death in over 50% of humans infected) spreading through human consumption of contaminated water. Therefore, international researchers, epidemiologists, and the World Health Organization (WHO), that monitor the transmission and occurrences of Infectious Diseases, including H5N1 Avian flu in humans, have not characterized this type of flu as waterborne.

All birds are known to be capable of hosting all subtypes of Type A influenza, the Type that includes the subtype of H5N1 viruses.

The only currently known and proven methods of transmission of this specific form of influenza to humans, however, are: direct contact with infected birds (or the feces, saliva or nasal discharges deposited by the infected birds onto environmental surfaces); direct contact with other contaminated environments (such as poultry coops and operations); through intermediate hosts such as pigs; or extremely rare isolated cases of human to human transmission in people who live in very close contact with each other (i.e., in the same households).

There are no known cases of Avian flu having occurred in humans as a result of transmission from wild waterfowl or wild wading/shore birds. These types of birds can be infected by the H5N1 virus and do transmit it to other birds, however, no humans have been found to have had this as the method of transmission so far. Most all cases in humans have been determined to be the result of direct contact with infected, sick or dead poultry, but not from wild birds.

Your concern about potential transmission from migratory waterfowl through the Arctic and northern lakes on their migration routes is valid. Various international governmental health agencies and infectious disease monitoring entities are watching this closely as a potential threat to humans. And, it would be feasible for the viruses to reassort (or mutate) into subtypes capable of this method of transmission (as there are known types of viruses that can be waterborne), although Type A H5N1 influenza is not among them to date.

There is also monitoring due to concern that Arctic lakes melting from global climate change and warming Arctic temperatures might release ancient influenza viruses to the environment. Present human populations are not expected to be immune to these ancient forms of influenza. However, the first identification and documentation of H5N1 in humans was in Asia in 1997. Therefore, while possible, it is a form influenza virus that is unlikely to be found frozen in Arctic lakes from thousands of years ago.

Another Answer:

There seems to be information in the article from National Institutes of Health below in the related links section that would indicate that avian flu can be waterborne. Obviously a child swiming in our Great Lakes or St. Lawrence river swallowing bird feces moved by birds or infected ballast water might contract influenza virus A. It is, therefore, not consistent, and not understood why they will not say it is waterborne.