During the last few months there has been increasing attention worldwide to the possibility of a new flu pandemic caused by a recently isolated highly contagious form of avian influenza virus. It is generally accepted that a flu pandemic arises as a result of the appearance of a new virus strain. Such new viruses possess highly changeable surface antigens to which humans have no acquired immunity. Additionally, the general health status might be of importance. Thus, both virus and hosts actively participate in flu pandemic development. The extent of flu morbidity and mortality is determined not only by the genetic features of both participants, but also by external and internal conditions.
The present issue of Microbial Ecology in Health and Disease contains two articles presenting challenging opinions about mechanisms behind avian flu. In the first article, the well-known Russian scientist Boris Schenderov summarizes the state-of-the-art in the complicated scenario of microbe/microbe and host/microbe interactions. The impact of present knowledge is far wider than usually thought. If there is an intracellular viral quorum sensing system (and why should there not be one) it goes without saying that the ‘break-point’ of the system might be influenced by host factors. For decades, there has been no explanation of the well known observation that the Spanish Flu was far more virulent in young white men than in female or coloured people. A possible mechanism might be differences in ‘break-points’ for intracellular viral multiplication, governed by genetic factors as yet unknown.
When a pathogen has a respiratory or gastrointestinal entrance to the mammalian host, the first line of defence is the epithelial lining, together with the normal microflora in that compartment. Alterations in that microflora might create increased possibilities for entrance of a pathogen, and Schenderov mentions one important mechanism – alterations in proteases. Whatever the mechanism(s) might be, we need to know more, as strongly underlined by the author.
Based on the literature data that oxidative stress, local circulatory failure and nutrition factors play a very important role in the morbidity and mortality in several infections such as tuberculosis and HIV, Olav Albert Christophersen and Anna Haug are the first to focus on the possibility that morbidity and mortality in an upcoming pandemic of avian flu might be connected with the nutritional status of the host. They provide good references to several factors (some amino acids, vitamins, minerals and anti-oxidants, etc.) that obviously are of importance in creating a good defence against an infection.
Of course, several more factors could have been mentioned. The key point is that we start to think about how to build up a strong defence line against pandemic flu – especially in developing countries. Drugs are not the best answer – they are too expensive and, so far, we have too few. We have to prepare for the fight with the weapons we might have – and that means many, from increased knowledge about basic mechanisms to effects caused by protein-rich food enriched with certain factors, such as selenium.
Taken together, these two articles stress the importance of taking a broad view of the possibility of a new pandemic flu. The strategies outlined here are within reach and the messages given should indeed be given proper consideration.