Any of the susceptible birds can become infected with bird influenza virus when they have contact with contaminated nasal, respiratory, or fecal material from infected birds. Fecal-to-oral transmission is the most ordinary mode of spread between birds.
The spread of a lethal strain of bird flu in these past two years has sparked fears of a new pandemic. Although more than 200 people have contracted and are affected with the H5N1 virus, experts point out that cross-infection to humans is still relatively rare, and usually take place where people have been in close contact with infected birds.
Many scientists fear migrating birds to Europe and Africa might carry it but say it is hard to prove a direct link. Others say that farming methods and human lifestyle could be accelerating the spread.
Spread of bird flu in many countries But as H5N1 continues its journey through Europe and Africa from its original hotspot of south-east Asia, there is mounting concern that it might combine with a human strain to produce a mutation that is more dangerous and difficult to combat.
Of the few bird influenza viruses that have crossed the species barrier to infect humans, H5N1 has lead to the largest number of detected cases of severe disease and death in humans. In the current outbursts in Asia and Europe more than half of those infected with the virus have died. Most cases have taken place in previously healthy children and young adults.
However, it is probable that the only cases currently being reported are those in the most severely ill people, and that the full range of illness caused by the H5N1 virus has not yet been defined.
Spread of virus among the humans So far, the spread of H5N1 virus from person to person has been restricted and has not continued beyond one person. Nonetheless, because all influenza viruses have the capability to change, scientists are concerned that H5N1 virus one day could be able to infect humans and spread easily from one person to another.
Because these viruses do not generally infect humans, there is little or no immune protection against them in the human population. No one can predict when a pandemic might take place. However, experts from around the world are watching the H5N1 situation in Asia and Europe very closely and are preparing for the possibility that the virus might begin to spread more easily and widely from person to person.
That's a question being debated by experts, and although it may not seem important, the answer makes a big difference in understanding how to stop the spread of bird flu.
Some experts say that the main reason bird flu has spread from Southeast Asia to the Middle East, several areas of Africa and much of Europe is migratory birds.
Wild ducks are the standard reservoir for avian influenza viruses, meaning it's normal for them to carry various influenza viruses in their intestines. It normally does not affect the ducks themselves, but they can spread it to chickens and other birds.
Supporters of this theory cite the genetic consistency between the strain of H5N1 in the wild birds that died around Quinghai Lake, China in the spring of 2005 and the H5N1 found in dead birds found in Europe.
Some experts say that the bird flu virus is being spread mainly by people. On an international level, by smugglers of exotic birds and importers and exporters of chicken meat (often evading duties and tariffs). On the national level, by business people in the poultry industry transporting infected birds from one location to another.
At stake is a lot of money, planning and effort, because we need to adapt our tactics and strategies in the fight against bird flu to what will be most effective.
If bird flu is spread mainly by migratory birds, we need to monitor and restrict their contact with domestic poultry.
If bird flu is spread mainly by smugglers and transporters, we need to crack down hard on the smugglers and closely regulate and test chickens and eggs before transporting and selling them.
I'm no expert, but I'm putting forth the proposition that Indonesia is the perfect "laboratory" in which to test the validity of these two theories.
Indonesia is perhaps the most weirdly geographically shaped country in the world. It's rivalled by its neighbor to the north, The Philippines, and the Maldives. But it's 17,000 islands spread over thousands of square miles of ocean. On some islands, it shares space with other countries (East Timor, for example).
I'm sure that someone with more resources than I have could create a database to map the path of bird flu across Indonesia and then compare it with the two possible modes of transmission: wild birds and chicken transporters.
Then see which hypothesis best accounts for the facts:
Location of all islands plotted with longitude and latitude, along with all major cities, regional market centers and villages that have had bird flu cases.
Routes of migratory birds.
Location of all known human bird flu cases -- along with dates of infection.
Location of all known chicken bird flu cases -- along with dates of infection.
Location of all known wild fowl bird flu cases -- along with dates their bodies were found.
Genetic sequences of all known human bird flu cases -- together with comparisons with genetic sequences of other nearby infections (found in Thailand, China, Cambodia and Vietnam).
Genetic sequences of all known chicken bird flu cases -- together with comparisons from other Asian countries, plus those found in migratory birds in locations that are both come before and after the routes under which Indonesia lies.
Genetic sequences of all known wildlife bird flu cases -- together with comparisons from all those found in migratory birds in locations that are both come before and after the routes under which Indonesia lies.
All major transportation routes within Indonesia, including highways, airplane routes, ferries and boat routes.
All chicken transport routes.
Most common travel routes for day to day travel. Most people from the capital of Jakarta will travel only to rural areas where they have family or to vacation/resort spots. Most rural residents will travel only to Jakarta or to the nearest regional marketplace. (This is the norm in developing countries and with Indonesia extreme geography and ethnic diversity, it's very unlikely that anybody travels from rural province to rural province for pleasure.)
Most common business travel routes from province to province, especially transporting chicken and eggs.
Map all this data into some data mining software and it should soon clear whether bird flu -- in Indonesia, anyway -- is spreading through migrating birds or human transportation of chickens -- or both.
Richard Stooker has sinced written about articles on various topics from Bird Flu, Chess and Bird Flu. c 2006 by Richard StookerRichard Stooker is the author of and. Richard Stooker's top article generates over 12100 views. to your Favourites.