Thursday, January 17, 2008

The Virus My Friend, Is Blowin' In The Wind


# 1487



Well, perhaps not.  But that's the story coming out of India.


The desire to place the blame for bird flu outbreaks on some other entity runs strong in many places, but apparently no where stronger than in India, where an animal husbandry official has come up with an `unusual explanation' for how the virus ended up in West Bengal.  




Bangladesh identified as origin of West Bengal bird flu

17 Jan 2008, 1802 hrs IST,PTI


SILIGURI: Bangladesh has been identified as the source of outbreak of bird flu in south Dinajpur, one of the two affected districts in West Bengal, a senior Animal Husbandry official said.


"The germs were brought by winds blowing from Bangladesh," Assistant Commissioner of the Central Animal Husbandry department Sujit Dutta said in Balurghat, the headquarters of south Dinajpur.


Dutta said that the Centre is constantly monitoring the situation in the district.


The BSF guarding the Indo-Bangla border in the district has been alerted to ensure that no poultry products could enter from Bangladesh, Inspector General of Police (North Bengal) R J S Nalwa said.


The administration of Siliguri subdivision of Darjeeling district has decided to immediately stop import of chickens, chicks and eggs to Siliguri from outside and continue checks for sick birds, SDO Smita Pandey said.



This statement, that the virus was `brought by winds blowing from Bangladesh', I'm certain, plays well among the locals. 


But, Is it possible?


Well, I'm reluctant to call any theory `impossible'.  History has shown that many things previously thought to be impossible are today accepted as fact.


There have been some studies on dust, carried across the Atlantic Ocean by the trade winds, that suggest some types of microbes might ride the dust particles and settle thousands of miles away. 


The following excerpts come from an article published by the Guardian Unlimited in 2004 called It's an Ill Wind.



Tests on airborne dust samples collected in the Caribbean were found to contain infectious spores of the fungus. Scientists suspect the spores had been carried on the wind from Africa, before landing on the ocean surface, sinking and infecting the sea fans. Enough had built up on the ocean floor for the disease to spread. Since then, several outbreaks have been linked to dust clouds.


It could help to explain why the Caribbean has some of the highest rates of asthma in the world. With so much evidence implicating dust clouds as a health threat, Kellogg and her colleagues decided to carry out an audit on dust, initially that coming out of Africa. Since a single gram of soil can contain upwards of 10,000 bacteria, it was no simple task.



From air monitoring stations set up in the Virgin Islands, and from samples taken in Africa, Kellogg found that not only were microbes able to travel the thousands of miles from Africa, but that nearly a third of those that survived were known pathogens.



Kellogg has so far identified at least 170 different bacteria and 76 types of fungus in airborne dust collected on the Virgin Islands. Among them are Cladosporium and Aureobasidium fungi, which can cause skin and respiratory infections, and several bacillus species that can cause gastrointestinal illnesses and septicaemia.



So `impossible' may be too strong a stance.  There are scientists studying the possibility that some infectious diseases could be transported by dust.  Most of these, however, are bacteria and spores from fungus.


Fungus spores are notoriously hard to kill, unlike the far more fragile influenza virus.  They are less susceptible to desiccation, UV exposure, and temperature extremes.


I have a much harder time accepting that fragile influenza viruses could ride on miniscule dust chariots across the sky.  


Maybe it's not impossible.


But I am extremely dubious.