Art,
Was hoping you would address your statement that histoplasmosis spores can be made airborne by thunderstorms and aircraft breaking the sound barrier.
In terms of the elderly folks who contracted and the two who died my question would relate to how many times in their lifetime were they exposed to histoplasmosis from bird droppings and other environmental scenarios? Just in terms of a long life many folks have swept up bird droppings, worked in barns, farms, on bridges or highway structures with heavy bird and yes bat droppings on them.
In order to tie in the bat guano in their own home to them contracting and dying of histoplasmosis it would take them having been tested prior to being exposed (testing clean) and then being tested post exposure to bat droppings as described to show any tie to that being the cause of their contracting it and their ultimate demise in the case of the 2.
Like any disease, airborne materials, parasites, etc... it takes a clear line of testing to prove how the epidemiological cycle took place.
Example, I see companies tear down gas station canopies all the time to put new ones up, most have heavy pigeon use and the employees of these canopy companies are often completely exposed to all airborne materials.
How many do you think are tested before they get hired to see if they have a positive histoplasmosis result, versus say 10 or 20 years from now a chronic infection results in their ultimate result of histoplasmosis infection and they look the last thing they did, not what they were doing 10 or 20 years ago.
If the elderly folks in the example you gave told you they just crawled through their attic that was full of droppings and then acutely became ill and died, we'd have a pretty good smoking gun though still possible they got it elsewhere. But did they get it from guano sealed inside a space that wasn't able to put histo spores in their living quarters? If so I'd be looking elsewhere for where the infection came from. Maybe they fed birds at a feeder and when they cleaned up the feeder or under it they were exposed to airborne spores that way and contracted it. Who knows, but extrapolation versus morbidity mortality results and case studies that are published is harder to believe in.
The persons most at risk from histo would pertain to literally any disease or virus. Even the old run of the mill flu is on that same level as would be things like salmonella infection from the little chicks kids adopt at easter and newborn rabbits during the same holiday.
I agree anyone going to offer folks guano mitigation or any mitigation of droppings or where other issues may be found should know what they are doing.
That said how many do get training of any kind on how to do it versus reading documents from CDC or OSHA or some other safety entity with written protocol or directions.
Even these are based only on the best available information at the time, not on total reality as often they aren't studied far enough due to lack of interest, lack of funding and lack of concern versus other serious illnesses and disease.
Folks can die from so many low grade simple things, the flu, food poisoning, basic infection from an open wound or scratch or sore. Since it is estimated that so many people have been exposed to histo (as Dave's statement referred to above), now lets imagine histoplasmosis is very very very serious, don't we believe the death toll would be far far greater and the attention on it would be extremely high. We'd know that organism inside and out and testing would be mandatory at your doctor due to it's persistence in the environment related to birds, let alone bats.
Like all things, I would agree "take the time to learn the facts before dispensing advise to clients," I think as well that knowing the true level of risk to a client is important so that it isn't overstated or understated and histoplasmosis is used as a scare tactic often enough that I hear of folks being told they can die from 5-10 bat droppings on their front stoop if they don't hire a company to do a complete insulation tear out, mitigation and ultimately exclusion....
I've worked with plague, rabies, tuberculosis, pseudorabies, brucellosis and a string of others I fail to think about anymore.
The world of zoonotic disease is an important part of a dialogue with many clients, however the knowledge base varies even wider than the skill sets in our industry and in health departments and in game and fish departments and every other entity who uses some of what they hear, some of what they read and then some just off the cuff what sounds sensible.
As long as people don't overstate the risks to sell jobs I don't have a big problem, but if someone is making what sound like scientific statements without scientific publications to refer to, to me that falls into the circular file category.
No one can know it all, but I'm trying hard to picture the graduate student sitting in someones guano filled attic with some type of monitoring devices waiting for a thunderstorm, or a jet to fly over so they can record airborne materials.... So if this is published fact on this organism, I'd seriously like to see it...
The latest rendition with updated info from CDC's website - a good read and watch how much emphasis is placed upon birds and the environment (tilling soil, etc..)
http://www.cdc.gov/niosh/docs/2005-109/pdfs/2005-109.pdf