If that writer really has accurate information, it's a shocking figure. If 50% of the population carries the bacteria then it almost makes it pointless to test for Lyme, because as we know only a small fraction of those 50% are sick. The conclusion from this number would be that Lyme isn't the reason people get sick, there must be some other factors.
I live in Michigan. Independent testing 10 years ago showed among symptomatic and asymptomatic people around the Great Lakes ( Minnesota, Wisconsin, Michigan, Ontario Canada, )
90% tested positive on highly specific borellia Western Blot testing. The study is on the ILADS site.
People are getting MORE ill with chronic diseases ( like " probably ALS" or " something Autoimmune" ) than past generations.
I know people who died at 65 from chronic illness with no name, while thier mothers and aunts/ uncle's are Healthy at 85-100. This is SHOCKINGLY common- people from 40-60 more disabled than thier elderly parents.
It is my case.
Much has to do with how woodlands were managed in the 1960-70s, allowing for a POPULATION EXPLOSION of BORELLIA- CARRYING ANIMALS.
This was the case in the Northern US- when I lived in Sweden, it was the same practice, and they have a date as high as my state in the US.
I'm not sure how Central Europe managed forests and deer populations.
I have learned MUCH from Veterinarians, who know about disease epidemics decades before medical Drs.
The best Indicators of infection and disease rates, are to look at animal disease maps ( dogs, horses, cattle, sheep; but esp dogs and horses).
THOUGH IT'S KNOWN ( talk to a Veterinarian or Epidemiologist) almost nothing is written about TRANSMISSION BY BIRDS. They have carried BORELLIA- around the world. It's endemic among forestry workers in Australia. It's in Japan.
MANY PEOPLE HAVE GOTTEN IT IN NEW YORK CITY, WALKING IN CENTRAL PARK.
YOU DON'T HAVE THE BE IN THE WILD.
I am happy for those who get SWIFT treatment in the first year; though that is no guarantee it won't progress.
ALL OF US IN THIS AREA WHO HAVE IT, HAD weeks of ANTIBIOTICS AS CHILDREN OR TEENS. Acne treatments for 1-2 years should eradicate it.
Genetics, methylation, number of exposures, increasing virulence of the bacteria - all seem to have a correlation with re emergence, and severity.
So, yes the exposure/antibody production can be as high as 50%, or higher.
Historically, in the past almost EVERYONE in Europe tested positive for TB, and was exposed. Not all were Chronically Ill or died, but all were exposed and most were carriers.
Same with the plague, Influenza, etc.