[pct-l] Giardia

[Jeffrey Olson]

The prevalence of giardia seems to be relatively small. I hiked until 
the late 80s never filtering water or using iodine. When filter 
manufacturers started producing filters they needed a market, and hence, 
the big scare about giardia. As Brick said, 4% - 7% of us are carriers.

The article below says, "The CDC estimates that as many as 2,500,000 
cases occur in the US, or about one for every 100 persons—every year."

"Since cysts that “winter over” in the Sierra Nevada are either in 
liquid water for considerably more than 2 to 3 months, or exposed to 
freezing temperatures, few—if any—survive the harsh Sierra winters. So, 
except for pollution by winter visitors and non-hibernating animals, 
/Giardia/ contamination in the high country must begin essentially anew 
each spring."

"Recall that San Francisco water can contain a concentration approaching 
0.12 cysts per liter, a figure now seen to be higher than that measured 
anywhere in the Sierra."

"If you are unlucky enough to get giardiasis with symptoms, the symptoms 
will probably be gone in a week or so without treatment. You may still 
be harboring the cysts, however, and can unknowingly spread the disease. 
Thus, practicing commonly recommended wilderness sanitary 
habits—defecating 100 feet from water, burying or packing out feces and 
toilet paper, washing before handling food, etc.—is an excellent idea."

"The water that wilderness travelers are apt to drink, assuming that 
they use a little care, seems almost universally safe as far as Giardia 
is concerned. The study referred to earlier,^3 in which the researchers 
concluded that the risk of contracting giardiasis in the wilderness is 
similar to that of a shark attack, is telling. What they did find is 
that /Giardia/ and other intestinal bugs are for the most part spread by 
direct fecal-oral or food-borne transmission, not by contaminated 
drinking water. Since personal hygiene often takes a backseat when 
camping, the possibility of contracting giardiasis from someone in your 
own party—someone who is asymptomatic, probably—is real. Recalling that 
up to 7 percent of Americans, or up to 1 in 14, are infected, it is not 
surprising that wilderness visitors can indeed come home with a case of 
giardiasis, contracted not from the water…but from one of their friends."

      /“Given the casual approach to personal hygiene that characterizes
      most backpacking treks, hand washing is likely to be a much more
      useful preventative strategy (for Giardia) than water
      disinfection!//^ //^[viii] / <#_ftn8>/ This simple expedient,
      strictly enforced in health care, child care, and food service
      settings, is rarely mentioned in wilderness education materials.”
      ^3 / 

Hygiene seems to be the biggest factor, and yet, who knows why any one 
person gets it. The article below is interesting...

Jeff, just Jeff
Martin, SD

http://lomaprieta.sierraclub.org/pcs/articles/giardia.asp