Infectious Disease Epidemiology Program
Giardiasis summary
Giardiasis is sometimes known as “beaver fever” because beavers (as well as dogs, cats,
horses and cows) are major reservoirs for the parasite that causes the infection. The parasite lives
in the intestines of infected humans and animals and when expelled through the feces can contaminate
water and ground surfaces. The beaver feces can infect ponds and streams and if hikers or others drink
water in the wild without proper treatment they may become infected. Young children in child care or
pool settings who are prone to sucking on toys or swallowing water are also at higher risk.
Giardiasis
is the most common infectious diarrheal illness reported in Maine. There were 197 cases reported in
2007, a slight increase from 2006. All of the counties reported cases with the highest rates in Franklin
(26.7 per 100,000 population), Somerset (25.2 per 100,000 population), and Cumberland (22.2 per 100,000
population).
Giardiasis tends to occur more frequently in the summer and fall months with twice the
number of cases identified in August and September than other months of the year. There was a near
even split by gender with fifty-one percent of cases being female. The median age was 37 years old.
Individuals can prevent this illness by not drinking from untreated water sources such as streams
and lakes. Increased attention to proper sanitation and hygiene in public water recreational facilities
can help to reduce the transmission of this infection.
