- The most common way people become infected is via
the fecal oral route through accidental ingestion of feces that is
contaminated with hymenolepis nana eggs. This infection is found in
all parts of the world with central Europe and Latin America being
hardest hit. Although rare, hymenolepiasis is usually found in the
south eastern portion of the U.S. H. nana infections are most
common in areas that have temperate climate zones.
- Children are the most vulnerable to this parasite
making nursery schools ideal environments for the spread of the infection.
An often referenced study in Zimbabwe conducted in 1994 gives some
insight into how the infection spreads. The study found that hymenolepiasis
is higher in urban areas than in rural areas. The study came to the
conclusion that intrafamily transmission was the primary mode of infection
in urban areas while in rural areas the infection was more prevalent
among younger, school age children.
- One estimate places the number of world-wide infections at 20 million,
but rates vary regional. In 1987, only 1% of American school children
were positive for the infeciton. In other parts of the world, such
as Argetina, the rates are much higher with 26% of school children
identified as having the infection.
- Unless a severe case is allowed to develop most infections are asymptomatic.
With extreme infections, however, a person may experience general
symptoms such as abdominal pain, diarrhea, headache, and overall weakness.