Download Giardia lamblia

Giardia lamblia
My name is Giardia lamblia and I am a microscopic parasite with a soiled reputation and
a dirty story to tell. My presence in the human body leads to infection of the small intestine,
referred to as Giardiasis, more commonly known as a contagious form of diarrhea. I am the
most frequent cause of parasitic gastrointestinal disease, contributing to the approximately 2.5
million people who become infected with Giardiasis annually in the United States alone. I enjoy
meeting new digestive systems, but it is equally important for me to maintain contact with
previous acquaintances, so 20% of the world’s population is chronically infected with me.
I take on two different forms to infect humans. When I am active inside the body, I am a
trophozoite, and when I am resting outside the body, I am a cyst. In order to infect a person, I
must be swallowed first as a cyst. Soon after, I am stimulated by stomach acids to develop into a
disease-causing trophozoite. Once in trophozoite form, I attach to the lining of the small
intestine where I reproduce more trophozoites that are then carried down the intestine via the
fecal stream. I revert back to cyst form while in the lower intestine and am expelled from the
body in feces. I am always present in the feces of infected persons, so contamination by or
contact with their feces can spread the infection to others. For this reason, most of my time is
spent in developing countries that are overcrowded and plagued by inadequate sanitation and
water quality control. However, I am also the most common cause of waterborne epidemics of
diarrhea in the United States, whether the carriers are animals or humans.
Once infected, I inflict various symptoms on the body, including sudden explosive,
watery, foul-smelling diarrhea, tremendous gas, stomach pain, bloating, nausea, tiredness,
vomiting and loss of appetite. If not treated with drugs, my infection can last for long periods
and result in chronic symptoms, such as impaired digestion, lactose intolerance, sporadic
diarrhea, fatigue and considerable weight loss.
Reference: http://www.medicinenet.com