Animal parasites
Organisms adapted to living within or on body of another animal (host)
�Not capable of free-living existence
�Have a complex life cycle
�Live within intestinal tract and discharge eggs in feces
�Transmission favored by poor sanitation, high temperature, h
Protozoal Infections
�Microscopic, single-celled organisms
�Diseases: Malaria, amoebic dysentery, African sleeping sickness, cryptosporidiosis, toxoplasmosis, giardiasis, Chagas disease
�Common in temperate or tropical climates
Like bacteria, protozoa release toxins and enzym
Malaria:
-Plasmodium
- Mosquito bite
-Infection in RBC
-(Paroxysm) alternating coldness, rigor and fever
-All organ systems
-Joint pain, respiratory distress, convulsions.
Amebiasis
Entamoeba histolytica
Fecal-oral, anal-oral
intestines, liver
Bloody diarrhea, tenesmus, abdominal pain, liver abscesses
Genital tract trichomonad
�Caused by Trichomonas vaginalis
Giardiasis
Caused by Giardia lamblia, fecal-oral, infects small intestine; crampy abdominal pain
Toxoplasmosis
Caused by Toxoplasma gondii, fecal-oral, contaminated meat
brain
may infect fetus of pregnant woman and cause congenital malformations
Cryptosporidiosis
Cryptosporidium parvum; parasitizes the intestinal tract and can cause severe diarrhea
�Chagas disease
-Caused by the protozoan Trypanosoma cruzi
-Transmitted to humans by "kissing bugs"
-Most common in Central and South America
Ascaris
Large roundworm that lives within intestinal tract; eggs are discharged in feces
Pinworm
Small roundworm that migrates out of colon through the anus while the infected individual is asleep; deposits its eggs on the perianal skin; frequent in children and spreads through a family
Trichinella
Small roundworm that parasitizes humans and animals; most people become infected by eating improperly cooked pork
Tapeworms
�Long, ribbonlike worms that grow to a length of several feet and inhabit the intestinal tract
-Humans become infected by eating the flesh of an infected animal that contains the larvae of the parasite
Flukes
-Thick, fleshy, short worms with suckers that attach to the host
-Some live within the intestinal tract, liver, lungs, venous portal system; some (schistosomes) may infect skin
Arthropod Infections
�Transmitted by close physical contact and often spread by sexual contact
Scabies
�: Small parasite burrows in the superficial layers of the skin, where it lays eggs that hatch in a few days
Crab louse
�: Lives in anal and genital hairs; causes intense itching