Describe definitive host
mature forms of the parasite are present and usually reproducing
Describe intermediate host
immature parasites undergo various stages of maturation
what are the major routes by which humans acquire parasitic infections
ingestion, vector-borne transmission, direct contact and penetration of skin
what are the two morphological forms of protozoa that enter the body
trophozoite and cyst stage
describe the trophozoite morphologal form
feeding and reproducing stage which lives in host
describe the cyst stage morphological form
dormant and can survive in environment and is ineffective to new hosts
describe the transmission of Entamoeba
through drinking of water contaminated with feces
Describe the reservoir of Entamoeba
carried asymptomatically in the digestive tract of humans
what are the different disease types of Entamoeba
luminal amebiasis, amebic dysentery, invasive extra intestinal amebiasis
how is Entamoeba diagnosed
identification of microscopic cysts or trophozoites recovered from fresh stool or intestinal biopsies
How is Acanthamoeba and Naegleria transmitted
through cuts and scrapes, inhalation of contaminated water
Explain the severity of acanthamoeba and naegleria
both can be extensive and extremely harmful
What disease is caused by T. cruzi
Chagas disease
How is Chagas disease transmitted?
kissing bug
Where is Chagas disease usually found
Central and south america, california, Texas
what are the primary reservoirs of T. cruzi
opossums and armadillos
Contrast the life cycles of T. brucei and T. cruzi
in T. cruzi the bacteria is introduced into the bloodstream via scratching after a bite whereas in T. brucei the fly injects it into the bloodstream during a blood meal
What organ is affected by T. cruzi
spleen
What diseases is caused by T. brucei
african sleeping sickness
how is T. brucei transmitted
tsetse fly
What is effected by T. brucei
central nervous system
How are members of the genus Leishmania transmitted
via a sandfly
What are the three clinical manifestations of leishmania
cutaneous, mucocutaneous, visceral
describe cutaneous leishmania
large, painless skin ulcers form around bite wound
describe mucocutaneous leishmania
skin lesions enlarge to encompass mucous membranes of mouth, nose, or soft palate
describe visceral leishmania
fatal, macrophages spread parasite to liver, spleen, bone marrow, and lymph nodes
What are the reservoirs of Giardia intestinalis
person, animal, water
how is Giardia intestinalis transmitted
ingestion of affected water
what diseases is caused by Giardia intestinalis
Giardiasis: a waterborne GI disease
What are the three main stages in the life cycle of Plasmodium
liver phase, erythrocytic cycle, sporogonic phase
What diseases does Plasmodium cause
malaria
how do the symptoms of malaria relate to what is happening during the life cycle
in the erythrocytic cycle there is lysis of erythrocytes which causes anemia, weakness, and fatigue
What is the most common way to diagnose malaria
through identification of trophozoites and other stages in blood smears
What are some common methods of malaria control
limiting contact with mosquitos
What are the main reservoirs of toxoplasma gondii
wild and domestic mammals and birds
What is the definitive host of toxoplasma gondii
cats
How are humans infected with T. gondii
by ingesting undercooked meat containing the parasite. Also ingestion or inhalation of intoxicated soil
Which two populations are at greater risk for severe toxoplasmosis
people with aids and fetuses
What are the three main groups of parasitic helminths
cestodes, trematodes, nematodes
Regarding the presence of sex organs, what two groups are parasitic helminths classified
dioecious and monoecious
Describe dioecious
male and female sex organs are in separate worms
describe monoecious
each worm has both sex organs
What are the components of the generalized anatomy of a tapeworm
scolex, reproductive parts, strobila, proglottids
what are the 3 different proglottids and where are they located on the tapeworm
immature - near neck, mature - middle, gravid - end
Describe the common features of the life cycles of tapeworms that infect humans
Humans ingest in raw undercooked meat, it then attaches to mucosa of small intestines as a scolex
What are the definitive hosts of T. saginata and T. solium
humans
what is the intermediate host of T. saginata
cattle
What is the intermediate host of T. solium
swine
Regarding human infection, what is one key difference between these two species
humans can become accidental intermediate hosts of T. solium but not T. saginata
how is ascaris lumbricoides transmitted
ingested in water or on vegetables
What is the same about the life cycle of ascaris lumbricoides, hookworm, ad pinworm
it is swallowed
How are hookworms transmitted
larvae penetrate skin
How are pinworms transmitted?
Fecal-oral route
Eggs deposited on perianal skin
Describe the diseases caused by hookworms
anemia, iron deficiency, protein deficiency
Discuss the life cycle of intestinal nematodes
shed eggs into the lumen of the intestine. The eggs are consumed by the definitive host in contaminated food or water
Discuss the life cycle of filarial nematodes
mosquitos ingest microfilariae while feeding on humans. The microfilariae develop as larvae in the mosquito, and eventually migrate to salivary glands. When mosquito next feeds, parasites are injected into a new person