Parasitology Flashcards
What is Sporogony?
Where does Sporogony occur?
Sexual reproduction of the parasite
Insect (definitive host)
What is Schizogony?
Where does Schizogony occur?
Asexual reproduction of parasite
Mammal (intermediate/dead-end host)
What is the plasmodium reproduction path?
Gametocytes fertilize to zygote in mosquito, form oocyst, oocyst divides to form sporozoites
Sporozoites passed to humans, form merzoites in liver, infect RBC’s and make more merozoites, some become male/female gametes
What are the two stages of asexual reproduction of malaria in humans? How long do they last?
Exo-erythrocytic (outside of RBC’s, in liver, 1-2 weeks)
Erythrocytic (in RBC’s, 24-72 hours)
Which plasmodium species attack younger RBC’s? Which attack older?
Younger RBC’s attacked by P. ovale and P vivax
Older RBC’s attacked by P. malriae
P. falciparum attacks all RBC’s
What is the periodicity of plasmodium species (seeing fever, chills, sweating)?
P. vivax and P. ovale = 48 hrs
P. malariae = 72 hrs
P. falciparum = 36-48 hrs
What is the RBC morphology for P. vivax?
Enlarged young RBC’s
Trophozoite inside looks ameboid, vacuoles, golden-brown
What is the RBC morphology for P. ovale?
Enlarged fimbriated (spiky) RBC's, infects Duffy neg pts Trophozoite inside looks compact, round, golden-brown
What is the RBC morphology for P. malariae?
Normal, older RBC’s
Trophozoite inside looks like band form accross cell, dark-brown
What is the RBC morphology for P. falciparum?
Normal, RBC’s of all ages
Trophozoite inside looks small, delicate, ring forms, dark pigment
What is reproduction cycle of Babesia?
Sexual reproduction occurs in tick, sporozoites are infective, passed to humans by tick bite
Asexual reproduction in rodents/humans, RBC’s infected and destroyed
Sporozoites formed by binary fission
What is Babesia disease like?
Mild, self-limiting in healthy population, can be fatal in immunocompromised, can be passed via blood transfusion
How to diagnose Babesia?
Giemsa-stained blood smear, see tetrads/maltese crosses in RBC’s, no stippling or pigment in RBC’s
Leishmaniasis similarites of all 3
Vector: sandfly
Promastigotes infective
L. donovani
Infects reticuloendothelial cells, anemia, hepato- and splenomegaly, fatal 1-2 yrs
L. tropica
Skin lymphoid tissue infected, ulcers at bite, itching
L. braziliensis
Infects reticuloendothelial cells, ulcers of oral/nasal skin/mucosa, disfiguring, death due to secondary infection
Trypanosomiasis similarities of all 3
Trypomastigotes infective
T. gambiense
Tsetse fly vector
Lymphatic system/CNS infected
Ulcer at bite, englarged lymph nodes, encephalitis, coma/death
Test CSF samples
T. rhodesience
Tsetse fly vector
Lymphatic and CNS infected
Anorexia, fever, chills, confusion, dementia, death within 9-12 months
Test CSF
T. cruzi
Kissing (reduviid) bug vector, passed by feces of bug
Infects many tissues (heart, brain, liver, eye)
Causes Chagas’ disease, may be asymptomatic, may have fever, chills, edema of one eyelid, englarged organs
Most severe in kids under 5
Filariasis
Blood/tissue nemtodes
Microfilariae (larvae) seen under stain as threadlike, sheathed/unsheathed, nuclei inside
Diagnose based on periodicity, location in host, microfilariae morphology
Wuchereria bancrofti
Mosquito vector
Asymptomatic then symptomatic, fever/chills, lymphadenopathy, elephantiasis
Nocturnal periodicity, pointed tail w/o nuclei, sheath at ends
Brugia malayi
Same as W. bancrofti except 2 nuclei in tail tip
Loa loa
Deerfly vector, infects blood and subcutaneous tissues
Calabar swelling (lymph nodes), worm can be seen in eye (extract from eye to treat)
Diurnal periodicity, tail has continuous row of nuclei, sheath at ends
Onchocerca volvulus
Blackfly vector, infects subcutaneous tissue, skin, eye (test skin, not blood)
Allergic reactions, blindness, chronic
No periodicity, continuous row of nuclei in tail, unsheathed
Toxoplasmosis (Toxoplasma gondii)
Domestic cat vector
Passed via cat feces, undercooked meat, transplacental
Test w/ serology for antibodies
Lyme disease (Borrelia burgdorferi)
Tick vector
1st = bull’s eye rash, flu-like
2nd = heart problems, face paralysis, meningitis
3rd = arthritis/joint damage months/yrs later
Test via serology
