PARASITOLOGY LEC EXAM 1 REVIEWER

Clinical parasitology

deals with the parasites of the man and their medical significance

Parasitology

area of biology concerned with the phenomenon of dependence of one living organism on another

Host

larger organism which provides physical protection and noursihment

Definitive/ Final Host

in which parasites attain sexual maturity (man)

Immediate Host

Harbors the sexual or larval stage of the parasite

Paratenic/ Transport Host

No development occurs but the parasite remains alive and infective

Reservoir Host

allow parasite’s life cycle to continue and become additional sources of human infection

Vector

transmits parasites to humans or animals

Zoonosis

parasites found in animals are transmitted to human (usually through consumption)

Obligate parasites

Cannot exist without a host

Free living stage

Live outside the host within a protective eggshel or cyst

Facultative parasites

* live either a parasite or a free-living existence


* type of parasites that is flexible

Infection

produced by endoparasites found inside the body

Infestation

produced by ectoparasites outside the body

Commensalism

only one parter benefits from the association but the host is neither helped nor harmed

Mutualism

Relationship is beneficial both to the parasite and the host

Parasitism

one partner benefits at the enzyme of the other

parasitism

most type of relationship the parasites adopt to

Pseudopodia/ Pseudopods

temporary extensions of the cells/ plasma membrane and used for locomotion and feeding and movement is like protoplasmic streaming

pseudopods

utilizes iron from RBC

flagella

slender whip-like structure

cilia

Tiny, hair-like structure composed of kinetids

kinetids

functional unit of cilia

Binary fission/ longitudinal binary fission

parasites produces asexually via

2 daughter cells

how many daugher cells will Binary fission/ longitudinal binary fission give off?

multiple fission

nucleus of the parent divides into many daughter cells by?

sexual reproduction

involves the participation of 2 whole cells

Gametogony

meiosis, sexual reproduction by union of 2 whole cells

gametes

daughter cells is also called as

mouth

most common point of entry

fomites

exposure from inanimate objects

traumatic damage

when the parasite puctures the skin producing wounds, that’s when trauma happens

Lytic necrosis

enzymes are involved, enzymes are released by the parasites and digest possible food that is available in the environment

surgical intervention

method of treatment for macroorganisms

Cellular proliferation and Infiltration

there is an increase in the RBCs/ WBCs at the site of parasitic infection

Trypanosoma cruzi

etiologic agent of Chagas disease or American trypanosomiasis

Stercoraria

group of Trypanosoma cruzi

myocytes and reticuloendothelial sytsem

heavily infected cell of Trypanosoma cruzi

reduviid bug

what is the vector of Trypanosoma cruzi?

amastigotes

diagnostic stage of Trypanosoma cruzi

trypomastigotes

infective stage of Trypanosoma cruzi

bloodstream

in humans trypomastigotes are found in

tissue cells

in humans amastigotes is found in

midgut

in vector amastigote, epimastigote and promastigote is found in

hindgut

in vector trypomastigote is found in

amastigote

* round/ovoid shape
* 1.5-4 micrometer
* found in small groups of cysts like collections in tissues

trypomastigote

* 15-20 micrometer
* pointed posterior end
* has an undulating membrane with 2-3 undulations

trypomastigote

* has a single thread-like flagellum
* C-shaped in stained specimens

Trypanosoma cruzi

associated with megasyndrome

acute stage

focal or difuse inflammation mainly affecting myocardium

Chagomas

furuncle like lesions associated with induration, central edema, regional lymphadenopathy also represents as a site of entry for parasite

Romana’s sign

eyelid swelling

Latent/indeterminate phase

this stage is usually asymptomatic but still capable of transmitting the disease through vectors, blood transfusion and organ transplant

1/3

about ____ developes to chronic stage

chronic stage

stage that is multifactorial which means that it is dependent on the reaction between the parasite and the host

heart

primary affected organ in chronic stage

megasyndrome

fibrotic reactions leads to ____

direct visualization of the parasites in thick and thin blood smears using Giemsa stain

definitive diagnosis of acute stage

2 months

trypomastigotes can only be detected in the first ____ of acute disease

2 techniques

for chronic stage, it recommends at least ____ to show a postive result

Nifurtimox and Benznidazole

used to treat Trypanosoma cruzi

10 million

Trypanosoma cruzi infected more than ___ worldwide

Latin America

most cases of Trypanosoma cruzi is in

Central and South America

endemic areas are ___

third

In 2003, it ranked as ___ as the leading cause of parasitic infection worldwide

Trypanosoma brucei gambiense, Trypanosoma brucei rhodesiense, Trypanosoma brucei brucei

What are the 3 Trypanosoma brucei or also known as the Trypanosoma complex

Human African Trypanosomiasis

Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense causes

African sleeping sickness

a highly fatal disease

Trypanosoma brucei brucei

it affects wild and domestic animals

east Africa

Trypanosoma brucei rhodesiense is endemic in ____

Western and Eastern region of Sub-Saharan Africa

Trypanosoma brucei gambiense is endemic in _____

Trypanosoma brucei gambiense

primarily affects human but utilizes dogs, pigs and sheep as a reservoir hosts

Trypanosoma brucei rhodesiense

primarily a zoonosis of cattle and wild animals

Trypanosoma brucei rhodesiense

humans are accidental hosts

Trypanosoma brucei gambiense

chronic type of sleeping sickness

Trypanosoma brucei rhodesiense

more rapid and acute fatal form of sleeping sickness

Trypanosoma brucei gambiense

Causes 95% of cases of Human African Trypanosomiasis

Trypanosoma brucei rhodesiense

Causes 5% of cases of Human African Trypanosomiasis

epimastigote and trypomastigote

the only 2 stages of Trypanosoma brucei complex

chancre

initial lesion, painful, local, pruritic, erythematous located at bite site progressing into a central eschar, resolving after 2-3 weeks

Trypanosoma brucei gambiense

chancre is more common in

hemolymphatic

early phase is also known as

1-6 months

early phase lasts for how many months

Winterbottom’s sign

for Trypanosoma brucei gambiense- posterior cervical lymph nodes are enlarged, nontender and rubbery

Late phase

This phase involces the CNS

meningoencephalitic

late phase is also known as

3-10 months

Trypanosoma brucei gambiensein late phase occur ____ after initial infection

after few weeks

Trypanosoma brucei rhodesiense manifests ___

Kerandel’s sign

deep, delayed hyperesthesia

Antigenic variation

ability of trypanosomes to continuously change its surface coat so that the host’s antibodies can’t recognize the parasite in subsequent waves of parasitemia

Early phase/ hemolymphatic

diagnosis is usually done in what phase?

Giemsa stain

used for thick and thin blood film

Buffy coat concentration

recommended to detect parasites in low numbers

Card agglutination test (CATT)

* detect circulating antigens in persons infected with Trypanosoma brucei complex
* rapid and highly specific method for screening
* available commercially

Intravenous Suramin Sodium

used to treat Trypanosoma brucei gambiense/ rhodesiense in early phase

Intramuscular pentamidine

used to treat Trypanosoma brucei rhodesiense in early phase

Intravenous melarsoprol

drug of choice for both type of sleeping sickness during the late phase

Nitrofurazone

second line of drug for late phase

Eflornithine

* may also be used during the early phase
* less toxic than melarsoprol
* only effective against Trypanosoma brucei gambiense

Trypanosoma brucei rhodesiense

is an occupational hazard for persons working in game reserves and game parks