Parasitology exam 1

phoresis

involves 2 organisms traveling together WITHOUT any biological or physiological interdependence

mutualism

both organisms benefit, often with a necessary physiological reliance; typically obligatory

commensalism

1 organism benefits while the other is unaffected, such as Entamoeba gingivalis in the human oral cavity

parasitism

1 organism either harms or lives at the expense of it host

definitive host

host where the parasite achieves sexual maturity

intermediate host

necessary for the parasite’s developmental stages bit without sexual maturation

paratenic (transport) host

doesn’t support parasite development but can help bridge ecological gaps between hosts

reservoir (amiplifying) host

can carry pathogen indefinitely without harm

dead-end or incidental host

don’t develop high parasite levels; unable to transmit the pathogen further

hyperparasitism

parasite hosting for another parasite

vector

organism, often an anthropod, transmitting a pathogen from reservoir to host (like sand fly or tsetse fly)

aberrant host

atypical host for the parasite it carries

host specificity

some parasites are specific to one host, while others can develop in multiple hosts

ECTOparasite

lives on the host’s surface (ex. tick-Ixodes scapularis)

ENDOparasite

parasite resides inside the host (ex. trypanosoma bruci or plasmodium falciparum)

Facultative parasite

does’t rely on host for survival; incidental

Obligate parasite

needs host for survival and life cycle completion

mechanical damage

causes physical harm or obstruction in tissues

physiologic damage

affects metabolism; consumes host’s nutrients

direct life cycle

parasite completes life cycle within a SINGLE host

indirect life cycle

parasite needs multiple host species for completion; typically involing 2-3 hosts: definitive, intermediate, and paratenic

prevalence

proportion of a population infected as a specific time

incidence

rate of new infections in a population

morbidity

refers to illness or disease state

co-morbidities

presence of simultaneous illnesses

mortality

incidence of death due to a disease

sexual repreduction

mixes genetic material form the parents to produce offspring; enhance the host population’s resistance to disease

sexual selection

parasite influence the host’s choice of mates, chooses “healthy” mates or “unhealthy” ones

Asexual parasite reproduction (4 types)

• Polyembryo: development of many offspring from a single zygote

• internal budding: new individual grows from the somatic tissue of parent

• Schizogony (multiple fission, merogony): produces many daughter cells; nucleus divides many times before cytokinesis occurs

• binary fission: mitotic division of 1 cell into 2 cells

Sexual parasite reproduction (2 types)

• monoecious: everything needed for reproduction in 1 organism; self-fertilization; no need to find mate

• dioecious: 2 genders involved

Trypanosoma brucei (aka african sleeping disease) (2 kinds)

• Trypanosoma brucei rhodesiense

• Trypanosoma brucei gambiense

Life cycle in Tsetse fly: tsetse fly bite (ingest bloodstream trypomastigote), trypomastigote become procylic trypomastigote & go in midgut, procyclic trypomastigote leave midgut & become epimastigote, epimastigote multiply in salivary gland & become metacylic trypomastigote

Trypanosoma brucei rhondesiense

Vector: Tsetse fly

Infective stage: trypomastigote

Progression: days-weeks, Acute, rapid onset, most likely to evove to death, coma

sign: tsetse fly bite

Location: East africa cattle-rasiing countries

Reservoir host: wild game

Trypanosoma brucei gambiense

vector: tseste fly

infective stage: trypomastigote

progression: months-years, chronic, slow,

sign for it: Winterbottoms sign (swollen lymph nodes), tsetse fly bite

Location: tropical West & central africa, homes/work near streams

Reservoir host: none

trypanosoma brucei life cycle in human

Life cycle in human: tsetse fly bite (inject metacylic trypomastigote), trypomastigote go into bloodstream, either acute T.b rhodensiense (trypomastigote in blood & lymph) or chronic T.b gambiense (trypomastigote in CNS)

trypanosoma brucei life cycle in tsetse fly

Life cycle in Tsetse fly: tsetse fly bite (ingest bloodstream trypomastigote), trypomastigote become procylic trypomastigote & go in midgut, procyclic trypomastigote leave midgut & become epimastigote, epimastigote multiply in salivary gland & become metacylic trypomastigote

which life cycle stage of Leishmania would you find intracellular

amastigote

which type of leishmania is cause by L. donovani?

visceral

Leishmania species

Vector: sand fly (female)

definitive host: mammals

Obligate intracellular—-becomes amastigote

Location: worldwide, mostly found in rural areas, poor housing

types of disease from Leishmania

1. Cutaneous Leshmaniasis

2. Visceral Leishmaniasis

3. Mucocutaneous Leishmaniasis

Cutaneous Leishmanasis species (skin infection)

1. L. tropica

2. L. major

3. L. mexicana

L. tropica & L. major

Vector: female sandfly

Infective stage: amastigote found in phagocytic cells & lymphoid cells

Progressions: days-weeks-months, bite—> ulcers/lesions

Locations: Africa, middle east, Asia, India

L. tropica ulcers

dry, takes months, contains MANY amastigotes

L. major ulcers

wet, sticky, FEW amastigotes

L. mexicana

vector: female sandfly

Infective stage: amastigote—procyclic

Location: Central & South America, North America

Definitive Host: human

RH: donkeys, sloths, rodents

Sign: ulcers, ear ulcers

Cutaneous L. info

Diagnosis: presence of amstigotes

Treatment: limit vector, self-limiting

Mucocutaneous Leishmaniasis (mucus place infection such as nose)

L. braziliensis

L. braziliensis

Vector: sandfly

DH: Humans

RH sloths, anteaters

Location Central & South America

Diagnosis: presence of amstigotes in tissues

Treatment: NOT SELF LIMITING, Amphotericin B

Control: limit vector, hard to control with RH

Visceral Leishmansis (organ infection)

L. donovani

L. donovani

DH: humans

RH: dogs most important

Vector: sandfly

Location: Asia, Africa, South & Central America

Infective stage: amastigotes

Diagnosis: presence of amstigotes in organs—likes spleen & liver

Progression: varies, could be days-year, or months

Slower onset: fever, waste, enlarged spleen & liver, death in 2-3 years

Rapid onset: fever, chills, vomiting, bleeding of mucus membranes, diarrhea, death in 6-12 months

Bleeding in organs, decrease in red blood cells

which trichomonad has 3 flagella

tritrichomonas

which trichomonad has 4 flagella

trichomonas

which trichomonad has 5 flagella

pentatrichomonas

what trichomonad causes UTI symptoms

Trichomons vaginalis

most common flagellate of human GI tract

Giardia

Giardia

Distribution: widespread

Route of infection: ingestion of cysts, contaminated water, Fomites (grab diaper w fecal matter)

Zoonosis: “bever fever”

Direct life style

Location: worldwide, childeren most infected

Causes you to go to bathroom a whole lot, diarrhea, skinny, clay colored diarrhea

Diagnosis: presences of trophozoite or cysts in feces

Treatment: metronidazole, all household members treated

Giardia intestinalis — cysts

diagnostic stage: cysts found in feces (each cyst produces 2 trophozoites)

Giardia intestinalis—-trophozoites

diagnostic stage: found in feces

trophozoite sucks onto small intestine—> cysts moves back up toward colon

Giardia direct Life cycle

ingest cyst, cyst break down into 2 trophozoite, trophozoite multiples binary fission, 4 separate trophozoite, go back into cyst

Trophozoites

pryriform—pear shape

4 pairs of flagella (8 flagella total)

2 median bodies

adhesive ventral sucking disk

2 nuclei

Cysts

4 nuclei

4 media bodies

6 flagella

Trichomoanas vaginalis

Transmitted sexually—effects reproductive tract of male & female (vagina, urethra, prostate, seminal vesicles)

DH: humans

4 anterior flagella

Direct Life cycle

Extracellular—no cyst stage

DIagnosis: presence of parasite motility in urine

T. vagininalis in females

UTI symptoms

frothy discharge

painful urination

premature babies

low birthrate

T. vaginalis in males

inflammation of prostate, urethra

clear or green, thin discharge

painful urination

enhance HIV transmission

Trichomonas feotus (in cattle mostly)

DH: cattle, cats

sexually transmitted—no cyst stage

pregnancy triggers systemic infection

trophozoite invade uterus

3 anterior flagella

T. foetus in Bulls (males)

cannot be used for breeding

diagnosis: presence of parasites

only treatment for very valuable animals

affected bulls must be culled (killed)

T. foetus in cows (females)

abortion

recover spontaneously

may develop sterility

diagnosis: presence of parasites

no treatment: usually self-limiting