Clinical parasitology

Parasitology

-produce disease pattern in man

-special field in Biology and it is the study of

parasite and parasitism

Nonpathogenic

-doesn’t produce disease pattern in man

Parasites

Example: Entamoeba-coli

-any organism that lives in or on the body of

another organism

BETWEEN THEM

Symbiotic relationships

Obligatory

Commensalism

-2 organisms benefit without harming each

are completely dependent upon the host

other

Ex: Ascaris lumbricoides

Example: Entamoeba hystolitica

Facultative

Mutualism

-2 organisms of different species benefit from

Parasites according to MODE OF RELATIONSHIP

-Parasite that takes up permanent residence and

-Parasite that exists in the free-living state and

become parasitic when the need arises.

each other

Ex: Strongyloides stercoralis (strong independent:

Example: anemone and clownfish, termites and

undergoes partenogenity)

flagellates

Intermittent Parasites

Parasitism

-only visit the host during feeding time

-One organism lives in or on another organism

Ex:Arthropods (mosquito)

for survival

Parasites according to MODE OF TRANSFER

Parasites according to HABITAT

Soil-transmitted

Ectoparasite

-most common MOT

-parasite living outside of the body

-developed further in the soil before they

-infestation

become infective

Endoparasite

Ex: HATS (Hookworm, Ascaris lumbricoides,

-parasite living inside of the body

Trichuris trichiura, Strongyloides stercoralis)

-infection

Ascaris lumbricoides: egg in the stomach and

releases in feces to become infectious in the

SOIL (emb

Kinds of vector

Snail Transmitted

-developed further in the body of a snail

Biologic vector

Ex: Flukes or trematodes

Water Transmitted (Protozoans)

Ex: mosquito

Ex: Cyst of amoeba of flagellates

Food Transmitted

-developed in the flesh of animals that man

Ex: fly, cockroach

utilised as a source of food

Ex:

Kinds of host

Taenia saginata: beef

Tenia solium: pork

Toxoplama gondii: cat

Trichinella spiralis: bears, deers, hunted

the parasite

-one that transmit the arasite only when it

has completed its development within the host

Mechanical/Phonetic vector

-transport parasite from one host to another

Definitive host (mature parasite/sexual stage)

-harbors the adult or the sexual stages of

animals

Intermediate host

Contact Trnsmitted

-harbors the arousal/larval stages of the

-does not develop any further because they

parasite

happen to be readily infective

Ex:

Reservoir host

Trichonomas vaginalis: pingpong disease (2-way

-host that allows the parasite life cycle to

treatment)

continue and becomes an additional source for

Enterobius vermicularis: collected through

human infection

scotch tape method in the first MORNING)

Ex: Naegleria fowleri (dirty water)

>female worm lays egg in the anus at night

Paratenic

Arthropds/Vector Transmitted

-host wherein the parasite does not develop

-developed in the body of arthropods before

to later stages

they become infectious

Ex: Ascaris lumbricoides>cockroach (it doesn’t

Ex: Malarial parasite, Filarial worms,

need the cockroach to develop or mature, it

Trypanosoma, Leishmania spp.

needs the man)

Soil: embryonated and carried by cockroach

Malaria definitive host: mosquito (Anopheles)

because it forms in the mosquito

Portal of entry

Sporizoides: Malarial infected mosquito to man

Gametocyte: Non infected mosquito to infected

man

A. Oral

>Ingestion of infective stage (fecal aura)

Ex: Embryonated eggs of Ascaris in soilp

b. Invade

>Intimate Oral Contact

Pathogenesis

Ex:

Entamoeba gingivalis: gums, poor oral hygiene,

kissing, sharing of utensils

Trichomonas tenax: tenax meaning tenacious

or strong, cannot be removed by routine

practices

Entamoeba hystolitica: penile amoebiasis/oral

sex

B. Skin

>Active Larval Penetration

Ex: Filariform larva of hookworm,

Strongyloides stercoralis, Schistosoma

Hookworm: Soil penetration parasite

Snail: Water penetration parasite

Cercaria: 4th stage, infective stage of

Schistosoma

Metacercaria: 5th stage, infective stage of

trematodes except Schistosoma

>Arthropod vector

Ex: Malarial, Filarial, Worm, Trypanosoma,

Leishmania

>Sexual Intimacy/Intercourse

Ex: Trichomonas vaginalis (urine specimen)

>Transplacental (Trophozoile)

Ex: Toxoplasma gondii

>Airborne

Ex: Enterobius vermicularis, Ascaris

lumbricoides

>Intranasal

Ex: Naegleria fowleri: doesn’t live in

chlorinated water, Acanthamoeba: in solution of

contact lens, Hartmannella

>Trauma of Physical Damage

a. Penetrating the skin

Ex: Necator americanus, Ancylostoma duodenale,

Strongyloides stercoralis

Plasmodium Malariae: infects mature RBC

Plasmodium vivax: infects immature RBC

Plasmodium falciparum: infects all RBC, causes

black water fever

b. Invade

c. Destroyed Pulmonary Capillaries (heart to

lung migrations)

Ex: ASH

Ascaris lumbricoides

Strongyloides stercoralis

Hookworms

d. Destruction by Obstruction

>toxic or Allergic Phenomenon

-Schistosoma (causes swimmers itch)

‘leaves tail in the penetration site, immune

system attacks tail and the body goes to the

target area)

-Giardia lamblia: traveler’s diarrhea

Trichinella spiralis: muscle worm (uses muscle

biopsies)

Urine

Ex: Trichonomas vaginalis

Sputum

-Paragonimas westermanum (causes phlegm)