MICROPARA (21) - Parasitic Infections

Parasitology

is a branch of microbiology that deals with the scientific study of parasites

Parasitism

is a symbiotic relationship that is of benefit to one party or symbiont (the parasite) and usually detrimental to the other party (the host)

parasites

are organisms that live on or in other living organisms (hosts), at whose expense they gain some advantage

ectoparasites

parasites that live on the outside of the host's body

endoparasites

parasites that live inside the host

definitive host

is the host that harbors the adult or sexual stage of the parasite

intermediate host

the host that harbors the larval or asexual stage

accidental host

us one that can serve as a host, but us not the usual host in the parasite's life cycle

dead-end host

is one which the parasite cannot continue its life cycle

facultative parasite

is an organism that can be parasitic, but does not have to live as a parasite; it is capable of an independent life

Neagleria fowleri

a free-living amoeba that causes primary amebic meningoencephalitis (a type of facultative parasite)

obligate parasite

has no choice but to inhabit a host/s. it is the type of parasite that mostly infect humans

it depends on a host for nourishment, reproduction, habitat, and survival.

unicellular

most protozoa are (unicellular or multicellular)

their mode of locomotion

parasitic protozoa are classified taxonomically by ___

amoeba

move by means of pseudopodia (false feet)

flagellates

move by means of flagella

ciliates

they move by means of cilia

sporozoans

protozoa that do not move

leishmaniasis

usually transmitted via bite of an infected fly

caused by flagellated protozoan in the genus leishmania.

cutaneous and miccutaneous leishmaniasis

a type of leishmaniasis that can cause severe tissue damage and disfigurement

visceral leishmaniasis

a type of leishmaniasis that can cause death

amedic conjunctivitis and ketatoconjunctivitis

it is caused by several species of amoebas in the genus acanthamoeba (facultative parasites) but can lead to loss of vision or enucleation

toxoplasmosis

caused by toxoplasma gondii an intracellular sporozoan that can involve the central nervous system, lungs, muscle, or heart as well as the eyes and is acquired by ingesting cysts or ooacysts

toxoplasmosis

is a leading cause of death from foodborne illness in the united states

amebiasis

it is caused by entamoeba histolytica. fecally contaminated food or water

balantidiasis

it is caused by balantidium coli that is get from food or water contaminated with pig feces

cryptosporidiosis

it is caused by cryptosporidium parvum that infected humans cattles and other domesticated animals

cyclosporiasis

caused by cyclospora or cayetanensis. physically contaminated water and produce is its mode of transmission

giardiasis

it is caused by giardia lambia is transmitted through humans and infected animals

Entamoeba histolytica

it infects the colon with secondary infection of liver.

Infectious patients pass noninfectious trophozoites as well as infectious cysts in stools.

Diagnosis is by the presence of characteristic cysts (containing one to four nucleic) in stools

Therapy: lodoquinol, metronidazole

Cryptosporidium parvum

infects the lower small intestine

organisms are intracellular parasites in epithelial cells of intestinal villi

Diagnosis is by modified acid-fast stain of stool sample

Therapy: Paromomycin (but often not effective)

Gardia Lambia

infection usually results from drinking contaminated water

it infects the duodenum, with incubation time of about 10 days

acute infection shows sudden onset with foul smelling, watery diarrhea

diagnosis is by the presence of cysts or trophozoites in stools

Therapy: Metronidazole

trichomoniasis

it is caused by trichomonas Vaginalis, a flagellate

a sexually transmitted disease of men (asymptomatic )and women (symptomatic)

it has 1/3 cases of vaginitis in U.S

usually diagnosed by observation of motile trophozoites in a saline wet mount of vaginal discharge material

Trichomonas vaginalis

trophozoites that is 7-23 μm long by 5-15 μm wide

they are constantly in motion, as a result of the flagella and an undulating membrane

Plasmodium falciparum

have a "signet ring" appearance

Primary Amebic Meningoencephalitis

Caused by Naegleria fowleri, an ameboflagellate

Acanthamoeba and Balamuthia spp. can cause

similar conditions

Persons often become infected by swimming

and/or diving in ameba-contaminated water (e.g.,

"the old swimming hole")

After the amebas colonize nasal tissues, they

invade the brain and meninges by traveling along

the olfactory nerves; often fatal

Helminths

means parasitic worm

are multicellular, eucaryotic organisms;

2 major divisions: (1) round worms or nematodes,

and (2)flatworms or Platyhelminthes. The flat worms

are further

divided into tapeworms(cestodes) and flukes

(trematodes).

primarily acquired by ingesting the larval stage; in some cases, larvae enter by penetration of the skin.

egg, larva,

and the adult worm

The helminth life cycle has 3 stages: which are .

Ascariasis

Helminth infection caused by Ascaris lumbricoides (N)

Hookworm infection

Helminth infection caused by Ancylostoma duodenaleor

Necator americanus(N)

Pinworm

Helminth infection caused by Enterobius vermicularis (N)

Whipworm

Helminth infection caused by Trichuris trichiura (N)

Strongyloidiasis

Helminth infection caused by Strongyloides stercoralis (N)

Beeftapeworm

Helminth infection caused by Taenia saginata(C)

Dog tapeworm

Helminth infection caused by Dipylidium caninum(C)

Dwarf tapeworm

Helminth infection caused by Hymenolepis nana (C)

Fish tapeworm

Helminth infection caused by Diphyllobothriumlatum(C)

Porktapeworm

Helminth infection caused by Taenia solium (C)

Rat tapeworm

Helminth infection caused by Hymenolepis diminuta(C)

Fasciolopsiasis

Helminth infection caused by Fasciolopsis buski (T)

Fascioliasis

Helminth infection caused by Fasciolahepatica (T)

Clonorchiasis

Helminth infection caused by Clonorchis sinensis(T)

Insects (e.g., lice, fleas, mosquitoes)

Arachnids (e.g., mites and ticks)

Crustaceans (e.g., crabs, crayfish, and certain

Cyclops species)

3 classes of arthropods studied in Parasitology

courses are

Arthropods

serve as mechanical or biologic vectors

in the transmission of certain infectious diseases.

Mechanical vectors

pick up a parasite at point A

and drop it off at point B.

Biological vectors

harbor the parasite in their

body, where the parasite matures and/or

multiplies.

Dermacentor

andersoni

wood tick,

one of the tick vectors

of Rocky Mountain

spotted fever

Xenopsylla cheopis

oriental rat

flea, vector of plague

and endemic typhus

Pediculus humanus

human body louse; a

vector of epidemic

typhus

Phthiruspubis

the

pubic or crab louse