intestinal parasite

8/10/2019 intestinal parasite

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Departeman ParasitologyFK USU

INTESTINAL PARASITES

INFESTASION


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Specific Learning Objective:

Intestinal Nematodes;

Describing the life cycle of Enterobius vermicularis

Explaining the pathogenesis and patophysiology of

enterobiasis

Explaining the parasitologic examination and

prevention of enterobiasis


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Intestinal Cestodes;

Describing the life cycle of Taenia saginata, Taenia

solium, and Hymenolepis nana

Explaining and comparing the pathogenesis and

pathophysiology taeniasis saginata, taeniasissolium, and hymenolepiasis nana.

Explaining the parasitologic examinations and

preventions of the infestations of intestinal cestodes


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Intestinal Protozoas; Describing the mechanical vectors of amoebiasis

Describing the life cycle of Entamoeba histolytica,

Giardia lamblia, and Balantidium coli.

Explaining the pathogenesis and pathophysiology

of amoebiasis, giardiasis, and balantidiasis.

Explaining the parasitologic examinations and

preventions of amoebiasis, giardiasis, and

balantidiasis


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Enterobiasis

Etiology:Enterobius vermicularis

(Oxyuris vermicularis/ pin worm/ thread worm/seatworm).

Habitat:Large intestine (caecum and appendix).Sometimes in ascending colon and ileum.


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Route of infection:

1. Ingestion infectious egg

2. Direct transfer/Autoinfection3. Retroinfection4. Inhalation : contaminated and airbone

transmission


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Life cycle


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Pathofisiology

The adults are mainly located in the caecalregion and female deposits her eggs on the

anus and perianal skin usually at night.

The sticky, gelatinous substance in which theova are deposited and the movements of the

female worm cause perianal pruritus.


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Diagnosis

1. Anal swab ( N.I.H swab )

2. Suspected in children with perianal itching and

scratching, sleeplessness and restlessness..3. Typical egg shape in feces, nail clipings, bedlinen


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Prevention

Treat all family members.

Personal grooming clean and short fingernails.

Personal hygiene wash hands before eating andafter defecation.

Frequent washing of bedlines and clothes with soapand water.


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Taeniasis

Ethiology: T. saginata and T solium

Habitat : small intestine, yeyunum


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Taenia saginata


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Mode of transmision

Ingestion of raw or insufficiently cooked

meat harboring cysticercuscellulosae/cysticercus bovis.


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Life cycle


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Pathofisiology

Ingestion of egg : cysticercosis

Ingestion of larvae : taeniasis

Taeniasis solium : autoinfection

Clinical manifestation : heavy

On human : taeniasis solium


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Diagnosis

QDP (Questionaire DemonstrationProglottid)

Motile proglottid in feces Anal swab


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Prevention

Personal hygiene

Avoid consuming raw or unproperly cooked

meat Treatment of infected person


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Hymeno lepis sp .

Hymenolepis nana

Hymeno lepis dim inuta

Called dwarf tapeworms orRat tapeworms

Distributed in warm climates.


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Hymeno lepis nana

Cysticercoid has hooks in the anterior part Maturation in 2-4 weeks

Length depends on parasitemia, mostly only 1-3 cm

Scolex has 4 suckers and a short rostellum with 20-30retractable hooks

Mature proglottid has three testes and a uterus

Gravid proglottid is occupied by the uterus filled w/100-200 eggs

The eggs are spherical with diameter 60-80 mm

The nodes and filamentous substance are not usuallyseen

Contains hexacanth embryo


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Hymeno lepis nana

Life cycle


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Nature of the disease Hymenolepis is generally found in the feces of rats

which is consumed by its secondary hosts: beetles.

The worms mature into a life form referred to as a

"cysticercoid" in the insect; in H. nana, the insect is

always a beetle. Humans and other animals become infected when

they intentionally or unintentionally eat material

contaminated by insects.

In an infected person, it is possible for the worm'sentire life-cycle to be completed in the bowel, so

infection can persist for years if left untreated.


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Nature of the disease

Hymenolepis nana infections are much morecommon than Hymenolepis diminuta infections in

humans because, in addition to being spread by

insects, the disease can be spread directly from

person to person by eggs in feces. When this happens, H. nana oncosphere larvae

encyst in the intestinal wall and develop into

cysticercoids and then adults.


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Preventive action

Good hygiene

Public health and sanitation programs

Elimination of rats help prevent the spread of

hymenolepiasis.


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Amoebiasis Coli

Caused by Entamoeba histolytica Humans are infected by ingesting cysts, most

often via food or water contaminated withhuman fecal material

Trophozoites live in the host large intestine

Cysts survive outside the host in water andsoils and on foods

E. histolyticais potentially the mostpathogenic protozoa in human intestine

Clinical incubation period 1-14 wks


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Life Cycle of

E. Histolytica

Relatively simpleand directbeingtransmittedfrom one host tothe next viaafree-livingresistant stage -the cyst


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Amoebiasis ColiNature of Disease

Infection may be accompanied by:1. No symptoms

2. Vague gastrointestinal distress

3. Dysentery (w/ blood and mucus) Complications include:

1. Ulcerative and abscess pain

2. Intestinal blockage (rare)

3. Trophozoites infect other organs (mostlyliver)amoebic liver abscess


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Amoebiasis ColiPathology

Intestinal invasion: ulcerous flask shapedlesions, may lead to perforation

Extra intestinal amoebiasis: various organs,

mostly liver (typical abscess) Colon ulceration can spread to other sites by

such ways:1. Percontinuitatum(to secondary sites)

2. Hematogen(to distant organs)


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Amoebiasis ColiDiagnosis

Based on clinical symptoms Beware of carrier person! Stool examination: normal saline, lugol,

trichrom, and hematoxiline stains, orconcentration method Serologis test, especially for extra

intestinal amoebiasis patients

The parasite must be distinguished fromother parasitic (but non-pathogenic)protozoa


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Amoebiasis ColiPreventive Treatment

Treat the patients and carriers

Health education

Proper meal preparation and storage The use of proper toilets, drinking water

facilities, and garbage cans


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Giardiasis Intestinalis

Caused by Giardia lamblia, a flagellate Regarded as the most common flagellate in

the human digestive tract and is highlycontagious

Found throughout the world Travelers diarrhea Trophozoites live in the small intestine of the

host


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Life Cycle of

G. lamblia

Cyst are takenin orally,usually viacontaminateddrinking water

Thetrophozoitesmay divide bybinary fission

Trophozoitescan encyst andpass out withthe feces


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Giardiasis IntestinalisNature of Disease

G. lambliadoes not invade the tissues of thesmall intestine

Patients harboring this protozoan can be

asymptomatic carriers Or exhibit all or some of the following

symptoms: diarrhea, dehydration, abdominalpain and weight loss


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Giardiasis IntestinalisNature of Disease

Type of diarrhea:1. no blood loss

2. fatty consistency as a result of fatmalabsorption

3. occurs in heavy infections where attachedtrophozoites can cover much of theintestinal epithelial surface

The symptoms may be associated w/ thestrain of variable virulence and hostimmune response


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Giardiasis IntestinalisDiagnosis

Stool examination: visualizing both troph.or cyst in stained/unstained preparation

Concentrated method: floatation orsedimentation

ELISA


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Giardiasis IntestinalisPreventive Treatment

Similar to those w/ other intestinal protozoa:

The most important is to avoid using

contaminated drinking water or food Treat the patients and carrier persons

properly

Health education


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Balantidiasis Coli

Caused by Balantidium coli, a ciliate protozoa

The parasite live in large intestine

Occurs in humans, swine, rodents, and in many

other mammals, and can be transmitted readilyamong these species


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Life Cycle of B. coli

Direct lifecycle Balantidiasis

is oftenoccurs in

swine, andrare in human Swine is

considered asa potentialreservoirhost forhuman


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Balantidiasis ColiNature of Disease

It can give various features, fromasymptomatic, mild to severe, according tothe virulence o/t parasite

Mild illness include gastrointestinaldiscomfort or mild diarrhea Trophozoites attack intestinal epithelial

tissue, causing flask-shaped ulcers (similar

to amebic ulcers) and secondary bacterialinfection Ectopic infection can also occur


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Balantidiasis ColiDiagnosis

Clinical features

Stool examination

Biopsy occasionally needed in ulcer cases orectopic infections


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Balantidiasis ColiTreatment

Drug of choice: metronidazole

Preventive treatment is far more importantto prevent the disease

intestinal parasite

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