Medical parasitology lab Medical parasitology lab

Infect human and most mammals. The infective stage is oocyst containing

sporozoites measuring 4-6µ in diameter. The diagnostics stage is oocyst

containing 4 sporozoites. Diagnosis:

Detecting oocyst in stool. Acid-fast stain

Isosporiasis is a human intestinal disease caused by the parasite Isospora belli.

The coccidian parasite Isospora belli infects the epithelial cells of the small intestine, and is the least common of the three intestinal coccidia that infect humans.

Infection causes acute, non-bloody diarrhea with crampy abdominal pain, which can last for weeks and result in malabsorption and weight loss. In immunodepressed patients, and in infants and children, the diarrhea can be severe. Eosinophilia may be present.

Diagnosis: Acid- fast stain

Cryptosporidium parvum_ wet Cryptosporidium parvum_ wet mountmount

*Oocysts in clinical specimens may be difficult to identify with out special staining.

*Modified acid-fast (partial acid-fast) stains are recommended for identifying these organisms.

*This test detects coccidian parasites (Cryptosporidium, Cyclospora, or Isospora belli) in stool. It is used to evaluate chronic diarrhea.

Isospora belli oocystIsospora belli oocystCryptosporidium parvum oocystCryptosporidium parvum oocyst

*The oocysts absorb the red from the carbol-fuchsin stain and may appear in a range of colors from pink to dark purple with bright red being typically seen.

*The background material typically stains blue or light red.

*Specimen Collection

Concentrated sediment of fresh or formalin preserved stool may be used. Other types of clinical specimens such as bile , duodenal fluid, pulmonary fluid (induced sputum, bronchial washings, biopsy specimens may also be used to stain for organisms.

1 2 3

4 5

1- carbol-fuchsin for 3-5mint

2-rinse by tap water3 - add acid alcohol as

decolorizer for 1mints4 -rinse by tapewater

5 - add methylene blue ascounter stain for 1 mint

Rinse by tapewater then examine under oilimmersion.

1-carbol-fuchsin for 3-5 mint

2-rinse by tap water3 -add acid alcohol as

decolorizer for 1mints4 -rinse by tapewater

5 -add methylene blue as counter stain for 1 mintRinse by tapewater then examine under oil immersion.

*The  iron hematoxylin stain reveals excellent morphology of the intestinal protozoa.

*Iron hematoxylin was the stain used for most of the original morphological descriptions of intestinal protozoa found in humans .

*Under oil immersion power (1,000),one can examine the diagnostic features used to identify the protozoan parasite.

Appearance of select protozoan structures and background material on the iron hematoxylin stain

Protozoa cytoplasm Blue to purple

Protozoa nuclear material

Dark blue to dark purple

Debris and background material

Light blue sometimes with pink tint

Place approximately 50 ml of deionized water in separate coplin jar.

•General characters General characters 1.Non segmented2.Sex are separate

Male is smaller than female and its posterior end is curved ventrally.

Female are either •Larviparous or viviparous: giving birth to larvae•Oviparous: laying egg• Oviviviparous: laying eggs which contain larvae and which hatch

out immediatly

•General characters General characters 1.Non segmented2.Sex are separate

Male is smaller than female and its posterior end is curved ventrally.

Female are either •Larviparous or viviparous: giving birth to larvae•Oviparous: laying egg• Oviviviparous: laying eggs which contain larvae and which hatch

out immediatly

Trichinella spiralisTrichinella spiralis

Adult inhabit the small intestine of the rats, pigs and human. Both males and females lie freely in the lumen of the intestine of pigs, rats and human.

Fertilized female only penetrate the mucosa where the larviposit, they do not lay eggs.

Disease trichinosis, trichiniasis or trichinelliasis

infective stage Larvae is live encysted in the flesh of the host ,

diagnostic stage. Larvae

Route of infection

eating undercooked pork containing

infective encysted larvae.

dead end host. Human

Diagnosis: 1. Finding larvae in the blood during migration or in muscle after encystation.

2. Immunological tests.3. X- ray to detect the calcified larvae in

muscle.

Trichinella spiralisTrichinella spiralis

Eggs

Adults

• Young and mature worms are present in small intestine (at terminal ileum till fertilization).

• Young and mature worms are present in small intestine (at terminal ileum till fertilization).

Egg Morphology :

20-50u, transparent with double walled shell.•Oval, It may show one side convex and the other flat.•Shell: double layered, thick, colorless. •Embryo stage of development varies may be unembryonated, embryonated, mature.

• Microscopically examined the slide under low power. Reduced light is recommeneded as the eggs will appeear colorless, making them difficult to detect under high light intensity .

• Microscopically examined the slide under low power. Reduced light is recommeneded as the eggs will appeear colorless, making them difficult to detect under high light intensity .

*These cells are readily differentiated from parasitic forms because they lack internal structures.

The male is shorter than female (2-5 mm) the tail is curved strongly to ventral side, and has a single spicule.

The tail of female pointed resembles pinhead

The tail of female pointed resembles pinhead

Alternative names human pin worm and seat worm

Disease oxyurdiasis.

Infective stage Embryonated Eggs

Definitive host human

Diagnosis:When found in feces, the eggs are typically unembryonated as seen in this wet preparation. The typical embryonated (infective) eggs are usually seen in the cellulose tape preparation the most reliable means for detecting the

parasite .

1. Egg in stool is rarely detected but adults present after purgative.

2. Egg can be detected at perianal area as follow:

1. N.I.H method (National Institute of Health), its based on swabbing the perianal area with a cellophane paper.

2. The adhesive cellulose tape (scotch tape), better result.

3. The Vaseline cloth wiping, the collected

ova examined.

1. Adhesive tape

2. Use gloves !(pinworm eggs are infectious!)

3. Prepare the tape then Take sample on peri-anal skin in the morning

4. Stick tape on microscope slide

5. Place a drop of Xylene on the edge of the tape to remove airbubbles

• Adult inhabit the large intestine in the caecum of man.

• The adult male smaller than female, male 3.4-4.5 cm, female 4-5 cm.

• Its commonly called whip worm because of the shape of this worm (anterior thin and posterior thick).

Trichuris trichiura eggs have distinct shape. (oviparous)

Shell:smooth,yellow brown color due to bite contact.

Hyaline plug at each pole. Diagnosis:

Stool examination to detect eggs.

Trichuris trichiura eggs have distinct shape. (oviparous)

Shell:smooth,yellow brown color due to bite contact.

Hyaline plug at each pole. Diagnosis:

Stool examination to detect eggs.