At te end of lecture stdents should be able to know,
Morphology of giarda lambdia,
Life cycle of giarga lambdia.
Morphology of cryptosporidium.
Life cycle of cryptosporidium.
GIARDIA LAMBLIA GARDIA INTESTINALIS
One of the earliest protozoan flagellate parasite was first
discovered by Leeuwenhoek
in 1681 while examining his own stool.
It was named Giardia after Prof. Giard of Paris lamblia after
Prof. Lambl Prague who gave a detailed description of the
It is the most common intestinal pathogen. Infection may
be asympto- matic or cause diarrhoea
MORPHOLOGY AND LIFE CYCLE
The only protozoan parasite found in duodenum and upper
Exists in the vegetative (trophozoite) and cystic forms.
TROPHOZOITE : When viewed flat, the shape of the
trophozoite is looked like that of a tennis or badminton
It is rouded anteriorly and pointed posteriorly, about 15 um
long, 9 um wide and 4 um thick.
It has been described variously as pyriform, heart shaped
or racket shaped.
Dorsally it is convex and ventrally it has a concave sucking
disc which occupies almost the entire anterior half of the
It is bilaterally symmetrical and possesses two nuclei.
four pairs of flagella and a concave suction disc with which it
attaches to the intestinal wall.
The oval cyst is thick walled with four nuclei and several
internal fibers. Each cyst give rise to two trophozoites
during excystation in the intestinal tract.
PATHOGENESIS AND EPIDEMIOLOGY
Contaminated food & water with cyst transmit the
Excystation occur in duodinum & trophozoite attaches to
the gut wall but does not invade.
Multiply by binary fission and causes inflam of the
duodenal mucosa leading the malabsorption of protein and
Feeding by pinocytosis.
Organism is found worldwide.
Carriers pass cysts for years but about 50% of them are
IgA deficient persons show the development of symptoms.
Not only the disease is endemic but it usually shows the
outbreaks in children day-care centers and among patients
in mental hospital.
CLINICAL FINDINGS :
Nonbloody diahorroea, with nausea, anorexia, flatulence
and abdominal cramps.
Persisting for weeks months if untreated. Fever is not
Presence of trophozoites or cysts or both in diarrheal
In asymptomatic carriers only cysts are seen in formed
If microscopically stool is negative string test may be
METRONIDAZOLE OR quinacrine HCl
Use boiled, filtered, or iodine treated water.
No vaccination or prophylactic drug
Acid fast stain of stool sample
Endoscopic biopsy of small intestine
Immunofluorescence assay (IFA)
Enzyme linked immunoabsorbant assay (ELISA)
Polymerase Chain Reaction (PCR)
Test of choice
Cryptosporidium lives and grows in variety of animals–
geese to snakes to cows, sheep and pigs to humans.
Cryptosproridium completes its cycle in a single host.
The Species of Crypto known to infect humans is
Infectious agents are the OOCYSTS
In immunocompromised patients ID50 is about 10 to 30
Autoinfection takes place in 2 ways-
Merozoites attach to nearby epithelial cells and
thin walled oocysts excyst and continue to spread
infection within the body
A scanning electron micrograph of Cryptosporidium lining the
A scanning electron micrograph of a broken meront of
Cryptosporidium showing the merozoites within.
TRANSMISSION AND EPIDEMIOLOGY
Person to person (fecal-oral)
Animal to human
Contamination of water supplies (result of waste runoff)
*WATER-BORNE MOST COMMON*
Usually symptoms subside within 10 days
Cocktail therapy -used to treat symptoms but NOT THE DISEASE
Drugs include: letrazuril, azithromycin, paramycin, and hyperimmune bovine colostral
Wash fruits and vegetables
Avoid untreated water
Treat contaminated water
MAINTAIN PROPER HYGIENE!!