Medical parasitology : study of parasites that infect human, diseases caused by them, clinical picture, their diagnosis, treatment and prevention as well as controls.
It involves drug development, epidemiological studies and study of zoonoses.
To know various terms related to parasitology.
To know about general parasites and parasitic infections.
To get knowledge about laboratory diagnosis and its importance.
To gain idea about general epidemiological aspects of parasites that affect human.
Apply basic methods of specimen collection , preservation and processing in lab.
To prevent ourselves from these infections and apply control measures.
Department of Laboratory Medicine,
Nobel College of Medical Sciences,
Presented By : Group H
It is a golden opportunity for us to work on this
presentation titled as “PARASITOLOGY” to enhance
our speaking and presenting skills under the faculty
of BSc.MLT in Nobel College.The basic objective of
presentation is to gather knowledge about various
topics emphasizing on our course contents.
This presentation includes explanation on different
laboratory diagnosis, treatment, control of parasitic
For any project, essential requirement is correct
guidance and references. We are very thankful to
Mr.TapeshwarYadav sir who provided us this
opportunity and motivation to gain knowledge
through this presentation. We have got knowledge
about the way to search information, filter them and
utilize various resources for gathering information.
Some of the sources are: google scholar, slide share,
SCOPE AND IMPORTANCE
RELATIONSHIP OF PARASITES
CLASSIFICATION OF PARASITES
GENERAL STAINS ANDTHEIR PURPOSES
PREVENTION AND CONTROL
Scope And Importance
To provide knowledge on parasitic infections,
their diagnosis , prevent and control them
Know the lifecycle of specific parasites and
identify important parasitic agents affecting
Be able to prepare reagents necessary for
parasitological laboratory test
Apply necessary procedures for diagnosis of
parasites in laboratory
To know various terms related to parasitology.
To know about general parasites and parasitic
To get knowledge about laboratory diagnosis and
To gain idea about general epidemiological aspects
of parasites that affect human.
Apply basic methods of specimen collection ,
preservation and processing in lab.
To prevent ourselves from these infections and
apply control measures.
Parasitology: Scientific study of parasites, their hosts
and relationship among them.
Father of parasitology : Francesco Redi
Medical parasitology : study of parasites that infect
human, diseases caused by them, clinical picture, their
diagnosis, treatment and prevention as well as
It involves drug development, epidemiological
studies and study of zoonoses.
Parasites : organism which depends upon host
eg: Plasmodium vivax
Vector : living organism that carries a
disease-causing organism to new hosts
Host : organism on which
parasite is depended.
eg: human beings
Definitive host :Host in which the parasite
reaches maturity and reproduces sexually.
Intermediate host: Host in which a parasite
undergoes development but not sexual.
Symbiosis: living together where either one
or both are benefitted while none is harmed
Commensalism: one symbionts is benefitted
other is unaffected
Mutualism: both symbionts are benefitted
Parasitism: one symbiont is benefitted
whereas the next is damaged
Parasitic intestinal worms
Lacks digestive system
Reduced nervous system
Complex reproductive system( produce large no. of eggs)
Means of locomotion is reduced or complete lacking
An infection caused or transmitted by parasites
Source of infection
Eggs containing food ingestion
Penetration of intact skin or mucuos membrane
Mode of transmission
MODE OFTRANSMISSION DISEASES
FAECAL-ORAL ROUTE , INGESTION Ascaris, Balantidiasis, Giardia,Taenia,
VECTOR BORNE Kissing and hugging: Trypanosoma
Mosquito: Plasmodium, Wuchereria
Sand fly: Leishmania
Tsetse fly: Trypanosoma
SEXUAL CONTACT Entameoba, Giardia,Trichomonas
INHALATION Acanthameoba, Enterobius, Naegleria
CONTACT OF SKIN(PENETRATION) Ancylostoma, Necator, Schistosoma
CONTACT OF EYES(PENETRATION) Acanthamoeba
General Classification of
Ecto parasite: lives outside the host body
Endo parasite: lives inside host body (blood, tissues,
body cavities, digestive tract)
Temporary parasite: visit host for short time
Permanent parasite: throughout whole lifespan
Facultative parasite: on parasites when
Obligatory parasite: only on living host body
Wandering parasite: at place where it cant live
Occasional parasite: attacks on unusual host
1. The amount should be sufficient (4.0ml)
2. It should be collected in a non-absorbtive container
3. Stool sample should be examined as soon as
4. Sample should not be left exposed to air which
leads to drying of stool
5. Stool mixed with urine should never be accepted
for investigation (urine destroys trophozoite forms
6. While making smears, sample should be taken
from well inside formed stool and from mucus or
blood stained portions of loose stool
Normal color - presence of stercobilinogen
- light or dark brown
Abnormal stool colour seen in different disease condition
- Black : bleeding from upper gastrointestinal tract tumors
- Brighter : bleeding from lower gastrointestinal tract
- Blood and mucus : amoebic dysentery
- Clay coloured :post hepatic jaundice obstruction to the flow of
bile to intestine(biliary obstructions)
- Yellow or yellowish green – diarrhoea
- Maroon or pink –due to tumors, haemorhoids,tissue or
inflammatory processs from lower gastrointestinaltract
The normal sample may smell offensive but not excessively
foul, other can be described foul sour
Foul odor caused by the undigested protein and by
intake of carbohydrate
Offensive : amoebic dysentery
Nil : bacillary dysentery
Normally, there is 100 to 200 gm / day
Many disorders cause large bulky stools even in people who
Don’t eat a lot. Some gastrointestinal order also cause poor
food breakdown and absorption which leads to large, bulky
Normal stool is well formed .
Abnormal stool consistency seen in different physical and
pathological condition .
Stools may be loosely formed stools, Watery stools, Thin
stools, Dry and hard stools, Putty like stools,
Small round hard stool(habitual constipation),
Pasty stools, diarrhoeal stool are watery,
Steatorrhea stool are large in amount, forthy, foul
Constipated stools are firm and may be spherical masses
Ribbon like stool
Mucus is not present in normal stool .
Seen in amoeba of Giardia lamblia .
when urea gets high than the normal mucus can be seen in
It is also present in carcinoma condition.
Pure mucous ie. translucent gelatinous material clinging to
the surface of stool.
This may be seen in severe constipation, mucous colitis ,
excessive staining of stool, emotionally unstable patient
Mucus and diarrhoea with microscopically patient with RBCs
and WBCs is seen in bacilliary dysentary, ulcerative colitis,
intestinal tuberculosis, ameobiasis, enteritis, acute diverticulis,
ulcerating malignancy of the colon
This depends upon the dietary intake.
Normally, slightly acidic or alkaline pH (7.0 to7.5)
Alkaline pH :
Fat and carbohydrate mal-absorption
Glucose, fructose, galactose,etc are reducing
Lactose intolerance may occur after a prolonged
episode of viral gastroenteritis
Fructose not absorbed can cause a positive test for
reducing sugar in stool
Reducing subs. are reported as:
Negative –this is the normal result and means that the
body is digesting and absorbing sugars properly.
Positive- this means these are substances in the stool
that can act as reducing agents i.e. there are forms of
sugar in the stool that have not been absorbed by the
Presence of leukocytes
Presence of RBCs
Presence of ova and parasites
Presence of meat fibers and muscle fibers
Presence of fat
1. Presence of leukocytes
Normally there are no WBCs
Increase no of WBCs in stool
Chronic ulcerative colitis
Salmonella E.coli diarrhoea
Fistula of anus or rectum
WBCs may appear in
Absence of WBCs seen in
some of the diarrhoeal
‐ Viral diarrhoea
‐ Drug induced diarrhoea
‐ Amoebic colitis
‐ Non-invarsive diarrhoea
‐ Parasitic infestation
2. Presence of RBCs in the
Blood in the stool can be
Bright red: from the bleeding in the lower GI tract
Maroon in color
Black & tarry: from bleeding from the upper GI tract
Occult (not visible to naked eye)
Causes of blood in stool
3. Ova and parasites
Normally there are no parasites or eggs in the stool
Multiple stool sample are needed to rule out parasitic
infestation at least three consecutive days.
An abnormal results means parasites or eggs are
present in stool such infections include
- Roundworms: Ascaris lumbricoides
- Hook worms: Necator americanus
- Pinworms : Enterobius vermicularis
- Tapeworms: Taenia solium, Diphyllebothrium latum
- Protozoa : Entamoeba histolytica, Giardia lamblia
4.Presence of meat and muscle
Their presence show some defects in the digestion.
Increased amount of meat fibers are found in :
Pancreatic functional defect like cystic fibrosis
5. Presence of fat
The fat in the stool shows the possibility of :
Deficiency of pancreatic digestive enzyme
Deficiency of bile
Serological test becomes positive only in invasive amoebisis.
Various serological tests done include :
Indirect Hemagglutination (IHA)Test:
Serum with antibody titer of 1:256 or more by IHA Is diagnostic
of amoebic hepatitis.
Latex agglutination test
Enzyme-linked immunosorbent assay (ELISA):
Commercially available tests that use ELISA to detect
Entamoeba antigens (E. histolytica)
Greater sensitivity than microscopic test
It is a sensitive method in diagnosinf chronic
and asymptomatic intestinal amoebiasis.
Media used for stool culture:
Boeck and Drbohlav media
NIH polygenic media
Faecal Occult Blood Test
Generally, stool of normal person doesn’t contain
It may be present due to various pathological and
In some cases, very scanty blood may be present
and can’t be detected by physical appearance.
This test is used to detect trace amount of blood in
stool for which various chemicals are used.
− Normal range (600-2000ml)
− Polyuria : more than 2500ml (within 24 hours)
− Oliguria : less than 500ml urine day
− Anuria : complete suppression of urine formation
COLOUR AND ODOR
- light yellow to pale yellow or white clear
- concentration of urochrome pigment.
− Diet, medicines and various chemical disease can affect
− Urine becomes more ammonia-like due to bacterial
− Ranges from 4.5 -8.0, average :6.0( i.e.slightly acidic)
− High protein intake : acidic urine
− High vegetative diets and bacterial infections : alkaline
− In case of UTI urine is acidic in case of infection with E.coli
Normal range : 1.003- 1.035 gm/cm^3
Measurement of density of urine
high specific gravity: Diabetes mellitus, adrenal abnormalities
or excessive water loss, diarrhoea or kidney inflammation
low specific gravity: Diabetes insipidus, excessive water intake,
chronic renal failure
− Normal urine is usually clear
− Cloudy: presence of amorphous phosphate
− Turbid : presence of WBC / epithelial cells and bacteria
− Milky : presence of fat
In case of WBC, amorphous phosphate epithelial cells,
sediments formation occurs at the bottom of container.
‐ Normal urine is transparent or clear
‐ Cloudy urine may be evidence of phosphates, ureates,
mucus, bacteria, epithelial cells or leukocytes
- Measured in urine by testing for the presence of albumin
- (Proteinuria): indicator of kidney disease,bladder or
kidney stones, multiple myeloma, haemolytic anaemia
Uncontrolled diabetes, kidney/hormonal disorders,
-indicate that fat is being metabolished instead of
carbohydrate for energy
-raised ketones indicate diabetic condition
+ve test: hepatitis / cirrhosis of the liver
Urobilinogen result is compared with the bilirubin result
A negative test for bilirubin but positive for urobilinogen
can indicate haemolytic.
A lower negative test result for urobilinogen in a patient
with positive bilirubin test indicate hepatic obstruction.
A waste product created when old RBCs are broken down,
usually removed as component of bile
A positive test for bilirubin is an early indicator of hepatitis,
liver disease or jaundice
Urine normally contains a small amount of
A slight increase in haemoglobin can be significant in
terms of potential causes such as a urinary tract
infection, kidney disease, trauma, strenuous exercise.
Indicator of presence of a range of bacteria that can
cause a urinary tract infection
Significant increase in level of leukocyte indicates
inflammation of the kidney/urinary tract or
RBCs: Its no. elevation indicates injury,
inflammation, disease/infection of the urinary
WBCs: indicate infection or inflammation in
-Transitional: indicates an infection in bladder
-Squamosal :indicates an external urethra
-Kidney cell indicates a kidney conduction
-Trichomonas: responsible for vaginal infection
-Yeast :indicates a vaginalyeast infection
-Bacteria: cause urinary tract infection, kidney
-Casts: indicate kidney disorder
-Crystals: abnormal crystal cuase pain and
damage to the urinary tract such as: cystene,
Fixed in methanol
To examine parasitemia and recognize them and their parasitic
form like : schizont, gametocytes
Not fixed in methanol
RBCs to be hemolysed
Leukocytes and many malarial parasites present will be the only
Mainly used to detect infection and to estimate parasitemia
Stains used for thick and thin
These stains allows for the detection of
WBCs, RBCs and platelet abnormalities
1. Put a small drop of blood on a clean glass slide and
spread using a spreader , making an angle of 35-40 . A
tongue shaped smear should be made
2. After drying and proper labelling of smear , fix with
methanol for 5-10 minutes
3. Stain with 1:10 diluted Giemsa stain for 45 minutes
4. Wash with tape water , allow to dry and examine
1. Place a drop of blood on a clean glass slide
2. Spread in an area a half – inch square or diameter
with the help of a needle or the corner of another
3. After drying , dehaemoglobinize with distilled
water or acetic tartaric acid solution or 2 % acetic
acid solution until the smear appears greyish –
4. Drain off the excess dehaemoglobinize agent and
fix with methanol for about 5 minutes (when using
acetic acid tartaric acid solution , the smear should
be treated with slightly alkaline water to remove or
neutralize the excess of acid.
Prevention & Control
In endemic areas, people should be educated
about the dangers of eating raw or under cooked
Filtration of water is must
Improve the water supply in affected
Animal wastes and feces should be disposed in
sanitary way out of reach of water resources
Wash your hands regularly especially after
handling uncooked food or feces
Keep your fingernails short and scrub under them
with a nail brush.
In public toilets, don't sit on a bare toilet seat
without protecting it with paper; squat if possible.
Pinworm eggs and Trichomonas can be present
on toilet seats.
Trichomonas can also be spread through mud or
water baths, or from sauna benches.
Avoid walking barefoot, especially in warm, moist
Don't use tap water to clean contact lenses - use
sterilized lens preparations.
Use a shower filter or bath-water filter.
-Don’t eat or drink in lab
-Wear coverings like: apron, gloves, proper shoes
-Don’t clean up with hand if spilled
-Mouth pippetting is avoided
-Don’t taste any chemical substances
-Clean work area and hand when work is finished
-If chemicals come in contact with skin clean
immediately and inform lab instructors