PARASITOLOGY

Mrs. Mehwish Zeeshan

Parasites:
A living organism which
receive nourishment and
shelter from another
organism where it lives.

Parasitology:
The study of the parasites of
man and their consequences
is called parasitology.
Parasitism: Zoonosis
• A parasite is an organism that is This term is used to describe an
entirely depend on another organism, animal infection that is naturally
referred to as its host, for all or part of transmissible to humans either
its life cycle and metabolic directly or indirectly via a vector.
requirement.
• Parasitism is therefore a relationship in Examples: Leishmaniasis
which a parasite get benefits and the Trypanosomiasis,Plasmodium
host provides benefits. (Malaria), etc.
Non- Pathogenic Parasites:
They do not harm the body, and cause illness even in people
with weak immune systems.
Pathogenic Parasites:
Parasites that cause harm to the host.
Vector:
It is an agent usually insect, that transmit an infection from
one human host to another
OR
A vector which assists in the transfer of parasitic forms
between hosts.

Parasitic Infection:
Invasion by endo-parasites (Protozoan and Helminthes)

Parasitic Disease:
Invasion and pathology produced by endo-parasites. Both
parasitic and host factors are involved.
 Types of Parasites
1. Ecto- parasite (Ectozoa):
Lives outside on the surface of the body of the host.
2. Endo – parasite (Entozoa):
Lives inside the body of the host; in the blood, tissues, body cavities, digestive tract
and other organs.
3. Temporary or intermittent Parasite:
Visit its host for a short period.
4. Permanent Parasite:
Leads a parasitic life throughout the whole period of its life.
5. Facultative Parasite:
Lives a parasite life when opportunity arise.
6. Obligatory Parasite:
Cannot exist without a parasitic life.
7. Occasional or Accidental Parasite:
Attacks on different from its normal one host, usually they do not survive in the
wrong host
8. Wandering or Aberrant Parasite:
Happens to reach a place where it cannot live.
HOST: An organism which 3. Reservoir Host:
harbours the parasite.
This is an animal host serving as a
CLASSES OF HOST: source from which other animals
can become infected.
1. Definitive Host:
Epidemiologically, reservoir hosts
The host in which sexual reproduction are important in the control of
takes place or in which the most parasite diseases.
highly developed form of a parasite
occurs. The definitive host is the
mammalian host. 4. Paratenic Host (A carrier or
transport host):
2. Intermediate Host: A transport host, but the parasite
The host which alternates with the does not require it to complete its
definitive host and in which the larval life cycle.
or asexual stages of a parasite are
found. Some parasite require two
intermediate hosts in which to
complete their life cycle.
 Transmission of Parasites
1. Inadequate sanitation and unhygienic living conditions leading to feacal contamination
of the environment.
2. Lack of health education
3. Insufficient water and contaminated supplies.
4. Failure to control vectors due to ineffective interventions, insecticide resistance, lack of
resources, and suppression of surveillance and control measures
5. Poverty, malnutrition, and for some parasites, increased susceptibility due to co-existing
HIV infection.
6. Development schemes introducing opportunities for vector breeding and infection of
the workforce e.g. dam projects
7. Failure of drugs to treat parasitic infections effectively
8. Climatic factors
9. Population migrations causing poor health, loss of natural immunity, exposure to new
infections, and people being forced to live and work closer to vector habits and
reservoir hosts, often in overcrowded conditions ,e.g. refugee camps.
 Life Cycles of Parasites
Life Cycle:
In order to survive from one generation to
the next, parasites have a series of distinct
developmental stages and hosts
collectively known as a life cycle.

Significance:
• To prevent the spread of parasitic disease
and in selecting and evaluating control
interventions.
• It also provide information on the tissues
infected and the parasitic forms that can
be found in specimens from patients.
• It has two (02) types:
1. Direct Life cycle: 2. Indirect Life Cycle:
When a parasite requires only one species of host When two or more species of host s are required, the
in which to complete its development it is life cycle is referred to as indirect life cycle. Important
said to have a direct life cycle. Important parasites in humans that have a direct life cycle
parasites in humans that have a direct life include:
cycle include:
Examples:
Examples: 1) Plasmodium species 2) Trypanosoma species
1) Entamoeba histolytica 3) Leishmania species 4) Wuchereria bancrofti 5)
2) Giardia lamblia Loa loa 6) Onchocerca volvulus
3) Ascaris lumbricoides 7) Paragonimus westermani
4) Entrobius vermicularis 8) Schistosoma species 9) Taenia species
5) Strongyliod stercoralis 10) Fasciolopsis buski 11)Diphyllobothrium
6) Trichuric trichiura
7) Ancylostoma duodenale
8) Necator americanus
 Classification of Parasites
Parasites
1. Protozoa 2. Metazoa
a. Sarcodina a. Platyhelminthes
b. Mastigophora 1. Trematoda
2. Cestode
c. Ciliata b. Nemathelminthes
d. Microsporidia
e. Coccidia
 1. Protozoa (Unicellular)
a. Sarcodina (Amaoeba) b. Mastigophora
• Entamoeba histolytica (Flagellates)
• Acanthamoeba • Giardia lamblia
species • Trichomonas vaginalis
• Naegleria species • Trypanosoma species
• Leishmania species
c. Ciliata (Ciliates) e. Coccidia
a. Blood and tissue Coccidia:
1. Plasmodium species
• Balantidium coli 2. Toxoplasma gondii

d. Microsporidia: b. Intestinal Coccidia:

1. Isospora belli
2. Cryptosporidium parvum
• Encephalitozoan species 3. Cyclospora cayetanensis
• Enterocytozoon species
 Metazoa (Multicellular)
Platyhelminthes (Flat worm)

Trematoda (Flukes)
• Shistosoma species
• Paragonimus species
• Fasciolapsis buski
• Clonorchis sinensis
• Opisthorchis viverrini

Lesser medical importance

• Metagonimus yokagawai
• Heterophyes heterophyes
• Dicrocoelium dendriticum
b. Cestodes (Tape worm):

1. Taenia species
2. Echinococcus granulosus
3. Diphyllobothrium latum

Less important:
1. Hymenolepis nana
 B. Nemathelminthes
(Nematodes or Round worm)
Filarial and other tissue
Intestinal nematodes:
nematodes:
1. Ascaris lumbricoides
1. Wuchereria bancrofti
(Large round worm)
2. BrugIa species
2. Entrobius vermicularic (Thread
worm) 3. Loa loa
3. Trichuris trichiura 4. Onchocerca volvulus
(Whip worm) 5. Drancunculus medinensis (Guinea
worm)
4. Strongyloides stercoralis
6. Trichinella species
5. Ancylostoma duodnale
(Hook worm)
6. Necator americanus
(Hook worm)
 Intestinal, Urogenital,
Blood and Tissue Protozoa’s

Ms. Mehwish Zeeshan

Intestinal Protozoa’s

Ms. Mehwish Zeeshan

 Intestinal Protozoans
1. Entamoeba histolytica (Belongs to Sarcodina)
Morpholog Life Cycle
y
 Intestinal Protozoans
2. Giardia lamiblia
(Belongs to Mastigophora)
 Intestinal Protozoans
3. Crytosporidium parvum
(Belongs to sporozoa/coccidia)
Parasites Transmission Diseases Clinical Findings

Entamoeba histolytica Oral – feacal route Amoebic dysentery Fever, lower

(Cyst) (bloody foul smell) abdominal pain,
Liver abscess Flatulence, etc.

Giardia lamblia oral – feacal route Giardiasis, Diarrhoea Malasie, Weight

(Cyst) (non-bloody foul loss,Abdominal
smell) cramps, Nausea,
etc.

Cryptosporidium Oral – feacal route Crytosporidiosis Diarrhoea (1-2

parvum (Oocyts) weeks), severe in
old persons.
Parasites Pathogenesis
Entamoeba Amoebic Dysentery: It occurs Amoebic Liver Abscess: A liver abscess
histolytica when the trophozoite invade the is a pus-filled mass inside the liver. Liver
wall of the large intestine and abscesses generally result from spread of
multiply in the submucosa, there infection from the digestive tract via the
trophozoite secretes enzymes due portal vein from the base of an amoebic
to which inflammation & necrosis ulcer in the large intestine. The
occurs & form lesion, these lesions trophozoites multiply and proceed to carry
reaches to muscularis mucosa & on their cytolytic action. Which causes
forming large flask-shaped or tear obstruction to the circulation and produce
drop ulcers. The amoeba ingest thrombosis of the portal venules resulting in
red cells from damaged capillaries. necrosis of the liver cells.
Giardia lamblia With the help of sucking disc the trophozoite attaches itself on the convex
surface of the epithelial cells in the intestine and may cause irritation and low
grade inflammation of duodenal or jejunal mucosa, associated with crypt
hypertrophy, villous atrophy, & epithelial cells damage. Leading to malabsorption
of fat. The parasite also capable of producing harm by itself toxic effect (allergy),
traumatic and irritative effect as well as by spoliative action.

Cryptosporidium The oocyst excyst in the small intestine, where the trophozoites attach to the gut
parvum wall but not invade. The pathogenesis of diarrhea is unknown no toxin has been
identified.
 Laboratory Diagnosis
Specimen Collection
• Collect the stool in a dry, clean, leak proof
container. Make sure no urine, water, soil or
other material gets in the container.

• This table demonstrates the distribution of

protozoa in relation to stool consistency and
should be taken into consideration when
specimens are received.

• Fresh stool should be examined, processed,

or preserved immediately.

• An exception is specimens kept under

refrigeration when preservatives are not
available; these specimens are suitable for
antigen testing only.
• Preserve the specimen as soon as possible. If using a commercial
collection kit, follow the kit’s instructions.

• If kits are not available, the specimen should be divided and stored in
two different preservatives, 10% formalin and PVA (polyvinyl-
alcohol), using suitable containers. Add one volume of the stool
specimen to three volumes of the preservative.

• Insure that the specimen is mixed well with the preservative. Formed
stool needs to be well broken up.

• Certain drugs and compounds will render the stool specimens

unsatisfactory for examination.

• The specimens should be collected before these substances are

administered, or collection must be delayed until after the effects have
passed. Such substances include: antacids, kaolin, mineral oil and
other oily materials, non-absorbable antidiarrheal preparations,
barium or bismuth (7-10 days needed for clearance of effects),
antimicrobial agents (2-3 weeks), and gallbladder dyes (3 weeks).

• Specimen collection may need to be repeated if the first examination is

negative. If possible, three specimens passed at intervals of 2-3 days
should be examined.
 Staining Procedures
• used for identification of protozoan trophozoites and cysts
and for confirmation of species
• It provides laboratories with a permanent record
• The slides can be sent to a reference laboratory when
organisms with unusual morphology are encountered, or
when identification is difficult

Problems encountered in the staining of protozoan cysts:

• The specimen is too old
• The smears are too dense
• The smears are allowed to dry before fixation or fixation is
inadequate.
Microscopic Examination of Feacal Material

WET MOUNT
Iodine stained STAINED SMEAR
1. WET MOUNT PREPARATION 4. Modified Acid-Fast Staining:
• It is a fast, simple procedure and To identify the oocysts of the
provides a quick answer when coccidian species
positive. (Cryptosporidium, Cystoisospora,
• It estimate the parasitic burden and Cyclospora), which may be
difficult to detect with routine
2. IODINE PREPARATION: stains such as trichrome.
• This simple stain is used to identify
cysts of amoebic and flagellated
protozoa and is usually sufficient for 5. Trichrome Staining:
diagnostic purpose. It is a rapid, simple procedure,
• Examine Nuclear structure of cysts stained smears of the intestinal
protozoa, human cells, yeast, and
3. Iron haematoxylin stain: artifact material.

To identify the nuclear structure of

protozoan's. 6. Chromotrope Staining: to
differentiate microsporidia spores
from background fecal elements.
 STOOL CONCENTRATION METHOD
Concentration method used for the diagnosis of helminthic eggs and
may also some protozoal cysts.
Types: i. Floatation Technique
ii. Sedimentation Technique
Floatation Technique:
USES:
• The faecal material is dissolved in solution of a higher density than that of the
eggs. In this case the eggs float in the superficial portion if the fluid.
• It has been observed that all the helminthic eggs float in such a solution
except the following:
(i) unfertilized eggs of A. lumbricoids,
(ii) eggs of T . Saginata and T . Solium and
(iii) eggs of all intestinal flukes.
• The strongyloides larvae do not float in salt solution
TYPES:
(a) Simple Floatation Technique
(b) Lane’s Direct centrifugal Floatation Technique
(c) Zinc sulpahte floatation technique

(2) SEDIMENTATION TECHNIQUE:

Uses:
The faecal material is dissolved in water or solution of a density below that of
the eggs. In this case the eggs are concentrated at the bottom.
Types
(a) Simple Sedimentation
(b) Formal – saline Ether Sedimentation Method
 Detection of Parasite Antigens
• The diagnosis of human intestinal parasites depends on
microscopic detection of the various parasite stages in
feces, duodenal fluid, or small intestine biopsy specimens.
• Parasitic antigens is detected by
i. Complement fixation test
ii. Precipitin test
iii. Floculation test
iv. Agglutination test
v. Direct flourescent antibody test
vi. Enzyme Immunoassay test (EIA)
• Intradermal Reaction (Skin Test):

This is positive in many helminthic infection and also in in certain

protozoal infection.

Molecular Diagnosis
• the stool specimen can be analyzed using molecular
techniques such as
i. polymerase chain reaction (PCR).
ii. PCR amplified fragments can be analyzed by using
restriction fragment length polymorphisms (RFLP)
iii. DNA sequencing if further characterization is needed.
 Parasites Treatment Prevention

Entamoeba Metronidazole, Avoiding fecal contamination of food & water, good

histolytica Iodoquinol personnel hygiene, purification of municipal water
supplies, use of night soil for fertilization of crops,
vegetables should be cooked.

Giardia lamblia Metronidazole, Drinking boiled, filtered water in endemic areas & while
Quinacrine. hiking.

Cryptosporidium Spiramycin, Avoidance of animal feaces for contamination and

parvum paromomycin, careful sanitation are required..
nitazoxanide
Urogenital Parasite
Parasites Transmission Diseases Clinical Findings
Trichomonas Habitat: Trichomoniasis In Females:
Frothy yellow or cream-colored
vaginalis Genital Tract of both
vaginal discharge. Vulvular itching
male & female. & burning, Dysuria, Vaginal &
• Transmitted by cervical mucosa is tender,
sexual contact, The redened, & eroded & petechial
primary locations of hemorrhages seen.
the organism are
the vagina & the In Males:
prostate. May be asymptomatic, & serve as
a carrier. In symptomatic cases,
prostate, seminal vesical & urethra
may be infected. Thin, white
urethral discharge, Dysuria.
Blood & Tissue Parasites
Blood Protozoans:
• Tissue Protozoans:
1. Plasmodium (sporozoan)
a. vivax a. Toxoplasma gondii (sporozoan)
b. ovale
c. malariae
d. falciparum

2. Trypanosoma (flagellate)
a. cruzi
b. gambiense
c. rhodesiense

3. Leishmania (flagellate)
a. donovani
b. tropica
c. mexicana
d. braziliensis
Parasites Transmission Diseases Clinical Findings
Plasmodium Via bite of Female Malaria; quartain 1.Cold stage: Sensation of
malariae Anopheline malaria, nephrotic cold, shivering lasting from15
Mosquito, syndrome mins to 01 hour.
Across 2. Hot Stage: Fever,
Plasmodium Malaria; benign headaches, vomiting; seizures
vivax Placenta, tertian malaria, in lasts for 1-6 hours. Timing of
Blood Relapses, fever cycle of P.malariae is 72
Transfusion, spleenomegaly hour, and P.vivax, P.ovale, and
Plasmodium I/V drug abusers Malaria; Malignant P. falciparum is 48 hrs.
falciparum tertian malaria, 3. Sweating stage: Occurs
Pernicious malaria, after 1- 6 hours, profuse
Black water fever, and perspiration, return to normal,
Cerebral malaria, temperature, tiredness
Acute renal failure, • Hemoglobinuria
severe anemia, or
•Abnormalities in blood
adult respiratory coagulation and
distress syndrome, thrombocytopenia,
Pulmonary edema
•Cardiovascular collapse and
shock
Plasmodium Malaria; benign
ovale tertian malaria,
Relapses
Morphology of Plasmodium
LIFE CYCLE OF PLASMODIUM
Parasites Laboratory diagnosis Treatment Prevention
Plasmodium Specimens: Blood,Serum, • Chloroquine: • Case management (diagnosis
malariae Urine Sulfadoxine- and treatment) of patients
2. Microscopy: Leishman’s pyrimethamine suffering from malaria
Plasmodium (Fansidar®)
vivax stain, Field’s stain, Geimsa
• Prevention of infection through
Stain
Plasmodium • Mefloquine vector control
b- Blood Films:
falciparum (Lariam®)
1. Thin Smear (species
• Prevention of disease by
Plasmodium identification). • Atovaquone- administration of anti-malarial
ovale 2. Thick Smears (screen the proguanil drugs to particularly vulnerable
presence of plasmodium). (Malarone®) population groups such as
Note: only small trophozoites, pregnant women and infants.
Large trophozoites, blood • Quinine
schizonts and Gametocytes of • Prophylactic Drugs
plasmodium species are seen • Doxycycline &Vaccination
with the exceptions of Large
• Indoor Residual Spraying
trophozoite and blood • Artemisin
schizonts of P.Falciparum derivatives (not
• PCR, urine analysis, licensed for use • Mosquito nets and bedclothes
in the United
serological test.
States, but •Drainage of stragnant water to
often found reduce the breeding areas
overseas)
Parasites Transmission Diseases Clinical Findings

Trypanosoma It is divided into Africa Chancre (painful swelling), High

brucei subgroup i.e. trypanosomiasis irregular fever with shivering,
rhodesiense & (African sleeping sweating & increased pulse rate
sickness).
gambiense Persistent headache usually
pain in necks, shoulders, &
T.b.rhodesiense Tsetse fly species: Acute sleeping Calves, Lymphadenapathy,
Glossina palpalis sickness
Spleenomegaly, Trembling
Glossina tachinoids Meningeoencephalitis, Inability
T.b.gambiense Tsetse fly specie Chronic sleeping to speak properly, Progressive
Glossina morsitans sickness. mental dullness, Excessive
Glossina pallidipes Sleeping,Oedema of the limbs If
untreated, coma develops &
finally death

Trypanosoma mainly transmitted South American Fever, Malaise,

cruzi with the faeces of trypanosomiasis or lymphadenopathy,Conjunctivitis,
an infected bug Chagas’ disease meningo-encephalitis or
(Reduviidae), ,
myocardial Failure heart block,
SubfamilyTriatominae. paralysis, Megaoesophagus,
blood transfusion, megacolon

Transplacental
Trypanosoma and Leishmania
Parasites Laboratory diagnosis Treatment Prevention

Trypanosom Sample: Blood, bone marrow, Pentamidine & vector is kill by the use of
a brucei lymph node aspiration, CSF. Suramin insecticides.

T.b.rhodesie Microscopy: Arsenicals

nse Examine Blood, bone marrow, (Tryparasamin Isolation of the human
population from areas known to
lymph node aspiration, CSF: melarsen,
T.b.gambien harbour infection games &
se For Trypanosomes, raised melarsoprol &
treatment of all infected humans.
Protein & IgM, Measurement trimelarsen.
Of haemaglobin, reduced Nitrofurazone Chemotherapy: Pentamidine is
Platelet numbers, moderate (furacin)
effective against gambiense
leucocytosis with monocytosis, disease.
lymphocytosis & plasma cells.
Trypanosom Sample: Blood Nitrofurazone - Using Insecticides & use of
a cruzi Microscopy: stained blood tablet (dosage building material which are
film for trypomastigote form. 18.375gm in 27 impermeable to the bug.
days).
Other Tests: - Using fumigant canisters to
Xenodiagnosis, Intradermal control vector
test; Biopsy of lymph node or - Removal from houses of
muscle may reveal amastigote reservoir animals which could
Form, Lymphosytosis with harbour T.cruzi.
atypical mononuclear cells - Screening of donor blood for
T.cruzi.
Parasites Transmission Diseases Clinical Findings
Leishmania Sandfly Visceral Irregular fever, Spleenomegaly
donovani leishmaniasis also Hepatomegaly,Lymphadenopathy
called Kala-azar Hyperpigmentation of skin (black
sickness), Diarrhoea, Low WBCs
& Platelet count, Anemia Epitaxis
(nose bleeding), Bleeding from gums,
Occasionally kidney Damage
Leishmania also by Sandfly & Cutaneous Red papule is formed at the bite
tropica contamination of the leishmaniasis also site, Reignol lymphadenopathy
abraded skin with the called Oriental Papule enlarge slowly to form
sore
infected material by multiple satelite nodules that
direct contact does coalesce & ulcerate If cellular
produce the infection, immunity does not develop lesion
spread to large areas of skin
Leishmania By sandfly Mucocutaneous Severe cutaneous leishmaniasis.
brasiliences (anthropophilic). Direct leihmaniasis also Lesions are similar as oriental sore &
conatct play a vital called Espundia. resulting ulcers, Metastatic lesions
role in transmission of occur, usually Mucocutaneous
an organism junction of nose & Mouth, inadequate
Treatment cause secondary bacterial
infection.
Parasites Laboratory diagnosis Treatment Prevention
Leishmania Samples: Pentavalent Protection from sandfly bites,
donovani L.donovani: Lymph node (urea stibamine, by the use of netting, protective
aspirate, blood & spleen, liver & Sodium clothing, insect repellents.
or bone marrow puncture Stibogluconate)
biopsies Synthetic non Insecticide spraying
L.tropica: Lymph node Metallic drug
aspirates, scrapings, & (Pentamidine Eliminate the reservoir hosts.
biopsies from margon of isethionate)
lesions. Pentavalent
Leishmania
tropica L.brasiliensis: Scraping or Drug
biopsy of skin & Dehydroemetine,
mucocutaneous lesions
Leishmania Microscopy: Giemsa stained Pentavalent drug
brasiliences smears & sections: for In resistant
amastigote forms. cases,pyrimeth
- Formal gel (aldehyde) test; to mine or
detect marked increase in IgG amphotericin B
polyclonal non-specific Cycloguanil
- Leishmanin skin test: pamoate in oil.
Parasites Transmission Diseases Clinical Findings
Toxoplasma Infection of humans beings with the Toxoplasmosis, 1. Congenital toxoplasmosis is
ingestion of cysts in undercooked including generally fatal and lesions are
gondii widespread, having a special prediction
meat or from contact with cat feces. congenital
toxoplasmosis for the developing nervous system of
the foetus.
Human toxoplasmosis may occur in
two ways; 2. Acquired toxoplasmosis may be
1.Congenital; grouped as follows:
a. Cerebrospinal toxoplasmosis
Foetus is infected in utro through the b. Toxoplasmosis in Eyes
transplacental route c. Toxoplasmosis in Lymphatic's
2. Acquired: e.g, by ingestion of d. Toxoplasmosis in Skin
underdone meat, by inhalation (Exanthermatous)
(droplet infection), By inoculation e. Toxoplasmosis in lungs
f. Toxoplasmosis in Heart
(through skin). g. toxoplasmosis in Liver and Spleen
h. Toxoplasmosis in uterus
Habitat:
Definitive host are domestic Cats &
Intermediate Host are humans &
other mammals
PLATYHELMINTHES (Cestodes & Trematodes)
NEMATHELMINTHES

Mrs. Mehwish Zeeshan

AHS
 Medical Important Cestodes

1. Diphyllobothrium
Latum
2. Taenia species i.e.
T. saginata &
T. solium
3. Echinococcus
granulosis
4.Hymelopsis nana
Parasites Transmission Diseases Clinical Findings
Taenia solium a) Ingest larvae in undercooked Taaeniasis (Adult worm) Most patients are
(pork tape worm) pork containing the larvae called Cysticercosis (larvae) asymptomatic, but
cysticerci. anorexia, diarrhea occur.
b) Ingests the worm eggs in food or Cystecercosis in brain
water contaminated with human causes headache,
feces. vomiting, seizures, uveitis
or retinitis in eyes,
subcutaneous nodules.

Taenia saginata eating raw or undercooked beef Taeniasis Abdominal discomfort,

(beef tape worm) (Cysticercus bovis; larvae). chronic indigestion,
Diarrhoae with later
constipation, anemia.

Diphyllobothrium Oral – feacal route Diphyllobothriasis Epigastric pain, abdominal

latum (Plerocercoids ingested in fish) cramps, Megaloblastic
anemia

Echinococcus Oral – feacal route (eggs) Echinococcossis, Hepatic dysfunction, erode

granulosis Hydatid cyst in bronchus, cerebral cyst,
superfacial cyst, etc.

Hymenolopsis Oral – feacal route Hymenolepiosis Abdominal pain, anorexia,

nana (eggs), Internal autoinfection, itching around the anus,
diarrhoea, allergic
reactions.
Parasites Lab Diagnosis Treatment Prevention
Taenia solium Proglottids & eggs in Praziquantel, It involves cooking pork adequtely &
stool, cycticercosis cyst albendazole, but in disposing waste properly so that pigs
in tissues, ELISA detect some cases surgical cannot ingest human feces.
antigens. excision may be
necessary.
Taenia Proglottids in stools, Niclosamid Cooking beef adequately, Disposing of
saginata eggs found in stool. Praziquantal waste properly so that cattle cannot
consume human feaces.

Diphyllobothri Eggs (oval,yellow Mepacrine (atebrin) Polluted water: Efficient disposal of

um latum brown ) with operculum Diclorophen sewage.
at one end in stool. Niclosamide (Yomesan) The fish should be cooked thoroughly
before eat.
Echinococcus Brood capsule Albendazole, Prevention of infection of dogs and the
granulosis containing multiple protoscolidal deworming of dogs, Clearing of hands
protoscoleces are agent hypertonic saline, before Eating, Laboratory workers
seen. should guard against pollution of fingers
should be injected into
the cyst to kill the while examine digs feaces.
organism and
prevent & accidential
dissemination

Hymelopsis Eggs and six-hooked Praziquantel, Avoidance of feacal containing food and
nana larva are seen in stool Niclosamide water
Good personal hygein
 MEDICAL IMPORTANT TREMATODES
Trematoda (Flukes)
• Shistosoma species
• Paragonimus species
• Fasciolapsis buski
• Clonorchis sinensis
• Opisthorchis viverrini

Lesser medical importance

• Metagonimus yokagawai
• Heterophyes heterophyes
• Dicrocoelium dendriticum
Parasites Transmission Diseases Clinical Findings
Schistosoma Schistosomiasis; Dermatitis, fever, urticaria,
haematobium affects urinary system hepatomegaly, palpable spleen,
painful hematuria, frequency of
Via feacal-dermal route
micturation increased, pain in
or via urinal-dermal
bladder region, granuloma
route (fork tailed
cercariae penetrate in formation in the bladder and later
the skin) fibrosis and calcification.

Shistosoma Sigmoido-rectal area affected,

mansoni Affects dysentry, ectopic lesions,
gastrointestinal tract hepatomegaly, peripheral cirrhosis,
portal hypertension

Schistosoma ileo-ceacal region affected,

japonicum dysentery, peripheral cirrhosis,
hepatic fibrosis, spleenomegaly,
oesophagela varices, brain and
lungs also involved.

Paragonimus Transmitted by eating Lung fluke causes, Within the lungs, worms exists in a
westermanni raw or undercooked paragonimiasis fibrous capsule that communicate
crab meat or cray fish with a bronchioles. Chronic cough
containing encysted with bloody sputum, Dyspnea,
larvae (metacercariae). pleuritic chest pain, recurrent
attacks of bacterial pneumonia &
resemble to tuberculosis
Parasites Laboratory Treatment Prevention
Diagnosis
Schistosoma Specimens: Urine, Nitrothinzole Prevention of Pollution of water with
haemaobium feaces, blood, biopsies, compound (niridazole, human excreta.
from bladder wall, rectal nilodin, hycanthone)
wall and liver. Destruction of the snail vector in
Shistosoma
Microscopy: Trivalent antimony endemic areas.
mansoni
Urine for S. compound (tartar
haematobium, or feaces emetic, fouadin, Avoidance of swimming, bathing, or
Schistosoma for S. mansoni & S. anthiomaline) washing in infected water.
japonicum japonicum for eggs.
Biopsy of vesical mucosa Praziquantal
(S.haematobium) or rectal
tissue for (S. mansoni &
S. japonicum) for
histological exam.
Aldehyde test for globulin
levels
Fairley’s test for cercarial
antigens (intra dermal
test)

Paragonimus Typical operculated eggs Praziquantal Cooking crabs properly is the best
westermanni in sputum or feces are method of prevention.
seen
 MEDICAL IMPORTANT NEMATODES
Intestinal nematodes:
1. Ascaris lumbricoides
(Large round worm)
2. Entrobius vermicularic (Thread
worm)
3. Trichuris trichiura
(Whip worm)
4. Strongyloides stercoralis
5. Ancylostoma duodnale
(Hook worm)
6. Necator americanus
(Hook worm)
Filarial and other tissue
nematodes:
1. Wuchereria bancrofti
2. BrugIa species
3. Loa loa
4. Onchocerca volvulus
5. Drancunculus medinensis (Guinea
worm)
6. Trichinella species
Parasites Transmission Diseases Pathogenesis /
Clinical Findings
Ascaris lumbricoides Oral – feacal route, Ascariasis, Intestinal Pneumonia, blood
inhalation of desiccated blockage, tingged sputum, night
eggs in dust Pneumonitis (larvae) blindness, GI ulcer,
ectopic ascariasis,
larvae reach to brain,
spinal cord, heart, and
cause disturbances.
Ancylostoma Feacal- dermal route Ancylostomiasis, Dermatitis, creeping
duodenale / (eggs passed in feaces Microcytic eruption, bronchiotis,
Necator americanus & filariform larvae hyochromic anemia epigastric tenderness,
penetrate skin) constipation, pluffy face
with swell eyelids,
edema of feet & ankle,
protuberant abdomen
Strongyloides Oral – dermal route Strongyloidiasis, Skin lesions, pulmonary
stercoralis (filariform larvae Malabsorption, lesions, intestinal
penetrate skin), Dysentery lesions, leucocytosis,
autoinfection.
Entrobius Peri-anal route, Enterobiasis Perianal pruritis,
vermicularis Autoinfection, Retro- eczematous in perianal
infection, persons to reigon, salpingitis,
persons transmission noctural enuresis,
appendicitis, secondary
bacterial infection
Parasites Lab Diagnosis Treatment Prevention
Ascaris Oval eggs with an Mebendazole Proper disposal of humans feaces.
lumbricoides irregular surface or Pyrantal pamoate Treatment of parasitized individuals.
adult worms are Piperazine Personal hygiene.
seen in stool.
Levamisole

Ancylostoma Eggs in stool, ocult Tetrachlorethylene

duodenale / blood in stool is Bephenum
Necator frequent.Eosinophilia hydroxynaphthoate,
americanus is present. Pyrantel Pamoate, Treatment of carrier and diseased
Mebendazole persons.
prevention of soil-pollution by proper
Strongyloide Larvae rather than Thiabendazole control of sewage disposal. Personal
s stercoralis eggs in stool. ELISA protection, wearing of boots and
detect antibody of gloves.
larval antigen.

Entrobius Scotch Tape Piperazine salts, Prevention of re-infection of the

vermicularis Technique to identify pyrvinium pamoate, individual already infected,
eggs, eggs in stool stilbazium iodide, prevention of the infection by contact
pyrantel pamoate, for which mass treated of all infected
mebendazole cases may be required, along with
other hygienic measures.
Parasites Transmission Diseases Pathogenesis / Clinical Findings
Trihuris trichiura Oral – feacal route Trichiuriasis Abdominal pain, diarhhoea, anemia, acute
(eggs) appendicitis, rectal prolapse.
Wuchereria Female masquito Filariais, Massive edema of legs Elephantiasis
bancrofti Anopheles & Culex Elephantiasis, (adult worm inflame lymph nodes &
species) deposits Pulmonary obstruct lymph vessels), lymphaginitis,
larvae on the skin by eosinophilia. cellulitis, obstruction leads to edema &
biting. fibrosis of legs & genitalia(scrotum).
Pulmonary Esoniphila cause due to
microfilarae larvae in lung.
Loa loa Bite of the Deer Fly Loiasis No inflammatory response, but
(Mango Fly),which hypersensitive reaction cause transient,
deposits infective localized, non erythromatous
larvae on the skin subcutaneous edema (Calabar
sweeling).Also cause infection in
conjunctiva.
Onchocerca Human infected by Onchocerciasis Inflammation in subcutaneous tissues,
volvulus female blackfly, pruritis papules & nodules form in
infective form is larvae response to adult worm .Microfilariae
larvae cause lesion sin eye & lead to
blindness, Wrinkled skin (hanging groin),
in inguinal region, thickening, scaling,
dryness, itching on skin cause dermatitis
also called Lizard Skin.
Parasites Lab Diagnosis Treatment Prevention
Trihuris Typical eggs (barrel Mebendazole, Proper disposal of the night-soil,
trichiura shaped or lemon Pyrantal prevention of the consumption of
shaped) with a plug pamoate uncooked vegetables & fruits grown in
at each end in the native gardens.
stool.
Wuchereria Microfilariae Diethylcarbamazi Prevention involved mosquito control with
bancrofti reveals in blood ne (microfilarae) insectides and use of protective clothing,
smears. netting.

Loa loa Microfilariae Diethylcarbamazi Control of flyby insecticides.

reveals in blood ne . Worms in
smears. eye require
surgery.

Onchocercu Microfilariae Ivermectin Control of black fly with insecticides.

s volvulus reveals in blood agaisnt
smears. microfilariae but
not adults.
Suramin kills
adult but toxic in
eye disease
pateints.