Transcript Slide 1

Maria Immaculata Iwo
School of Pharmacy
ITB
1
INTRODUCTION
• Parasitic diseases continue to be a major public health
problem all over the world with associated high degree of
mortality, morbidity, and man-day loss.
• WHO statistics put parasites as leading cause of death after
HIV/AIDs and tuberculosis
• One out of ten living persons suffer from one or more of
seven major tropical diseases, of which five are parasitic in
nature.
• Out of 60 million deaths in world, more than 25% are
accounted to parasites.
• Parasites affect over half the world’s population and are a
major cause of mortality in the developing country.
2
• With increasing
–
–
–
–
–
–
–
population,
urbanization,
industrialization,
poor socio-economic conditions and
poor sanitation facilities in developing countries,
deforestation,
unplanned reforestation and climatic changes,
 some diseases which were previously
unrecognized, are emerging.
•
•
•
•
Ethnic eating habits,
poverty,
tourism to exotic areas and
environmental degradation
 have led to
emergence
of food-borne
3
parasitic infections
• Five parasitic infections
– Malaria
– Trypanosomiasis
– Leishmaniasis,
– Schistosomiasis
Presenting the greatest
challenges in the
developing country
– Filariasis
• A number of parasites are now world-wide in
their distribution
4
• Many infections once thought to be harmless,
are now known to be life-threatening in
immunocompromised individuals and those
suffering from acquired immunodeficiency
syndrome (AIDS).
These include:
– Toxoplasma gondii
– Cryptosporidium parvum
– Isospora belli
– Microsporidia
5
maria immaculata iwo, sf itb
• Currently no vaccine against any parasitic
infection, in human, is available
• Parasite also have capacity to develop drug
resistance
• Vectors transmitting certain parasitic infections
have developed insecticide resistance
Therefore, parasitic infections
present enormous challenges
6
maria immaculata iwo, sf itb
• This lecture will cover
– Essential details of general parasitology
– Description of various protozoa and helminths
• Geographical distribution
• Habitat
• Morphology
• Life cycle
• Pathogenicity, (and Immunity)
• Epidemiology
• Laboratory diagnosis,
• Treatment and prevention
– Description of various virus
7
maria immaculata iwo, sf itb
LITERATURE
1. Arora, D. R. and B. Arora, 2007, Medical
Parasitology, 2nd ed., CBS Publ. &
Distributor, New Dehli
2. Markell, E. K., M. Voge, and D. T. John, 1992,
Medical Parasitology, 7th ed., WB Saunders
Co., Philadelphia
3. Peters, W. & H. M. Gilles, A Colour Atlas of
Tropical Medicine & Parasitology, 3rd. ed.,
Wolfe Medical Publ. Ltd, Netherlands
maria immaculata iwo, sf itb
8
9
blood and Tissue
parasite
10
maria immaculata iwo, sf itb
11
12
13
14
Life cycle of Isospora belli
15
Replication of HIV
Binding
Reverse transcription
Fusion
Integration
Transcription
Endocytosis
Nuclear localization
Uncoating
Splicing
Lysosome
RNA export
Genomic RNA
Modification
mRNA
Assembly
Maturation
Budding
Translation
16
Lyfe cycle of DNA virus
1. Attachment
(Adsorption)
8. Budding from
nucleus and
release of virus
2. Penetration
(pinocytosis. etc)
7. Assembly of virus
particles in nucleus
6. Late translation of
viral mRNA into
structural proteins
Inhibition of viral
DNA polymerase:
Acyclovir,
Foscarnet
3. Uncoating and
Transfer of DNA
to nucleus
4. Early transcription
and translation of
viral mRNA
5. Synthesis of viral DNA
and late transcription
of viral mRNA
17
The objective of this lecture
Known the characteristic of parasitic infection is benefit
for…
 morphologic  specific, important for diagnoses
 life cycle  complex, need or need not other host,
more then one host,
 for completely elimination of the parasite
 Location  treatment strategic
E. histolytica: intestine (GIT), lung, liver, brain, etc
A. lumbricoides : GIT, lung, reproductive organ, brain,
Trypanomiasis  two biological stadium:
- haemolymphatic & meningoencephalitic
18
The objective of this lecture
 Clinical symptoms 
- similar to organ system clinical symptom?
- with or without clinical symptom
- can be acute or chronic infections
 harmful effect of parasitic infection
- pharmacologic and or immunologic effects
cause by a burden of parasite inside our body,
its existence (colic of Ascariasis, encephalitis of N. fowlery)
its stadia morphologic (eggs of Shistosome spp., sucker of
worm),
toxin secreted, toxic metabolite,
dead parasite (Filarial worm  Mazotti reaction, T. solium
blindness),
granulomma (E. histolytica);
Lymphoma, abortion (Toxoplasmosis)
19
 Treatment :
not only used antiparasitic drugs, but also
agent to cure clinical manifestations.
 Sanitation and hygienicity
Leuchorrhea  T. vaginalis
20
• Habits
 eating habits back to nature: eating raw
vegetables, undercooked meat, fish, rabbit,
insect time to suck the blood
Children  health education
 Health condition (Immunity)
 “healthy - clean” food
maria immaculata iwo, sf itb
21
maria immaculata iwo, sf itb
22
• Parasitology is the area of biology concerned
with the phenomenon of dependence of one
living organism on another.
• PARASITE
A parasite is an organism that is entirely
dependent on another organism, referred to
as its host, for all or part of its life cycle and
metabolic requirements.
It is of two types:
• Microparasite
• Macroparasite
maria immaculata iwo, sf itb
23
• Microparasite
It is small, unicellular and multiplies within its
vertebrate host, often inside cells.
Viruses, bacteria and protozoa are
microparasites.
• Macroparasite
It is large, multicellular and has no direct
reproduction within its vertebrate host.
This category includes helminths.
maria immaculata iwo, sf itb
24
On the basis of their location, parasites may
also be divided into two types:
• Ectoparasites
• Endoparasites
• Ectoparasites
Organisms which live on the surface of the skin or
temporarily invade the superficial tissues of the host
(e.g. lice).
The infection by these parasites is known
an infestation.
maria immaculata iwo, sf itb
25
• Endoparasites
 Organisms that live within the body of the host
All protozoan and helminthic parasites of man are
endoparasites.
The invasion by endoparasites is known as
infection.
maria immaculata iwo, sf itb
26
On the basis of host, parasites are subdivided into
the following types:
 Obligate parasites:
Organisms that cannot exist without a host
(e g. Taxoplasma gondii)
 Facultative parasites:
Organisms that under favourable circumstances
may live either a parasitic or free-living existence
(e.g. Naegleria fowleri, Acanthamoeba spp. and Balamuthia
mandrillaris).
maria immaculata iwo, sf itb
27
On the basis of host,
the following types:
parasites are subdivided into
 Obligate parasites:
Organisms that cannot exist without a host
(e g. Taxoplasma gondii)
 Facultative parasites:
Organisms that under favourable circumstances
may live either a parasitic or free-living existence
(e.g. Naegleria fowleri, Acanthamoeba spp.)
maria immaculata iwo, sf itb
28
 Accidental parasites:
Organisms that attack an unusual host
(e.g. Echinococcus granulosus in man).
 Aberrant parasites:
Organisms that attack a host where they cannot live
or develop further
(e.g. Toxocara canis in man).
 Free-living:
The term free-living describes the non-parasitic
stages of existence which are lived independently of
a host.
e.g. hookworms have active free-living stages in
the soil.
maria immaculata iwo, sf itb
29
HOST
• is defined as an organism which harbours the
parasite and provides the nourishment and
shelter to the latter.
 Definitive host
This is the host in which sexual reproduction
of the parasite takes place or in which the most
highly developed form of a parasite occurs.
When the most mature form is not obvious, the
definitive host is the mammalian host.
maria immaculata iwo, sf itb
30
 intermediate host
The host which alternates with the definitive host
and in which the larval or asexual stages of a parasite
are found.
Some parasites require two intermediate hosts for
completion of their life cycle
 Paratenic host
A host in which larval stage of a parasite survives but
does not develop further. It is often not a necessary
part of the life cycle.
 Reservoir host
A host which harbours the parasite and serves as an
important source of infection to other susceptible hosts.
Epidemiologically, reservoir host are important in the
control of parasitic diseases
31
Zoonosis
• This term is used to describe an animal infection that is
naturally transmissible to humams either directly or
indirectly via a vector.
Examples of parasitic diseases that are zoonosis include:
- Leishmaniasis,
- South American trypanosomiasis,
- rhodesiense trypanosomiasis.
- japonicum schistosomiasis,
- trichinosis, fascioliasis,
- hydatid disease, and cryptosporidiosis
maria immaculata iwo, sf itb
32
Vector
• A vector is an agent, usually an insect, that transmits an
infection from one human host to another.
• The term mechanical vector is used to describe a
vector which assists in the transfer of parasitic forms
between hosts but is not essential in the life cycle of the
parasite
e.g. a housefly that transfers amoebic cysts from
infected food that is eaten by humans.
maria immaculata iwo, sf itb
33
HOST-PARASTTE RELATIONSHIPS
• Symbiosis
An association in which both host and parasite are so
dependent upon each other that one can not live without
the help of the other.
• Commensalism
An association in which only parasite derives benefit
without causing any injury to the host.
• Parasitism
Parasitism is a relationship in which a parasite benefits
and the host provides the benefit. The host gets nothing
in return and always suffers from some injury.
The degree of dependence of a parasite on its host
varies
34
SOURCES OF INFECTION
Parasitic infections originate from following sources:
1. Contaminated soil and water;
Soil polluted with human excreta acts as a source
of infection with
- Ascaris lumbricoides,
- Trichuris trichiura,
- Ancylostoma duodenale,
- Necator americanus and
- Strongyloides stercoralis
Before acquiring infectivity for man, eggs of these
parasites undergo certain development in the soil.
 These are known as soil transmitted helminths
35
SOURCES OF INFECTION
• Water polluted
with human excreta may contain viable cysts of
– Entamoeba histolytica,
– Giardia lamblia,
– Balantidium coli,
eggs of
- Taenia solium,
- Hymenolepis nana,
and the infective cercarial stage of
- Schistosoma haematobium,
- S. mansoni
- S. japonicurn.
36
SOURCES OF INFECTION
2. Freshwater fishes
constitute the source of Diphylobothrium latum and
Clonorchis sinensis.
3. Crab and crayfishes
are the sources of Paragonimus westermani.
4. Raw or undercooked pork
is the source of Trichinella spiralis, T. solium,
Fasciola hepatica, T. saginata, and S. suihominis.
5. Raw or undercooked beef
is the source of T. saginata, Toxoplasma gondii, and
S. hominis.
37
SOURCES OF INFECTION
6. Watercress
is the source of Fasciola hepatica.
7. Blood-sucking insects
transmit Plasmodium spp., Wuchereria bancrofti,
Brugia malayi, Onchocerca volvulus, T. brucei, T. cruzi,
Leishmania spp. and Babesia spp.
8. Housefly (mechanical carrier)
is the source of E. histolytica.
9. Dog
is the source of Echinococcus granulosus and
Toxocara canis (visceral larva migrans).
38
SOURCES OF INFECTION
10. Cat
is the source of T. gondii,
11. Man
is the source of E. histolytica, Enterobius vermicularis,
and H. nana.
12. Autoinfection
may occur with E. vermicularis and S. stercoralis,
leading to hyperinfection,
maria immaculata iwo, sf itb
39
PORTAL OF ENTRY INTO THE BODY
1. Mouth
The commonest portal of entry of parasites is oral,
through contaminated food, water, soiled fingers or
fomites.
– This mode of transmission is referred to as faecal-oral
route.
– e.g.
•
•
•
•
•
E. histolytica,
G lamblia,
E. vermicularis,
T. trichiura,
T. spiralis,
T. solium,
D. latum,
F. hepatica,
Fasciolopsis buski,
B. coli.
A. lumbricoides,
T. saginata,
C. sinensis
P. westermani
maria immaculata iwo, sf itb
40
PORTAL OF ENTRY INTO THE BODY
2. Skin
• Infection with A. duodenale, N. americanus and S.
stercolaris is acquired when filariform larvae of these
nematodes penetrate the unbroken skin of an individual
walking over faecally contaminated soil.
• Schistosomiasis caused by S. haematabium, S. mansoni
and S. japonicum is acquired when the cercarial larvae,
in water, penetrate the skin.
• A large number of parasites e.g, Plasmodium spp., W.
bancrofti, B. malayi, O. volvulus, T. brucei, T. cruzi,
Leishmania spp. and Babesia spp. are introduced
percutaneoursly when blood-sucking arthropods
puncture the skin lo feed.
41
PORTAL OF ENTRY INTO THE BODY
3. Sexual contact
Trichomonas vaginalis is transmitted by sexual contact,
E. histolytica and G. lamblia may also be transmitted by
anal-oral sexual practices among male homosexual
4. Kissing
E. gingivalis is transmitted from person-to-person by
kissing or from contaminated drinking utensils.
5. Congenital
Infection with T. gondii and Plasmotiium spp. may be
transmitted from mother to foetus transplacentally
maria immaculata iwo, sf itb
42
PORTAL OF ENTRY INTO THE BODY
6. Inhalation
Airborne eggs of E. vermicularis may be inhaled into
posterior pharynx leading to infection.
7. latrogenic infection
- Malaria parasites  transmitted by transfusion of
blood from the donor with malaria containing
asexual forms of erythrocytic schizogony  This is
known as trophozoite-induced malaria or transfusion
malaria.
- Malaria parasites may also be transmitted by the use of
contaminated syringes and needles  This may
occur in drug addicts.
43
LIFE CYCLE OF HUMAN PARASITES
• On the basis of their life cycles human parasites can he
divided into three major groups:
NO INTERMEDIATE HOST
Protozoa
Helminths
 Entamoeba histolytica
 G. lamblia
 Chilomastix mesnili
 T. vaginalis
 B. coli
 E.
vermicularis
 T. trichiura
 Ascaris lumbricoides
 A. duodenale
 N. americanus
 H. nana
44
ONE INTERMEDIATE HOST
INTERMEDIATE
HOST
PARASITE
INTERMEDIATE
HOST
PARASITE
pig
T. solium
T. spiralis
Mosquito
W. bancrofti
B. malayi
Cow
T saginata
Snail
Schistosoma spp.
Man
E. granulosus
Plasmodium spp.
Copepod
D. medinensis
Flea
H. nana
Fly: - Sandfly
- Tsetse
- Chrysops
- Simulium
Leishmania
Trypanosoma spp.
Loa loa
O. volvulus
Triatomine bug
T. cruzi
45
TWO INTERMEDIATE HOSTS
INTERMEDIATE
HOSTS
PARASITE
Snail, crustacean
Paragonimus westermani
Cyclops, fish
Diphyllobothrium latum
Snail, fish
Clonorchis sinensis
Snail, plant
Fasciola spp.
maria immaculata iwo, sf itb
46
PATHOGENICITY
• A parasite may live in or on the tissues of its host
- without causing evident harm.
- However, in majority of cases the parasite has the
capacity to produce damage.
• With the advent of AIDS, there is an increase in the
incidence of newer parasitic infections caused by
Cryptosporidium parvum, Isospora belli, and other
hitherto unheard of parasites.
– These parasites also cause infections in patients who are
immunocompromised
e.g, patients receiving cytotoxic drugs or organ transplant.
maria immaculata iwo, sf itb
47
Damage may be produced by the parasites
1. Traumatic damage
 Relatively slight physical damage is produced by entry of
- filariform larvae of S. stercoralis, A. duodenale and N.
americanus and
- cercarial larvae of the Schistosoma spp. into the skin.
 Migration of several helminthic larvae through the lung
produces traumatic damage of pulmonary
capillaries leading to extravasation of blood into the lung.
 Similar damage in cerebral, retinal or renal capillaries may
lead to serious injury.
 Eggs of S haematobium and S. mansoni cause extensive
damage with haemorrhage as they escape from vesicle and
mesenteric venules, respectively, into the lumen of the
urinary bladder and the intestinal canal
48
 Attachment of hookworms (A. duodenale and N.
americanus to the intestinal wall results in traumatic
damage of the villi and oozing of blood at the site of
attachment
 Large worms, such as A. lumbricoides and T. saginata
may produce intestinal obstruction.
 Ascaris, in addition, may occlude lumen of the appendix
or common bile duct, may cause perforation of the
intestinal wall, or may penetrate into the parenchyma of
the liver and the lungs.
2. Lytic necrosis

E. histolytica secretes lytic enzyme which lyses tissues for
its nutritional needs and helps it to penetrate into the
tissue of the colon and extraintestinal viscera.
 Obligate intracellular parasites e.g. Plasmodium spp.,
Leishmania spp., Trypanosoma cruzi and T. gondii cause
necrosis of parasitized host cells during their growth and
multiplication
49
3. Inflammatory reaction
– Most of the parasites provoke cellular proliferation and
infiltration at the site of their location.
– In many instances the host reaction walls off the parasite
by fibrous encapsulation.
– In metazoan and in some protozoan parasitoses, there is a
moderate-to-notable eosinophilia.
– Iron-deficiency, pernicious and haemolytic anaemia
develop in patients with hookworm disease,
diphyllobothriasis and malaria, particularly blackwater
fever, respectively.
– E. histolytica may produce inflammation of the large
intestine leading to the formation of amoebic granuloma or
amoeboma.
– Parasitization of fixed macrophages in the spleen, bone
marrow, and lymph nodes by L. donovani causes
proliferation of reticuloendothelial cells.
50
4. Competition for specific nutrients
Diphyliohothrium latum competes with the host for vitamin
B12 leading to parasite-induced pernicious anaemia.
5. Allergic manifestations
 the normal secretions and excretions of the growing
larvae of some helminthes and the products liberated
from dead parasites may give rise to various allergic
manifestations
e.g,
• Schistosomes cause cercarial dermatitis and eosinophilia
• D. medinensis and T. spiralis infections
cause urticaria and eosinophillia,
• rupture of hydatid cyst may precipitate anaphylaxis.
maria immaculata iwo, sf itb
51
6. Neoplasia
– Clonorchis sinensis and Opisthorchis viverrini have
been associated with cholangiocarcinoma
– S. haematobiumn with vesical carcinoma
– E. histolytica with sigmoid granuloma / amoeboma.
7. Secondary Infection
– Strongyloidiasis, trichinosis and ascariasis, the
migrating larvae may carry bacteria and viruses from
the intestine to the blood and tissues leading to
secondary infection.
– Leismaniasis Pasca Kala Azar
52
IMMUNITY IN PARASITIC INFECTIONS
Because of their biochemical and structural complexity,
protozoa and helminths present a large number of
antigens to their hosts.
• Protozoa (micro parasites) are small and multiply
within their vertebrate host, often inside the cells.
– Thus posing an immediate threat unless contained by an
appropriate immune response.
• Helminths (macroparasites) are large and do not
multiply within their vertebrate host.
– Thus they do not present an immediate threat after initial
infection.
• Therefore, immune responses to protozoa and
helminths are different from one another.
53
Immunological protection against parasite infections is
much less efficient than it is against bacterial and
virus infections. This is due t o the following factors:
1. As compared to bacteria and viruses, parasites are large and
more complex structurally and antigenically so that
immune system may not be able to mount immune
response against the protective antigens.
2. Many protozoan parasites (e.g. Leishmania spp. and T.
gondii) are intracellular.
This protects them from immunological attack.
3. Many parasites, both protozoa and helminths, live inside the
intestines.
This location limits the efficiency of immunological attack
and also facilities dispersal of the infective forms of the
parasites.
54
4. T. brucei gambiense and T. b. rhodesiense exhibit
antigenic variations within the host.
 When antibody response to one antigenic type
reaches peak, antigenic variation of the parasite
occurs by mutation.
The new antigenic type is unaffected by the antibodies
against the parent strain.
  This enables the prolonged persistence of the
parasite in the host.
5. Many nematodes have a cuticle which is antigenically
inert and evokes little immune response.
6. L donovani causes extensive damage to the RES
(reticuloendothelial system) thus leading to
immunological tolerance.
55
7. Enterobius vermicularis does not breach the integrity of
gut wall, thus immune system is not stimulated.
8. In most of the parasitic infections, immunity lasts only till
original infection remains active.
This is known as concomitant immunity (previously
called premunition or infection-immunity).
A possible exception is cutaneous leishmaniasis in
which the ulcer heals leaving behind good protection
against reinfection.
maria immaculata iwo, sf itb
56
The protective immune response to parasitic infections has
four arms:
 Cytotoxic T (Tc) cells.
Constituting cell-mediated
 Natural killer (NK) cells.
immunity
 Activated macrophages.
 Antibody (produced by B-cells)
Constituting humoral
immunity
The main classes of antibody produced are
– IgM  the first appear, mark the presence of acute infection
– IgG  usually the most abundent type in parasitic infections
– IgE  Helminths and ectoparasites also provoke high
titres of IgE antibodies
57
LABORATORY DIAGNOSIS
• Laboratory diagnosis of parasitic infections can
be carried out by
* Demonstration of parasite
* Immunodiagnosis
* Molecular biological methods
maria immaculata iwo, sf itb
58
 Demonstration of parasite
CLINICAL
SPECIMEN
PARASITES
Blood
 Plasmodium spp., Babesia spp. inside the RBCs
Stool
Cysts/trophozoites:
E. histolytica, G. lamblia, B. coli, I. belli
Eggs: Many worms
Larvae: T. spiralis, S. stercoralis
Adult worms: Taenia spp., A. lumbricoides,
T. spiralis, E. vermicularis, hookworms
 L. donovani inside monocytes
 Trypomastigotes of T. b. gambiense,
T.b.rhodesiense and T. cruzi and microfilaria of
W. bancrofti and B. malayi in the blood
59
CLINICAL
SPECIMEN
PARASITES
Urine
Eggs of S. haematobium
Trophozoites of T. vaginalis
In the case of Chyluria cause by W.bancrofti,
microfilaria in chyluria urine.
Genital
specimens
Trophozoites of T. vaginalis may be demonstrated
in the vaginal and urethral discharge and in the
prostatic secretions
Ceresbrospinal Trypomastigotes of T. b. gambiense and
T.b.rhodesiense;
fluid (CSF)
Trophozoites of N. fowleri, Acanthamoeba spp.,
Sputum
Eggs of P. westermani
Rarely migrating larvae of A. lumbricoides, S.
stercoralis, A. duodenale, N. americanus
60
Trophozoites of E. histolytica
CLINICAL
SPECIMEN
PARASITES
Tissue biopsy
and aspiration
1. Scolices and brood capsule in the fluid aspirate of
Hydatid cyst
2. Amastigot L. donovani  inside RES in the aspirate
of spleen, bone marrow, liver, and lymph nodes.
3. Larvae of T. spiralis, T solium  in muscle biopsy
4. Trophozoites of G. lamblia  duodenum aspirate
5. Trophozoites of E.histolytica  in pus aspirated from
amoebic liver abcess and in necrotic tissue obtained
from the based of the ulcers in the large intestine.
Culture
Culture of parasites is particularly useful when the
number of parasites in the specimens is too small.
Animal
Inoculation
It is useful in the detection of T. gondii and Babesia
spp. in the clinical specimens.
61
 Immunodiagnosis
two types:
 Skin tests
 Serological tests.
maria immaculata iwo, sf itb
62
• Skin tests
These tests are performed by intradermal injection of
parasitic antigens and are read as under:
1. Immediate hyperensitivity reaction:
It reveals erythema and induration after 30 minutes
of injection.
This reaction is seen in cases of hydatid disease,
filariasis, schistosomiasis ascariasis, and
strongyloidiasis
2. Delayed hypersensitivity reaction:
It reveals erythema and induration after 48 hours of
injection.
This reaction is seen in cases of leishmaniasis,
trypanosomiasis, toxoplasmosis and amoebiasis,
maria immaculata iwo, sf itb
63
• Serological test
These tests detect antibodies or antigens in the patient
serum and other clinical specimens
TEST
ELISA and RIA
Indirect
haemagglutination test
Indirect
fluorescent
antibody test
APPLICATION
Toxoplasmosis, toxocariasis, leishmaniasis,
Chagas’ diseases, malarla and
schistosomiasis
Amoebiasis, hydatid disease, filariasis,
cysticercosis, strongyloidiasis.
Amoebiasis, malaria, toxoplasmosis and
schistosomiasis
64
TEST
APPLICATION
Complement
fixation test
Paragonimiasis, Chagas' disease and
leishmaniasis
Agglutination tests:
• Direct
agglutination
Visceral leishmaniasis
 Bentonite
Trichinelosis and hydatid disease,
flocculation
maria immaculata iwo, sf itb
65
 Molecular biological methods
These include DNA probes and polymerase chain reaction
(PCR).
1. DNA probes
 DNA probe is a radio labelled or chromogenically labelled
piece of single- stranded DNA complementary to a
segment of parasitic genome and unique to a particular
parasitic strain, species and genus.
 Specific probe is added to the clinical specimen.
 If the specimen contains the parasitic DNA, probe will
hybridize with it which can be detected.
 DNA probes are available for the detection of the infection
with P. falciparum, W. Bancrofti,
T. b. gambiense, T. b. rhodesiense, T. cruzi
Onchocerca spp.
66
2. Polymerase chain reaction (POP)
– PCR is a DNA amplification system that allows
molecular biologist to produce microgram quantities
of DNA from picogram amounts of sorting material.
– It has been employed to detect faecal antigens for the
diagnosis of intestinal amoebiasis, giardiasis and
other intestinal parasitic infections.
maria immaculata iwo, sf itb
67
Community Participation
Drugs:
- Chemotherapy
- Chemoprophylaxis
Method of
controlling
Parasitic diseases
Health education
of population
at risk
Vector control
- Insecticides,
- molluscicides,
- Land development
- Drainage,
- Bush clearance
Reservoir host control
- Destruction of animal hosts
- Drug treatment of human
hosts
68