parasitology.ppt

7/23/2019 parasitology.ppt

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Human ParasitologyHuman Parasitology

Shandong UniversityShandong University

Department of ParasitologyDepartment of Parasitology

He ShenyiHe Shenyi（何深一）（何深一）

MD, Ph.D. ProfessorMD, Ph.D. Professor





Introduction to HumanIntroduction to Human

ParasitologyParasitology

Concept of Human ParasitologyConcept of Human Parasitology

The Scope of Human ParasitologyThe Scope of Human Parasitology

Terms of ParasitologyTerms of Parasitology

Parasites’Parasites’ Harms to ManHarms to Man

Human mmunity against ParasitesHuman mmunity against Parasites

CharacteristicsCharacteristics of parasitic diseasesof parasitic diseases



Human parasitologyHuman parasitology

Human parasitology is the study of thoseHuman parasitology is the study of those

organisms !hich parasitise humans. "ccordingorganisms !hich parasitise humans. "ccording

to the very #road definition of parasitology,to the very #road definition of parasitology,parasites should include the viruses, #acteria,parasites should include the viruses, #acteria,

fungi, proto$oa and meta$oa %multi&celledfungi, proto$oa and meta$oa %multi&celled

organisms' !hich infect their host species.organisms' !hich infect their host species.

Ho!ever, for historical reasons the first threeHo!ever, for historical reasons the first three

have #een incorporated into the discipline ofhave #een incorporated into the discipline of

Micro#iology.Micro#iology.



2. The Scope of Human Parasitology2. The Scope of Human Parasitology

Parasitology claims those proto$oa %single celled animals',Parasitology claims those proto$oa %single celled animals',

helminths %!orms' and arthropods !hose e(istence dependshelminths %!orms' and arthropods !hose e(istence depends

on the availa#ility of host animals t is also possi#le to argueon the availa#ility of host animals t is also possi#le to argue

a#out !hether certain insects and mites are )temporarya#out !hether certain insects and mites are )temporary

parasites) or )micro&predators), insects as a group #elong toparasites) or )micro&predators), insects as a group #elong to

the discipline of *ntomology, !hile tic+s and mites are thethe discipline of *ntomology, !hile tic+s and mites are the

concern of "carology. The insects that are of most interest inconcern of "carology. The insects that are of most interest in

human parasitology are those that are vectors of severalhuman parasitology are those that are vectors of several

parasitic infectionsparasitic infections.



H um

an P

ar a si t

ol

o g y

Medical

Helminthology

Medical

Protozoology

Medical

Arthropodology

•

Class Nematoda• Class Trematoda

• Class Cestoda

• Class MetacanthocephalaClass Metacanthocephala

• Class Lobosea

• Class oomastigophorea• Class Sporo!oa

• Class Ciliophora

• Class "nsecta• Class #rachnida

• Class Crustacea

• Class Chilopoda





Class ZoomastigophoreaClass Zoomastigophorea

Leishmania sp

Trichomonas vaginalisGiardiaGiardia



Class SporozoaClass Sporozoa

Plasmodium spp

Toxopasma gondiiCryptosporidium

Pneumocycstis carinii



Class CiliophoraClass Ciliophora

– Balantidium coli





Class NematodaClass Nematoda

Ascaris

lumbricoides

Trichuris trichiura

Hookworm Enterobius vermicularis

Filaria

Trichinella spiralis



NematodaNematoda



Class TrematodaClass Trematoda

Clonorchis sinensis

Fasciolopsis buski

Paragonimus westermani Schistosoma japonicum



TrematodaTrematoda



Class CestodaClass Cestoda

Taenia solium

Taenia saginata

*chinococcus granulosus



CestodaCestoda



ClassClass MetacanthocephalaMetacanthocephala

Macracanthorhynchus

hirudinaceus



Class InsectaClass Insecta

Anopheles sinensis Lucilia sericata

-ice

Sandflies , leas





Class ArachnidaClass Arachnida

Sarcopes scabiei

follicle mite

Ticks; Mites



Class CrustaceaClass Crustacea

Cambaroides

Potamon



Class ChilopodaClass Chilopoda

centipede



4. Terms o Parasitology4. Terms o Parasitology



SymbiosisSymbiosis

%/'Sym#iosis%/'Sym#iosis （共同生活）（共同生活） T!oT!o

different organisms live together anddifferent organisms live together and

interact, in this association oneinteract, in this association one

partner lives in or on another one’spartner lives in or on another one’s

#ody. including 0 types1Mutualism,#ody. including 0 types1Mutualism,

Commensalism, Parasitism.Commensalism, Parasitism.



2%3'Mutualism%2%3'Mutualism% 互利共生）互利共生） is ais apermanent association #et!een t!opermanent association #et!een t!o

different organisms that life apart isdifferent organisms that life apart is

impossi#le, t!o partners #enefit eachimpossi#le, t!o partners #enefit eachother, such as termites and flagellates.other, such as termites and flagellates.

The mutuals are meta#olicallyThe mutuals are meta#olically

dependent on one another4 one cannotdependent on one another4 one cannot

survive in the a#sence of the other.survive in the a#sence of the other.

SymbiosisSymbiosis





%0'%0' CommensalismCommensalism （片利共生或共栖）（片利共生或共栖） is theis the

association of t!o different organisms, inassociation of t!o different organisms, in

!hich one partner is #enefited !hile the!hich one partner is #enefited !hile the

other neither #enefited nor in5ured, such asother neither #enefited nor in5ured, such as*. coli and man.*. coli and man.

%6' Parasitism%6' Parasitism （寄生关系）（寄生关系） is the associationis the association

of t!o different organisms, in !hich oneof t!o different organisms, in !hich onepartner is #enefited !hile the other ispartner is #enefited !hile the other is

in5ured, such as "scaris lum#ricoides andin5ured, such as "scaris lum#ricoides and

man.man.

SymbiosisSymbiosis



ParasiteParasite

%7' Parasite%7' Parasite （寄生虫）（寄生虫） nn

parasitism, it is the #enefitedparasitism, it is the #enefited

partner. t is an animal organismpartner. t is an animal organism

!hich lives in or on the host in order!hich lives in or on the host in order

to o#tain nourishment and shelterto o#tain nourishment and shelter

from the host as !ell as does harmsfrom the host as !ell as does harms

to the host.to the host.



ParasiteParasite

endoparasiteendoparasite

ectoparasiteectoparasite

temporary parasitetemporary parasite

permanent parasitepermanent parasite

o#ligatory parasiteo#ligatory parasite

facultative parasitefacultative parasite

accidental parasiteaccidental parasite

opportunistic parasiteopportunistic parasite



EndoparasiteEndoparasite



*ctoparasite*ctoparasite



HostHost

%8' Host%8' Host

（宿主）（宿主） n parasitism, it suppliesn parasitism, it supplies

the parasite !ith nourishment and shelter,the parasite !ith nourishment and shelter,

it is the in5ured partner.it is the in5ured partner.

%9' Carrier%9' Carrier （带虫者）

（带虫者） " person !ho" person !ho

har#ours parasite has no clinicalhar#ours parasite has no clinicalsymptoms, is an important source ofsymptoms, is an important source of

infection in epidemiology.infection in epidemiology.



%:' Definitive %final' host%:' Definitive %final' host （终宿（终宿主）主） har#ours adult or se(uallyhar#ours adult or se(ually

reproductive stage of a parasite.reproductive stage of a parasite.

%;' ntermediate host%;' ntermediate host （中间宿（中间宿

主）主） har#ours larval or ase(uallyhar#ours larval or ase(uallyreprodctive stage of a parasite,reprodctive stage of a parasite,

according to priority they are classifiedaccording to priority they are classified

into first intermediate host, secondinto first intermediate host, secondintermediate host, third intermediateintermediate host, third intermediate

host.host.



%/<' =eservoir hosts%/<' =eservoir hosts （保虫宿主）（保虫宿主）are the verte#rate hosts !hichare the verte#rate hosts !hich

har#our the same species of parasitehar#our the same species of parasite

at same stage as a human host. Theyat same stage as a human host. They

are an important source of infectionare an important source of infection

in epidemiology.in epidemiology.



ZoonosisZoonosis

%//' >oonosis%//' >oonosis （人兽共患病）（人兽共患病） refersrefers

to animal’s diseases !hich can #eto animal’s diseases !hich can #e

transmitted to man. %These animalstransmitted to man. %These animals

infected !ith parasites are calledinfected !ith parasites are called

reservoir hosts.'reservoir hosts.'



%/3' Paratenic host or transport%/3' Paratenic host or transport

hosthost （转宿主）（转宿主） is an a#normalis an a#normal

host in !hich some parasitic larvaehost in !hich some parasitic larvae

can survive #ut can’t develop intocan survive #ut can’t develop into

adults. f the larvae have a chance toadults. f the larvae have a chance to

enter their appropriate hosts, they canenter their appropriate hosts, they can

continue to develop into adults there.continue to develop into adults there.



(13)(13) -arva migrans-arva migrans （!虫"#$）（!虫"#$）means that the larvae living in theirmeans that the larvae living in their

a#normal hosts in !hich they cana#normal hosts in !hich they cannot gro! into adults #ut can !andernot gro! into adults #ut can !ander

every!here and cause the local andevery!here and cause the local and

systemic pathological lesions of thesystemic pathological lesions of thehosts.hosts.



Life cycleLife cycle

%/6'%/6' -ife cycle-ife cycle

（生活%）

（生活%） is the process ofis the process of

a parasite’s gro!th, development anda parasite’s gro!th, development and

reproduction, !hich proceeds in one orreproduction, !hich proceeds in one or

more different hosts depending on themore different hosts depending on thespecies of parasites.species of parasites.

%/7'nfective Stage%/7'nfective Stage （ & ' ( ）（ & ' ( ） is a stageis a stage

!hen a parasite can invade human #ody!hen a parasite can invade human #ody

and live in it .and live in it .




(16)(16) nfective =outenfective =oute （ & ' ) * ）（ & ' ) * ） is theis the

specific entrance through !hich thespecific entrance through !hich the

parasite invades the human #ody.parasite invades the human #ody.

(17)(17) nfective Modenfective Mode

（&'+,）（&'+,） meansmeans

ho! the parasite invades human #ody,ho! the parasite invades human #ody,

such as the cercariae of the #lood flu+esuch as the cercariae of the #lood flu+e

actively penetrate the s+in of a s!immingactively penetrate the s+in of a s!imming

man and the infective ascaris eggs areman and the infective ascaris eggs are

s!allo!ed #y man.s!allo!ed #y man.




%/:' "lternation of ?eneration1%/:' "lternation of ?eneration1

n life cycles of some parasites, theren life cycles of some parasites, there

are the regular alternations of se(ualare the regular alternations of se(ualand ase(ual reproductions , thisand ase(ual reproductions , this

phenomenon is called alternation ofphenomenon is called alternation of

generation, such as the life cycle ofgeneration, such as the life cycle ofPlasmodium viva(Plasmodium viva(..



%/;'%/;' Mechanical Transmission1Mechanical Transmission1

"rthropods play a role of the"rthropods play a role of the

transportation of pathogens, !hichtransportation of pathogens, !hichis not indispensa#le for the diseaseis not indispensa#le for the disease

transmission, such as flies carrytransmission, such as flies carry

typhoid #acilli, ascarid eggs andtyphoid #acilli, ascarid eggs and

amoe#ic cysts.amoe#ic cysts.



%3<' @iological Transmission1 Pathogens have to%3<' @iological Transmission1 Pathogens have to

spend a part of their life cycle in the vectorspend a part of their life cycle in the vector

arthropods in !hich they multiply or developarthropods in !hich they multiply or develop

into the infective stage and then invade theinto the infective stage and then invade the

human #ody under the help of the arthropod,human #ody under the help of the arthropod,

such as "nopheles mosAuitoes transmitsuch as "nopheles mosAuitoes transmit

malariamalaria..



$%olution of Parasitism

%olution of Parasitism

endoparasite ree living

ectoparasite Commensalism （片利共生）

temporary parasite Sym#iosis Mutualism （互利共生）

permanent parasite Parasitismo#ligatory parasite carrier

facultative parasite parasite Host

accidental parasite Patient

opportunistic parasite

inal host ntermediate host =eservoir host Paratenic host

>oonosis -arva migrans



&. Parasites' Harms to Man&. Parasites' Harms to Man

Mechanical effectsMechanical effects of parasites on host tissuesof parasites on host tissues

and organs1 e. g. , #iliary ascariasis and larvaand organs1 e. g. , #iliary ascariasis and larva

migrans.migrans.

Depriving nourishmentDepriving nourishment from hosts1 e.g.from hosts1 e.g.

hoo+!orms suc+ #lood.hoo+!orms suc+ #lood.

To(ic effect1To(ic effect1 e. g., mosAuitoes, spiders and tic+se. g., mosAuitoes, spiders and tic+s

introduce venom !hen they insert their mouth partsintroduce venom !hen they insert their mouth parts

into the s+in.into the s+in. mmuno&pathological lesionmmuno&pathological lesion e.g. schistosomae.g. schistosoma

liver cirrhosis4 !hen hydatid fluid is released from theliver cirrhosis4 !hen hydatid fluid is released from the

rupture of a hydatid cyst anaphyla(is often results.rupture of a hydatid cyst anaphyla(is often results.



( Human "mmunity against Parasites

Human "mmunity against Parasites

ts intensity and specificity are usually at a lo!er levelts intensity and specificity are usually at a lo!er levelthan those produced #y #acteria and viruses. t refersthan those produced #y #acteria and viruses. t refers

to on&sterili$ing immunity %Premunitionto on&sterili$ing immunity %Premunition 带虫 - .带虫 - .// Concomitant immunityConcomitant immunity 01-.01-. '. The host may'. The host may

#e protected from superinfection#e protected from superinfection 23&'23&' as long asas long asthe parasites remain in the #ody. This situation isthe parasites remain in the #ody. This situation is

+no!n as premunition%+no!n as premunition% 带虫 - .带虫 - . '. This may #e of'. This may #e of

great importance in endemic areas in limiting thegreat importance in endemic areas in limiting the

severity of infection !ith Plasmodium, Schistosome ,severity of infection !ith Plasmodium, Schistosome ,

hoo+!orms and other parasites.hoo+!orms and other parasites.



!"H#$ % Priority &iseases!"H#$ % Priority &iseases

/. Schistosomiasis/. Schistosomiasis

3. Malaria3. Malaria

0. ilariasis0. ilariasis

6. Trypanosomiasis6. Trypanosomiasis

7. -eishmaniasis7. -eishmaniasis

8. -eprosy %replaced #y HB"DS'8. -eprosy %replaced #y HB"DS'



hy !ere they selectedEhy !ere they selectedE

Schistosomiasis & 3<<,<<<,<<< infectedSchistosomiasis & 3<<,<<<,<<< infected

7<<,<<<&/,<<<,<<< deathsyear7<<,<<<&/,<<<,<<< deathsyear

Malaria & 7<<,<<<,<<< infectedMalaria & 7<<,<<<,<<< infected

3,7<<,<<< deathsyear3,7<<,<<< deathsyear

ilariasis & 37<,<<<,<<< infectedilariasis & 37<,<<<,<<< infected

Trypanosomiasis & 37,<<<,<<< infectedTrypanosomiasis & 37,<<<,<<< infected

87,<<< deathsyear87,<<< deathsyear

-eishmaniasis & /,3<<,<<< infected-eishmaniasis & /,3<<,<<< infected -eprosy & /,0<<,<<< infected-eprosy & /,0<<,<<< infected

"ppro(imately 37F of !orldGs population infected #y one"ppro(imately 37F of !orldGs population infected #y one

of these.of these.



General CharacteristicsGeneral Characteristics

/. Chronic diseases/. Chronic diseases

3. o effective vaccine3. o effective vaccine0. o practical chemotherapy0. o practical chemotherapy

6. "ffect young6. "ffect young

7. "ffect underprivileged7. "ffect underprivileged8. Bector&#orne8. Bector&#orne



?eographic Distri#ution?eographic Distri#ution

actors %*ndemicity'1actors %*ndemicity'1

/. Presence of a suita#le host/. Presence of a suita#le host

3. Ha#its of the host3. Ha#its of the host

0. *scape from the host0. *scape from the host

6. avora#le conditions outside of host6. avora#le conditions outside of host

7. *conomic and social conditions7. *conomic and social conditions

P f Di iP f Di i



Presence of Diseases in aPresence of Diseases in a

Population %Prevalence'1Population %Prevalence'1

actors reAuired1actors reAuired1

/. Source/. Source

infected personsinfected persons

carrierscarriers

animalsanimals

P f Di iP f Di i



Presence of Diseases in aPresence of Diseases in a

Population %Prevalence'1Population %Prevalence'1

3. Mode of transmission3. Mode of transmission

directdirect

indirectindirect

vectorsvectors

0. Suscepti#le host0. Suscepti#le host

immunityimmunity



Three +ey lin+s of disease transmissionThree +ey lin+s of disease transmission

/.Source of infection 3. =oute of transmission 0. Suscepti#le people/.Source of infection 3. =oute of transmission 0. Suscepti#le people

e(crement mouthe(crement mouth

secretion food, !ater, finger s+in or !oundsecretion food, !ater, finger s+in or !ound

#lood direct or indirect contact mucosa#lood direct or indirect contact mucosafocus of placentafocus of placenta

infection #lood transfusion, in5ection,infection #lood transfusion, in5ection,

intermediate host,intermediate host,

insects suc+ing #lood,insects suc+ing #lood,

congenital ,congenital ,

touch soil, !ater, grasstouch soil, !ater, grass



Diagnosis of ParasiticDiagnosis of Parasitic

nfections1nfections1

/. Clinical diagnosis/. Clinical diagnosis

3. -a#oratory diagnosis3. -a#oratory diagnosis



Treatment of ParasiticTreatment of Parasitic

nfections1nfections1

/. Medical and surgical/. Medical and surgical

3. Chemotherapy3. Chemotherapy

0. "deAuate nutrition0. "deAuate nutrition



Prevention and Control1Prevention and Control1

/. =eduction in sources/. =eduction in sources

3. *ducation3. *ducation

0. Destruction andor control of reservoir0. Destruction andor control of reservoir

hosts and vectorhosts and vector

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parasitology.ppt