MEDICAL PARASITOLOGY

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MEDICAL PARASITOLOGY
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• ??????(Medical parasitology) Medical
  parasitology,the study of animality
  pathogen?????? harming human health, is one of
  basic science of preventive medicine and clinical
  medicine. It studies the pathogenic parasites???
  and their relationships to the hosts?? and
  environment. it consists of medical
  protozoology?????, medical helminthology????? and
  medical entomology???????.

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A large mass of Ascaris lumbricoides that was
passed from the intestinal tract.  The ruler at
the bottom of the image is 4 cm (about 1.5
inches) in length.
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S.japonicum


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WHO???????????

• malaria (??)
• schistosomiasis (????)
• filariasis (???)
• leishmaniasis (????)
• trypanosomiasis (???)

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????(??)

• Malaria lt30?
• Schistosomiasis ?70?(03?100?)
• Filariasis ?????
• Leishmaniasis 300400?/?
• Hookworm disease2??(3930?)

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??????????

• 1.?5??????????(80),????60(????????)
• 2.????????????????,???75(??????)
• 3.??????????????
• 4.???????????
• 5.??????????????

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??????(Parasitism)

• (?)?? (symbiosis)
• Any organism that spends a portion or all of
  its life intimately associated with another
  living organism of a different species is known
  as symbiont ???, and the relationship is
  designated as symbiosis.
• ????????????,????????????????????

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1.??(commensalism)

• Commensalism????denotes an association that is
  beneficial to one partner and the neither
  benefited nor damaged to the other.
• (? ??????)

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2.????(mutualism)

• Mutualism???? is seen when such associations
  are beneficial to both organisms.
• (?? ????)

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3.??(parasitism)

• Parasitism????is a symbiotic relationship in
  which one animal, the host??, is to degree
  injured through the activities of the other, the
  parasite???.Parasite usually is the smaller of
  the two organisms.
• (?? ?)

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Parasite

• Obligate parasite
• An organism that cannot survive in any other
  manner is called an obligate parasite(?????).
• Facultative parasite
• Facultative parasite(?????) is an organism that
  may exist in a free-living state or as a
  commensal and that, if opportunity presents
  itself, may become parasitic.
• It is implicit in this term that the organism
  does not of necessity have to be a parasite at
  any stage of its existence.

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• Temporary parasite
• Temporary parasite are obligatory parasites at
  one or more stages of their life cycles but free
  living at others.
• Endoparasites and ectoparasites
• Parasites living within the host may be described
  as endoparasites, whereas those that are found on
  the surface of the body are called ectoparasites.

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• opportunistic parasite
• (????????) ??????????????????????,??????????,??
  ????????????????????(???)

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(?)Adaptations to Parasitism(???????????)

• Morphologic adaptations
• Apicomplexa and Microspora protozoa have no
  locomotor organelles.
• A digestive tract, is reduced in the trematodes
  and is absent in the cestodes.
• The reproductive system is very highly developed
  in the trematodes and cestodes.
• Specialized attachment organs have been developed
  by the flatworms.
• Many of parasites are much larger than their
  free-living relatives.

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• Biochemical changes
• Develop specialized mechanisms for effecting
  entrance into the body or tissue.
• Successfully overcome the immune response of the
  host
• Locate in relatively protected sites
• Changes in the parasite surface antigenic
  structure
• Modify the host immune response by products of
  parasite metabolism
• Increase reproductive capacity

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• (?)host
• Definitive host(???)
• The host in which sexual reproduction occurs is
  called the definitive host.
• Intermediate host(????)
• The specie in which larval develop is called
  intermediated host.

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• Reservoir host(????/????)
• Reservoir host is an animal which harbors
  parasites in nature and acts as a source of
  infection.
• Paratenic host(????)
• A host which acts as a transporting agent for
  the parasite and in which the parasite does not
  undergo any development is called paratenic host.

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• ?? life cycle(??? )
• The parasitic life cycle is the obligatory of
  parasites for their growth, development and
  multiplication that may be accomplished in their
  host (or hosts) or environment.
• ?????????????
• ????????????

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• Migration and
• localization
• (pathogenicity
• treatment and diagnosis) Stool
• Urine Mouth
  Bronchial
• Contact Secretion
• Vector Vector
• (Pathogenicity
  (diagnosis)
• and Prophylaxis)
• (Epidemiology and Prophylaxis)

Stage in man
Infective stage
Stage left man
Stage in environment (vector)
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• Infective stage(???)
• A stage of parasite which can enter the human
  body and develop continuously there.

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• Carrier
• Carrier is a person who carries a certain
  parasite without displaying any sign or symptom
  of diseases acting the source of infection

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Effects of the Parasite on the Host

• Parasite infection and parasitic disease.
• Overt symptoms of infection may depend on the
  number of worms present, the nutritional status
  of the host, or both.
• Injury to the host may be brought about in many
  ways.
• Interference with the vital processes of the host
  through the action of secretions, excretions, or
  other products of the parasite.
• Invasion and destruction of host tissue.
• Deprive essential substances of the host.

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Effects of the Host on the parasite

• The genetic constitution of the host.
• Absence of the Duffy blood P. vivax
• Sickle cell trait P. falciparum
• The diet or nutritional status of the host.
• A high-protein diet intestinal protozoa
• Carbohydrate in the diet tapeworms
• Nutritional status of the host

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• Innate immunity
• Acquired immunity
• Can be demonstrated in many parasitic disease
• Absolute immunity to reinfection is rarely
  following following protozoal infections and
  probably never with helminth infection. Just
  resists to hyperinfection.
• No long-lasting immunity maintains while the
  parasites are still in the body.
• Premuniton in malariaConcomitant immunity in
  schistosomiasis

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Epidemiology

• Source of infection
• patient, carrier and reservoir host
• Transmission route
• water, food, soil, air, insect vector and
  so on
• Susceptible population
• People except those will special
  background are all susceptible to parasitic
  infection.

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Epidemiological factors

• Natural factors
• Climate, geography, species of parasites and
  vectors
• Socio-economic factors
• Social system, economic situation, life condition
  and mode, hygienic condition
• Individual factors
• Sex, age, profession, ethnic group

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Control

• Destruction of source of infection
• Interruption of transmission
• Protection of susceptible population

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Prevalence of Parasitic Infections

• Malaria
• Infected, 400 to 490 million
• Annual deaths, 2.2 to 2.5 million

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• Schistosomiasis
• Infected, 150 million
• Annual deaths, 500,000 to 1 million

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• Lymphatic filariasis
• 128 million infected

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• Leishmaniasis
• Infected, 1.2 million

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• Hookworm
• 1.3 billion infected
• Amebiasis
• Infected, 1 world population
• Annual deaths, 40,000 to 110,000
• Ascariasis
• 1.3 billion infected
• Annual deaths (intestinal obstruction), 1550

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Important Groups of Human Parasites

• Helminthes
• Nematode
• Trematode
• Cestode

• Protozoa
• Amoeba
• Flagellate
• Sporidium
• Ciliate

• Arthropoda
• Mosquito
• Fly
• Tick
• Mite
• Bug
• Flea
• Lice

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Nematode

• The intestinal nematodes
• Ascaris
• Hook worm
• Pinworm
• Whip worm

• The blood- and tissue dwelling nematodes
• The filaria
• Trichinella

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Learning method

• Infective name Pathogenesis
• stage route Prevention
• mode
• Life cycle Pathogenic name Pathogenesis
• stage localization Treatment
• migration Diagnosis
• Diagnostic stage-morphology Diagnosis
• stage methods
• stage outside name
  Epidemiology
• (vector, other host) name
  Prevention