VIII. Protozoan Diseases

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VIII. Protozoan Diseases

• A. Basic Properties of Protozoa
• B. Amebiasis
• C. Primary Amebic Meningoencephalitis
• D. Giardiasis
• E. Trichomoniasis
• F. Balantidiasis
• G. Toxoplasmosis
• H. Malaria
• I. Cryptosporidiosis
• J. Pneumocystosis

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VIII. A. Basic Properties of Protozoa

• Cellular properties
• Eukaryotic microorganisms having animal-like
  cells
• No cell walls
• Most have heterotrophic metabolisms
• A few protozoa (eg Euglena) are photosynthetic

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VIII. A. Basic Properties of Protozoa

• Cellular properties (cont.)
• Many are free-living in soil or aquatic
  environments a few are parasitic
• Single-celled or simple colonial organization
• Classification based predominately on the
  mechanism of motility

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VIII. A. Basic Properties of Protozoa

• Classification
• Class Sarcodina
• Motile by pseudopodia amoeboid movement
• Amebas, radiolaria, and foraminifera
• Examples
• Amoeba
• Entamoeba histolytica
• Naegleria fowleri

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VIII. A. Basic Properties of Protozoa

• Classification (cont.)
• Class Mastigophora
• Motile by flagella
• Examples
• Euglena
• Giardia lamblia
• Trichomonas vaginalis

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VIII. A. Basic Properties of Protozoa

• Classification (cont.)
• Class Ciliophora
• Motile by cilia
• Examples
• Paramecium
• Balantidium coli

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VIII. A. Basic Properties of Protozoa

• Classification (cont.)
• Class Sporozoa
• A class of parasitic protozoa
• Most have complex life cycles with both sexual
   asexual stages
• Adult forms are nonmotile
• Examples
• Plasmodium
• Toxoplasma gondii

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VIII. A. Basic Properties of Protozoa

• Trophozoite and Cyst
• Some protozoa go through different stages in
  their life cycle.
• This is especially true of certain parasitic
  protozoa.
• Trophozoite Actively growing and reproducing
  stage
• Cyst A dormant stage, enclosed in a resistant
  cyst coat

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VIII. B. Amebiasis

• Cause Entamoeba histolytica
• A parasitic ameba class Sarcodina
• Transmitted via contaminated food water
• Cysts are shed in the feces
• When ingested Excystation occurs in the
  intestine
• Trophozoites grow reproduce in the intestinal
  tract

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VIII. B. Amebiasis

• Symptoms
• Abdominal pain
• Little diarrhea but often blood in the stool
  (amebic dysentery)
• Possibly of intestinal ulceration perforation
  infection of internal organs such as liver lungs

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VIII. C. Primary Amebic Meningoencephalitis

• Cause Naegleria fowleri
• A fresh water, free living ameba
• No cyst stage
• Several cases of infections in swimmers
• Transmission and Symptoms
• Transmission through the nasal sinus passages
• Infection of the brain meninges
• Headaches delirium seizures

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VIII. D. Giardiasis

• Cause Giardia lamblia
• A flagellate of class Mastigophora
• The trophozoite has four pairs of flagella two
  nuclei giving it a face-like appearance
• Grows in the intestinal tract
• Cysts are shed in the feces

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VIII. D. Giardiasis

• Transmission and Symptoms
• Transmitted via contaminated water food
• Foul-smelling profuse diarrhea
• Sometimes chronic
• Often misdiagnosed
• Diagnosis via microscopic examination
• Enterotest capsule

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VIII. E. Trichomoniasis

• Cause Trichomonas vaginalis
• Flagellate of the class Mastigophora
• No cyst stage
• Transmission Symptoms
• Transmitted via sexual contact
• Genital itching
• Painful urination with a white, mucoid discharge
• Occasional reduction of sperm count or erosion of
  the cervix

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VIII. F. Balantidiasis

• Cause Balantidium coli
• Ciliated, in Class Ciliophora
• Trophozoites grow in the intestinal tract
• Cysts are shed in the feces and may remain
  embedded in intestinal walls, causing chronic
  infections
• Transmission Symptoms
• Contaminated water food
• Ulceration in intestines
• Profuse diarrhea

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VIII. G. Toxoplasmosis

• Cause Toxoplasma gondii
• In Class Sporozoa
• Both asexual sexual stages
• Invasion of several areas of the body, including
  internal organs  muscle tissue
• Possibly the most prevalent protozoan parasite of
  humans

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VIII. G. Toxoplasmosis

• Transmission Symptoms
• Transmitted via eating contaminated meat
• Cysts are found in the meat, especially of
  grazing animals such as cattle
• Cats can transmit the disease through their feces
• Lymph node swelling flu-like symptoms

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VIII. G. Toxoplasmosis

• Transmission Symptoms (cont.)
• Generally mild in non-immunosuppressed persons
• Severe infections in immunosuppressed persons
• Pregnant women are in danger of fetal damage or
  miscarriage

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VIII. H. Malaria

• Cause Plasmodium species
• In Class Sporozoa
• Complex life cycle requiring two hosts a mammal
  (human) and the mosquito Anopheles

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VIII. H. Malaria

• Transmission and Symptoms
• The asexual merozoite stage infects human blood
  from the bite of a mosquito
• The parasite invades erythrocytes reproduces
• Erythrocytes break open release the parasite
  this causes the characteristic fever, chills,
  anemia, weakness, hemorrhaging
• Intense fever chills about 48 - 72 hr after
  exposure, due to the simultaneous rupture of so
  many erythrocytes

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VIII. H. Malaria

• Transmission and Symptoms (cont.)
• The sexual stage of Plasmodium develops in the
  human host and is picked up by a mosquito
• The sexual stage is completed in the salivary
  gland of the mosquito to complete the cycle
• Treatment by quinine other antimalarial drugs

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VIII. I. Cryptosporidiosis

• Cause Cryptosporidium species
• In class Sporozoa
• A common protozoan parasite in humans
• Transmission and Symptoms
• Contaminated water
• Mild diarrhea in non-immunosuppressed persons
• Severe diarrhea in immunosuppressed persons

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VIII. J. Pneumocystosis

• Cause Pneumocystis carinii
• Usually classified as a protozoan of class
  Sporozoa, but recent evidence suggests that it
  may be a fungus
• Transmission and Symptoms
• Transmitted by airborne contact
• Usually asymptomatic or with mild respiratory
  symptoms
• Causes severe pneumonia in immunocompromised
  persons
• A major secondary infection cause of death in
  AIDS patients