Protozoan microorganisms Flashcards
Parasite
- Living eukaryote organism, which takes its nourishment and other needs from a host.
- Depends on the host for nutrition
- Microbes can establish parasitic relationships with the host
ENDOparasites
- Inside of the host’s body - Permanently
- Some anaerobes, some aerobes
- Example Protozoa and helminths
ECTOparasites
- ON the outer surface of the host’s body – temporary or permanent
- Aerobes
- Some ectoparasites serve as vectors of pathogens
- Example ticks, fleas, lice, and mites
ENDOPARASITES
Protoza
- Monocellular and mostly asexual reproduction and sexual reproduction
- Non-motile, those motile use either flagella or
cilia
ENDOPARASITES
Helminths
- Pluricellular, Parasitic
worms - Sexual reproduction
- Move through muscular contractions
Protozoa general characteristics
- Chemoheterotrophs
- Preformed organic substances
- Similar requirements of the mammalian cells
- Require high moisture
- Diverse Oxygen requirements
- Parasitic relationship with many hosts
Life stages of protazoa
- Exists in 2 morphological form
- Trophozoite - motile form, activly feed and multiply and pathogenic form
- Cyst - External non-parasitic form possessing protective membrane or wall
Transmission of intestinal protozoa
- Transmission of intestinal protozoa that live in a human’s intestine to another human typically
occurs through a fecal-oral route - Contaminate food water pets and waste water
- Multipy in gut and cause infections
Medically relevant protozoa
- Protozoan infections can be mild in normal individuals, yet life-threatening in immunosuppressed patients
Amoebae
- Amoeboid movement
- Move by extending pseudopods arm like projections
- Engulf food with pseudopods and phagocytize - feeds on red blood cells
Flagellates
- One or more flagella
- Intestinal and genito-urinary flagellates
- Blood and tissue flagellates
Transmission of blood borne protozoa - Leishmania
- Parasitise in mononuclear
phagocytic cells - Leishmania protozoa are usually spread through the bite of infected sand flies
Cutaneous leishmaniasis
- Affects the skin
Mucosal leishmaniasis
Affects the mucous membranes of
the nose and mouth, causing sores and destroying tissues
Visceral leishmaniasis
- Affects the internal organs,
particularly the bone marrow, lymph nodes, liver, and spleen
Trichomoniasis
- Gential tract infection Trichomonas vaginalis
- Common STD
Ciliates
- Complex protozoa that move by cilia
- Unusually, they have two different types of nuclei
- Transmitted through infected pigs
- Also oral-fecal transmission
Sporozoa
- Complex life cycles
- Alternating sexual and asexual reproduction, also involving spores
- Usually, they have more than one host
- Diarrheal disease
- Intestinal illness
- Non-motile prodcing protazoa
Plasmodium
- Responsible for malaria
- Obligate intracellular parasite
4 species responsible for malaria
- P. malariae
- P. vivax
- P. falciparum
- P. ovale
- P. falciparum
Transmission of malaria
- Spread to humans by the bite of female mosquitoes of the genus Anopheles
- Blood transfusions
- Mother to fetus
Endemic
- Subtropic
countries with a temperate climate
Acute febrile illness
- Symptoms after 10-14 days from mosquito’s bite
Control of malaria
- Vaccine available showing modest efficacy, preventing about 30% of severe malaria cases
Drugs that prevent malaria
Doxycycline - starting 1 to 2 days before travel
Personal protection against bites
- DEET 50% insect repellan covering clothes
Antiprotozoal drugs
- Specific geographic locales
- Unicellular eukaryotes, less easily treated than bacterial infections
- Not completely elucidated
- Toxic effects in the host
- may not be suitable to pregnant
Microscopic examination
Identify the morphology of microbes in specimens
Immunologic tests
- Detect antibodies or microbial antigens detect microbial protien
Molecular methods
- Polymerase Chain Reaction (PCR) based techniques allow amplification of a known gene of interest
- Nucleic acid sequencing