Microbiology Chapter 23 – Flashcards
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| How many kinds of protozoans are responsible for human illnesses? |
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| 25 |
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| Four groups of protozoans |
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| Sarcodinians Ciliates Flagellates Apicomplexons |
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| Cell cycle for protozoans |
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| Trophozoite Cyst |
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| Drugs for treating protozoan diseases? |
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| About 12 drugs are available, but are toxic to human cells. Metronidazole (target anaerobic cells that lack mitochondria) Quinine and Chloroquine (antimalarial drugs) No vaccines are available |
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| Entamoeba Histolytica |
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| World-wide, but highly prevalent in rural, third world countries Carried by 10% of world's population Infectious stage: cyst Route of transmission: fecal-oral Primary Target: intestine Reservoir: humans, food/water |
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| What does entamoeba histolytica cause? |
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| Amebiasis |
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| Forms of Intestinal Amebiasis |
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| Intestinal Amebiasis Extraintestinal Amebiasis |
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| Intestinal Amebiasis |
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| Severity varies with strain Erosive ulcers, colitis, diarrhea, cramps, dysentary |
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| Extraintestinal Amebiasis |
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| Trophozoites invade organs beyond intestine Necrotic lesions of brain, lungs, liver, kidneys |
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| Control/Prevention of Amebiasis |
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| Effective drugs Good hygiene Safe sex Disposal of human waste |
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| Naegleria Fowleri |
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| Inhibit warm, natural bodies of standing fresh water, swimming pools, hot tubs Infectious stage: trophozoite Route of transmission: nasal cavity and migrate to brain Target: Brain Rapid death - drugs are futile |
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| PAM |
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| Primary Amebic Meningoencephalitis |
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| Aconthamoeba |
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| Infectious stage: trophozoite Route of transmission: broken skin, orfices Drugs can help |
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| Control/Prevention of Aconthamoeba/Naegleria Fowleri |
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| Avoid still waters Attend to injured eyes Chlorinate swimming pools |
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| Balantidium Coli |
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| (The only infectious ciliate for humans) A zoonosis found world-wide from pigs/cattle/sheep/horses/water and food Infectious stage: cyst Route of transmission: oral-anal |
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| What disease does balantidium coli cause? |
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| Balantidiosis |
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| Intestinal Balantidiosis |
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| Trophozoites use cilia to burrow into mucosa Nausea/vomiting/diarrhea/dysentery Don't enter blood Have enormous nucleus |
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| Control/Prevention of Balantidiosis |
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| Don't ingest pig manure. |
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| Trichomonas Vaginalis causes...? |
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| Trichomoniasis |
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| Trichomonas Vaginalis |
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| Occurs world-wide among humans Sexually transmitted Pear shaped, four flagella Does not produce a cyst Reservoir=only humans, mostly among the promiscous Target=genitourinary tract Asymptomatic for 50% of cases |
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| Control/Prevention of Trichomoniasis |
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| Abstinence Condoms Mutual monogomy Treat with antiprotozoan drugs |
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| Giardia Lambia causes...? |
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| Giardiasis |
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| Giardia Lambia |
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| Reservoir: humans Transmitted through fecal-oral ingestion Infectious stage: cyst Target: small intestine Diarrhea, abdominal pain, flatulence Infections may resolve themselves |
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| Where do outbreaks of giardia lambia occur? |
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| Campers/hikers Daycare facilities Swimmers Pet owners Families |
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| Control/Prevention of Giardia Lambia |
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| Good hygiene Treat water Treat with antiprotozoan drugs |
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| How are hemoflagellates different from flagellates? |
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| Hemoflagellates are more complex. |
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| Infectous Hemoflagellates |
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| Vector borne parasites, live in blood/tissues Have more developmental stages |
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| Developmental stages for hemoflagellates |
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| Amastigote (no flagellate) Promastigote (bears flagellum) Epimastigote (bears flagellum + undulating membrane) Trypomastigote (Fully formed flagellate + undulating membrane). |
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| Trypanosoma causes what diseases? |
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| Trypanosoma brucei Trypanosoma cruzi |
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| Trypanosoma Brucei |
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| African sleeping sickness Endemic to central Africa Reservoir: mammals + humans Transmitted through Tetse flies (bite) Infectious stage: trophomastigote |
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| Symptoms of Trypanosoma |
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| Fever, joint pain, personality changes, sleep disturbances, neurological deterioration, coma, secondary infections, death |
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| Trypanosoma Cruzi |
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| Kissing bug (corner of mouth/eye) From Reduvid bugs (which defecate when they bite) Chagas disease Endemic to central America Reservoir: humans |
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| Control/Prevention of Trypanosoma |
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| Drugs Screen blood transformations Eliminate biological vector |
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| Leishmania species causes...? |
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| Leishmaniasis |
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| Leishmania |
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| Endemic to equatorial regions Transmitted through sand flies Reservoir: animals Infectious stage: promastigote |
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| Forms of Leishmania |
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| Cutaneous leishmaniasis Mucocutaneous leishmaniasis Visceral Leishmaniasis |
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| Control/Prevention of Leishmaniasis |
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| Drugs Milder forms help immunity develop Control of sand flies |
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| Characteristics of Apicomplexon Parasites |
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| Nearly all are parasitic to humans No locomotor organelles Complex life stages/alternate between sexual/asexual phases |
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| Plasmodium species |
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| Causes malaria Endemic to equatorial regions The dominant protozoan disease Threatens 40% of world's population From Anopheles mosquitos |
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| What did DDT do? |
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| It killed off the mosquitos, but was incorrectly banned because it was thought to threaten wildlife. |
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| Infectious stage of Plasmodium species? |
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| Sporozites |
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| Life cycle of Plasmodium |
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| Enters blood Liver cells are targeted Divide and multiply into merozoites Liver cells rupture, release into RBCs Transform into trophozoite stage Feed on hemoglobin RBCs rupture, release merozoites to other rbcs (CAUSES FEVER) Mosquito takes RBCs to its stomach Gameocytes produce oocysts |
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| Symptoms of Malaria |
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| Malaise Fever Fatigue Aches Nausea Bouts of fever/chills Hemolyptic anemia, rupturing of the liver, spleen, kidney Subject may relapse for five years, maybe longer |
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| Control/Prevention of Malaria |
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| Treatment with quinine/chloroquine Vector control No vaccine |
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| Toxoplasma Gondii causes... |
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| Toxoplasmosis |
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| Toxoplasmosis |
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| Occurs world-wide Reservoir: Birds, mammals, mice Infectious stage: tachyzoites |
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| How can toxoplasmosis be transmitted to humans? |
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| Ingestion of undercooked meat Ingestion of oocysts from contaminated sources Inhalation of oocysts Transplacental Route |
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| Consequences of toxoplasmosis? |
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| Most cases are asymptomatic In the immune compromised, chronic infections=brain lesions Fetal infection |
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| Consequences of fetal infection of toxoplasmosis? |
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| Pregnant women who are infected have a one in three chance of infecting the fetus. First/Second trimester infections: Stillbirths Enlarged liver/spleen Hydroencephalis Convulsions Blindness |
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| Control/Prevention of Toxoplasmosis |
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| Drugs can effectively treat Cook/freeze meat correctly Hygiene + sanitation |
