Chapter 12: The Eukaryotes: Fungi, Algae, Protozoa, Helminths <ul><li>Mycology is the study of fungi </li></ul><ul><li>Myc...
Molds and fleshy fungi - multicellular <ul><li>Thallus  =  body  consist of long filaments of cells joined together =  hyp...
Yeasts - unicellular <ul><li>Budding (reproduction) – yeast forms a bud on its surface that elongates </li></ul><ul><ul><l...
Yeasts - unicellular <ul><li>Capable of facultative anaerobic growth </li></ul><ul><ul><li>Aerobic respiration </li></ul><...
Saccharomyces cerevisiae
Dimorphic fungi – most are pathogenic <ul><li>Dimorphism = 2 forms of growth – yeast or mold </li></ul><ul><ul><li>Tempera...
Asexual spores <ul><ul><li>Conidiospores  Pg 349 </li></ul></ul><ul><ul><ul><li>Produced in a chain at the end of a coniop...
Asexual spores <ul><li>Chlamydoconidium – spore formed within a hyphal segment ex.  Candia albicans </li></ul><ul><li>Spor...
Conidiospores -  Aspergillus
Sexual reproduction <ul><li>Sexual spores result from the fusion of nuclei from 2 opposite mating strains  </li></ul><ul><...
Classification of fungi by phylum <ul><li>Zygomycota  = conjugation fungi, bread molds ex.  Rhizopus stolonifer </li></ul>...
Classification of fungi by phylum <ul><li>Ascomycota  - sac fungi  ex.  Aspergillus   niger   (used to make Beano),  Penic...
Classification of fungi by phylum <ul><li>Basidiomycota  –  club fungus , mushrooms ex.  Cryptococcus   neoformans  (inhal...
Fungal infection = mycosis 5 classifications <ul><li>Systemic mycoses – infection deep  within the body </li></ul><ul><ul>...
Fungal infection = mycosis 5 classifications <ul><li>Subcutaneous mycoses  –  infection beneath the skin  caused by saprop...
Subcutaneous Mycoses
Superficial Mycosis
Superficial Mycosis
Fungal infection = mycosis 5 classifications <ul><li>Superficial mycosis  – along hair shafts, surface epidermal cells, fo...
Fungal infection = mycosis 5 classifications <ul><li>Opportunistic pathogen cont.  </li></ul><ul><ul><li>Aspergillosis  – ...
Superficial Mycosis Ringworm, stained preparation, macroconidia of Microsporum canis 
Superficial Mycosis Ringworm 
Lichens <ul><li>Are a  combination  of a a  green alga  or a  cyanobacterium  and a  fungus  growing together in a  mutual...
Lichens <ul><li>Are used for indicator organisms for air pollution </li></ul><ul><li>Some lichens cause allergic contact d...
Algae  <ul><li>Are unicellular or multicellular  </li></ul><ul><li>Habitat – aquatic, soil, trees, hair of sloths or polar...
Algae Phyla <ul><li>Chlorophyta = green algae  – usually microscopic, contains chlorophyll a and b </li></ul><ul><ul><li>B...
Algae Phyla <ul><li>Dinoflagellata = dinoflagellates </li></ul><ul><ul><li>Unicellular algae, major part of phytoplankton ...
Algae Phyla <ul><li>Oomycota = water molds   pg   360 pix  Decomposers that form cottony masses in fresh H2O </li></ul><ul...
algae <ul><li>80% of Earth’s O2 is produced by planktonic algae as a by product of photosynthesis </li></ul><ul><li>Increa...
Protozoa = 1 st  animal single celled <ul><li>Trophozoite  = feeding or growing stage </li></ul><ul><li>Reproduce asexuall...
Protozoa <ul><li>Are aerobic heterotrophs but many intestinal protozoa are capable of anaerobic growth  </li></ul>
Medically important Phyla of protozoa  chart pg 367 <ul><li>Archaezoa  – eukaryotes that lack mitochondria </li></ul><ul><...
Medically important Phyla <ul><li>Microspora  – obligate intracellular parasites that also lack mitochondria </li></ul><ul...
Medically important Phyla <ul><li>Acanthamoeba  </li></ul><ul><ul><li>Can grow in tap water and infects the cornea of the ...
Life cycle of Plasmodium pg 365 <ul><li>Definitions: </li></ul><ul><ul><li>Trophozoites  – feeding or growing stage </li><...
Life cycle of Plasmodium in humans <ul><li>Humans  – intermediate hosts, asexual reproduction takes place  </li></ul><ul><...
Life cycle of Plasmodium in humans <ul><li>Humans </li></ul><ul><ul><li>Merozoites  leave the liver to infect RBCs </li></...
Life cycle of Plasmodium in Mosquitos <ul><li>Mosquitos  –  definitive hosts , sexual reproduction takes place  </li></ul>...
Apicomplexa continued <ul><li>Cryptosporidium  – causes intestinal infection </li></ul><ul><ul><li>Transmission is by fece...
Medically important Protozoan Phyla <ul><li>Ciliophora  – ciliates, cilia for movement and to bring food into mouth </li><...
Phylum Euglenozoa <ul><li>Euglenoids  cont. </li></ul><ul><ul><li>Pellicle = semi-rigid plasma membrane </li></ul></ul><ul...
Helminths – parasitic worms  <ul><li>Phylum  Platyhelminthes  =  flatworms </li></ul><ul><ul><li>2 groups = trematodes and...
Helminths – parasitic worms <ul><li>Paragonimus westermani   cont . </li></ul><ul><ul><li>Sputum w/ eggs is coughed up, sw...
Helminths – parasitic worms <ul><li>Cestodes = tapeworms </li></ul><ul><ul><li>Lack a digestive tract, absorb nutrients th...
Cestodes = tapeworms <ul><li>Humans as  definitive hosts </li></ul><ul><ul><li>Taenia saginata  – beef tapeworm </li></ul>...
Cestodes = tapeworms <ul><li>Humans as  definitive hosts  cont. </li></ul><ul><ul><li>Taenia solium  = pork tapeworm </li>...
Tapeworm Life Cycle
Cestodes = tapeworms <ul><li>Humans as intermediate hosts   pg 375 </li></ul><ul><ul><li>Echinococcus granulosus  = dog ta...
Nematoda   =  roundworms <ul><li>Free-living and parasitic </li></ul><ul><li>Cylindrical, tapered at each end </li></ul><u...
Nematode  eggs infective  for humans <ul><li>Enterobius vermicularis  = pinworm </li></ul><ul><ul><li>Spends entire life i...
Pinworm Life Cycle
Pinworms on Perianal Folds
Nematode  eggs infective  for humans <ul><li>Ascaris lumbricoides  – large (30 cm), infects over 1 billion ww </li></ul><u...
Nematode  larvae infective  for humans <ul><li>Necator americanus, Ancylostoma duodenale  = adult  hookworms  that live in...
Nematode  larvae infective  for humans <ul><li>Trichinella spiralis  – causes  trichinellosis  by eating undercooked pork ...
Arthropods = Insects, Arachnids <ul><li>Have segmented bodies, hard external skeletons, jointed legs </li></ul><ul><li>If ...
Body & Crab Lice
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  • Eggs are deposited on perianal folds .  Self-infection occurs by transferring infective eggs to the mouth with hands that have scratched the perianal area .  Person-to-person transmission can also occur through handling of contaminated clothes or bed linens.  Enterobiasis may also be acquired through surfaces in the environment that are contaminated with pinworm eggs (e.g., curtains, carpeting).  Some small number of eggs may become airborne and inhaled.  These would be swallowed and follow the same development as ingested eggs.  Following ingestion of infective eggs, the larvae hatch in the small intestine and the adults establish themselves in the colon .  The time interval from ingestion of infective eggs to oviposition by the adult females is about one month.  The life span of the adults is about two months.  Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area .  The larvae contained inside the eggs develop (the eggs become infective) in 4 to 6 hours under optimal conditions .  Retroinfection, or the migration of newly hatched larvae from the anal skin back into the rectum, may occur but the frequency with which this happens is unknown. Geographic Distribution: Worldwide, with infections more frequent in school- or preschool- children and in crowded conditions.  Enterobiasis appears to be more common in temperate than tropical countries.  The most common helminthic infection in the United States (an estimated 40 million persons infected).   http://www.dpd.cdc.gov/dpdx/HTML/Enterobiasis.htm
  • Eggs are deposited on perianal folds .  Self-infection occurs by transferring infective eggs to the mouth with hands that have scratched the perianal area .  Person-to-person transmission can also occur through handling of contaminated clothes or bed linens.  Enterobiasis may also be acquired through surfaces in the environment that are contaminated with pinworm eggs (e.g., curtains, carpeting).  Some small number of eggs may become airborne and inhaled.  These would be swallowed and follow the same development as ingested eggs.  Following ingestion of infective eggs, the larvae hatch in the small intestine and the adults establish themselves in the colon .  The time interval from ingestion of infective eggs to oviposition by the adult females is about one month.  The life span of the adults is about two months.  Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area .  The larvae contained inside the eggs develop (the eggs become infective) in 4 to 6 hours under optimal conditions .  Retroinfection, or the migration of newly hatched larvae from the anal skin back into the rectum, may occur but the frequency with which this happens is unknown. Geographic Distribution: Worldwide, with infections more frequent in school- or preschool- children and in crowded conditions.  Enterobiasis appears to be more common in temperate than tropical countries.  The most common helminthic infection in the United States (an estimated 40 million persons infected).   http://www.dpd.cdc.gov/dpdx/HTML/Enterobiasis.htm
  • Chapter 12 Micro

    1. 1. Chapter 12: The Eukaryotes: Fungi, Algae, Protozoa, Helminths <ul><li>Mycology is the study of fungi </li></ul><ul><li>Mycosis = fungal disease </li></ul><ul><li>All fungi are Chemoheterotrophs – live on preformed organic matter </li></ul><ul><ul><li>Excrete extracellular enzymes to digest organic matter and break it down to simple products that it absorbs </li></ul></ul><ul><ul><li>Major decomposer of dead plant matter which recycles elements </li></ul></ul><ul><ul><ul><li>Ex. Cellulase: cellulose (plants, wood) to glucose used for energy </li></ul></ul></ul><ul><ul><li>Most are aerobic (molds) or facultative anaerobes (yeasts) </li></ul></ul>
    2. 2. Molds and fleshy fungi - multicellular <ul><li>Thallus = body consist of long filaments of cells joined together = hyphae </li></ul><ul><ul><li>Septate – partitions between cells, may have pores between cells so cytoplasm mixes with adjacent cells, 1 or 2 nuclei/cell </li></ul></ul><ul><ul><li>Coencytic = non septate, many nuclei </li></ul></ul><ul><ul><li>Hyphae grow by elongating at tips, fragmentation </li></ul></ul><ul><ul><li>Vegetative hyphae – obtains nutrients </li></ul></ul><ul><ul><li>Aerial hyphae- bears reproductive spores </li></ul></ul><ul><ul><li>Mass of hyphae = mycelium </li></ul></ul><ul><ul><li>Cell walls contain chitin , same as exoskeletons of arthropods ex Insects </li></ul></ul>
    3. 3. Yeasts - unicellular <ul><li>Budding (reproduction) – yeast forms a bud on its surface that elongates </li></ul><ul><ul><li>Parent cell nucleus divides, one nucleus migrates into the bud </li></ul></ul><ul><ul><li>Cell wall forms between yeast and bud and bud breaks off </li></ul></ul><ul><li>Pseudohyphae = buds fail to detach and from a short chain of cells </li></ul><ul><ul><li>Candida albicans – attaches to epithelial cells as yeast but forms pseudohyphae to invade deeper into tissue </li></ul></ul>
    4. 4. Yeasts - unicellular <ul><li>Capable of facultative anaerobic growth </li></ul><ul><ul><li>Aerobic respiration </li></ul></ul><ul><ul><ul><li>Yeast + O2 metabolize CH2Os to CO2 + H2O </li></ul></ul></ul><ul><ul><li>Anaerobic respiration </li></ul></ul><ul><ul><ul><li>Yeasts without O2 ferments CH2Os to ethanol and CO2 </li></ul></ul></ul><ul><ul><ul><ul><li>Brewing, wine making, baking industries </li></ul></ul></ul></ul>
    5. 5. Saccharomyces cerevisiae
    6. 6. Dimorphic fungi – most are pathogenic <ul><li>Dimorphism = 2 forms of growth – yeast or mold </li></ul><ul><ul><li>Temperature dependent </li></ul></ul><ul><ul><ul><li>Moldlike at 25 degrees C </li></ul></ul></ul><ul><ul><ul><li>Yeasts at 37 degrees C </li></ul></ul></ul><ul><li>Life cycle </li></ul><ul><ul><li>Filamentous fungi can reproduce asexually – fragmentation or spores and reproduce sexually by spores </li></ul></ul><ul><ul><li>Fungal spores can survive hot, dry environments but not like endospores </li></ul></ul><ul><li>Asexual spores – produced by hyphae of a single fungus </li></ul><ul><ul><li>Conidiospores = conidium (pl. conidia) = uni or multicellular spores not enclosed in a sac </li></ul></ul>
    7. 7. Asexual spores <ul><ul><li>Conidiospores Pg 349 </li></ul></ul><ul><ul><ul><li>Produced in a chain at the end of a coniophore ex. Aspergillus </li></ul></ul></ul><ul><ul><ul><li>Arthroconidia – formed by fragmentation ex. Coccidiodes immitis – pulmonary mycoses </li></ul></ul></ul><ul><ul><ul><li>Blastoconidia buds coming off parent cell – some yeasts ex. Candida albicans, Cryptococcus (lungs) </li></ul></ul></ul>
    8. 8. Asexual spores <ul><li>Chlamydoconidium – spore formed within a hyphal segment ex. Candia albicans </li></ul><ul><li>Sporangiospore – spore formed in a sac = sporangium at the end of an aerial hyphae called a sporangiophore ex. Rhizopus </li></ul>
    9. 9. Conidiospores - Aspergillus
    10. 10. Sexual reproduction <ul><li>Sexual spores result from the fusion of nuclei from 2 opposite mating strains </li></ul><ul><li>Pg. 350 shows both asexual and sexual reproduction in Rhizopus </li></ul>
    11. 11. Classification of fungi by phylum <ul><li>Zygomycota = conjugation fungi, bread molds ex. Rhizopus stolonifer </li></ul><ul><ul><li>Hyphae = coenocytic </li></ul></ul><ul><ul><li>Asexual reproduction = sporangiospores </li></ul></ul><ul><ul><li>Sexual reproduction = zygospores = thick walled spores formed from union of 2 opposite mating strains </li></ul></ul><ul><ul><li>Habitat = soil, saprophytic = lives on decaying plant material </li></ul></ul>
    12. 12. Classification of fungi by phylum <ul><li>Ascomycota - sac fungi ex. Aspergillus niger (used to make Beano), Penicillium (Abs) </li></ul><ul><ul><li>Hyphae – septate, some yeasts </li></ul></ul><ul><ul><li>Asexual reproduction = conidia (means dust, becomes airborne) </li></ul></ul><ul><ul><li>Sexual reproduction = ascospores which are contained in an ascus </li></ul></ul><ul><ul><li>Habitat = soil, saprophytic </li></ul></ul>
    13. 13. Classification of fungi by phylum <ul><li>Basidiomycota – club fungus , mushrooms ex. Cryptococcus neoformans (inhalation of spores causes lung disease) </li></ul><ul><ul><li>Hyphae = septate </li></ul></ul><ul><ul><li>Asexual reproduction = fragmentation </li></ul></ul><ul><ul><li>Sexual reproduction = basidiospores </li></ul></ul><ul><ul><li>Habitat = soil, bird feces </li></ul></ul>
    14. 14. Fungal infection = mycosis 5 classifications <ul><li>Systemic mycoses – infection deep within the body </li></ul><ul><ul><li>Can infect a # of tissues and organs </li></ul></ul><ul><ul><li>Transmission – inhalation of spores </li></ul></ul><ul><ul><ul><li>Enters the lungs and then spreads to other body tissues </li></ul></ul></ul><ul><ul><ul><li>Not contagious </li></ul></ul></ul><ul><ul><li>Live in soil </li></ul></ul><ul><ul><li>Histoplasmosis and coccidiodomycosis – both pulmonary mycosis </li></ul></ul>
    15. 15. Fungal infection = mycosis 5 classifications <ul><li>Subcutaneous mycoses – infection beneath the skin caused by saprophytic fungi that live in the soil and on vegetation </li></ul><ul><ul><li>Transmission – by direct implantation of spores or hyphae into puncture wounds </li></ul></ul><ul><li>Cutaneous mycoses </li></ul><ul><ul><li>Dermatophytes = fungi that live only on epidermis, </li></ul></ul><ul><ul><li>hair, nails </li></ul></ul><ul><ul><li>Secrete enzyme keratinase wh/ degrades keratin in hair, skin, nails </li></ul></ul><ul><ul><li>Transmission – direct contact – human to human, animal to human </li></ul></ul>
    16. 16. Subcutaneous Mycoses
    17. 17. Superficial Mycosis
    18. 18. Superficial Mycosis
    19. 19. Fungal infection = mycosis 5 classifications <ul><li>Superficial mycosis – along hair shafts, surface epidermal cells, found in the tropics ex. Ringworm </li></ul><ul><li>Opportunistic pathogen – normally harmless but is pathogenic in debilitated host , ex. Ab tx, lung disease, immune disorder </li></ul><ul><ul><li>Pneumocystis – leading cause of death in AIDS px </li></ul></ul><ul><ul><li>Mucormycosis – Rhizopus , Mucor – px w/ diabetes, leukemia, or being txed w/ immunosuppressive drugs </li></ul></ul>
    20. 20. Fungal infection = mycosis 5 classifications <ul><li>Opportunistic pathogen cont. </li></ul><ul><ul><li>Aspergillosis – Aspergillus – px w/ lung disease, cancer who have inhaled the spores </li></ul></ul><ul><ul><li>Cryptococcus and Penicillium – can be fatal to AIDS px </li></ul></ul><ul><ul><li>Yeast infections (candidiasis) – Candida albicans – occurs vaginally or as thrush in newborns, AIDS px, or px on Abs </li></ul></ul>
    21. 21. Superficial Mycosis Ringworm, stained preparation, macroconidia of Microsporum canis 
    22. 22. Superficial Mycosis Ringworm 
    23. 23. Lichens <ul><li>Are a combination of a a green alga or a cyanobacterium and a fungus growing together in a mutualistic relationship – both benefit </li></ul><ul><li>The algae provide the nutrients and the fungi provide attachment and protection from desiccation </li></ul><ul><li>Provides erythrolitmin - dye used in litmus paper </li></ul>
    24. 24. Lichens <ul><li>Are used for indicator organisms for air pollution </li></ul><ul><li>Some lichens cause allergic contact dermatitis in humans </li></ul><ul><li>Major food source for caribou and reindeer </li></ul><ul><ul><li>After the 1986 Chernobyl nuclear disaster, lichens absorbed radioactive cesium -137 from the air and 70,000 reindeer raised for food in Lapland had to be destroyed </li></ul></ul>
    25. 25. Algae <ul><li>Are unicellular or multicellular </li></ul><ul><li>Habitat – aquatic, soil, trees, hair of sloths or polar bears </li></ul><ul><li>Algae phyla </li></ul><ul><ul><li>Phaeophyta – brown algae = kelp – macroscopic in coastal waters </li></ul></ul><ul><ul><ul><li>Algin –thickener used in foods extracted from CW </li></ul></ul></ul><ul><ul><li>Rhodophyta = red algae –live at greater ocean depths than other algae </li></ul></ul><ul><ul><ul><li>Lab agar comes from red algae </li></ul></ul></ul><ul><ul><ul><li>Carrageenan and agar used as thickening ingredients in foods and pharmaceutical agents </li></ul></ul></ul>
    26. 26. Algae Phyla <ul><li>Chlorophyta = green algae – usually microscopic, contains chlorophyll a and b </li></ul><ul><ul><li>Believed to have given rise to terrestrial plants </li></ul></ul><ul><ul><li>Unicellular or multicellular - can form filaments </li></ul></ul><ul><li>Bacillariophyta = diatoms </li></ul><ul><ul><li>Unicellular or filamentous w/ CWs of pectin and silica that fit together like a Petri dish </li></ul></ul><ul><ul><li>One of major algae in the oceanic food chain (phytoplankton) </li></ul></ul><ul><ul><li>Used as polishing and insulating materials </li></ul></ul><ul><ul><li>Diatomaceous earth – filtering material </li></ul></ul>
    27. 27. Algae Phyla <ul><li>Dinoflagellata = dinoflagellates </li></ul><ul><ul><li>Unicellular algae, major part of phytoplankton </li></ul></ul><ul><ul><li>Some produce neurotoxins and are responsible for many fish, marine mammals and some human deaths </li></ul></ul><ul><ul><li>Large concentrations – ocean deep red color = red tide </li></ul></ul><ul><ul><ul><li>Mollusks shouldn’t be harvested during a red tide- concentrates neurotoxin and causes paralytic shellfish poisoning </li></ul></ul></ul>
    28. 28. Algae Phyla <ul><li>Oomycota = water molds pg 360 pix Decomposers that form cottony masses in fresh H2O </li></ul><ul><li>Used to be classified as fungi but DNA analysis confirms they are more closely related to diatoms and dinoflagellates </li></ul><ul><li>Responsible for Ireland’s great potato blight in 1800’s – millions died </li></ul><ul><li>Zoospores = flagellated spores w/ 2 flagella </li></ul><ul><li>Causes mildew on grapes, effects fruit and veg crops </li></ul>
    29. 29. algae <ul><li>80% of Earth’s O2 is produced by planktonic algae as a by product of photosynthesis </li></ul><ul><li>Increase in numbers of planktonic algae causes algal blooms </li></ul><ul><li>When algae die in large numbers their decomposition depletes the level of dissolved O2 in the H2O – may kill fish </li></ul>
    30. 30. Protozoa = 1 st animal single celled <ul><li>Trophozoite = feeding or growing stage </li></ul><ul><li>Reproduce asexually by fission, budding or schizogony (multiple fission) </li></ul><ul><li>Sexual reproduction in some protozoa </li></ul><ul><ul><li>Ex. Ciliate - Paramecium by conjugation see pg. 362 fig. 12.16 </li></ul></ul><ul><li>Can form cyst stage to survive when food, moisture, O2 are lacking, temp not right, toxic chemicals are present </li></ul><ul><ul><li>Cysts can survive outside the host when excreted – ready for new host </li></ul></ul>
    31. 31. Protozoa <ul><li>Are aerobic heterotrophs but many intestinal protozoa are capable of anaerobic growth </li></ul>
    32. 32. Medically important Phyla of protozoa chart pg 367 <ul><li>Archaezoa – eukaryotes that lack mitochondria </li></ul><ul><ul><li>2 or more flagella – whip like </li></ul></ul><ul><ul><li>Trichomonas vaginalis – urinary and genital tract infections </li></ul></ul><ul><ul><ul><li>Has undulating membrane (pg 363) and no cyst stage </li></ul></ul></ul><ul><ul><ul><li>Transmitted by sexual intercourse, toilet seats, towels </li></ul></ul></ul><ul><ul><li>Giardia lamblia (intestinales) – found in small intestine of mammals </li></ul></ul><ul><ul><ul><li>Excreted in feces as cysts to be ingested by next host </li></ul></ul></ul><ul><ul><ul><li>Dx = id cysts in feces </li></ul></ul></ul>
    33. 33. Medically important Phyla <ul><li>Microspora – obligate intracellular parasites that also lack mitochondria </li></ul><ul><ul><li>Cause chronic diarrhea and keratoconjuctivitis (inflammation of the conjunctiva) esp. in AIDS pxs </li></ul></ul><ul><li>Amoebozoa – move and engulf food by pseudopods </li></ul><ul><ul><li>Entamoeba histolytica – only pathogenic amoeba found in human intestine – 10% pop. May be infected </li></ul></ul><ul><ul><ul><li>Causes amoebic dysentery </li></ul></ul></ul><ul><ul><ul><li>Transmitted by ingestion of cyst excreted in feces </li></ul></ul></ul>
    34. 34. Medically important Phyla <ul><li>Acanthamoeba </li></ul><ul><ul><li>Can grow in tap water and infects the cornea of the eye and cause blindness </li></ul></ul><ul><li>Apicomplexa – intracellular parasites whose life cycle involves several hosts </li></ul><ul><ul><li>Ex. Plasmodium vivax causes malaria, transmitted to humans by female Anopheles mosquito </li></ul></ul>
    35. 35. Life cycle of Plasmodium pg 365 <ul><li>Definitions: </li></ul><ul><ul><li>Trophozoites – feeding or growing stage </li></ul></ul><ul><ul><ul><li>Sporozoites – in mosquito </li></ul></ul></ul><ul><ul><ul><li>Merozoites – in humans </li></ul></ul></ul><ul><ul><li>Intermediate host - organism that harbors the larval or asexual stage </li></ul></ul><ul><ul><li>Definitive host – organism that harbor the adult, sexually mature form of parasite </li></ul></ul>
    36. 36. Life cycle of Plasmodium in humans <ul><li>Humans – intermediate hosts, asexual reproduction takes place </li></ul><ul><ul><li>Liver – mosquito bite infects human w/ sporozoites wh/ travel thru the blood into the liver </li></ul></ul><ul><ul><ul><li>Sporozoites are removed from the blood and enter the liver cells </li></ul></ul></ul><ul><ul><ul><li>They undergo asexual reproduction or schizogony to form 1000s of merozoites </li></ul></ul></ul>
    37. 37. Life cycle of Plasmodium in humans <ul><li>Humans </li></ul><ul><ul><li>Merozoites leave the liver to infect RBCs </li></ul></ul><ul><ul><li>RBCs </li></ul></ul><ul><ul><ul><li>Merozoites infect and reproduce in RBCs </li></ul></ul></ul><ul><ul><ul><li>The RBCs then rupture and release merozoites which infect more RBCs </li></ul></ul></ul><ul><ul><ul><ul><li>Their waste products cause the fever and chills characteristic of malaria when RBCs rupture </li></ul></ul></ul></ul><ul><ul><ul><li>Some merozoites develop into gametocytes (male, female) </li></ul></ul></ul>
    38. 38. Life cycle of Plasmodium in Mosquitos <ul><li>Mosquitos – definitive hosts , sexual reproduction takes place </li></ul><ul><ul><li>Mosquito picks up gametocyte when bite infected human </li></ul></ul><ul><ul><ul><li>Gametocyte travel to mosquito intestine and begin sexual cycle </li></ul></ul></ul><ul><ul><ul><li>Gametocytes unite to form a zygote wh/ forms an oocyst where sporozoites are formed </li></ul></ul></ul><ul><ul><li>Sporozoites migrate to the mosquito salivary glands where they are transmitted to human’s blood w/ the next bite </li></ul></ul>
    39. 39. Apicomplexa continued <ul><li>Cryptosporidium – causes intestinal infection </li></ul><ul><ul><li>Transmission is by feces, H2O, nosocomial infections </li></ul></ul><ul><li>Toxoplasma gondii </li></ul><ul><ul><li>Intracellular parasite - causes toxoplasmosis </li></ul></ul><ul><ul><li>Transmitted through cat feces and is dangerous for pregnant women </li></ul></ul><ul><ul><ul><li>Can cause problems in fetus including stillbirth </li></ul></ul></ul>
    40. 40. Medically important Protozoan Phyla <ul><li>Ciliophora – ciliates, cilia for movement and to bring food into mouth </li></ul><ul><ul><li>Balantidium coli – only ciliate that is a human parasite </li></ul></ul><ul><ul><ul><li>Cause severe dysentery </li></ul></ul></ul><ul><ul><ul><li>Cysts excreted in feces </li></ul></ul></ul><ul><li>Euglenozoa – 2 groups </li></ul><ul><ul><li>Euglenoids </li></ul></ul><ul><ul><ul><li>photoautotrophs </li></ul></ul></ul>
    41. 41. Phylum Euglenozoa <ul><li>Euglenoids cont. </li></ul><ul><ul><li>Pellicle = semi-rigid plasma membrane </li></ul></ul><ul><ul><li>Anterior flagella, red eyespot that senses light </li></ul></ul><ul><li>Hemoflagellates –blood parasites transmitted by bites of blood feeding insects </li></ul><ul><ul><li>Have a long slender body and undulating membrane </li></ul></ul><ul><ul><li>Trypanosoma brucei gambiense – causes African sleeping sickness from bite of tse tse fly </li></ul></ul><ul><ul><li>Trypanosoma cruzi – causes Chagas’ disease – bite of kissing bug (face) – trypanosome in feces wh/ gets in bite </li></ul></ul>
    42. 42. Helminths – parasitic worms <ul><li>Phylum Platyhelminthes = flatworms </li></ul><ul><ul><li>2 groups = trematodes and cestodes </li></ul></ul><ul><li>Trematodes = flukes </li></ul><ul><ul><li>Flat, leaf shaped bodies, suckers to hold them in place, </li></ul></ul><ul><ul><li>Paragonimus westermani – lung fluke pg 373 life cycle </li></ul></ul><ul><ul><ul><li>Adult lives in bronchioles of mammals where hermaphroditic adults lay eggs into the bronchi </li></ul></ul></ul>
    43. 43. Helminths – parasitic worms <ul><li>Paragonimus westermani cont . </li></ul><ul><ul><li>Sputum w/ eggs is coughed up, swallowed, and excreted w/ feces </li></ul></ul><ul><ul><li>Eggs have to make it to H2O to find intermediate hosts (snail, crayfish) </li></ul></ul><ul><ul><li>Transmission – ingestion of undercooked crayfish </li></ul></ul><ul><ul><li>Dx –eggs in sputum or feces </li></ul></ul>
    44. 44. Helminths – parasitic worms <ul><li>Cestodes = tapeworms </li></ul><ul><ul><li>Lack a digestive tract, absorb nutrients thru cuticle </li></ul></ul><ul><ul><li>Scolex = head with suckers and hooks for attachment </li></ul></ul><ul><ul><li>Proglottids = body segments wh/ are produced by neck of scolex </li></ul></ul><ul><ul><ul><li>Mature proglottids contain both male and female reproductive organs </li></ul></ul></ul><ul><ul><ul><li>Those farthest from scolex are bags of eggs </li></ul></ul></ul>
    45. 45. Cestodes = tapeworms <ul><li>Humans as definitive hosts </li></ul><ul><ul><li>Taenia saginata – beef tapeworm </li></ul></ul><ul><ul><ul><li>Proglottids ingested by grazing animals </li></ul></ul></ul><ul><ul><ul><li>Larvae migrate to muscle (meat) where they encyst as cysticerci </li></ul></ul></ul><ul><ul><ul><li>If you eat infected meat all but the scolex is digested </li></ul></ul></ul><ul><ul><ul><ul><li>It anchors itself to the small intestine and starts producing proglottids </li></ul></ul></ul></ul>
    46. 46. Cestodes = tapeworms <ul><li>Humans as definitive hosts cont. </li></ul><ul><ul><li>Taenia solium = pork tapeworm </li></ul></ul><ul><ul><ul><li>Adult worms in human intestines lay eggs that pass out w/ feces and are eaten by pigs </li></ul></ul></ul><ul><ul><ul><li>Eggs hatch into larvae wh/ encyst in pigs muscles </li></ul></ul></ul><ul><ul><ul><li>Transmission by eating undercooked pork – not in US </li></ul></ul></ul><ul><ul><ul><ul><li>Human-going in larvae-in adult- leaving eggs </li></ul></ul></ul></ul><ul><ul><ul><li>Eggs shed by 1 person and ingested by another – eggs hatch and encyst in brain and other body parts causing cysticercosis – now human intermediate host </li></ul></ul></ul><ul><ul><ul><ul><li>Human – eggs leaving – human eggs ingested – larvae hatch and encyst </li></ul></ul></ul></ul>
    47. 47. Tapeworm Life Cycle
    48. 48. Cestodes = tapeworms <ul><li>Humans as intermediate hosts pg 375 </li></ul><ul><ul><li>Echinococcus granulosus = dog tapeworm </li></ul></ul><ul><ul><ul><li>Dogs, coyotes – definitive hosts </li></ul></ul></ul><ul><ul><ul><li>Eggs transmitted by dog feces or saliva after dog licks self </li></ul></ul></ul><ul><ul><ul><li>Eggs hatch in the small intestine and larvae migrate to liver or lungs </li></ul></ul></ul><ul><ul><ul><li>Larvae develop into hydatid cyst wh/ contain brood capsules wh/ can produce 1000s of scoleces </li></ul></ul></ul><ul><ul><ul><li>Sx = abdominal and chest pain, coughing up blood </li></ul></ul></ul>
    49. 49. Nematoda = roundworms <ul><li>Free-living and parasitic </li></ul><ul><li>Cylindrical, tapered at each end </li></ul><ul><li>Complete digestive system </li></ul><ul><li>Most are dioecious (male and females) – males are smaller than females and have spicules on posterior end to guide sperm into female genital pore </li></ul><ul><li>Human infection can be divided into whether the egg or larvae is infective </li></ul>
    50. 50. Nematode eggs infective for humans <ul><li>Enterobius vermicularis = pinworm </li></ul><ul><ul><li>Spends entire life in humans </li></ul></ul><ul><ul><li>Adults in large intestine </li></ul></ul><ul><ul><li>Female migrates to anus to lay eggs on perianal skin </li></ul></ul><ul><ul><li>Eggs ingested by the same host or another person thru contaminated bedding or clothes </li></ul></ul><ul><ul><li>Dx. Graham sticky-tape method </li></ul></ul>
    51. 51. Pinworm Life Cycle
    52. 52. Pinworms on Perianal Folds
    53. 53. Nematode eggs infective for humans <ul><li>Ascaris lumbricoides – large (30 cm), infects over 1 billion ww </li></ul><ul><ul><li>Dioecious w/ sexual dimorphism = male and female different </li></ul></ul><ul><ul><ul><li>Male smaller w/ curled tail </li></ul></ul></ul><ul><ul><li>Adults live in small intestine of humans only </li></ul></ul><ul><ul><li>Feed on semi-digested food </li></ul></ul><ul><ul><li>Eggs excreted in feces > ingested by another host > hatch in sm intestine > burrow out of intestine and enter blood where they are carried to the lungs to grow > coughed up and swallowed and return to the Small Intestine to mature into adults (now can repro) </li></ul></ul>
    54. 54. Nematode larvae infective for humans <ul><li>Necator americanus, Ancylostoma duodenale = adult hookworms that live in the small intestine of humans </li></ul><ul><ul><li>eggs are excreted in feces </li></ul></ul><ul><ul><li>Larvae hatch in soil where they enter host by penetrating skin </li></ul></ul><ul><ul><li>Larvae enter blood or lymph vessels and are carried to lungs > coughed up in sputum > swallowed and carried to small intestine </li></ul></ul><ul><ul><li>Dx by eggs in feces, avoid by wearing shoes </li></ul></ul>
    55. 55. Nematode larvae infective for humans <ul><li>Trichinella spiralis – causes trichinellosis by eating undercooked pork or game animals (bear) w/ larval cysts in ms </li></ul><ul><ul><li>Larvae are freed from cysts in small intestine > mature into adults > sexually reproduce > females give birth to live larvae wh/ enter lymph and BVs > they migrate to ms and other tissue where they encyst and remain until eaten by another host </li></ul></ul><ul><ul><li>Dx = microscopic exam of larvae in ms biopsy </li></ul></ul><ul><ul><li>Prevention = cook meat </li></ul></ul>
    56. 56. Arthropods = Insects, Arachnids <ul><li>Have segmented bodies, hard external skeletons, jointed legs </li></ul><ul><li>If carry pathogenic microorganisms = vectors table on pg 378 </li></ul><ul><ul><li>Mechanical vectors transport pathogens on feet or body ex. Flies </li></ul></ul><ul><ul><li>Biological vectors - pathogens multiply in vectors and are transmitted thru saliva or feces </li></ul></ul>
    57. 57. Body & Crab Lice
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