exam 4

Algology, Parasitology, and Mycology- Ch 12 & 20

are protozoa unicellular or multicellular parasites?

unicellular parasites

do protozoa have photosynthetic abilities?

No, they lack photosynthetic capabilities

Are protozoa motile or non-motile?

motile, at some stage in their life cycle

how to protozoa reproduce?

most often reproduce by asexual fission

are protozoa heterotrophic or autotrophic?

heterotrophic

how are protozoa classified?

protozoa are grouped according to their mode of locomotion

what modes of locomotion do protozoa bear?

• flagella

• pseudopodia

• cilia

• polar filaments

what mode of locomotion do Subphylum Mastigophora bear and what are some examples?

Subphylum Mastigophora are flagellated

• Giardia lamblia, Leishmania species, Trichomonas
  vaginalis, Trypanosoma brucei rhodesiense, and
  Trypanosoma brucei gambiense, Trypanosoma cruzi

how do subphylum Sarcodina move?

move by means of pseudopodia

• Entamoeba histolitica

what disease does Entamoeba histolitica cause and what are the symptoms?

causes Amebiasis, an intestinal (bowel) illness transmitted by human feces that can present diarrhea, nausea, stomach pain/discomfort/cramping, and weight loss

how do you treat Entamoeba histolitica?

metronidazole and/or tinidazole and staying hydrated

how do phylum Ciliophora move?

move by means of cilia, entirely covering the organism

where is Ciliophora commonly found?

found near the oral cavity

what does the cilia in Ciliophora assist in?

helps propel food into opening (cytosome)

Ciliophora example

Balantidium coli

what disease/disorder does Balantidium coli cause?

causes ulcers in large intestine

how do phylum Apicomplexa (sporozoa) move?

move by means of flagella

what organisms are included in Apicomplexa (Sporozoa)?

• Plasmodium species

• Toxoplasma gondii

• Cryptosporidium parvum

what disease/disorder does Plasmodium species cause?

Malaria

malaria transmission + symptoms + treatment

• transmitted through female mosquitoes.

• symptoms include fever and flu like symptoms. nausea, vomiting, anemia, jaundice and diarrhea may also occur.

• treated with;

  • artemether-lumefantrine

  • atovaquone-proguanil

  • quinine

  • mefloquine

what disease/disorder does Toxoplasma gondii cause?

Toxoplasmosis

toxoplasmosis transmission + symptoms + treatment

• transmitted from consumption of undercooked meat, cat feces or mother-baby

• those infected are typically asymptomatic but symptoms include fever, swollen glands, muscle aches, and fatigue

• treated w/ pyrimethamine and sulfadiazine, + folinic acid

what disease/disorder does Cryptosporidium parvum cause?

Cryptosporidiosis

cryptosporidiosis transmission + symptoms + treatment

• transmitted through coming in contact with fecal contaminated water/food

• symptoms include diarrhea, nausea, vomiting, stomach pain/discomfort/cramping, fever and weight loss

• normally resolved on its own but nitazoxanide can be used to treat diarrhea caused by this

how do phylum Microspora move?

move by means of polar filaments

what disease/disorder does Microspora cause?

Microsporidium (diarrhea)

microsporidium transmission + symptoms + treatment

• transmitted via ingestion, inhalation, direct contact with the conjunctiva/spores, animal contact, or person-to-person transmission.

• symptoms include diarrhea, muscle aches/fatigue, keratitis and bronchitis

• treated w/ albendazole or fumagillin, topical fumagillin and oral albendazole for eye disease

where are protozoa found?

majority are free living and can be found in marine, fresh water and terrestrial habitats

can protozoa be parasitic? if so, what is the host range?

yes, host range: algae-humans

protozoa are essential ____

decomposers

what environmental factor do protozoa require large amounts of?

moisture

why are protozoa an important part of the food chain?

b/c they consume bacteria and serve as food for larger species. they help maintain ecological balance in soil and decrease sewage solids

protozoa structure characteristics (cell wall, cell structures)

• protozoa lack cell wall, shape is determined by the material beneath the plasma membrane

• they have membrane bound nucleus and contain organelles, but they lack chloroplasts because they are not photosynthetic organisms

• they have specialized structures for movement

how to protozoa ‘eat’

food, water and O₂ diffuse through the cell membrane or through pinocytosis/phagocytosis

to reproduce, protozoa require more than one ____

habitat or host

protozoa are polymorphic, what does that mean?

that they can be found in distinct forms throughout the different stages of their life cycle

protozoa can exist as trophozoites or cysts, what does that mean?

• trophozoites is the vegetative/feeding form

• cysts are the resting/infectious form found when they encounter certain environmental conditions

what are certain environmental conditions that cause protozoa to rest/go into cyst form?

lack of nutrients, moisture, oxygen, etc.

do protozoa reproduce asexually or sexually?

both are common, can occur individually or both

protozoa + binary fission

DNA replication followed by division of 2 cells, longitudinally (flagellates) or transversely (ciliates)

how are protozoa classified if they contain both flagella and cilia?

by the method of replication

protozoa + multiple fissions (schizogony)

multiple DNA divisions resulting in a cell w/ many single celled organisms

how are Leishmaniasis carried?

they are zoonotic protozoa carried by rodents, dogs and foxes and they are transmitted to humans by a sandfly bite

what cells do promastigotes invade and transform into?

it is the flagellated (motile) form that invade phagocytic cells (macrophages) and transform into non-motile, amastigote

where do amastigotes multiply

in phagocytic cells found in the lymph node, spleen, liver and bone marrow (reticuloendothelial system)

Cutaneous Leishmaniasis

include L. tropica and L. mexicana

• causes skin ulcers that develop at the site of bite due to the skin being destroyed after the activation of cell mediated immunity, ulcer takes ~ a yr to heal

Cutaneous Leishmaniasis diffusion

nodular lesions diffuse across the body due to inactive CMI response, untreated infections can last years

Mucocutaneous Leishmaniasis

include L. braziliensis

• dermal ulcerations that initially heal. but ulcers appear in the mucous membrane of the nose/mouth that may erode nasal septum, soft palate and lips if left untreated

Visceral Leishmaniasis -Kala-azar

includes L. donovani

• an often fatal condition common in young, malnourished children that causes fever, anorexia, weight loss, abdominal swelling (from hepatomegaly) and spleen (splenomegaly) due to the invasion of fixed reticuloendothelial cells (fixed phagocytic cells) of these organs

african sleeping sickness transmission + initial symptoms

• following bite, trypomastigote (flagellated motile form) spreads in the bloodstream to the lymph nodes + CNS.

• initial painful skin ulcers heal w/n 2 weeks followed by fever, headache, dizziness and lymph node swelling (due to systemic spread). fevers are intermittent due to variable surface glycoproteins (VSG)

african sleeping sickness CNS symptoms

daytime drowsiness (hence the name), slurred speech, difficulties walking, coma, death

two forms of african sleeping sickness

• west african sleeping sickness (Trypanosoma brucei gambiense): slowly progressing symptoms

• east african sleeping sickness (Trypanosoma brucei rhodesiense): more severe, death occurs w/n weeks

chaga’s disease transmission + symptoms

Trypanosoma cruzi

• Trypomastigotes tunnel into human host and transform into amastigote that invades skin, macrophages, lymph nodes and spreads through the bloodstream

• hard, red area develops at the site of entry followed by systemic spread w/ fever, malaise + swollen lymph nodes, includes heart and CNS

chaga’s disease phases

• acute phase: fever, malaise, swollen lymph nodes, meningoencephalitis, acute myocarditis (resolves ~ a month)

• intermediate phase: low levels of parasites in blood and ⊕ antibody response, but NO symptoms (most cases remain here for life)

• chronic phase: target organs affected; heart, colon & esophagus- dementia, megacolon, megaesophagus, heart damage + failure

what are the # of global cases and mortality stats of malaria per year?

~ 200 million global cases and > 1 million deaths

what follows paroxysms in malaria? what causes this?

the periodic episodes of high fever and shaky chills are followed by periods of profuse sweating, caused by the bursting of RBC and release of merozoites

Toxoplasma gondii life cycle/phases

• Intestinal: only in cats

• extraintestinal: occurs in all infected animals

transmission of toxoplasma gondii

occurs via oocysts (cat feces) or bradyzoites (raw/undercooked meat)

• transplacental transmission is possible: spontaneous abortion, still birth, child born w/ mental/physical delays, blindness

what are some recommendations for pregnant women to avoid toxoplasmosis

• avoid contact with cats and do not empty cat’s litter boxes

• avoid consuming raw/undercooked meat

what issues may immunocompromised individuals face if infected with toxoplasmosis?

toxoplasma encephalitis

what disease does Giardia lamblia (Mastigophora) cause?

giardiasis, an intestinal/luminal protozoa

giardiasis symptoms + treatment

• a non-bloody, foul smelling diarrheal disease that can cause nausea, anorexia, flatulence, stomach/abdominal pain and discomfort and weight loss

• treatment includes metronidazole, tinidazole, and nitazoxanide. other medications include paromomycin, quinacrine, and furazolidone

what is the transmission of Giardia lamblia?

ingesting cysts in fecally contaminated food and water, contaminated streams, day care centers, mental hospitals

does chlorine kill Giardia lamblia? if not, what does?

no, only boiling and filtration

what are some clinical findings of Giardia lamblia?

trophozoites adhere to the wall of the small intestine by sucking disk and interferes w/ fat absorption.

Cryptospridium parvum/hominis transmission

via ingestion of oocysts in fecally contaminated water

• agricultural runoff- zoonosis

Cryptospridium parvum/hominis symptoms

causes short term, mild diarrhea

• chronic watery diarrhea in immune compromised individuals (AIDS pts)

Entamoeba histolytica symptoms

• diarrhea ranging from mild asymptomatic to severe dysentery

• may invade intestinal mucosa, causing erosions (10%)

• may penetrate blood circulation, causing abscesses in liver and lungs, often resulting in death (100,000 deaths worldwide)

Trichomonas vaginalis transmission

a sexually transmitted disease infecting the female vagina and male urethra via trophozoite (no cyst stage)

Trichomoniasis symptoms

• most males are asymptomatic

• women may also be asymptomatic but typically present itching, burning with urination, and white, frothy, malodorous discharge- highly motile trophozoites may be visible in discharge

Trichomoniasis treatment

treated w/ metronidazole, males are also treated to prevent re-infection of female partner

Naegleria fowleri habitats

a free living amoeba living in fresh water (lakes), soil, thermal discharges of power plants, heated swimming pools (not chlorinated), aquariums and sewage

Naegleria fowleri transmission

infection occurs when the organism enters the body through the nose, where it tracels to the brain/spinal cord and destroys the tissue

Naegleria fowleri causes what disease

primary amebic meningoencephalitis (PAM), a brain inflammation that leads to the destruction of brain/spinal cord tissue and fatal (survival rate: < 1%)

Naegleria fowleri symptoms

pts present fever, headache, stiff neck, nausea, vomiting

Acanthamoeba habitat

the microscopic free living amoeba lives in fresh water lakes, coil, air, sewers and drinking water systems

Acanthamoeba transmission

can be acquired from swimming in contaminated water, HVAC systems, shower heads, taps, etc

Acanthamoeba keratitis targets what body part

eyes; typically occurs in healthy individuals and can result in permanent visual impairment/blindness

(Acanthamoeba) Granulomatous Amebic Encephalitis (GAE) targets what body part/system

infection of the brain + spinal cord that typically occurs in immunocompromised individuals

what is a disseminated infection

widespread infection that can affect the skin, sinuses, lungs, and other organs independently or simultaneously. common in immunocompromised individuals

arthropods as vectors (mechanical)

involves mechanically transporting a microbe from one place to another (microbe carried on fly’s leg)

arthropods as vectors (biological)

essential part of life cycle, pathogen can multiply within the vector (like Leishmania and Plasmodium inside sand fly, and Anopheles sp. in mosquitoes)

how do mosquitoes transmit diseases and pathogens

by inserting its feeding tube through the host’s skin. it ingests blood and pick up infectious agents, transferring them to subsequent hosts

ex: malaria, yellow fever, dengue fever, west nile encephalitis

how do fleas transmit diseases/pathogens

fleas pick up bacterium when biting infected host, where the bacterium multiplies and blocks the digestive tract. starving fleas bite repeatedly, passing pathogen to new host. fleas can live in dormant stage for months and mature quickly + jump

what is an example of a disease fleas transmit

yersinia pestis

how do lice transmit diseases/pathogens

the small, wingless insect sucks blood through the skin w/ appendages adapted for attachment. head lice do not transmit disease

pediculus humanus

lice that easily spreads by direct contact or through contact w/ personal items. survives only a few days w/o host

body lice transmits _____

bacterial diseases; trench fever (Bartonella quintana), epidemic typhus (Rickettsia prowazekii), relapsing fever (Borrelia recurrentis)

Dermacentor andersoni transmits ______

wood tick that transmits rocky mounted spotted fever (Rickettsia rickettsii)

Ixodes scapularis transmits ______

lyme disease (Borrelia burgdorferi)

what can the saliva in ticks cause?

paralysis, especially in children, recovery follows removal

what diseases/pathogens do mites transmit?

the tiny, small moving arachnids do not transmit diseases but can trigger asthma and cause itching

mite habitats

live on the outer surfaces of plants and animals. Demodex live unnoticed in hair follicles or oil producing glands. large numbers also live indoors and feed on shed skin cells

what to chiggers cause

cause intense itching when they attach and feed on fluids within the skin

Sarcoptes scabiei mites transmission + disease

cause scabies and transmitted via personal contact

are helminths unicellular or multicellular?

multicellular parasites

name the 3 classes of helminths

1. nematodes/roundworms

2. cestodes/tapeworms

3. trematodes/flukes

how do helminths cause disease? entry routes?

they invade host tissue or deprive the body of nutrients and have multiple routes of entry

the what is helminth life cycle like

they have complex life cycles with intermediate hosts (1+) during the early stages of development and then a definitive host where their sexually mature form takes place