Parasitology Lec 4: Selected Protista

the clade diplomonada lacks

mitochondria

*know! a member of the clade diplomonada that is a parasite of human digestive tract

Giardia lamblia

Giardia is passed along through _____ and causes _____

contaminated water; gastrointestinal illness

Giardia lamblia now occurs in all waters in the ____. It can be spread by ____besides humans

U.S.; other mammals

example: it can be spread by

beaver urine

even “pristine waters” high in the ____ now have Giardia lamblia

Rocky Mtns

it is controlled in drinking water by

filtering and adding chlorine

Phylum Apicomplexa (Spoeozoa) defining character

an apical complex

what does an apical complex aid in

the penetration of the host’s cell

an apical complex consists of

microtubules and rhopteries

what does rhopteries release

enzymes

class coccidea contains

parasites of both vertebrates and invertebrates

class coccidea are considered

non-motile

how many members of the Plasmodium genus cause malaria

four

what is the most deadly of the four

P. falciparum

what is the most important infectious disease of humans

malaria

the distribution is in what areas and at least how many people live in these areas and they are at risk

tropical and subtropical regions; at least 1 billion people

how many people become seriously ill with malaria each year

300-500 million people

resulting in how many deaths each year

1-2 million

*know! female mosquitoes (Genus _____) are the vectors

Anopheles

the female mosquitoes must ingest blood from hosts continuously to

nourish their developing embryos

pladmodium life cycle (essay question btw): dormant ____ gametophytes occur within the red blood cells of their human host and are _______by the mosquito

haploid; ingested

this is the only stage of the Plasmodium that can

infect the female mosquito

within the mosquito, the gametophytes mature into either

male or female gametes

the female gametes are then fertilized by the

male gametes

the motile, diploid zygotes move to the mosquito’s stomach and

encyst in the stomach’s wall

each encysted zygote (oocyst) undergoes meiosis so that

there are two haploid cells within the cyst

these haploid cells undergo what

multiple fission within the cyst

Multiple fission:

the nucleus of the cell undergoes many mitotic divisions, producing a number of nuclei. After the nuclear divisions are complete, the cytoplasm separates, and each nucleus becomes encased in its own membrane to form an individual cell.

one cyst can produce up to

10,000 haploid cells

these haploid cells mature into what

sporozoites. the sporozoites break out of the oocyst and migrate to the insect’s salivary gland where they are injected into a human host as the mosquito feeds.

the sporozoites migrate to ___

the liver and invade the liver cells

the sporozoite then becomes a

cyst

This cyst then undergoes multiple fission known as what to produce what

shizogony; numerous merozoites

merozoites rupture the liver cell they are in and enter

the bloodstream

the merozoites then immediately invade the

red blood cells

some merozoites that enter red blood cells from gametophytes that can be taken by the

mosquitoes

other merozoites that enter red blood cells undergo multiple fission (shizogony) to form what

more merozoites that rupture the red blood cell and then invade more red blood cells

the fever and chills characterizing malarial infections result from

toxins released during the synchronous of the infected red blood cells

the ruptures occurs every

48 hours

there are a number of potential control strategies for controlling malaria but so far none of these have become ____ in their use

practical

many advocate for greater use of

DDT

DDT has environmental consequences bcuz mosquitoes have developed

resistance to DDT

Sleeping under a mosquito net treated with ____ is currently the most effective way of controlling malaria

pyrethroids

what is a particularly widespread and common parasite of mammals and birds

toxoplasmosis gondii

the definitive host for toxoplasmosis is the

domestic cat

*know! Definitive host:

A host in which the sexual reproduction of a parasite occurs. if no sexual reproduction occurs in the host, the definitive host is the host where the parasite reaches maturity.

most of the lifecycle of Toxoplasma gondii is similar to other members of what and mostly occurs where

Coccidea; in the intestines of cats

the ___ are expelled with the cat’s feces

oocysts

what develop within the oocysts

sporozoites

when rodents, humans, many other mammals and birds ingest the oocysts, the sporozoites break out and

cross from the intestine to a variety of tissues

the host’s immune system responds and the sporozoites become tough tissue cysts called

bradyzoites

the bradyzoites are infective to cats that eat

infected prey

humans can be infected by

eating undercooked infected meat

most infected adult humans have no symptoms because

Toxoplasma gondii is held in check by our immune systems

however, for ____patients there can be serious complications in the brain

AIDS

infection in the ____ trimester of a human fetus can increase the chances of mental retardation

first

in cryptosporidium parvum, the oocyst is excreted in

urine or feces

*know! the oocyst is ____ to environmental factors

very resistant

what develop within the oocyst

sporozoites

the oocyst is ingested while

a mammal drinks water

the rest of the life cycle occurs where

in the small intestine

it causes

severe gastrointestinal illness (worse than Giardia)

often results in death for ____ patients

AIDS

cryptosporidium parvum can be found in

contaminated drinking water

filtration helps, but is highly resistant to

chlorine and other disinfection practices

*adding additional chlorine can result in what (know!)

trihalomethanes and haloacetic acid

both of these can cause

cancer

Phylum Euglenozoa has a

Pellicle: a thin secreted envelope that covers the organism

they also have ____ and repro by

flagellates; binary fission

subphylum kinetoplasta was formerly in the

Zooflagellates

they are characterized by

a single, large mitochondrion containing a kinetoplast

the kinetoplast contains

extra-nuclear DNA

many are _____ and belong to the genus _____ which inhabit the blood of vertebrates

parasitic; Trypanosoma

what causes african sleeping sickness

Trypanosoma brucei

what are the symptoms of african sleeping sickness

fever, swelling, headache, weakness, enters the CNS and leads to apathy, mental dullness, lack of coordination, death

Trypansomoa cruzi causes

Chagas’ disease in humans in central and south america

it is transmitted by what

“kissing bugs”, a name arising from the bug’s habit of biting its sleeping victim on the face

Chagas Disease seldom

kills its victims directly

It produces symptoms of

chronic lethargy, irritability, and increased susceptibility to other diseases

combined with ____ it lowers life expectancy and increase human suffering

poor nutrition and other diseases

infects more than ____ in central and south america

20 million

Phylum Parabasala- most are

mutalistic symbionts

they have prominent ___ and up to a _____ flagella

Golgi bodies; thousand

example:

Trichonympha- found in the guts of terminates

bacteria in Trichonympha breaks down

the wood (cellulose) that termites feed on