subkingdom: protozoa (“first animal”) kingdom: protista 1

SUBKINGDOM: PROTOZOA (“FIRST ANIMAL”)

KINGDOM: PROTISTA1

Reminder

Your group project plates have to be inoculated this Thursday or else wait until after the holiday break.

If you inoculate this Thursday, you need to go and observe them this Saturday.

Remember to bring a good quality camera for photos that you might want to blow up and put on your poster. Cell phones don’t have good quality for this.

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CHARACTERISTICS OF PROTOZOA

1. Unicellular 2. Chemoheterotrophs (get their energy by breaking down

organic matter). 3. Most ingest their food; thus, they have special

structures for this. 4. Trophozoites: any stage in a protozoa’s life cycle which can

ingest food. In practice it refers to the motile form (pseudopods, cilia, flagella).

5. Cyst: Non-motile form, protected by a membrane. This is usually the infective stage. Cysts have a thick cell wall that allows for survival in harsh environments better than the trophozoite form. Excystation: process of emergence of the trophozoite from the cyst.

7. Capable of reproductionA. Asexual: fission, budding, or schizogony

(produces a large number of trophozoites)B. Sexual: conjugation

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PROTOZOA CYSTS

Cysts are not as resistant as a bacterial endospore.

You can kill cysts by boiling them. They can live in the soil or water for

months.A cyst is not motile, so it is not trophozoic. A cyst does not go and seek its nutrients or

ingest food, but it can absorb nutrients. It has no organelles to ingest food.

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ClassificationDomain: Eukaryotes

Kingdom: Protista

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TERMS: Host Types

The definitive host is the one in which the parasite completes its sexual life cycle.

For instance, in Plasmodium, the definitive host is the tropical mosquito anopheles and the intermediate host is the human.

Some organisms use the human as the definitive host.

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Mosquito7

Kingdom ProtistaSubkingdom: Protozoa

Phylum: Sarcomastigophora Subphylum: Sarcodina (amoebas)

Amoeba spp. Entamoeba histolytica Naegleria fowleri

Subphylum: Mastigophora (flagellates) Giardia lamblia Trichomonas vaginalis Trypanosoma brucei and cruzi

Phylum: Ciliata (ciliates) Paramecium spp Balandtidium coli

Phylum: Apicomplexia (Sporozoa; non-motile obligate parasites) Plasmodium spp Toxoplasma gondii Cryptosporidium

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Phylum: Sarcomastigophora(amoebas and flagellates)

Amoebas (move by pseudopods) Flagellates (move by flagella)

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Subphylum: Sarcodina (amoebas)

All amoebas have pseudopods (false foot)Amoeba spp (free living; not parasitic)Entamoeba histolytica (parasitic)Naegleria fowleri (parasitic)

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AmoebaPseudopodsPseudopods

NucleusNucleus

Food vacuoleFood vacuole11

Amoeba

p

PseudopodsPseudopods

NucleusNucleus


AmoebaPseudopodsPseudopods

NucleusNucleus


Entamoeba histolytica

Disease: AmoebiasisThis is a global disease that any traveler can get.

As soon as you cross the border into Mexico, you are exposed to it.

Entamoeba histolytica consume red blood cells.

In a fresh diarrheal specimen, you can see RBCs in the cytoplasm of the amoebas.

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Entamoeba histolytica, as its name suggests, can actually bore through the enteric walls (histolysis = destroying tissue) and reach the blood stream.

From there, it can reach different vital organs of the human body, like the liver, lungs, brain, eyes etc.

A typical effect is a liver abscess caused by such migrating Entamoeba histolytica, which can be fatal.

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Entamoeba histolytica infection can lead to amoebiasis or amoebic dysentery. Symptoms include dysentery (diarrhea), weight loss, fatigue, and abdominal pain.

It can be diagnosed by stool samples. Trophozoites should be seen in a fresh fecal smear and cysts in an ordinary stool sample.

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Treatment Metronidazole

Diagnostic Features Ingested RBC Bull’s eye Karyosome

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Entamoeba histolyticaTrophozoites

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Trophozoites of Entamoeba histolytica with ingested erythrocytes

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Cysts

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Entamoeba

histolytica

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Teen nearly blinded after parasite latches onto contact lens

A rare parasite had grown on her contact lens and was trying to eat its way through her cornea. Had they not discovered it in time, Ashley could have lost the use of her eyesight.

Ashley had what is called an acanthamoeba infection. A tiny parasite, commonly found in fresh water and soil, acanthamoeba are capable of spreading through contact lens infections, cuts or being inhaled into the lungs.

Acanthamoeba infections are just one possible side effect of improper cleaning of contact lenses. Many ophthalmologists recommend using daily disposable contact lenses, to better avoid contracting infection and disease.

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Naegleria fowleri

“Brain-eating amoeba“Found in the soil and in freshwater lakes in the

Southern part of the United States during the summer.

Infections usually occur when it is hot for prolonged periods of time

It can also survive in inadequately chlorinated swimming pools or dirty tap water, and can infect the brain when someone gets water up the nose.

Causes primary amoebic meningoencephalitis (PAM)

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Naegleria fowleri

Boy, 9, Dies of Rare Amoeba Infection After Swimming in a Lake

http://shine.yahoo.com/parenting/boy-9-dies-rare-amoeba-infection-swimming-lake-182700398.html

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Girl contracts brain eating amoeba after swimming at Arkansas water park. July 29, 2013

A 12-year-old Arkansas girl has contracted parasitic meningitis, a rare and deadly disease caused by a brain-eating amoeba, Naegleria fowleri, typically found in freshwater or soil. It enters the human body through the nose, where it then moves to the brain, typically causing death.

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"I couldn't get her fever down. She started vomiting," Hardig told the Christian Post. "She'd say her head hurt really bad. She cried, and she would just look at me and her eyes would just kind of roll."Doctors put Kali into a coma, in order to stabilize her condition.







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Subphylum: Mastigophora (Flagellates)

Giardia lamblia (intestinal parasite) Trichomonas vaginalis (urogenital parasite) Trypanosoma brucei and cruzi (blood parasite)

Undulating membrane (for movement) Kinetoplast (circular mass of DNA)

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Mastigophora: Flagellates

Giardia lambliaDisease: Giardosis

Trichomonas vaginalisDisease: Trichomoniasis (an STD)

Trypanosoma bruceiDisease: African Trypanosomiasis

• African Sleeping Sickness Trypanosoma cruzi

Disease: American Trypanosomiasis• Chaga’s disease

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TERMS

Mastigote = flagellaPromastigote: has single flagellaAmastigote: has no flagellaKinetoplast: round mass of circular DNA

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Giardia lamblia

Disease: Giardosis Cysts are resistant forms and are

responsible for transmission of giardiasis. Both cysts and trophozoites can be found in

the feces. Infection occurs by the ingestion of cysts in

contaminated water, food (includes undercooked meat), or by the fecal-oral route.

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Life Cycle of Giardia lamblia

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Giardia lamblia

Trophozoite form: piroform (pear or teardrop shape), looks like a happy face.

Discovered by Anton Van Leuwenhoek when he examined his own feces when he had this infection.

You won’t see the flagella in lab because you need a special stain for that.

Cyst form: oval shaped. Nuclei looks like two eyes.

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Giardia lamblia

Trophozoite

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Giardia lamblia

Trophozoites

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Giardia lamblia

Trophozoites

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Giardia lamblia trophozoite

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Giardia lamblia

Cysts

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Giardosis

Abdominal painDiarrheaGas or bloatingHeadacheLoss of appetiteLow-grade feverNauseaSwollen or distended abdomenVomiting

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Trichomonas vaginalis

Disease: Trichomoniasis Trichomonas vaginalis resides in the female

lower genital tract and the male urethra and prostate.

The parasite is a trophozoite only; it does not have a cyst form, and does not survive well in the external environment.

Trichomonas vaginalis is transmitted among humans, its only known host, primarily by sexual intercourse.

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40


Trophozoite

Undulating membrane

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Trichomonas vaginalis 42

Trichomoniasis

Usually asymptomatic in men, or mild itchingIn women, vagina is extremely pruritic, with

vaginal odor and discharge.

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Trypanosomiasis

African Trypanosomiasis (African Sleeping Sickness)

American Trypanosomiasis (Chaga’s Disease)

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Trypanosoma brucei

Disease: African Trypanosomiasis“African Sleeping Sickness”

Trypanosomiasis has a biological vector, the tsetse (pronounced “set-see”) fly.

Wild animals may also be a reservoir (Zoonotic is when a disease is transmitted to animals as well as humans.)

The tsetse fly bites a human and injects the trypanomastigotes into the skin.

This causes a chancre (pronounced “shanker”), which is an ulcer on the skin.

Then it enters the lymphatic system.

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Trypanosomiasis

It is characterized by Winterbottom’s Sign: swelling of the cervical lymph nodes in the head and neck area.

CNS symptoms include a shuffling gait (like a stroke victim), slurred speech, and malaise (needing to sleep longer and longer each day).

They are also restless at night.

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Winterbottom’s Sign47

Trypanosomiasis

CNS symptoms Shuffling gait Slurred speech Malaise (sleeping all day)

Treatment Melarsoprol: which has dangerous side-effects

like chemotherapy. This drug requires administration with a substance called ethylene glycol, which will break down regular plastic tubing, so the drug must be administered with special plastic iv tubing.

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Trypanosoma brucei

Trypomastigote stages are the only form found in patients.

Blood-saliva route Posterior kinetoplast Centrally located nucleus Undulating membrane Anterior flagellum

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Trypanosoma brucei50

Trypanosoma brucei

Trypomastigote

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Trypanosoma52

Tsetse Fly54

Trypanosoma cruzi

Disease: American Trypanosomiasis“Chaga’s Disease” A zoonotic disease (can infect animals) that

can be transmitted to humans by blood-sucking bugs.

This organism is a little smaller than T. bruceii and has a larger kinetoplast.

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“Chaga’s Disease”

This disease is NOT found in Africa. The vector is a large bug called the “Kissing Bug”. It is found in warm regions and crowded areas,

especially in the cracks of adobe huts. It comes out at night and crawls on a human while

they sleep.

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Kissing Bug58

Trypanosoma cruzi

Triatomine bug, Trypanosoma cruzi vector, defecating on the wound after taking a blood meal.

Fecal-blood route

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It is called the kissing bug because it prefers the lips because the blood supply is close to the surface and also it is attracted to the CO2 emissions.

It sucks the blood there, but they don’t transmit the organism this way.

When they suck the blood, they also defecate, and the organism is in the feces.

When the human wakes up to scratch the itch, feces get into the tiny wound.

This is a fecal- blood route.

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Romana’s sign

Swollen eye, seen in Chaga’s disease.

LA Times article on Chaga’s Disease

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http://www.latimes.com/health/la-me-chagas-20120708,0,4483738.story


Symptoms include fever, anorexia, swollen lymph nodes, hepatosplenomegaly (enlarged liver and spleen), and myocarditis (inflammation of the heart), which usually causes death.

They also have megacolon (large colon) and megaesophagus (large esophagus).

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Trypanosoma cruzi63

Trypanosoma brucei and cruzi

Trypanosoma bruceiSmaller posterior kinetoplast

Trypanosoma cruziLarger posterior kinetoplast

African Trypanosomiasis“Sleeping sickness”

American Trypanosomiasis“Chaga’s Disease”

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Trypanosoma cruzi65

Trypanosoma cruzi

large kinetoplast

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Leishmania donovani

Disease: LeishmaniasisVector-borne disease transmitted by

sandflies.

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Leishmania Life Cycle

Kinetoplast

It starts out as a spindle-shaped, single flagellated cell called a promastigote (mastigote means flagella).

You can also see the nucleus and a kinetoplast (mass of circular DNA).

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Leishmania rosette

In prepared slides you can see promastigotes align their nose in a circle, called a rosette.

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Leishmaniasis rosette71


It reproduces in the gut of a female sandfly, and migrates to her proboscis (mouth part).

It is introduced into the human by her bite. It then enters a macrophage and becomes

intracellular. Here, it loses its flagella and is now known

as an amastigote.

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Leishmaniasis

These amastigotes multiply in various organs including the spleen, liver, and lymph nodes.

Symptoms include hepatosplenomegaly, lymph adenopathy, fever, weight loss, and a decrease in all blood cells: WBC, RBC, and platelets.

The treatment is almost as bad as the disease because of the side effects. It is best to catch it early.

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The female sandflies inject the infective stage, promastigotes, during blood meals.

Macrophages phagocytize them and they transform into amastigotes.

Other sandflies become infected during blood meals when they ingest infected macrophages.

In the sandfly's midgut, the parasites differentiate into promastigotes, which multiply and migrate to the proboscis.

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Leishmaniasis Life Cycle

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Leishmania donovani (Promastigote)Single flagellum found in sand flies

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Leishmaniasis

Amastogotes

Amastogotes with nucleus and kinetoplast

Macrophage rupturing

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Leishmania

Amastigotes

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Sand Fly

This looks like a mosquito, except its body is hairy and the wings are feathery.

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Leishmaniasis

Geographic Distribution:More than 90 percent of the world's cases of visceral leishmaniasis are in India, Bangladesh, Nepal, Sudan, and Brazil.

Leishmaniasis is also found in Mexico, Central America, and South America, southern Europe, Asia, the Middle East, and Africa.

More and more cases are reported in the US, especially Texas and surrounding areas.

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Leishmaniasis

There are three forms of Leishmaniasis:

CutaneousMucocutaneusVisceral

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Cutaneous Leishmaniasis

The disease is only at the site of the bite. This form is seen in Texas, Mexico, Asia, and the

Middle East (our Iraq troops are coming down with this form).

It manifests as a large, wet sore with raised edges. It looks like a volcano with weepy serum coming out of the center.

The wound is not contagious, just the sandfly bite. Dogs can get this disease, too.

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Leishmaniasis (cutaneous)83

Leishmaniasis (mucocunateous)

This is when the disease located in the mucous membranes of the nose and mouth.

The most gruesome photos are of this form.

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Leishmaniasis (mucocunateous)87

Leishmaniasis (visceral)

This is the most serious form. It occurs especially in immunocompromised people, especially HIV patients. The amastagotes reproduce inside macrophages. Only T-cells can kill infected macrophages, but

HIV is a disease that infects T-cells. This form is known as Kala Azar.

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Kala Azar

Hepatosplenomegaly

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Kala Azar (duodenum)90







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Phylum: Ciliata (ciliates)

Paramecium spp (free living; non-parasitic) Oral groove (mouth)

Balantidium coli (intestinal parasite) Cytostome (mouth)

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Phylum: Ciliata(Ciliates)

Ciliates (move by cilia)

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Paramecium95

Balantidium coli

Disease: Balantidiosis The animal reservoir is the pig. Its

geographical distribution is world-wide, wherever humans and pigs live nearby each other.

This is the only ciliated protozoan that causes disease in humans.

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Balantidiosis

This is almost identical to Entamoeba histolytica. The cyst form is infective. It has a thick wall to protect it from stomach

acid. It enters the human (and dogs) by ingestion of

fecal contaminants on food, water, and hands.In the trophozoite form, they reproduce in the

large intestine, invade the colon wall, and cause ulcerations in the colon.

Like Entamoeba, it leaves a flask-shaped ulcer. Symptoms include diarrhea and GI discomfort.

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Balantidium coli

Trophozoites characterized by: Large size (40 µm to more than 70 µm). Presence of cilia on the cell surface A cytostome (where they take in food) A bean shaped macronucleus which is often

visible and a smaller, less conspicuous micronucleus.

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Balantidium coli

Trophozoites

Cytostome

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Balantidium coli

Trophozoites

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Balantidium coli Trophozoite101

Balantidium coli Cyst 102

Balantidium coli

Cysts

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Balantidium coli

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APICOMPLEXA

Characteristics: has an organelle called an apical complex which allows the organism to attach to the host.

They all require a biological vector for transmission (to get into the blood of the host).

Organisms Plasmodium

Disease: Malaria Toxoplasma gondii

Disease: toxoplasmosis Cryptosporidium parvum

Disease: Cryptosporidiosis

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Phylum: Apicomplexia(Non-motile obligate parasites)

Plasmodium spp (blood and liver parasite) Sporozoite stage: Sporozoites Hepatic stage: Merozoites Blood stage: Ring stage trophozoites

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Plasmodium spp

Disease: Malaria200-300 million infections a year2-3 million deaths a yearAffects mostly young people and teenagers2/3 of the cases are in Africa

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Malaria

The term “malaria” comes from “mal air”, which means “bad air”.

They used to think malaria was caused from the bad air of a foul-smelling swamp.

Later it was discovered that the disease was caused by the protozoa inside the mosquito.

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Malaria

Sporozoites migrate into the salivary gland of the mosquito, and they are injected into the blood of the human.

They immediately go to the liver. This is the only way to get malaria; you can’t get it

from a blood transfusion because the transmission form is the sporozoite. As soon as they get to the liver, they change into a merozoite and are no longer contagious.

They go right to the liver quickly to begin their next cycle.

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Terms

Sporozoite: formed by sexual reproductionTrophozoite: motile form of protozoaCyst: non-motile form of protozoaMerozoite: Special name of the trophozoite form of

Plasmodium after it hatches from a schizont.Schizont: sack of Plasmodium organisms formed by

sporozoites that have entered the liver. They metamorphasize into merozoites within the schizont (sack), multiply until they rupture the sack and spread.

Schizogony: the process of forming a schizont.Gametocyte: some merozoites differentiate into a male

or female gamete. These are taken up by the mosquito, and they combine into a zygote (sporozoite) in the mosquito.

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Plasmodium

The malaria parasite life cycle involves two hosts. Sporogenic Stage

During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host.

Hepatic Stage Sporozoites infect liver cells, form schizonts, metamorphasize into

merozoites and multiply until the schizont ruptures and releases the merozoites into the bloodstream.

Blood Stage Merozoites infect red blood cells The parasites undergo asexual multiplication in the erythrocytes. The ring stage trophozoites form another schizont, which ruptures,

releasing merozoites. Some parasites differentiate into male and female gametocytes. Blood stage parasites are responsible for the clinical manifestations of the

disease.

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Schizont: Hepatic Stage113

Schizont: Hepatic Stage114

Blood Phase: Rings115

Blood Phase: Rings116

Malaria

Merozoites being released from lysed RBC.

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Gametocyte: Blood Stage118

Gametocyte: Blood Stage119

Malaria

Symptoms Fever, chills, sweating, headaches, muscle pains Severe complications (cerebral malaria, anemia,

kidney failure) can result in death.

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Plasmodium - Malaria

endemic malaria has been eradicated from U.S. occurs in developing countries current problems with drug resistance by the

protozoan and insecticide resistance by vector

estimated that 40% of world’s population is at risk of acquiring malaria

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Malaria death rates(1900-1997)

Mandell, Figure 275-1 122

Malaria (the problem)

~3000 children die of malaria/day in Africa1946 the CDC was founded to combat

malaria millions of cases of malaria in the U.S. in 1930s in the U.S. the species of Anopheles that transmitted

the parasite preferred to feed on cattle rather than humans

disease eradicated in U.S. in the 1950s2009 report in Emerging Infectious Disease

that there are ~3,000 cases of non-endemic malaria in the U.S. each year

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Plasmodium – Life Cycle

Mosquito (Anopheles) takes blood meal and injects sporozoites sporozoites travel to liver cell (metamorphosis into trophozoite

form, called merozoites) They reproduce in the liver in a sack called a schizont (process is

called schizogony) and transform into merozoites. They multiply rapidly until the sack ruptures, releasing the merozoites.

merozoites leave liver and enter RBCs (ring stage) merozoites kill RBC and then:

infect more RBCs to make more merozoites OR gametocytes

gametocytes taken up by mosquito gametes join to form zygote, which develops into a sporozoite sporozoites move to salivary glands

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Plasmodium – Life Cycle

once mosquito infected, infected for life mosquito LC ~10 days (depending on

temperature) Anopheles bites many times

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Plasmodium

128

Human malaria

4 (major) species that infect humans P. vivax P. falciparum P. malariae P. ovale

Pathology bursting RBCs – release of “toxins” “sticky” RBCs can cause blockage in blood vessels

(especially in lungs, kidney, spleen and CNS) Sickle-cell patients resistant to falciparum malaria Glucose-6-phosphate dehydrogenase deficiency patients

have milder falciparum symptoms (parasite needs this enzyme)

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Malaria paroxysm

presents as acute febrile illness often followed by chills and rigors, then fever spikes (up to 40C/104F) and sweating severity depends on

species of Plasmodium age of patient (more severe in children under 5) other pathological conditions (superimposed bacterial

infections, malnutrition, etc)

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Malaria pathology

symptoms due to: host response

fever – waste products of RBCs overproduction of cytokines (e.g. TNF)

paroxysm – sudden appearance of symptoms that come and go. chills first, then fever, then back to normal until next attack

(symptoms last ~8-12 hours) falciparum has no stage where patient feels good

anemia destruction of RBCs; cannot recycle iron fast enough infected cells can stick to un-infected RBCs which are then lysed ↓ RBC production by bone marrow (TNF ↓ erythropoietin)

Cerebral malaria - P. falciparum - ~10% of cases thought to be due to infected RBCs sticking to endothelial cells (including

in the CNS) Relapse (Recrudescence) (P. vivax/P. ovale /P. malariae)

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Treatment

Quinine Synthetic drugs: chloroquine, primaquine, etc

multi-drug resistance (P. falciparum)vaccination

difficult because infection doesn’t provide effective life-long immunity

organisms shed protein coats different antigens during infectious cycle

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Anopheles Mosquitoes

Female mosquitoes need blood meals to nourish their eggs.

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Bacteria-infected mosquitoes may halt malaria

Scientists have infected mosquitoes with a bacteria known as Wolbachia, which sabotages malaria-causing parasites in the bugs, limiting their ability to spread malaria to humans.

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Toxoplasma gondii

Disease: Toxoplasmosis Infects most species of warm blooded animals, including

humans.Cats are the only known definitive hosts for the sexual

stages of T. gondii and thus are the main reservoirs of infection.

Cats become infected by eating infected wild animals (e.g. birds)

Tissue cysts or oocysts are excreted in the feces.Oocysts can survive in the environment for several

months and are remarkably resistant to disinfectants.Pregnant women who clean the litter box can catch

the mild disease, but the fetus has severe symptoms.

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Toxplasmosis

Most primary infections produce no symptoms. The time between exposure to the parasite and symptom development is 1 - 2 weeks. The disease can affect the brain, lung, heart, eyes, or liver.

Symptoms are mild illness with fever, muscle pain, sore throat, headache, enlarged lymph nodes.

This organism prefers nerve tissue, so it travels to the CNS.

Pregnant women should avoid cleaning cat litter boxes, because the fetus can develop mental retardation, blindness and epilepsy, and stillbirths.

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Toxplasmosis Cyst

Cyst in brain tissue

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Toxplasmosis Trophozoites

Trophozoites

142

Toxoplasmosis Trophozoites143

Toxoplasma Trophozoites sometimes form rosettes

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Toxplasmosis

Oocyst

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Toxplasmosis

Ocular toxoplasmosis

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Toxplasmosis

Cats causing suicide?http://fxn.ws/RwfYvQ

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Cats causing suicide?

Toxoplasma antibodies (proof of exposure to the parasite) are elevated in patients with schizophrenia.

There is also an increased rate of suicide attempts in those with the infection. A Dutch study looked at 45,000 pregnant women and found that 27% had antibodies to toxoplasma.

In those 27%, self-destructive violence was more common by about 50%. And the higher the antibodies to toxoplasm (presumably showing a more significant exposure), the greater the risk. Those with the highest level of antibodies were at almost 100 percent higher risk for self-harm.

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Cats causing suicide?

The actual completed suicide rate was over twice as high in women who had been exposed to toxoplasma compared to those who had not.

One reason toxoplasma could trigger severe psychiatric symptoms—including suicides—is that it causes inflammation in the central nervous system, raising the levels of inflammatory compounds like interleukin-6.

Those inflammatory compounds may be neurotoxic.

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Cryptosporidium parvum

Disease: Cryptosporidiosis Spread through the fecal-oral route, often

through contaminated waterCauses self-limiting diarrhea in people with

intact immune systems. In immunocompromised individuals (such as

AIDS patients), symptoms are severe and often fatal. AIDS patients have been known to have 50 stools a day, with tremendous water and weight loss. In these patients, the disease may persist for years.

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Cryptosporidium151







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subkingdom: protozoa (“first animal”) kingdom: protista 1

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