Unicellular Parasites - Amoebas and Apicomplexans

What is blending? Why is it a problematic practice?

*Blending*: mixing treated and untreated water within a sewage treatment plant prior to discharge Occurs frequently during heavy rainfall when water capacity is exceeded. Mixed waters are treated with *diluted chlorine* but at such low concentrations that parasitic cysts or oocysts are unaffected.

Trypanosoma brucei *Disease caused:* *Transmission:* *Symptoms:* - generalized symptoms ( fever, fatigue, headaches, swollen lymph nodes) - chancre can develop at site of infection - confusion, personality changes, and other neurologic problems when parasite invades CNS - *death* within months (East African Sleeping Sickness) or years (West African Sleeping Sickness).

*Disease caused:* African Trypanosomiasis ("Sleeping Sickness") *Transmission:* bite of an infected Tsetse fly *Symptoms:* - generalized symptoms ( fever, fatigue, headaches, swollen lymph nodes) - chancre can develop at site of infection - confusion, personality changes, and other neurologic problems when parasite invades CNS - *death* within months (East African Sleeping Sickness) or years (West African Sleeping Sickness)

Trypanosoma cruzi *Disease caused:* _________ *Transmission:* _________ *Symptoms*: typically asymptomatic Acute: fever, swelling at site of infection Chronic: - enlarged ________ , _________ , or ___________ - heart failure - death

*Disease caused:* Chagas Disease ("American Trypanosomiasis") *Transmission:* contact with feces of Triatomine ("Kissing") bug - contact with infected blood - congenital *Symptoms*: typically, asymptomatic Acute: fever or swelling at infection site Chronic: - enlarged *heart, esophagus, or colon* - heart failure - death

P. malariae

*Quartan* malaria

P. falciparum

*Tertian* Causes most *severe cases of malaria* - multiplies rapidly & causes severe blood loss i.e. anemia - cerebral malaria: fatal infection; parasite clogs small blood vessels in brain

Toxoplasma gondii (*Toxoplasmosis*) *Transmission:* ________ *Disease:* many people don't know they're infected; may experience *flu-like symptoms*. Severe forms of disease can result in damage to _______ , _________ (i.e. ocular toxoplasmosis), or other organs Severe Toxoplasmosis in: 1) ________ 2) ________

*Transmission*: eating undercooked meat containing oocytes from cat feces *Disease:* many people don't know they're infected; may experience *flu-like symptoms*. Severe forms of disease can result in damage to *brain, eyes* (i.e. ocular toxoplasmosis), or other organs Severe Toxoplasmosis in: 1) *pregnant women* - miscarriage, stillborn child, abnormalities at birth 2) *immunocompromised*

Giardia spp. (Giardiasis) *Transmission*: ____________ *Disease*: most frequently diagnosed intestinal parasite causing _________ disease and other gastrointestinal issues. Infected people may suffer from severe dehydration and weight loss

*Transmission*: ingesting parasite from food, water, other contaminated surfaces (including hands) *AND* person-to-person contact *Disease*: most frequently diagnosed intestinal parasite causing *diarrheal disease* and other gastrointestinal issues. Infected people may suffer from severe dehydration and weightloss

*Babesia microti* *Transmission:* ________ *Symptoms:* _________

*Transmission:* bite of an infectious blacklegged (deer) tick *Symptoms*: very similar to malaria (i.e. often misdiagnosed) - general symptoms (fever, chills, fatigue, headache, etc.) - *destroys RBC's leading to anemia* - *death*

*Balamuthia mandrilaris* *Transmission:* ___________ *Disease caused:* __________

*Transmission:* contact with contaminated soil *OR* inhaling dust containing the amoeba *Disease caused:* GAE (Granulomatus Amebic Encephalitis) - fatal infection of CNS

Cryptosporidium spp. (Cryptosporidiosis) *Transmission*: ___________ *Disease:* among many other gastrointestinal issues the major symptom is __________. Infected people may suffer from severe dehydration and weight loss.

*Transmission:* ingesting parasite in food, water, other contaminated surfaces (including hands) AND person-to-person contact *Disease:* among many other gastrointestinal issues the major symptom is *watery diarrhea*. Infected people may suffer from severe dehydration and weight loss.

*Acanthomoeba spp.* *Transmission:* most common route is through _________; may also enter body through nose or cuts in skin when in contact with contaminated water *Diseases caused:* 1. ____________ : inflammation of the cornea 2. ___________ : occurs when acanthomoeba migrates to CNS; can be fatal

*Transmission:* most common route is through *contact lens use*; may also enter body through nose or cuts in skin when in contact with contaminated water *Diseases caused:* 1. *Acanthamoeba Keratitis:* inflammation of cornea 2. *GAE (Granulomatous Amebic Encephalitis)*: occurs when acanthomoeba migrate to CNS; can be fatal

Acanthomoeba can cause Keratitis - inflammation of the cornea. Which individuals are most at risk of developing Keratitis?

*contact lens wearers* - make up ~85% of Acanthamoeba Keratitis cases - Acanthamoeba trophozoites can adhere to plastic surfaces (inlcuding contact lenses) and easily infect eye

What organisms do Coccidia spp. infect?

*domestic fowl* can destroy a farm in a short span of time if not treated

How do cysts of Giardia and Crytosporidium avoid being removed out of the water supply for North Battleford?

1) cysts *unaffected by concentration of chemicals* used to treat water 2) treatment plants rely on *floc to filter* any remaining parasites and bacteria 3) floc substance that would typically entangle cysts was removed during servicing, allowing cysts to easily leave treatment plant

What is the connection between deer, ticks, and Babesia microti?

1. B. microti is transmitted to humans through the bite of an infected tick 2. Deer are an important food source for the ticks, but are not infected by the parasite they harbor 3. Increases in deer populations increases tick populations and prevalence of B. microti infection

5 parasites that are members of Apicomplexans?

1. Toxoplasma gondii (Toxoplasmosis) 2. Plasmodium spp. (Malaria) 3. Crytosporidum spp. (Diarrheal Disease) 4. Babesia microti (misdiagnosed as Malaria) 5. Coccidia spp. (infects domestic fowl)

*Apicomplexans* are a mostly parasitic group. The defining characteristics of apicomplexans are: 1. ___________ -- flattened vesicle like structures found just beneath the palsma membrane 2. ___________ -- used to attach to and invade host cells; this complex consists of: --> secretory organelles called *micronemes* & *rhoptries* --> *polar rings* composed of microtubules --> a conoid

1. cortical alveolae 2. apical complex *NOTE:* most species also have an *apicoplast* which is a non-photosynthetic chloroplast involved in fatty acid, heme, and isoprenoid synthesis

What genetic factors provide protection against malaria?

1. sickle cell anemia or other hemoglobin-related disorders = resistance to P. falciparum 2. persons who are negative for the *Duffy blood group* are resistant to P. vivax. b. What age groups are most vulnerable to developing malaria? Young children and pregnant women. c. Give two factors that impede the eradication of malaria in areas where it is epidemic. (1) Poor, rural populations typically cann't afford the housing and bed nets that would protect them from mosquitoes. (2) Governments of malaria-endemic countries often lack financial resources, equipment, drugs, training, and supervision needed to properly recognize and treat malaria

*Amoeba Parasites* 1. *Acanthomeoba spp.* 2. Balamuthia spp.

Acanthomoeba spp. cause the most problems for humans; infections can be fatal

Fungi are considered more closely related to animals than to plants. How do you know this from looking at the relationship tree on a tree of life?

Animals and fungi share a more recent common ancestor than fungi and plants do.

What other species of free-living amoeba causes GAE?

Balamuthia spp.

What disease does your textbook feel Darwin battled with most of his life?

Chagas Disease; infected with T. cruzi

What problems can humans infected with Babesia microti exhibit?

Humans that contract Babesia microti are often misdiagnosed as having malaria due to the parasites symptoms being very similar. - general symptoms (fever, chills, fatigue, headache, etc.) - *destroys RBC's leading to anemia* - *death*

In a ________ malaria parasite, _________ are released ever 42-47 hours (two-day cycle). Quartan malaria parasite releases _________ every 72 hours (three-day cycle)

In a *tertian* malaria parasite, *merozoites* are released ever 42-47 hours (two-day cycle). Quartan malaria parasite releases *merozoites* every 72 hours (three-day cycle)

__________ causes acute meningoencephalitis leading to death in healthy children and young adults. It is known as the *brain eating amoeba*.

Naegleria fowleri

All malarian parasites have a tertian cycle *except* for _______.

P. malariae; only quartan parasite

P. ________ and P. ________ are two malarian parasites that have dormant liver stages (hypnozoites) that can activate and invade blood ("relapse") several months/years after initial infection.

P. vivax and P. ovale

P. vivax

Quotidian and Tertian Most *prevalent* (widespread) human malarian parasite Dormant liver stage (hypnozoites)

P. ovale

Tertian Biologically & morphologically similar to P. vivax; however, it can infect individuals who are *negative for Duffy blood group* Dormant liver stage (hypnozoites)

The life cycle of plasmodium spp. is split between _________ and _________. In the mosquitos gut, the parasite undergos sexual reproduction, multiplying rapidly to produce _________ which will be transmitted to humans. Once in the human host, _________ enter the liver. There they mature into _________, which rupture and release *merozoites*. (*REMEMBER*: P. vivax and P. ovale have dormant liver stages, i.e. hypnozoites) *Merozoites* proceed to invade red blood cells and undergo asexual reproduction, first becoming immature _________. This is the activated feeding stage of the parasite. The *trophozoite* matures into a *schizont*, a mother cell which ruptures and releases __________ which proceed to infect new RBC's. The rupturing of merozoites and subsequent infection of new RBC's is responsible for the clinical manifestations of the disease. Some immature *trophozoites* may mature into __________ which will fuse into a zygote once transmitted into the mosquito.

The life cycle of plasmodium spp. is split between *female mosquitos* and *humans*. In the mosquitos gut, the parasite undergos sexual reproduction, multiplying rapidly to produce *sporozoites* which will be transmitted to humans. Once in the human host, *sporozoites* enter the liver. There they mature into *schizonts*, which rupture and release *merozoites*. (*REMEMBER*: P. vivax and P. ovale have dormant liver stages, i.e. hypnozoites) *Merozoites* proceed to invade red blood cells and undergo asexual reproduction, first becoming immature *trophozoites*. This is the activated feeding stage of the parasite. The *trophozoite* matures into a *schizont*, a mother cell which ruptures and releases *merozoites* which proceed to infect new RBC's. The rupturing of merozoites and subsequent infection of new RBC's is responsible for the clinical manifestations of the disease. Some immature *trophozoites* may mature into *gametocytes* which will fuse into a zygote once transmitted into the mosquito.

12. How was the source of Toxoplasmosis around the city of Victoria confirmed? 3 pts.

The source of Toxoplasmosis was determined to be water from the Humpback Reservoir. No standard methods exist for testing water supplies for toxoplasmosis parasites; however, investigators found that the reservoir was often used by domestic and feral cats as well as wild cougars, many of which were determined to have been infected with T. gondii. It was noted that high water turbidity occurred during heavy rainfall, which increased runoff and washed debris from land into the water, including cat feces. The water therefore should have contained more T. gondii oocysts at these times and infected more people which was confirmed by the cluster of T. gondii infections occurring shortly after periods of heavy rainfall.

*_________* are produced in some of the infected red blood cells of the human hosts, but don't fuse into a zygote (oocyst) until transmitted into a mosquito

gametocytes

Why is T. cruzi considered an emerging parasite?

immigrants brought the parasite with them and with the advent of blood transfusions, began contaminating the blood supplies with Toxoplasma parasite; still, the parasite continues to be spread northward as immigrants from Latin America enter the United States

Acanthomoeba are also known to cause Granulomatous Amebic Encephalitis (GAE) when they migrate to the CNS; infection can be fatal. Which individuals are most at risk of developing GAE?

immunocompromised individuals

How is Naegleria fowleri transmitted?

infected water enters through the nose (especially when swimming/ diving in warm *freshwater places*) You *CANNOT* be infected by drinking water contaminated with Naegleria

*Trophozoite* is the general name for the activated feeding stage in the life cycle of protozoan parasites. The trophozoite develops into a *schizont*, a mother cell which asexually produces daughter cells which in the Plasmodium life cycle are also known as *________*.

merozoites

*________ * are the result of asexual reproduction (schizogony, merogony). In malaria, these cells *infect red blood cells and then rapidly reproduce asexually*. These new daughter cells then can break and destroy the red blood cell hosts and infect others.

merozoites

P. vivax is a tertian malaria parasite. It is also considered a ________ parasite because it may release merozoites every day.

quotidian

Why is B. microtis considered an imerging parasite?

scientists are now able to recognize the parasite in blood.

*_________* are cells that *infect new human hosts*. In the parasites that cause malaria (Plasmodium), for instance these cells *develop in the mosquito's salivary glands*, leave the mosquito during a blood meal, and enter the liver where they multiply. Liver cells infected with parasitic cells eventually burst, releasing merozoites into the bloodstream.

sporozoites