Exam III- organisms Flashcards
Flagellated protist belonging to the Trypanosoma spp. are responsible for what diseases?
- Sleeping sickness (T. gambiense and T. rhodesiense)
- Chagas’ disease (Trypanosoma cruzi)
Members of the genus Leishmania cause leishmaniasis. What symptoms are associated with this disease?
systemic and skin/membrane damage
What organism causes Chagas’ disease?
Trypanosoma cruzi
How is Chagas’ disease transmitted?
Kissing bugs
Chagas’ disease causes damage to what?
damage to the nervous system
What two organsims can cause African sleeping sickness?
- T. gambiense
- T. rhodesiense
What is trypanosomiasis caused by?
- Caused by trypanosomes
- group of flagellate protists
- change its protein coat and evades the immunologic response
How is trypanosomiasis transmitted?
- By tsetse flies (African trypanosmiasis) or kissing bugs (Chagas’ disease)
- reservoirs include domestic catle and other animals
Reservoirs for the trReservoirs for trypanosomiasis are inclusive of what?
- reservoirs include domestic cattle and other animals
How would you diagnose someone with trypanosomiasis?
- Diagnosis is made by the observation of motile parasites in blood or antibody levels
What are the clinical manifestations of African Trypanosomiasis?
- interstitial inflammation and necrosis within lymph nodes and small blood vessels of brain and heart, leading to lethargy (hence name, sleeping sickness) and death within 2 to 3 years
True or False: Drug therapy is available for the treatment of African trypanosomiasis?
True
Why are vaccines not useful for the treatment of African trypanosomiasis?
- Vaccines are not useful due to antigenic variation
Trypanosomes have a thick glycoprotein layer coating their cell wall which is changeable. How is this beneficial to the parasite?
- it allows for the parasites to escape from the host immune system
Summarize antigenic variation.
- thick glycoprotein layer coating cell wall surface which is changeable
- enables the parasite’s escape from the host immune system
- no vaccines
- new drugs may target flagellar axonemal proteins important for division
How does the triatome bug transmit Chagas’ disease
- triatome bug takes blood meal, defecates in wound
- trypanosome in feces is scratched into the body
Summarize the accute form of Chagas’ disease
- rapid onset, trypanosome moves through the bloodstream, enters cells, becomes amastigote, and replicates
- may be cleared or develop chronic form
- treatment may be effective at this stage
True or False: The accute form of Chagas’ disease may be cleared or develop into the chronic form?
True
Is treatment effective for the accute form of Chagas’ disease?
- Yes, treatment may be effective at this stage
Summarize the Chronic form of Chagas’ disease.
- amastigotes reach heart, gastrointestinal and other cells
- replicate causing heart disease and other disorders due to destruction of parasitized cells in the liver, spleen, lymph nodes, GI, and central nervous system
What is the only type of treatment available for the chronic stage of Chagas’ disease?
- Investigational treatment
Why are vaccines not effective for the treatment of Chagas’ disease?
- Vaccines are not effective due to antigenic variation of trypanosome
What is Leishmaniasis caused by?
- Caused by Leishmania flagellated protist
- Leishmania donovani, L. tropica, L. mexicana
These flagellated protists cause Leishmaniasis?
- Leishmania donovani, L. tropica, L. mexicana
How is leishmaniasis transmitted?
- Transmitted by sandflies when they take a blood meal
- animal reservoirs include canines and rodents, also blood transfusions and needles
Name some reservoirs for leishmaniasis.
- Animal reservoirs include canines and rodents, also blood transfusions and needles
What are the three forms of leishmaniasis infection?
- mucocutaneous
- cutaneous
- visceral
What is characteristic of cutaneous leishmaniasis?
- Lesions of mouth, nose, throat, and skin that cause extensive scarring and disfigurement
- papules that develop into crustated ulcers
- healing occurs with scarring, permanant immunity
How would you diagnose someone with leishmaniasis?
- Observation of parasites within infected macrophages, cultural and serological tests
What would the treatment, prevention, and control of leishmaniasis include?
- antiparasite therapy
- vector and reservoir control, and epidemiological surveillance
How do amebae such as Enatamoeba and Acanthamoeba move around?
- they move by pseudopods
This amoebid parasite is most common in tropical regions of the world?
- Entamaeoba histolytica
True or False: Entamoebida lack mitochondria, but have hydrogenosomes?
- True
- may possess 20 mitochondrial proteins
What disease does Entamoeba histolytica cause?
Amebiasis (Amoebic dysentery)
What disease is caused by consuming E. histlytica cysts?
- Amebiasis (amoebic dysentery)
How does one become infected with E. histolytica ?
- Infection occurs by ingestion of mature cysts from fecally contaminated water, food or hands, or from fecal exposure during sexual contact
What are the clinical manifestations of Amebiasis (Amoebic dysentery)?
- asymptomatic to fulminating dysentery, exhaustive diarrhea, appendicitis, and abcesses of liver, lungs, and brain
True or False: E. histolytica cysts may migrate to lungs, brain, liver, or skin?
- True
What is the third leading cause of parasitic death worldwide?
-
E. histolytica infection
- Causes amoebic dysentery
How would you diagnose someone with amebiasis?
- observation of trophozoites in fresh warm stools or cysts in ordinary stools, and serological tests
What does the treatment, prevention, and control of amebiasis include?
- antiprotozoal agents
- avoiding contaminated water and food and hyperchlorination or iodination of water supplies to destroy waterborne cysts
What organ gets damaged by Entamoeba histolytica ?
- Small intestines
How does Entamoeba histolytica move around?
- Pseudopods, or false feet typical of amoeba
What mode of transmission does Entamoeba histolytica use?
- Fecal/oral, typically vehicle involved
What falcultative (opportunistic) parasites cause amebic meningoencphalitis and keratitis?
- Caused by the free-living amoebae Naegleria and Acanthameba
The free-iving amoebae Naegleria and Acanthamoeba are responsible for what diseases?
- Amebic meningoencephalitis
- keratitis
What are the clinical manifestations of amebic meningoencephalitis and keratits?
- Primary amebic meningoencephalitis
- Granulomatous amoebic encephalits
- Keratitis- progressive ulceration of the cornea
What is keratits?
- Progressive ulceration of the cornea
- one of the clinical manifestations for amebic meningoencephalitis and keratitis
What is the diagnosis for amebic meningoencephalitis and keratitis?
- Demonstration of amoeba in clinical specimens
What does the treatment, prevention, and control of amebic meningoencephalitis and keratitis include?
- no drug therapy available
- do not use water for contact lens care
The use of water for contact lens care should be avoided because of the posibility of becoming infected with free living amoebae. Which amoebae are responsible for this and what diseases do they cause?
- Naegleria and Acanthamoeba
- Amebic meningoencephalitis and Keratitis
Four species of Plasmoium are the causative agents of what disease?
- Malaria
How is malaria transmitted?
- Transmitted by the bite of an infected female Anopheles mosquito
Describe the life cycle of plasmodial protists.
- Sporozoite injected with moquito bite
- Replicates as merozoite in hepatic cells
- Release, enters erythrocytes and replicates
- Lyses erythrocytes–correlates with fever
What are the clinical manifestations of malaria?
- Periodic attacks of chills and fever
- Anemia can result and the spleen and liver often hypertrophy
- Can cause cerebral malaria in children and non-immune individuals
What is the diagnosis for malaria?
- Demonstration of parasites within Wright- or Giemsa-stained red blood cells and serological tests
Treatment, prevention, and control of malaria is inclusive of what?
- Antimalarial drugs
- resistance has been observed
- chemoprophylaxis for travelers to endemic areas
- Prevention via netting/insecticide to control mosquitos
- New vaccine shows promise
What disease does Plasmodium protozoa cause?
Malaria
What body sample do physicians collect to diagnose malaria?
- Blood samples
What is the method of transmission for malaria?
- Bite from an infected female Anopheles mosquito
What is cryptosporidiosis?
- Emerging disease casued by Crytosporidium parvum
- apiclomplexan that forms cysts, sporozoites, and merozoites
- sporozoites parasitize intestinal epithelial cells
- apiclomplexan that forms cysts, sporozoites, and merozoites
How is cyrptosporidiodis transmitted?
- Transmitted from animal reservoirs in contaminated food or water
- many birds and mammals shed oocysts in feces
What disease does Cryptosporidium parvum cause?
- Cryptosporidiosis
What are the clinical manifestations of cryptosporidiosis?
- Diarrhea, abdominal pain, nausea, fever, and fatigue
- Usually self-limiting
- Can be fatal in late stage AIDS patients and other immunocompromised individuals