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
What is the treatment, prevention, and control of cryptosporidiosis?
- Symptomatic/ supportive therapy
- cysts very resistant to chlorine
What unicellular coccidian parasite is responsible for causing cyclosporiasis?
Cyclospora cayetanensis
What disease does the unicellular parasite, Cyclospora cayetanensis cause?
- Cyclosporiasis
How does one become infected with Cyclospora cayetanensis?
- Infection is transmitted through contaminated food or water
What are the clinical manifestations of cyclosporiasis?
- Diarrhea, loss of appetite, cramps, bloating, nausea, vomitting, fever, fatigue, and weight loss
How would you diagnose someone with cyclosporiasis?
- Observation of oocysts in feces
What is the treatment, prevention, and control of cyclosporiasis?
- Combination of drugs and fluids
- No vaccine is available
- Avoidance of contaminated food and water
What is the leading cause of waterborn infection?
Giardiasis
Somone with giardiasis would have parasites found where in their body?
- Their small intestine
What groups of people are a high risk group for giardiasis?
- Campers drinking unfiltered water are a high risk group
Giardiasis is caused by what?
-
Giardia intestinalis
- forms cysts and trophozoites
- trophozoites attach to intestinal epithelium and interferes with nutrient absorption
How is giardiasis transmitted?
- Transmission usually by cyst-contaminated water
- numerous animal reservoirs
- asymptomatic human carriers are common
- more serious disease in children
What are the clinical manifestations of giardiasis?
- Acute giardiasis
- severe diarrhea, epigastric pain, cramps, voluminous flatulence, and anorexia
- Chronic gastritis
- intermittent diarrhea with periodic appearance and remission of symptoms
How would you diagnose someone with giardiasis?
- Observation of cysts of trophozoites in stools, and ELISA
What is the treatment, prevention, and control for giardiasis?
- Antiprotozoal agents
- Avoiding contaminated water and use of slow sand filters in processing of drinking water
What method of movement does Giardia lamblia use?
Multiple flagella found on the end of the organism
What is the most common method of detection for Giardiasis?
- PCR, although classically the string test was used
How do people become infected with Giardiasis?
- Drinking fresh water that has become contaminated
Toxoplasmosis is a worldwide very common disease caused by what?
-
Toxoplasma gondii
- apicomplexan (non motile) protist
- most are asymptomatic
- reservoirs include wild rodents, birds, and small mammals
How is Toxoplasmosis transmitted?
- Fecal-oral transmission from infected animals
- also by ingestion of undercooked meat, congenital transfer, blood transfusion, or tissue transplant
What are the clinical manifestations of Toxoplasmosis?
- usually asymptomatic or resembles mononucleosis
- encephalitis can be fatal in immunocompromised hosts
- tachyzoites cross placenta and infect fetus, causing serious congenital defects or death
What is the diagnosis for toxoplasmosis?
- Serological tests
What is the treatment, prevention, and control of toxoplasmosis inclusive of?
- antiparasite therapy
- minimizing exposure by: avoidance of raw meat, washing hands after soil work, cat-handling practices
Summarize the Trichomonads
- do not require oxygen
- possess hydrogenosomes
- asexual reproduction only
- symbionts of digestive, reproductive, and respiratory tracts of many vertebrates, including humans
- some strains are human pathogens
What doesTrichomonas foetus cause?
- Spontaneous abortion in cattle
What does Dientamoeba fragalis cause?
- Diarrhea in humans
What does Trichomonas vaginalis cause?
- Trichomoniasis (sexually transmitted infection in humans)
- 7 million cases in U.S.
- 180 million worldwide
Trichomoniasis is a urogenital disease. How is it transmitted?
- It is transmitted through sexual contact
True or False: Only females can get trichomoniasis?
- False, both males and females can get trichomoniasis.
What percentage of people are infected with trichomoniasis and have no symtptoms?
70%
What are some symptoms associated with trichomoniasis?
- itching
- burning
- foul green-yellow discharge
True or False: A trichomoniasis infection must be cleared up before the delivery of a baby to prevent the baby from becoming infected?
- True
What flagellated protist is responsible for the STI trichomoniasis?
- Trichomonas vaginalis
What common sexually transmitted disease is Trichomonas vaginalis responsible for?
- Trichomoniasis
What are the clinical manifestations of trichomoniasis?
- Accumulation of leukocytes at site of infection
- In females, yellow purulent vaginal discharge/itching
- In males, usuall asymptomatic or burning urination
How would you diagnose someone with trichomoniasis?
- Observation of parasite in vaginal discharge, semen, or urine
The teatment, prevention, and control of trichomoniasis is inclusive of what?
- Antiparasite therapy
What method of movement does trichomoniasis use?
- Flagella
What sample from the human body would you find Trichomonas in?
- Swabs of the urogenital tract would contain the parasite
What is the most common way to become infected with Trichomoniasis?
- Sexual contact
What is blastomycosis?
- A systemic mycosis caused by Blastomyces dermatitidis (dimorphic fungus)
What organism causes blastomyces, a systemic mycosis (disease)?
Blastomyces dermatitidis
What are the three clinical forms of blastomycosis?
- Cutaneous
- Pulmonary
- Disseminated
What type of disease is blastomycosis?
- Airborne disease
How does Blastomyces dermatitidis cause cutaneous ulcers and abcesses?
- After lung inhalation spreads rapidly to skin causing cutaneous ulcers and abcesses
How would you diagnose blastomycosis?
- Serological tests
What types of treatment would you provide to treat blastomycosis?
- Amphotericin B/ other anti-fungal drugs for treatment
What systemic mycoses does Coccidioides immitis cause?
- Coccidioidomycosis
- endemic areas
- Valley fever, San Joaquin fever, or Desert Rheumatism
- dimorphic
- inhale the arthoconidia, converts to largespherule in body
- endemic areas
How would you diagnose coccidioidomycosis?
- Demonstration of spherule
What does the prevention of coccidioidomycosis involve?
- Prevention involves avoiding exposure to dust
What type of disease is Cryptococcosis?
- Airborne disease
What is cryptococcosis?
A systemic mycosis caused by yeast Cryptococcus neoformans
What yeast is responsible for the systemic mycosis cryptococcosis?
- Cryptococcus neoformans
What is the source of cryptococcosis?
- The source is dried pigeon droppings
Inhalation of Cryptococcus neoformans can lead to what complications?
- Serious disease including meningitis in immunocompromised (e.g., AIDS); mild or pneumonia-like in others
How would you diagnose someone with cryptococcosis?
- Detecting encapsulated yeast in clinical specimen
True or False: Histoplasmosis is an airborne disease?
True
True or False: Histoplasmosis is a common lung disease?
True
Histoplasmosis, a common lung disease, is caused by what pathogen?
Histoplasma capsulatum (dimorphic)
What systemic mycoses does Histoplasma capsulatum cause?
Histoplasmosis (a common lung disease)
How is histoplasmosis transmitted?
- Inhalation of airborne micronidia in bird droppings
- converts to yeast phase in body; flu-like illness
- only rarely becomes disseminated
How would you prevent/control for Histoplasmosis (common lung disease)
- Prevented/ controlled by wearing protective clothing in endemic areas and by soil contamination
What problem/complication does Tinea capitis cause?
- Infection of scalp hair
What problem/complication does Tinea pedis cause?
- Athlete’s foot
What problem/complication does Tinea unguium cause?
- Infection of the nailbed
What problem/complication does Tinea cruris cause?
- Jock itch
Aspergillus Fumigatus and A. flavus can cause what disease?
- Aspergillosis
Aspergillosis is usually caused by what pathogen?
- Usually caused by Aspergillus fumigatus
- Also caused by A. flavus
What is Apsergillosis?
- An invasive disease that results in pulmonary infection
- with fever, chest pain and cough that disseminates to brain and kidney
- in severely compromised individuals, lungs may fill with mycelia
How is the diagnosis of Aspergillosis made?
- By examination of pathological specimens or by isolation and characterization of fungus
How would you treat Apergillosis?
- Treament with antifungal drugs; treat underlying disease
What pathogen(s) is responsible for Cadidiasis?
-
Candida albicans or C. glabrata
- members of normal microbiota but numbers are kept in check by other microbes
- disease in healthy individuals occurs as result of disruption of normal microbiota
- can also be spread by sexual contact
- wide spectrum of diseases but most infections involve the skin or mucous membranes
- members of normal microbiota but numbers are kept in check by other microbes
True or False: Candidiasis can not be spread through sexual contact?
- False, Candidiasis can be spread through sexual contact
What types of diseases result from Candida albicans or C. glabrata infections?
- Wide spectrum of disease but most infections involve the skin and mucous membranes
True or False: Candida albicans or C. glabrata are kept in check by the presence other normal microbiota?
True
Under what conditions could someone healthy become infected with Candida albicans or C. glabrata?
- Disease in healthy indivduals occurs as result of disruption of normal microbiota
Summarize nosocomial Candidiasis
- important nosocomial pathogens
- May represent up to 10% of nosocomial bloodstream infections
- mortality ~50% when in bloodstream and disseminates to visceral organs
Oropharyngeal candidiasis (thrush)?
- Commmon disease of newborns, denture wearers, and those on steroid therapies
Paronychia and onychomycosis?
- Associated with Candida infections of the subcutaneous tissues of digits and, nails, respectively
- usually result from continued immersion of hands
Intertriginous candidiasis?
- Involves axillae, groin, and skin folds
Napkin (diaper) candidiasis?
- Found in infants whose diapers are not changed frequently
Candidal vaginitis?
- Occurs when lactobacilli are depleted
Balanitis (a type of candidiasis)?
- Transmission to males during intercourse
- infection of glans penis; occurs primarily in uncircumcised men
What is the diagnosis for candidiasis?
- Diagnosis of candidiasis is difficult
What is the treatment, prevention and control of candidiasis inclusive of?
- No satisfactory treatment
- anti-fungals used for cutaneous lesions and systemic candidiasis
Microsporidiosis results from the infection of what pathogen?
- Microsporidia
- Obligate intracellular fungi that belong to phylum Microspora
- an emerging infectious disease, found mostly in HIV patients
Micrsopora are responsible for what emerging infectious disease, found mostly in HIV patients?
- Microsporidiosis
What are some reservoirs for microsporidia?
- Domestic and feral animals are reservoirs for species that infect humans
True or False: Microsporidia produce highly resistant spores?
- True
How does one become infected with microsporidia?
Infection of host cells occurs when microsporidia extrudes polar tubule from within the spore
What are the symptoms of a microsporidia infection (Microsporidiosis)?
- Wide variety including hepatitis, pnuemonia, skin lesions, diarrhea, weight loss, and wasting syndrome
What is the diagnosis for a microsporidia infection (microsporidiosis)?
- Based on clinical symptoms and identification of microsoridia in gram- or geima-stained specimens
- Identification can also be made using electron microscopy or PCR
What is the treatment, prevention, and control of microsporidia infection (microsporidiosis) inclusive of?
- Some treatment success with antifungal drugs
This fungus is found in the lungs of a variety of mammals?
- Pneumocystis jiroveci (previously carinii) causes Pnuemocystis pneumonia which is indicated as PCP
Pneumocystis pneumonia is casued by what pathogen?
Pneumocystis jiroveci (previously carinii)
Pneumocystis pneumonia (PCP) occurs almost exclusively in what types of hosts?
- PCP occurs almost exclusively in immunocompromised hosts
- organism and disease remain localized in the lungs (high mortality rate)
- e.g., patients on immunosuppressive drugs
- e.g., AIDS patients
What is the laboratory diagnosis for Pneumocystis pneumonia (PCP)?
- Microscopic observation of organisms in lung tissue or PCR
What is the treatment, prevention, and control of Pneumocstis pneumonia (PCP) inclusive of?
- Oxygen therapy or a combination of drugs
- prevention and control is through prophylaxis with drugs in susceptible people