Exam III- organisms Flashcards
1
Q
Flagellated protist belonging to the Trypanosoma spp. are responsible for what diseases?
A
- Sleeping sickness (T. gambiense and T. rhodesiense)
- Chagas’ disease (Trypanosoma cruzi)
2
Q
Members of the genus Leishmania cause leishmaniasis. What symptoms are associated with this disease?
A
systemic and skin/membrane damage
3
Q
What organism causes Chagas’ disease?
A
Trypanosoma cruzi
4
Q
How is Chagas’ disease transmitted?
A
Kissing bugs
5
Q
Chagas’ disease causes damage to what?
A
damage to the nervous system
6
Q
What two organsims can cause African sleeping sickness?
A
- T. gambiense
- T. rhodesiense
7
Q
What is trypanosomiasis caused by?
A
- Caused by trypanosomes
- group of flagellate protists
- change its protein coat and evades the immunologic response
8
Q
How is trypanosomiasis transmitted?
A
- By tsetse flies (African trypanosmiasis) or kissing bugs (Chagas’ disease)
- reservoirs include domestic catle and other animals
9
Q
Reservoirs for the trReservoirs for trypanosomiasis are inclusive of what?
A
- reservoirs include domestic cattle and other animals
10
Q
How would you diagnose someone with trypanosomiasis?
A
- Diagnosis is made by the observation of motile parasites in blood or antibody levels
11
Q
What are the clinical manifestations of African Trypanosomiasis?
A
- 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
12
Q
True or False: Drug therapy is available for the treatment of African trypanosomiasis?
A
True
13
Q
Why are vaccines not useful for the treatment of African trypanosomiasis?
A
- Vaccines are not useful due to antigenic variation
14
Q
Trypanosomes have a thick glycoprotein layer coating their cell wall which is changeable. How is this beneficial to the parasite?
A
- it allows for the parasites to escape from the host immune system
15
Q
Summarize antigenic variation.
A
- 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
16
Q
How does the triatome bug transmit Chagas’ disease
A
- triatome bug takes blood meal, defecates in wound
- trypanosome in feces is scratched into the body
17
Q
Summarize the accute form of Chagas’ disease
A
- 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
18
Q
True or False: The accute form of Chagas’ disease may be cleared or develop into the chronic form?
A
True
19
Q
Is treatment effective for the accute form of Chagas’ disease?
A
- Yes, treatment may be effective at this stage
20
Q
Summarize the Chronic form of Chagas’ disease.
A
- 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
21
Q
What is the only type of treatment available for the chronic stage of Chagas’ disease?
A
- Investigational treatment
22
Q
Why are vaccines not effective for the treatment of Chagas’ disease?
A
- Vaccines are not effective due to antigenic variation of trypanosome
23
Q
What is Leishmaniasis caused by?
A
- Caused by Leishmania flagellated protist
- Leishmania donovani, L. tropica, L. mexicana
24
Q
These flagellated protists cause Leishmaniasis?
A
- Leishmania donovani, L. tropica, L. mexicana
25
How is leishmaniasis transmitted?
* Transmitted by sandflies when they take a blood meal
* animal reservoirs include canines and rodents, also blood transfusions and needles
26
Name some reservoirs for leishmaniasis.
* Animal reservoirs include canines and rodents, also blood transfusions and needles
27
What are the three forms of leishmaniasis infection?
1. mucocutaneous
2. cutaneous
3. visceral
28
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
29
How would you diagnose someone with leishmaniasis?
* Observation of parasites within infected macrophages, cultural and serological tests
30
What would the treatment, prevention, and control of leishmaniasis include?
* antiparasite therapy
* vector and reservoir control, and epidemiological surveillance
31
How do amebae such as *Enatamoeba* and *Acanthamoeba* move around?
* they move by pseudopods
32
This amoebid parasite is most common in tropical regions of the world?
* *Entamaeoba histolytica*
33
True or False: *Entamoebida* lack mitochondria, but have hydrogenosomes?
* True
* may possess 20 mitochondrial proteins
34
What disease does *Entamoeba histolytica* cause?
Amebiasis (Amoebic dysentery)
35
What disease is caused by consuming *E. histlytica* cysts?
* Amebiasis (amoebic dysentery)
36
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
37
What are the clinical manifestations of Amebiasis (Amoebic dysentery)?
* asymptomatic to fulminating dysentery, exhaustive diarrhea, appendicitis, and abcesses of liver, lungs, and brain
38
True or False: *E. histolytica* cysts may migrate to lungs, brain, liver, or skin?
* True
39
What is the third leading cause of parasitic death worldwide?
* *E. histolytica* infection
* Causes amoebic dysentery
40
How would you diagnose someone with amebiasis?
* observation of trophozoites in fresh warm stools or cysts in ordinary stools, and serological tests
41
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
42
What organ gets damaged by *Entamoeba histolytica* ?
* Small intestines
43
How does *Entamoeba histolytica* move around?
* Pseudopods, or false feet typical of amoeba
44
What mode of transmission does *Entamoeba histolytica* use?
* Fecal/oral, typically vehicle involved
45
What falcultative (opportunistic) parasites cause amebic meningoencphalitis and keratitis?
* Caused by the free-living amoebae *Naegleria* and *Acanthameba*
46
The free-iving amoebae *Naegleria* and *Acanthamoeba* are responsible for what diseases?
* Amebic meningoencephalitis
* keratitis
47
What are the clinical manifestations of amebic meningoencephalitis and keratits?
* Primary amebic meningoencephalitis
* Granulomatous amoebic encephalits
* Keratitis- progressive ulceration of the cornea
48
What is keratits?
* Progressive ulceration of the cornea
* one of the clinical manifestations for amebic meningoencephalitis and keratitis
49
What is the diagnosis for amebic meningoencephalitis and keratitis?
* Demonstration of amoeba in clinical specimens
50
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
51
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
52
Four species of *Plasmoium* are the causative agents of what disease?
* Malaria
53
How is malaria transmitted?
* Transmitted by the bite of an infected female Anopheles mosquito
54
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
55
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
56
What is the diagnosis for malaria?
* Demonstration of parasites within Wright- or Giemsa-stained red blood cells and serological tests
57
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
58
What disease does Plasmodium protozoa cause?
Malaria
59
What body sample do physicians collect to diagnose malaria?
* Blood samples
60
What is the method of transmission for malaria?
* Bite from an infected female Anopheles mosquito
61
What is cryptosporidiosis?
* Emerging disease casued by *Crytosporidium parvum*
* apiclomplexan that forms cysts, sporozoites, and merozoites
* sporozoites parasitize intestinal epithelial cells
62
How is cyrptosporidiodis transmitted?
* Transmitted from animal reservoirs in contaminated food or water
* many birds and mammals shed oocysts in feces
63
What disease does *Cryptosporidium parvum* cause?
* Cryptosporidiosis
64
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
65
What is the treatment, prevention, and control of cryptosporidiosis?
* Symptomatic/ supportive therapy
* cysts very resistant to chlorine
66
What unicellular coccidian parasite is responsible for causing cyclosporiasis?
*Cyclospora cayetanensis*
67
What disease does the unicellular parasite, *Cyclospora cayetanensis* cause?
* Cyclosporiasis
68
How does one become infected with *Cyclospora cayetanensis?*
* Infection is transmitted through contaminated food or water
69
What are the clinical manifestations of cyclosporiasis?
* Diarrhea, loss of appetite, cramps, bloating, nausea, vomitting, fever, fatigue, and weight loss
70
How would you diagnose someone with cyclosporiasis?
* Observation of oocysts in feces
71
What is the treatment, prevention, and control of cyclosporiasis?
* Combination of drugs and fluids
* No vaccine is available
* Avoidance of contaminated food and water
72
What is the leading cause of waterborn infection?
Giardiasis
73
Somone with giardiasis would have parasites found where in their body?
* Their small intestine
74
What groups of people are a high risk group for giardiasis?
* Campers drinking unfiltered water are a high risk group
75
Giardiasis is caused by what?
* *Giardia intestinalis*
* forms cysts and trophozoites
* trophozoites attach to intestinal epithelium and interferes with nutrient absorption
76
How is giardiasis transmitted?
* Transmission usually by cyst-contaminated water
* numerous animal reservoirs
* asymptomatic human carriers are common
* more serious disease in children
77
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
78
How would you diagnose someone with giardiasis?
* Observation of cysts of trophozoites in stools, and ELISA
79
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
80
What method of movement does *Giardia lamblia* use?
Multiple flagella found on the end of the organism
81
What is the most common method of detection for Giardiasis?
* PCR, although classically the string test was used
82
How do people become infected with Giardiasis?
* Drinking fresh water that has become contaminated
83
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
84
How is Toxoplasmosis transmitted?
* Fecal-oral transmission from infected animals
* also by ingestion of undercooked meat, congenital transfer, blood transfusion, or tissue transplant
85
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
86
What is the diagnosis for toxoplasmosis?
* Serological tests
87
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
88
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
89
What does*Trichomonas foetus* cause?
* Spontaneous abortion in cattle
90
What does *Dientamoeba fragalis* cause?
* Diarrhea in humans
91
What does *Trichomonas vaginalis* cause?
* Trichomoniasis (sexually transmitted infection in humans)
* 7 million cases in U.S.
* 180 million worldwide
92
Trichomoniasis is a urogenital disease. How is it transmitted?
* It is transmitted through sexual contact
93
True or False: Only females can get trichomoniasis?
* False, both males and females can get trichomoniasis.
94
What percentage of people are infected with trichomoniasis and have no symtptoms?
70%
95
What are some symptoms associated with trichomoniasis?
* itching
* burning
* foul green-yellow discharge
96
True or False: A trichomoniasis infection must be cleared up before the delivery of a baby to prevent the baby from becoming infected?
* True
97
What flagellated protist is responsible for the STI trichomoniasis?
* *Trichomonas vaginalis*
98
What common sexually transmitted disease is *Trichomonas vaginalis* responsible for?
* Trichomoniasis
99
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
100
How would you diagnose someone with trichomoniasis?
* Observation of parasite in vaginal discharge, semen, or urine
101
The teatment, prevention, and control of trichomoniasis is inclusive of what?
* Antiparasite therapy
102
What method of movement does trichomoniasis use?
* Flagella
103
What sample from the human body would you find Trichomonas in?
* Swabs of the urogenital tract would contain the parasite
104
What is the most common way to become infected with Trichomoniasis?
* Sexual contact
105
What is blastomycosis?
* A systemic mycosis caused by *Blastomyces dermatitidis* (dimorphic fungus)
106
What organism causes blastomyces, a systemic mycosis (disease)?
*Blastomyces dermatitidis*
107
What are the three clinical forms of blastomycosis?
* Cutaneous
* Pulmonary
* Disseminated
108
What type of disease is blastomycosis?
* Airborne disease
109
How does *Blastomyces dermatitidis* cause cutaneous ulcers and abcesses?
* After lung inhalation spreads rapidly to skin causing cutaneous ulcers and abcesses
110
How would you diagnose blastomycosis?
* Serological tests
111
What types of treatment would you provide to treat blastomycosis?
* Amphotericin B/ other anti-fungal drugs for treatment
112
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
113
How would you diagnose coccidioidomycosis?
* Demonstration of spherule
114
What does the prevention of coccidioidomycosis involve?
* Prevention involves avoiding exposure to dust
115
What type of disease is Cryptococcosis?
* Airborne disease
116
What is cryptococcosis?
A systemic mycosis caused by yeast *Cryptococcus neoformans*
117
What yeast is responsible for the systemic mycosis cryptococcosis?
* *Cryptococcus neoformans*
118
What is the source of cryptococcosis?
* The source is dried pigeon droppings
119
Inhalation of *Cryptococcus neoformans* can lead to what complications?
* Serious disease including meningitis in immunocompromised (e.g., AIDS); mild or pneumonia-like in others
120
How would you diagnose someone with cryptococcosis?
* Detecting encapsulated yeast in clinical specimen
121
True or False: Histoplasmosis is an airborne disease?
True
122
True or False: Histoplasmosis is a common lung disease?
True
123
Histoplasmosis, a common lung disease, is caused by what pathogen?
*Histoplasma capsulatum* (dimorphic)
124
What systemic mycoses does *Histoplasma capsulatum* cause?
Histoplasmosis (a common lung disease)
125
How is histoplasmosis transmitted?
* Inhalation of airborne micronidia in bird droppings
* converts to yeast phase in body; flu-like illness
* only rarely becomes disseminated
126
How would you prevent/control for Histoplasmosis (common lung disease)
* Prevented/ controlled by wearing protective clothing in endemic areas and by soil contamination
127
What problem/complication does Tinea capitis cause?
* Infection of scalp hair
128
What problem/complication does Tinea pedis cause?
* Athlete's foot
129
What problem/complication does Tinea unguium cause?
* Infection of the nailbed
130
What problem/complication does Tinea cruris cause?
* Jock itch
131
*Aspergillus Fumigatus* and *A. flavus* can cause what disease?
* Aspergillosis
132
Aspergillosis is usually caused by what pathogen?
* Usually caused by *Aspergillus fumigatus*
* Also caused by *A. flavus*
133
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
134
How is the diagnosis of Aspergillosis made?
* By examination of pathological specimens or by isolation and characterization of fungus
135
How would you treat Apergillosis?
* Treament with antifungal drugs; treat underlying disease
136
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
137
True or False: Candidiasis can not be spread through sexual contact?
* False, Candidiasis **can** be spread through sexual contact
138
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
139
True or False: *Candida albicans* or *C. glabrata* are kept in check by the presence other normal microbiota?
True
140
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
141
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
142
Oropharyngeal candidiasis (thrush)?
* Commmon disease of newborns, denture wearers, and those on steroid therapies
143
Paronychia and onychomycosis?
* Associated with *Candida* infections of the subcutaneous tissues of digits and, nails, respectively
* usually result from continued immersion of hands
144
Intertriginous candidiasis?
* Involves axillae, groin, and skin folds
145
Napkin (diaper) candidiasis?
* Found in infants whose diapers are not changed frequently
146
Candidal vaginitis?
* Occurs when lactobacilli are depleted
147
Balanitis (a type of candidiasis)?
* Transmission to males during intercourse
* infection of glans penis; occurs primarily in uncircumcised men
148
What is the diagnosis for candidiasis?
* Diagnosis of candidiasis is difficult
149
What is the treatment, prevention and control of candidiasis inclusive of?
* No satisfactory treatment
* anti-fungals used for cutaneous lesions and systemic candidiasis
150
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
151
*Micrsopora* are responsible for what emerging infectious disease, found mostly in HIV patients?
* Microsporidiosis
152
What are some reservoirs for microsporidia?
* Domestic and feral animals are reservoirs for species that infect humans
153
True or False: Microsporidia produce highly resistant spores?
* True
154
How does one become infected with microsporidia?
Infection of host cells occurs when microsporidia extrudes polar tubule from within the spore
155
What are the symptoms of a microsporidia infection (Microsporidiosis)?
* Wide variety including hepatitis, pnuemonia, skin lesions, diarrhea, weight loss, and wasting syndrome
156
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
157
What is the treatment, prevention, and control of microsporidia infection (microsporidiosis) inclusive of?
* Some treatment success with antifungal drugs
158
This fungus is found in the lungs of a variety of mammals?
* *Pneumocystis jiroveci* (previously *carinii*) causes *Pnuemocystis* pneumonia which is indicated as PCP
159
*Pneumocystis* pneumonia is casued by what pathogen?
*Pneumocystis jiroveci* (previously *carinii*)
160
*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
161
What is the laboratory diagnosis for *Pneumocystis* pneumonia (PCP)?
* Microscopic observation of organisms in lung tissue or PCR
162
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
