Miscellaneous Protozoa Flashcards
1
Q
What are the four groups mentioned?
A
- Ciliates
- Sporozoa
- Blastocystis hominis
- Pneumocystis jiroveci
2
Q
What type of movement do parasites in the Ciliates group use?
A
Hair-like cytoplasmic extensions
3
Q
What is the human pathogen associated with the Ciliates group?
A
Balantidium coli
4
Q
Which subclass does Sporozoa belong to?
A
Coccidia
5
Q
What type of species does the subclass Coccidia include?
A
Intestinal and tissue dwelling species
6
Q
What class does Blastocystis hominis belong to?
A
Blastocystea
7
Q
How is Blastocystis hominis classified?
A
Considered a yeast
8
Q
What is Pneumocystis jiroveci now considered as?
A
A fungi
9
Q
What is the scientific name of the organism that causes balantidiasis?
A
Balantidium coli
Balantidiasis is an intestinal infection caused by this protozoan.
10
Q
What is the largest protozoan known to humans?
A
Balantidium coli
This organism is notable for being the largest protozoan affecting humans.
11
Q
What is the length size range of Balantidium coli trophozoites?
A
28-152 micrometers, average: 35-50 micrometers
Trophozoites are the active, feeding stage of the organism.
12
Q
What is the width size range of Balantidium coli trophozoites?
A
22-123 micrometers, average: 40 micrometers
The size can vary significantly within this range.
13
Q
What type of motility does Balantidium coli exhibit?
A
Rotary, boring motility
This motility allows the organism to move through its environment.
14
Q
What are the two types of nuclei found in Balantidium coli?
A
- Macronucleus (kidney shaped)
- Micronucleus (spherical)
These nuclei serve different functions in the organism’s life cycle.
15
Q
How many contractile vacuoles can Balantidium coli have?
A
One or two
Contractile vacuoles are involved in osmoregulation.
16
Q
What structures may be found within the cytoplasm of Balantidium coli?
A
- Food vacuoles
- Bacteria
These components are essential for the organism’s nutrition.
17
Q
What surrounds the organism Balantidium coli?
A
Layer of cilia
Cilia aid in locomotion and feeding.
18
Q
What is the size range of Balantidium coli cysts?
A
43-66 micrometers in length, averaging 52-55 micrometers
Cysts are the dormant stage of the organism.
19
Q
What key structures do Balantidium coli cysts contain?
A
- Macronucleus
- Micronucleus
These nuclei are important for the survival of the organism in a dormant state.
20
Q
How many contractile vacuoles can be found in Balantidium coli cysts?
A
One or two
Similar to trophozoites, cysts can also have contractile vacuoles.
21
Q
What type of wall do Balantidium coli cysts have?
A
Double cyst wall
This structure helps protect the cyst in harsh environments.
22
Q
What is found between the two cyst walls of Balantidium coli?
A
Row of cilia
These cilia may play a role in the organism’s life cycle.
23
Q
True or False: Mature Balantidium coli cysts tend to retain their cilia.
A
False
Mature cysts tend to lose cilia as they develop.
24
Q
What is the laboratory diagnosis method for Balantidium coli?
A
Wet preparations and permanent stains
This involves examining stool specimens for the presence of trophozoites and cysts.
25
What may be required to ensure an accurate laboratory test report for B.coli?
Multiple stool samples
## Footnote
This is necessary to correctly determine the presence or absence of the parasite.
26
What is the infective form of Balantidium coli?
Cysts
## Footnote
These are found in suspicious stool samples.
27
What initiates human infection of Balantidium coli?
Ingestion of infective cysts in contaminated food or water.
28
Where do trophozoites primarily reside and feed in the human body?
Cocal region, terminal portion of the ileum, lumen, mucosa, and submucosa of the large intestine.
29
How do trophozoites of Balantidium coli multiply?
By transverse binary fission.
30
What occurs during the encystation phase of Balantidium coli?
Cysts mature and become the infective form for transmission into new hosts.
31
What is a key difference between Balantidium coli and E. histolytica in terms of multiplication?
B.coli multiplication does not occur in the cyst phase.
32
What is the asymptomatic carrier state in relation to Balantidium coli?
Some patients are carriers of B.coli and remain asymptomatic.
33
What are the clinical symptoms of balantidiasis?
Symptoms range from mild colitis and diarrhea to full-blown balantidiasis.
34
What severe symptoms can occur in acute Balantidium coli infection?
15 liquid stools daily containing pus, mucus, and blood.
35
What are some potential complications of chronic Balantidium coli infection?
Tender colon, anemia, cachexia, and occasional diarrhea alternating with constipation.
36
Which areas can Balantidium coli invade besides the intestines?
Lungs, pleura, liver, mesenteric nodes, and neurogenital tract.
37
What is the typical incidence of human infections with Balantidium coli?
Very low.
38
Through what routes is Balantidium coli transmitted?
Oral-fecal and person-to-person routes.
39
What is considered a significant source of Balantidium coli infection?
Water contaminated with feces from pigs.
40
What is the medication of choice for treating Balantidium coli infection?
Oxytetracycline (Teramycin).
41
What is an alternative medication for Balantidium coli treatment?
Metronidazole (Flagyl).
42
What are key prevention and control measures for Balantidium coli?
Personal hygiene, proper sanitary conditions, and precautions when handling pigs.
43
What does the name Balantidum mean?
Little bag.
44
What percentage of pigs are estimated to harbor B.coli?
63% to 91%.
45
Does Balantidum suis cause human infections?
No, it does not appear to cause human infections.
46
What has been suggested about human resistance to Balantidium coli?
Humans have a relatively high natural resistance to this organism.
47
What is the shape and size of Isospora belli oocysts?
Oval-shaped, transparent; 25-30 micrometers in length and 10-15 micrometers in width
## Footnote
Oocysts have a smooth, colorless, two-layered cell wall.
48
What are the two main components of the Isospora belli oocyst?
Sporoblast and sporocyst
## Footnote
Sporoblast is an immature sac; sporocyst contains four sporozoites.
49
What is the specimen of choice for the laboratory diagnosis of Isospora belli?
Fresh stool and duodenal contents
## Footnote
These samples may contain immature, partially mature, and/or fully mature oocysts.
50
What staining methods are recommended for confirming Isospora belli oocysts?
Modified acid-fast stain and auramine-rhodamine stain
## Footnote
Modified acid-fast stain is recommended as a permanent stain.
51
What initiates human infection of Isospora belli?
Ingestion of infective mature (sporulated) oocysts in contaminated food or water
## Footnote
There is no intermediate host.
52
What occurs after the excystation of the oocyst in the small intestine?
Sporozoites emerge
## Footnote
This begins the life cycle of the organism.
53
What type of reproduction occurs in the cells of the intestinal mucosa for Isospora belli?
Asexual reproduction (schizogony)
## Footnote
This process results in the formation of merozoites.
54
What are the two types of gametocytes formed during sexual reproduction in Isospora belli?
Macrogametocytes and microgametocytes
## Footnote
These are formed in the intestinal area.
55
What are some clinical symptoms of isosporiasis?
Weight loss, chronic diarrhea, abdominal pain, anorexia, weakness, malaise, and eosinophilia
## Footnote
Symptoms can range from mild gastrointestinal issues to severe dysentery.
56
True or False: Isospora belli infections are always symptomatic.
False
## Footnote
Infections can be asymptomatic and self-limited.
57
What may Charcot-Leyden crystals in stool samples indicate?
Eosinophilia
## Footnote
These crystals may form in response to eosinophilia.
58
What is a characteristic of the stool produced during severe Isospora belli infection?
Foul-smelling, pale yellow, and loose consistency
## Footnote
Increased fecal fat levels are also observed.
59
What is the morphology of mature oocysts of Sarcocystis?
Oval and transparent with two sporocytes, average length 10-18 micrometers, each sporocyst has four sausage-shaped sporozoites, clear colorless double-layered cell wall
60
What is the specimen of choice for the recovery of Sarcocystis organisms?
Stool
61
In what preparations are mature oocysts typically seen?
Wet preparations
62
How can sporocytes appear in laboratory diagnosis?
Singly or in pairs that appear to be cemented together
63
What routine histologic methods can be used in Sarcocystis identification?
Methods to identify the sarcocyst stage from human muscle samples
64
How can human infection with Sarcocystis be initiated?
1. Ingesting uncooked pig or cattle meat infected with sarcocysts 2. Accidentally swallowing oocysts from stool sources of animals other than cattle or pigs
65
What is the role of humans in the Sarcocystis life cycle?
Humans can be the definitive or intermediate host
66
What occurs during gametogony in the Sarcocystis life cycle?
Gametogony occurs in human intestinal cells, leading to the development of oocysts and release of sporocysts
67
What are some clinical symptoms of Sarcocystis infection?
Fever, severe diarrhea, weight loss, abdominal pain, muscle tenderness
68
What is the frequency of Sarcocystis infections?
Relatively low, but distribution is worldwide
69
What is the treatment for Sarcocystis infection?
Trimethoprim + Sulfamethoxazole or pyrimethamine + sulfadiazine
70
What is a key prevention method for Sarcocystis infection?
Adequate cooking of beef and pork
71
True or False: Humans are the definitive host in the Sarcocystis life cycle.
True
72
Fill in the blank: Proper care and disposal of animal stool is important because humans serve as the _______.
intermediate host
73
What is the size range of Cryptosporidium parvum oocysts?
4-6 micrometers
## Footnote
Oocysts are roundish and often confused with yeast due to their thick cell wall.
74
What do mature oocysts of Cryptosporidium parvum consist of?
Four small sporozoites
## Footnote
Mature oocysts may also contain one to six dark granules.
75
What is the average size of schizonts and gametocytes?
2-4 micrometers
76
What are the components found within schizonts?
Four to eight merozoites, microgametocytes, and macrogametocytes
77
What is the specimen of choice for the recovery of Cryptosporidium oocysts?
Stool
78
Which stains can be used to visualize Cryptosporidium oocysts?
Iodine, modified acid fast stain, and formalin-fixed smears stained with Giemsa
79
What stool concentration techniques are effective for recovering Cryptosporidium?
Modified zinc sulfate flotation and Sheather’s sugar flotation
80
What is the typical route of infection for Cryptosporidium parvum?
Ingestion of mature oocysts
81
What happens to sporozoites after excystation?
They emerge in the upper gastrointestinal tract
82
What are the two forms of oocysts in Cryptosporidium parvum?
Thin-shelled version and thick-shelled version
83
What symptoms are associated with cryptosporidiosis in healthy individuals?
Self-limiting diarrhea lasting approximately 2 weeks, fever, nausea, vomiting, weight loss, abdominal pain
84
What are the severe symptoms of cryptosporidiosis in immunocompromised individuals?
Severe diarrhea, malabsorption, death
85
What is the primary method of transmission for Cryptosporidium parvum?
Water or food contaminated with infected feces and person-to-person transmission
86
Who are the individuals at risk for Cryptosporidium infection?
* Immunocompromised individuals
* Children in tropical areas
* Children in daycare centers
* Animal centers
* Travelers
87
What treatment has shown promise for ridding the host of Cryptosporidium?
Spiramycin
88
What are some prevention and control measures for Cryptosporidium?
* Proper treatment of water and supplies
* Using gloves and a lab gown
* Proper handwashing
* Properly disinfecting potentially infected equipment
89
What animal species were first associated with Cryptosporidium spp?
Poultry and cattle
90
What is C.parvum recognized as the agent responsible for?
Neonatal diarrhea in calves and lambs
91
What is the size range of the vacuolated form of Blastocystis hominis?
5-32 micrometers; average is 7-20 micrometers
92
What structure consumes 90% of the cell in Blastocystis hominis?
Vacuole
93
What is the appearance of the cytoplasm in Blastocystis hominis?
Appears as a ring around the periphery
94
How many nuclei can be found in the cytoplasm of Blastocystis hominis?
Two or four
95
What is the specimen of choice for the recovery of Blastocystis?
Stool
96
What color do the nuclei appear in iodine wet preparations of Blastocystis hominis?
Light yellow
97
How does the central vacuole of Blastocystis hominis appear in iodine wet preparations?
Clear and transparent
98
What does the peripheral cytoplasm stain like in permanent stain preparations of Blastocystis hominis?
Nuclei typically stain dark
99
What may lead to a false-negative result when diagnosing Blastocystis hominis?
Saline, like water, usually lyses this organism
100
How does Blastocystis hominis reproduce?
By sporulation or binary fission
101
What are common clinical symptoms of Blastocystis hominis infection?
* Diarrhea
* Vomiting
* Nausea
* Fever
* Abdominal pain
* Cramping
102
In what regions do epidemics of Blastocystis hominis occur?
Subtropical countries, including Saudi Arabia and British Columbia
103
What is the recommended treatment for Blastocystis hominis infection?
Iodoquinol or metronidazole
104
What are key prevention measures for Blastocystis hominis?
* Proper treatment of fecal material
* Hand washing
* Proper handling of food and water
105
What was the initial classification of Blastocystis hominis before being identified as a protozoan parasite?
Considered an algae, then as a harmless intestinal yeast
106
What type of organism is Cyclospora cayetanensis?
An intestinal coccidial organism
107
What is the size of the oocysts shed by infected patients of Cyclospora cayetanensis?
7-10 micrometers in diameter
108
How many sporocysts does Cyclospora cayetanensis form upon maturation?
Two sporocysts
109
What allows the sporocysts of Cyclospora cayetanensis to become visible in the lab?
Addition of 5% potassium dichromate
110
What microscopy methods are preferred for examining Cyclospora cayetanensis?
Phase contrast or bright field microscopy
111
What does modified acid-fast stain detect in Cyclospora cayetanensis?
Oocysts
112
What is the first step in the life cycle of Cyclospora cayetanensis?
Ingestion of oocyst
113
What is a notable clinical symptom of Cyclospora cayetanensis infection?
Longer duration of diarrhea compared to Cryptosporidiosis
114
Where is Cyclospora cayetanensis commonly reported?
* US
* Canada
* Lima, Peru
* Nepal and other parts of Asia
115
What is a key prevention measure for Cyclospora cayetanensis?
Properly treating water prior to use
116
What are Microsporidia?
A group of spore-forming unicellular parasites known to cause infections in humans and animals.
## Footnote
Microsporidia infections are particularly noted in immunocompromised individuals, such as those with AIDS.
117
Which genera of Microsporidia are known to cause human disease?
Three out of five genera known to cause human disease have been reported in patients suffering from AIDS.
## Footnote
The most well-known member is Enterocytozoon bieneusi.
118
What is the most well-known member of Microsporidia?
Enterocytozoon bieneusi
## Footnote
It is associated with enteritis.
119
What severe infections are associated with Encephalitozoon and Pleistophora in AIDS patients?
Severe tissue infections.
## Footnote
These infections can lead to significant morbidity.
120
What type of infections can Microsporidium cause?
Corneal infections and infections by Nosema.
## Footnote
Corneal infections can lead to visual impairment.
121
What is the size range of Microsporidia spores?
1 to 5 micrometers.
## Footnote
These spores are notably small and can be challenging to detect.
122
What characteristic do Microsporidia spores have?
Equipped with extruding polar filaments (tubules).
## Footnote
These filaments are used to inject sporoplasm into host cells.
123
What is the first step in the life cycle of Microsporidia?
Human infection is initiated when the infective spores inject sporoplasm into a host cell.
124
What laboratory techniques can be used for the diagnosis of Microsporidia?
Multiple techniques including:
* Serologic tests
* Cell culture
* Staining methods
* Thin smears stained with trichrome or acid-fast stain
* Giemsa-stained biopsy material and fecal concentrate specimens
* Transmission electron microscopy.
## Footnote
Each technique has specific applications and sensitivities for different species.
125
What clinical symptoms are associated with Microsporidial infection?
Enteritis, keratoconjunctivitis, myositis, and rarely peritonitis and hepatitis.
126
In which patient population are Microsporidia infections most commonly reported?
Patients with AIDS.
## Footnote
However, cases in individuals with normal immune systems have also been described.
127
What is the recommended treatment for Enterocytozoon bieneusi infection?
Albendazole.
## Footnote
Oral fumagillin is an alternative treatment.
128
What treatment is recommended for Nosema infection?
Albendazole plus fumagillin eye drops.
129
True or False: Microsporidia can be transmitted through urine.
True.
130
Fill in the blank: Microsporidia spores may be ingested by a _______.
[carnivorous animal].
131
What is Toxoplasma gondii?
A protozoan parasite responsible for toxoplasmosis.
132
What are the three types of toxoplasmosis?
* Toxoplasmosis
* Congenital toxoplasmosis
* Cerebral toxoplasmosis
133
What is the morphology of the oocyst of T. gondii?
Round to slightly oval, 10-15 micrometers long; 8-12 micrometers wide.
134
What are the two morphologic forms of trophozoites in T. gondii?
* Tachyzoites
* Bradyzoites
135
Describe tachyzoites.
Actively multiplying, crescent-shaped, ranging from 3-7 micrometers by 2-4 micrometers.
136
What characterizes bradyzoites?
Same appearance as tachyzoites but smaller, slow-growing, and form clusters inside host cells.
137
What is the primary means of diagnosing T. gondii infections?
Analyzing blood samples using serologic methods.
138
What is the recommended test for determining IgM antibodies in congenital infections?
Double-sandwich ELISA method.
139
What does the indirect hemagglutination (IHA) test determine?
IgG antibodies.
140
What is the definitive host of T. gondii?
Cat or other felines.
141
What are the intermediate hosts for T. gondii?
Rodents (mice or rats).
142
How can humans become infected with T. gondii?
* Contact with infected cat feces
* Ingestion of contaminated undercooked meat
* Transplacental infection
* Blood transfusion
143
What are general symptoms of toxoplasmosis?
* Mild symptoms
* Fatigue
* Lymphadenitis
* Chills
* Fever
* Headache
* Myalgia
144
What severe conditions can result from congenital toxoplasmosis?
* Hydrocephaly
* Microcephaly
* Intracerebral calcification
145
What percentage of infected infants results in death?
5-10%.
146
What are the common symptoms of cerebral toxoplasmosis in AIDS patients?
* Headache
* Fever
* Altered mental status
* Lethargy
* Focal neurologic deficits
* Brain lesions
* Convulsions
147
What is the estimated percentage of the population infected with T. gondii in the US?
15-20%.
148
What is the treatment of choice for symptomatic cases of T. gondii?
Trisulfa pyrimidines and pyrimethamine (Daraprim).
149
What are some prevention and control measures for T. gondii?
* Avoid contact with cat feces
* Handwashing
* Protective covers over sandboxes
* Thoroughly cooking meat
* Keeping cats away from infective rodents
150
Fill in the blank: T. gondii cysts may contain as few as _____ and to as many as several thousand bradyzoites.
50
151
True or False: Tachyzoites migrate to various tissues, including the brain, where they form cysts filled with bradyzoites.
True
152
What is the size range of T. gondii cysts?
12-100 micrometers.
153
What is the most commonly seen form of Pneumocystis jiroveci?
Trophozoites
## Footnote
Trophozoites are simple ovoid and ameboid organisms measuring 2 to 4 micrometers with a single nucleus.
154
What is the size range of cysts of Pneumocystis jiroveci?
4 to 12 micrometers
## Footnote
Cysts contain 4 to 8 intracystic bodies and can be arranged in a rosette shape or scattered.
155
What specimen types can be submitted for the diagnosis of Pneumocystis jiroveci?
Sputum, bronchoalveolar lavage, tracheal aspirate, bronchial brushings, lung tissue
## Footnote
These specimens are used for laboratory diagnosis.
156
Which staining methods are used for diagnosing Pneumocystis jiroveci?
Giemsa stain, iron hematoxylin stain, Gomori’s methenamine silver nitrate stain, monoclonal fluorescent stain
## Footnote
These stains are helpful in organism identification and histologic procedures.
157
What is known about the life cycle of Pneumocystis jiroveci?
Still considered unknown
## Footnote
It is presumed that P. jiroveci resides in alveolar spaces, with mature cysts rupturing to produce trophozoites.
158
What are the clinical symptoms of Pneumocystis pneumonia in immunosuppressed individuals?
Nonproductive cough, fever, rapid respirations, cyanosis
## Footnote
These symptoms are particularly severe in AIDS patients.
159
What is the leading cause of death in AIDS patients infected with Pneumocystis jiroveci?
Pneumocystosis
## Footnote
AIDS patients often also suffer from Kaposi’s sarcoma, a malignant skin disease.
160
What are the symptoms exhibited by infected malnourished infants?
Poor feeding, loss of energy, rapid respiration rate, cyanosis
## Footnote
Infected infants also show infiltrate on chest X-ray and breathing difficulties.
161
What is the primary cause of death in patients with Pneumocystis pneumonia?
Lack of proper oxygen and carbon dioxide exchange in the lungs
## Footnote
This condition leads to low P02 and normal to low PC02.
162
What regions have reported cases of Pneumocystis jiroveci infection?
US, Asia, Europe
## Footnote
The route of transmission is via pulmonary droplets through direct person-to-person contact.
163
What is the first-line treatment for Pneumocystis jiroveci infection?
Trimethoprim-sulfamethoxazole (Bactrim)
## Footnote
This is the preferred medication for treating Pneumocystis pneumonia.
164
What are alternative treatments for Pneumocystis jiroveci infection?
Pentamidine isethionate, cotrimoxazole
## Footnote
These are used when the first-line treatment is not suitable.
165
What preventive measures can be taken against Pneumocystis jiroveci infection?
Personal protection from droplets, using protective gear such as masks
## Footnote
These measures help reduce the risk of transmission.
