Parasitology Flashcards
(136 cards)
1
Q
Life stages of a parasite include:
A
- Egg
- Immatures = larvae (nymph)
- Adults
2
Q
Host in which parasite reproduces
A
Definitive host
3
Q
Host in which development occurs, but no reproduction
A
Intermediate host
4
Q
How are intestinal parasites diagnosed?
A
Fecal specimen
5
Q
How are blood parasites diagnosed?
A
Thick and thin specimen slides
Thick for finding the parasite
Thing for IDing the parasite
6
Q
How are tissue parasites diagnosed?
A
Biopsy
7
Q
What parasite causes amebic dysentery?
A
Entamoeba histolytica
8
Q
What are the life stages of entamoeba histolytica?
A
Trophozoite - the active feeding stage
Cyst - resistant to environment and infective form
9
Q
How is entamoeba histolytica transmitted?
A
Cysts are ingested in contaminated water or food, especially if night soil used.
Can also be vectored by flies
10
Q
The cysts of entamoeba histolytica excyst where in the host?
A
Intestines, causing bloody diarrhea, but the trophozoite can enter the blood and move to the liver causing hepatic amebiasis (pus in liver)
11
Q
What parasite causes beaver fever?
A
Giardia lamblia
12
Q
What are the life stages of giardia lamblia?
A
Trophozoite - active feeding stage
Cyst - resistant to environment and infective form
13
Q
How is giardia lamblia transmitted?
A
Cysts are ingested in contaminated water, especially if beaver habitat is close by because they are reservoirs
14
Q
The cysts of giardia lamblia excyst where in the host?
A
They excyst in the intestines and cover the intestinal wall, interfering with fat absorption and causing diarrhea
15
Q
What are the flagellated Protozoa that are pathogenic to humans?
A
- giardia lamblia
- trichmonas vaginalis
- trypanosoma brucei
- trypanosoma cruzi
- leishmania donovani
- leishmania tropica
- leishmania braziliensis
16
Q
What are the life stages of trichomonas vaginalis?
A
No cyst stage, only trophozoite
17
Q
How is trichomoniasis transmitted?
A
The trophozoite of trichomonas vaginalis is passed sexually, causing urogenital infection
18
Q
What is characterized by a “strawberry cervix”, intense itching and copious discharge from a urogenital infection?
A
Trichamoniasis
19
Q
African sleeping disease is caused by what flagellated Protozoa
A
Trypanosoma brucei
20
Q
What is the vector for trypanosoma brucei?
A
Tse Tse Fly
21
Q
What is the reservoir for trypanosoma brucei?
A
Big game animals
22
Q
What are the life stages of the trypanosome parasites (brucei and cruzi)?
A
The Protozoa form called trypanosome, there is no cyst stage
23
Q
Describe the pathology of African sleeping sickness (AKA African trypanosomiasis)
A
Trypanosomes invade blood, lymph nodes, spleen and CSF of host. The invade the tissue spaces, not the cells themselves. Causes mental dullness, sleepiness, coma and death
24
Q
What causes Chagas’ disease?
A
Trypanosoma cruzi
25
What is the vector for trypanosoma cruzi?
The reduviid bug (kissing bug)
26
How is trypanosoma cruzi transmitted?
The reduviid bug vectors the parasite, feeds on the host and infects the wound through defecation
27
The small red nodule at the bite site of a reduviid bug that is vectoring trypanosoma cruzi is called ____.
Chagoma
28
What disease caused by trypanosoma cruzi mostly affects children and causes anemia, nervous disorders, muscle and bone pain, heart failure within 3-4 weeks?
Acute Chagas’ disease
29
What disease caused by trypanosoma cruzi is virtually asymptomatic for years and then suddenly causes death due to heart failure?
Chronic Chagas’ disease
30
What are the life stages of the leishmania parasites (donovani, tropica and braziliensis)?
The life stage is the Protozoa form and there is no cyst
31
What flagellated Protozoa causes visceral leishmaniasis (AKA Kala-azar)?
Leishmania donovani
32
What is the vector for all leishmania species (donovani, tropica, braziliensis)?
Sand fly
33
What is post-kala azar dermal leishmanoid?
A granulomatous reaction on the skin that occurs 2-3 years after being treated for leishmania donovani
34
Visceral leishmaniasis (AKA kala azar) affects what organs?
It causes enlarged liver and spleen, leading to wasting and eventual death if untreated
35
What causes cutaneous leishmaniasis (AKA oriental sore)?
Leishmania tropica, a flagellated Protozoa
36
What disease is characterized by a red papule from sandfly bite that is slow to heal and scars?
Cutaneous leishmaniasis AKA oriental sore
37
What causes mucocutaneous leishmaniasis (AKA espundia)?
Leishmania braziliensis
38
What disease is characterized by lesions in the junction of the pharynx that results in a break down of the palate of the nose and mouth?
Mucocutaneous leishmaniasis AKA espundia
39
What causes ciliary dysentery?
Balantidium coli
40
What are the life stages of balantidium coli?
- large ciliated trophozoite
| - cyst
41
How is balantidium coli transmitted?
Water contaminated with pig feces
42
What are the symptoms associated with ciliary dysentery caused by infection with balantidium coli, a ciliated protozoa?
Abdominal pain, watery and bloody stool
43
What are the genera included in the sporozoa group of parasitic protozoa?
- plasmodium
- toxoplasma
- babesia
- cryptosporidium
44
What genera of sporozoa cause malaria?
Plasmodium
45
What are the life stages of plasmodium?
- Sporozoite is the infectious form that is released from mosquito into human host and then goes to the liver
46
In the vertebrate host, what are the two cycles that occur for the sporozoite plasmodium?
- exoerythrocytic stage occurs in the liver
| - erythrocytic stage occurs in RBCs
47
In the erythrocytic stage of plasmodium infection, merozoites produce a waste product called ______ that causes lysis of RBCs leading to anemia and jaundice.
Malarial pigment
48
What is the vector for all plasmodium species (vivax, malariae, falciparum, ovale)?
Anopheles mosquito
49
Which species of plasmodium is the most common cause of malaria?
Plasmodium vivax
50
Red blood cells infected with what parasite have unique pink dots called Schuffner’s dots?
Plasmodium vivax
51
Malaria with a characteristic relapsing fever that occurs every other day is caused by what parasite?
Plasmodium vivax, a sporozoa
52
What species of plasmodium is characterized by the asexual form appearing as a rosettes in the infected RBCs and causes fever that occurs in 72 hour pattern?
Plasmodium malariae
53
Malaria caused by plasmodium malariae is also know as _______.
Quartan or malarial malaria
54
Malaria caused by plasmodium vivax is also called _______.
Benign tertian malaria
55
What species of plasmodium causes the most serious form of malaria?
Plasmodium falciparum
56
What parasitic infection is characterized by multiple sporozoite infecting one RBC creating “signet ring” formation?
Plasmodium falciparum
57
What parasite causes the form a malaria characterized by black water fever (intracascular hemolysis), kidney failure, mental decline, coma and death?
Plasmodium falciparum
58
What species of plasmodium is similar to plasmodium vivax but produces fewer merozoites and relapse of fever is common?
Plasmodium ovale
59
What is the definitive host for toxoplasma gondii?
Cats
60
What are the life stages of toxoplasma gondii?
- sporozoite are infectious form
| - contained within oocyst that is passed out in feces
61
What are the possible means of transmission for toxoplasma gondii?
- ingestion of undercooked meat that is infected
- infection of the oocyst from recalls contaminated hands or food
- transplacental
62
Infection with toxoplasma in immunocompetent persons is generally asymptomatic but in those with AIDs it can cause ______
Toxoplasmic encephalitis
63
Congenital toxoplasmosis results from an acute primary infection acquired by the mother during pregnancy. During which trimester is it most damaging and what does it cause?
- Infection during the 1st trimester is most damaging
| - causes blindness, encephalitis and mental retardation
64
What parasite is difficult to detect in water treatment, is resistant to chlorination and ingestion of the cyst causes watery diarrhea?
Cryptosporidium parvum
65
What is another name for roundworms?
Nematodes
66
What are the roundworms that are transmitted by ingestion of the ova?
- ascaris lumbricoides
- trichuris trichiura
- enterodius vermicularis
67
What is the largest nematode that parasitizes the human intestine?
Ascaris lumbricoides
68
What is the life cycle of ascaris lumbricoides?
Ova ingested => larva hatch in duodenum => move to lungs via blood vessels => molt and mature in lungs => larvae are coughed up and swallowed => develop into adult worm in small intestine => female produces 200,000 eggs daily that are passed in feces
69
The eggs of the escapism lumbricoides roundworm can stay viable in soil for how long?
Up to 3 years
70
What is the pathology of ascaris lumbricoides infections>
Some pulmonary symptoms during the lung stage but usually no acute symptoms until there is a high worm burden that may cause abdominal pain and intestinal or bile duct obstruction
71
What species of nematode is also known as the whip worm?
Trichuris trichiura
72
What is the life cycle of trichuris trichuria?
Eggs ingested => hatch in small intestine => larvae migrate to cecum and mature to adults => female produces 10,000 eggs daily that are excrete in feces
73
What is the pathology of trichuris trichiura (whip worm) infection?
Mostly asymptomatic, until there is a heavy worm burden and then it causes anemia from consumed blood cells, secondary infections from damaged epithelia, and prolapse of the rectum can occur
74
What is another name for the nematode, enterobius vermicularis?
Pinworm
75
Humans are considered to be the only hosts for which parasitic nematode?
Pinworm (enterobius vermicularis)
76
What is the life cycle of enterobius vemicularis?
Gravid female is nocturnal and migrates out of intestine to lay eggs on perianal skin at night => causes intense itching and eggs are transferred to fingernails and then ingested => larvae hatch in small intestine and migrate to colon where they mature into adult worm
77
What is a helminthic infection?
Infection with parasitic worm
78
What is the most common helminthic infection in the US, common in school or preschool children?
Enterobius vermicularis
79
What is the pathology of an enterobius vermicularis infection?
Frequently asymptomatic except perianal itching, especially at night, which may lead to secondary bacterial infection
Rarely invades female genital tract causing vulvovaginitis
80
What are the species of parasitic roundworm that are transmitted by direct penetration of infectious larvae?
- ancylostoma duodenale
- nectar americanus
- ancylostoma braziliense
- strongyloides stercoralis
81
What two species of roundworm are also known as the American hookworm?
Ancylostoma duodenale and necator americanus
82
What is the infective life stage form of ancylostoma duodenale and necator americanus?
Filaform
83
What is the life cycle of ancylostoma duodenale and necator americnus?
Adult female in small intestine lays eggs => excreted in feces => larva hatch and feed on bacteria in feces =>rhabditiform larva molts to filariform larva => filariform larva penetrates bare skin => moves to lungs => coughed up and swallowed
84
What is the pathology of infection with American hookworm (ancylostoma duodenale and necator americanus)
Possibly dermatitis or pulmonary symptoms in the early stages and anemia with malnutrition in the late stages
85
What is the dog and cat hookworm?
Ancylostoma braziliense
86
What is the life cycle of ancylostoma braziliense?
Larvae penetrate skin and wander because they cannot complete life cycle in humans
87
What is the pathogenesis of ancylostoma braziliense?
The larvae cannot complete their life cycle in humans so they cause visceral larval migrans which is a creeping eruption that causes intense itching and eosinophilia
88
What parasitic round worm alternates between free-living and parasitic forms?
Strongyloides stercoralis
89
What does ovoviviparous mean?
The eggs remain within the mother until they hatch or are about to hatch
90
What is the infectious for of strongyloides stercoralis
Filariform larvae
91
What is the lifecycle of strongyloides stercoralis?
Ovoviviparous female deposits eggs in small intestine => they hatch and are are excreted in feces or auto infect => can become free-living adults in soil or become infectious filariform larvae => larvae penetrate skin => move through blood to lungs => molt in lungs and are coughed up and swallowed
92
What are the main species of parasitic tissue roundworms?
- anisaka
- trichinella spiralis
- wuchereria bancrofti
- onchocerciasis vulvulus
93
The larvae of what parasite is found in the flesh of raw fish that can be transmitted to humans, producing intestinal obstructions, pain, nausea and vomitting?
Anisaka
94
What is the life cycle of trichinella spiralis?
Encrypted larvae are ingested => molt in intestines => adult female produces 100s of eggs => adult male and female die => larvae are carried via blood to muscle where they encyst => muscle tissue must be consumed for life cycle to complete => larvae calcify and die if not consumed => must be surgically removed
95
Humans are a dead end host for what parasitic roundworm whose larvae encyst in muscle, calcify and die?
Trichinella spiralis
96
What is the pathology of trichinella spiralis infection once they have encysted in muscle tissue?
- facial edema, conjunctivitis, fever, myalgia, rashes and blood eosinophilia
- occasionally myocarditis, CNS involvement and pneumonitis that can be life threatening
97
Bancroftian filariasis is better know as _______.
Elephantiasis
98
How is bancroftian filiaris vectored?
Mosquito
99
What is the life cycle of wuchereria bancrofti, the filarial worm that causes elephantiasis?
Ovoviviparous female in lymph duct produce immature larvae known as microfilariae => lymph nodes obstruct and swell primarily in legs and scrotum
100
Why can blood draws of individuals with wuchereria bancrofti infection, sometimes be absent of the parasite?
The microfilariae (larvae) exhibit periodicity and are active only at night, so blood must be drawn at night
101
What parasite causes river blindness?
The filarial worm, Ochocerca volvulus
102
What is the vector for onchocerca volvulus?
Black fly, simulium
103
What is the life cycle of onchocerca volvulus?
Adult worms under the skin become encapsulated by host reactions => nodules form => female releases microfilariae that migrate through skin and eyes
104
Trichinella spiralis has low host specificity and can infect what species other than humans?
Bears, pigs, rats
105
What is the pathology of onchocerca volvulus?
Larvae migrate through skin causing inflammation or eyes causing blindness
106
Inflammed skin known as “lizard skin” is seen in the infection with what parasite?
Onchocerciasis volvulus
107
What is another name for flat worms?
Platyhelminthes
108
What is another name for trematodes?
Flukes
109
What is another name for cestodes?
Tapeworms
110
What are the main species of parasitic trematodes/flukes, all of which have snails as their intermediate hosts to excrete cercariae?
- fasciola hepatica
- clonorchis sinesis
- fasciolopsis buski
- schistosomes (mansoni, haematobium, japonicum)
111
What parasitic trematode causes liver damage as well as bile duct inflammation, pain, chills and fever?
Fasciola hepatica, AKA the liver fluke
112
What is the life cycle of fasciola hepatica?
Adult flukes live in bile duct => eggs are passed out of liver with bile and excreted in feces => larvae penetrate snails => motile larvae leave snails and encyst as metacercariae on water plants => metacercriae are ingested => migrate to liver
113
The Chinese liver fluke, also known as ______, matures in the bile ducts and produce thousands of eggs daily for at least 6 months.
Clonorchis sinensis
114
What is the life cycle of clonorchis sinensis?
Eggs excreted in feces => hatch in water => larvae penetrate snails => cercariae leave snail to penetrate fish => metacercariae encyst in fish flesh => humans ingest metacercaria with raw fish
115
The giant intestinal fluke is also called ______
Fasciolopsis buski
116
What is the life cycle of fasciolopsis buski?
Eggs excrete in feces and infect water => larvae penetrate snail => cercariae move to plants => metacercariae encyst under leaves => humans or pigs ingest
117
What parasite are you most at risk of ingesting when you eat water chestnuts?
The metacercariae of fasciolopsis buski
118
Schistosomes are also known as ________.
Blood flukes
119
Most flukes are monoecious, meaning each fluke has both male and female reproductive parts. The exception is ________, that are dioecious, with separate male and female worms.
Schistosomes including mansoni, haematobium, japonicum
120
All three species of schistosomes (mansoni, haemotobium, japonicum) have similar life cycles. What are they?
Male and female live in blood vessels => release eggs that travel to intestine or bladder => excreted in urine or feces => eggs hatch in water => penetrate snails => snails excrete infective cercariae => cercaria penetrate skin of host => mature and reside in veins for 20-30 years
121
What is the pathology of infection with scistosomes (mansoni, haemotobius, japonicum)?
- Dermatitis, known as swimmer’s itch, from penetration by cercaria
- splenomegaly and ascites from eggs accumulating can causing an immune response
- eosinophilia
122
WHat are the main species of tapeworms that infect humans?
- taenia saginata/beef tapeworm
- taenia solium/ pork tapeworm
- diphyllobothrium latum/ fish tapeworm
- echinococcus granulosus
123
Adult tapeworms live in the small intestine of the human by attaching to the intestinal wall by means of a head called a _____.
scolex
124
The body of the tapeworm is composed of segments called ______, each of which contains a set male and female organs that produce eggs.
proglottids
125
Which species of tapeworm is also known as the beef tapeworm?
Taenia saginata
126
What species of tapeworm is also known as the pork tapeworm?
Taenia solium
127
What species of tapeworm is also known as the fish tapeworm?
Diphyllobothrium latum
128
What is the life cycle of taenia saginata?
Cattle consume gravid proglottids or eggs in contaminated feed => eggs hatch and larvae migrate to muscle => larvae encyst in muscles as cysticerci => humans consume undercooked beef
129
What is the pathology of taenia saginata?
Mild abdominal symptoms
| Passage of proglottids in feces
130
What is the life cycle of taenia solium?
Same as T saginata, except the intermediate host is a pig instead of cow.
131
What is the pathology of infection with taenia solium?
Infective larvae migrate into muscle or tissue of human host and develop into cysticerci
Usually this does not cause symptoms but if they develop in the eye or brain, can cause meningitis, visual disturbance and acute inflammatioin
132
What is the life cycle of diphyllobothrium latum?
Eggs eliminated in feces => eggs hatch in water => larvae called coracidium are ingested by copepods => fish ingest copepods => larvae mature to sporangum and encyst in fish muscle => humans ingest undercooked meat
133
What is the pathologies associated with diphyllobothrium latum infection?
- Vitamin B12 deficiency and associated anemia
| - abdominal discomfort, diarrhea, vomiting, and weight loss
134
What is the life cycle of echinococcus granulosus?
Adult worms infect canines and release eggs in small intestines => eggs released in feces and ingested by sheep, cattle, pigs => humans are accidental host by contact with infected dog => larvae move into liver and lung => form hydatid cyst
135
The hydatid cyst, as seen in echinococcus granulosus infection, contains infectious worms called _____>
Hydatid sand
136
What is the pathology of echinococcus granulosus?
Asymptomatic for years until enlarging hydatid cyst causes symptoms in affected organ (liver, lungs, brain, bone heart)
The cyst can also rupture and produce fever, eosinophilia and anaphylactic shock
