Parasitology I-II Flashcards
What are the protozoa that are spread human to human?
- Cryptosporidiosis
- Amebiasis
- Giardiasis
What are the protozoa that are spread animal to human?
- Cryptosporidiosis
- Toxoplasmosis
- Giardiasis
What are the vector borne protozoal diseases?
Malaria
Leishmanias
American Trypanosomiasis
African Trypanosomiasis
Malaria Vector
Anopheles Mosquito
Leishmanias Vector
Sand Fly
American Trypanosomiasis (Chagas Disease) Vector
Reduviid Bug
African Trypanosomiasis (Sleeping Sickness) Vector
Tsetse Fly
Plasmodium falciparum Dx
Blood smear
Leishmania tropica Dx
Skin scraping and biopsy
Trypanosoma cruzii Dx
Tissue biopsy or blood smear
Giardia lamblia Dx
Stool ova & parasite exam, immunofluorescence
Cryptosporidium Dx
Stool ova & parasite exam, immunofluorescence
Entamoeba histolytica Dx
Stool ova & parasite screen
Toxoplasmosis Dx
Tissue biopsy (brain, lymphnode, other) or serology
What are the protozoa indigenous to the US mainland?
- amebiasis
- giardiasis
- toxoplasmosis
- babesiosis pneumoocystis
- cryptosporidiosis
What is the prophylactic treatment for Plasmodium species?
Mefloquine or chloroquine
What is the prophylactic treatment for Pneumocystis jiroveci?
TMP/SMX in AIDS patients only
What is the prophylactic treatment for Toxoplasmosis gondii?
TMP/SMX in AIDS patients only
What is the life cycle of malaria in the mosquito?
Sporogony - gametocytes are formed which lead to a zygote then and oocyst and a sporozoite.
What is the life cycle of malaria in the human?
Schizogony - sporozoites are injected which can enter into one of two cycles:
- Exoerythrocytic - Liver -> the sporozoite will become a hepatic schizont which is then converted to a merozoite.
- Erythrocytic -> the sporozoite become a trophozoite then a RBC schizont before it is converted to a merozoite or a gametocyte before it is taken up by a mosquito again in a blood meal
Sporozoite
A motile sporelike stage in the life cycle of some parasitic sporozoans (e.g., the malaria organism) that is typically the infective agent introduced into a host.
Schizont
A mature sporozoite form that multiplies into thousands of merozoites
Merozoite
Merozoites infect red blood cells and then rapidly reproduce asexually. The red blood cell host is destroyed by this process, which releases many new merozoites that go on to find new blood-borne hosts. Merozoites are non-motile.
Trophozoite
It is the activated, intracellular feeding stage in the apicomplexan life cycle. After gorging itself on its host, the trophozoite undergoes schizogony and develops into a schizont, later releasing merozoites.
What is the RBC
Ag for P. vivax?
Duffy Ag
Which of the Plasmodium has widespread resistance to chloroquine?
P. falciparum
What Plasmodium are Schuffner’s dots indicative of?
P. vivax and P. ovale
What Plasmodium are electron dense knobs indicative of?
P. falciparum
What are some of the clinical manifestations of malaria?
• Chills, fever, headache, myalgias, nausea, splenomegaly
- cycles of fever with hemolytic anemia
• Anemia, thrombocytopenia
Which malaria species can persist in the liver and relapse in the blood after treatment?
P. vivax and P. ovale
Name the organs most severely affected in fulminant falciparum malaria.
– Cerebral malaria
– Renal failure
– Pulmonary edema
The sexual phase of the malaria life cycle in which gametocytes mature to the sporozoite is known as ________
Sporogony
What is the treatment for P. vivax/ovale?
Chloroquine + primaquine
What is the origin of Plasmodium knowlesi?
Monkeys
What is the vector for Babesiosis?
Ixodes scapularis – Tick
What are the clinical manifestations of babesiosis?
Majority have NO symptoms
– Fever
– Headache
– Fatigue
– Hemolytic anemia
What is characteristic on the blood smear of babesiosis?
Tetrads
What is the reservoir for Toxoplasma gondii?
Cats mainly. Also sheep, cattle and pigs.
What is the the greatest risk for passing Toxoplasma intrauterinely?
The greatest risk is when it is acquired by mother in 3rd trimester
Name the human cell in which babesia species are found.
RBCs
What is the treatment for babesiosis?
Atovaquone plus azithromycin
What can T. gondii cause in immunocompromised patients?
- encephalitis
- myocarditis
Where is Cryptosporidium found in a human host?
It carries out its life cycle in the intestinal villi
What are the clinical manifestation of Cryptosporidium?
– Explosive, watery diarrhea
– Abdominal pain
– Lasts one to two weeks
What is the difference in the infection of the immunocompromised with Cryptosporidium?
The diarrhea will continue relentlessly until immunity is restored
What is the reservoir for amebiasis?
Humans
What is characteristic of E. histolytica infection?
“Flask” ulcers
What is the transmission of amebiasis (E. histolytica)?
- cysts ingested (fecal oral)
- sex
What are the clinical findings in amebiasis?
– Asymptomatic
– Nonspecific diarrhea
– Dysentery (pain, fever, blood, pus)
– Spread – liver, pleural (lung), pericardium
What are the symptoms of Giardia infection?
Malabsorption type of diarrhea – Fat – Carbohydrate
What are the transmission mechanisms of Giardia?
Water, food, person-person, sex
What is a key feature of Trichomonas vaginalis on microscopy?
HIGHLY motile organism
What is the transmission mechanism of Trichomonas vaginalis?
Sex
What are the signs of T. vaginalis infection?
• Damages squamous mucosa of female genital tract
– Neutrophilic inflammatory reaction
– Petechial hemorrhages
What is the treatment for T. vaginalis infection?
– Metronidazole
– Tinidazole
ALSO TREAT MALE PARTNER
Which morphologic stage of leishmania is seen within macrophages in skin biopsy in the cutaneous form or in the liver or spleen in the visceral form?
Amastigote
What is the pathogenesis of leishmaniasis?
- Injected promastigotes opsonized with complement
- Taken up by macrophages; amastigotes multiply intracellularly
- Released to another cell or fly
Which morphologic stage of trypanosome circulates in the blood of people infected with Trypanosoma cruzi or Trypanosoma brucei gambiense?
Trypomastigote
What are some of the symptoms of African trypanosomiasis?
– Local lesion (chancre)
– Acute illness with fever
– Encephalopathy
What is Chagas’ Disease caused by? What is it AKA?
Trypanosoma cruzi.
American Trypanosomiasis
Which protozoan causes megaesophagus or megacolon?
Trypanosoma cruzi
The insect vector of Trypanosoma cruzi is the ___________
Reduviid Bug
The sexual phase of the life cycle of Toxoplasma gondii takes place in the _________________
Intestine of the cat
What are the clinical features of Chagas’ Disease?
– Acutefebirle
– Chronic heart failure, arrhythmia
– Megaesophagus and megacolon
What are the symptoms of Pneumocystis jiroveci infection?
– Fever
– Dry cough
– Severe dyspnea
• CXR Diffuse interstitial infiltrates
Is Pneumocystis jiroveci a protozoan?
No it is a fungus
How do humans acquire infection with Toxoplasma gondii?
Transmission by ingestion of oocysts (cat feces) or undercooked meat
What is the most common manifestation of toxoplasmosis in persons with AIDS?
Encephalitis
How is the specific diagnosis of Pneumocystis jiroveci pneumonia established?
See cysts in lung tissue and secretions with silver stain or DFA
Name the infective form of Entamoeba histolytica.
Trophoziote
The organ most commonly involved in extra-intestinal amebiasis is the ______________
Liver
The major site of infection with Giardia lamblia is ___________________________.
Intestines
Giardia lamblia causes diarrhea by
_____________
Fat/Carbohydrate Malabsorption
The clinical manifestation caused by cryptosporidium if it is acquired by healthy people is _________________
Explosive watery diarrhea
