Parasites: Babesia Microti and Leishmania Overview

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Questions and Answers

What type of examination should be included for a complete stool analysis?

Only a concentrated wet preparation

Only a permanent stained slide

A concentrated wet prep and a permanently stained slide (correct)

A combination of culture and PCR methods

Which of the following amebae is known to have a trophozoite form that can be preserved well in formalin?

Dientamoeba fragilis

Entamoeba polecki

Entamoeba histolytica (correct)

Entamoeba coli

What is a key characteristic of Dientamoeba fragilis?

It is not found in human stool specimens

It is a flagellate but resembles amebae (correct)

It primarily affects the respiratory tract

It has a cyst form

Which species is NOT considered a pathogen in the human intestinal tract?

Entamoeba coli Signup and view all the answers

What method may achieve sensitivity equal to or exceeding that of culture for detecting parasites?

PCR methods Signup and view all the answers

What type of organisms are classified as protozoa in the human intestinal tract?

Amebae, flagellates, ciliates, and coccidia Signup and view all the answers

What challenges may arise when using formalin-based preparations for stool examinations?

Inadequate preservation of trophozoites Signup and view all the answers

Which ameba does NOT have a cyst form?

Dientamoeba fragilis Signup and view all the answers

What is a distinguishing feature of P.ovale late-stage trophozoites compared to those of P.vivax?

They appear more compact. Signup and view all the answers

What evidence suggests chronic subclinical infections of Babesia microti may be common?

Some patients tested positive without clinical disease history. Signup and view all the answers

What is the nature of the spectrum of babesiosis as mentioned?

It varies from latent to severe symptomatic infection. Signup and view all the answers

Which group is at higher risk for severe outcomes from babesiosis?

Splenectomized or immunocompromised individuals. Signup and view all the answers

What method has been approved to detect Babesia microti in whole blood?

Nucleic acid test for detecting DNA. Signup and view all the answers

Which of the following statements is accurate regarding the treatment of asymptomatic infections?

They do not require treatment generally. Signup and view all the answers

What type of infections can B.microti cause according to the evidence?

Both subclinical and fulminant infections. Signup and view all the answers

What has been observed about symptomatic patients with B.microti infection?

Some may have the parasite for months. Signup and view all the answers

What type of lesions are commonly produced by Leishmania mexicana?

Ulcerative lesions in the earlobe Signup and view all the answers

Which organisms must amastigotes of Leishmania peruviana be differentiated from?

Toxoplasma gondii and Histoplasma capsulatum Signup and view all the answers

Which staining method does NOT typically stain Leishmania spp.?

Gomori methenamine silver (GMS) Signup and view all the answers

Where is the focus of cutaneous leishmaniasis primarily located?

Southern Texas Signup and view all the answers

What is a notable characteristic of amastigotes found in tissue sections?

They may appear smaller due to fixation shrinkage Signup and view all the answers

In what type of environment is Leishmania peruviana typically acquired?

In urban homes with domestic animals Signup and view all the answers

Which species of Leishmania is known to cause uta, a benign cutaneous lesion?

Leishmania peruviana Signup and view all the answers

Which feature is NOT associated with the amastigotes of Leishmania spp.?

Presence of a thick exocellular secretive coating Signup and view all the answers

What size range is typically observed for cysts of Entamoeba histolytica/E. dispar?

10–20 μm Signup and view all the answers

Which characteristic is NOT associated with the cysts of Entamoeba histolytica/E. dispar?

Presence of visible flagella Signup and view all the answers

How many nuclei are typically found in mature cysts of Entamoeba histolytica/E. dispar?

4 Signup and view all the answers

What type of disease has Dientamoeba fragilis been associated with?

Diarrheal disease Signup and view all the answers

What is a common observation of the cytoplasm in mature cysts of Entamoeba species?

Usually diffuse and concentrated in young cysts Signup and view all the answers

What type of chromatin is typically found in the nuclei of Entamoeba histolytica/E. dispar cysts?

Fine, uniform chromatin Signup and view all the answers

Which feature is characteristic of the karyosomal chromatin in Entamoeba histolytica/E. dispar?

Central with small, discrete granules Signup and view all the answers

Is there a unique population of Dientamoeba fragilis found exclusively in humans?

No, it shares populations with other species Signup and view all the answers

What is the usual size range of Entamoeba coli?

20–25 μm Signup and view all the answers

Which organism is characterized by coarse granular and vacuolated appearance?

Iodamoeba buetschlii Signup and view all the answers

What type of movement is typically associated with Endolimax nana?

Sluggish, usually nonprogressive Signup and view all the answers

Which organism has a distinct appearance with a large cluster of granules?

Dientamoeba fragilis Signup and view all the answers

Which of the following is true about the nuclei of Dientamoeba fragilis?

Only one nucleus is present in approximately 20% of organisms Signup and view all the answers

What is the size range classification for Iodamoeba buetschlii?

8–20 μm Signup and view all the answers

What type of organisms are visible in unstained preparations for most species?

Granules Signup and view all the answers

How are the pseudopods of Entamoeba coli characterized?

Blunt and progressive Signup and view all the answers

Which organism is usually eccentric in its shape?

Entamoeba hartmanni Signup and view all the answers

Which of the following is true about the movement of Dientamoeba fragilis?

It is typically sluggish and associated with one nucleus Signup and view all the answers

Study Notes

Babesia Microti

Babesia microti is a tick-borne parasite that infects red blood cells.
The parasite can cause babesiosis, a disease that can be asymptomatic or cause hemolytic anemia.
Symptoms of babesiosis include fever, chills, headache, fatigue, and muscle aches.
Babesiosis is more severe in people who have a weakened immune system or are splenectomized.
Some patients may harbor the parasite for months and show serologic evidence of infection with no history of clinical disease.
The FDA has approved tests for the detection of Babesia microti in whole blood and plasma.

Leishmania

Leishmania is a genus of protozoan parasites that cause leishmaniasis, a disease that affects the skin, mucous membranes, and internal organs.
Leishmania parasites are transmitted to humans through the bite of infected sandflies.
Leishmania species include L. mexicana, L. amazonensis, L. aethiopica, L. peruviana, and L. guyanensis.
L. mexicana often causes Chiclero ulcers, which are self-limiting lesions that involve the earlobe.
L. mexicana and L. amazonensis can produce diffuse cutaneous lesions, which are similar to those produced by L. aethiopica.
L. peruviana causes uta, a benign cutaneous lesion that occurs predominantly in children.
Leishmania spp have a kinetoplast and do not stain with Gomori methenamine silver (GMS) or periodic acid–Schiff (PAS), while Histoplasma lack the kinetoplast and stain with PAS and GMS.

Intestinal and Urogenital Protozoa

Protozoa inhabiting the human intestinal tract include amebae, flagellates, ciliates, and coccidia.
Intestinal protozoa may be nonpathogenic.
Microsporidia also inhabit the human intestinal tract.
The morphology of amebae can vary, with different species having different sizes, shapes, and motility.
The presence of amebae in stool samples can indicate infection.

Entamoeba Histolytica/Dispar

Entamoeba histolytica and Entamoeba dispar are amebae that infect the intestines of humans.
They are differentiated from other amebae by their size, shape, and motility.
Entamoeba histolytica is considered pathogenic and can cause amebic dysentery.
Entamoeba dispar, in contrast, is generally considered nonpathogenic.

Dientamoeba Fragilis

Dientamoeba fragilis is an ameboid-appearing protozoan that infects the colon, and has been associated with diarrheal disease, especially in young children.
It is morphologically similar to amebae but is a flagellate with two nuclei.
Dientamoeba fragilis is often associated with diarrhea, abdominal pain, and bloating.

Amebic Cysts

Amebic cysts are a stage in the life cycle of amebae.
Cysts are resistant to environmental conditions and can survive outside of the host for long periods.
The morphology of amebic cysts can vary depending on the species.
Entamoeba Histolytica/Dispar cysts are spherical and range in size between 10 and 20 µm. They contain four nuclei and are usually found in the stool of infected individuals.
Entamoeba Coli cysts are generally spherical and range in size from 10 to 25 µm. They have a more granular appearance than E. histolytica cysts.
Endolimax Nana cysts are typically spherical and measure 8–12 µm in diameter. They contain a single nucleus and a large central karyosome.
Iodamoeba Buetschlii cysts have a characteristic appearance with a single large nucleus containing a prominent karyosome and irregular chromatin. They are typically 8–20 µm in size.
Dientamoeba Fragilis does not have a cystic stage.

Treatment

Metronidazole is the drug of choice for treatment of Entamoeba histolytica infection.
Tinidazole and iodoquinol are alternative drugs for treatment.
Treatment for other intestinal protozoal infections depends on the specific species involved.

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Description

Explore the characteristics of Babesia microti and Leishmania, two important parasites impacting human health. Learn about their transmission, symptoms, and the diseases they cause, including babesiosis and leishmaniasis. This quiz covers vital details about detection methods and affected populations.