Parasitology Key Concepts and Treatments

Questions and Answers

Which of the following are key discoveries that contributed to current knowledge about parasites?

Development of new drug therapies

Improved sanitation practices

Enhanced public awareness campaigns

Modifications of traditional parasite identification techniques (correct)

Which of the following people may be at risk for contracting a parasitic infection?

A toddler who attends an all-day preschool or daycare center (correct)

A 37-year-old South American refugee (correct)

A teenager with proper hygiene

An adult living in a developed country

What is the primary function of a host in a parasite-host relationship?

Carry on the parasite's life cycle.

Which of the following key pieces of information may be extracted from the portion of a parasite's life cycle that occurs outside the body?

Epidemiology Signup and view all the answers

Which of the following groups of systems represents those most commonly observed in parasitic infections?

Gastrointestinal system Signup and view all the answers

Which of the following represents examples of available treatment therapies to combat parasitic infections?

Change in diet Signup and view all the answers

Which of the following are examples of possible parasite prevention and control measures?

Practicing proper sanitation practices Signup and view all the answers

Which specimen type is most often submitted for parasite study?

Stool. Signup and view all the answers

Which of the following correctly represents the three major groups of clinically significant parasites?

Protozoa, Metazoa, Arthropods Signup and view all the answers

How many stool samples should be collected when following the typical O&P collection?

3 Signup and view all the answers

What is the purpose of fixatives for the collection of stool samples?

Preserve the morphology of protozoa and prevent further development of helminths. Signup and view all the answers

Which of the following characteristics is observed during the macroscopic examinations of stool specimens?

All of the above Signup and view all the answers

Which of these procedures is involved in the microscopic examination of stool specimens for parasites?

Performing a concentration technique. Signup and view all the answers

The direct wet preparation can be eliminated from the O&P examination if the specimen is received in a fixative.

True Signup and view all the answers

Which of the following parasitic stages is not usually detected after using a concentration technique?

Protozoan trophozoites Signup and view all the answers

The permanent stained smear is crucial for the detection of helminth eggs and larvae.

False Signup and view all the answers

What is one advantage of the stool screening method?

It is highly sensitive and specific. Signup and view all the answers

From which area can the Enterotest be used to collect specimens?

Duodenum Signup and view all the answers

Thick blood smears for malaria are recommended for species identification.

False Signup and view all the answers

Giemsa is the preferred stain for the detection of blood parasites.

True Signup and view all the answers

Which specimen of choice demonstrates intracellular parasites such as Toxoplasma Gondii and Leshmania spp.?

Tissue Signup and view all the answers

The detection of an antibody to a given parasite in a patient with no previous exposure prior to travel to an endemic area can be considered a positive result.

True Signup and view all the answers

Which one of these parasites should be quantitated in a parasitology report?

Blastocystis hominis. Signup and view all the answers

Amebas transform from trophozoites to cysts on entry into an unsuspecting human.

False Signup and view all the answers

Formed stool specimens are more likely to contain which of the following?

Cysts Signup and view all the answers

Infections with intestinal amebas are prevalent in which of the following?

Underdeveloped countries with poor sanitary conditions Signup and view all the answers

Which of the following structures is typical in trophozoites of E. histolytica?

Single nucleus with a small karyosome. Signup and view all the answers

E. histolytica infection is traditionally diagnosed by finding which of the following?

Trophozoites and or cysts in a suspected stool sample. Signup and view all the answers

The infective stage of E. histolytica is which of the following?

Cyst. Signup and view all the answers

Which of the following factors is not responsible for the asymptomatic carrier state of a patient infected with E. histolytica?

Patient's blood type Signup and view all the answers

Which of the following prevention measures can control the spread of E. histolytica?

Boiling water Signup and view all the answers

Which of the following is true regarding E. hartmanni?

The organism is found worldwide. Signup and view all the answers

A main difference between the trophozoites of E. hartmanni and E. histolytica is which of the following?

Trophozoites of E. hartmanni do not contain ingested red blood cells. Signup and view all the answers

The trophozoites of E. coli have a typical nucleus that consists of what?

A large, often irregularly shaped karyosome that is eccentrically located. Signup and view all the answers

Which of the following is not true about E. coli?

It is considered to be a pathogen. Signup and view all the answers

Which of the following statements is not true about the cysts of E. polecki?

Cysts contain at least four nuclei. Signup and view all the answers

Infection with E. polecki is mainly transmitted to humans via which of the following?

Ingestion of E. polecki cysts. Signup and view all the answers

The appearance of an E. nana karyosome is usually which of the following?

Blot-like. Signup and view all the answers

Which of the following statements is true regarding E. nana?

It is normally asymptomatic. Signup and view all the answers

Iodamoeba butschlii cysts typically lack which feature?

Chromatoid bars. Signup and view all the answers

Transmission of I. butschlii occurs through what?

Ingestion of I. butschlii cysts in contaminated food and drink. Signup and view all the answers

Which of the following is a unique characteristic of E. gingivalis?

Is the only ameba that may ingest white blood cells. Signup and view all the answers

E. gingivalis can be found in which locations?

In the mouth and in the genital tract. Signup and view all the answers

The known morphologic forms of Naegleria fowleri are?

Ameboid trophozoites, flagellate forms, and cysts. Signup and view all the answers

The specimen of choice for the recovery of N. fowleri is which of the following?

Cerebrospinal fluid. Signup and view all the answers

Humans often contract N. fowleri by which of the following?

Swimming in contaminated water. Signup and view all the answers

The ameboid trophozoites of N. fowleri enter the human body through all of the following routes except?

Ingesting contaminated food or drink Signup and view all the answers

Practical measures for the control and prevention of N. fowleri include which of the following?

Providing education and awareness in the medical community. Signup and view all the answers

The term acanthopodia refers to?

Spikelike pseudopods. Signup and view all the answers

The specimen of choice for diagnosing Acanthamoeba species trophozoites and cysts is which of the following?

Cerebrospinal fluid. Signup and view all the answers

Humans may acquire Acanthamoeba species by which of the following?

Aspiration or inhalation of the organisms and direct invasion of the parasites in the eye. Signup and view all the answers

Infections with Acanthamoeba species are encountered primarily in which anatomical parts?

Eye. Signup and view all the answers

To prevent infection with Acanthamoeba species, contact lens wearers should avoid which of the following?

Using homemade nonsterile saline solutions. Signup and view all the answers

All flagellate life cycles possess trophozoite and cyst morphologic forms.

False Signup and view all the answers

This flagellate morphologic structure is often not visible under microscopic examination.

Flagella. Signup and view all the answers

The presence of nonpathogenic flagellates is important because it suggests that?

Contaminated food or drink was consumed by the patient. Signup and view all the answers

The proposed functions of the median bodies seen in Giardia intestinalis are?

Support, energy, metabolism. Signup and view all the answers

Which specimen type and collection regimen would be most appropriate for the diagnosis of G. intestinalis?

Multiple stool samples collected on subsequent days. Signup and view all the answers

G. intestinalis trophozoites attach to the mucosa of the duodenum and feed with the assistance of what morphologic structure?

Sucking disk. Signup and view all the answers

Individuals become infected with G. intestinalis by which of the following?

Ingesting contaminated food or drink. Signup and view all the answers

Individuals at risk for G. intestinalis when camping and hiking are encouraged to take which of these steps to prevent infection?

Use only bottled water for drinking, cooking, and appropriate personal hygiene. Signup and view all the answers

Which of the following are key morphologic characteristics of C. mensnili?

Lemon-shaped and presence of a cystosome. Signup and view all the answers

A liquid stool is the specimen of choice for the recovery of which of these forms of C. mesnili?

Trophozoites only. Signup and view all the answers

A flagellate trophozoite that could be described as 9 to 12 um with one or two nuclei, each with four symmetrically positioned chromatin granules and vacuoles containing bacteria in the cytoplasm, would most likely be which of the following?

Dientamoeba fragilis. Signup and view all the answers

The permanent stain of choice for observing the nuclear features of D. fragilis is which of the following?

Iron hematoxylin. Signup and view all the answers

The specimen of choice for the recovery of T. hominis is which of the following?

Stool. Signup and view all the answers

Trichomonas hominis can be transmitted by which of the following?

Contaminated milk. Signup and view all the answers

When E. hominis cysts contain more than one nuclei, where do they tend to be positioned within the cytoplasm?

At the opposite end of the cell. Signup and view all the answers

Treatment is always indicated for patients when E. hominis is present on parasite examination.

False Signup and view all the answers

The traditional technique and specimen of choice for identifying Retortamonas intestinalis is which of the following?

Permanently stained stool. Signup and view all the answers

Individuals contract T. intestinalis by which of the following?

Ingesting infective cysts in contaminated food or drink. Signup and view all the answers

How far down the body length does the Trichomonas tenax undulating membrane extend?

Three fourths. Signup and view all the answers

The specimen of choice for the recovery of Trichomonas tenax is which of the following?

Mouth scrapings. Signup and view all the answers

This prominent structure found in T. vaginalis trophozoites that often extends beyond the body provides the parasite with support is known as?

Axostyle. Signup and view all the answers

The cyst morphologic form is not known to exist in the cycle of T. vaginalis.

True Signup and view all the answers

T. vaginalis may be recovered in which of the following specimen types?

Urethral discharge Signup and view all the answers

All cases of T. vaginalis infection result in symptomatic vaginitis in women and urethritis in men.

False Signup and view all the answers

This is the only hemoflagellate morphologic form that does not have an external flagellum.

Amastigote. Signup and view all the answers

Hemoflagellates are typically found in stool samples.

False Signup and view all the answers

The symptoms of hemoflagellate infections range from minor, such as irritation at the infection site, to serious.

True Signup and view all the answers

Of the following laboratory diagnostic methods, which is the most commonly used for recovery of members of the L. braziliensis complex?

Identifying amastigotes in infected material Signup and view all the answers

The organism causing chiclero ulcer is most likely found in?

South American rain forest region. Signup and view all the answers

Which of the following is an acceptable treatment for mucocutaneous leishmaniasis caused by L. braziliensis?

Pentavalent antimonial compounds Signup and view all the answers

The common name for the disease caused by L. donovani is?

Visceral leishmaniasis Signup and view all the answers

The vector responsible for the transmission of L. donovani is?

Phlebotomus sand fly Signup and view all the answers

Which of the following items does not describe kala-azar?

Is transmitted by blood transfusion Signup and view all the answers

The specimen of choice for the recovery of L. mexicana complex members is?

Lesion biopsy material. Signup and view all the answers

Which of the following is not a reservoir host for the L. mexicana complex?

Snakes Signup and view all the answers

Which of the following best describes the disease caused by the L. mexicana complex?

Appears around the ears in approximately 40% of patients Signup and view all the answers

All of the following are geographic regions in which the members of the L. tropica complex can be found except?

Brazil Signup and view all the answers

The specimen of choice for the recovery of L. tropica complex members is?

Fluid underneath the ulcer bed. Signup and view all the answers

The most common morphologic forms seen in samples positive for L. tropica complex members is?

Amastigote. Signup and view all the answers

Of the following, which tests are considered diagnostic for Trypanosomiasis?

Increased serum and CSF IgM levels Signup and view all the answers

There are no known animal reservoir hosts for T. b. gambiense.

True Signup and view all the answers

The enlargement of cervical lymph nodes in reference to trypanosomal disease caused by T. b. gambiense is referred to as?

Winterbottom's sign. Signup and view all the answers

The diagnostic stages of T. b. rhodesiense is the?

Trypomastigote. Signup and view all the answers

Which of the following trypanosomal parasites that causes sleeping sickness is the more aggressive form?

Trypanosoma brucei rhodesiense. Signup and view all the answers

The specimen of choice for the detection of T. cruzi is?

Blood. Signup and view all the answers

Which of the following is the vector first identified as responsible for transmitting T. cruzi?

Panstrongylus megistus Signup and view all the answers

Which of the following is not a characteristic finding in Chagas' disease?

Somnolence Signup and view all the answers

Study Notes

Key Discoveries in Parasitology

Modifications of traditional identification techniques have enhanced knowledge about parasites.
Understanding of host-parasite interactions reveals primary functions of hosts in carrying life cycles.

Risk Factors for Infection

High-risk individuals include toddlers in daycare centers and refugees from South America.
Epidemiological data can inform prevention and control measures for parasites.

Symptoms and Treatment of Parasitic Infections

Common symptoms include abdominal cramping, pain, and diarrhea.
Diet modification is a potential treatment therapy for parasitic infections.
Prevention measures involve practicing proper sanitation.

Diagnostic Methods for Parasitology

Stool samples are the most frequently submitted specimens for parasite study.
Three stool samples are typically required for optimal O&P (ova and parasite) collection.
Fixatives preserve protozoa morphology and prevent helminth development.

Microscopic Examination Techniques

Macroscopic examinations focus on stool consistency, color, and presence of adult worms.
Concentration techniques are vital for microscopic examination of stool specimens.

Identification of Major Parasite Groups

Three significant parasites: Protozoa (single-celled), Metazoa (worms), and Anthropods (insects).
Thick blood smears are not ideal for malaria species identification; thin smears are preferred.

Life Cycle and Infectious Stages of Parasites

E. histolytica is identified by trophozoites and cysts in stool samples; its infective stage is cysts.
A symptomatic carrier state for E. histolytica is not influenced by blood type.

Prevention and Control Measures

Boiling water or iodine treatment can control the spread of E. histolytica.
Underdeveloped countries are particularly susceptible to infections from intestinal amebas.

Characteristics of Specific Amoebas

E. gingivalis uniquely ingests white blood cells and can be found in the mouth and genital tract.
Naegleria fowleri enters through contaminated water; cerebrospinal fluid is its specimen of choice.

Acanthamoeba Infections

Acanthamoeba can infect the eye and is associated with contact lens use.
Precautions include avoiding homemade saline solutions.

Flagellate trophozoites lack visible flagella under the microscope.
G. intestinalis is diagnosed through stool samples, emphasizing the importance of hydration while camping.

Hemoflagellate Infections

Hemoflagellates cause serious infections, with symptoms ranging from site irritation to systemic disease.
Diagnostic methods often involve identifying amastigotes in infected material.

Leishmaniasis and Treatment

Leishmaniasis caused by L. braziliensis is endemic to South American rainforests and requires biopsy material for diagnosis.
Treatment for mucocutaneous leishmaniasis can include antibiotics like amoxicillin.

Chagas Disease

T. cruzi is transmitted by the Triatomine bug; blood samples are best for detection.
The disease's vector is Panstrongylus megistus, and characteristic symptoms include Winterbottom's sign for lymph node enlargement.

General Notes on Protozoa

E. coli is typically not considered a pathogen despite its worldwide presence.
Cysts of E. polecki lack chromatoid bars and are transmitted through contaminated food and drink.

Additional Points

Permanent stains help visualize the morphology of D. fragilis and other parasites.
Specimen choice varies, with specific presentations influencing the diagnosis and recovery of various parasites.

These notes encapsulate critical concepts and facts from the study material on parasitology, summarizing key elements for effective learning and memorization.

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Description

This quiz covers fundamental topics in parasitology, including identification techniques, risk factors for infection, symptoms, and treatment options for parasitic infections. Additionally, it highlights diagnostic methods essential for studying parasites and their interactions with hosts.