Specimen source

Microscopic examination of peripheral blood may be diagnostic for infection with each of the following parasites EXCEPT:

Trichinella spiralis

All of the following represents organisms with the appropriate specimen type for diagnosis EXCEPT:

Trichomonas tenax- vaginal secretions

All of the following characteristics should be observed for and noted in the macroscopic examination of a stool sample for parasites EXCEPT?

Time that last meal occurred

The image shows an iodine stained cyst, measuring 20 µm in diameter, most commonly observed in a stool specimen obtained from a patient with persistent or intermittent diarrhea with or without fever. The nucleus is characterized by a centrally located karyosome. Which of the following organism is depicted in the image?

Entamoeba histolytica

This suspicious form, found in a stool sample, measures 15 µm. What is it?

Entamoeba histolytica

The skin infection of the foot of a farmer as illustrated in the upper photograph was caused in a farmer when walking barefoot in soil contaminated with a filariform larva. Based on the morphology of the 50 µm in diameter ovum (lower image), select from the question/answer list the species that is the presumptive cause of this infection

Necator americanus

This intestinal parasite, which measures 5 µm, is usually not visible in samples processed using standard permanent stains. Special staining, as indicated by the coloring here, is helpful in its identification.

Cryptosporidium oocyst

The story might be told that a pathologist, when first viewing an H & E - stained section of an endoscopic biopsy of duodenum (upper left image), may seek a consultation. The specimen was obtained from a patient with a mal-absorption syndrome. After observing tiny acid-fast globules along the intestinal epithelial lining cell (arrows, upper right image), one of the laboratory microbiologists was consulted for an answer. Having a presumptive identification in mind (lower left image), the microbiologist prepared an acid-fast stained smear of intestinal fluid (lower right image) and observed tiny 5 µm in diameter oocysts. From the multiple choices listed, select the presumptive identification, select what parasite the microbiologist might have reported.

Cryptosporidium parvum

The photomicrograph is of a histological section of duodenum in which are observed small, 5 µm in diameter spores that adhere to the surface epithelium. Although a presumptive identification can be made by demonstrating acid fast staining of these spores, monoclonal antibody-based DFA assays of stool specimens provide a more sensitive final identification. Select from the multiple choices the probable identification.

Cryptosporidium species

Which of the following amoeba cyst measures around 25 µm?

Entamoeba coli

The image to the right displays a protozoa measuring 25 µm that was found in stool. Which of the following does this image represent?

Entamoeba coli trophozoite

The object shown in the image at the arrow was found in a formed stool and measured 15 mm with 4 nuclei, small compact karyosomes, and fine, uniform peripheral chromatin.

Entamoeba histolytica cyst

Illustrated in the image shown is a 20 µm amoebic trophozoite that was observed in a random stool specimen from a patient who had no symptoms of a parasitic infection. Several molecular based studies have found that in the analysis of stable DNA polymorphisms, several differences in DNA zymodeme patterns were found to encode for genetically different strains of Entamoeba histolytica. As some of these strains were found to be non-pathogenic, it has been recommended that the laboratory report be altered to draw attention to this possibility. Select from the choices below the report that should be issued.

Entamoeba histolytica/dispar

This suspicious form, seen in a cellophane tape preparation, measures 54 µm by 28 µm.

Enterobius vermicularis egg

The illustration demonstrates a non-pathogenic amoeba described as being 5-20 µm, containing a large glycogen mass, and a single nucleus with a large karyosome and no peripheral chromatin:

Iodamoeba b?tschlii cyst

A 44-year-old female immigrant from Southeast Asia presented to the local clinic complaining of fever, chills, diarrhea and weakness. Patient history revealed that the woman worked in a research laboratory in her homeland. Her primary project was to develop an effective insecticide for the dreaded sandfly. The doctor decided to culture her blood for parasites. This form, measuring 14 µm, was recovered. The patient is most likely suffering from:

Kala-azar

In the image, what morphologic structure is shown in section D on this parasite form?

Karyosome

A 58-year-old male, who recently returned from an extensive overseas business trip to Africa, presented to the local clinic complaining of nausea, vomiting, and an achy feeling all over his body. At first, he thought it was just the flu, but it persisted. The doctor ordered a battery of tests including blood smears for parasitic study. This suspicious form was recovered. The patient is most likely suffering from

Malaria

In the image to the right, identify the nuclear structure at the arrow of letter C.

Micronucleus

Illustrated in the photomicrograph is a high-power view of the elements within a duodenal aspirate preparation using a Weber Stain (Chromotope 2R, Fast Green, phosphotungstic acid). This stain is used to identify the tiny 1.5 µm pink-red staining spores, many with central transverse septa as:

Microsporidium species

Illustrated in this photomicrograph is a silver-stained section of duodenal epithelial cells invaded by 1.5 µm in diameter spores (arrows). They appear red in the Weber-stained mounts (image not shown here). The presumptive identification is:

Microsporidium species

Illustrated in the upper photograph is a 15-year-old native of Guatemala who presents with a 20 mm elevated skin nodule of the right forehead. A Giemsa-stained mount of aspirated fluid from within the nodule is shown in the lower image. From the appearance of the skin lesion and the microfilaria seen in the microscopic mount, select from the multiple choices the presumptive clinical and laboratory diagnosis.

Onchocerca volvulus

A 38-year-old male presented to the E.R. complaining of severe cough, chest pain, shortness of breath, and general fatigue. Parasitic examination of his bloody sputum revealed this suspicious form. The patient is most likely suffering from:

Paragonimus westermani

The adult fluke related to the 100 µm ovum, as illustrated in the image shown, most commonly inhabits the lung parenchyma. The ovum, as may be observed in a sputum specimen, has a smooth, slightly thickened shell with a prominent shouldered operculum as seen at the left lower end. A developing larva is observed within, retracting from the inner margin of the shell leaving a clear space. Infections with this fluke are endemic in the orient, in West Africa, in South and Central America and may be observed in patients elsewhere after travel to one of these regions. Humans become infected after ingestion of poorly cooked crab meat or crayfish contaminated with metacercariae. Intermittent chest pain, and cough with occasional spitting up of blood (hemoptysis) may be experienced after infection. From the choices below, select the trematode species related to this ovum.

Paragonimus westermani

Babesia is a parasitic organism that morphologically resembles which of the following?

Plasmodium falciparum rings

All of the organisms are listed with a common site of recovery for that parasite, EXCEPT:

Plasmodium falciperum - ocular secretions

Illustrated in the image of a Wright-stained peripheral blood smear is a developing intra-erythrocyte schizont. In review of this presentation, select from the multiple choices listed below the Plasmodium species represented by the image as shown.

Plasmodium vivax

Which of the following is the correct order when performing a permanent stained smear of a stool specimen?

70% ethanol/D'Antoni's iodine; 70% ethanol; Trichrome stain; 90% ethanol;100% ethanol; Xylene

Which of the following parasites has a life cycle that most closely resembles that of Plasmodium species?

Babesia microti

The trophozoite illustrated in the photograph is large, measuring 120 µm, representative of what might be observed in a stool specimen obtained from an immune-compromised patient with low-grade diarrhea. Select from the multiple choice responses to derive a presumptive identification.

Balantidium coli

Which of the following substances, when present in a sample, may mask parasites?

Barium

The egg in the picture is found in a stool sample. It has a lateral spine and measures 75 µm by 55 µm. Which intestinal helminth egg is it?

Schistosoma japonicum egg

These suspicious forms were recovered in cerebrospinal fluid (CSF). They are responsible for causing:

Granulomatous amebic encephalitis

How long after hospitalization would stool samples be rejected for testing for parasitic infections?

Greater than 72 hours

A single adult worm that contains both male and female sex organs is known as:

Hermaphroditic

All of the following are included in a standard ova and parasites examination, EXCEPT:

A parasite culture

The parasitic form shown in the illustration may be found in the eye, as a cause of keratitis. It measures approximately 25 µm in diameter. What is the identity of this parasite?

Acanthamoeba species

Illustrated in the upper image is a stained histological section of a bowel showing a heavy inflammatory reaction within which 10 - 12 µm spherical cysts are observed. The lower image is a close up view of one of the trophozoites from a smear preparation of the exudates. There is a distinctive central karyosome, even distribution of the ring of chromatin, and the finely granular cytoplasm. What disease can be presumptively reported?

Amebiasis

Identify the species associated with the parasitic forms found in a stool specimen, as illustrated:

Ancylostoma duodenale

Based on the following choices, which one is the best way to identify microfilariae?

Arrangement of nuclei; presence or absence of a sheath

An 18 year old female athlete, who recently competed in a barefoot run for charity in Southern Georgia, presented to her doctor for a routine check-up. Other than complaining of being exhausted and having occasional diarrhea, she was in good health. The doctor ordered a stool for culture and parasite examination. The culture was negative. Numerous suspicious forms as shown in the attached image were seen upon microscopic examination of the stool. The most likely identification is:

Artifact

Identify the suspicious form (shown in the image) found in a stool specimen, measuring 50 µm.

Ascaris lumbricoides egg

The image to the right represents an egg that was found in stool and measures 55 µm. Which of the following parasitic eggs does this image represent?

Ascaris lumbricoides egg

What is the optimal specimen type to diagnose a Naegleria fowleri infection?

Cerebrospinal fluid(CSF) sample

Illustrated in the photomicrograph is a relatively small pear-shaped trematode ovum, averaging 25 - 35 µm, as might be microscopically observed in a stool sample preparation. The shell is smooth and slightly thickened. Distinctive is the shouldered operculum at the cephalic end of the shell and a small knob at the posterior margin (arrows). Developing larvae at varying stages are observed internally. The adult flukes are most commonly found within the liver bile duct system and may cause obstruction and intermittent jaundice. What is the best presumptive identification?

Clonorchis sinensis

Which cyst is identified in Section D of the image shown?

Endolimax nana

This suspicious form, found in stool, measures 10 µm. What is the identification?

Endolimax nana trophozoite

A 21-year-old male presented in the emergency room with symptoms resembling a liver infection. The patient complained of abdominal pain, fever, cough, nausea, vomiting and constipation alternating with diarrhea. Further examination revealed the presence of a hepatic abscess. The form in the attached image was recovered following parasitic examination of a sample from the abscess and measures 20 µm. What condition is the patient most likely suffering from?

Extraintestinal amebiasis

Illustrated in the close-in high power microscopic view is a large spherical ovum measuring 130 µm as it may appear in a mount of fecal material. These ova often have a brown staining that suggests passage through a biliary duct on its way through the large intestine. Identifying characteristics include a thin, smooth shell and an indistinct, flat, non-shouldered operculum (blue lines). Based on the appearance of this ovum, select from the multiple choices the correct presumptive identification.

Fasciola hepatica

This suspicious form, found in stool, measures 54 µm by 32 µm. What is the identification?

Hymenolepis egg

Which of the following can be found in cerebral spinal fluid (CSF) and measures approximately 15 µm?

Naegleria fowleri trophozoite

The ideal stool sample for parasitic examination is one that is freshly collected and submitted to the laboratory at:

Room temperature (approximately 22° C)

Schistosoma species can be differentiated by the shape and location of a spine located on the egg. Of the following, which species is paired with the correct location of the spine for that species?

S. mansoni - Large lateral spine

A 16-year-old male champion athlete went to his doctor complaining of a persistent cough, fever, bloody diarrhea and overall weakness. Upon questioning the patient, it was learned that he had recently competed in a freshwater swimming competition in the Caribbean. Examination revealed a dermatitis on the patient's right calf. A battery of tests were ordered including a CBC, chemistry profile, and a stool for culture and parasitic examination. The CBC revealed the presence of eosinophilia. The other hematology and chemistry tests were unremarkable. The culture was negative. A suspicious egg form was seen on all parasite preparations made from the stool sample submitted. This form measured 165 µm by 68 µm and had a large lateral spine. (See image to the right) This patient is most likely suffering from an infection with:

Schistosoma mansoni

The image on the right depicts a suspicious form recovered in stool. This form measures 120 µm by 63 µm, what is the most likely identification?

Schistosoma mansoni

The Entamoeba histolytica trophozoite is usually characterized by the presence of the following:

Small central karyosome in the nucleus, ingested RBCs

A fresh stool sample was submitted to the laboratory for an ova and parasites examination on a 30-year-old male who presented to a local clinic complaining of gastrointestinal discomfort and overall weakness. The sample was immediately processed and this suspicious form was seen. No other suspicious forms were observed. What is the most likely identification of this parasite?

Strongyloides stercoralis

In cases of suspected intestinal parasitic disease, select the name of the parasite, as illustrated by the 50 µm ovum in this image, that may be detected in upper respiratory secretions when stool specimen preparations are negative.

Strongyloides stercoralis

A cyst was found in a human brain biopsy with characteristics of a cysticercus. These cysts may develop also in other body sites, particularly in the lungs. Cysticercosis in humans most commonly occurs as part of the life cycle of a tapeworm, the species of which is indicated by the proglottid shown in this image. From these observations, what is the name of the tapeworm of which cysticercosis is part of its life cycle?

Taenia solium

At an outpatient clinic, a patient comes in with an order for stool ova and parasites (O & P). How should this specimen be collected and transported for best test results?

The specimen should be immediately placed in recipients containing polyvinyl alcohol (PVA) or formalin and transported to the laboratory.

Although not endemic in the United States, travelers and hunters in regions of East and Central Africa may acquire this blood infection from the bite of a tsetse fly. Intermittent fever, headache, joint and muscle pains may be experienced. In chronic cases, central nervous system symptoms such as mental retardation, tremors, and slow gait may lead to somnolence and "sleeping sickness." The invasive curved trypanosomes, as shown in the image of a Wright-stained peripheral blood smear, average 20 µm in length. What is the presumptive species identification of the hemo-flagellate related to this infection?

Trypanosoma rhodesiense

An 18 year old immigrant from the Philippines presented to the local clinic shortly after relocating to the United States complaining of fever and chills. Examination of the young adult revealed enlarged lymph nodes. Blood was drawn and submitted for culture and parasitic examination. The culture was negative. This suspicious form was seen on the Giemsa-stained blood smear. It measures 225 µm in length. This patient is most likely infected with:

Wuchereria bancrofti

A 12-year-old female went to her doctor for her yearly back-to-school check-up. She was in good health and was asymptomatic at the time of the examination. Due to the increased incidence of parasites in the area, the doctor ordered a stool for parasite examination as part of the routine physical testing. Multiple suspicious forms, measuring approximately 9 µm each were seen. Which of the following is most likely the identification of these forms?

Endolimax nana

The 20 µm in diameter cyst illustrated in the photograph had been observed microscopically in a trichrome stained mount prepared from a stool specimen of a patient with low grade, intermittent diarrhea. What is the presumptive identification?

Entamoeba coli

What organism (represented in the photomicrograph--showing a pear-shaped organism with a spiral groove across the ventral surface) is recovered from a stool sample and measures 15 µm by 8 µm?

Enteromonas hominis trophozoite

A 7-year-old male presented to the local clinic experiencing mild, yet annoying, abdominal pain, diarrhea and nausea. Patient history revealed that the child lives in a shack where sanitation practices are marginal, at best. The dwelling is infested with rats and multiple insects. Stool was collected and submitted for an ova and parasites examination. Numerous suspicious forms, as depicted in the image to the right, measuring 60 µm by 75 µm were seen. This child is MOST likely infected with:

Hymenolepis diminuta

Recovered from a sputum sample, this suspicious form measures 112 µm by 55 µm. What is the organism?

Paragonimus westermani egg

Upon reviewing a fecal preparation for Ova and Parasites, a technologist thought they had just identified the egg of Taenia saginata. After a quick look, the microbiology supervisor reminded the technologist that T. saginata eggs are indistinguishable from which of the following?

Taenia solium

Identify the form found in stool (illustrated here), measuring 33 µm in diameter.

Taenia species egg

The 40 µm in diameter ovum illustrated in the photograph may be observed in the stool specimens of individuals presenting with minimal abdominal discomfort and low grade diarrhea. Pairs of hooklets are observed internally in the absence of an internal membrane. Select from the multiple choice answers the presumptive identification of this cestode ovum.

Taenia spp.

A 35-year-old male presented to the local clinic complaining of abdominal cramps, severe diarrhea, and intestinal gas. A stool specimen was collected for parasite examination. It was foul-smelling and light colored in nature. The form in the attached image was recovered and measured 10 µm by 12 µm. The patient is infected with which of the following?

Giardia duodenalis (formerly lamblia)

The photograph demonstrates a microorganism detected in a stool sample submitted for ova and parasite examination. The organism measures 12 µm by 7 µm.

Giardia duodenalis cyst

Identify the parasite seen in the image that is sometimes found in stool as well as in duodenal contents. The organism in the image measures 15 µm in length

Giardia duodenalis trophozoite

Whipworm infection may be diagnosed in stool specimens by microscopic observation of adult worms or barrel-shaped eggs with polar plugs. Which species is known as the whipworm?

Trichuris trichiura

A blood specimen collected in EDTA was submitted to the laboratory from a patient that recently returned from a missionary trip to West Africa. The patient presented with fever and lymphadenopathy. The physician requested that the laboratory examine a blood smear for parasitic infection. The image shows the parasite in the specimen. Identify this parasite.

Trypanosoma brucei

Illustrated in the photomicrograph are acid-fast stained mounts of a 5 µm oocyst of Cryptosporidium (top) and a 10 µm oocyst of Cyclospora (bottom). Knowing the clinical suspicion of what disease would alert the laboratory scientist that a preparation of an acid fast stain should be made on the submitted stool specimens?

AIDS

Illustrated in the upper photograph is an adult trematode fluke that in human infections is most commonly found in the distant bile ducts of the liver. The fluke is relatively small, averaging 12 - 20 mm. The lower image is a close in view of this fluke to better illustrate its internal structures. Symptoms during infection may be minimal, but liver enlargement and jaundice may be experienced in heavy infections. Human infections are endemic in southern China. What is considered the appropriate identification?

Clonorchis sinensis

The patient was a 55-year-old male immigrant from Korea. His current symptom was severe jaundice. He had had intermittent less severe bouts of jaundice in the past. During surgery, his proximal bile duct appeared to be enlarged with a nodular area of inflammation. A surgical biopsy was done and a parasite was observed in a stained tissue section residing in the lumen. Further examination revealed a collection of ova within the ovary of this fluke as see in this image (arrow). Which of the organisms listed below is most likely?

Clonorchis sinensis

In hookworm cases where progressive anemia is present, what additional test procedure should be performed to determine infection in stool specimens?

Concentration technique

A 27-year-old missionary returned from a three week visit to Panama. He presented to the emergency department with severe watery diarrhea, weight loss, abdominal pain, nausea and vomiting, a low grade fever, and fatigue. Fresh stool specimens were collected and submitted for ova and parasite examination. The images show a wet mount preparation of a cyst seen in the stool and a dry slide of the same cyst stained by modified acid-fast. Cysts are spherical and measure 8µm in diameter. What is the most likely identification of this parasite? Images courtesy of CDC DPDx.

Cyclospora cayetanensis

Which of the following is the rigid, nonmotile diagnostic stage of the amebae which is generally found in the formed stool?

Cyst

The organism in the attached drawing measuring 20 µm x 15 µm was found in stool. What is it?

Cystoisospora belli (formerly Isospora belli) oocyst

Illustrated in the image shown is a small (10 µm) ameboid-like oval trophozoite with a pair of nuclei, each with prominent karyosome that is often fragmented. This trophozoite was observed in a stool specimen of a person with intermittent persistent diarrhea and fatigue. What is the best presumptive identification?

Dientamoeba fragilis

Illustrated in the photomicrograph is a small 8 µm ameboid-like oval trophozoite with a pair of nuclei each with prominent karyosomes. This trophozoite was observed in a stool specimen of a person with intermittent persistent diarrhea, loss of appetite and flatulence. What is the presumptive identification of this organism?

Dientamoeba fragilis

This parasite measures 12 µm and is found in the stool. It may easily be mistaken for fecal debris, and reported incorrectly as a a nonpathogenic fecal contaminant.

Dientamoeba fragilis trophozoite

A 54-year-old Finnish male presented at the local clinic with abdominal pain, weight loss, overall weakness and digestive discomfort. Patient history revealed that the man's diet was rich in raw fish. A complete blood count (CBC) was performed and revealed macrocytic anemia. A stool for parasitic examination was ordered. This suspicious form was seen upon initial screening of the sample. It measures 70 µm by 48 µm. This patient is most likely suffering from an infection with:

Diphyllobothrium latum

Stool is the specimen of choice for the recovery of which of the following parasites?

Diphyllobothrium latum

Illustrated in the upper photograph image is an open segment of a surgically removed segment of small intestine on the surface of which are adult Cestode worms. The lower image is a view of a stained proglottid obtained from one of the adult worms. Based on the morphology of the proglottid, select the presumptive identification of the adult worms observed in this intestinal segment.

Dipylidium caninum

A stool was received in the laboratory for parasitic examination on a 49-year-old female who just returned from missionary work in numerous developing countries around the world. The patient had been suffering from mild diarrhea over the previous two weeks. This suspicious form was seen. Notice in the image, five nuclei are visible. Upon focusing between two focal planes, a total of eight nuclei were observed. It measures 25 µm. What is the identification of this form?

Entamoeba coli

This parasite resides in the mouth where, when present, measures approximately 17 µm.

Entamoeba gingivalis trophozoite

This suspicious form, which measures 20 µm, was recovered in sigmoidoscopic material. Name that parasite!

Entamoeba histolytica

A situation may arise when a pathologist recognizes the presence of a parasite in an H & E - stained section within the lumen of the appendix, as seen in the upper Image. Studies of additional fields of view in the slide may locate the ovary and reveal the morphology of the ova contained within, as is observed in the lower image. Based on these observations, select the presumptive identification of this parasite.

Enterobius vermicularis

The 20 mm mature adult fluke illustrated in the photograph has a normal habitat in the liver bile ducts. Humans become infected by ingesting raw or undercooked water plants contaminated with infective metacercaria. These adult flukes are only observed during surgery involving the liver or at autopsy. Intermittent upper abdominal discomfort and low grade jaundice may be experienced. From the multiple choices listed, select the presumptive identification of this fluke.

Fasciola hepatica

A 55-year-old female, who recently returned from an extensive trip to China, presented to her physician complaining of diarrhea and abdominal cramps. The doctor ordered a complete blood count (CBC), comprehensive metabolic panel (CMP), and stool for culture and parasite examination (O & P). The CBC revealed pronounced eosinophilia. The CMP and stool culture were unremarkable. The O & P revealed suspicious forms like the one below that each measured approximately 140 µm by 80 µm. This patient is most likely infected with:

Fasciola/Fasciolopsis eggs

This parasite may inhabit the small intestine or take up residence in the bile ducts. Its egg typically measures 145 µm by 75 µm.

Fasciolopsis/Fasciola species egg

A 40-year-old male just returned from a six-month tour of the Far East. He went to his doctor upon his return complaining of weakness, diarrhea, fever and cough. Upon questioning the patient it was learned that he spent many an evening swimming in the various local fresh water ponds. The doctor, suspicious of a parasitic infection, ordered a stool for examination. Two suspicious forms were seen: form 1 is roundish and measures 77 µm by 62 µm. Form 2 is long and ladder-like and lays on the edge of form 1. What are these two structures?

Form 1 - cyst; Form 2 - artifact

A large number of antigen detection procedures and assays are available to diagnose clinically suspected parasitic diseases in the absence of finding ova or other forms of parasites in stool preparations or other body fluids. Illustrated in the photograph are antigen positive-staining green dots at sites where small drops of duodenal aspirated fluid had been applied to the test reagents. Trophozoites of this protozoan occupy the upper gastrointestinal tract and the excreted ova may not find the way down the long stretch of bowel to be excreted in stool specimens. From the list of multiple choice selections, indicate the genus/species in which antigen detection may be required to make a diagnosis.

Giardia duodenalis

Illustrated in the photograph is a 15 X 25 µm trophozoite recovered from the stool specimen of a 30-year-old man with intermittent chronic diarrhea and malabsorption with onset 4 months after a camping trip to the nearby mountains. From the multiple choices listed, select the most probable presumptive identification.

Giardia duodenalis

When parasites are observed in clinical stool specimens, antigen detection is the preferred method for identification, providing increased sensitivity over more common microscopy techniques. Several commercial products (DFA, EIAs, and rapid tests) are available. The H & E - stained tissue section of duodenum illustrates the presence of an intra-luminal intestinal trophozoite in which an antigen assay might be helpful in making a definitive identification. Select the presumptive identification from the choices listed.

Giardia duodenalis

The 70 µm ovum illustrated in the high power microscopic view of a saline preparation is uncommonly found in human feces. The cestode represented by this ovum is more commonly found in rats and mice, but infections may be uncommonly transmitted to humans. Water or food contaminated with arthropod related insects within which the cysticercoid larval forms develop may be inadvertently ingested. Once in the human intestine, these larvae develop into adults that attach to the lining cells, and excrete ova that may be observed in fecal specimens. From the multiple choices listed below, select the name of the cestode represented by this ovum.

Hymenolepis diminuta

This image is of a 45 µm ovum that may be observed in stool specimen preparations. In patients with HIV immune-suppression, many ova may be seen in stool specimens in cases of heavy infection. Abdominal pain, bloating, diarrhea, and possible bowel obstruction may be presenting symptoms. Select the presumptive identification of this tapeworm ovum from the multiple choice answers listed below.

Hymenolepis nana

This suspicious form measures 18 µm and was seen in ova and parasite exam from a stool specimen. The most likely identification is:

Iodamoeba b?tschlii

A 27-year-old male submitted a stool for culture and parasite study. The culture revealed no enteric pathogens. The suspicious form in the photograph was seen on the permanent trichrome stain. It measured 10 µm. Which of the following is the most likely identification?

Iodamoeba butschlii

A 40-year-old business man developed intermittent spiking fevers one week following a trip to Western Africa. The Wright-stained peripheral blood smear as illustrated in the image was observed. Based on the morphology of the erythrocytes and the heavy invasion with ring form trophozoites, the diagnosis of malaria could be made. With particular focus on the sickle-form gametocyte, which Plasmodium species is represented by this peripheral blood smear?

Plasmodium falciparum

A 31-year-old female with a known history of amebiasis, presented to her physician complaining of bloody diarrhea and fever. Previous patient history revealed that she lives in substandard conditions. Parasitic examination of the woman's stool revealed this suspicious form that measures 20 µm. The identification of this form is:

Pseudoparasite

A 45-year-old mother of two went to her physician because her children were recently diagnosed with ascariasis and she was concerned that she had also contracted the disease. Other than complaining of recent sporadic diarrhea, she was in overall good health. The doctor ordered a stool for ova & parasite examination. This suspicious form, measuring 55 µm was seen throughout the sample. This form is most likely:

Pseudoparasite

This suspicious form, shown here under both low and high power, was found in a stool sample and measures 50 µm.

Pseudoparasite

The ovum as illustrated in the high-power photomicrograph, averages 140 µm. These ova are most commonly observed in a urine sediment from a patient complaining of frequent urination, dysuria, hematuria and recurrent urinary tract infections. Note the characteristic delicate, sharply pointed terminal spine (blue arrow) extruding from the anterior margin of the shell. From the multiple choices listed below, select the presumptive identification of this ovum.

Schistosoma haematobium

Illustrated in the high power photomicrograph is a large 140 µm ovum as it would appear in a stool specimen preparation. The adult flukes reside in the portal veins of the large intestine where ova are discharged into the lumen and into the feces. Low grade diarrhea may be experienced. From the multiple choices select the species of fluke related to this ovum.

Schistosoma mansoni

A stool specimen has been left at room temperature overnight. The next day, many motile larvae with a short buccal cavity are seen upon microscopic exam, but there are no ova observed. What is the most likely identification and life stage of this parasite?

Strongyloides stercoralis - rhabditiform larvae

The best sample to obtain in order to diagnosis the parasite causing the posterior scalp nodule as illustrated in the photograph is:

Superficial skin snip

Methods of detecting and identifying intestinal parasites include all of the following except:

Thin and think Giemsa smear

Which parasite can be recovered from the eye?

Toxoplasma gondii

A women presents to her physician with complaint of a foul smelling vaginal discharge. The following are reported from the submitted sample of the yellow vaginal secretion: Wet prep: Many WBCs seen, no Clue cells seen, microorganism (20µm) seen with jerky motility Vaginal pH: 6.0 Amine (Whiff) Test: Positive What is the most likely cause of this vaginal infection?

Trichomonas vaginalis

Many organisms depicted as the image labeled 'B' were found in a urine specimen of a 28-year-old male that was tested as part of a routine physical examination. What is the identification of the organisms?

Trichomonas vaginalis

A 31-year-old male missionary worker recently returned from Africa where he helped a small rural community update their sanitation practices. He presented to his physician weak and complained of recent weight loss, abdominal pain, and diarrhea that was often bloody. The doctor ordered a battery of tests including a complete blood count (CBC) and stool for parasite examination. The CBC revealed eosinophilia and anemia. This suspicious form was seen on the wet preparations. It measured 52 µm by 27 µm. What parasite is mostly likely present?

Trichuris trichiura

A 4-year-old female from South Carolina who was suffering from malaise, bloody diarrhea and abdominal pain, was rushed to the emergency room. Examination revealed rectal prolapse. Stool was submitted for parasitic examination and this suspicious form was seen. It measures 45 µm by 20 µm. Which of the following is the correct identity of this suspicious form?

Trichuris trichiura

Illustrated in the upper photograph is a 50 mm long nematode adult worm as primarily found in the cecum in cases of human infection. Rectal prolapse may be a complication if infection is heavy. These adult worms are not observed in stool specimens but more commonly may be seen embedded in the epithelium of a prolapsed rectum. The identification can be made by observing the characteristic ovum in fecal specimens as illustrated in the high-power lower photomicrograph. What would be the presumptive identification?

Trichuris trichiura