Biology Question 4
Task 1.
During a routine medical checkup of food industry workers there were found cysts
in the feces of one of them. The cysts were round, 12 mcm in diameter, and had a
one-layered coat and four large vesicle-like nuclei. The worker had not complained
of any health problems before the checkup.
1. Write the English and Latin species name of the parasite the cysts of which
were found.
2. Specify the taxonomic status of this parasite (phylum, class, English and
Latin names).
3. Is the worker sick? If so, what is the name of the disease?
4. Should this worker be taken to hospital considering that he has no
symptoms?
5. Which health changes will this worker develop if he is not treated?
Ans. 1. Dysentery amoeba - Entamoeba histolytica. This is confirmed by the shape,
size and presence of 4 nuclei in the mature cyst.
2. Phylum Sarcomastigophora, class Sarcodina.
3. No, the worker is not sick with amoebiasis, as there are no symptoms of the
disease. He is a cyst carrier.
4. No, hospitalization is not required; outpatient treatment with suspension from
work for this period is enough, suspension from work is required because the worker
releases cysts into the external environment and cysts are the infective stage for
humans.
,5. In the absence of treatment, when conditions worsen small vegetative forms turn
into large vegetative (pathogenic) ones, penetrate the mucosa of the intestinal wall
and cause ulceration, patients develop bloody diarrhea, i.e. an acute form of
amoebiasis develops. As they penetrate deeper they turn into tissue forms that can
enter the blood and spread throughout the body causing abscesses (purulent
inflammations) in the liver, lungs and other organs.
Task 2.
A student was admitted to hospital, he had returned from Equatorial Africa six
months before. The examination showed: his lymph nodes were swollen, he had
fever, his nervous system was affected which caused sleepiness especially in the
morning and sleeplessness at night, apathy and headaches. His blood sample and
lymph-node puncture were taken to make a diagnosis. After the samples were
treated with Giemsa stain there were detected parasites in the blood plasma and
puncture sample. These parasites had an elongated body and the undulating
membrane along the body.
1. Which disease does this patient have? Write the English and the full Latin
name of this parasitic species.
2. Which living form (stage) of these parasites was detected in the samples?
Describe its morphological features.
3. Specify the transmission route and mechanism of infection of this disease.
4. Is the sick student a direct source of infection for others? Explain your
answer.
5. Can this disease be classified as a natural focus disease? Explain your
answer.
Ans. 1.The disease is African Trypanosomiasis, also known as
Sleeping Sickness. The parasitic species responsible is
,Trypanosoma brucei, with two subspecies: Trypanosoma brucei
rhodesiense and Trypanosoma brucei gambiense.
2. The stage detected in the samples is the trypomastigote form.
Its morphological features include an elongated body and an
undulating membrane along the body, visible in blood plasma and
lymph-node puncture samples.
3.The transmission route is through the bite of an infected tsetse fly
(Glossina species). The mechanism involves the tsetse fly ingesting
trypanosomes from an infected host’s blood, followed by
development in the fly’s midgut and migration to the salivary glands,
where they can be transmitted to a new host during a subsequent
bite.
4.The sick student is not a direct source of infection for others
because African Trypanosomiasis requires a tsetse fly vector for
transmission. Direct transmission from person to person does not
occur without the vector.
5.Yes, this disease can be classified as a natural focus disease. It
is maintained in nature through a cycle involving the tsetse fly
vector and, for T. b. rhodesiense, animal reservoirs. Human infection
occurs incidentally when individuals enter the natural focus area and
are bitten by an infected tsetse fly. Both subspecies fit the definition
of a vector-borne disease with natural foci.
, Task 3.
A patient came to a urologist, he complained of an excessive discharge from the
urethra, as well as burning sensation, itchiness and pain during urination. The
microscopy of the discharge sample showed unicellular pear-shaped organisms,
25mcm in size, which had four free flagella of the same length. The axostyle was
visible at the posterior end of the body as a spine.
1. Which parasite was detected? Write the English and the full Latin name of
this parasitic species.
2. What was the transmission route?
3. Can the patient be the source of infection for the people around him? Explain
your answer.
4. Which morphological features of this parasite help to distinguish it from the
other species of the same genus?
5. Describe this organism according to the classifications of parasites.
Ans. 1. Vaginal trichomonas – Trichomonas vaginalis.
2. The infection occurred through contact, the mechanism is sexual
contact.
3. The patient is a direct source of infection for his sexual partners
since the infective stage of the parasite is the trophozoite which is
transmitted sexually.
4. The parasite cell is oval or spindle-shaped unlike intestinal and
oral trichomonas’ cell, it is 10-30 mcm in length. The nucleus Is
oval, with slightly pointed ends, located at the anterior widened end
Task 1.
During a routine medical checkup of food industry workers there were found cysts
in the feces of one of them. The cysts were round, 12 mcm in diameter, and had a
one-layered coat and four large vesicle-like nuclei. The worker had not complained
of any health problems before the checkup.
1. Write the English and Latin species name of the parasite the cysts of which
were found.
2. Specify the taxonomic status of this parasite (phylum, class, English and
Latin names).
3. Is the worker sick? If so, what is the name of the disease?
4. Should this worker be taken to hospital considering that he has no
symptoms?
5. Which health changes will this worker develop if he is not treated?
Ans. 1. Dysentery amoeba - Entamoeba histolytica. This is confirmed by the shape,
size and presence of 4 nuclei in the mature cyst.
2. Phylum Sarcomastigophora, class Sarcodina.
3. No, the worker is not sick with amoebiasis, as there are no symptoms of the
disease. He is a cyst carrier.
4. No, hospitalization is not required; outpatient treatment with suspension from
work for this period is enough, suspension from work is required because the worker
releases cysts into the external environment and cysts are the infective stage for
humans.
,5. In the absence of treatment, when conditions worsen small vegetative forms turn
into large vegetative (pathogenic) ones, penetrate the mucosa of the intestinal wall
and cause ulceration, patients develop bloody diarrhea, i.e. an acute form of
amoebiasis develops. As they penetrate deeper they turn into tissue forms that can
enter the blood and spread throughout the body causing abscesses (purulent
inflammations) in the liver, lungs and other organs.
Task 2.
A student was admitted to hospital, he had returned from Equatorial Africa six
months before. The examination showed: his lymph nodes were swollen, he had
fever, his nervous system was affected which caused sleepiness especially in the
morning and sleeplessness at night, apathy and headaches. His blood sample and
lymph-node puncture were taken to make a diagnosis. After the samples were
treated with Giemsa stain there were detected parasites in the blood plasma and
puncture sample. These parasites had an elongated body and the undulating
membrane along the body.
1. Which disease does this patient have? Write the English and the full Latin
name of this parasitic species.
2. Which living form (stage) of these parasites was detected in the samples?
Describe its morphological features.
3. Specify the transmission route and mechanism of infection of this disease.
4. Is the sick student a direct source of infection for others? Explain your
answer.
5. Can this disease be classified as a natural focus disease? Explain your
answer.
Ans. 1.The disease is African Trypanosomiasis, also known as
Sleeping Sickness. The parasitic species responsible is
,Trypanosoma brucei, with two subspecies: Trypanosoma brucei
rhodesiense and Trypanosoma brucei gambiense.
2. The stage detected in the samples is the trypomastigote form.
Its morphological features include an elongated body and an
undulating membrane along the body, visible in blood plasma and
lymph-node puncture samples.
3.The transmission route is through the bite of an infected tsetse fly
(Glossina species). The mechanism involves the tsetse fly ingesting
trypanosomes from an infected host’s blood, followed by
development in the fly’s midgut and migration to the salivary glands,
where they can be transmitted to a new host during a subsequent
bite.
4.The sick student is not a direct source of infection for others
because African Trypanosomiasis requires a tsetse fly vector for
transmission. Direct transmission from person to person does not
occur without the vector.
5.Yes, this disease can be classified as a natural focus disease. It
is maintained in nature through a cycle involving the tsetse fly
vector and, for T. b. rhodesiense, animal reservoirs. Human infection
occurs incidentally when individuals enter the natural focus area and
are bitten by an infected tsetse fly. Both subspecies fit the definition
of a vector-borne disease with natural foci.
, Task 3.
A patient came to a urologist, he complained of an excessive discharge from the
urethra, as well as burning sensation, itchiness and pain during urination. The
microscopy of the discharge sample showed unicellular pear-shaped organisms,
25mcm in size, which had four free flagella of the same length. The axostyle was
visible at the posterior end of the body as a spine.
1. Which parasite was detected? Write the English and the full Latin name of
this parasitic species.
2. What was the transmission route?
3. Can the patient be the source of infection for the people around him? Explain
your answer.
4. Which morphological features of this parasite help to distinguish it from the
other species of the same genus?
5. Describe this organism according to the classifications of parasites.
Ans. 1. Vaginal trichomonas – Trichomonas vaginalis.
2. The infection occurred through contact, the mechanism is sexual
contact.
3. The patient is a direct source of infection for his sexual partners
since the infective stage of the parasite is the trophozoite which is
transmitted sexually.
4. The parasite cell is oval or spindle-shaped unlike intestinal and
oral trichomonas’ cell, it is 10-30 mcm in length. The nucleus Is
oval, with slightly pointed ends, located at the anterior widened end
