Parasitology Practice Questions

Q: A pregnant lady had no complaints but mild cervical lymphadenopathy in first trimester. She was prescribed spiramycin but she was noncompliant. Baby was born with hydrocephalus and intracerebral calcification. Which of these is likely cause ?

Toxoplasmosis. ***Toxoplasmosis*** - The combination of **hydrocephalus** and **intracerebral calcifications** in a newborn is highly characteristic of **congenital toxoplasmosis**. The mother's mild cervical lymphadenopathy in the first trimester, coupled with non-compliance to spiramycin (an agent used to limit vertical transmission), further supports this diagnosis. - While many maternal infections are asymptomatic, fetal infection can lead to severe consequences. **Spiramycin** is used to reduce the risk of transplacental transmission, but does not treat established fetal infection. *CMV* - **Congenital cytomegalovirus (CMV)** can also cause **intracerebral calcifications**, but these are typically **periventricular**, unlike the diffuse calcifications seen in toxoplasmosis. - CMV often presents with **microcephaly** rather than hydrocephalus, and can also involve symptoms like **sensorineural hearing loss** and hepatosplenomegaly. *Rubella* - **Congenital rubella syndrome** is characterized by the classic triad of **cataracts**, **sensorineural hearing loss**, and **congenital heart defects** (e.g., patent ductus arteriosus). - While it can cause some central nervous system abnormalities, **hydrocephalus** and **intracerebral calcifications** are not its primary or characteristic presentation. *Herpes* - **Congenital herpes simplex virus (HSV) infection** typically presents with skin vesicles, keratitis, and encephalitis. - While it can cause neurological complications, **hydrocephalus** and prominent **intracerebral calcifications** similar to those described are not the hallmark features.

Q: All of the following are known to cause biliary obstruction EXCEPT:

Ancylostoma. ***Ancylostoma*** - **Ancylostoma**, or **hookworm**, primarily infects the small intestine, causing **iron deficiency anemia** due to blood loss. - It does not directly obstruct the biliary tree as it does not migrate there. *Fasciola* - **Fasciola hepatica**, the **sheep liver fluke**, can migrate to the **biliary ducts** and cause inflammation, fibrosis, and obstruction. - Its presence can lead to **cholangitis**, **cholecystitis**, and **formation of gallstones**. *Ascariasis* - **Ascaris lumbricoides**, a large intestinal nematode, can **migrate from the gut** into the **biliary tree** through the ampulla of Vater. - This can cause **acute cholangitis**, **pancreatitis**, or even **biliary obstruction** due to the physical presence of the worms. *Clonorchis* - **Clonorchis sinensis**, the **Chinese liver fluke**, specifically inhabits the **biliary ducts** of its human host. - Chronic infection can lead to profound **biliary obstruction**, **cholangitis**, and is a significant risk factor for **cholangiocarcinoma**.

Q: Brain abscess in immunodeficient person is due to :

Toxoplasma gondii. ***Toxoplasma gondii*** - **Toxoplasma gondii** is a very common cause of **brain abscesses** (cerebral toxoplasmosis) in individuals with compromised immune systems, especially those with AIDS. - The parasite is usually latent in many people and reactivates when the immune system weakens. *Aspergillus* - While *Aspergillus* can cause central nervous system infections, including brain abscesses, this is usually seen in severely **neutropenic** or transplant patients. - *Aspergillus* typically invades via **hematogenous spread** from a primary pulmonary infection or directly from sinusitis. *Cryptococcus* - *Cryptococcus neoformans* is a significant cause of **meningitis** in immunocompromised patients, particularly those with HIV/AIDS. - While it can cause **cryptococcomas** (focal lesions), pure abscess formation is less common than with *Toxoplasma*. *Candida* - *Candida* species can cause **brain microabscesses** or multifocal lesions, especially in patients with disseminated candidiasis originating from prolonged hospitalization or indwelling catheters. - However, large, solitary brain abscesses are less typical for *Candida* compared to *Toxoplasma gondii*.

Q: Cyclops play an important role in the transmission of:

Dracunculiasis. ***Dracunculiasis*** - **Cyclops** (copepods) are the intermediate hosts for the guinea worm (**Dracunculus medinensis**), the causative agent of **dracunculiasis**. - Humans become infected by drinking water containing Cyclops that have ingested **Dracunculus larvae**. *Typhoid* - Typhoid fever is caused by **Salmonella typhi** and is transmitted through **feco-oral contamination** of food and water. - It does not involve Cyclops or any insect intermediate host in its transmission cycle. *Ancylostomiasis* - **Ancylostomiasis** (hookworm infection) is caused by **Ancylostoma duodenale** or **Necator americanus**. - Transmission occurs when **larvae penetrate the skin**, typically from contaminated soil, not through Cyclops. *Yellow fever* - Yellow fever is a viral disease transmitted to humans primarily through the bite of infected **Aedes mosquitoes**. - Cyclops are not involved in the transmission of this arbovirus.

Q: Diarrhea syndrome in an AIDS patient can be due to which of the following? a) Rota virus b) Cryptosporidium c) Adenovirus d) E. coli

Cryptosporidium. ***Cryptosporidium*** - **Cryptosporidium parvum** is a common cause of **chronic, severe, watery diarrhea** in AIDS patients due to their compromised immune system [1]. - Infection can lead to **malabsorption** and significant weight loss in immunocompromised individuals [1]. *Adenovirus* - While adenoviruses can cause **gastroenteritis**, particularly in children, they are generally not a primary cause of severe, chronic diarrhea in AIDS patients. - Other opportunistic pathogens are usually more prevalent and cause more severe disease in immunocompromised hosts. *Rota virus* - **Rotavirus** is a common cause of **acute gastroenteritis** in infants and young children worldwide. - While it can infect immunocompromised individuals, it typically causes self-limiting illness and is less likely than Cryptosporidium to cause persistent, severe diarrhea in AIDS patients. *E. coli* - Various strains of **Escherichia coli** can cause diarrhea, ranging from traveler's diarrhea (e.g., ETEC) to hemorrhagic colitis (e.g., EHEC). - While some E. coli infections can be severe, they are not specifically or predominantly linked to chronic diarrhea in AIDS patients in the way opportunistic pathogens like Cryptosporidium are.

Q: In a rural clinic, a 3-year-old girl child is brought by her mother and is emaciated. Her hemoglobin was 5 g/dL. The girl also has edema over her knees and ankles with discrete rash on her knees, ankles and elbows. The most likely worm infestation causing these manifestations is:

Hookworm. ***Hookworm*** - **Hookworm infection** (Ancylostoma duodenale/Necator americanus) leads to chronic blood loss from the intestines, causing **microcytic hypochromic anemia** and **severe emaciation** due to persistent nutrient loss and malabsorption. - The combination of severe **anemia (Hb 5 g/dL)**, **emaciation**, and **edema** (due to **hypoalbuminemia**, a consequence of protein-losing enteropathy and poor nutrition) is highly characteristic of hookworm infestation in children. - The **discrete rash** on pressure points (knees, ankles, elbows) may represent **ground itch** (pruritic papulovesicular rash at larval penetration sites) or dermatitis secondary to malnutrition and edema. *Roundworm* - **Ascaris lumbricoides** can cause malnutrition and growth delays, but typically does not lead to the severe anemia and edema seen here unless there is a massive infestation leading to intestinal obstruction or biliary obstruction. - Its primary impact is often related to **nutrient competition** and mechanical obstruction, not significant blood loss. *Pinworm* - **Enterobius vermicularis** (pinworm) infection primarily causes **perianal itching**, especially at night. - It does not typically cause systemic symptoms like **severe anemia**, **emaciation**, or **edema**, as it does not feed on blood or cause significant nutrient malabsorption. *Whipworm* - **Trichuris trichiura** (whipworm) can cause chronic dysentery, **rectal prolapse**, and **anemia** in heavy infections due to blood loss. - While it can contribute to **growth retardation** and anemia, it is less likely to cause the profound emaciation and edema described compared to hookworm, especially with a hemoglobin level of 5 g/dL, which points strongly to major chronic blood loss.

Q: The spike of fever in malaria is at the time of release of ?

Merozoites. ***Merozoites*** - The **fever spikes** characteristic of malaria coincide with the synchronized **rupture of infected red blood cells** [1] and the release of new **merozoites** into the bloodstream. - These released merozoites then invade new red blood cells [1], continuing the cycle and triggering the host's inflammatory response, leading to fever. *Sporozoites* - **Sporozoites** are the forms injected by the mosquito into the human host and travel to the liver. - Their release from infected liver cells as **merozoites** into the bloodstream does not directly cause the characteristic fever spikes. *Hypnozoites* - **Hypnozoites** are dormant forms of *Plasmodium vivax* and *P. ovale* that persist in the liver and are responsible for **relapses** [1] weeks or months after the initial infection. - They do not directly cause the acute fever spikes associated with the erythrocytic cycle. *None of the options* - This option is incorrect because the release of merozoites is directly responsible for the fever spikes in malaria.

Q: Delhi boil refers to:

L. tropica sore. ***L. tropica sore*** - Delhi boil is a common name for cutaneous **leishmaniasis**, specifically caused by **Leishmania tropica**. - This condition presents as a **skin lesion** or sore, primarily in endemic regions like Delhi. *Solar Keratosis* - Solar keratosis is a **precancerous skin lesion** caused by long-term exposure to ultraviolet (UV) radiation from the sun. - It presents as a **rough, scaly patch** on sun-exposed areas and is not associated with parasitic infection. *Venereal ulcer* - A venereal ulcer is a **genital sore** typically caused by sexually transmitted infections (STIs) such as syphilis, herpes, or chancroid. - These ulcers are localized to the genital area and have a different etiology and clinical presentation than Delhi boil. *Malignant pustule* - A malignant pustule is a term sometimes used historically to describe **anthrax skin lesions** due to their necrotic and often black center, but more generally refers to a pustular lesion with malignant or highly aggressive characteristics. - It is not a synonym for Delhi boil, which is a parasitic infection with a distinct clinical course and etiology.

Q: Which among the following doesn't enter human body skin?

Trichinella. ***Trichinella*** - **Trichinella** species are acquired through ingestion of **undercooked meat** containing encysted larvae, primarily from pigs or wild game. They do not penetrate the skin. - The larvae mature in the intestine and then migrate to skeletal muscle, forming **cysts**. *Necator* - **Necator americanus** (New World hookworm) larvae invade the human body by **penetrating intact skin**, typically on the feet. - This invasion causes a characteristic **pruritic rash** known as "ground itch." *Strongyloides* - **Strongyloides stercoralis** larvae penetrate the skin, usually through the **feet**, to initiate infection in humans. - It is unique among intestinal nematodes due to its ability to cause **autoinfection**. *Ancylostoma* - **Ancylostoma duodenale** (Old World hookworm) larvae also enter the human body by **penetrating intact skin**, similar to Necator. - Skin penetration by Ancylostoma larvae can also lead to **ground itch**.

Q: All the following organisms can cause arthritis except

A filarial worm causing lymphatic filariasis. ***A filarial worm causing lymphatic filariasis*** - While **filarial infections** can cause lymphatic obstruction and systemic inflammation, they do not directly cause **arthritis**. Joint involvement is not a typical manifestation of lymphatic filariasis. - The primary pathology in **lymphatic filariasis** involves the lymphatic system, leading to lymphedema, hydrocele, and elephantiasis, rather than joint inflammation. *A parasitic worm causing dracunculiasis* - **Dracunculiasis**, caused by *Dracunculus medinensis* (Guinea worm), can lead to **arthritis** as the migrating worm or its lesions near joints cause significant inflammation and secondary bacterial infection. - The worm's migration and eventual emergence from the skin, often near joints, cause intense pain and an inflammatory response that can involve the joint space. *A tapeworm causing hydatid disease* - **Hydatid disease**, caused by *Echinococcus granulosus*, can form **hydatid cysts** in various tissues, including bone and occasionally periarticular soft tissues. - These cysts can erode into joints or cause a significant inflammatory reaction mimicking **arthritis** if they rupture or impinge on joint structures. *A protozoan causing malaria* - **Plasmodium species** causing malaria can trigger **reactive arthritis** through immune-mediated mechanisms, particularly in chronic or severe infections. - Arthralgias and frank arthritis have been documented in malaria cases, often involving multiple joints with synovial inflammation and immune complex deposition.

Question 1

A pregnant lady had no complaints but mild cervical lymphadenopathy in first trimester. She was prescribed spiramycin but she was noncompliant. Baby was born with hydrocephalus and intracerebral calcification. Which of these is likely cause ?

Accepted Answer

Toxoplasmosis

Answer

CMV

Answer

Rubella

Answer

Herpes

Question 2

All of the following are known to cause biliary obstruction EXCEPT:

Accepted Answer

Ancylostoma

Answer

Fasciola

Answer

Ascariasis

Answer

Clonorchis

Question 3

Brain abscess in immunodeficient person is due to :

Accepted Answer

Toxoplasma gondii

Answer

Aspergillus

Answer

Cryptococcus

Answer

Candida

Question 4

Cyclops play an important role in the transmission of:

Accepted Answer

Dracunculiasis

Answer

Typhoid

Answer

Ancylostomiasis

Answer

Yellow fever

Question 5

Diarrhea syndrome in an AIDS patient can be due to which of the following? a) Rota virus b) Cryptosporidium c) Adenovirus d) E. coli

Accepted Answer

Cryptosporidium

Answer

Adenovirus

Answer

Rota virus

Answer

E. coli

Question 6

In a rural clinic, a 3-year-old girl child is brought by her mother and is emaciated. Her hemoglobin was 5 g/dL. The girl also has edema over her knees and ankles with discrete rash on her knees, ankles and elbows. The most likely worm infestation causing these manifestations is:

Accepted Answer

Hookworm

Answer

Roundworm

Answer

Pinworm

Answer

Whipworm

Question 7

The spike of fever in malaria is at the time of release of ?

Accepted Answer

Merozoites

Answer

Sporozoites

Answer

Hypnozoites

Answer

None of the options

Question 8

Delhi boil refers to:

Accepted Answer

L. tropica sore

Answer

Solar Keratosis

Answer

Venereal ulcer

Answer

Malignant pustule

Question 9

Which among the following doesn't enter human body skin?

Accepted Answer

Trichinella

Answer

Necator

Answer

Strongyloides

Answer

Ancylostoma

Question 10

All the following organisms can cause arthritis except

Accepted Answer

A filarial worm causing lymphatic filariasis

Answer

A parasitic worm causing dracunculiasis

Answer

A tapeworm causing hydatid disease

Answer

A protozoan causing malaria

Parasitology — MCQs

Parasitology — MCQs

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