Infectious Diseases Practice Questions

Q: Effective disinfection of a typhoid patient's faecal matter can be done with

2% bleaching powder. ***2% bleaching powder*** - **Bleaching powder** (calcium hypochlorite) is a strong oxidizing agent that effectively disinfects faecal matter by destroying microbial cell structures. - A **2% solution** provides sufficient concentration of free chlorine to kill *Salmonella Typhi* and other pathogens in faeces. *2% phenol* - While **phenol** is an antiseptic and disinfectant, a 2% solution may not be strong enough for the effective and rapid disinfection of heavily contaminated faecal matter. - **Phenol** acts by denaturing proteins and disrupting cell membranes, but higher concentrations or longer contact times are generally needed for spore-forming or highly resistant organisms, though *Salmonella Typhi* is not spore-forming. *5% formalin* - **Formalin** (a solution of formaldehyde) is a powerful disinfectant and fixative, but it is typically used for sterilizing medical equipment or preserving biological specimens. - Its **strong fumes** and irritating nature make it less suitable for routine, large-scale disinfection of faecal matter due to safety concerns and logistical challenges. *5% cresol* - **Cresol** is a phenolic disinfectant that is more potent than phenol and is effective against a broad spectrum of microorganisms. - While effective, **cresol** is typically used in higher concentrations (like 5%) for disinfecting surfaces or specific wastes, and its pungent odor and potential toxicity might make it a less practical choice for general faecal disinfection compared to bleaching powder.

Q: Asymptomatic endometrial tuberculosis leading to infertility is categorized in which diagnostic category of DOTS?

Category III. ***Category III*** - Category III of the DOTS classification includes **newly diagnosed pulmonary smear-negative** and all forms of **extra-pulmonary tuberculosis**, provided they are not severe. - Endometrial tuberculosis, leading to infertility, is an **extra-pulmonary site** and is generally considered less severe compared to disseminated forms, thus falling into Category III. *Category II* - Category II is reserved for **previously treated cases** of tuberculosis, including relapse, treatment failure, or return after default. - This patient is described as having **asymptomatic** endometrial tuberculosis, implying a new diagnosis, not a retreatment case. *Category IV* - Category IV is used for cases of **chronic tuberculosis**, where the patient remains smear-positive after completing a retreatment regimen, often indicating drug-resistant TB. - This scenario describes a new diagnosis of extra-pulmonary TB, with no mention of prior treatment failures or chronic infection. *Category I* - Category I applies to **newly diagnosed pulmonary smear-positive** tuberculosis cases and severe forms of extra-pulmonary tuberculosis. - Asymptomatic endometrial tuberculosis, in this context, is neither pulmonary smear-positive nor typically considered a severe or life-threatening form of extra-pulmonary TB.

Q: To control Mansonia mosquitoes, the most effective method is:

Removal of water plants. ***Correct: Removal of water plants*** - **Mansonia** mosquitoes have a unique biological adaptation where their **larvae and pupae attach to the roots and stems of aquatic plants** (like *Pistia*, *Eichhornia*, water lettuce) to obtain oxygen through a specialized respiratory siphon - **Removal of aquatic vegetation** is the **most effective control method** because it eliminates the attachment sites essential for larval and pupal respiration - Without host plants, the larvae and pupae cannot obtain oxygen and die, making this the **gold standard** for Mansonia control - This method provides long-term control by eliminating the breeding habitat *Incorrect: Larvicidal insecticides* - While larvicidal insecticides are effective for many mosquito species, they are **less effective for Mansonia** mosquitoes - Since Mansonia larvae remain submerged and attached to plant roots (not coming to the surface for air), conventional larvicides have difficulty reaching them - The larvae's unique oxygen-obtaining mechanism makes them relatively resistant to surface-applied larvicides *Incorrect: Avoidance of water collections* - **Mansonia** mosquitoes breed in large, permanent water bodies with extensive aquatic vegetation (ponds, marshes, swamps) - These are natural habitats that cannot be easily eliminated - Unlike container-breeding mosquitoes (e.g., *Aedes*), avoidance of water collections is impractical and ineffective for Mansonia control *Incorrect: Oiling of water* - **Oiling the water surface** creates a film that prevents mosquito larvae from accessing atmospheric oxygen at the surface - This method works for species like **Anopheles** and **Culex** whose larvae breathe from the water surface - It is **completely ineffective against Mansonia** because their larvae obtain oxygen directly from **aquatic plant roots beneath the surface**, not from atmospheric air

Q: Consider the following diseases: 1. Yellow fever 2. Q fever 3. Chikungunya fever 4. Relapsing fever 5. Japanese encephalitis 6. Sleeping sickness Which of the above are transmitted by mosquitoes?

1, 3 and 5. ***1, 3 and 5*** - **Yellow fever** (1), **Chikungunya fever** (3), and **Japanese encephalitis** (5) are all **mosquito-borne viral diseases**. - These diseases are transmitted to humans through the bite of infected mosquitoes, primarily species like *Aedes* and *Culex*. *4, 5 and 6* - **Relapsing fever** (4) is transmitted by **ticks or lice**, not mosquitoes. - **Sleeping sickness** (6) is transmitted by the **tsetse fly**, not mosquitoes. *1, 2, 3, and 6* - **Q fever** (2) is caused by the bacterium *Coxiella burnetii* and is typically transmitted through **aerosols from infected animals**, not mosquitoes. - As mentioned, **Sleeping sickness** (6) is transmitted by the **tsetse fly**. *2, 3 and 5* - **Q fever** (2) is transmitted via **aerosols from infected animals**, not mosquitoes. - While Chikungunya fever (3) and Japanese encephalitis (5) are mosquito-borne, the inclusion of Q fever makes this option incorrect.

Q: A pregnant woman in third trimester having fever was diagnosed as a case of Falciparum malaria. Under the National Health Programme, which drug is recommended?

ACT only. **ACT only** - **Artemisinin-based Combination Therapy (ACT)** is the recommended first-line treatment for uncomplicated *P. falciparum* malaria in pregnant women during the second and third trimesters under national health programs [1]. - ACTs are generally considered safe and effective in these trimesters, providing rapid parasite clearance and preventing recrudescence [1]. *Only Quinine* - While quinine is effective against *P. falciparum* and can be used in pregnancy, it is often reserved for severe malaria or in cases where ACT is contraindicated [1]. - It has a higher incidence of side effects like **cinchonism** (tinnitus, headache, nausea) compared to ACT. *ACT accompanied by single dose of Primaquine on day 2* - **Primaquine** is an antimalarial drug used for radical cure of *P. vivax* and *P. ovale* to prevent relapse, and as a gametocytocide for *P. falciparum* [1]. - It is **contraindicated in pregnancy** due to the risk of inducing **hemolysis** in the fetus if they have glucose-6-phosphate dehydrogenase (G6PD) deficiency. *Chloroquine* - **Chloroquine** is largely ineffective against *P. falciparum* malaria in many endemic regions due to widespread **drug resistance**. - Its use is primarily limited to sensitive *P. vivax*, *P. ovale*, and *P. malariae* infections.

Q: Chandler’s index is used in the epidemiological studies of

Hookworm infection. **Hookworm infection** - Chandler's index is a specific epidemiological measure used to estimate the **worm burden** in a community, which is particularly relevant for **hookworm infections**. - It relates the **hemoglobin level** in a population to the prevalence of hookworm, as hookworms cause **iron deficiency anemia**. *Ascariasis* - While *Ascaris lumbricoides* is a common intestinal nematode, Chandler's index is not specifically developed for assessing its epidemiological impact. - Ascariasis typically causes **malnutrition** and occasional **bowel obstruction** rather than severe anemia as its primary public health impact. *Taenia solium infection* - *Taenia solium* causes **taeniasis** (intestinal tapeworm) and **cysticercosis** (tissue infection with larvae). - Its epidemiological study focuses on human-pig cycles and neurological manifestations, not anemia as measured by Chandler's index. *Guineaworm disease* - **Guineaworm disease** (dracunculiasis) is caused by *Dracunculus medinensis* and is acquired by drinking contaminated water. - Epidemiological studies focus on water sources and containment, and it does not typically cause **anemia** or use an index like Chandler's.

Q: A person has presented with history of dog-bite on the uncovered surface of his right leg. There is a minor abrasion without bleeding. Consider the following statements about management : 1. The bite should be taken as a category I contact with suspect animal 2. The bite requires local treatment of the wound 3. The person requires immediate vaccination 4. The person requires immediate administration of rabies immunoglobulin Which of the above statements are correct ?

2 and 3 only. ***2 and 3 only*** - A minor abrasion without bleeding falls under **Category II exposure** per WHO guidelines, requiring **local wound treatment** and **immediate vaccination**. - **Category II exposures** are defined as nibbling of uncovered skin, minor abrasions without bleeding, or scratches without bleeding. *1 and 2* - The bite described (minor abrasion without bleeding) is classified as **Category II exposure** by WHO, not Category I. - **Category I contact** involves touching or feeding an animal, or licks on intact skin, requiring **no post-exposure prophylaxis** as there is no breach of skin integrity. *2, 3 and 4* - While local wound treatment and vaccination are correct for Category II exposure, **rabies immunoglobulin (RIG)** is not indicated for Category II. - RIG is reserved for **Category III exposures**, which involve single or multiple transdermal bites or scratches, contamination of mucous membranes with saliva, or licks on broken skin. *3 and 4 only* - Immediate vaccination is correct, but **rabies immunoglobulin** is not necessary for a minor abrasion without bleeding (Category II exposure). - Administration of RIG is only indicated after **Category III exposures** due to the higher risk of rabies transmission.

Question 1

Effective disinfection of a typhoid patient's faecal matter can be done with

Accepted Answer

2% bleaching powder

Answer

2% phenol

Answer

5% formalin

Answer

5% cresol

Question 2

Asymptomatic endometrial tuberculosis leading to infertility is categorized in which diagnostic category of DOTS?

Accepted Answer

Category III

Answer

Category II

Answer

Category IV

Answer

Category I

Question 3

To control Mansonia mosquitoes, the most effective method is:

Accepted Answer

Removal of water plants

Answer

Avoidance of water collections

Answer

Larvicidal insecticides

Answer

Oiling of water

Question 4

Consider the following diseases:

1. Yellow fever
2. Q fever
3. Chikungunya fever
4. Relapsing fever
5. Japanese encephalitis
6. Sleeping sickness

Which of the above are transmitted by mosquitoes?

Accepted Answer

1, 3 and 5

Answer

4, 5 and 6

Answer

1, 2, 3, and 6

Answer

2, 3 and 5

Question 5

Which states are qualified as high prevalence states in the context of HIV/AIDS?

Accepted Answer

When prevalence in high risk groups is more than 5%, and 1% or more in antenatal women

Answer

When prevalence in high risk groups is less than 5%, and less than 1% in antenatal women

Answer

When prevalence in high risk groups is less than 5%, and more than 1% in antenatal women

Answer

When prevalence in high risk groups is more than 5%, and less than 1% in antenatal women

Question 6

A 20 year old male is diagnosed as a case of dengue fever at a Primary Health Centre. What are the suitable measures to be taken for the prevention and control of dengue in that area?

Accepted Answer

Case management for DF and DHF, isolation and individual protection from mosquitoes and environmental measures for elimination of breeding places

Answer

Case management for DF and DHF and vaccination

Answer

Case management for DF and DHF, isolation and individual protection from mosquitoes and vaccination

Answer

Case management for DF and DHF, isolation and individual protection from mosquitoes

Question 7

A pregnant woman in third trimester having fever was diagnosed as a case of Falciparum malaria. Under the National Health Programme, which drug is recommended?

Accepted Answer

ACT only

Answer

Only Quinine

Answer

ACT accompanied by single dose of Primaquine on day 2

Answer

Chloroquine

Question 8

Chandler’s index is used in the epidemiological studies of

Accepted Answer

Hookworm infection

Answer

Ascariasis

Answer

Taenia solium infection

Answer

Guineaworm disease

Question 9

With reference to meningococcal meningitis, which one of the following statements is not correct?

Accepted Answer

Treatment of cases has no significant effect in epidemiological pattern of disease

Answer

Fatality in untreated cases is 60%

Answer

Disease spreads mainly by droplet infection

Answer

Mass chemoprophylaxis causes immediate drop in incidence rate of cases

Question 10

A person has presented with history of dog-bite on the uncovered surface of his right leg. There is a minor abrasion without bleeding. Consider the following statements about management :

1. The bite should be taken as a category I contact with suspect animal
2. The bite requires local treatment of the wound
3. The person requires immediate vaccination
4. The person requires immediate administration of rabies immunoglobulin Which of the above statements are correct ?

Accepted Answer

2 and 3 only

Answer

1 and 2

Answer

2, 3 and 4

Answer

3 and 4 only

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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