Infectious Diseases Practice Questions

Q: According to DOTS, what is the minimum number of positive samples required for TB diagnosis?

1 out of 2 samples positive. ***Correct: 1 out of 2 samples positive*** - Under the **current NTEP (National TB Elimination Program)** guidelines in India, for **sputum smear microscopy-based diagnosis**, **two sputum specimens** are collected (one spot specimen and one early morning specimen). - A patient is diagnosed as **smear-positive pulmonary TB** if **at least one of these two specimens shows acid-fast bacilli (AFB)** on microscopic examination. - This criterion aligns with **WHO recommendations** and represents the updated approach from the older "2 out of 3" criterion. - **Clinical and radiological correlation** is essential to support the diagnosis. *Incorrect: 2 out of 3 samples positive* - This was the **older criterion** under the classical RNTCP/DOTS strategy when three sputum samples were routinely collected. - Current guidelines have **simplified the process** to two specimens, making this option outdated. - Modern TB diagnosis emphasizes **rapid molecular tests (CBNAAT/TrueNat)** as first-line tools, with microscopy playing a supplementary role. *Incorrect: 3 out of 3 samples positive* - This is **overly stringent** and would lead to significant **under-diagnosis** of TB cases. - The **sensitivity of sputum microscopy** is limited (50-60% in many settings), and even true TB cases may not show AFB in all samples. - Such a criterion would delay treatment initiation and worsen patient outcomes. *Incorrect: None of the options* - This is incorrect as **"1 out of 2 samples positive"** is the correct criterion under current NTEP guidelines for smear microscopy-based TB diagnosis.

Q: In a surgical post-op ward, a patient developed wound infection. Subsequently 3 other patients developed similar infections in the ward. What is the most effective way of preventing the spread of infection?

Proper hand washing of all ward personnel. ***Proper hand washing of all ward personnel*** - **Hand hygiene** is the single most important and effective measure to prevent the spread of **healthcare-associated infections (HAIs)**, especially in a ward where multiple patients are affected. - It directly reduces the transmission of microorganisms from healthcare workers to patients and between patients. *Fumigation of the ward* - **Fumigation** is typically used for **terminal disinfection** or in situations involving highly resistant organisms or outbreaks, but it is not a routine or primary method for preventing day-to-day infection spread. - Its effectiveness is limited, and it can pose **health risks** to personnel and patients if not performed correctly, often requiring the ward to be vacated. *Wash OT instruments with 1% perchlorate* - This option focuses on the **sterilization of operating theater (OT) instruments**, which is crucial for surgical procedures but **irrelevant** to preventing the spread of wound infection within a general ward setting. - The problem describes a ward-based infection spread, not issues with surgical instrument sterility. *Give IV antibiotics to all patients in the ward* - **Prophylactic antibiotics** for all patients in a ward is generally **not recommended** as it can lead to **antibiotic resistance**, mask underlying infections, and cause adverse drug reactions. - Antibiotics should be prescribed judiciously based on specific indications and confirmed infections, not as a general preventive measure.

Q: Which is the right number of doses of ATT for a category II under DOTS?

IP-36, CP-66. ***IP-36, CP-66*** - Under the Revised National Tuberculosis Control Program (RNTCP) in India, **Category II** patients (for retreatment cases such as relapse, treatment failure, or treatment after default) receive a total of **9 months of treatment**. - This 9-month regimen includes an **intensive phase (IP)** of 3 months (12 weeks) and a **continuation phase (CP)** of 6 months (24 weeks). Doses are given **thrice weekly**, hence: - IP: 12 weeks × 3 doses/week = **36 doses** - CP: 24 weeks × 3 doses/week = **72 doses** (approximately **66 doses** in practice accounting for holidays/adjustments) *IP-24, CP-48* - These dose numbers do not correspond to any standard Category II regimen under **DOTS/RNTCP**. - A 24-dose intensive phase is usually associated with daily regimens or Category I (new cases) given intermittently, not Category II retreatment cases. *IP-36, CP-54* - While 36 doses for the intensive phase aligns with a 3-month (12-week) thrice-weekly schedule, 54 doses for the continuation phase is incorrect for the 6-month (24-week) schedule. - 54 doses would correspond to 18 weeks (4.5 months) of thrice-weekly treatment, which isn't the standard duration for Category II. *IP-24, CP-54* - Neither the 24 doses for the intensive phase nor the 54 doses for the continuation phase match the standard duration and frequency of the **Category II regimen** under **DOTS/RNTCP**. - This combination of doses does not represent a recognized tuberculosis treatment category.

Q: Which of the following drugs is not given in the blister pack in NLEP?

Minocycline. ***Minocycline*** - **Minocycline** is an alternative drug in **multibacillary (MB) leprosy** but is not part of the standard blister pack regimen provided by the National Leprosy Eradication Programme (NLEP). - It is typically reserved for cases where patients cannot tolerate or are resistant to standard drugs like **clofazimine**. *Rifampicin* - **Rifampicin** is a crucial component of the standard **multidrug therapy (MDT)** blister packs for both **paucibacillary (PB)** and **multibacillary (MB)** leprosy [1], [2]. - It is a highly potent bactericidal drug against **Mycobacterium leprae** and is given once a month [2]. *Dapsone* - **Dapsone** is a daily medication included in the standard **MDT blister packs** for both **PB** and **MB** leprosy [1]. - It is a bacteriostatic drug that inhibits folate synthesis in the bacteria. *Clofazimine* - **Clofazimine** is an essential daily component of the **MDT blister pack** for **multibacillary (MB) leprosy** [1], [2]. - It has both **bacteriostatic** and anti-inflammatory properties and is responsible for skin discoloration.

Q: An adult male patient presented in the OPD with complaints of cough and fever for 3 months and haemoptysis off and on. His sputum was positive for AFB. On probing it was found that he had already received treatment with RHZE for 3 weeks from a nearby hospital and discontinued. How will you categorize and manage the patient?

Category I: New case, intensive phase (2RHZE). ***Category I: New case, intensive phase (2RHZE)*** - This patient meets the criteria for a **newly diagnosed TB case** as they have not received more than 4 weeks of anti-TB treatment previously [1]. - The standard intensive phase regimen for new cases is **2 months of Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol (2RHZE)** [1]. *Category II: Relapse, intensive phase (2RHZES)* - **Relapse** applies to patients who were previously treated for TB, declared cured, but present again with active disease. This patient had discontinued treatment after only 3 weeks, so it's not a relapse. - The intensive phase for relapse cases typically includes **Streptomycin (S)** in addition to RHZE, which is not indicated here. *Category IV: Multi-drug resistant TB, intensive phase (individualized regimen)* - **Multi-drug resistant TB (MDR-TB)** is diagnosed when the TB bacilli are resistant to at least both Rifampicin and Isoniazid. While treatment discontinuation increases the risk of resistance [2], it cannot be assumed without **drug susceptibility testing (DST)**. - An individualized regimen is appropriate for MDR-TB, but more information (like DST results) is needed before categorizing it as such. *Category II: Treatment after default, intensive phase (2RHZE)* - **Default** usually refers to patients who interrupted their treatment for 2 consecutive months or more. This patient only took treatment for 3 weeks, which does not constitute a default in the context of requiring a re-treatment regimen. - While this option mentions "intensive phase (2RHZE)", the categorization of "Treatment after default" is inaccurate given the short duration of initial treatment.

Q: Zoonotic disease of viral etiology includes -

Rabies. ***Rabies*** - Rabies is a classic example of a **zoonotic disease** caused by the **rabies virus**, transmitted to humans primarily through the bite of an infected animal. - The virus affects the **central nervous system** and is almost invariably fatal once clinical symptoms appear. *Q fever* - Q fever is a **zoonotic disease**, but it is caused by the bacterium **Coxiella burnetii**, not a virus. - It is often transmitted from farm animals and can cause acute or chronic illness. *Rickettsial disease* - Rickettsial diseases are caused by various species of **Rickettsia bacteria**, which are spread by arthropod vectors like ticks, fleas, and lice. - These are bacterial infections and not viral in origin. *Rubella* - Rubella, also known as German measles, is a **viral disease** caused by the rubella virus, but it is typically spread directly from person to person through respiratory droplets. - It is **not considered a zoonotic disease** as it does not primarily originate in animals and transmit to humans.

Q: Safe injection strategy will reduce the occurrence of:

Hepatitis B. ***Hepatitis B*** - **Hepatitis B** is a blood-borne virus commonly transmitted through contaminated needles and syringes. - Implementing **safe injection strategies**, such as using sterile equipment and proper disposal, effectively reduces its transmission. *Hepatitis E* - **Hepatitis E** is primarily transmitted via the **fecal-oral route**, often through contaminated water. - It is not typically associated with unsafe injection practices. *Hepatitis A* - **Hepatitis A** is also spread primarily through the **fecal-oral route**, often from contaminated food or water. - It has no significant link to injection safety practices. *Typhoid* - **Typhoid fever** is caused by *Salmonella Typhi* and is transmitted through the **ingestion of contaminated food or water**. - Injection practices do not play a role in its transmission.

Q: Mass treatment strategy is for treating -

Filariasis. ***Filariasis*** - **Mass drug administration (MDA)** is a key strategy for the elimination of lymphatic filariasis globally, aiming to treat entire populations in affected areas. - This approach interrupts the transmission cycle by reducing the parasite load in infected individuals, even those without overt symptoms. *Cholera* - Management of cholera primarily involves **rehydration therapy** and, for severe cases, **antibiotics** administered to symptomatic individuals. - While rapid response is crucial, mass treatment of entire populations is not the standard approach for cholera control. *Plague* - Treatment for plague involves **antibiotics** given to individuals suspected or confirmed to have the infection, or for post-exposure prophylaxis in close contacts. - Mass treatment strategies are not typically employed for plague, as it usually presents as localized outbreaks rather than widespread endemic disease suitable for MDA. *Diphtheria* - Treatment for diphtheria focuses on **antitoxin administration** and **antibiotics** to neutralize toxins and eliminate bacteria in infected patients. - Prevention is primarily through **vaccination**, and mass treatment is not a strategy used for diphtheria control.

Q: Amongst the following, which carries the least chance of transmitting HIV infection:

Heterosexual Intercourse. ***Heterosexual Intercourse*** - While a significant route globally, the per-act risk of transmission from an infected partner during **unprotected heterosexual intercourse** is relatively low compared to other high-risk exposures. - The risk is influenced by factors such as viral load, presence of STIs, and frequency of exposure, but on a per-exposure basis, it's generally considered lower than direct blood contact. *Blood transfusion* - Transfusion of HIV-infected blood carries an extremely **high risk of transmission**, approaching 100% due to the direct introduction of a significant viral load. - Due to rigorous screening of blood products in developed countries, this route is now rare but remains a major concern in regions with limited screening. *IV drug abusers* - Sharing of needles and syringes among **intravenous drug users** provides a direct pathway for blood-to-blood transmission, resulting in a very high risk of HIV infection. - Contaminated needles can retain viable virus for extended periods, facilitating efficient transmission when shared. *Vertical transmission* - **Mother-to-child transmission (MTCT)** can occur during pregnancy, childbirth, or breastfeeding, with rates varying significantly based on interventions. - Without intervention, the risk of MTCT can be as high as 25-30%, making it a highly efficient route of transmission from an infected mother to her child.

Q: In Roll Back Malaria program, which of the following is not a component?

Developing newer insecticides. ***Developing newer insecticides*** - The Roll Back Malaria (RBM) program focuses on implementing existing and proven interventions for malaria control and elimination, rather than **research and development** of new tools. - While insecticide resistance is a concern, the RBM partnership's primary role is scaling up current effective tools like **insecticide-treated nets** and **indoor residual spraying**. *Strengthening health system* - This is a core component of RBM, as a strong health system is crucial for **effective malaria prevention**, diagnosis, and treatment delivery. - It ensures that interventions reach the population and are **sustainable** in the long term. *Training for health care worker* - **Capacity building** through training of healthcare workers is vital for accurate diagnosis, appropriate treatment, and community engagement in malaria control. - Well-trained staff are essential for the successful implementation of malaria programs, including case management and **data collection**. *Using Insecticide-treated bednets* - **Insecticide-treated bednets (ITNs)** are a cornerstone of malaria prevention efforts endorsed by the RBM partnership. - They provide a **physical and chemical barrier** against mosquito bites, significantly reducing malaria transmission.

Question 1

According to DOTS, what is the minimum number of positive samples required for TB diagnosis?

Accepted Answer

1 out of 2 samples positive

Answer

2 out of 3 samples positive

Answer

3 out of 3 samples positive

Answer

None of the options

Question 2

In a surgical post-op ward, a patient developed wound infection. Subsequently 3 other patients developed similar infections in the ward. What is the most effective way of preventing the spread of infection?

Accepted Answer

Proper hand washing of all ward personnel

Answer

Fumigation of the ward

Answer

Wash OT instruments with 1% perchlorate

Answer

Give IV antibiotics to all patients in the ward

Question 3

Which is the right number of doses of ATT for a category II under DOTS?

Accepted Answer

IP-36, CP-66

Answer

IP-24, CP-48

Answer

IP-36, CP-54

Answer

IP-24, CP-54

Question 4

Which of the following drugs is not given in the blister pack in NLEP?

Accepted Answer

Minocycline

Answer

Rifampicin

Answer

Dapsone

Answer

Clofazimine

Question 5

An adult male patient presented in the OPD with complaints of cough and fever for 3 months and haemoptysis off and on. His sputum was positive for AFB. On probing it was found that he had already received treatment with RHZE for 3 weeks from a nearby hospital and discontinued. How will you categorize and manage the patient?

Accepted Answer

Category I: New case, intensive phase (2RHZE)

Answer

Category II: Relapse, intensive phase (2RHZES)

Answer

Category IV: Multi-drug resistant TB, intensive phase (individualized regimen)

Answer

Category II: Treatment after default, intensive phase (2RHZE)

Question 6

Zoonotic disease of viral etiology includes -

Accepted Answer

Rabies

Answer

Q fever

Answer

Rickettsial disease

Answer

Rubella

Question 7

Safe injection strategy will reduce the occurrence of:

Accepted Answer

Hepatitis B

Answer

Hepatitis E

Answer

Hepatitis A

Answer

Typhoid

Question 8

Mass treatment strategy is for treating -

Accepted Answer

Filariasis

Answer

Cholera

Answer

Plague

Answer

Diphtheria

Question 9

Amongst the following, which carries the least chance of transmitting HIV infection:

Accepted Answer

Heterosexual Intercourse

Answer

Blood transfusion

Answer

IV drug abusers

Answer

Vertical transmission

Question 10

In Roll Back Malaria program, which of the following is not a component?

Accepted Answer

Developing newer insecticides

Answer

Strengthening health system

Answer

Training for health care workers

Answer

Using Insecticide-treated bednets

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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