Emerging and Re-emerging Infections — MCQs
Zoonotic diseases are -
A man with chills, fever, and headache is thought to have "atypical" pneumonia. History reveals that he raises chickens, and that approximately 2 weeks ago he lost a large number of them to an undiagnosed disease. Which of the following is the most likely diagnosis of this man's condition?
What is the first step an epidemiologist takes in an epidemic investigation?
Which diseases are infectious but not communicable?
All of the following conditions are immediate priorities in the WHO's "Vision -2020: The Right to sight" except:
Which of the following is the true statement regarding measures to prevent typhoid transmission in the community?
The Roll Back Malaria programme focused mainly on
Which of the following diseases is not under surveillance in the Integrated Disease Surveillance Project (P-Form)?
Which disease was removed from active WHO surveillance requirements following its global eradication?
Emergency or re-emergence seen in which of the following organisms? a) Polio virus b) Measles virus c) Nipah virus d) West Nile virus e) Ebola virus
Emerging and Re-emerging Infections Indian Medical PG Practice Questions and MCQs
Question 1: Zoonotic diseases are -
- A. Anthrax
- B. Plague
- C. Salmonellosis
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Anthrax**, **Plague**, and **Salmonellosis** are all well-established examples of zoonotic diseases, which are infections naturally transmitted between vertebrate animals and humans. - These diseases represent a diverse spectrum of bacterial infections with significant public health implications worldwide. **Anthrax** - Caused by *Bacillus anthracis*, a spore-forming bacterium naturally found in soil that primarily affects livestock and wild herbivores. - Humans acquire infection through contact with infected animals or contaminated animal products (hides, wool, meat). - Clinical forms include cutaneous (most common), inhalational (most severe), and gastrointestinal anthrax. - Remains an important occupational hazard for veterinarians, farmers, and those handling animal products. **Plague** - Caused by *Yersinia pestis*, maintained in nature through rodent-flea cycles. - Transmission to humans occurs primarily via bites from infected fleas or direct contact with infected animals. - Historically responsible for devastating pandemics including the Black Death. - Clinical manifestations include bubonic (most common), pneumonic (person-to-person transmission possible), and septicemic plague. **Salmonellosis** - Caused by non-typhoidal *Salmonella* species, commonly colonizing the intestines of various animals including poultry, cattle, reptiles, and pets. - Humans typically acquire infection through consumption of contaminated food (undercooked meat, eggs, unpasteurized dairy) or direct animal contact. - Presents as acute gastroenteritis with diarrhea, fever, and abdominal cramps. - One of the most common foodborne zoonotic infections globally.
Question 2: A man with chills, fever, and headache is thought to have "atypical" pneumonia. History reveals that he raises chickens, and that approximately 2 weeks ago he lost a large number of them to an undiagnosed disease. Which of the following is the most likely diagnosis of this man's condition?
- A. Leptospirosis
- B. Relapsing fever
- C. Anthrax
- D. Ornithosis (Correct Answer)
Explanation: ***Ornithosis*** - The patient's symptoms of **chills, fever, headache, and atypical pneumonia**, combined with a history of **raising chickens** that recently died from an undiagnosed disease, are highly suggestive of ornithosis (also known as **psittacosis** or **parrot fever**). [2], [3] - This zoonotic infection is caused by **Chlamydophila psittaci** and is transmitted to humans through inhalation of contaminated aerosols from infected birds (poultry, parrots, pigeons). [2] *Leptospirosis* - **Leptospirosis** is typically associated with exposure to **contaminated water or soil** with animal urine, not direct contact with sick poultry. - While it can cause fever and headache, it often presents with **jaundice, renal failure, and hemorrhagic manifestations**, which are not mentioned here. *Relapsing fever* - **Relapsing fever** is characterized by **recurrent episodes of fever** separated by afebrile periods, caused by **Borrelia** species transmitted by lice or ticks. - The clinical presentation does not align with the typical course or epidemiological link to sick chickens. *Anthrax* - **Inhalational anthrax** can cause severe respiratory symptoms and fever but is primarily associated with exposure to **Bacillus anthracis spores**, often from infected livestock (cattle, sheep) or bioweapon exposure. [1] - The rapid death of a large number of chickens and the patient's "atypical pneumonia" do not fit the typical presentation or common transmission routes of anthrax. [1]
Question 3: What is the first step an epidemiologist takes in an epidemic investigation?
- A. Confirm the diagnosis (Correct Answer)
- B. Identify the prone people
- C. Identify the causative factors
- D. Identify the cases
Explanation: ***Confirm the diagnosis*** - The initial and most crucial step is to **confirm the diagnosis** of the disease in question to ensure that the reported cases are indeed suffering from the same condition. - This step helps to avoid misclassification and ensures the investigation focuses on a specific, confirmed health problem. *Identify the cases* - While essential, **identifying cases** usually follows initial diagnostic confirmation, as you need a clear case definition based on a confirmed diagnosis to correctly identify who is a case. - This involves defining who is considered a case based on symptoms, laboratory results, and epidemiological links. *Identify the prone people* - **Identifying prone people** refers to determining the population at risk, which is a subsequent step after understanding the confirmed disease and its initial pattern. - This step typically falls under characterizing the distribution of the disease (person, place, time) in the investigation. *Identify the causative factors* - **Identifying causative factors** is a later stage in the investigation, often involving analytical studies to test hypotheses, which can only occur effectively once the diagnosis is confirmed and cases are clearly defined and counted. - This step aims to understand *why* the epidemic is occurring, after establishing *what* is occurring.
Question 4: Which diseases are infectious but not communicable?
- A. Tetanus (Correct Answer)
- B. Mumps
- C. Scarlet fever
- D. Measles
Explanation: **Key Concept:** Infectious diseases are caused by microorganisms, while communicable diseases can spread from person to person. Some diseases are infectious but NOT communicable. ***Correct: Tetanus*** - Tetanus is caused by toxins produced by *Clostridium tetani*, which typically enters the body through **wounds contaminated with soil or feces** - It is **infectious** because a microorganism causes the disease - It is **NOT communicable** as it **cannot be spread directly from person to person** - the bacteria must enter through environmental contamination - Classic example of infectious but non-communicable disease *Incorrect: Mumps* - Mumps is a **communicable disease** caused by the mumps virus, primarily spread through **respiratory droplets** from person to person - Leads to inflammation of **salivary glands**, especially the parotid glands - Both infectious AND communicable *Incorrect: Scarlet fever* - Scarlet fever is a **communicable bacterial infection** caused by group A *Streptococcus*, spread through **respiratory droplets** from person to person - Presents with a characteristic **red rash**, sore throat, and fever - Both infectious AND communicable *Incorrect: Measles* - Measles is a **highly communicable viral disease** transmitted through **airborne droplets** from person to person - Characterized by a distinctive **rash, fever, cough, coryza, and conjunctivitis** - Both infectious AND communicable
Question 5: All of the following conditions are immediate priorities in the WHO's "Vision -2020: The Right to sight" except:
- A. Cataract
- B. Epidemic conjunctivitis (Correct Answer)
- C. Onchocerciasis
- D. Trachoma
Explanation: ***Epidemic conjunctivitis*** - While **epidemic conjunctivitis** can cause significant discomfort and temporary vision impairment, it is generally **self-limiting** and rarely leads to permanent blindness. - It was not identified as one of the top five global causes of avoidable blindness targeted by the Vision 2020 initiative. *Cataract* - **Cataract** is the **leading cause of blindness** globally, accounting for approximately half of all cases. - It is a highly treatable condition through surgery, making it a critical priority for Vision 2020. *Onchocerciasis* - Also known as **river blindness**, onchocerciasis is a parasitic disease that causes severe visual impairment and blindness. - It is a significant public health problem in several regions, particularly in Africa, and was a key focus of Vision 2020 due to its widespread impact and the availability of preventive chemotherapy. *Trachoma* - **Trachoma** is the **leading infectious cause of blindness** worldwide, caused by *Chlamydia trachomatis*. - Given its preventable and treatable nature, and its prevalence in many impoverished areas, it was designated as one of the priority diseases under Vision 2020.
Question 6: Which of the following is the true statement regarding measures to prevent typhoid transmission in the community?
- A. Typhoid vaccine administration is the best method of preventing transmission.
- B. Person-to-person transmission is the primary mode of spread.
- C. Drug resistance in typhoid is not as big a problem as in TB.
- D. Hygiene practice and clean sanitation control are more important than the typhoid vaccine. (Correct Answer)
Explanation: ***Hygiene practice and clean sanitation control is more important than the typhoid vaccine.*** - **Improved sanitation**, safe water supplies, and adequate hygiene practices are fundamental in controlling the spread of **typhoid fever**, as the disease is primarily transmitted through the **oral-fecal route**. - While vaccines are an important tool, they offer only partial protection and must be combined with **robust public health infrastructure** and **sanitation measures** for effective prevention. *Typhoid vaccine administration is the best method of preventing transmission.* - Typhoid vaccines offer protection, but their effectiveness is not 100%, and they typically require **booster doses** - **Vaccination campaigns** are most effective when implemented alongside improvements in **water and sanitation infrastructure**, as vaccines alone cannot fully prevent transmission in areas with poor hygiene. *Person-to-person transmission is the primary mode of spread.* - While person-to-person transmission can occur, especially in settings with poor hygiene, the primary mode of spread for typhoid is through the **ingestion of food or water contaminated** with the feces of an infected person or carrier. - This emphasizes the crucial role of **water and food safety** rather than just focusing on direct person-to-person contact. *Drug resistance in typhoid is not as big a problem as in TB.* - **Antimicrobial resistance (AMR)** in typhoid fever, particularly to fluoroquinolones and extended-spectrum beta-lactamase (ESBL) producing strains, is a **significant and growing global health concern**, complicating treatment. - While TB also faces serious drug resistance issues, the escalating problem of **extensively drug-resistant (XDR)** and **multi-drug resistant (MDR)** typhoid strains makes it a substantial threat, impacting treatment options and increasing morbidity and mortality.
Question 7: The Roll Back Malaria programme focused mainly on
- A. IEC campaigns for community awareness
- B. Insecticide treated bed nets (Correct Answer)
- C. Development of larvivorous fishes for eradication of larvae.
- D. Presumptive treatment of malaria case
Explanation: ***Insecticide treated bed nets*** - The **Roll Back Malaria (RBM)** program, launched in 1998, focused significantly on key interventions including the promotion and distribution of **insecticide-treated nets (ITNs)**. - ITNs are highly effective in **preventing mosquito bites**, thus reducing malaria transmission, especially in vulnerable populations. *IEC campaigns for community awareness* - While **Information, Education, and Communication (IEC)** campaigns are crucial for health programs, they were a supportive component rather than the primary focus of RBM's core intervention strategy. - RBM emphasized **tangible interventions** with direct impact on disease transmission. *Development of larvivorous fishes for eradication of larvae* - The use of **larvivorous fish** is a form of biological control, which is typically part of **integrated vector management** but not the central pillar of RBM's strategy. - RBM prioritized interventions with **broad, immediate impact** across larger populations. *Presumptive treatment of malaria case* - **Presumptive treatment** (treating based on symptoms without laboratory confirmation) was an important aspect of early malaria control but not the main strategic thrust of the RBM initiative. - RBM's primary focus was on **prevention and rapid diagnosis/treatment** using effective antimalarials, and vector control strategies.
Question 8: Which of the following diseases is not under surveillance in the Integrated Disease Surveillance Project (P-Form)?
- A. Snake bite (Correct Answer)
- B. Acute respiratory tract infections
- C. Tuberculosis
- D. Leptospirosis
Explanation: ***Snake bite*** - While a public health concern, **snake bites** are generally not included in the list of diseases under routine surveillance by the Integrated Disease Surveillance Project (IDSP) P-Form, which focuses on infectious diseases with epidemic potential. - The IDSP primarily monitors for **communicable diseases**, outbreaks, and other public health threats requiring rapid detection and response. *Acute respiratory tract infections* - **Acute respiratory tract infections (ARIs)**, including severe acute respiratory infections (SARIs), are a major focus of IDSP surveillance due to their high transmissibility and potential for large-scale outbreaks. - Surveillance helps in detecting trends, identifying new pathogens, and implementing timely control measures. *Tuberculosis* - **Tuberculosis (TB)** is a priority disease for surveillance under the IDSP due to its high prevalence, chronic nature, and the need for continuous monitoring of incidence, prevalence, and treatment outcomes. - The IDSP plays a role in tracking TB cases and drug resistance patterns to inform national control programs. *Leptospirosis* - **Leptospirosis** is an emerging infectious disease with epidemic potential, especially in areas with poor sanitation and during floods, making it a crucial disease for IDSP surveillance. - Surveillance helps in early detection of outbreaks and implementation of control measures to prevent spread.
Question 9: Which disease was removed from active WHO surveillance requirements following its global eradication?
- A. Guinea worm
- B. Typhoid
- C. HIV/AIDS
- D. Smallpox (Correct Answer)
Explanation: ***Smallpox*** - Smallpox was **globally eradicated** in 1980 through a concerted vaccination effort, making it the first human disease eradicated. - Due to its eradication, it has been **removed from active WHO surveillance requirements** as it no longer poses a threat to public health. *Guinea worm* - While significant progress has been made in Guinea worm eradication, it has **not yet been fully eradicated**, with a few endemic areas remaining. - It is currently still subject to **active surveillance efforts** by the WHO to monitor progress towards elimination. *Typhoid* - Typhoid is caused by *Salmonella Typhi* and remains a significant public health issue, especially in areas with poor sanitation. - It is a **notifiable disease** and continuously monitored by the WHO and national health agencies, especially with concerns about **antimicrobial resistance**. *HIV/AIDS* - HIV/AIDS is a **global pandemic** with ongoing high prevalence and incidence rates worldwide, particularly in certain regions. - It is under **intensive surveillance and control programs** by the WHO, given its significant global health burden and lack of a definitive cure or vaccine for complete eradication.
Question 10: Emergency or re-emergence seen in which of the following organisms? a) Polio virus b) Measles virus c) Nipah virus d) West Nile virus e) Ebola virus
- A. abd
- B. Hepatitis B virus
- C. bde
- D. cde (Correct Answer)
Explanation: ***cde*** - **Nipah virus** is a well-known **emerging infectious disease** due to spillover from animal reservoirs. - **West Nile virus** is considered a **re-emerging pathogen** that has spread globally, causing outbreaks. - **Ebola virus** is famously associated with several **re-emergence events** in Africa, characterized by high fatality rates. *abd* - **Polio virus** is targeted for eradication and, while still circulating in some regions, is not typically classified as an emerging or re-emerging disease in the same context as the others. - **Measles virus** is a vaccine-preventable disease that can cause outbreaks due to waning immunity or unvaccinated populations, but its pattern is more of a persistent public health challenge rather than true emergence/re-emergence. *Hepatitis B virus* - **Hepatitis B virus** is a chronic global health burden but is not considered an emerging or re-emerging virus; it has been endemic for many decades. - Its transmission patterns and epidemiological profile are well-established. *bde* - **Measles virus**, as mentioned, is not typically categorized as an emerging or re-emerging infectious disease. - The combination here incorrectly groups measles with true emerging/re-emerging pathogens. *ade* - **Polio virus** is primarily a target for eradication, not an emerging or re-emerging pathogen. - This option incorrectly includes polio within the category of emerging/re-emerging diseases.
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