Zoonotic Diseases

Zoonotic Diseases Indian Medical PG Question 1: Match List-I with List-II and select the correct answer using the code given below the Lists:

• A. A→1 B→4 C→2 D→3
• B. A→1 B→2 C→4 D→3 (Correct Answer)
• C. A→4 B→3 C→2 D→1
• D. A→1 B→2 C→3 D→4

Zoonotic Diseases Explanation: ***A→1 B→2 C→4 D→3*** - This option correctly matches each disease with its primary characteristic: **Anthrax** is caused by *Bacillus anthracis*, **Leptospirosis** is known as **Weil's disease** (in its severe form), **Yellow fever** causes **jaundice** (hence the name "yellow"), and **Japanese encephalitis** is transmitted by **mosquito vector** (Culex species). - All pairings are medically accurate and represent the most distinctive features of each disease. *A→1 B→4 C→2 D→3* - While it correctly links **Anthrax** to *Bacillus anthracis* and **Japanese encephalitis** to **mosquito vector**, it makes critical errors with the middle two diseases. - **B→4** incorrectly pairs **Leptospirosis** with **jaundice** - while jaundice can occur in severe leptospirosis, this is not its defining characteristic or eponym (that would be Weil's disease). - **C→2** incorrectly pairs **Yellow fever** with **Weil's disease** - these are completely unrelated; Yellow fever is a flavivirus infection characterized by jaundice, not Weil's disease (which is leptospirosis). *A→4 B→3 C→2 D→1* - This option contains multiple fundamental errors in disease-characteristic matching. - **A→4** incorrectly pairs **Anthrax** with **jaundice** - Anthrax typically presents with cutaneous lesions (eschar), pulmonary, or GI symptoms, not jaundice. - **B→3** incorrectly pairs **Leptospirosis** with **mosquito vector** - Leptospirosis is transmitted through contact with water/soil contaminated with infected animal urine, not by mosquitoes. - The other pairings are also incorrect, making this option entirely wrong. *A→1 B→2 C→3 D→4* - This option correctly links **Anthrax** to *Bacillus anthracis* and **Leptospirosis** to **Weil's disease**, but makes errors in the last two pairings. - **C→3** incorrectly pairs **Yellow fever** with **mosquito vector** - while Yellow fever IS transmitted by mosquitoes (Aedes aegypti), this ignores that option 3 should go with Japanese encephalitis, and Yellow fever's most distinctive feature is jaundice (option 4). - **D→4** incorrectly pairs **Japanese encephalitis** with **jaundice** - JE is a neurological infection without jaundice as a primary feature.

Zoonotic Diseases Indian Medical PG Question 2: 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 ?

• A. 2 and 3 only (Correct Answer)
• B. 1 and 2
• C. 2, 3 and 4
• D. 3 and 4 only

Zoonotic Diseases Explanation: ***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.

Zoonotic Diseases Indian Medical PG Question 3: 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)

Zoonotic Diseases 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]

Zoonotic Diseases Indian Medical PG Question 4: Anthropo-Zoonoses are all except -

• A. Guinea worm infestation (Correct Answer)
• B. Hydatid cyst
• C. Plague
• D. Rabies

Zoonotic Diseases Explanation: ***Guinea worm infestation*** - Guinea worm disease, caused by **Dracunculus medinensis**, is a **human-specific disease** and is not transmitted from animals to humans. - Humans acquire the infection by drinking **contaminated water** containing copepods (water fleas) infected with larvae. *Hydatid cyst* - Hydatid disease is a **zoonosis caused by Echinococcus tapeworms**, primarily acquired through contact with infected dog feces. - Humans are an **accidental intermediate host**, developing cysts in organs like the liver and lungs. *Plague* - Plague is a **zoonosis caused by Yersinia pestis**, primarily transmitted from **rodents to humans** via infected flea bites. - Various animal reservoirs, especially **wild rodents**, play a crucial role in maintaining the disease cycle. *Rabies* - Rabies is a severe **zoonotic viral disease** transmitted to humans primarily through the saliva of **infected animals**, typically via a bite. - **Dogs are the most common source of human rabies infections**, but other mammals can also transmit the virus.

Zoonotic Diseases Indian Medical PG Question 5: Which of the following is classified as a Category A bioterrorism agent?

• A. Clostridium perfringens
• B. NIPAH virus
• C. Bacillus anthracis (Correct Answer)
• D. Coxiella burnetii

Zoonotic Diseases Explanation: ***Bacillus anthracis*** - **Anthrax**, caused by *Bacillus anthracis*, is a prime example of a Category A bioterrorism agent due to its high mortality, ease of dissemination, and potential for major public health impact. - Category A agents pose the **greatest threat** to public health and national security. *Clostridium perfringens* - *Clostridium perfringens* is classified as a **Category B bioterrorism agent**. - While it causes **gas gangrene** and food poisoning with moderate severity, it lacks the **high transmissibility** and widespread impact characteristic of Category A agents. *NIPAH virus* - **Nipah virus** is classified as a Category C priority pathogen. - It has the potential for high morbidity and mortality, but its **epidemiological characteristics** (e.g., lower transmissibility than Category A agents) preclude its inclusion in Category A. *Coxiella burnetii* - *Coxiella burnetii*, the causative agent of **Q fever**, is classified as a Category B bioterrorism agent. - Category B agents are moderately easy to disseminate and can cause **moderate morbidity** and low mortality, which is less severe than Category A agents.

Zoonotic Diseases Indian Medical PG Question 6: Most sensitive test for detecting microfilariae?

• A. Membrane filtration technique (Correct Answer)
• B. Diethylcarbamazine (DEC) challenge test
• C. Fluorescence-based immunoassay
• D. Thick blood smear

Zoonotic Diseases Explanation: ***Membrane filtration technique*** - The **membrane filtration technique** is considered the most sensitive test for detecting **microfilariae** because it concentrates microfilariae from a larger volume of blood (typically 1 mL or more) onto a filter membrane, increasing detection rates, especially in low-parasite density infections. - This method physically traps the microfilariae, allowing for microscopic examination of the concentrated sample after staining, which enhances visualization. *Diethylcarbamazine (DEC) challenge test* - The **DEC challenge test** uses **diethylcarbamazine** to provoke the release of microfilariae into the peripheral blood, especially in cases of occult filariasis or when microfilaria numbers are low. - While it can be useful in certain diagnostic situations, it is **less sensitive** than membrane filtration for directly detecting circulating microfilariae and carries the risk of inducing severe adverse reactions due to rapid parasite killing. *Fluorescence-based immunoassay* - **Fluorescence-based immunoassays** detect **antigens** or **antibodies** related to filarial infection, providing evidence of exposure or active infection. - While valuable for diagnosis, especially in antibody detection for chronic or occult infections, they do not directly detect live microfilariae and thus are not the most sensitive method for *detecting microfilariae themselves*. *Thick blood smear* - A **thick blood smear** is a common and quick method for detecting microfilariae by examining a drop of blood for their presence. - However, it is **less sensitive** than the membrane filtration technique, particularly in persons with low microfilaremia, as it examines a much smaller volume of blood.

Zoonotic Diseases Indian Medical PG Question 7: Due to which of the following does seasonal trend of a disease occur? 1. Vector variation 2. Environmental factors 3. Change in herd immunity Select the correct answer using the code given below:

• A. 1, 2 and 3 (Correct Answer)
• B. 2 and 3 only
• C. 1 and 3 only
• D. 1 only

Zoonotic Diseases Explanation: ***1, 2 and 3*** - **Vector variation** (e.g., mosquito populations increasing during warmer months) is a critical factor causing seasonal patterns in vector-borne diseases like malaria, dengue, and Japanese encephalitis. - **Environmental factors** such as temperature, humidity, and rainfall directly affect pathogen survival, vector breeding, transmission efficiency, and host susceptibility, leading to characteristic seasonal patterns (e.g., respiratory infections in winter, diarrheal diseases in summer). - **Changes in herd immunity** can contribute to temporal disease patterns, though this factor more commonly drives long-term cyclical patterns (multi-year cycles) rather than short-term seasonal variations. The accumulation of susceptible individuals (through births) and waning immunity can influence disease occurrence patterns over time. *2 and 3 only* - This option incorrectly excludes **vector variation**, which is a primary determinant of seasonality for many infectious diseases, particularly arthropod-borne infections. - Vector activity shows marked seasonal fluctuations that directly correlate with disease incidence. *1 and 3 only* - This option incorrectly excludes **environmental factors**, which are fundamental drivers of seasonal disease patterns. - Temperature, humidity, precipitation, and other climatic variables directly influence pathogen viability, vector ecology, and human behavioral patterns that affect disease transmission. *1 only* - This option is too restrictive, considering only **vector variation** while neglecting the significant contributions of **environmental factors** and **temporal changes in population immunity** to disease occurrence patterns. - Seasonal trends result from complex interactions among multiple factors.

Zoonotic Diseases Indian Medical PG Question 8: What is the purpose of 'ring vaccination' in disease control?

• A. A strategy to create lesions for disease identification.
• B. Vaccination administered within a specific radius around a confirmed case. (Correct Answer)
• C. Vaccination given to all individuals in a one-mile radius of a case.
• D. A mass vaccination campaign targeting the entire population of a region.

Zoonotic Diseases Explanation: ***Vaccination administered within a specific radius around a confirmed case.*** - **Ring vaccination** is a targeted disease control strategy that focuses on immunizing individuals who are *most likely to be infected* due to direct or indirect contact with a confirmed case. - This strategy creates a **"ring" of immunized individuals** around the infected person, forming a protective barrier to prevent further disease transmission. - Commonly used for diseases like **smallpox** (historical eradication) and **Ebola outbreaks**, where rapid containment is critical. *A strategy to create lesions for disease identification.* - Ring vaccination is a **preventive immunization strategy**, not a diagnostic method. - Lesions are symptoms of infection, not artificially created for disease identification purposes. *Vaccination given to all individuals in a one-mile radius of a case.* - While ring vaccination does involve proximity-based targeting, the **"one-mile radius" is too specific and inflexible**. - The actual radius is determined by **disease transmissibility, contact tracing results, and population density**, not a fixed distance. *A mass vaccination campaign targeting the entire population of a region.* - Ring vaccination is a **targeted, focused strategy**, not a mass campaign. - Mass vaccination campaigns aim for broad population coverage, whereas ring vaccination specifically targets **contacts and contacts of contacts** around known cases for rapid containment.

Zoonotic Diseases Indian Medical PG Question 9: Herd immunity is not seen in

• A. Poliomyelitis
• B. Tetanus (Correct Answer)
• C. Measles
• D. Diphtheria

Zoonotic Diseases Explanation: ***Tetanus*** - Herd immunity is not achieved in tetanus because it is caused by toxins produced by the bacterium *Clostridium tetani*, which is found in the environment (e.g., soil) and is not transmitted from person to person. - Protection against tetanus relies on individual vaccination, as the presence of immune individuals does not prevent others from being exposed to the environmental pathogen. *Poliomyelitis* - **Poliomyelitis** is a highly contagious disease caused by a virus that spreads from person to person, primarily through the fecal-oral route. - High vaccination rates create **herd immunity**, protecting unvaccinated individuals by reducing the circulation of the virus in the population. *Measles* - Measles is one of the most contagious diseases, spread through airborne droplets from person to person. - **Herd immunity** is crucial for controlling measles outbreaks; a high percentage of vaccinated individuals protects vulnerable populations, such as infants too young for vaccination. *Diphtheria* - Diphtheria is a bacterial infection spread through respiratory droplets from person to person. - **Herd immunity** is effective in preventing diphtheria outbreaks, as a significant proportion of immune individuals limits the spread of the causative bacterium, *Corynebacterium diphtheriae*.

Zoonotic Diseases Indian Medical PG Question 10: Which organism does not require a vector for transmission?

• A. Rickettsia rickettsii
• B. Borrelia recurrentis
• C. Rickettsia prowazekii
• D. Coxiella burnetii (Correct Answer)

Zoonotic Diseases Explanation: ***Coxiella burnetii*** - This organism causes **Q fever** and does not require an arthropod vector; it is primarily transmitted via **aerosols** from infected animals. - Humans usually acquire the infection by inhaling **contaminated aerosols** from infected livestock (cattle, sheep, goats). *Rickettsia prowazekii* - This bacterium is the causative agent of **epidemic typhus** and is transmitted by the **human body louse** (*Pediculus humanus corporis*). - The louse acts as a **biological vector**, acquiring the organism from an infected human and transmitting it through its feces, which are then scratched into the skin. *Rickettsia rickettsii* - This organism causes **Rocky Mountain Spotted Fever (RMSF)** and is transmitted by **ticks**, primarily the American dog tick (*Dermacentor variabilis*) and the Rocky Mountain wood tick (*Dermacentor andersoni*). - Ticks serve as both **vectors** and **reservoirs** for *Rickettsia rickettsii*. *Borrelia recurrentis* - This spirochete causes **louse-borne relapsing fever** and is transmitted by the **human body louse** (*Pediculus humanus corporis*). - Transmission occurs when the louse is crushed and its hemolymph, containing the bacteria, comes into contact with broken skin or mucous membranes.

Zoonotic Diseases Flashcard 1 of 10

Question: _____ is an obligate intracellular bug that forms spores in animal feces

Answer: Coxiella burnetti

Zoonotic Diseases Flashcard 2 of 10

Question: How is Yersinia enterocolitica transmitted (3)?_____

Answer: Pet feces (puppies)

Zoonotic Diseases Flashcard 3 of 10

Question: The Ixodes tick is involved in the transmission of _____, Anaplasma spp., and Babesia

Answer: Borrelia burgdorferi

Zoonotic Diseases Flashcard 4 of 10

Question: _____, Francisella, and Yersinia pestis are zoonotic falcultative intracellular bacteria that can live in macrophages

Answer: Brucella*

Zoonotic Diseases Flashcard 5 of 10

Question: Brucella spp. is a facultative intracellular zoonotic bacteria found within _____ of the reticuloendothelial system

Answer: macrophages

Zoonotic Diseases Flashcard 6 of 10

Question: The image shows the _____ which is responsible for the transmission of Orientia tsutsugamushi.

Answer: trombiculid mite

Zoonotic Diseases Flashcard 7 of 10

Question: Hard tick can cause _____

Answer:

Zoonotic Diseases Flashcard 8 of 10

Question: f1a2c5c4886a4dfb832107b2ab3414d9-ao-7

Answer: rickettsial disease and vectors

Extra Information: typhus

Zoonotic Diseases Flashcard 9 of 10

Question: f1a2c5c4886a4dfb832107b2ab3414d9-ao-3

Answer: rickettsial disease and vectors

Extra Information: typhus

Zoonotic Diseases Flashcard 10 of 10

Question: f1a2c5c4886a4dfb832107b2ab3414d9-ao-1

Answer: rickettsial disease and vectors

Extra Information: typhus