Nokea
In the South and Central America there can be found a species of trypanosomes that is the causative agent of Chagas disease. What animal is the infection carrier specific to this disease?
- A. Triatomine bug
- B. Mosquito
- C. Tsetse fly
- D. Cockroach
Correct Answer: A
Rationale: The correct answer is A: Triatomine bug. Triatomine bugs, also known as "kissing bugs," are the specific carrier of the trypanosomes that cause Chagas disease. These bugs transmit the parasite through their feces, which contain the infectious forms of the trypanosomes. When the bug bites a human or animal, it defecates near the bite wound, allowing the parasites to enter the bloodstream through the broken skin. Mosquitoes (B) transmit diseases like malaria and dengue fever, not Chagas disease. Tsetse flies (C) are known for transmitting African trypanosomiasis (sleeping sickness), not Chagas disease. Cockroaches (D) are not known to transmit Chagas disease.
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The complex of all biological processes/mechanisms responsible for the state of steady internal, physical and chemical conditions in the living systems and defense against all foreign agents is knows as:
- A. infection
- B. homeostasis
- C. immunity
- D. commensalism
Correct Answer: B
Rationale: The correct answer is B: homeostasis. Homeostasis refers to the process by which living organisms maintain a stable internal environment despite external changes. It involves various biological processes and mechanisms that regulate factors such as temperature, pH, and nutrient levels within narrow limits. This is crucial for the proper functioning of cells, tissues, and organs.
Now, let's analyze the other choices:
A: Infection - Infection refers to the invasion and multiplication of harmful microorganisms in the body, leading to illnesses. It is not the correct answer as it does not encompass the overall maintenance of internal conditions.
C: Immunity - Immunity is the body's ability to resist and fight off infections. While immunity is related to defense against foreign agents, it does not fully capture the concept of maintaining internal stability.
D: Commensalism - Commensalism is a type of symbiotic relationship between different species where one benefits without harming the other. It is not related to the overall regulation of
Infectious process is:
- A. Clinically manifested disease
- B. Infectious disease with typical symptoms
- C. Interrelation between the macro- and micro organism
- D. Ambulatory form of infection
Correct Answer: C
Rationale: Rationale:
1. Infectious process involves interactions between macro and microorganisms.
2. It is not limited to manifested diseases or typical symptoms.
3. The process can occur without leading to a full-blown infectious disease.
4. Choice C correctly captures the dynamic relationship between different organisms.
Summary:
- A: Incorrect - Infectious process is not solely about clinically manifested diseases.
- B: Incorrect - Not all infectious diseases have typical symptoms.
- D: Incorrect - Ambulatory form is a specific type, not encompassing all infectious processes.
Which organism produces a toxin that blocks neuromuscular transmission in cholinergic motor neurons:
- A. Shigella dysenteriae
- B. Clostridium tetani
- C. Corynebacterium diphtheria
- D. Clostridium botulinum
Correct Answer: D
Rationale: The correct answer is D: Clostridium botulinum. This bacterium produces botulinum toxin, which blocks neuromuscular transmission by inhibiting the release of acetylcholine at the neuromuscular junction. This leads to muscle weakness and paralysis. Shigella dysenteriae (A) causes dysentery but does not affect neuromuscular transmission. Clostridium tetani (B) produces tetanus toxin, which affects inhibitory neurons in the spinal cord, leading to muscle spasm. Corynebacterium diphtheriae (C) produces diphtheria toxin, which affects protein synthesis in cells, not neuromuscular transmission.
Which statements is NOT CORRECT: Treponema pallidum can be cultivated on:
- A. Artificial food media
- B. Cell lines
- C. Intratesticular in rabbits
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Artificial food media. Treponema pallidum is a fastidious bacterium that cannot be cultivated on artificial food media due to its complex nutritional requirements. It can be cultivated on cell lines and intratesticular in rabbits. Therefore, option A is incorrect. Option B and C are correct.
A patient with a productive cough and fever had a Gram-positive cocci isolated from a sputum sample. The bacteria were catalase-positive and coagulase-negative. What is the likely microorganism?
- A. Staphylococcus epidermidis
- B. Staphylococcus aureus
- C. Streptococcus pneumoniae
- D. Neisseria meningitidis
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus epidermidis.
1. Gram-positive cocci suggest a staphylococcal species.
2. Catalase-positive indicates it belongs to the Staphylococcus genus.
3. Coagulase-negative rules out Staphylococcus aureus.
4. Staphylococcus epidermidis is a common cause of infections in immunocompromised patients.
Summary:
- B: Staphylococcus aureus is coagulase-positive.
- C: Streptococcus pneumoniae is a Gram-positive diplococci.
- D: Neisseria meningitidis is a Gram-negative diplococci.