Which of the following infectious disease is considered a newly emerging disease?

Correct Answer: A

Rationale: The correct answer is A: Hantavirus. Hantavirus is considered a newly emerging disease because it was first identified in the late 20th century. It is transmitted to humans through rodents and can lead to severe respiratory illness. Malaria, Tuberculosis, and Chlamydia are not considered newly emerging diseases as they have been known for centuries and continue to be prevalent worldwide. Therefore, based on the timeline of discovery and emergence, Hantavirus is the most recent infectious disease among the options provided.

Correct Answer: A

Rationale: The correct answer is A: Ziehl-Neelsen staining method. This method is used to detect acid-fast bacteria like Mycobacterium tuberculosis. Step-by-step rationale: 1. Acid-fast bacteria resist decolorization with acid-alcohol. 2. The red bacilli seen in the smear indicate acid-fast bacteria. 3. Ziehl-Neelsen stain uses carbol fuchsin to stain acid-fast bacteria red. 4. The blue background is likely the counterstain methylene blue. Incorrect choices: B: Gram stain is for categorizing bacteria into Gram-positive or Gram-negative, not specific for acid-fast bacteria. C: Giemsa stain is used for blood films and detecting parasites, not acid-fast bacteria. D: Neisser stain is not a standard microbiological staining method.

Correct Answer: A

Rationale: The correct answer is A: Toxoplasmosis. Toxoplasmosis is caused by the protozoan Toxoplasma gondii, which can be transmitted from mother to fetus during pregnancy leading to stillbirth and malformations. This parasite can cross the placenta and infect the fetus, causing severe complications. Leishmaniasis (B), Malaria (C), and Amebiasis (D) are not known to cause intrauterine death or malformations in the same way as Toxoplasmosis. Leishmaniasis is transmitted by sandflies, Malaria by mosquitoes, and Amebiasis by contaminated food or water.

Correct Answer: A

Rationale: The correct answer is A: Escherichia coli. E. coli is a Gram-negative rod that ferments lactose. It is a common cause of gastroenteritis presenting with fever and diarrhea. Salmonella typhi does not ferment lactose and causes typhoid fever. Shigella dysenteriae causes dysentery and does not ferment lactose. Proteus vulgaris does not typically cause gastroenteritis and is not known for lactose fermentation.

Correct Answer: A

Rationale: The correct answer is A: Hantavirus. Hantavirus is considered a newly emerging disease because it was first identified in the late 20th century. It is transmitted to humans through rodents and can lead to severe respiratory illness. Malaria, Tuberculosis, and Chlamydia are not considered newly emerging diseases as they have been known for centuries and continue to be prevalent worldwide. Therefore, based on the timeline of discovery and emergence, Hantavirus is the most recent infectious disease among the options provided.

Correct Answer: C

Rationale: The correct answer is C: Treatment. Tularin is a specific immunizing agent used for the treatment of tularemia. The purpose of tularin administration in this patient is to provide a targeted treatment against the suspected tularemia infection. It helps the patient's immune system to recognize and fight against the bacteria causing the disease. Explanation for other choices: A: Allergy diagnostics - Tularin is not used for allergy diagnostics, as it is specifically indicated for tularemia treatment. B: Prognosis for the disease - Tularin is not used to predict the outcome of the disease but rather to treat the infection. D: Treatment evaluation - Tularin is not used for evaluating the effectiveness of treatment but for actively treating the tularemia infection.

Correct Answer: A

Rationale: The correct answer is A because Staphylococcus aureus can develop resistance to penicillin over time due to the production of beta-lactamase enzymes. This resistance mechanism makes it no longer susceptible to penicillin. The other choices are correct: B) S. aureus can produce beta hemolysis, C) it produces various toxins like hemolysins, leucocidins, and enterotoxins, and D) it shows a positive catalase reaction due to the presence of catalase enzyme that converts hydrogen peroxide to water and oxygen.

Correct Answer: A

Rationale: The correct answer is A: Balantidium coli. This large ciliated protozoa with a kidney-shaped macronucleus is characteristic of Balantidium coli, an intestinal parasite known to cause foul-smelling diarrhea in humans. Balantidium coli is the only option among the choices that fits this specific description. Entamoeba histolytica causes amoebic dysentery, Giardia lamblia causes giardiasis, and Trichomonas hominis is a non-pathogenic protozoa found in the intestinal tract. Therefore, based on the morphology described in the question, Balantidium coli is the correct causative agent.

Correct Answer: A

Rationale: The correct answer is A: Staphylococcus aureus. This bacterium is Gram-positive cocci in clusters, catalase-positive, and coagulase-positive. Staphylococcus aureus is a common pathogen causing abscesses. Streptococcus pyogenes (B) is Gram-positive cocci in chains, not clusters. Micrococcus luteus (C) is catalase-positive but coagulase-negative. Enterococcus faecalis (D) is catalase-negative and coagulase-negative.