A 37-year-old male was admitted to a hospital complaining of abdominal pain, difficulty in swallowing and breathing, constipation, and nausea. He developed respiratory failure and required endotracheal intubation and ventilation. Two days before, the patient consumed dried salted fish bought from an artisanal producer. Laboratory investigation for infectious pathogen was performed using Kitt-Tarozzi's method. Observation under a bright field microscopy revealed the presence of typical microorganisms with tennis racket appearance. Which of the following is the most likely diagnosis?

Correct Answer: A

Rationale: The correct answer is A: Botulism. Botulism is caused by the toxin produced by Clostridium botulinum bacteria found in improperly preserved or canned foods. The symptoms described align with botulism, such as difficulty swallowing and breathing due to muscle paralysis. The tennis racket appearance seen under microscopy corresponds to the characteristic appearance of Clostridium botulinum spores. The other choices can be ruled out based on the clinical presentation and microscopy findings. Cholera typically presents with severe watery diarrhea, Nontyphoidal Salmonella infection with fever and gastrointestinal symptoms, and Typhoid fever with high fever and abdominal pain. Therefore, the most likely diagnosis in this case is botulism.

Correct Answer: A

Rationale: Rationale: The correct answer is A: Trichomonas vaginalis. 1. Symptoms of urogenital inflammation match Trichomonas vaginalis infection. 2. Description matches Trichomonas vaginalis characteristics: pear-shaped, pointed spike, big nucleus, undulating membrane. 3. Trichomonas hominis and buccalis do not typically infect urogenital tracts. 4. Trypanosoma gambiense causes African trypanosomiasis, not urogenital infections.

Correct Answer: A

Rationale: The correct answer is A: BCG vaccination. The Mantoux test is used to detect tuberculosis infection. A negative reaction means the child is not infected. BCG vaccination is recommended for individuals without prior TB infection to prevent severe forms of the disease. Antitoxin and rabies vaccinations are not related to TB and are not indicated in this scenario. Repeating the Mantoux test is unnecessary since a negative result indicates absence of TB infection.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Filamentous spiral nucleocapsid is characteristic of Filoviridae, such as Ebola virus. 2. Linear unsegmented single strand (-) RNA is a key feature of Filoviridae genomes. 3. The lipid bilayer membrane of cellular origin is found in Filoviridae viruses. 4. Therefore, the correct answer is B (Filoviridae) due to the alignment of all three morphological features. Summary: - A (Picornaviridae): Has an icosahedral capsid, not filamentous spiral. - C (Orthomyxoviridae): Has a segmented genome, not linear unsegmented. - D (Togaviridae): Has a spherical capsid, not filamentous spiral.

Correct Answer: C

Rationale: Toxoplasma gondii is a protozoan parasite known to cause toxoplasmosis. It belongs to the group of eukaryotic organisms called protozoans because it is a single-celled organism with complex cellular structures. Protozoans are characterized by their ability to move and perform essential functions independently. Algae (choice A) are photosynthetic eukaryotic organisms, fungi (choice B) are non-photosynthetic eukaryotes that include molds and yeasts, and helminths (choice D) are multicellular parasitic worms. Therefore, the correct answer is C because Toxoplasma gondii is a protozoan parasite.