Researchers of a bacteriological laboratory examine tinned meat for botulinic toxin. For this purpose a group of mice was injected with an extract of the material under examination and antitoxic antibotulinic serum of A, B, E types. A control group of mice was injected with the same extract but without antibotulinic serum. What serological reaction was applied?

Correct Answer: A

Rationale: The correct answer is A: Neutralization. In this experiment, the researchers used antitoxic antibotulinic serum of different types to neutralize the botulinic toxin in tinned meat extract injected into mice. Neutralization is the process of rendering a toxin harmless by combining it with specific antibodies. The purpose of injecting the antitoxic serum was to neutralize the toxin and prevent it from causing harm to the mice. This serological reaction of neutralization directly aligns with the objective of the experiment. Summary of other choices: B: Precipitation - Precipitation involves the formation of a visible insoluble complex when an antigen reacts with its corresponding antibody. This process was not described in the scenario. C: Complement binding - Complement binding involves the activation of the complement system by antigen-antibody complexes. This was not the main focus of the experiment described. D: Double immune diffusion - This technique is used to detect the presence of specific antigens or antibodies

Correct Answer: A

Rationale: The most likely diagnosis is A: Leptospirosis. Leptospirosis is caused by the spirochete Leptospira interrogans and is commonly transmitted through contact with water contaminated by animal urine, such as in this case of fishing. The symptoms described match those of leptospirosis, including high fever, headache, muscle pain, jaundice, hemorrhagic rash, and bloody urine. The calf muscle pain is a characteristic symptom of leptospirosis known as "Weil's disease." Yersiniosis (B) typically presents with abdominal symptoms, Salmonellosis (C) with gastrointestinal symptoms, and Brucellosis (D) with flu-like symptoms. Therefore, based on the symptoms and history provided, Leptospirosis is the most likely diagnosis.

Correct Answer: A

Rationale: The correct answer is A: Metronidazole. Metronidazole is the drug of choice for amebic dysentery as it effectively targets the protozoa causing the infection. It has good tissue penetration and high efficacy against Entamoeba histolytica. Pyrantel (B) is used for nematode infections, not amebiasis. Levamisole (C) is an anthelmintic for roundworms and not effective against amoebas. Bicillin-5 (D) is a penicillin antibiotic, which is not indicated for treating amebic dysentery.

Correct Answer: A

Rationale: The correct answer is A: Trichomonas vaginalis. Trichomonas vaginalis is a flagellated protozoan parasite commonly found in vaginal infections. The presence of flagellated bacteria in the vaginal discharge stained with Romanovsky-Giemsa method indicates a protozoan infection, ruling out bacterial or viral causes. Choices B, C, and D are not correct as Leishmania donovani causes leishmaniasis, Trypanosoma gambiense causes African sleeping sickness, and Trihomonas hominis is a non-pathogenic flagellate found in the human intestine, not typically associated with vaginal infections.

Correct Answer: A

Rationale: The correct answer is A: Toxoplasma. Toxoplasma gondii causes Toxoplasmosis, a protozoan disease that can affect the brain and lead to vision loss. The halfmoon-shaped unicellular organisms with pointed ends described in the blood analysis are characteristic of Toxoplasma parasites. Toxoplasma infection commonly occurs through ingestion of contaminated food or water, or contact with infected cat feces. Leishmania causes Leishmaniasis, Lamblia causes Giardiasis, Amoeba causes Amebiasis, and Trichomonad causes Trichomoniasis, none of which match the symptoms and blood analysis findings described in the question.