Sexually transmitted diseases

The correct option is Spirochete. Treponema pallidum is a thin, tightly coiled spirochete with endoflagella (axial filaments) that allow a corkscrew motion, enabling it to penetrate intact mucous membranes. Neisseria is a diplococcus.

The correct option is Secondary stage. The secondary stage of syphilis is characterized by systemic spread of the spirochetes, leading to widespread mucocutaneous rashes, classically involving the palms and soles, along with systemic symptoms like fever and lymphadenopathy.

The correct option is Herpes Simplex Virus type 2 (HSV-2). HSV-2 infects epithelial cells and then travels retrogradely up sensory nerve fibers to reside latently in the sacral ganglia. Stress or immunosuppression can trigger anterograde transport and recurrent painful blisters.

The correct option is Neonatal exposure to the virus during passage through the birth canal. Genital herpes is generally not transmitted across the placenta (unlike syphilis). Neonatal herpes is acquired via direct contact with infectious lesions in the birth canal, which a C-section bypasses.

The correct option is The HSV ulcer is preceded by painful fluid-filled vesicles. Genital herpes begins as painful vesicles (blisters) that rupture to form painful, shallow ulcers. The syphilitic chancre is a single, painless, firm (indurated) ulcer without a vesicular stage.

The correct option is CD4+ T-helper lymphocytes. HIV uses the CD4 receptor to enter and eventually destroy T-helper cells. The loss of these orchestrator cells severely impairs both humoral and cell-mediated immune responses, leading to AIDS.

The correct option is Neisseria gonorrhoeae. When a newborn passes through a birth canal infected with gonorrhea, the pathogen can infect the eyes, causing ophthalmia neonatorum. Routine prophylactic eye drops (e.g., erythromycin) are given to prevent this.

The correct option is Latent stage. Following the disappearance of secondary stage symptoms, syphilis enters a latent phase where the patient is asymptomatic but retains the spirochetes in tissues, maintaining positive blood tests for antibodies.

The correct option is Granulomatous lesions resulting from hypersensitivity reactions to remaining spirochetes. Gummas are soft, non-cancerous granulomatous growths that characterize tertiary syphilis. They are essentially a destructive delayed hypersensitivity immune response to localized persistent spirochete antigens.

The correct option is Dark-field microscopy. T. pallidum is too thin to be seen with standard bright-field microscopy and Gram stains poorly. Dark-field microscopy illuminates the live, motile spirochetes against a dark background, allowing immediate identification.

The correct option is Ectopic pregnancy. Scarring in the fallopian tubes restricts the passage of a fertilized ovum to the uterus, causing the embryo to implant within the tube (ectopic pregnancy), which is a life-threatening emergency.

The correct option is Antibiotics target bacterial cellular structures absent in viruses. Antibiotics (like penicillin) disrupt bacterial-specific processes like cell wall synthesis. Herpes is a virus, which lacks these structures and replicates inside host cells, rendering antibiotics completely ineffective.