Free Sexually Transmitted Diseases MCQs with Answers

1. Gonorrhoea is caused by

• A. a bacterium
• B. a virus
• C. a fungus
• D. a protozoan

Explanation: Neisseria gonorrhoeae is a diplococcus bacterium that infects the mucous membranes of the urinary and reproductive tracts, and because it is bacterial the infection can be cured with the right antibiotic. Untreated it can spread to the fallopian tubes and cause sterility, and it can infect the eyes of a baby during birth. Antibiotic resistant strains are now common, so self medication is dangerous.

2. Which sexually transmitted disease is caused by a spirochaete and passes through primary, secondary and tertiary stages?

• A. Gonorrhoea
• B. Syphilis
• C. Genital herpes
• D. Candidiasis

Explanation: Syphilis is caused by the spiral bacterium Treponema pallidum, beginning as a painless ulcer, then a body wide rash, then a long latent period, and finally damage to the heart, blood vessels and nervous system years later. This staged course is unique among the common sexually transmitted infections. Gonorrhoea is also bacterial but does not follow this pattern, and herpes and candidiasis are viral and fungal respectively.

3. Which sexually transmitted disease cannot be cured by antibiotics?

• A. Gonorrhoea
• B. Syphilis
• C. Chlamydia
• D. Genital herpes

Explanation: Genital herpes is caused by herpes simplex virus, and antibiotics act only on bacterial structures and pathways, so they are useless against it. Antiviral drugs can shorten and space out the attacks but the virus stays latent in nerve ganglia for life. The other three are bacterial infections and are curable if treatment is started early and completed.

4. The most effective way to prevent sexually transmitted infections is

• A. taking an antibiotic after every possible exposure
• B. vaccination, since a vaccine exists for every such infection
• C. washing thoroughly after exposure
• D. avoiding contact with infected persons and using barrier protection

Explanation: Prevention works by stopping the exchange of infected body fluids, so avoiding contact with an infected person and using a barrier are what actually reduce risk, together with screened blood and sterile needles. Taking antibiotics after exposure treats nothing viral and encourages resistance. Vaccines exist for hepatitis B and human papillomavirus but not for gonorrhoea, syphilis, herpes or HIV.

5. The bacterium Treponema pallidum is responsible for which sexually transmitted disease?

• A. Syphilis
• B. Chlamydia
• C. Gonorrhea
• D. Genital herpes

Explanation: Treponema pallidum is the spiral bacterium, or spirochaete, that causes syphilis, a disease progressing through primary, secondary, latent and tertiary stages over many years if untreated. Gonorrhoea is caused by the diplococcus Neisseria gonorrhoeae and chlamydia by Chlamydia trachomatis. Genital herpes is viral and therefore not treatable with antibiotics at all.