Question

_____50. Most STIs are

                 A. bacterial                   B. viral                  C. fungal                    D. protozoan

_____51. Which one of the following venereal diseases is diagnosed by observing Gram

                 negative diplococci in the phagocytic leukocytes from a urogenital swab particularly

                 in men?

                 A. syphilis          B. gonorrhea           C. nonspecific urethritis          D. trichomoniasis

_____52. Which stage of syphilis is not infectious?

                 A. primary                 B. secondary                  C. tertiary                  D. chancroid

_____53. A distinctive symptom of secondary syphilis is

                 A. hard chancre with an exudative center               B. skin rash on the palms and soles     

                 C. gummatous lesion                                              D. paresis

_____54. The VDRL nontreponemal serological test involves all the following except

                 A. reagin-type antibody       B. cardiolipin       C. syphilis spirochete       D. blood

_____55. Ophthalmia neonatorum is caused by

                 A. Treponema pallidum                            B. Chlamydia trachomatis      

                 C. Acanthamoeba                                     D. Neisseria gonorrhoeae    

_____56. Which one of the following is most often associated with vaginosis?

                  A. Gardnerella vaginalis                         B. Candida albicans                    

                  C. E.coli                                                   D. herpes simplex virus

_____57. Which one of the following diseases kills the most people in the world each year?

                  A. tuberculosis             B. measles            C. hepatitis B           D. cholera             

_____58. Which one of the following organisms has never been cultured on bacterial media?

                 A. Mycobacterium tuberculosis                    B. Neisseria gonorrhoeae

                 C. Mycoplasma pneumoniae                          D. Treponema pallidum                        

_____59. Which one of the following statements about syphilis is true?

               A. the disease was probably introduced to the New World by Columbus’ crew

                 B. T. pallidum probably evolved from the organism that causes yaws

                 C. the causative organism has many virulence factors that enable it to invade

                 D. it is a disease that was originally described by Galen in ancient Greece

Answer 1

50) A. Bacterial

51) B. Gonorrhoea

52) C. Tertiary

53) B. Skin rash on palms and soles

54) C. Syphilis spirochete

55) B. Chlamydia trachomatis

56) A. Gardnerella vaginalis

57) A. Tuberculosis

58) D. Treponema pallidum

59) B. T. pallidum probably evolved from the organism that cause yawns.

Discussion and explanation :

50) Infections which are transmitted by sexual route are termed as sexually transmitted infections (STIs) or sexually transmitted diseases (STDs).

Commom STIs are - Chlamydia, Gonorrhoea, Bacterial vaginosis.These are all caused by bacteria.

Common viral STIs are - Herpes and human papilloma virus.

Common fungal STI - Candida

Common protozoal STI - Trichomonas

Incidence of syphilis has declined after introduction of penicillin.

51) Neiseria gonorrhoeae (gonoococci) are Gram negative intracellular diplococci causing STI termed as gonorrhoea.

Syphilis is caused by Treponema pallidum which is spirochete.

Non specific urethritis means urethritis caused by organisms other than Gonococcus, Chlamydia is common cause.

Trichomonas is protozoa.

52) and 53) Stages of syphilis :

A) Primary syphilis - After an incubation period ranging from 10-90 days a painless indurated chancre develops on genitalia.Infectious stage.

B) Secondary syphilis - Characterised by mucocutaneous lesion (macolopapular rashes on palms and soles) and generalised lymphadenopathy. Infectious stage.

C) Latent syphilis - Asymptomatic phase with positive serology. May be infectious in early latent phase.

D) Tertiary syphilis - Neurosyphilis characterised by meningitis and paralysis. Usually not infectious as compared to other stages.

54) Syphilis can be diagnosed by two types of tests:

A) Treponemal test - Specific for Treponema which recognise particular antigens/constituents.

B) Non- Treponemal tests - There are non specific test for Treponema.

RPR (Rapid plasma reagin) test and VDRL (Veneral disease research lab) test are two important non - Treponemal tests which detect nonspecific antibodies present in blood involving cardiolipin.

55) Ophtahalmia neonatorum also termed as neonatal conjunctivitis is usually acquired from mother's genital tract during delivery. Infectious causes are Chlamydia trachomatis (most common), Gonococcus and Staphylococcus.

56) Bacterial vaginosis is one of the common sexually transmitted infections caused by Gardeneralla vaginosis and is characterized by foul smelling discharge and itching.

57) Tuberculosis is one of the oldest and most widespread infectious disease spread worldwide. It is caused by Mycobacterium tuberculosis. Most of the cases and deaths due to tuberculosis occur in developing and underdeveloped countries.

Due to effective immunity provided by measles vaccine, currently measles is under control.

Cholera causes deaths due to sudden outbreak. Many cases are self limiting and require only rehydration and supportive therapy.

Hepatitis B runs a chronic course, may cause acute hepatitis and chronic liver disease.

58) Treponema pallidum cannot be cultured in vitro.

Mycobacterium tuberculosis can be cultured in LJ medium. Neisseia can be cultured on Thayer- Martin agar. Mycoplasma can be cultured on PPLO agar medium producing fried egg like colonies.

59) Syphilis was introduced into Europe (old world) from New world (America) by Columbus crew

Genetic studies have shown that all subspecies including Treponema pallidum pallidum (causing syphilis) are derived from Treponema pallidum pertenue (causing yaws)

Treponema pallidum has no well recognised virulence factors till now.