STD Diseases (PDF)

Sexually transmitted diseases(STD)/Venereal diseases  An infection transmitted through sexual contact. Caused by bacteria, viruses or parasites. Infections of the reproductive system are mainly classified in to NON SPECIFIC: It is usually caused by a range of microbes. Eg: Staphylococc...

Sexually transmitted diseases(STD)/Venereal diseases  An infection transmitted through sexual contact. Caused by bacteria, viruses or parasites. Infections of the reproductive system are mainly classified in to NON SPECIFIC: It is usually caused by a range of microbes. Eg: Staphylococci, Streptococci, Coliform bacteria SPECIFIC : It is caused by sexually transmitted microbes, The most common diseases are Bacterial vaginosis, Chancroid,Gonorrhea,Lymphogranuloma venereum(LGV).Nongonococcal Urethritis, Syphilis etc.  The microbes that causes STD’s are:- Unable to survive outside the body for longer periods. No intermediate hosts Produces lesions in the genital area which discharges the infecting microbes Requires intimate contact for its transmission Very sensitive to environmental stresses  Common symptoms Unusual discharge from the penis or vagina Warts or lesions on the genital area Burning while urinating Anal itching, redness, soreness and sometimes bleeding Neisseria gonorrhoeae  A gram negative, coffee-bean shaped bacterium Grow on Chocolate Agar. The second most common disease in US Gonorrhea [Greek gono, seed, and rhein, to flow] is an acute, in- fectious, sexually transmitted disease of the mucous membranes of the genitourinary tract, eye, rectum, and throat. It is caused by gram-negative, oxidase-positive, diplococcus- Neisseria gonorrhoeae. These bacteria are also referred to as gono- cocci [pl. of gonococcus; Greek gono, seed, and coccus, berry) and have a worldwide distribution  Gonococci attach to the microvilli of mucosal cells by means of pili and protein II. This attachment prevents the bacteria from being washed away by normal cervical and vaginal discharges or by the flow of urine. Gonococci are then phagocytosed by the mucosal cells and may even be transported through the cells to the intercellular spaces and sub-epithelial tissue The host's defenses have little effect on the bacteria. Following penetration of the bacteria, the host tissue responds locally by the infiltration of mast cells.  Symptoms In males the incubation period is 2 to 8 days. The onset consists of a urethral discharge of yellow, creamy pus, and frequent, painful urination that is accompanied by a burning sensation. In females, the cervix is the principal site infected. some symptoms may begin 7 to 21 days after infection. some vaginal discharge may occur. The gonococci also can infect the Fallopian tubes and surrounding tissues, leading to pelvic inflammatory disease (PID). This occurs in 10 to 20% of infected females. Gonococcal PID is a major cause of sterility and ectopic pregnancies because of scar formation in the Fallopian tubes. -------------  Gonococci disseminate most often during menstruation. This time there is an increased concentration of free iron available to the bacteria. In both genders, disseminated gonococcal infection with bacteremia may occur. This can lead to involvement of the joints (gonorrheal arthritis), heart (gonorrheal endocarditis), or pharynx (gonorrheal pharyngitis). Gonorrheal eye infections can occur in newborns as they pass through an infected birth canal. The resulting disease is called ophthalmia neonatorum, or conjunctivitis of the newborn. This was once a leading cause of blindness in many parts of the world. To prevent this disease, tetracycline, erythromycin, povidone-iodine, or silver nitrate in dilute solution is placed in the eyes of newborns.  The gonococci are very sensitive to adverse environmental conditions and survive poorly outside the body. Specimens should be plated directly. The Centers for Disease Control and Prevention recommends as treatment five single doses of cefixime, cefriaxone, ciprofloxacin, ofloxacin, and levofloxacin to eradicate the infection. Penicillin-resistant strains of gonococci occur worldwide. Most of these strains carry a plasmid that directs the formation of penicillinase, a ß-lactamase enzyme that inactivates penicillin G and ampicillin.  The most effective method for control of this sexually transmitted disease is public education. Diagnosing and treating the asymptomatic patient, barrier protection, and treating infected individuals quickly to prevent further spread of the disease. More than 60% of all cases occur in the 15- to 24-year-old age group. Repeated gonococcal infections are common. Protective immunity to reinfection does not arise because of antigenic variation in which a single strain changes its pilin gene by a recombinational event and alters the expression of the various protein II genes. Lymphogranuloma Venereum (LGV)  It is a sexually transmitted disease caused by Chlamydia trachomatis serotypes L1-L3. It has a worldwide distribution It is more common in tropical climates. LGV proceeds through three phases:- (1) In the primary phase- small ulcer appears several days to several weeks after a person is exposed to the chlamydiae. The ulcer may appear on the penis in males or on the labia or vagina in females. The ulcer heals quickly and leaves no scar. (2) The secondary phase begins- 2 to 6 weeks after exposure. The chlamydiae infect lymphoid cells, causing the regional lymph nodes to become enlarged and tender, such nodes are called buboes Systemic symptoms such as fever, chills, and anorexia are common.  (3) If the disease is not treated, a late phase ensues. This results from fibrotic changes and abnormal lymphatic drainage that produces and urethral or rectal strictures (a decrease in size). An untreatable fluid accumulation in the penis, scrotum, or vaginal area may result Phylum Chlamydiae  The disease is detected by staining infected cells with iodine to observe inclusions culture of the chlamydiae from a bubo, nucleic acid probes, or by the detection of a high antibody titer to C. trachomatis. Treatment in the early phases consists of aspiration of the buboes and administration of the drugs azithromycin, ceftriaxone, erythromycin, or ciprofloxacin. The late phase may require surgery. The methods used for the control of LGV are the same as for other sexually transmitted diseases: abstinence, barrier protection, and early diagnosis and treatment of infected individuals. Nongonococcal Urethritis  Nongonococcal urethritis (NGU) is any inflammation of the urethra not due to the bacterium Neisseria gonorrhoeae. This condition is caused both by non-microbial factors such as catheters and drugs and by infectious microorganisms. The most important causative agents are C. trachomatis, Ure- aplasma urealyticum, Mycoplasma hominis, Trichomonas vaginalis, Candida albicans, and herpes simplex viruses. Most infections are acquired sexually  Symptoms of NGU: Males may have few or no manifestations of disease; however, complications can exist. These include a urethral discharge, itching, and inflammation of the male reproductive structures. Females may be asymptomatic or have a severe infection leading to PID, which often leads to sterility. In the pregnant female, a chlamydial infection is especially serious, because it is directly related to miscarriage, stillbirth, inclusion conjunctivitis, and infant pneumonia.  Diagnosis of NGU requires the demonstration of a leukocyte exudate and exclusion of urethral gonorrhea by Gram stain and culture. Syphilis  Venereal syphilis is a contagious, sexually transmitted disease caused by the spirochete Treponema pallidum sub sp. Pallidum Congenital syphilis is the disease acquired in utero from the mother. T. pallidum enters the body through mucous membranes or minor breaks or abrasions of the skin. It migrates to the regional lymph nodes and rapidly spreads throughout the body.  Three recognizable stages of syphilis:- In the primary stage, after an incubation period of about 10 days to 3 weeks or more. The initial symptom is a small, painless, reddened ulcer, or chancre with a hard ridge that appears at the infection site and contains spirochetes. Contact with the chancre during sexual contact may result in disease transmission. In about one-third of the cases, the disease does not progress further and the chancre disappears. Serological tests are positive in about 80% of the individuals during this stage. The spirochetes typically enter the bloodstream and are distributed throughout the body.  Secondary stage is characterized by a highly variable skin rash. By this time 100% of the individuals are serologically positive. Other symptoms during this stage include the loss of hair patches, malaise, and fever. Both the chancre and the rash lesions are infectious.  During the latent period the disease is not normally infectious, except for possible transmission from mother to fetus (congenital syphilis). After many years a tertiary stage develops in about 40% of untreated individuals with secondary syphilis. During this stage de-generative lesions called gummas form in the skin, bone, and nervous system as the result of hypersensitivity reactions.  This stage also is characterized by a great reduction in the number of spirochetes in the body. Involvement of the central nervous system may result in tissue loss that can lead to cognitive deficits, blindness, a "shuffle"walk (tabes), or insanity. Diagnosis of syphilis: is through a clinical history, physical examination, and dark-field and immunofluorescence examination of lesion fluids for typical motile spirochetes. Humans respond to T. pallidum with the formation of anti-treponemal antibody and a complement-fixing reagin. serological tests are very informative.  Prevention and control of syphilis : (1) public education (2) prompt and adequate treatment of all new cases, (3) follow-up on sources of infection and contact so they can be treated, and (4) prophylaxis (barrier protection) to prevent exposure. At present, the incidence of syphilis, as well as other sexually transmitted diseases, is rising in most parts of the world. The highest incidence is among those 20 to 39 years of age.  Treatment in the early stages of the disease is easily accomplished with long-acting benzathine penicillin G or aqueous pro- caine penicillin. Later stages of syphilis are more difficult to treat with drugs and require much larger doses over a longer period. For example, in neuro syphilis cases, treponemes occasionally survive such drug treatment. Immunity to syphilis is not complete, and subsequent infections can occur  The causative agent is Haemophilus ducreyi. Bacterium enters the skin through a break in the epithelium. Incubation period is 4-7 days. Occurs most frequently in the tropical areas. It is difficult to diagnose, so it is under reported Very common in Asia, Africa and in Latin America  SYMPTOMS A swollen, painful ulcer on genitals – infection on the lymph nodes Infected lymph nodes – breaks – discharges pus to the surface Lesions – serve as an important factor in the transmission of HIV Lesions might also occur in tongue and lips. Diagnosis by isolating bacteria from ulcers. Treatment with Azithromycin or Ceftriaxone Trichomonas vaginalis Trichomoniasis  This protozoan is a normal inhabitant of the vagina in females and that of urethra in males It is usually sexually transmitted If the normal acidity of the vagina is disturbed, the protozoan may overgrow the normal microbial population of the genital area and causes TRICHOMONIASIS In response to the infection, the body accumulates leukocytes at the site of infection.  The resulting discharge is profuse, greenish yellow and it is characterized by a foul odour The discharge is often accompanied by itching and irritation Not a reportable case Considered relatively benign It causes preterm delivery and problems associated with this is low birth weight.  Diagnosis: Microscopic Examination of the discharge Isolating the pathogen from semen or urine of male carriers and grown on laboratory medias RAPID TESTS – DNA PROBES & MONOCLONAL ANTIBODIES Treatment – oral metronidazole, - administered to both the sex partners, - readily clears the sort of infection