Epidemiology and Control of special groups of communicable diseases

1. Epidemiology and Control of special groups of communicable diseases Dr. Igbinedion MBBS, MPH, FRSPH, ACIEH

2. AKA Sexually transmitted infections- The preferred term used nowadays because someone can have the infection without having the disease. • AKA Venereal diseases • These are diseases primarily transmitted through sexual intercourse. This is not always the case • Infections are gotten through vaginal intercourse, oral sex, anal sex, IV drug use, breast feeding and delivery Sexually Transmitted Diseases

3. Classification of STDs • Bacterial • Gonorrhea (Neisseria gonorrhoeae) • Syphilis (Treponemapallidum) • Chlamydia (Chlamydia trachomatis) • Chancroid (Haemophilusducreyi) • Granuloma inguinale (Campylobacter granulomatis) Sexually Transmitted Diseases (contd.)

4. Viral • Viral hepatitis (Hepatitis B) • HIV/AIDS • Herpes simplex I & II • Human Papilloma virus (HPV)- genital warts • Molluscumcontagiosum • Fungal • Candidiasis Sexually Transmitted Diseases (contd.)

5. Parasites • Scabies (Sarcoptesscabiei) • Crab louse (Pthirus pubis)- aka pubic lice or crabs • Protozoal • Trichomoniasis (Trichomonasvaginalis) Sexually Transmitted Diseases (contd.)

6. Prevalence of STI’s among sexually active adolescents include • Chlamydia (10-25%)-girls (9-11%)-boys • Gonorrhea (3-18%)-girls (2-3%)-boys • Syphilis (0-3%) • Trichomonas (8-16%) • Herpes simplex (2-12%) Sexually Transmitted Diseases (contd.)

7. Determinants of STI’s • Age- highest between 20-24 years (15-19; 25-29) • Sex- clinical manifestation is higher in males because they present with symptoms more than females. Also, promiscuity level in men • Sexual preference- more infections in homosexual men (gonorrhea, syphilis, etc) than women (candidiasis) • Race- higher among blacks Sexually Transmitted Diseases (contd.)

8. Socioeconomic factors- STI’s higher in those of lower status • Environmental factors- more in urban than rural areas • Occupation- commercial sex workers, off shore workers, long distance drivers • Use of antibiotics and antifungals, which can be bought over the counter can reduce prevalence of STI’s. It can also increase resistant strains, thereby increasing incidence of disease Sexually Transmitted Diseases (contd.)

9. Control of STI’s • Health education • Promoting condoms- through sexual health clinics, etc • Vaccines • Screening • Early diagnosis and treatment • Contact tracing • Case findings • Rehabilitation- psychosocial; economic- provide alternative source of income for commercial sex workers Sexually Transmitted Diseases (contd.)

10. C. trachomatis is only found in humans • Causes genital and eye disease- Trachoma and inclusion conjuctivitis (TRIC)- most common cause of blindness worldwide • Transmission is through vaginal, anal or oral sex and childbirth • Causes permanent reproductive damage if left untreated Chlamydia

11. Distribution • One of the most common STI worldwide- it is estimated that 1:15 sexually active females between ages 14-19 have chlamydia • Most common STI in the USA- estimated 2.8 million cases yearly • Most common bacterial STI in the UK • Globally, about 215 million people were estimated to be affected as at 2010 Chlamydia

12. Determinants • Age- more common in younger children • Hygiene • Overcrowding • Immunity • Other infections worsen prognosis Chlamydia

13. Clinical features • Asymptomatic- aka silent infection • Vaginal discharge • Burning sensation while urinating • Pelvic inflammatory disease • Infertility • In men- epididymitis (pain and swelling in testicles) • Untreated chlamydia increases chances of developing HIV Chlamydia

14. Diagnosis • Polymerase chain reaction • Vaginal swab • Urine • Treatment • Antibiotics- azithromycin, doxycycline, erythromycin • Abstain from sex during treatment till about 7 days after Chlamydia

15. According to WHO, in 2011, about 34 million people were living with HIV • More in sub Saharan Africa with 1 in 20 adults living with HIV • There is no cure • Target to provide anti retroviral therapy to 15 million people by 2015. In 2011, more than 8 million people in low and middle income countries were receiving ARTs HIV/AIDS

16. Classification • HIV 1- global distribution; high virulence and infectivity • HIV 2- found in West Africa; low virulence and infectivity • Transmission • Sexual intercourse- semen, pre ejaculate, vaginal secretions • Cuts • IV drug use • Blood transfusion • Organ transplant • Mother to child transmission- transplacental and breast milk HIV/AIDS

17. Clinical features • Depends on stage of infection • There are 3 stages • Initial- mononucleosis type infection, seroconversion • Intermediate- AIDS related complex- fever, weight loss and persistent lymphadenopathy • Late- full blown AIDS with opportunistic infections e.g. Tb HIV/AIDS

18. Diagnosis • Detecting HIV antibodies in the blood • ELISA • Western blot- confirmatory • There is a window period of 3-6 weeks where antibodies are produced but not yet detectable. This is the time of greatest infectivity HIV/AIDS

19. Prevention and Control • Voluntary counseling and testing for HIV and STIs • Use of male and female condoms • Voluntary medical male circumcision • ART • IV drug users- IV drug programs, etc. • Preventing MTCT HIV/AIDS

20. HIV programs in Nigeria • Nigeria HIV/AIDS program development project- World Bank • Integrated MSM (men who have sex with men) HIV prevention program- USAID funded • U.S. Department of Defense HIV program (Nigeria) • AIDS Prevention Initiative in Nigeria (APIN) HIV/AIDS

21. http://en.wikipedia.org/wiki/Sexually_transmitted_disease • http://en.wikipedia.org/wiki/Chlamydia_infection • http://www.cdc.gov/std/chlamydia/STDFact-Chlamydia.htm • http://en.wikipedia.org/wiki/HIV • http://www.who.int/mediacentre/factsheets/fs360/en/index.html References