1. Assistant Professor Khalis Bilal College of medicin
Sexually Transmitted
Infections
1st lecture
Assistant Professor Khalis Bilal College of medicin
HMU

2. Objectives:
At the end of the lecture the student should be familial with:
Definition of STI
Epidemiology of STIs
Factors contribute in transmission of STIs

3. Definition:
Sexually transmitted infections (STIs) are infections that are spread primarily through person-to person sexual contact.
They are not restricted only to the genital tract, but many of them were found to be of systemic nature.

4. History
Venereal diseases
STDs
STIs

5. Transmission occurs through:
:1. Sexual contact
Heterosexual, MSM, oral sex.
2. Non-sexual transmission (some):
a. Vertical (Transplacental)
b. Exposure to blood and blood products.
c. Organ transplantation.
d. Exposure to contaminated syringe and medical instruments, tissues.
e. Razors, tooth brush.
f. Autoinfection.

6. Epidemiology: Generally maximum prevalence is in developing countries.
There is marked variation in the prevalence and incidence of infections throughout the world, and even within countries.
Generally maximum prevalence is in developing countries.

7. Globally, up to 10% of reproductive age adults are infected with one STI each year.
It is estimated that about 12 million U.S. residents develop a new STI each year.
At least 50% of all people in the U.S. will develop an STI at some time before they are 35 years old.
About 3 million teenagers contract an STD each year.
CDC estimates that 19 million new infections occur annually in the United States, almost one half of which occur in persons 15 to 24 years of age.

8. Who gets STI.
Most common age groups are yrs.
In the USA, up to 1 in 4 adolescent females have an STI.
In the UK, 16- to 24-year olds are the age group most at risk of being diagnosed with one of STIs, accounting for 65% of all chlamydial infections, 55% of genital warts, and 52% of gonorrhoea.

9. Clinical distribution of lesions:
Lesions are generally present on the genitalia, and the infective agents are there, also present in the secretions and discharges from the urethra and the vagina and in the blood.
Extra genital lesions may occur through haematogenic dissemination as in syphilis or through inoculation of the infective agent at extra genital sites.

10. Factors contribute in spread of STIs:
Sexual Promiscuity

11. The transmission of STI almost always implies sexual activity involving at least three persons.
For if A infects B, it implies that A has also had sexual contact with at least one other person X, who infected A.

12. Social factors
Prostitution : This is a major factor in the spread of STDs. The prostitute acts as a reservoir of infection.
In Asia, most STDs are contracted from prostitutes.
Easy money: In most of the developing world, prostitution is simply a reflection of poverty. It provides an occupation for earning easy money. It is fostered by lack of female employment and the prospect of a financial return impossible to achieve by other means

13. Demographic factor
Population explosion and marked increase in the number of young people, the group at highest risk for STI in the population.
The migration of youth from rural to industrial urban areas in search of works along with overcrowding, loneliness and anonymity.

14. Family planning
Various measures are adopted to control birth rate, e.g. the condoms, IUCD, and contraceptive pills have removed the fear of pregnancy, and caused greater freedom for both men and women.
Hence, F.P. is contributing in its own way to increase in STIs.

16. Population movement
Persons engaged in occupations involving frequent travel are the high risk group.
Examples:
Sailors, truck drivers, sale representatives, tourism and during long lasting wars and conflicts.

17. STI and travel
International travel contributes to the global spread of STIs and resistant strains of infections.
›› High-risk groups of travelers include:
truckers, seamen, sex tourists, and long-term visitors.
›› A feeling of sexual freedom and lack of social constraints often contribute to casual sex encounters.
›› Use of alcohol and other drugs is associated with decreased condom usage and leads to increased rates of STIs during travel.
›› The physician must consider a patient’s travel history as this may indicate that the patient has a strain of infection that may have a different susceptibility profile.

18. Easy and inadequate treatment
A paradoxical reason for increase in STDs is extreme simplicity and easy availability of treatment.
The one shot penicillin therapy of gonorrhea and syphilis has reduced the fear of the disease, and consequently increased the sexual contact, under inadequate antibiotic cover.
Consequently; emergence of antibiotic-resistant organisms- a feature frequently observed in response to inadequate and haphazard treatment.

19. Lack of control measures
In many developing countries, the governmental (official) facilities for the diagnosis, contact tracing, follow up and health education are very poor.

20. Other factors contribute to the spread of STDs:
Unprotected sex
Immune compromised persons
Child abuse
Premarital sexual relationships
Prison inmates
No circumcision

21. Factors contribute to the spread of STDs: (cont.)
Low SE status
Poor hygiene
Lack of treatment and chronicity of the disease
Poverty, war, and lack of access to medical care or medicines.
Drug abuse and alcoholism.
Availability of drugs for erectile dysfunction.

22. All these factors have been responsible for the so called -sexual revolution- which has sparked off the worldwide increase in STIs.

24. References:
1. Gerd Goss. Sexually transmitted infections and sexually transmitted diseases. Springer publications London 2011.
2. Park K. Textbook of Preventive & Social Medicine. 16th edition. Banarsidas Bhanot India 2008.
3. ABCs of STIs. Karen E Rogstad, 6th edition, Wiley-Blackwell, BMJ books, 2011.
4. Thomas Habif. Clinical dermatology, 6th edition 2016.