Transcript STI Surveillance for Public Health

Surveillance issues in STDs
• Public Health Perspectives on Women’s
Health
• Epidemiology of Hepatitis
• Evaluation of Partner Notification for
HIV
• Surveillance issues
• Contraception
Role of an Epidemiologist
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Surveillance
Evaluation
Hypothesis testing
Communicating Information
STD Control
• Two main function:
– To interrupt the transmission of infection
– To prevent the development of
complications and sequelae.
The importance of STI
surveillance for public health
Purposes of surveillance
• setting of priorities
• planning and allocating resources for service
• defining population subgroups and risky
behaviors for targeted interventions
• directing public health policy
• informing diagnostic and therapeutic practice
• evaluation of interventions
• stimulating further research
Surveillance Systems
• Are active or passive
• Can be for a whole population or
for a selected group (sentinel)
• Have to have a good case
definition
• Surveillance is better if it is
reportable
• Have to have quality assurance
Other STD
Surveillance
Other STDs
Sexually Transmitted Disease
Surveillance 1998
Division of STD Prevention
Herpes Simplex Virus 2
• In U.S. 50 million infections, 1million each year.
• Both HSV-1 and HSV-2 are acquired through
contact with infectious secretion on oral or genital
mucosal surfaces.
• HSV-1 acquired orally with latency in the
trigeminal nerve root. HSV-2 acquired genitally
with latency in the sacral root ganglia.
• Reactivation occurs throughout life and can be
either clinically symptomatic, symptomatic but
unrecognized as herpes, or subclinical.
• High prevalence related to chronicity of disease
and high frequency of unrecognized infection
Diagnosis of HSV-1
• Probably the most difficult STD to diagnose.
• Clinical spectrum is diverse. Clinical
diagnosis has reasonable specificity, but poor
sensitivity
• Viral isolation or demonstration of HSV
antigens in genital lesions has been the only
accurate lab diagnosis to confirm herpes and
it is only 50% sensitive.
• Serodiagnostics (i.e. PCR) are expensive
and are indirect and can be imprecise (also
pick up chancroid and syphilis)
Clinical differences in lesions
Genital herpes simplex virus type 2 Percent seroprevalence according to age
in NHANES* II (1976-1980) and NHANES
Percent
40
III (1988-1994)
32
24
16
NHANES II
NHANES III
8
0
12-19
20-29
30-39
40-49
Age Group
Note: Bars indicate 95% confidence intervals.
*National Health and Nutrition Examination Survey
50-59
60-69
70+
Human papillomavirus (genital warts) Initial visits to physicians' offices: United
States, 1966-1998 and the Healthy
Visits (in thousands)
People year 2000 objective
400
320
240
160
Genital warts
2000 Objective
80
0
1966
70
74
78
82
86
90
SOURCE: National Disease and Therapeutic Index (IMS America, Ltd.)
94
98
Nonspecific urethritis - Initial visits to
physicians' offices by men: United States,
1966-1998
Visits (in thousands)
400
320
240
160
80
0
1966
70
74
78
82
86
90
SOURCE: National Disease and Therapeutic Index (IMS America, Ltd.)
94
98
Trichomonal and other vaginal infections Initial visits to physicians' offices: United
States, 1966-1998
Visits (in thousands)
4,500
Trichomonal
Other Vaginitis
3,600
2,700
1,800
900
0
1966
70
74
78
82
86
90
SOURCE: National Disease and Therapeutic Index (IMS America, Ltd.)
94
98
Pelvic Inflammatory Disease
• Lower genital tract infections can lead to
endometrial and tubal infection and intern to
complications such as infertility, ectopic
pregnancy and chronic pelvic pain.
• Usually caused by Ct, but can be caused by
Gc.
• Symptoms vary. Chandelier sign is indicative
but doesn’t always occur. Best test is the
invasive laparoscopy.
• Scholes found in a randomized clinical trial
that selective testing for Ct prevented PID.
Bacterial versus Viral
• Bacterial usually treatable, viral usually
not
• After screening, bacterial usually
incidence, viral usually prevalence
• Screening generally easier for bacterial
and more difficult for viral
Contraception and Women’s
reproductive health
Contraception
• Important in STD research because it
causes behavior change
• It is associated with lesser incentive to
have protective sex
• May have some protective effect in
certain diseases.
Contraception
Prevalence of Contraceptive Methods in
US 1993
Method
Sterilization
Tubal ligation
Vasectomy
Oral Contraception
Condoms
Spermicide
Withdrawl
Periodic abstinence
Diapgraghm
Intrauterine Device
Implant
% Prevalence
27
15
12
25
19
6
6
3
2
1
1
Sterilization
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Tubal
Vasectomy
Hysterectomy
No STI protection
Return to fertility is possible
Norplant - implants
• levonorgestrel
• last 5 years
• prevents ovulation ,
causes luteal
insufficiency, impaired
oocyte maturation and
progestin-induced
hostile cervical mucus
• No STI prevention
• return to fertility is
rapid
Depo provera
• depot medroxyprogesterone acetate (DMPA) - The
Shot
• last 3-4 months
• can cause menstrual changes, irregular bleeding,
spotting, amenorrhea, headaches
• return to fertility can be one year
• No STI prevention
Post Coital Contraception
• Morning after pill - intended for
pregnancy prevention when women are
exposed to a single episode of
unprotected coitus
• Only Mifepristone (RU486) is FDA
approved
• prevent implantation
• No STI prevention
Oral Contraception
• Prevents ovulation by suppressing pituitary
gonadotropin secretion.
• Monophasic - constant dose of estrogen and
progestin in 21 active tablets
• Progestin-only oral low dose contraceptives
(mini-pills)
• Phasic alter progestin and estrogen.
• Associated with increased cervial chlamydia;
protective against symptomatic PID
Health Benefits of OCP
• Prevention of gynecologic cancer (epithelial
ovarian cancer and endometrial
adenocarcinoma)
• Menstrual improvements (regularity, less
dysmenorrhea, few days and amount of flow,
less anemia, restoration of regular menses in
anovulatory women)
• Prevention of benign conditions (breast
fibroadenoma, ectopic pregnancy)
• Possible benefits (atherosclerosis, severe
rheumatoid arthritis)
Intrauterine device
• copper intrauterine implant Copper T 380A IUD creates intrauterine environment that is spermicidal
• progesterone-releasing IUD (Progestasert) inhibit
sperm survival and implantation.
• PID can result if CT or GC are present
• No STI prevention
Natural Methods
• Periodic abstinence (calendar method,
temperature method, cervical mucus
method, symptothermal method)
• Lactational contraception
• Withdrawal
• None of these method provide STI
prevention
• Fertility return is rapid
Barrier Methods
• Latex Condom
• Diaphragms and
cervical caps
• spermicidal foams,
films, jellies or
suppositories
• Do protect against
STIs
Diaphragm and
Cervical Cap
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Diaphragm 80-94% effective
Cervical cap 60-90% effective
Not effective against STDs
can be messy
cost $13-$25, exam $150
only four sizes of cervical caps (hard to
fit all women)
Foams and
suppositories
Vaginal Contraceptive
Film
• Can't be felt by either partner
• Effective for up to one hour
• Nothing to remove Begins to dissolve
instantly
• Used by thousands of clinics
• Contains: 28% Nonoxynol 9, the spermicide
most recommended by doctors
• Numerous clinical studies conducted
worldwide on safety and efficacy
Emergency Contraception
• Yupee Method
• Take one dose within 72 hours and a second dose
12 hours after that
• If you are using Ovral, each dose is two pills. If you
are using Alesse, each dose is five pills. If you are
using any of the other combination pills listed above,
each dose is four pills.
• IUD can be inserted within 5 days of un-protected
intercourse.
• Reduced risk of unintended pregnancy be 75%
Male Methods
• Condoms
• Vasectomy
• Others