Lecture 5- sexually transmitted infections Flashcards
what is chlamydia?
Caused by Chlamydia trachomatis bacterium
Gram-negative intracellular bacteria
Transmitted easily through sexual contact
Asymptomatic infection common
Chlamydia infection can also occur in eyes and throat
Treated with either azithromycin or doxycycline (>95% cure)
what is syphilis?
Syphilis mainly spread throughclose contact with an infected sore - usually happens during sexual contact
Treated with antibiotics
what is congenital syphilis?
Transmitted in utero (across placenta)
Still birth, low birth weight, deformity
350,000 adverse pregnancy outcomes/year globally
Part of routine antibody ante-natal screen for infections in UK
Syphilis
HIV
HBV
what are viral STIs?
Most Common:
Human papillomavirus (HPV)
84.6% (53.6–95.0%) for women with 1 sexual partner
91.3% (69.5–97.7%) for men with 1 sexual partner
Herpes Simplex (HSV)
~ 3.7 billion persons (>50yrs) infected with HSV-1
~491 million persons (>50yts) infected with HSV-2
Hepatitis B Virus
296 million infected persons – 820,000 deaths per year
Human immunpdeficiency virus (HIV)
38.4 million infected persons – 650,000 deaths per year
Less Common:
Human T-lymphotropic virus type 1 (HTLV-1)
Molluscum contagiosum
Hepatitis A, C, and E viruses
Zika
Ebola
Mpox
what is genital herpes?
Genital herpes mainly caused by herpes simplex virus (HSV) type 2. Less commonly caused by HSV-1
Herpesviruses remain in the host lifelong following primary infection (latent state – HSV in neurons)
Can reactivate – symptomatic/asymptomatic
No cure. Can be treated with aciclovir to shorten an outbreak
how is HIV spread?
Contact with infected bodily fluids :Blood, Semen, Vaginal fluids, Breast milk
Most infections are acquired by sexual contact
Mother to child transmission (MTCT) significant without intervention (15-45%)
Significantly reduced when antiretroviral therapy is used in pregnancy
what are the antiretroviral therapies for HIV/AIDS
Use HIV-onhibitors from different classes to maximize outcome
Goal: reduce viral load to undetectable / or very low
Generally termed ART (antiretroviral therapy) or cART (combination ART)
Usually use 3 different drugs
Reverse Transcriptase Inhibitors
Protease Inhibitors
Entry Inhibitors
Integrase Inhibitors
how do you prevent HIV?
Pre-exposure prophylaxis (PrEP)
There are two pills approved for use as PrEP:
Truvada®is for people at risk through sex or injection drug use.
Descovy®is for people at risk through sex. Descovy is not for people assigned female at birth who are at risk for HIV through receptive vaginal sex.
what are genital warts?
Human papillomaviruses and genital warts
what is human papillomavirus (HPV)?
Circular double-stranded DNA of approximately 8Kb
More than 200 genotypes of HPV have been identified, including at least 40 that affect the genitals
Majority of HPV infections resolve spontaneously but can persist
Although self-limiting, symptoms can include anogenital warts, respiratory papillomatosis, and precancerous or cancerous cervical, penile, vulvar, vaginal, anal and oropharyngeal lesions
Grouped into high- or low-risk with almost all cervical cancers linked to the high-risk group
What is Gardasil 9?
Protects against:
HPV types 6 and 11 (90% genital warts)
HPV types 16 and 18, two high-risk HPVs that cause about 70% of cervical cancers
HPV types 31, 33, 45, 52, and 58,high-risk HPVsthat account for an additional 10% to 20% of cervical cancers
The trials that led to approval of Gardasil 9 found it to be nearly 100% effective in preventing cervical, vulvar, and vaginal infections and precancers caused by all seven cancer-causing HPV types (16, 18, 31, 33, 45, 52, and 58)
what vaccines are available?
Vaccines are one of the most effective measure to reduce the burden of viral infections
Approved vaccines are available against:
HPV
HBV
Ebola
Mpox
Molluscum contagiosum?
what does the HPV death cycle lead to?
cancer
new HIV diagnosis, AIDS at diagnosis and all-cause deaths in people with HIV in the UK from 2001 and 2020
In 2020, the total number of people newly diagnosed with HIV continued to decrease to 2,776 from a peak in 2005 (7,959).
Reports of AIDS and all-cause deaths among people with HIV have remained low since the introduction of effective antiretroviral therapy in the mid-1990s.
Data reported in 2020 is impacted by the changes in how people accessed health services and reconfiguration of health services during the national response to COVID-19 and data reporting delays and data from Scotland in 2020 is unavailable.
