Topic 9 – Flashcard
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Sexually transmitted infection (STI)
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-infections transmitted from one person to another during coitus or other genital contact - in the past were referred to as venereal disease, after venus goddess of love -organisms causing STIs usually require moist membranes of transition zones
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Percentage of americans with STI
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25% of americans between ages 15 and 55 will acquire some form of STI -over 15 million americans in USA acquire an STI every year
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Transition zones
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occur at the openings between external and internal body surfaces Female: vulva, vagina, urethra Male: penis, and urethra both: mouth oral cavity, throat, eyes, and anus
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vaginal enviornment
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-under influence of estrogen, cells of the vaginal epithelium accumulate large amounts of glycogen -at these glycogen rich cells slough off into vaginal cavity, commensal bacteria metabolize glycogen to lactic acid which makes vaginal environment acidic - acidic environment retards Canadia yeast fungal overgrowth - certain antibiotics kill these beneficial bacteria which results in the vaginal environment becoming basic which supports development of Candida yeast vaginitis infections
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groups of STI
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-viral -bacterial -fungal -protozoan -lice -scabies
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incidence vs prevalence
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incidence is new cases/year prevalence is number of new and existing cases present at a certain time
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USA annual incidence of STI high to low
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HPV, chlamydia, trichomoniasis, gonorrhea, genital herpes , syphilis , HIV, Hep B
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USA annual prevalence of STI high to low
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HPV, genital herpes simplex, trichomoniasis, chlamydia, HIV, hep B, gonorrhea, syphilis
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global annual incidence of STI
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HPV, trichomoniasis , chlamydia, gonorrhea, genital herpes simplex, syphilis, hep B, HIV
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global annual prevalence of STI
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genital herpes simplex, HPV, Hep B, trichomoniasis, chlamydia, HIV, gonorrhea, syphilis
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Viral STIs
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-human papilloma virus( genital warts) - herpes simplex virus type 2 (herpes genitalis) -human immunodeficiency (HIV) -hepatitis B virus -hepatitis C virus -Molluscum contagiosum
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Bacterial STIs
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-chlamydia trachomatis -neisseria gonorrhoeae -Treponema Pallidum (syphilis) -Ureaplasma urealyticum (urethritis) -Haemophilus ducreyi (chancroid) -Haemophilus vaginalis (vaginitis and urethritis) -Calymmatobacterium granulomatous (granuloma inguinale)
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STI fungal
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Candidal albicans
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Protozoan
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trichomonas vaginalis (vaginitis)
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Crab lice
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Phthirus pubis, crab louse that attach onto genital hairs and live on blood
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Scabies
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-Sarcoptes scabiei, burrow under the skin and are transmitted by skin to skin contact
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Trichomonas vaginalis
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-flagellate protozoan transmitted during coitus -vaginitis with frothy odorous discharge that develops 4-28 days post exposure -vulva, cervix urethra and bladder may also become inflamed -most men are asymtopmatic but amy develop urethritis or cystitis - treatment with single dose of Metronidazole
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Chlamydia
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small bacteria transmitted by coitus - incubation period is 7-28 days -50% of infected men are asymptomatic - nearly half of chlamydia cases in women in USA occur in adolescents age 15-19 -can cause urethritis in both men and women resulting in yellow discharge from urethra
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chlamydia transmission
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can be transmitted to eyes of a newborn in vaginal canal during delivery - the infection can lead to conjunctivitis and pneumonia in the newborn infant - newborn's eyes are routinely treated with topical antibiotics
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chlamydia in women
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-cervix is main site of infection in females which can cause yellow vaginal dicharge -the cervix vagina, urethra and vulva can become reddened and irritated -scarring and blockage of the oviducts which can cause infertility -PID can also occur in women
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salpingitis
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oviduct inflammation
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Chlamydia diagnosis
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Diagnosed with urine (first stream) collected and PCR evaluation detects genetic material from chlamydia or culture of purulent material
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chlamydia treatment
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-Azithromycin by mouth - doxycyclin by mouth
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Gonorrhea
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-Nisseria gonorrhea is gram negative diplococcus bacteria that causes STI - Transmitted during homosexual and heterosexual coitus -bacteria thrive in moist membranes of the urogenital tract, mouth oral cavity, anus and eyes -most new cases are in 15-29yr old age group
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gonorrhea incidence is high in two groups
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1) sexually active individuals under age 24 2) men who have sex with men
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Gonorrhea in Men
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70-90% of men infected develop symptoms: -purulent discharge from urethra, rednesss of glands and penis, urethritis, prostatitis, epididymitis, orchitis (testes inflammation)
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Gonorrhea in women
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-75% are asymptomatic - Symptomatic females develop whitish yellowish or greenish discharge from: vagina, cervix, urethra, bladder
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gonorrhea complications in females
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-endometriosis: uterine infection - salpingitis: inflammation and infection of oviducts which can cause scarring of tissue leading to infertility because of oviduct blockage -Pelvic inflammatory disease: general infection of pelvic tissue
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Oral sex
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oral sex can lead to infection of pharynx (throat) with gonococcus
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gonorrhea in pregnancy
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-if transmitted across placenta to fetus in the first trimester there is an increased risk of miscarriage - when present in the birth canal can infect newborns eyes on delivery -newborns' eyes are routinely treated with topical antibiotics
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Gonorrhea diagnosis
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-urine (first stream)is collected and PCR evaluation detects genetic material from gonococcus -culture of purulent material -swab of throat
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Gonorrhea treatment
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ceftriaxone injectione doxycycline by mouth
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Syphilis bacteria
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-Treponema palladium spirocete bacterium - thrives in moist regions of body -90% of syphilis is transmitted by sex, but can also be transmitted into an open sore on skin
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Syphilis in USA
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-number of syphilis cases in USA population has increased each year between 1999-2006 -in 2006 60% of new cases were in gay men - in 1988 5% of new cases were in gay men
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Syphilis Primary stage
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-chancre sore develops at site where syphilis entered the body, appear 10-90 days after entrance of microbe and last for 1-5 weeks person is contagious during this stage -these painless chancres are 0.5-1.0 inches in diameter with hard edges and soft center -IN males occurs on lans or corona of penis, in females occur on vulva, cervix or vaginal wall -once resolution of chancre primary stage is over
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Syphilis: secondary stage
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-develops 2-6 weeks after the primary stage -rash develops on upper body, upper extremities, and other areas of skin, rash painless and not itchy - other symptoms include hair loss, sore throat, swollen lymph nodes, painful joints, and poor appetite -secondary stage goes away after 2-6 weeks but may recur over next two years -Person is contagious
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Syphilis: latent stage
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-People are not contagious, except for pregnant women who can transmit it to fetus - Can last for years, and person will have no or few symptoms -half of patients who enter latent phase, never progress onto tertiary phase
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Syphilis: Tertiary stage
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-Tertiary phase develops as microbe invades tissue throughout the body and develops large tumor-like gummas in skin, muscle, intestine, liver heart, and endocrine glands, eyes, brain & spinal cord - people in tertiary stage are NOT contagious except for women who can transmit to fetus
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Tertiary cardiovascular syphilis
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Develops 10-40 years after infection resulting in infection of the heart and blood vessels which can be fatal
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Tertiary neurosyphilis
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develops 10-20 years after infection when the central nervous system are infected -they can develop blindness, paralysis, dementia, psychosis, and death
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Congenital Syphilis stats
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-each year one to two million pregnant women have active syphilis in pregnancy -30% of these fetuses miscarry -70% are born with congenital syphilis and are contagious for 2 years of life - If untreated over 20% will go onto develop tertiary syphilis in 10-20 yrs
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congenital syphilis
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-infected women in ALL stages can pass syphilis onto their fetus inn the 3rd trimester of pregnancy -congenital syphilis includes blindness, deafness, flattening of the bridge of the nose, notched central incisor teeth
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Syphilis diagnosis& treatment
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-diagnosed with VDRL and RPR blood test -treatment: benzathine penicillin G injected, tetracycline, or erythromycin
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US government sanctioned studies on syphilis i Guatemala
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- between 1946-1948 a US government study in Guatemala intentionally infected at least 700 men and women to test the effects of penicillin on STIs -Experiments were led by US public health physician John Charles Cutler
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US government sanctioned studies on syphilis
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-Between 1932-1972 infamous clinical study conducted in Tuskegee, Alabama by US public health service to study the natural progression of untreated syphilis in poor, rural, black men who thought they were being given free health care -investigators enrolled 600 impoverished sharecroppers 399 who had previously contracted the disease and 201 without the disease -they were never given treatment though penicillin was widely available, men were given free healthcare and free burial services
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Human papilloma virus (HPV)
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-of 100 types of HPV over 40 are sexually transmitted - female genital tissues that may be infected: vulva, perineum, labia, cerivix -male genital tissues affected: prepuce, glands, coronal ridge, urethra, and scrotum -anal area can be infected in either sex
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HPV statistics
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-20million americans are infected with HPV -half of these 20 mil are adolescents and young adults 15-24 yrs old 20% of sexually active 14-18 year old females have this virus most sexually active adults become infected with HPV at some time in life
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HPV signs and symptoms
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-most infections are asymptomatic and transient and most people will not have symptoms and the virus clears on its own - certain types of human papilloma virus cause genital warts (condyloma acuminata) -soft cauliflower like warts appear 3 weeks to 8 months after exposure -these types of HPV are not associated with cancer -about 1% of sexually active men and women in USA have genital warts at any given time
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HPV & cervical and anal cancer
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strong association between infection with certain types of papilloma virus and development of cervical cancer - 4 types are known to be associated with cervical cancer(HPY-16, 18, 31, and 45) - association of the HPV and anal cancer with men and women who have anal sex 1/3 of adults polled in US report having anal sex
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HPV & mouth and throat cancer
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-oral sex exposes mouth to genitalia -HPV induced mouth and throat cancer has increased in past 25 years - 7% of american teens and adults carry HPV in their mouth
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oral sex statistics
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90% of USA adults, 27% of 15 year old males, and 23% of 15 year old females reported having oral sex
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HPV diagnosis treatment & prevention
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Prevention: condoms, HPV vaccine Diagnosis: antibody tests and DNA tests for HPV types from cervical cells, pap smear of cervix to rule out development of cancer Treatment: podophyllin-antimitotic agent, imquimod-immunosuppresant, liquid nitrogen
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HPV vaccine
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Gardisil for the prevention of 4 different types of HPV -protects against HPV 16&18 which cause 70% of cervical cancer -protects against HPV 6& 11which cause 90% of genital warts - three doses recommended for females and males 9-26 yrs old
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Herpes Simplex 2 virus
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-infection results in retention of the virus in nerve fibers for life -mainly infects genital area but can occur within oral cavity form oral sex -typically transmitted form person to person who has an active lesion
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Herpes simplex 2 Signs
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-through genital, anal or oral contact tiny blisters develop that change into painful round sores in 4-7 days and may progress to ulcers Males: prepuce, glans, urethra, shaft Female: labia, prepuce, urethral orifice, vaginal introitus and cervix -Lesions usually resolve in 1-2 weeks -Virus remains dormant in sensory nerve fibers and intermittent recurrences of skin lesions may occue
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Herpes Simplex 2 diagnosis
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PCR culture of tissue
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Herpes simples 2 treatment
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acyclovir by mouth can limit the frequency and length of outbreaks
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Herpes 1 vs Herpes 2
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herpes simplex 1 causes cold sores around mouth, infects 90% of adults - herpes 1 is similar to herpes 2 and can also infect around genitalia can result from oral sex
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congenital herpes simplex
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-if a mother has active genital lesions at the time of vaginal delivery the newborn can potentially acquire herpes simplex and result in infant death -women with active lesions are recommended to have a C section -newborns with herpes simplex are treated with IV acyclovir
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Hepatitis C and B
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-Hep B is small circular DNA virus in hepadnavirus family while Hep C is linear single stranded RNA virus in flaviviridae family -both are primarily transmitted through blood so they can be sexually transmitted when there is exposure to blood -very effective vaccine for Hep B given to infants and for all ages
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HIV-blood borne infection
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derived from african primates both HIV1 and 2 are believed to have emerged in west ¢ral africa in humans in early 20th century
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HIV1
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came from SIV-1 in chimps in Africa -originated in southern cameroon thorough evolution of SIV, a simian immunodeficiency virus that infects wild chimp
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HIV2
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came from SIV-2 in sooty mangabey monkeys in Africa derived from SIVa monkey living in west africa from southern senegal to western cote d ivore
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SIV origin
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-is at least between 32000 and 75000 years old and may even be more than a million years old exposure to blood drom butchered primates leads to infection with SIV
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SIV to HIV
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SIV is a weak virus and is typically suppressed and cleared several transmissions of the virus from person to person in quick succession are required to allow it enough time to mutate into HIV
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SIV in population
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due to SIVs low person to person transmission rate it can only spread thorough a population in the presence of one or more high risk transmission channels, absent in Africa prior to 20th century
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HIV origin
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1910 most recent common ancestor of HIV M group dates back to circa 1910 direct evidence of HIV 1 in Kinshasa in central africa by 1960 -earliest documented case is 1959 in Congo
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Emergence of large african cities linked to HIV emergence
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HIV epidemic is linked with emergence of colonialism and growth of large African cities in early 20th century , increase in prostitution along with its associated high frequency of genital ulcer diseases increases rick of HIV transmission
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Unsterile syringe injections and HIV emergence
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serial human passage of SIV and HIV by unsterile syringe injection contributed to emergence of epidemic human HIV virus in africa
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Earliest description of AIDSin US
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AIDS caused by HIV was first clinically described in 1981 in LA
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Mutation at CCR5
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-CCR5 human receptor protein based on selection caused by some prior infectious disease may provide protection against HIV widespread occurrence of a mutation in CCRS gene appears to provide partial resistance to HIV infection
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HIV transmission
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-HIV is present in blood, semen , cervical & vaginal secretions -primarily transmitted in blood
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HIV transmission routes
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-blood inoculation eg injection drug use -perinatal across placenta, during birth, breastfeeding -sex: sores on genital or anal area from from another infection make it easier to be infected with HIV
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Circumcision and transmission
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circumcised men are 50% less likely to acquire HIV through sex also less likely to acquire other STIs
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Circumcision and herpes and HPV
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3000 men in uganda studied found: circumcised men had 25% reduction in risk of contracting herpes simplex 2 , 35 % reduction in risk of contracting HPV types that cause cancer
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HIV diagnosis
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-detection of HIV antibodies in blood or saliva nearly all persons infected with HIV have detectable antibodies within 6 months of infection -viral RNA tests can detect virus before antibodies emerge
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HIV prevention
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-condoms for both men and women -circumcision -breast milk can be heated to low temperature to eliminate HIV HIV positive women pregnant receive AZT during pregnancy labor and delivery and newborn receives AZT -truvada taken orally each day to prevent HIV infection contains NRTI medicines
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Treatment
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-Nucleoside reverse transcriptase inhibitors (NRTI) ez AZT interfere with synthesis of viral DNA -Non nucleoside reverse transcriptase inhibitors (NNRTI) -Protease inhibitors: interfere with correct cutting of viral proteins -Fusion inhibitors prevent passage of virus into cell
