208 - Microbiology - Unit 4 - STI



This outline is intended to facilitate your preparation for lecture. This web outline will NOT substitute for regular lecture attendance.E. Sexually Transmitted Infections (STI = STD = VD)MMWRTABLE II. Provisional cases of selected notifiable diseases, United States.2010Reporting AreaPopulationHepatitis BSyphilisGonorrheaChlamydiaMichigan10,071,82212520713,31748,286U. S.303,755,2744,73712,164280,5551,194,652What all STIs have in common:Transmission – direct mucosal contact with infected individualAsymptomaticCan be acquired multiple timesHaving one predisposes you for the othersCan cause infertility and other permanent complicationsPrevention – Abstinence – the only guaranteeMonogamyLatex condomsRegular screening – all sexually active women should be screened for STIs every 6 months!Disease – Gonorrhea = “the clap”Agent – Neisseria gonorrhea (bacterium, GNC, oxidase +, humans only)Virulence - capsulefimbriaeinduces inflammation pusTransmission rate – female to male – 1 in 5male to female – 1 in 2Target organs – epithelial cells of the reproductive tract, including the cervix, uterus, and fallopian tubes in women, and the urethra in women and men. The bacterium can also grow in the mouth, throat, eyes, and anus.Clinical pictureIn men – 10% of men have no symptoms at all. 90% of men have symptoms that appear 2-5 days after infection; symptoms can take as long as 30 days to appear. Symptoms include a burning sensation when urinating, or a white, yellow, or green discharge from the penis. Sometimes men with gonorrhea get painful or swollen testicles.In women – In women, the symptoms of gonorrhea are often mild, but 50% of women who are infected have no symptoms at all. Even when a woman has symptoms, they can be so non-specific as to be mistaken for a bladder or yeast infection. The initial symptoms and signs in women include a painful or burning sensation when urinating, increased vaginal discharge, or vaginal bleeding between periods. Women with gonorrhea are at risk of developing serious complications from the infection, regardless of the presence of or severity of symptoms. Complications - Untreated gonorrhea can cause serious and permanent health problems in both women and men.In menpainful swelling of the testiclesdisseminated infectioninfertilityIn womenPelvic Inflammatory Disease (PID)ectopic pregnancydisseminated infectioninfertilityIn neonatesblindnessjoint infectionslife-threatening blood infectionsTreatment – Several antibiotics can successfully cure gonorrhea. However, drug-resistant strains of gonorrhea are increasing, and successful treatment of gonorrhea is becoming more difficult. Because many people with gonorrhea also have chlamydia, antibiotics for both infections are usually given together. Persons with gonorrhea should be tested for other STIs. Although antibiotic therapy will stop the infection, it will not repair any permanent damage done by the disease.Frequency – declining, but more than 700,000 persons in the U.S. get new gonorrheal infections/yr.Gonorrhea rates are highest among adolescents and young adults. The overall gonorrhea rate is highest for 20- to 24-year-olds, which is over 4 times higher than the national gonorrhea rate. Among females, 15- to 19- and 20- to 24-year-olds have the highest rates of gonorrhea; among males, 20-to 24-year-olds have the highest rate.Disease – Chlamydia or non-gonococcal urethritis or NGUAgent – Chlamydia trachomatis (bacterium, obligate intracellular)Chlamydia trachomatis infections are the most commonly reported notifiable disease in the U.S.Virulence – intracellular growth ruptures infected cells and induces inflammationTarget organs - the reproductive tract, including the cervix, uterus, and fallopian tubes in women, and the urethra in women and men. Clinical picture - Chlamydia is easily confused with gonorrhea because the symptoms of both diseases are similar and the diseases can often occur together. Chlamydia is usually asymptomatic (in 75% of women and 50% of men). Those who do have symptoms will experience them 1-3 weeks after infection and may have an abnormal discharge (mucus or pus) from the vagina or penis or experience pain while urinating. These early symptoms may be very plicationsIn menswelling of testicles or prostate glandinfertilityIn womenPelvic Inflammatory Disease (PID) (in 40% of untreated cases)ectopic pregnancyinfertility (the leading cause of)In neonatespremature deliveryblindnesspneumoniaTreatment – antibiotics (azithromycin)Frequency – the most frequently reported bacterial STI in U.S; more than 3 million people are newly infected each year.Among women, the highest age-specific rates of reported chlamydia are among 15- to 19-year-olds and 20- to 24-year- olds. These increased rates in women may be, in part, due to increased screening in this group. Age-specific rates among men, while substantially lower than the rates in women, were highest in the 20- to 24-year-olds.Disease – syphilis – “the great pox”Agent – Treponema pallidum (bacterium, GN spirochete)Virulence – enzyme hyaluronidase that degrades connective tissueClinical picture – infection may pass through multiple stages:The initial infection causes an ulcer at the site where bacteria enter the body. The bacteria, however, move throughout the body, damaging many organs over time. Medical experts describe the course of the disease by dividing it into four stages-primary, secondary, latent, and tertiary (late). Primary Syphilis – contagious stageThe first symptom of primary syphilis is an ulcer called a chancre. The chancre can appear within 10 days to 3 months after exposure, but it generally appears within 2 - 6 weeks. Because the chancre may be painless and may occur inside the body, the infected person might not notice it. I t usually is found on the part of the body exposed to the infected partner's ulcer, such as the penis, vulva, or vagina. A chancre also can develop on the cervix, tongue, lips, or other parts of the body. The chancre disappears within a few weeks whether or not a person is treated. Infection may be arrested by the immune system at this point, but if not treated during the primary stage, about 1/3 of people will go on to the chronic stages.Secondary syphilis – contagious stageA skin rash, with brown sores about the size of a penny, often marks this chronic stage of syphilis. The rash appears anywhere from 3 - 6 weeks after the chancre appears. While the rash may cover the whole body or appear only in a few areas, it is almost always on the palms of the hands and soles of the feet.Because active bacteria are present in the sores, any physical contact-sexual or nonsexual-with the broken skin of an infected person may spread the infection at this stage. The rash usually heals within several weeks or months.Other symptoms also may occur, such as mild fever, fatigue, headache, sore throat, patchy hair loss, and swollen lymph glands throughout the body. These symptoms may be very mild and, like the chancre of primary syphilis, will disappear without treatment. T he signs of secondary syphilis may come and go over the next 1 - 2 years of the disease.A pregnant woman with untreated, active syphilis is likely to pass the infection to her unborn child. In addition, miscarriage may occur in as many as 25 - 50% of women acutely infected with syphilis during pregnancy. Between 40 - 70% of women with active syphilis will give birth to a syphilis-infected infant.Some infants with congenital syphilis may have symptoms at birth, but most develop symptoms between 2 weeks and 3 months later. These symptoms may include skin ulcers rashes fever weakened or hoarse crying sounds swollen liver and spleen yellowish skin (jaundice) anemia (low red blood cell count) various deformities Latent syphilis – not contagiousIf untreated, syphilis may lapse into a latent stage during which the disease is no longer contagious and no symptoms are present. Many people who are not treated will suffer from no further signs and symptoms of the disease.Tertiary (= late) syphilis – not contagiousApproximately 1/3 of people who have had secondary syphilis go on to develop the complications of late, or tertiary, syphilis, in which the bacteria damage the heart, eyes, brain, nervous system, bones, joints, or almost any other part of the body. This stage can last for years, or even for decades. Late syphilis can result in mental illness, blindness, other neurologic problems, heart disease, and death.Treatment - Penicillin, given by injection. Unfortunately, the early symptoms of syphilis can be very mild, and many people do not seek treatment when they first become infected. People with neurosyphilis may need to be retested for up to 2 years after treatment. In all stages of syphilis, proper treatment will cure the disease. But in late syphilis, damage already done to body organs cannot be reversed.Frequency of syphilis– by Race/Ethnicity, Age, and SexAfrican Americans - highest among women aged 20-24 years and among men aged 25-29.non-Hispanic whites - highest among women aged 20-24 years and among men aged 35-39.Hispanics - highest among women aged 20-24 years and among men aged 35-39 years.Asian/Pacific Islanders - highest among women aged 20-24 years and among men aged 30-34.American Indian/Alaska Natives - highest among women aged 35-39 years and among men aged 30-34.FYIDisease – genital herpesAgent – Herpes Simplex virus (HSV-2, HSV-1) (Herpesviridae), ds DNA, envelopedClinical picturePrimary lesion 3-7 days post infectionLocal lymph nodes are swollen, may be fever, headacheHealing takes up to 2 wksBut virus travels up nerve endings to infect the neurons (persistent) at base of spineCan travel down to reactivate – 88%, every 3-4 monthsTreatmentNo cureAntiviral medications can shorten and prevent outbreaks during the period of time the person takes the medication. Daily suppressive therapy for symptomatic herpes can reduce transmission to partners.Frequency – very common in the U.S. At least 45 million people ages 12 and up, or 1 out of every 5 adolescents and adults. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download