MICR J210 1st Edition Lecture 20Outline of Last Lecture 1. What are Viruses?2. Reasons to Study Viruses3. Viral Pathogenicity4. Life Cycle of a Virus5. Viral VaccinesOutline of Current Lecture I. Herpes virusesHerpes simplex I and II virus: cold sores, genital herpesVaricella zoster virus (VZV): chickenpox, shinglesEpstein-Barr Virus (EBV): infectious mononucleosisCytomegalovirus (CMV): CMV mononucleosis II. Adenovirus: conjunctivitis, diarrheaIII. ParvovirusIV. Human papilloma virus (HPV): wartsCurrent Lecture- Herpes viruseso Herpes simplex I and II virus: cold sores, genital herpes Herpes simplex I- Diseases by HSV Io Oral gingivostomatitis(Herpes labialis: cold sores) Incubation time-2-12 days Duration of disease: 10-14 days Very painful sores with fever and sore throat Can pop up whenever the immune system is suppressedThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Other sites that have the same disease but different names: Eczema herpeticum - burn patients- Infection of the skin Herpes gladitorium– wrestlers Herpes whitlow - medical personnel - skin break in fingers Encephalitis - Nerves, occasionally goes up to brain - 80% die without treatment- Usually a primary infection that travels to the brain Herpes keratitis - ulcers in eye, lasts 2 to 3 weeks, can lead to blindness especially during recurrence- Diseases by HSVIIo Genital herpes in sexually active adults Sexually transmitted disease Blister-like sores on genital organso Disseminated disease of newborn Babies get infected during birth 85% get disseminated disease involving liver, spleen, CNS causing permanent sequelaeo Disseminated disease of immunocompromised patients May lead to encephalitis (i.e. AIDS, Cancer, transplant patients) Recurrence of HSV- The virus stays dormant in nerve cells where the immune system is unable to attack. o Invisible and unreachable by the antibodies- The virus can be reactivated by stress, UV light (sun tanning), cold,fever, hormonal fluctuations, certain foods, etc- Once latency is established, recurrence is possible- Happens in both HSV I and HSV II infectiono Most people are infected as children Epidemiology of HSV- First infection will cause seroconversion from seronegative to seropositiveo HSV I - 90% of the cases above the waist - contact with oralsecretionso HSV II - 90% of the cases below the waist - direct sexual contact – STD- 80% of humans have antibodies to HSV I by age 5: 25% will have recurrence- In the US, there are 600,000 new cases of HSV II appear every year- Recent studies show that 1 in 4 Americans 12 and older is infectedby HSV IIo Only 25% of primary infections cause latent infections Depends on how strong your immune response was to the primary infection Once you have the latent infection you can never get rid of it Treatment of HSV Infections- Acyclovir is the best drug in general for all types, also a new drug Famcycloviro Taken up by the virus and replaced guanine in viral DNAo Blocks DNA replication of the virus in the host cello Acyclovir works well for HSV and chickenpox- Keratitis - Iododeoxyuridine (IUdR) - Topical use only- Encephalitis - Acyclovir- Disseminated disease - acyclovir for the immunocompromised- For treatment of RECURRENT DISEASEo Acyclovir (topical or oral) works if given early. Can also be given to prevent recurrence of genital herpes Shortens the duration of the lesiono All these drugs inhibit viral DNA replication Prevention of HSV infections- Medical personnel always wear gloves - Teach your patient - open genital lesion - avoid any spread to othero Envelope viruses are sensitive to detergent so wash sheets and clothes that have been in contact with lesions- Avoid sexual contact with someone who may be infected- If the pregnant mother has active lesions, recommend a C-section- Avoid undue stress, excess sunlight, greasy foods and cosmetics toprevent recurrence- Condoms can reduce spread up to 80 or 90%. - VACCINE:o Vaccine is currently being tested. We hope it works!o Varicella zoster virus (VZV): chickenpox, shingles Primary disease RecurrenceChicken pox Shingles  Chicken pox:- One of the most highly contagious disease known. 96% of exposedindividuals contract the disease, mostly as young children  Virus -> URT -> Lymph -> Blood -> Internal organs and skin  Incubation period about 15 - 18 days Disease lasts 2 - 3 weeks Symptoms of chicken pox (VZV)- Rash, a few to 1000s of lesions- Raised vesicles that are soft and watery, Mostly on skin, but in themouth and internal organs too (In crevices and hollow areas of thebody). Intense itching- Highly contagious 1 - 2 days before rash to 6 days after it disappears via air or pox fluid- Usually a very mild disease, although occasionally may lead to pneumonia and encephalitis in the young- In older individuals, it is more serious, up to 20% fatal. [100 deaths/yr] It is better to get it as a child and get it over with - Pregnant mothers !!!o Can pass on the virus to the fetus transplacentally, where it can cause a serious progressive disease, especially in the first trimester.  A common cause of hearing loss in infants Shingles- Recurrent disease caused by VZVo Virus remains latent in cranial nerve cells, and following activation (fatigue or sunburn), causes lesions at nerve endings usually in the skino Very painful rash usually appearing on one side of the face or body and lasts from 3-5 weeks. fairly long!o Fever may or may not be presento Mostly in older individuals  Treatment and Prevention of VZV Infections- Treatment for both chicken pox and shingles is supportive- NEVER USE ASPIRIN FOR KIDS - REYE'S SYNDROME SCAREo Can keep fever down with acetominophen (Tylenol)- Trim fingernails, Frequent showers- A new drug VIDARABINE is recommended as an antiviral agent- Newborn and immunodeficient patients can be given ZOSTER IMMUNE GLOBULIN (ZIG) from recurrent patients – “passive immunization“o Good for infants or immunosuppressed patients- Chicken pox vaccine (Live, attenuated): Varivax, became available in 1995. - It is ~85% effective for chicken pox.- Shingles vaccine: Zostavax® is used to prevent shingles, o Recommended for people 60 years or older. 50% effective.o Can be given to persons who have already had an episode of shingleso Epstein-Barr