Viral Diseases

1. Viral Diseases

2. Parvoviridae • Erythrovirus is human pathogen. • Causes lace like rash that lasts a few days. • Children 4-10 yrs. old most affected. • Transmission occurs during incubation period. • No longer infectious by appearance of rash.

3. Papovaviridae • Papilloma virus • Skin warts and genital warts • Various strains of Human Papilloma Virus (HPV). Each have preference for different body sites. • Grouped into 2 main categories: • 1)      cutaneous • 2)      mucosal • Incubation can be up to 2 years before signs or symptoms are detected. • Genome can persist in cells for years without outward signs. • Early genes stimulate proliferation of basal cells which causes the protruding papilloma (visible tissue or wart).

4. Cutaneous (plain old warts) • Transmission through skin abrasions • Commonly picked up from wet floors of public swimming pools and bathrooms • Subsequent spreading through scratching, picking, digging of wart. • Rx • Wart regresses spontaneously. • Cryotherapy (freezing with liquid Nitrogen) or injectible anti-cancer drugs are occasionally effective.

5. Mucosal • Transmission through abrasions during sexual intercourse • Can cause cancer by inactivation tumor suppressor gene products. The tumor suppress gene prevents the uncontrolled growth of cells. When it’s function is compromised uncontrolled cell growth is allowed causing tumors. • Cervical carcinomas may develop 20-50 years post infection because the genome of the virus persists in the infected cells. • Rx • Laser • Surgery • Vaccination: currently testing vaccine against mucosal strains • “On average, there are 9,710 new cases and 3,700 deaths from cervical cancer in the United States each year.

6. HPV is the most common sexually transmitted infection in the United States, More than 20 million men and women in the United States are currently infected with HPV and there are 6.2 million new infections each year. HPV is most common in young women and men who are in their late teens and early 20s. By age 50, at least 80 percent of women will have acquired HPV infection. • “Although an effective vaccine is a major advance in the prevention of genital HPV and cervical cancer, it will not replace other prevention strategies, such as cervical cancer screening for women or protective sexual behaviors,” said Dr. Schuchat “Women should continue to get pap tests as a safeguard against cervical cancer.”’ www.cdc.gov

7. Herpesviridae • 2 types of Herpes Simplex Virus • 1)  Herpes Simplex Virus 1 (HSV-1): cold sores, shed in saliva, contaminated hands, eating utensils, etc. • 2) HSV-2: sexual intercourse, through infected birth canal to infants • Varicella Zoster, Chickenpox/Shingles: to be covered in the group presentations.

8. Signs and Symptoms • infection causes groups of small, painful blisters. The fluid in the blisters may be clear or cloudy. The area under the blisters will be red. The blisters break open so easily that they quickly become open sores. • It may hurt to urinate. You may run a fever and have other flu-like symptoms.

9. Transmission • Spread by close person to person contact w/ lesions or mucosal secretions • Infects sensory neurons and remains for in the sensory neurons life, causing recurrent infections. • Initial infection is usually more severe w/ subsequent infections decreasing in frequency, duration, and severity. • Prevention and Rx • Avoid contact when lesions are present. • Use condoms during sexual intercourse whether or not lesions are present. • Acyclovir • Inhibits DNA polymerase • Helps to further decrease the frequency and duration of subsequent outbreaks.

10. Caliciviridae • Norwalk virus • Responsible for most gastroenteritis cases • Signs and symptoms: • mild fever, nausea, vomiting, malaise, myalgia (muscle aches) • Transmission: Contact with infected body fluids, fomites. • Prevention: wash your hands frequently.

11. Picornaviridae • Poliovirus: Will be discussed at a later time. • Enteroviruses • Commonly infect children, produce life long immunity • Can cause meningitis, carditis, rashes (very common), sometimes colds or sore throats during summer, as well as other types of disease. • Transmitted mainly by close contact via fecal-oral route, droplet spread can also occur.

12. Rhinoviruses • Over 100 different rhinoviruses, which cause 50% of all colds • No possibility for vaccine yet • 3 or 4 rhinovirus types circulate among community simultaneously. • Virus shed in nasal secretions for 2-3 days. • Transmission • Spread through sneezing, coughing, contamination of hands, handkerchiefs, any other fomites, to nose or eye. • Because generally acquire cold during cold weather, has generated myth that if exposed to cold weather will get a cold. Remember that it is the organism that causes the cold, not the weather or how little clothing one is wearing. However, the weather and clothing can be predisposing factors for acquiring an illness.

13. Hepatitis A • Similar symptoms to Hepatitis B • Preicteric phase: malaise, anorexia, nausea, and lethargy aren’t as bad, don’t last as long • Icteric phase: Hepatomegaly may produce pain in the right upper abdominal quadrant, followed by bilirubinuria, then pale feces and jaundice. • Convalescent phase: signs and symptoms decrease, virus is eliminated from body. • Transmission • Oral-Fecal route. Virused passed in the feces of an infected person. It is transmitted when an infected individual fails to wash his hands after going to the bathroom, etc. • Multiplies in intestinal cells before entering blood stream and infecting liver

14. Incubation period is about 4 weeks • Most infections occur in children (usually subclinical) • Illness usually last 4 weeks • Rx and prevention • Good public and personal hygiene • Vaccine for children, especially those exposed to other children on a daily basis such as in daycare

15. Orthomyxoviridae • Influenza • Signs and symptoms • Fever, sore throat, nonproductive cough, myalgia, headache, and malaise • Lasts 3-7 days • Complications depend on age of patient • Possible pneumonia, middle ear infection, croup • Susceptible to secondary bacterial infections

16. Transmission • Droplet (sneezing and coughing) • Short incubation period (1-4 days) • Antigens frequently mutate causing new strains, this is called an antigenic shift. • Influenza Type A undergoes an antigenic shift every 10-40 years. • Flu season is generally Oct. to Mar each year. • Note: The vaccine given to infants called Hemophilus influenzae is not the same as the flu vaccine. The bacteria mentioned above causes meningitis, not influenza.

17. Vaccine • Develop according to prevalent strain in other part of world • Recommend that elderly and under 2 receive vaccine as well as those more likely to be exposed such as care givers of young children. • The vaccine is made according to the strains that affect the other side of the world when it is not our flu season. The most prevalent strains are then used to manufacture the virus for our flu season. • If the strain mutates or if a new strain is introduced into the population after the virus has been manufactured, the vaccine probably won’t provide adequate protection against all strains of the virus. • Each year a new flu vaccine is recommended because the strains change from year to year.

18. Paramyxoviridae • Measles • highly contagious, characterized by a fever, cough, conjunctivitis (redness and irritation in membranes of the eyes), and spreading rash. • Symptoms • tiny white spots inside the mouth (called Koplik's spots) • photophobia (light sensitivity) • Rash, appears around the fifth day of the disease • Rash may last 4 to 7 days • The rash usually starts on the head and spreads to other areas, progressing downward

19. Koplik’s spots

20. Transmission • The infection is spread by contact with droplets from the nose, mouth, or throat of an infected person. • The incubation period is 8 to 12 days before symptoms generally appear. • Common Complications • Croup, bronchitis, bronchopneumonia (bacterial pneumonia most common cause of death in malnourished children)

21. Treatment • There is no specific treatment of measles, though some children may require supplementation with Vitamin A. • Symptomatic relief may be achieved with bed rest, acetaminophen, and humidified air • Prevent through vaccination

22. Mumps • Signs and Symptoms • Swollen, painful salivary glands on one or both sides of the face • Pain with chewing or swallowing, especially sour foods or beverages that promote saliva production • Fever • Weakness and fatigue • Tenderness and swelling of a testicle (orchitis)

24. Transmission • saliva and respiratory secretions • Treatment • Like most viral illnesses, mumps infection must simply run its course. Fortunately, most children and adults recover from an uncomplicated case of mumps within 2 weeks' time. • Prevention • vaccination

25. RSV (Respiratory Syncytial Virus) • Transmission • Highly contagious • Shed in respiratory secretions for several days, sometimes weeks • Incubation period is 4-5 days • Very severe in young infants, can cause death. • Signs and Symptoms • Most common manifestation is febrile rhinitis and/or pharyngitis • Virus multiplies in mucous membranes of the nose and throat • Fatal cases show extensive bronchiolitis and pneumonitis

26. Can cause impaired lung function for years and recurrent bouts of asthma • Infants can die due to difficulty breathing. • Vaccine is available but it only helps in recovery, not in avoiding disease.

27. Coronaviridae • SARS • “According to the World Health Organization (WHO), a total of 8,098 people worldwide became sick with SARS during the 2003 outbreak. Of these, 774 died. In the United States, only eight people had laboratory evidence of SARS-CoV infection. All of these people had traveled to other parts of the world with SARS. SARS did not spread more widely in the community in the United States.” • www.cdc.gov

28. Symptoms: “In general, SARS begins with a high fever (temperature greater than 100.4°F [>38.0°C]). Other symptoms may include headache, an overall feeling of discomfort, and body aches. Some people also have mild respiratory symptoms at the outset. About 10 percent to 20 percent of patients have diarrhea. After 2 to 7 days, SARS patients may develop a dry cough. Most patients develop pneumonia.” • www.cdc.gov

29. Transmission: “The virus that causes SARS is thought to be transmitted most readily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes. Droplet spread can happen when droplets from the cough or sneeze of an infected person are propelled a short distance (generally up to 3 feet) through the air and deposited on the mucous membranes of the mouth, nose, or eyes of persons who are nearby. The virus also can spread when a person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, nose, or eye(s). In addition, it is possible that the SARS virus might spread more broadly through the air (airborne spread) or by other ways that are not now known.” • www.cdc.gov

30. “SARS is clearly spread by droplet contact. When someone with SARS coughs or sneezes, infected droplets are sprayed into the air. Like other coronaviruses, the SARS virus may live on hands, tissues, and other surfaces for up to 6 hours in these droplets and up to 3 hours after the droplets have dried. • While droplet transmission through close contact was responsible for most of the early cases of SARS, evidence began to mount that SARS might also spread by hands and other objects the droplets had touched. Airborne transmission was a real possibility in some cases. Live virus had even been found in the stool of people with SARS, where it has been shown to live for up to four days. And the virus may be able to live for months or years when the temperature is below freezing. • With other coronaviruses, re-infection is common. Preliminary reports suggest that this may also be the case with SARS. • Preliminary estimates are that the incubation period is usually between 2 and 10 days, although there have been documented cases where the onset of illness was considerably faster or slower. People with active symptoms of illness are clearly contagious, but it is not known how long contagiousness may begin before symptoms appear or how long contagiousness might linger after the symptoms have disappeared. • Reports of possible relapse in patients who have been treated and released from the hospital raise concerns about the length of time individuals can harbor the virus.” • www.nlm.nih.gov/medlineplus

31. Treatment: People suspected of having SARS should be evaluated immediately by a physician and hospitalized under isolation if they meet the definition of a suspected or probable case. • Antibiotics are sometimes given in an attempt to treat bacterial causes of atypical pneumonia. Antiviral medications have also been used. High doses of steroids have been employed to reduce lung inflammation. In some serious cases, serum from people who have already gotten well from SARS (convalescent serum) has been given. Evidence of general benefit of these treatments has been inconclusive. • Other supportive care such as supplemental oxygen, chest physiotherapy, or mechanical ventilation is sometimes needed.

32. Prevention: Minimizing contact with people with SARS minimizes the risk of the disease. This might include minimizing travel to locations where there is an uncontrolled outbreak. Where possible, direct contact with people with SARS should be avoided until at least 10 days after the fever and other symptoms are gone. • The CDC has identified hand hygiene as the cornerstone of SARS prevention. This might include hand washing or cleaning hands with an alcohol-based instant hand sanitizer. • People should be taught to cover the mouth and nose when sneezing or coughing. Respiratory secretions should be considered to be infectious, which means no sharing of food, drink, or utensils. Commonly touched surfaces can be cleaned with an EPA approved disinfectant. • In some situations, appropriate masks and goggles may be useful for preventing airborne or droplet spread. Gloves might be used in handling potentially infectious secretions.

33. Flaviviridae • West Nile Encephalitis • “West Nile virus is transmitted by mosquitos and causes an illness that ranges from mild to severe. Mild, flu-like illness is often called West Nile fever. More severe forms of disease, which can be life-threatening, may be called West Nile encephalitis or West Nile meningitis, depending on where it spreads.” • www.nlm.nih.gov/medlineplus

34. “West Nile virus was first identified in 1937 in the West Nile region of Uganda, in eastern Africa. It was first identified in the US in the summer of 1999 in the Queens borough of New York, NY. It caused 62 cases of encephalitis and 7 deaths that summer. Since 1999 the virus has spread throughout the continental US and as of July 2004 has been identified in 46 states. • Mosquitos carry the highest amounts of virus in the early fall, thus there is a peak of disease in late August-early September. The risk of disease then decreases as the weather becomes colder and mosquitos die off. • Although many people are bitten by mosquitos that carry West Nile virus, most do not know they've been exposed. Few people develop severe disease or even notice any symptoms at all.” • www.nlm.nih.gov/medlineplus

35. Symptoms: • Fever • Headache • Back pain • Muscle aches • Lack of appetite • Sore throat • Nausea • Vomiting • Abdominal pain • Diarrhea • These symptoms usually last for 3 to 6 days. • With more severe disease, the following symptoms can also be seen and require prompt attention: • Muscle weakness • Stiff neck • Confusion or change in clarity of thinking • Loss of consciousness • www.nlm.nih.gov/medlineplus

36. Diagnosis: “The most accurate way to diagnose this infection is serology, a test to detect the presence of antibodies against West Nile virus in CSF or serum (a blood component). This is considered the gold standard for diagnosis.” www.nlm.nih.gov/medlineplus • Treatment: “Because this illness is not caused by bacteria, antibiotics do not help treat West Nile virus infection. Standard hospital care may help decrease the risk of complications in severe illness. There is no human vaccine available at present, and it is likely there will not be one for several years. • Research trials are under way to determine whether ribavirin, an antiviral drug used to treat hepatitis C, may be helpful.” • www.nlm.nih.gov/medlineplus

37. Prevention: “The best way to prevent West Nile virus infection is to avoid mosquito bites. Using mosquito-repellant products containing DEET and wearing long sleeves and pants are the most effective way to avoid bites. Community spraying for mosquitos may also prevent mosquito breeding. • Mosquitos breed in stagnant water. If you notice pools of standing water -- even in small areas such as trash bins and plant saucers -- drain them promptly. • Testing of donated blood and organs is currently being evaluated. There are no guidelines at present.” • www.nlm.nih.gov/medlineplus

38. Rabdoviridae • Rabies-addressed a later time.

39. Retroviridae • HIV/AIDS • See Fig. 20.21 for the viral replication strategy. • The most important thing to understand about HIV is that it can hide out in the host cell chromosomes for extended periods of time. When the conditions are right, the virus will begin the viral replication cycle, make and release virions. • HIV is not AIDS • AIDS is when the provirus becomes an active virus, destroying T-helper cells of the immune system, thus compromising the immune system.

40. Transmission: • “HIV is spread by sexual contact with an infected person, by sharing needles and/or syringes (primarily for drug injection) with someone who is infected, or, less commonly (and now very rarely in countries where blood is screened for HIV antibodies), through transfusions of infected blood or blood clotting factors. Babies born to HIV-infected women may become infected before or during birth or through breast-feeding after birth. • In the health care setting, workers have been infected with HIV after being stuck with needles containing HIV-infected blood or, less frequently, after infected blood gets into a worker’s open cut or a mucous membrane (for example, the eyes or inside of the nose). There has been only one instance of patients being infected by a health care worker in the United States; this involved HIV transmission from one infected dentist to six patients.” • www.cdc.gov

41. Prevention: • “Gloves should be worn during contact with blood or other body fluids that could possibly contain visible blood, such as urine, feces, or vomit. • Cuts, sores, or breaks on both the care giver’s and patient’s exposed skin should be covered with bandages. • Hands and other parts of the body should be washed immediately after contact with blood or other body fluids, and surfaces soiled with blood should be disinfected appropriately. • Practices that increase the likelihood of blood contact, such as sharing of razors and toothbrushes, should be avoided. • Needles and other sharp instruments should be used only when medically necessary and handled according to recommendations for health-care settings. (Do not put caps back on needles by hand or remove needles from syringes. Dispose of needles in puncture-proof containers out of the reach of children and visitors.)” • www.cdc.gov

42. “Condoms are classified as medical devices and are regulated by the Food and Drug Administration (FDA). Condom manufacturers in the United States test each latex condom for defects, including holes, before it is packaged. The proper and consistent use of latex or polyurethane (a type of plastic) condoms when engaging in sexual intercourse--vaginal, anal, or oral--can greatly reduce a person’s risk of acquiring or transmitting sexually transmitted diseases, including HIV infection.” • www.cdc.gov

43. Perinatal HIV Transmission • “Accounts for nearly all pediatric AIDS cases. HIV transmission from mother to child during pregnancy, labor and delivery or by breast feeding accounted for approximately 91% of all AIDS cases reported among U.S. children between 1985 and 2004 (1). • Can be prevented. Data indicate that when appropriate antiretroviral medications are given during pregnancy, labor and delivery and after birth, the risk of transmission can be reduced to less than 2% (2) compared with approximately 25% when no interventions are given (3).” • www.cdc.gov • Vaccine: a vaccine is still years away. It is difficult to develop a vaccine for HIV because it is constantly mutating. • Be sure to read more about HIV and AIDS in your textbook, pgs. 636-645,

44. Treatment: • Reverse Transcriptase Inhibitors-block the action of reverse transcriptase preventing the production of viral DNA and insertion into the host chromosomes. • Protease Inhibitors-inhibit the final assembly and maturation of viral particles. • Fusion Inhibitors-block the virus from fusing the with the host cell membrane. • Integrase Inhibitors-block the integration of the viral DNA into the host cell chromosome. • Usually one or more of these types of drugs are used at the same time. • Drug treatments seem to be more effective in combination with each other.

45. Prions and Viroids • Creutzfeldt-Jakob: prion disease • Prions are infectious proteins. It is not well understood where these proteins come from however there is some evidence that some prions begin as normal proteins made by the body, that mutate into an infectious form. • The most common form of classic CJD is believed to occur sporadically, caused by the spontaneous transformation of normal prion proteins into abnormal prions. This sporadic disease occurs worldwide, including the United States, at a rate of approximately one case per 1 million population per year, although rates of up to two cases per million are not unusual. The risk of CJD increases with age, and in persons aged over 50 years of age, the annual rate is approximately 3.4 cases per million. In recent years, the United States has reported fewer than 300 cases of CJD a year.

46. New variant Creutzfeldt-Jakob disease (vCJD) is an infectious form of CJD that is related to "mad cow disease" (bovine spongiform encephalitis ). The agent responsible for mad cow disease is believed to be the same agent responsible for vCJD in humans. This type of CJD was first described in 1996 in the United Kingdom. • New variant Creutzfeldt-Jacob disease accounts for less than 1% of cases, and tends to affect younger people. New variant CJD can result when someone is exposed to contaminated products.

47. Once symptoms appear, the disorder progresses rapidly and may be confused with other types of dementia -- like Alzheimer's disease. Both forms of CJD, however, are distinguished by extremely rapid progression from onset of symptoms to disability and death. Early symptoms include personality changes and difficulty with coordination. • Creutzfeldt-Jakob disease may be related to several other diseases also thought to be caused by prions, including kuru (seen in New Guinea women who ate the brains of deceased relatives as part of a funerary ritual), scrapie (found in sheep), and other rare human diseases, such as Gerstmann-Straussler-Scheinker disease and fatal familial insomnia.

48. Symptoms: • Personality changes • Hallucinations • Muscle twitching • Muscle stiffness • Nervous, jumpy feelings • Changes in gait (walking, locomotion) • Lack of coordination -- stumbling, falls • Speech impairment • Poor enunciation (hard-to-understand speech or mumbling) • Sleepiness • Delirium or dementia develops rapidly • Deterioration in all aspects of brain function • Profound confusion, disorientation • Additional symptoms that may be associated with this disease: • Memory loss • Anxiety, stress, and tension

49. Treatment: There is no known cure for Creutzfeldt-Jakob disease. Custodial care may be required early in the course of the disease. Medications may be needed to control aggressive behaviors. These include sedatives, antipsychotics, and others. • The need to provide a safe environment, control aggressive or agitated behavior, and meet physiologic needs may require monitoring and assistance in the home or in an institutionalized setting. Family counseling may help in coping with the changes required for home care. • Visiting nurses or aides, volunteer services, homemakers, adult protective services, and other community resources may be helpful in caring for the person with Creutzfeldt-Jakob disease. • Behavior modification may be helpful, in some cases, for controlling unacceptable or dangerous behaviors. This consists of rewarding appropriate or positive behaviors and ignoring inappropriate behaviors (within the bounds of safety). Reality orientation, with repeated reinforcement of environmental and other cues, may help reduce disorientation.

50. Legal advice may be appropriate early in the course of the disorder, to form advance directives, power of attorney, and other legal actions that may make it easier to make ethical decisions regarding the care of an individual with Creutzfeldt-Jakob disease. • Expectations (prognosis) • The outcome is usually very poor. Complete dementia commonly occurs within 6 months or less of the onset of symptoms, with the person becoming totally incapable of self-care. • The disorder is fatal in a short time, usually within 7 months, but a few people survive as long as 1 or 2 years after diagnosis of the disorder. The cause of death is usually infection, heart failure, or respiratory failure.