Micropara

• Cold sores


  Superficial clear vesicles on an erythematous (reddened) base, which may appear on the face or lips. They crust and heal within a few days.
• Reactivation of cold sores may be caused by

  Trauma, fever (hence the name), physiologic changes, or disease
• Cold sores


  Usually caused by herpes simplex virus type 1 (HSV-1), but may also be caused by herpes simplex virus type 2(HSV-2). They are DNA viruses in the family Herpesviridae.
• Either HSV-1 or HSV-2 may also infect the genital tract, although genital herpes infections are most often caused by HSV-2.
• Diarrhea


  Can have many causes, including viruses, bacteria, protozoa, or helminths.
• Dysentery


  A severe form of diarrhea, may be caused by bacteria (e.g., Shigella spp.) or protozoa (e.g., those that cause amebiasis and balantidiasis)
• Viral gastroenteritis


  Also known as viral enteritis or viral diarrhea, may be an endemic or epidemic illness. Sometimes referred to as "stomach flu".
• Viral gastroenteritis


  • Symptoms include nausea, vomiting, diarrhea, abdominal pain, myalgia, headache, malaise, and low-grade fever.
  • Often self-limiting but can be fatal in infants or young children, especially when caused by rotavirus.
• Use Standard Precautions and Contact Precautions for diapered or incontinent patients with viral gastroenteritis.
• Viruses that commonly infect children in their first years of life

  • Enteric adenoviruses
  • Astroviruses
  • Caliciviruses (including noroviruses)
  • Rotaviruses
• Viruses that commonly infect children and adults

  • Norovirus-like viruses
  • Rotaviruses
• Reservoirs for viral gastroenteritis


  Infected humans, contaminated water and shellfish
• Transmission of viral gastroenteritis

  Most often via the fecal–oral route. Airborne and contact with contaminated fomites may cause epidemics in hospitals or cruise ships. Foodborne, waterborne, and shellfish transmission have been reported.
• Diagnosis of viral gastroenteritis

  By electron microscopic examination of stool specimens or by immunodiagnostic or molecular procedures.
• Hepatitis


  Inflammation of the liver, can have many causes, including alcohol, drugs, and viruses.
• Viruses that can cause viral hepatitis

  • Hepatitis A virus (HAV)
  • Hepatitis B virus (HBV)
  • Hepatitis C virus (HCV)
  • Hepatitis D virus (HDV)
  • Hepatitis E virus (HEV)
  • Hepatitis G virus (HGV)
  • Hepatitis GB virus A (HGBV-A)
  • Hepatitis GB virus B (HGBV-B)
  • Hepatitis GB virus C (HGBV-C)
• Hepatitis can also occur as a result of viral diseases such as infectious mononucleosis, yellow fever, and cytomegalovirus infection.
• Use Standard Precautions and Contact Precautions for diapered or incontinent patients with viral hepatitis.
• Diagnosis of viral hepatitis

  Various immunodiagnostic procedures are available.
• The World Health Organization (WHO) estimates that ∼240 million people are chronically infected with HBV worldwide, that about 600,000 people die each year as a result of HBV infections, and that more than 2 million new acute clinical cases occur annually.
• Initial symptoms of HIV infection

  An acute, self-limited mononucleosis-like illness lasting 1 or 2 weeks.
• Acute HIV infection is often undiagnosed or misdiagnosed, because anti-HIV antibodies are usually not present in a high enough concentration to be detected during this early phase of infection.
• Other signs and symptoms of HIV infection

  • Fever
  • Rash
  • Headache
  • Lymphadenopathy
  • Pharyngitis
  • Myalgia (muscle pain)
  • Arthralgia (joint pain)
  • Aseptic meningitis
  • Retro-orbital pain
  • Weight loss
  • Depression
  • GI distress
  • Night sweats
  • Oral or genital ulcers
• Without appropriate antiHIV treatment, approximately 90% of HIV-infected individuals ultimately develop AIDS.
• AIDS


  A severe, life-threatening syndrome that represents the late clinical stage of infection with HIV. Invasion and destruction of helper T cells leads to suppression of the patient's immune system (immunosuppression).
• Complications of AIDS


  Secondary infections caused by viruses, protozoa, bacteria, and/or fungi become systemic and cause death.
• Kaposi's sarcoma


  A frequent complication of AIDS, thought to be caused by a type of herpes virus called human herpesvirus 8.
• Certain combinations of drugs, referred to as cocktails, are extending the life of some HIV-positive patients. In the absence of effective anti-HIV treatment, the AIDS case–fatality rate is very high—approaching 100%.
• HIV


  Single-stranded RNA viruses in the family Retroviridae (retroviruses). Type 1 (HIV-1) is the most common type, and type 2 (HIV-2).

  
• Reservoirs and transmission of HIV

  Infected humans serve as reservoirs. Transmission occurs via direct sexual contact (homosexual or heterosexual); sharing of contaminated needles and syringes by intravenous drug abusers; transfusion of contaminated blood and blood products; transplacental transfer from mother to child; breast-feeding by HIV-infected mothers; transplantation of HIV-infected tissues or organs; and needlestick, scalpel, and broken glass injuries. There is no evidence of HIV transmission via biting insects.
• Progression of HIV infection

  Most likely, HIV-1 first invades dendritic cells in the genital and oral mucosa. These cells then fuse with CD4+ lymphocytes (helper T cells) and spread to deeper tissues.
• Diagnosis of HIV infection

  Immunodiagnostic procedures are available for detection of antigen and antibodies. Most HIV infected patients develop detectable antibodies within 1–3 mo after infection. However, there may be a more prolonged interval of up to 6 mo, or even longer in some cases. The most commonly used screening test is an enzyme-linked immunosorbent assay (ELISA). If the screening test is positive, a confirmatory test such as the Western blot analysis or indirect fluorescent antibody test is usually performed. Antigen detection procedures detect an HIV antigen known as p24. Molecular diagnostic procedures are also available. Quantitative assessment of viral RNA is used to monitor the effectiveness of antiviral therapy.
• Infectious mononucleosis


  An acute viral disease that may be asymptomatic or may be characterized by fever, sore throat, lymphadenopathy (especially posterior cervical lymph nodes), splenomegaly (enlarged spleen), and fatigue. It is usually a self-limited disease of 1 to several weeks' duration and is rarely fatal.
• Etiologic agent of infectious mononucleosis

  Epstein–Barr virus (EBV; human herpesvirus, a DNA virus in the family Herpesviridae). EBV infects and transforms B cells and other types of cells. EBV is known to be oncogenic associated with lymphomas, carcinomas, and sarcomas, among other cancers.
• Reservoirs and transmission of EBV

  Infected humans. Transmission occurs person to person by direct contact with saliva. Kissing facilitates spread among adolescents. EBV can also be transmitted via blood transfusion.
• Diagnosis of infectious mononucleosis

  Lymphocytosis (abnormally high peripheral lymphocyte count), including 10% or more abnormal lymphocyte forms, and abnormalities in liver function tests. Specific diagnosis is by detection of antibodies. Molecular diagnostic procedures are also available. EBV can be cultured from the buffy coat—the layer of white blood cells that appears in centrifuged blood.
• Mumps


  An acute viral infection characterized by fever and swelling and tenderness of the salivary glands. Complications can include orchitis, oophoritis, meningitis, encephalitis, deafness, pancreatitis, arthritis, mastitis, nephritis, thyroiditis, and pericarditis.
• Use Droplet Precautions for patients with mumps.
• Reservoirs


  Infected humans
• Transmission


  Person to person by direct contact with saliva. Kissing facilitates spread among adolescents. EBV can be transmitted via blood transfusion.