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Chickenpox: VARICELLA-ZOSTER VIRUS (VZV) causes both chickenpox (varicella) and shingles (zoster). VZV is unusual fo ra herpes virus in that virtually all primary infections have signs and symptoms.The hallmark of all herpesviruses is establishment of permanent latency after primary infection. Rash often follows a dermatomal pattern. Respiratory infection initially. Lesions PRURITIC and often secondarily infected by bacteria. The virus infects through conjunctiva or respiratory tract mucosa and has a two-stage viremia: replicates in regional lymph nodes, primary viremia 4-6 days after infection. Humans are the ONLY known reservoir. Occurs in Winter-Spring. Respiratory secretion spread. Patient is most contagious 1-2 days before appearance of lesions and 4=5 days thereafter. Prodromal symptoms in older children and adults (fever, malaise, headache, myalgia, anorexia) are absent in younger children. Diagnosis: clinical findings are distinctive and normally sufficient. Secondary bacterial infections of lesions is common and may hinder recognition. Presence of MULTINUCLEATED GIANT CELLS. Aspirin is NOT recommended for 28 days (Reyes syndrome risk) Passive immunization possible with VZIG (Varicella-Zoster Immune Globulin) up to 3 days post exposure for high risk patients to prevent disease or modify disease course. Acyclovir is effective. A chicken pox vaccine is available (Varivax). In some kids when you inoculate them they get low grade measles case. "Oka" strain: had a kid that died from this. Theorized that if don't keep immune system challenged can get shingles.
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Fifth Disease: Complications include anemia and hydrous fetalis. Similar to EBV, which majority will have no problem, some will have anemia. If transfuse these pt's became generic chimerics. Pregnant: chimeric the mom and child.
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HHV6/Roseola/Exanthum Subitum/Roseola Infantum/6th disease: Infection is very prevalent, but unrecognized until a proper culture system was available. Cardinal signs: sequence of HIGH FEVER followed by a eruption of a rose-colored rash. Defervescnece is rapid and linked with the appearance of a maculopapular rash that involves the trunk and neck. HHV-6 infection complications are thought to be rare. Reservoir for infection is adult carriers. This virus is reactivated and shed in saliva of adults that are immune suppressed, suggesting that reactivation/shedding is the source for childhood infections. Herpes viruses ALL return. Lab of CHOICE: detection of antibody by EIA (Elisa Immunoabsorbant assay). DNA sequence detection by PCR amplification is powerful, but slow. Isolation of patients is probably unnecessary. No antiviral therapy required. ?No preventative measures.
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Parvovirus B19/Fifth Disease/Erythema Infectiosum: Prodromal illness of several days duration with mild symptoms; fever, headache, malaise, myalgia, respiratory symptoms, sometimes nausea, vomiting. Usually seen in elementary school aged kids. CHARACTERISTIC SLAPPED CHEEK APPEARANCE. Maculopapular rash and trunk. Rash on trunk is lacy. Circumoral fever->similar to scarlet fever, but NOT sand papery. CONNECTIVE TISSUE MANIFESTATIONS: wrists, knees. Many adults may have arthritis or arthralgia alone without any other preceding symptoms. This virus was accidentally discovered in lot B sample 19 of blood in asymptomatic donors. No latent stage is known for this virus. Parvovirus is the ONLY known human parvovirus capable of INDEPENDENTLY causing disease. Epidemics are noted as outbreaks of EI (Erythema Infectiosum) in schools. EI is most commonly recognized symptomatic illness caused by Parvovirus B19. Detection of anti B19 IgM.
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Pox Virus: Orthopoxovirus: a
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Pox Virus: Smallpox (variola): Two types: major and minor. This virus was eradicated in 1977. Never seen since. Lab stocks exist in case of emergency. It is vicious to the eyes. In contrast to chickenpox, a single crop of vesicles at the identical stage of development will appear in these patients. Smallpox was developed as a biological warfare agent. Monkeypox is an exocit rodent. Person-to-person transmission limited. Raised concerns that they monkeypox has potential to evolve or transform into smallpox. US government has 300 million vaccinations for smallpox just in case may need to produce vaccine against terrorist vaccine.
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Pox Viruses: Cowpox (Vaccina): Used by Jenner for original vaccination experiments. Benign in humans. Immunologic cross reaction. What we need is cowpox, NOT small pox for the vaccine. Terrorist have made a manipulated version that defeats original vaccine. We need small pox to make the small pox vaccine.
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Rubella/German Measles: MUCH LESS INFECTIOUS THAN MEASLES. Mild exanthematous disease in children and adults, devastating effects when occurring in utero. RESPIRATORY rout of INFECTION in contrast to other Togaviruses. This is the ONLY human virus that is NOT a vector and is respiratory. Close and prolonged contact probably needed for infection. Children often escape natural infection. Rubella was originally thought to be benign until Congenital Rubella Syndrome (CRS) recognition. Rubella infection early in pregnancy early creates a very substantial risk to fetus: CATARACTS, GLAUCOMA, HEARING LOSS, CNS involvement. The timing of rubella infection is critical element in outcome (early in pregnancy is worst): first month 50% risk of CRS. Vaccination has nearly eliminated congenital rubella syndrome in the US. Serological detection of antibody is most commonly employed: Anti-Rubella IgM. MMR vaccine is contraindicated during pregnancy due to a theoretical risk to fetus. Determine immune status of females at all opportunities such has marriage, prenatal visits, delivery.
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Rubeolla/Measles: Multinucleated giant cells. Allows for direct cell-to-cell infection. Prodromal stage: Cough, Coryza, Conjunctivitis. KOPLIK'S SPOTS on buccal mucousa is DIAGNOSTIC. These spots disappear 2 to 3 days after rash eruption. Rash presents last and spreads from head to toe. Resolution: rise in antibody titers, viremia stops. Atypical measles: occurs in patients who received the formalin-inactivated vaccine who were later exposed to mild type virus or newer generation vaccines. This has an abrupt onset, and is the MORE SEVERE form of measles. PNEUMONIA accounts for MOST MEASLES DEATHS. Other complications include diarrhea, encephalitis in a substantial number of measles patients (0.5% of all measles infections), SSPE (subacute sclerosing panencephalitis) which is now very rare in the US, but typically is a fatal complication. Immunologic abnormalities occur with acute infection. Measles is a PAROMYXOVIRUS that is indistinguishable from other paramyxoviruses. Has a LINEAR NON SEGMENTED GENOME. Uses H (hemagglutinin) for attachment and neuraminidase for fusing. Measles is rare in infants under 6 months due to maternal immunity. Has 2 to 3 year epidemic cycle. Measles an only be maintained by an unbroken chain of human infections. 500,000 or greater population needed to maintain an endemic disease. This agent is HIGHLY CONTAGIOUS. Respiratory tract entry and initial multiplication, followed by spread to LYMPHATIC system and viremia. Life long immunity to measles infection after natural infection. MOST IMPORTANT for DIAGNOSIS is FA: MULTINUCLEATED GIANT CELLS. Measles can be prevented by MMR vaccine or live attenuated measles virus (not given to immunocompromised or pregnant individuals). Measles outbreaks are linked to import of infection by unvaccinated air travelers-number of cases has reached a 15 year high. Vitamin A deficiency increases measles severity.
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Shingles: VARICELLA-ZOSTER VIRUS (VZV) causes both chickenpox (varicella) and shingles (zoster). Caused by a recrudescence of VZV. ABSOLUTE PREREQUISITE FOR SHINGLES IS PRIOR CASE OF VARICELLA (OR VACCINATION). Shingles lesions are PAINFUL. Pain may precede rash eruption by days to weeks. The rash is asymmetric. The rash has a unique dermatomal distribution. The term "zoster" refers to belt or stripe. 10% have involvement of the ophthalmic branch of the fifth cranial nerve, which can destroy the cornea. This is treated with acyclovir. Shingles is NOT directly infectious as such, but vesicles do contain VZV. Repeated bouts do not necessarily reveal immune incompetence. This disease is self-limited, but painful. Noe that VZIG does NOT and cannot prevent shingles. Zostavax vaccination REDUCES PAIN AND DURATION of shingles, but it is a preventative therapy and NOT used to treat shingles outbreaks or post herpetic neuralgia. Boosts VZV-specific immunity and avoids shingles in patients. Live, attenuated VZV vaccine preparation, much higher vaccine concentration than Varivax, not for use in children.
