05 Viruses and Diseases Part 1 Duncan Flashcards
What are the DNA viruses?
Poxvirus (smallpox). Herpes Virus. Adenovirus. Hepatitis B Virus. Papilomavirus
What viruses cause the common cold?
Rhinovirus. Coronavirus
What are some general characteristics of respiratory infections caused by viruses?
Frequently occur because of bacterial superinfection. Typically, short incubation period. Spread by infectious droplets (fomites)
What is Orthomyxovirus?
Influenza virus
What are the surface proteins associated with influenza virus?
Hemagglutinin: attachment to cells. Neuraminidase: cell detachment
What is Antigenic drift?
Small changes in cell surface proteins caused by one or a few point mutations
What is Antigenic shift?
Large changes in cell surface proteins caused by recombination between different flu types (e.g. H2N1 –> H3N1 in flu virus)
What is the pathogenesis of the Influenza Virus?
Infection of respiratory epithelial cells. Cell function impaired. Immune response compromised. Interferon response. CTL response
What are the clinical manifestations from Influenza Virus?
Fever. HA. Muscle aches. Chills. Coughing
What does the Respiratory Syncytial Virus cause?
Single most important cause of viral respiratory disease in infants under 1 year old - almost everyone has been infected by age 2, but usually with no adverse consequences
What are the characteristics of Respiratory Syncytial Virus?
Paramyxovirus. Single-Stranded, non-segmented, negative strand RNA. Surface proteins: G protein, F protein
What is the epidemiology of Respiratory Syncytial Virus?
Annually, in fall and winter. Affects a significant proportion of kids. Lasts 5-7 days. Spread by older siblings
What is the pathogenesis of Respiratory Syncytial Virus?
Bronchiolar and alveolar inflammation. Bronchiolar and alveolar necrosis
What are the clinical manifestations of Respiratory Syncytial Virus?
Fever. Runny nose. Cough. Wheezing, sometimes
What is the prevention and treatment for Respiratory Syncytial Virus?
Supervision. Hygiene. Prophylactic passive immunity - for babies with elevated risk of RSV with severe consequences. Synagis (palivizumab): humanized mouse monoclonal antibody: treatment for premature infants (< 36 weeks) with underdeveloped immunse systems. Treatment of children with congenital heart disease or chronic lung disease as well. Ribavirin (or IgG + Ribavirin) can be used in immunocompromised infants
What are the general characteristics of Adenovirus?
Over 49 different infectious types. DOUBLE-STRANDED DNA virus. Infects infants predominantly. Can become latent in tonsil or adenoids. In many instances there is no obvious infection
What is the pathogenesis of Adenovirus?
Epithelial cell inflammation. Epithelial cell necrosis
What are the clinical manifestations of Adenovirus?
Respiratory distress (cold-like symptoms, to pneumonia)
What is the prevention and treatment for Adenovirus?
No specific therapy. Vaccines, but of questionable value
What are the general characteristics of Parainfluenza Virus?
Paramyxovirus. Single-Stranded, non-segmented, negative strand RNA. Four subtypes. Hemagglutinin surface protein targets human cell receptor. Neuraminidase
What is Type 1 Parainfluenza Virus?
Crop (young), pharyngitis
What is Type 2 Parainfluenza Virus?
Severe lower respiratory disease. Significant cause of severe respiratory disease in the young
What are the general characteristics of Rhinovirus?
Over 100 different infectious types. Picornavirus (same family as poliovirus). Single-stranded, positive sense RNA virus
What do Rhinovirus cells need to attach to in order to infect bronchial cells?
ICAM-1
What is the prevention and treatment for Rhinovirus?
“No” specific therapy. Pemciclovir - binds to surface, prevents virus-cell interaction
What are the general characteristics of Coronavirus?
Minor cause of the common cold - 5-10% of cases. Single-Stranded, positive sense RNA virus. Receptor - ICAM (same as rhinovirus). Mild upper respiratory distress. No specific therapy available. SARS-causing Coronavirus: high [mortality/infection] ratio
What are the general characteristics of Varicella-Zoster Virus?
Herpevirus. Large, double-stranded, DNA virus. Causes chicken pox in kids, shingles in adults. Following childhood infection, virus becomes latent in neurons (latency can persist into old age - Shingles)
What is the epidemiology of Varicella-Zoster Virus?
Most prevalent in late winter to spring. 95% untreated children will get chicken pox. Highly infectious (contagious from 1-2 days pre-rash until all form scabs. Incubation period preceding overt rash: 10-20 days)
What are the clinical manifestations of Varicella-Zoster Virus?
Itchy rash (a few lesions, to hundreds). Blisters, which dry, and scab over, lasting 4-5 days. Fever. Malaise
What is the prevention and treatment of Varicella-Zoster Virus?
Vaccine: a highly effective one is available (Varivax): vaccination is recommended for all kids between 12-18 months. Chemotherapeutics (primarily for immunocompromised): Acyclovir or Immunge globulin (from Ab-producing individuals)
What are the general characteristics of the Measles Virus?
Paramyxovirus. Single-stranded, negative sense, RNA virus. Surface proteins: Hemagglutinin, F protein. Causes rash in kids
What is the epidemiology of Measles Virus?
Affects primarily children. Highly infectious (contagious from 1-2 days pre-rash until all form scabs. Incubation period preceding overt rash: 10-14 days). Top 10 viral killer of youths worldwide
What are the clinical manifestations of Measles Virus?
Initially: Fever, cough, conjunctivitis, sore throat, HAs. Later (2-4 days): Macular, morbilliform rash, Koplik’s spots in mouth. Immunosuppression
What are the long term consequences of the Measles Virus?
Encephalitis. Neurologic damage. CNS infection leading to (2-10 years later) subacute sclerosing panencephalitis (very rare)
What is the prevention and treatment for Measles Virus?
Vaccine (highly effective: MMR) for all kids 12-18 months. Chemotherapeutics: Immune globulin, from Ab-producing individuals (primarily for immunocompromised)
What are the general characteristics of Rubella Virus (German Measles)?
Togavirus. Single-stranded, positive sense, RNA virus. Causes German, or 3 day, measles
What is the epidemiology of Rubella Virus?
Common in childhood. Only 30-60% infected kids develop detectable illness
What is the pathogenesis of Rubella Virus?
First targets upper respiratory tract. Then spreads to distant sites. Disease is mild, non-specific. Maculopapular rash, lasts for ~48 hrs. Fetal infection occurs, with potentially severe consequences
What is the prevention and treatment of Rubella Virus?
Vaccine (highly effective: MMR) all kids 12-18 months. No specific (chemo-) therapy
What are the general characteristics of the Mumps Virus?
Paramyxovirus. Single-stranded, negative sense, RNA virus. Surface proteins: Hemagglutinin, Neuraminidase
What is the epidemiology of Mumps Virus?
Most common age of infection: 5-15 years of age. 30-40% infected kids do not develop detectable illness
What is the pathogenesis of Mumps Virus?
First targets upper respiratory tract. Then spreads to salivary glands; also kidneys. Can include rash. Potential complications (meningitis, encephalitis, nerve and spine infection). In adult males, orchitis can result
What is the prevention and treatment of Mumps Virus?
Vaccine (highly effective: MMR) for all kids 12-18 months. No specific (chemo-) therapy
What are the general characteristics of Parvovirus B19?
Parvovirus. Single-stranded DNA virus (+ and - strands). Cause of “fifth” disease. “Slapped cheek” rash
What is the epidemiology of Parvovirus B19?
Common in young: 5-15 years old. Mild to undetectable illness
What is the Pathogenesis of Parvovirus B19?
Initially targets hematopoietic lineage cells (receptor: erythrocyte P antigen). Slapped cheek skin rash. Lacy reticular rash on trunk
What are the potential complications of Parvovirus B19?
Maternal: fetal transmission leading to fetal death. Infrequent: medical oversight to monitor
What is the prevention and treatment of Parvovirus B19?
No vaccine available (rarely necessary). No chemotherapy regimens characterized
