Flashcards in 05 Viruses and Diseases Part 1 Duncan Deck (48)
What are the DNA viruses?
Poxvirus (smallpox). Herpes Virus. Adenovirus. Hepatitis B Virus. Papilomavirus
What viruses cause the common cold?
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?
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?
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