Flashcards in 06 Viruses and Diseases Part 2 Duncan Deck (55)
What are the two most common viruses causing diarrhea?
Rotavirus (<2 years of age). Norwalk virus (in older children and adults)
What are the general characteristics of Rotavirus?
It's a reovirus. Segmented, double-stranded RNA virus
What are the general characteristics of Norwalk Virus?
Small RNA calcivirus
What is the epidemiology of Rotavirus?
Primarily in the winter months. Asymptomatic to severe, fatal (severe dehydration). Infectious particles can remain for days on objects, for hours on hands (hygiene essential to prevent spread)
What is the pathogenesis of Rotavirus?
Primarily attacks and destroys intestinal cells. Vomiting a few days after infection. Diarrhea. Dehydration results
What is used as prevention from Rotavirus?
RotaTec given 3x prevents > 75% illnesses. It's a live, oral, pentavalent vaccine
What are the general features of Hepatitis Virus?
All of them infect liver cells - initial infection may be GI. Otherwise, they are very distinct types of viruses. Cause short acute illness, to persistent, latent, seemingly innocuous disease
What are the general characteristics of Hepatitis A Virus (HAV)?
Picornavirus (like polio, echo, coxsackie). Epidemiology: fecal-oral transmission (raw shellfish)
What is the pathogensis of Hepatitis A Virus?
Initially infects enteric mucosa. > 25 day latency. Elevated liver enzymes: AST, AlkPhos, LDH, Bilirubin. Liver pain, jaundice
What is the treatment for Hepatitis A Virus?
Passive immunization. Generally self-resolving
What are the general characteristics of Hepatitis B Virus (HBV)?
Hepadnavirus. DNA virus with VERY small genome (3000 bp, 4 genes). Unusual replication - involves reverse transcription (this is why it can cause cancer)
What is the epidemiology of Hepatitis B Virus?
Transferred via blood, body fluids (sex), needles. Initial acute infection, followed by extended latency. Hepatocellular carcinoma in later life. Very common in parts of Asia
What is the pathogenesis of Hepatitis B Virus?
Death of hepatic cells. Decreased cell mediated immunity. Jaundice. Fatigue, loss of appetite, dark urine. Cirrhosis of the liver, with long latency. Liver cancer, with long latency
What is the prevention and treatment of Hepatitis B Virus?
Passive immunization for acute infection. Vaccine is available. Interferon treatment. Various HIV agents: RT is common to both
What are the general characteristics of Hepatitis C Virus?
Flavivirus. Positive strand RNA virus 9.5kb in length. Newly recognized, poorly understood
What is the Epidemiology of Hepatitis C Virus?
Transferred via blood, body fluids (sex), needles (like HBV). Transfusion-mediated transfer was a major problem
What is the pathogenesis of Hepatitis C Virus?
Initial acute infection, followed by extended latency. Hepatocellular carcinoma in later life
What is the prevention and treatment of Hepatitis C Virus?
Screening of blood. No vaccine is currently available. Interferon alpha treatment (expensive, painful, only sometimes effective, but best alternative), combined with Ribavirin improves therapy
What are the general characteristics of Hepatitis D Virus?
Small, single-stranded RNA virus. Requires co-infection with HBV (lacks essential gene function, supplied in trans by HBV)
What is the pathogenesis of Hepatitis D Virus?
Increases the severity of HBV infection
What are the general characteristics of Hepatitis E Virus?
Single-stranded, positive sense, RNA virus. Related to the calciviruses. Fecal-oral transmission (like HAV). Rare in the US, prevalent in India
What are the general features of Herpes Viruses?
Large, enveloped, DOUBLE STRANDED DNA viruses. Cause a wide range of symptoms, from mild to severe. Cause short acute illness, leading to persistent, latent, infection. Herpes viruses include: VZV, Herpes Simplex, CMV, EBV
What is the epidemiology of Herpes Simplex Virus (HSV)?
Type 1: Spread by direct contact with secretions. Types 2: Spread from sexual contact. High incidence of Type 1 infection (most are asymptomatic, or cause only mild disease)
What are the clinical manifestations of Herpes Simplex Virus?
Genital lesions (much greater in HSV-II). Lesions above the waist: primarily HSV-I. Herpes meningitis: associated with HSV-I, and more severe, though rare, consequences
What is the prevention and treatment of Herpes Simplex Virus?
Several antiviral agents have good activity: Acyclovir, related agents like ganciclovir and penciclovir. Foscarnet
What are the general characteristics of Cytomegalovirus (CMV)?
Infected cells tend to enlarge, hence "cytomegalo". Most individuals have been infected, based on antibodies (mild infections). Pathogenicity principally an issue in immunocompromised. Low infectivity (greatest risk in CMV+ donor tissue, CMV- recipient). Treatment with ganciclovir
What are the general characteristics of Epstein-Barr Virus (EBV)?
Causes mononucleosis. Associated with certain cancers (rare). Most individuals have been infected, based on antibodies
What are the general characteristics of Herpes Virus Types 6 and 7?
Infect immune cells. Leads to lymphoproliferative disease. Most individuals have been infected by age 2, based on antibodies
What are the enteroviruses?
Poliovirus. Coxsackie virus. Echovirus