Pg 15 - 19 Flashcards
A general term used to indicate an infection of the liver caused by one of several major distinct viral agents. Symptoms, which vary in severity and are not specific to the causative agent, include: Anorexia and weight loss; Hepatic tenderness; Jaundice and dark urine.
Viral Hepatitis
NOTE: Hepatitis viruses are not taxonomically related to each other.
Surface Antigen (HBsAg)
Viral structure – Enveloped, DNA virus
Hepatitis B (HBV)
Core – DNA and DNA polymerase
• Hepatitis __ Core Antigen (HBcAg)
• Hepatitis __ “e” Antigen (HBeAg) (“e” antigen of the core) – presence is associated with relatively high infectivity
Hepatitis B (HBV)
Presence of what antigen for Hep B is associated with high infectivity?
“e” Antigen (HBeAg)
(a) Transmission - parenteral route most predominant mode. Contact with blood or blood products, usually via contaminated needles or syringes.
(b) High risk groups
• Intravenous drug users; male homosexuals
• Patients with multiple transfusions; Hemophiliacs; Dialysis
(c) Incubation period
• Usually 45 to 180 days
• Replicates in liver
Hepatitis B (HBV) transmission
Hepatitis B (HBV) transmission?
parenteral route most predominant mode (Contact with blood or blood products, usually via contaminated needles or syringes)
Hep B high risk groups?
IV drug users
male homosexuals
patients with multiple transfusions
hemophiliacs
dialysis
Important antigens for Hep B labwork?
HBsAg
HBeAg
Earliest marker of acute infection; indicates infectious state
• Persistence over 6 months implies chronic disease (failure to seroconvert to anti-HBs)
HBsAg (i.e. Hepatitis B Surface Antigen)
- Early indicator of acute infection, active virus replication, and most infectious period
- Persistence beyond 10 weeks indicative of progression to chronic carrier state and probable chronic liver damage
(Note that this isn’t the EARLIEST indicator)
HBeAg (core-associated “e” antigen)
- Seroconversion from HBeAg to anti-HBe usually occurs during late acute phase - suggests resolution of infection and lowering of transmissibility
- Chronic/carriers fail to seroconvert during acute phase
Anti-HBe (antibody to Hepatitis B “e” antigen of the core)
- Appears during convalescence – indicates recovery and immunity
- Major protective antibody against HBV (also develops from vaccination)
- Failure to seroconvert indicative of chronic infection
Anti-HBs (antibody to Hepatitis B surface antigen)
Acute Hep B infection - viral hepatitis that resolves within?
3-6 months
Hep B infection chronic/chronic carrier infection timelines?
May last for several months to decades with or without symptoms
Infection may progress with continued active secretion of HBsAg in the absence of apparent active viral replication
HBV vaccine?
Active, long term immunity (anti-HBs) (85-95% success)
As we see the Hep B antigens go down, we hope
the AB go up (active immune response, right?)
If Hep B antibody count goes up, and the HB antigens goes down,
we can assume the patient is in the process is being cured.
If antibody response (as can be seen in labwork) is not robust enough, the Hep B antigens will proliferate, likely leading to ____ infection
THINK ABOUT THE GRAPHS MENTIONED
chronic
Hep B is DNA virus, Hep C is?
RNA
Viral structure – Small, lipid-enveloped RNA virus
Transmission - parenteral route
Hepatitis C (HCV)
Disease state/stages very similar to Hepatitis B
(a) Accounts for 15-40% of community acquired hepatitis; increased in IV drug users;
(b) High co-infection with HIV
Hepatitis C (HCV)
REVIEW HEP B course of infection to refresh
Vaccine for Hep C?
Negative ghost rider (too many antigenic subtypes)
Structure – Small, nonenveloped, RNA virus – Capsid protein (HA Ag)
Hepatitis A – genus Hepatovirus
(a) Transmission – fecal-oral route (enteric route) (primarily via food and water)
(b) High risk groups: Institutionalized persons, Children in day care centers, World travelers, Military, Drug addicts
Hepatitis A – genus Hepatovirus
(a) Incubation period - 15 to 45 days
(b) Replicates within liver and small intestines
(c) Blood and feces are infectious during 2-6 week incubation and early illness period – No chronic state or carrier state
Hepatitis A – genus Hepatovirus
No chronic or carrier state?
Hepatitis A – genus Hepatovirus
Prophylaxis and treatment for Hep A?
Vaccine or immune serum globulin
(a) Bunyaviridae – Hantaviruses, Crimean-Congo Hemorrhagic Fever, Rift Valley Fever
(b) Filoviridae family - Ebola & Marburg
(c) Flaviviridae family - Dengue, Yellow Fever, West Nile, Zika, others
(d) Togaviridae family, Alphavirus genus - Chikungunya
Hemorrhagic Fever Viruses
(2) Contagious — MODERATE
(3) Incubation period 4-21 days
(4) Duration of illness: 5-16 days
(5) Mortality variable (10 to 90%)
Hemorrhagic Fever Viruses
Hemorrhagic fever viruses? (Common names)
Crimean-Congo Hemorrhagic Fever
Rift Valley Fever, Hantavirus
Ebola & Marburg
Dengue, Yellow Fever, West Nile, Zika, others
Chikungunya
(a) Moderately Frequent: Northern Asia, Europe (>150K/year; 2-40% mortality)
(b) Transmitted via inhaled rodent excreta
Hemorrhagic Fever with Renal Syndrome (HFRS) (Hantaan, Seoul, Puumula viruses)
(hantavirus)
(a) Very Infrequent: North America
(b) Transmitted via inhaled rodent excreta
Hantavirus Pulmonary Syndrome (HPS) (Sin Nombre virus)
(b) Transmitted via inhaled rodent excreta
Hemorrhagic Fever with Renal Syndrome (HFRS) (Hantaan, Seoul, Puumula viruses)
Hantavirus Pulmonary Syndrome (HPS) (Sin Nombre virus)
Fever, severe joint pain (“Breakbone Fever”), conjunctivitis, headache
Hemorrhagic fever form (lower frequency) – severe illness
(1) Frequent: Tropical & semi-tropical (50K-1M cases/year; DHF 3% mortality; very infrequent in USA)
(2) Transmitted by Mosquitoes
Dengue Virus; Dengue Hemorrhagic Fever – (4 types)
(1) Moderately Frequent: Tropical Africa, Amazon basin (200K cases/year; 30K deaths)
(2) Transmitted by Mosquitoes
Yellow Fever Virus
(1) Moderately Frequent: Africa, SE Asia, South & Central America (1M cases; 3K in W.Hemisphere, ~30 in USA; very low mortality)
(2) Transmitted by Mosquitoes
(3) Illness: Dengue-like symptoms; hemorrhagic form rare
Chikungunya virus
similar SSx to Dengue – hard to tell apart
(1) Zoonotic in Africa; Infrequent in humans
(2) Transmitted by mosquitoes
Rift Valley Fever virus (RVF)
(1) Infrequent: Africa, Middle East (to West China)
(2) Transmitted via ticks
Congo-Crimean Hemorrhagic Fever Virus (CCHF)
(1) Moderately Frequent: West Africa (300-500K cases, 5K deaths)
(2) Transmitted via rodent excreta (urine)
Lassa Fever Virus
(1) Infrequent: West & Central Africa (tens to thousands per year; ~35% deaths)
(2) Vector/reservoir
(a) Fruit bats & bush meat -> animals, human contact
(b) Transmission: direct contact with blood or body fluids
• At-Risk Areas: mucosal tissue, eyes, breaks in skin
• Aerosolization may deposit infectious droplets on at-risk tissues, but no aerosol transmission to respiratory tract
• Superspreaders: 3% of infected persons spread disease to 60+% of victims
(3) Incubation: up to 21 days (?)
(4) Contagious: from day of first symptoms (?) until no virus in blood (semen harbors for 3 months)
(5) Vaccine – in use in Africa (live Vesicular Stomatitis virus with gene for Ebola surface protein)
Ebola Hemorrhagic Fever virus (Marburg virus is similar)
(a) Sudden onset fever, intense weakness, muscle pain, headache, sore throat
(b) Vomiting, diarrhea, rash, internal & external bleeding
(c) Acute fever, Flu-like symptoms, muscle aches, rash/erythema/petechiae
(d) Hemorrhage / Capillary leakage (vascular permeability, abnormal blood clotting) -> Shock
Ebola Hemorrhagic Fever virus (Marburg virus is similar)
Differentiate Ebola from?
Malaria, Lassa Fever Virus, Typhoid, other VHF
What type of long-term effects would you expect to see from an Ebola survivor?
chronic fatigue, headache, muscle/joint pain, memory loss, eye pain/blurry vision/sensitivity, hearing loss
