Pg 19 - 25 Flashcards
(1) Bunyaviridae – La Crosse EV
(2) Flaviviridae – West Nile, Zika, St.Louis EV, Japanese EV, Tick-Borne EV
(3) Togaviridae family, Alphavirus genus – Eastern/Western/Venezuelan Equine Encephalitis virus
Etiologic Agents are RNA viruses (“encephalitis” is in the name of most)
Viral encephalitis Transmission - Mosquito from animal to human, except
(1) Zika - Transmitted by mosquitos & Semen – 20% of infected become ill
(2) Tick Borne Encephalitis Virus (TBE) is transmitted by ticks
Disease:
(1) Travels bloodstream to CNS & other organs
(2) Encephalitis (inflammation of the brain) & meningitis (inflammation of the meninges membrane)
(3) Treatment is very limited or non-existent; vaccines usually non-existent
(4) Mortality rate often 20-40%
(1) Bunyaviridae – La Crosse EV
(2) Flaviviridae – West Nile, Zika, St.Louis EV, Japanese EV, Tick-Borne EV
(3) Togaviridae family, Alphavirus genus – Eastern/Western/Venezuelan Equine Encephalitis virus
(1) Bunyaviridae – La Crosse EV
(2) Flaviviridae – West Nile, Zika, St.Louis EV, Japanese EV, Tick-Borne EV
(3) Togaviridae family, Alphavirus genus – Eastern/Western/Venezuelan Equine Encephalitis virus
Encephalitis (inflammation of the brain) & meningitis (inflammation of the me`ninges membrane)
Many of the viral encephalitises are diagnosed how?
SSx & geography, primarily.
Immunodiagnostic and PCRs can be options
- Peaks late summer-early fall
- Cases (USA): ~50K illness (>3M infected?); ~2200 deaths
- Neuroinvasive (23K)
Found in Africa, India, Middle East, Europe, USA
West Nile Virus
FREQUENT encephalitis
Predominant viral encephalitis in USA?
West Nile Virus
Fever, rash, joint pain – usually mild or asymptomatic
- Conjunctivitis, headache – possibly Guillain-Barre’ Syndrome
Zika Virus
- Travels via blood to fetus; causes microcephaly and other damage
- Cases vary dramatically – 5 to 5000 per year
(No longer a global emergency)
Zika Virus
Both are similar and somewhat predominant in USA?
Variants of Japanese Encephalitis
St Louis & La Crosse encephalitis viruses
(From Africa 1940s) Asia & S.Pacific, to Brazil 2014?; to Americas in 2015-2016
Zika virus
Biological threat agent
10 to 20 cases per year USA; ~30% mortality
SE USA, C. America, Northern S. America
E/W/Venezualan Equine Encephalitis Viruses
Similar to Equine Encephalitis but in Europe?
Tick-borne encephalitis virus
Encephalitis in Australia?
Murray Valley Fever
Transmitted by virus-laden saliva of a rabid animal introduced into a bite or scratch (Most prevalent infected animals: coyotes, foxes, skunks, raccoons, bats, cats, dogs – geographical locations vary)
Rabies virus
genus Lyssavirus, family Rhabdoviridae – RNA virus
(1) Incubation period – Usually about 8 weeks (depends on site of inoculation)
(2) Virus replicates in tissue at bite site
(3) Virus replicates in and travels in peripheral nerve system
Rabies virus
Rabies travels through what system(s)?
Initially proliferates in the Peripheral Nervous System which it uses as a conduit for movement into the Central Nervous.
Infects brain, affecting the eyes, salivary glands, skin and other organs
(1) Infects brain and affects eye, salivary glands, skin, & other organs
(2) Encephalomyelitis (almost always fatal once symptoms appear)
(3) Headache, fever, malaise; a sense of apprehension; spasms of muscles used in swallowing; delirium and convulsions
(4) Death often due to respiratory paralysis
Clinical manifestations of rabies
Death often due to respiratory paralysis
Encephalomyelitis (almost always fatal once symptoms appear)
Rabies
DNA virus – Over 170 antigenic types; more than 40 are sexually transmitted
Human Papilloma Virus (HPV)
Causes genital warts – HPV types 6 and 11 – Vaccine (2006)
Human Papilloma Virus (HPV)
Causes various types of skin warts
Human Papilloma Virus (HPV)
e.g. Coxsackie, Polio, Echo, Enterovirus
Enterovirus
(1) RNA virus, small, non-enveloped; stable over wide pH and temperature range
(2) Multiple antigenic types, formerly known as (genus names): Coxsackie, Poliovirus, Echo, & Enterovirus
(3) Transmission: Fecal to oral, respiratory secretions, contact with vesicle fluid
b.
Enterovirus (genus)
causes various antigenic types cause several diseases (e.g. myocarditis, pleurodynia, vesicular rash)
Coxsackie
RNA virus, small, non-enveloped
(enterovirus)
Severe cases might require a heart transplant/artificial heart?
Coxsackie
myocarditis, pleurodynia, vesicular rash
Coxsackie
RNA virus – Genus Morbillivirus, member of Paramyxovirus family
Transmitted person-to-person by contact with respiratory secretions, e.g. cough, sneeze, droplets on surfaces. Highly contagious
Measles virus
(1) Symptoms –cough, rhinitis, high fever, red eyes, macropapular rash (3-5 days after start of symptoms)
(2) Symptoms occur about 10-12 days after exposure and last 7-10 days
(3) Contagious from about 4 days prior to 4 days after start of symptoms or rash
M-SMPA-503-8-1
Oct 2019
23
(4) Secondary complications (30%), esp. diarrhea, blindness, inflammation of brain, pneumonia
Measles (Rubeola; red measles)
re-emergence, serious infection
Measles ssx and timelines?
Cough, high fever, red eyes, macropapular rash
Symptoms occur about 10 days after exposure and last for a week or so
CAN BE INFECTIOUS DAYS BEFORE AND AFTER SSX ARRIVE AND RETREAT
Secondary complications (30%), esp. diarrhea, blindness, inflammation of brain, pneumonia?1
measles
(1) Symptoms – fever, muscle pain, headache, fatigue, usually followed by swelling of parotid glands (may be confused with swelling of lymph nodes)
(2) Symptoms occur about 16-18 days after exposure and resolve after 4-10 days
(3) Contagious from a few days prior to about 4 days after symptoms
(4) Complications include meningitis, pancreatitis, permanent deafness, testicular/ovarian swelling. Symptoms in adults more severe than in children
Mumps virus
a. DNA poxvirus
b. Causes mucous membrane lesions or “water warts” on the skin; most commonly on face, trunk, arms, legs
c. Transmitted by touching the affected skin
Molluscum contagiosum virus (MCV)
a. DNA virus – Member of Orthopox family (e.g. monkeypox, camelpox, etc); not related to Chicken Pox
b. Disease – Smallpox
Variola major virus
(1) Synchronous progression: rash – macules vesicles pustules scabs
(a) Begins on face, hands, forearms, and spreads to lower extremities in 7-16 days
(b) Lesions on palms of hands and soles of feet and in mouth
Disease – Smallpox
Variola major virus
(3) Spread by aerosolized virus in droplets and powdered scabs
(4) Rapidly inactivated by UV light & disinfectants
Disease – Smallpox
Variola major virus
Smallpox disease details/progression?
Synchronous progression
rash->macules->vesicles->pustules->scabs
Starts on face/hands/forearms, moves to lower extremities
Lesions on palms/feet/mouth
(a) Vesicles or pustules - Scrape the base of the vesicle or pustule & make a touch prep on a microscope slide.
(b) Scab lesions - Remove as many scabs as possible (place in screw-capped plastic tube)
Laboratory diagnosis of smallpox/variola major
What should you rule out when concerned about smallpox?
Varicella-Zoster virus
(also consider other “pox” viruses)
Variola-specific tests
