Pg 19 - 25 Flashcards by Cal Schiller

(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)

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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

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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%

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Encephalitis (inflammation of the brain) & meningitis (inflammation of the me`ninges membrane)

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Many of the viral encephalitises are diagnosed how?

SSx & geography, primarily.

Immunodiagnostic and PCRs can be options

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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

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Predominant viral encephalitis in USA?

West Nile Virus

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Fever, rash, joint pain – usually mild or asymptomatic

Conjunctivitis, headache – possibly Guillain-Barre’ Syndrome

Zika Virus

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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

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Both are similar and somewhat predominant in USA?

Variants of Japanese Encephalitis

St Louis & La Crosse encephalitis viruses

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(From Africa 1940s) Asia & S.Pacific, to Brazil 2014?; to Americas in 2015-2016

Zika virus

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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

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Similar to Equine Encephalitis but in Europe?

Tick-borne encephalitis virus

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Encephalitis in Australia?

Murray Valley Fever

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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

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(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

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Rabies virus

Rabies travels through what system(s)?

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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

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Clinical manifestations of rabies

Death often due to respiratory paralysis

Encephalomyelitis (almost always fatal once symptoms appear)

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Rabies

DNA virus – Over 170 antigenic types; more than 40 are sexually transmitted

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Human Papilloma Virus (HPV)

Causes genital warts – HPV types 6 and 11 – Vaccine (2006)

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Human Papilloma Virus (HPV)

Causes various types of skin warts

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Human Papilloma Virus (HPV)

e.g. Coxsackie, Polio, Echo, Enterovirus

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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.

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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

Pg 19 - 25 Flashcards

(39 cards)