Viral Zoonoses II Flashcards
What are characteristics of poxviruses?
BIG brick-shape particles
Complex (neither icosahedral nor helical)
Genome = double-stranded, linear DNA
Only DNA virus that replicates solely in the cytoplasm
Resistant to inactivation
What are the symptoms of smallpox?
Disfiguring disease with high mortality
Spread by secretions from mouth and nose and by material from pocks or scabs
Flesh colored pocks cover the body, mostly on the face and trunk
- also cover palms and soles of feet
What are the symptoms of Molluscum contagiosum infection?
Wart-like, 2-5mm papular lesions on the face, back, and buttocks
- mainly on children
Spread via towels in swimming pools and gymnasiums (direct contact)
Self-limiting after 4-6 months, but second attacks are common
What are symptoms of tanapox and yabapox?
Skin infection (fairly common) in Africa
Transmission from infected animals by contaminated arthropods
Infection begins with a fever and severe headache fro 3-4 days before 1-2 papular, but never pustular, lesions
Self limiting (5weeks)
What is an Orf lesion?
Vessicular lesion caused by a poxvirus of sheep or goats
cowpox and vaccinia can cause lesion as well
(often seen in farmers/taxidermists)
What is monkeypox?
Pox virus infection (vaccinia immunization is protective)
Serious (1-15% fatality)
Very rare
Reason for exotic animal control
Primary lesions may show dark ulceration and spread to secondary lesions
How is diagnosis of rabies made?
Staining the brain
- Direct Fluorescence antibody stains used
- H&E shows eosinophilic cytoplasmic inclusion bodies known as negri bodies
(aggragate of viral protein)
What are characteristics of SARS?
caused by SARS coronavirus
Symptoms of Acute Respiratory Distress Syndrome (ARDS)
Diagnosis should be considered only in patients who require hospitalization for radiographically confirmed pneumonia and who have epidemiologic history that raises suspicion
What are symptoms of arbovirus infections?
Flu-like symptoms - usually non-specific, resembling other viral illnesses such as influenza (fever, rash, aches, chills)
Encephalitis may occur in:
VEE/EEE/WEE
West nile
St. Louis encephalitis
California sero-group
Japanese encephalitis
How are arboviruses diagnosed?
Serology
Direct detection tests - assays for detection of antigen or nucleic acids are available
What are characteristics of West Nile Virus?
Arthropod borne flavivirus
+ sense RNA
Spread by Culex mosquito
What are important flaviviruses?
West Nile virus
Japanese encephalitis
Yellow fever
Dengue fever
What are symptoms of Japanese encephalitis?
Transmitted by Culex mosquitos
Most infections are subclinical
1 in 300 develop life-threatening encephalitis
Diagnosis by serology
What are characteristics of Yellow Fever?
A flavivirus
Occurs in two forms:
Jungle YF is the natural reservoir
- non-human primate/mosquito life cycle
human infection is incidental
Urban YF is transmitted between humans by Aedes aegypti mosquito
What are symptoms of Yellow Fever?
Chills
Fever
Headache
Generalized myalgias
GI complaints (N/V)
GI hemorrhage leads to “black vomit”
Liver involvement causes jaundice
50% mortality - no antiviral tx
Affective live attenuated vaccine
What are characteristics of Dengue?
Flavivirus
4 serotypes
Transmitted by Aedes mosquitos
Human infections arise from human-mosquito-human cycle
What are symptoms of Dengue?
High fever
lymphadenopathy
Myalgia
Bone and joint pain
headache
maculopapular rash
Severe cases may present with hemorrhagic fever and shock
Diagnosis made by serology
No nativiral therapy or vaccine available
What are the symptoms of the equine encephalitis viruses?
Flu-like symptoms may progress to encephalitis
Generally resolves w/o sequelae, but may result in:
paralysis
mental disorders
death
(togaviruses transmitted by insects)
What are characteristics of Colorado Tick Fever virus?
Reovirus
Icosahedral
Non-enveloped, dsRNA, 12 segments
Transmission: Wood tick
Infects erythroid precursor cells and persists
Serious hemorrhagic disease from infection of vascular endothelium
What are symptoms of Colorado Tick Fever?
Usually mild or subclinical
Symptoms of acute disease resemble dengue and include:
fever
chills
headache
myalgia
athralgia
photophobia
lethargy
