Transcript Rabies virus

Rabies virus
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Shape: bullet
Genome: -ssRNA
enveloped virus
CPE: Negri body
Structure of Rabies Virus
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抵抗力不强，60C 30min或100C
2min可灭活。可被强酸、强碱、乙醇、
乙醚、肥皂水、去垢剂等灭活。
在脑组织中室温或4C可持续1－2周。
甘油中可保存数月。
Reservoir
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Urban forms: Dogs and
cats
Sylvatic forms: Bats, foxes,
raccoons莞熊, wolves,
skunks臭鼬, coyotes丛林狼,
mongooses猫鼬, and biting
animals
Transmission
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By bite or scratch
Via saliva
Airborne ( bats)
BAT
armadillo
Cat
raccoon
fox
dog
Rabies or hydrophobia
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Fever
Dysphagia咽下困难
Altered mental
status
Excitement,
agitation
Paralysis麻痹
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Hydrophobia恐水
Hypersalivation
多涎
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Nausea,
vomiting恶心;作
呕
Headache
malaise不适
Laboratory diagnosis
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Diseased dog: viral antigen and
Negri body in brain tissue.
Patient: IF assay, PCR.
Prevention and treatment
Prevention and treatment
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Bite Geographical area, type of animal,
severity and site of bite.
Animal
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Live - observe in cage:
If survives > 8 days, then NOT rabies.
Dead - brain
- Negri bodies
- IFA
- virus isolation
Prevention and treatment
Man
Live - difficult diagnosis
- clinical picture, skin biopsy, corneal
impression (antibodies only appear
very late)
Dead - brain sent to Onderstepoort
"Negri bodies" in cytoplasm of brain
cells; immunofluorescence virus
isolation .
Human papillomavirus
(HPV)
Biological properties
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naked dsDNA virus
with 9 ORF
belongs to
Papovaviridae
more than 60 types
artificial
cultivation unsuccessful.
Transmission
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contact infection
sexual infection
congenital infection.
Pathogenesis
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Host-specific
Tissue-specific.
Disease
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Cutaneous warts
Epidermodysplasia verruciformis
Mucosal HPV infections
 Cervical cancer and other cancers:
A significant proportion of cancers is
associated with HPV infection: 11% of all
cancers in women and 2% of all cancers in
men.
LIFE CYCLE OF HUMAN
PAPILLOMAVIRUS
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Laboratory diagnosis
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- Cytology
- Histology
- Colposcopy in the case of genital HPV
infections.
- Electron microscopy.
- Immunocytochemistry can detect major
capsid protein but are generally group
specific not type specific
- DNA detection techniques. This is the
only way to type HPVs.PCR
PARVOVIRUSES
Human parvovirus B19
DISTINCTIVE PROPERTIES
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Are small, naked viruses with
icosahedral nucleocapsids.
Contain single-stranded DNA
and replicate in the nucleus.
Include human parvovirus (B19)
and adenoassociated virus, a
defective virus of the
dependovirus genus that
requires adenovirus to replicate.
Human pathogen, B19, has
tropism for red blood cell
progenitors
Human diseases associated with B19
parvovirus
Syndrome
Host or condition
Clinical features
Fifth diseases
Children
Adilts
Cutaneous rash
Arthralgiaarthrtis
Transient
aplastic crisis
Pure red cell
aplasia
Underlying
Severe acute
hemolysis
anemia
Immunodeficienci Chronic anemia
es
Hydrops
fetails
Fetus
Fatal anemia
EPIDEMIOLOGY
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These organisms are widely
distributed in nature.
Enters the body through:
The respiratory tract
Blood transfusions
Vertically from mother.
DIAGNOSIS
PARVOVIRUS B-19 SEROLOGY
Serology
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Direct detection of the
viral DNA may be achieved
by PCR
Interpretation
IgGIgM-
No past infection
Patients susceptible to
infection
IgG+
IgM-
There has been a past
infection
Patient probably immune
IgG + or –
IgM
equivocal
Current or recent infection
Patient should be retested
in a few weeks
IgG+
IgM+
Ongoing or recent infection
Fetus may be at risk if
patient pregnant
IgG- (or
equivocal)
IgM+
Current infection
Patient should be retested
in a few weeks
Prevention and Treatment
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Immunological: no vaccines are
available
Treatment: Commercial
immunoglobulin preparations
contain parvo B19 antibodies can
successfully eliminate the
infection in immunocompromised
patients