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Rabies virus


   

Shape: bullet Genome: -ssRNA enveloped virus CPE: Negri body


Structure of Rabies Virus


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 

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   

By bite or scratch Via saliva Airborne ( bats)


BAT

armadillo


Cat

raccoon

fox

dog


R abies or hydrophobia   

Fever Dysphagia 咽下困难 Altered mental status Excitement, agitation Paralysis 麻痹

Hydrophobia 恐水  Hypersalivation 

多涎

Nausea, vomiting 恶心 ; 作呕  Headache  malaise 不适 


Laboratory diagnosis ď Ž

ď Ž

Diseased dog: viral antigen and Negri body in brain tissue. Patient: IF assay, PCR.


Prevention and treatment


Prevention and treatment 

Bite Geographical area, type of animal, severity and site of bite.

Animal

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 

 

naked dsDNA virus with 9 ORF belongs to Papovaviridae more than 60 types artificial cultivation unsuccessful.


Transmission   

contact infection sexual infection congenital infection.


Pathogenesis ď Ž ď Ž

Host-specific Tissue-specific.


Disease   

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 яБо


Laboratory diagnosis ď Ž

ď Ž

- 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 

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 Fifth diseases

Transient aplastic crisis Pure red cell aplasia Hydrops fetails

Host or condition Children Adilts

Clinical features Cutaneous rash Arthralgiaarthrtis Underlying Severe acute hemolysis anemia Immunodeficienci Chronic anemia es Fetus Fatal anemia


EPIDEMIOLOGY 

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

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 ď Ž

ď Ž

Immunological: no vaccines are available Treatment: Commercial immunoglobulin preparations contain parvo B19 antibodies can successfully eliminate the infection in immunocompromised patients

Rabies virus  
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