Rabies virus

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

Structure of Rabies Virus

抵抗力不强， 60C 30min 或 100C 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 4C 可持续 1 － 2 周。甘油中可保存数月。

Reservoir

Urban forms: Dogs and catsSylvatic forms: Bats, foxes, r

accoons, wolves, skunks, coyotes, mongooses, and biting animals

Transmission

By bite or scratch Via saliva Airborne ( bats)

BAT armadillo

Cat fox

raccoon dog

Rabies 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Headachemalaise 不适

Laboratory diagnosis

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

un-successful.

Transmission

contact infection sexual infection congenital infection.

Pathogenesis

Host-specific Tissue-specific.

Disease

Cutaneous warts Epidermodysplasia verruciformis Mucosal HPV infections

Cervical cancer and other cancers: A significant proportion of cancers is associated wi

th HPV infection: 11% of all cancers in women and 2% of all cancers in men.

LIFE CYCLE OF HUMAN

PAPILLOMAVIRUS

Laboratory diagnosis

- 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

shape

Human diseases associated with B19 parvovirus

Syndrome Host or condition Clinical features

Fifth diseases Children Adilts

Cutaneous rashArthralgia-arthrtis

Transient aplastic crisis

Underlying hemolysis Severe acute anemia

Pure red cell aplasia

Immunodeficiencies Chronic anemia

Hydrops fetails Fetus Fatal anemia

Fifth Disease

EPIDEMIOLOGY

These organisms are widely distributed in nature.

Enters the body through:

The respiratory tract

Blood transfusions

Vertically from mother.

Laboratory DIAGNOSIS

Laboratory diagnosis of acute parvo B19 is based on the presence of IgM antibodies. The virus cannot be cultivated in routine cell culture lines, but direct detection of the viral DNA may be achieved by PCR.

DIAGNOSIS

Prevention and Treatment

Immunological: no vaccines are available Treatment: Commercial immunoglobulin

preparations contain parvo B19 antibodies can successfully eliminate the infection in immunocompromised patients