Rabies virus
Shape: bullet Genome: -ssRNA enveloped virus CPE: Negri body shape
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。
Reservoir Urban forms: Dogs and cats Sylvatic forms: Bats, foxes, raccoons, wolves, skunks, coyotes, mongooses, and biting animals
Transmission By bite or scratch Via saliva Airborne ( bats)
BAT armadillo
Cat fox dog raccoon
Rabies or hydrophobia Hydrophobia恐水 Hypersalivation多涎 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 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.
Cervical cancer and other cancers: 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
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 rash Arthralgia-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