病毒感染的诊断和防治原则 英文Viral infection diagnosis prevention antiviral

• An observable morphologic changes which take place in the host cells as a result of virus replication
– Rounding, detachment – Shrinkage – Increased refractivity (折射） – Aggregation – Cell lysis
II. Serology is the method of choice when the virus is no longer likely to be present or cannot be cultured.
III. Direct detection provides clinically relevant information in a minimum amount of time. The approach can be both highly sensitive and specific.
What types of specimens are collected to diagnose?
• Respiratory tract infections: –Nasal and
bronchial washings, –throat and nasal swabs, – sputum
• Eye infections:
meningitis cases:
infections:
– cerebrospinal fluid (CSF),
– urine
– blood
• Bloodborne infections:
• Genital infections:
– blood
– vesicle fluid or
swab
Diagnostic Methods in Virology
I. Virus isolation
Virus isolation
• Isolation is considered the “gold standard,” but not all viruses grow well or at all in currently available culture systems. .
• Viruses can be grown in: – Tissue (cell) cultures – Embryonated eggs – Animals
Laminar Flow Hoods
• Virologist’s facility • Laminar vertical flow
hoods – Contains HEPA
Problems with cell culture
Long period (may up to 4 weeks) required for result.
Many viruses will not grow in cell culture e.g. Hepatitis B virus, parvovirus (细小病毒), papillomavirus.
filter – Removes 99.97%
of particles of 0.3μM or higher
Figure 5-3: Vertical laminar flow hood.
Cell culture
Cell culture flask
Monolayer cell
Cytopathic Effects (CPE)
I. Virus Isolation II. Serology III. Direct Examination
Microscopic identification Detection of viral antigens Detection of viral nucleic acids
I. Isolation is considered the “gold standard,” but not all viruses grow well or at all in currently available culture systems.
– Syncytia（合胞体）, fusion of cells
– Inclusion body
Adenovirus CPE
uninfected early infection late infection
respiratory syncytial virus， CPE
uninfected
syncytia
➢Collect the samples according to the infection sitቤተ መጻሕፍቲ ባይዱs
➢Avoid contamination ➢Store and transport the samples in low
temperature (4℃,dry ice, liquid nitrogen)
• Gastrointestinal tract infections:
– stool and rectal swabs
• Vesicular rash:
– vesicle fluid,
– skin scrapings
– throat and conjunctival swab/scraping
• Encephalitis and • Urinary tract
Part I. Laboratory diagnosis of viral infections
Collection and transportation of specimens
Quality of patient specimens and their transport to the laboratory is important.
Principles of laboratory diagnosis, prevention and antiviral agents
Liu Dongying
Outline
Part I. Laboratory diagnosis of viral infections
Part II. Prevention of viral infections Part III. Antiviral agents