virus Flashcards
virus in the community?
Virus infections in the community:…..what‘s important and what not?..
Age - Childhood infections with exanthema
Measles virus Measles (SSPE)
HHV-6 or HHV-7 Exanthema subitum
Entero virus hand- foot and mouth disease (fetal death)
Varicella zoster virus chickenpox
Parvovirus B19 fifth disease (fetal hydrops)
Rubella virus ‚German‘ measles (embryopathy)
Infections of the airways
Gastroenteritis
• Rota virus, Adeno viruses, Astro viruses, Calici viruses
Meningitis, encephalitis, spinal paralysis
• Enterovirus, Tick borne encephalitis, Rhabdoviruses, Measlesvirus,
Herpes simplex and Varicella Zoster virus, Polio virus
Infections of the eye
• Adenoviruses, Coxsackie virus, HSV, VZV
Infections of the airways:
• Rhino virus, Parainfluenza virus, Respiratory-Syncytial-Virus (RSV),
Adenoviruses, Influenza virus, Cytomegalovirus (embryopathy)
Infections of the liver and immune cells, cancerviruses
• Hepatitis A, B(D), C, E HIV, Epstein Barr virus
gp vs hopsital requirements
- Laboratory diagnosis of viral infections (clinical virology), and outbreak
investigation (phylogeny/ index cases): - Preanalysis: clinical sample requisition/ advice, transport and sample
intake. Barcoded sample registration and database software. - Analysis: analytical methods in clinical virology including automated
systems. Serology-MEIA; real time PCR: Cobas amplicor, lightcycler,
virus culture methods - qualitative and quantitative; antigen test,
hemagglutination assays. Electronic transfer of results from automated
systems. - Concepts of specificity, sensitivity, selectivity, IT and human error.
Statistical significance/ test repeats. - Virological test interpretation and database software; generation of test
reports. - Technical and medical quality control; validation and authorization.
- Diagnosis/ differential diagnosis/ relevance: validation of by multiple
method confirmation. - Consulting in clinical virology; clinical rounds, staff management
- Governance issues: local trust policy.
range of virology methods?
- Life virus culture in eucaryotic cells or laboratory animals (gold standard:
strain collections, growth of virus for vaccines, eg flu vaccine). Neclected in
many health care systems, because of COST (skilled personal) and lack of
immediate relevance for diagnosis (time scale up to 3 weeks). Open
system: if virus grows, no need to know ID prior to test. Chance for new
pathogen detection. Only proof of detection acc. to Koch‘s postulates.
All other systems are closed systems: need to know what to look for. - Visualization by electron microscopy. Obsolete. Many hospitals do not
have instruments (COST). Requirement for 10e6 particles for detection (only
GI viruses and virus from skin lesions), no ID other than morphology. - Serology to detect immune responses. First method available for large
scale screening. Indirect, no pathogen detection and limited ID (cross
reactivity). Delay of serological response, 1 to 2 weeks. Limited diagnostic
value. Potential for automation - Rel. INEXPENSIVE - Molecular (nucleic acid) detection (NAD) methods, protein antigen by
antigen ELISA and detection of nucleic acids by PCR (real time). No
detection of life agents, ´debris‘ of cleared infection will also pick up. No
proof of infection. Half/open: new pathogens detectable by random PCR and
array chips (eg VIROCHIP/ Airborne lecture). Potential for automation rel.
EXPENSIVE
Chicken egg vaccine?
Chicken egg vaccine (Pandemrix®- Glaxo), vero cell vaccine (Celvapan®-Baxter)
symptoms of measles?
Symptoms
● Enanthema (Koplik-spots)
● Fever, laryngitis, tracheobronchitis
● makulopapulous exanthema
● Measles virus induces
immunosuppression
koplik spots
measles diagnosis?
wildtype CPE in B95 a cells
Serology (IgM- IgG) & RT-PCR possible but rarely necessary.
Generation of cell fusion (B95a, Vero):
giant multinucleated cells (= syncytia)
after measlesvirus infection
blood borne?
Bloodborne: ╬ Hepatitis B virus Vacc.- / lamivudine
╬ Hepatitis C virus - / interferon ααα
╬ HIV - / ++ antivirals
maculopapillary exanthema (primary HIV infection)
oral candidiasis
kaposis sarcoma
CMv retinitis
HIV?
HIV in T lymp, syncytia forming isolate
and it takes weeks to grow HIV: ..here syncytia of a T-lymphotropic strain
T lymphocytes are difficult to keep in culture
● need primary cells from Duffy coats
● need IL2 to maintain growth…
HIB lab diagnostic test?
- Screening test: Antibody-ELISA
99% sensitive, 95 bis 99% specific
detects human antibodies against all subtypes - Positive ELISA must be repeated
- Western Blot to confirm ELISA
detection of virus protein-specific antibodies
direct contact and ingestion?
● Direct contact ╬ Polio virus (!) Vacc.- / -
and ingestion: Calici viruses (!) - / -
Hepatitis A virus (!) Vacc.- / -
Cytomegalo virus - / ganciclovir
Adenovirus (eye) Isol.- / -
Herpes simplex (?) - / aciclovir
poliovirus lab diagnosis?
progress of CPE in HeLa cells
by enders, john franklin
how to diagnose virus infection?
