Page 107 - MNU-PM503 Parasitology practical book

Pharm D- Clinical Pharmacy Program Third Level Parasitology and virology (PM501)

Diagnostic Methods in Virology

Diagnostic virology is concerned with identifying the virus associated with clinical

signs and symptoms.

Procedures most commonly used include:

1- Indirect Examination: Isolation and identification of the agent (cell culture

or fertile eggs).

2- Serology: Detection of a meaningful immune response to the virus

(antibody or cell-mediated) by immunologic assay(s).

3- Direct Examination: Identification of the agent by staining of specimens

or sections of tissue (light and electron microscopy) or detection of viral

nucleic acid (probes or amplification).

1- Indirect Examination:

Virus Isolation

• The first step in identification of a viral infection often involves the ability to

isolate the virus.

• For successful virus isolation in cell culture, the following steps are followed:

1. Care must be given to maintaining a cold chain at 4°C from the patient to the

laboratory, but with care not to freeze the sample as some viruses are labile to

freezing.

2. Samples may need preparation by treatment with antibiotics, clarification of

debris, or disruption of mucus.

3. Appropriate cell lines for the virus(es) sought are chosen and inoculated, taking

care that the cells are metabolically healthy; that cells are being grown in an

appropriate cell culture medium and serum concentration, and the cultures are

94