General Virology and DNA Viruses
Which specimen is best for detection of cytomegalovirus?
a. The diagnosis of a viral infection is made easier by the creation of a greater number of diagnostic virology laboratories during the past few decades. In order for viral diagnosis to be successful, the most appropriate specimen must be collected for the disease in question.
b. *Human papillomavirus (HPV) is often detected microscopically in cervical biopsies. Alternatively, there are methods to detect HPV DNA in such tissues as well as to serotype the virus. Evidence suggests that some HPV serotypes are more likely than others to cause cervical cancer. Add photograph from Jawely 24th ed. Extra edge Different layears of epidermis ur HPV .
c. Many viruses have a viremic phase, but only a few, such as CMV persist after the patient becomes symptomatic. CMV can be isolated from lymphocytes and polymorphonuclear leukocytes. This usually requires special separation procedures, particularly in those compromised patients who may be neutropenic.
d. Enteroviruses such as echoviruses and coxsackieviruses are the pre dominant cause of aseptic viral meningitis. While enterovirus infections are often diagnosed by specific antibody response, it is possible to isolate the virus from CSE Herpes simplex virus (HSV) can also be isolated from CSF in cases of herpes encephalitis or meningitis.
e. VZV and HSV are most often recovered from skin lesions, although varicella 1gM antibody detection may be the most rapid way to diagnose acute VZV infection. Detection and identification of these viruses is essential because of the availability of antiviral agents such as acyclovir. Other viruses, such as enteroviruses and paramyxoviruses, cause skin lesions.
f. Many viruses can be isolated from feces. Of the viral groups in these questions, adenovirus 40/41 is the most common stool isolate. Norwalk agent and other caliciviruses may also be isolated or detected from stools, but usually only in specialized laboratories.
Extra Edge: *
Schematic representation of a skin wart (papilloma). The papillomavirus life cycle is tied to epithelial cell differentiation. The terminal differentiation pathway of epidermal cells is shown on the left. Events in the virus life cycle are noted on the right. Late events in viral replication (capsid protein synthesis and virion morphogenesis) occur only in terminally differentiated cells. (Reproduced with permission from Butel JS: Papovaviruses. In: Medical Microbiology, 3rd ed. Baron S [editor]. Churchill Livingstone, 1991. )