ABSTRACT
Human papillomaviruses cannot be routinely grown in cell culture and serological assays, now being developed, are beset by poor sensitivity and cross-reactivity of antigens. Nucleic acid probes are not the initial method of choice for all these viruses, however, as antigen detection, for example for hepatitis B virus, is sufficiently sensitive at the clinically relevant time in most cases. With viruses expected to be present in low concentrations, nested PCR is often used and adds to specificity; the increased sensitivity also, however, makes the risk of false positives due to contamination greater. With specimens which may have a number of different viruses or even mixed infections, multiplex PCR methods have been developed. It is helpful to be cognizant of this variation for a number of reasons: to identify the spread of outbreaks; to understand the natural epidemiology of viruses including animal reservoirs; and to develop more effective vaccines.
