Detection of persistent measles virus infection in Crohn's disease: current status of experimental work

Epidemiological studies may generate a hypothesis regarding the aetiology of chronic diseases that may be tested directly. In the case of persistent infections, demonstration of a putative organism by a sensitive and specific test provides essential evidence in favour of such a hypothesis. The measles virus hypothesis had generated considerable excitement, attracted resources, and spurred Crohn's disease researchers to perform corroborative tests. It also however had undesirable effects on uptake of immunisation, a potential public health hazard. As a number of well conducted studies to demonstrate measles virus genome in Crohn's disease tissues using state of the art RT-PCR based assays have proved to be negative, it must be concluded that the persistent measles virus infection hypothesis in the aetiology of Crohn's disease lacks confirmatory evidence. There is now enough experimental evidence to conclude that failure to detect measles virus genome in IBD tissues is not due to the inefficiencies of the PCR based detection systems but to the absence of measles virus particles. The challenge facing the medical profession is to convince the public that there is no evidence of measles virus persistence in the intestine of Crohn's disease patients.