EBV infection is not necessarily sexually transmitted. You can exchange saliva and virus in other ways. #MSBlog #MSResearch
In response to the comment: “…… I notice that your collaborator Prof Hawkes believes that MS is caused by child abuse…..”
“It may be worth reading the paper. Any theory about causation needs to be read in the context of causation theory. Unfortunately, Dr Hawkes did not do this when he framed his hypothesis; if he did he may have come to an alternative explanation regarding the cause of MS. You need to remember that there is a science behind causation. It started way back in the later 1800’s when Robert Koch formulated his postulates to persuade his contemporaries that the he had found the cause of tuberculosis.”
Koch’s postulates are:
1. The specific organism should be shown to be present in all cases of animals suffering from a specific disease but should not be found in healthy animals.
2. The specific microorganism should be isolated from the diseased animal and grown in pure culture on artificial laboratory media.
3. This freshly isolated microorganism, when inoculated into a healthy laboratory animal, should cause the same disease seen in the original animal.
4. The microorganism should be reisolated in pure culture from the experimental infection.
Kochs’s postulates served us well, but broke down when we tried to apply them to viruses that only have one host. It then fell to the British Statistician, Sir Austin Bradford-Hill, to formulate more general and appropriate criteria of causation; the following are the Bradford-Hill criteria:
1. CONSISTENCY AND UNBIASEDNESS OF FINDINGS
2. STRENGTH OF ASSOCIATION
3. TEMPORAL SEQUENCE
4. BIOLOGICAL GRADIENT (DOSE-RESPONSE RELATIONSHIP)
6. COHERENCE WITH BIOLOGICAL BACKGROUND AND PREVIOUS KNOWLEDGE
7. BIOLOGICAL PLAUSABILITY
8. REASONING BY ANALOGY
9. EXPERIMENTAL EVIDENCE
If you are interested in reading about these criteria I suggest the following references:
Bradford-Hill’s criteria have also been modified to apply them to the problem of MS:
“When you apply Bradford-Hill’s criteria to MS as being a caused by EBV several of the Bradford-Hill criteria can be ticked. When you apply these criteria to MS being a sexually transmitted disease, a few if any can be ticked and, finally, in relation to MS being caused by child abuse you can’t tick any of the boxes. So in summary, I don’t think MS is caused by child abuse; there is simply no evidence to support this hypothesis. However, the jury is still out on MS being possibly sexually transmitted. I am convinced that EBV is involved in the causal pathway of MS. EBV is transmitted by saliva. The process of exchanging saliva, particularity after childhood, usually requires intimate contact and hence the pattern of infection of EBV in relation to infectious mononucleosis looks similar to a sexually transmitted disease. In fact Dorothy Crawford, an EBV expert from Edinburgh, claims that EBV infection may be sexually transmitted in ~15% of cases. The following paper puts her claim into context.”
To determine the role of sexual contact in transmission of Epstein-Barr virus (EBV) and occurrence of infectious mononucleosis (IM), a cross-sectional study was undertaken of EBV serologic testing and histories of IM and sexual behavior among 1006 new students at Edinburgh University. Prevalence of EBV seropositivity was significantly greater among women (79.2%) than among men (67.4%; P <.001) and among those who had ever been sexually active (82.7%) than among those who had not (63.7%; P <.OOl). Having a greater number of sex partners was a highly significant risk factor for EBV seropositivity. Two thirds of IM cases, but only a tenth of asymptomatic primary EBV infections, were statistically attributable to sexual intercourse. The findings suggest that EBV transmission occurs during sexual intercourse or closely associated behaviors. Transmission in this way appears to account for most cases of IM but for only a minority of cases of asymptomatic EBV infection, which mainly occur at younger ages.