Since autism generally is a mutation in the SHANK3 gene (or in the case of Asperger's multiple copies of a normal SHANK3 gene) , it seems strange that any fever would cause this one specific genetic change. Schizophrenia is also linked to the SHANK3 gene, and both autism and schizophrenia are more prevalent with older fathers. Maybe the fever could have something developmentally with unlocking it at clinical levels-but I doubt the cause. I say it is a condition that is unlocked because men are 3 times more likely to have it than women, and women tend to be more social. Also with Older fathers, it is less likely that the father will be in the same social circles as his kids peers' parents as would be the case of younger parents-likewise there would be a difference in interest between the generational or even half generational gap.
For people in my generation, it is likely brought on by being constantly bullied from others-often in the form of latent antisemitism. There are those who advance, myself included, that so far as asperger's is concerned, it more closely followed social rejection theory than autism. Mine is definitely an adolescent onset. Autism's increased prevalence over recent years I suspect is probably due to more kids becoming fixated on video games than in past generations which contributes to further social isolation, and unlocking the condition to clinically identifiable levels. And with kids becoming fixed on iphones, etc, at the further detriment of their social skills, it will probably continue to rise. Perhaps it may even spread to those who don't have either multiple copies of SHANK3 or the mutation of the SHANK3.
Stop letting the iphone or playstation babysit your kids. Get them out to play games, study, etc, with other kids their age.