I do not think that autism is a disease. Autistic people are just a small group of people who live in a different world. They have their own way to communicate, the way that may be weird to normal people. Their behaviors are always considered to be unreasonable, however, I think there must be some reason which we do not know.
People have wasted to much time on finding the factors that cause autism. They attributed it to mothers, foods, vaccine, or gene, and tried everything to fix their "sick" children. Since autism is a lifelong disorder, I think people should accept that, which means that autistic people are not sick, they are just different. They may be have barriers to our "normal" world, the best thing we can do is to build a bridge between their world and ours. It just like two people talk to each other with two different languages, the key point is try to understand. One of my friends has been work with autistic children for nearly 10 years, she told me that when these children hurt you, they would not apologize for their behavior, but they would do something you like, that is their way to say "sorry".
If we treated them as sick people and try to fix them, we would never understand their behavior s and help them live a better life. Some of them have high IQ or special skills, these ones will be very successful in appropriate positions. The best way to help them is to find their position and let them enjoy their lives.