Warning : I am writing this on 13 March 2020 and the graphic on the left is from 12 March 2020 and comes from the Department of Disease Control Thailand. This graphic is not meant as information about the corona virus. And I am not a medical specialist, so what I am going to write now is based on my own interpretation of the news and medical information that is currently available.
For more information about the corona virus in Thailand you might better have a look at Wikipedia about the 2020 coronavirus outbreak in Thailand or Department of Disease Control Thailand : Viral Pneumonia.
The corona virus is now a worldwide pandemic according to the WHO. And the Thai government is taking all kind of strict measurements to prevent further escalation in Thailand. So if you are planning to go traveling to Thailand please check the situation in regards if you can fly to Thailand and if you are welcome. For Questions & Answers about this see DDC Q&A. Another good information website is IATA - International Travel Documents News.
Just as all over the world major events are cancelled in Thailand, like many parts of Songkran are cancelled and the GP of Thailand. Also be aware that some airlines are canceling domestic flights. Although the TAT still tries to sell the sunny beaches of Thailand they also have Thailand Tourisme Updates.
Disclaimer : All information is created in good faith and is an expression of fair comment.