Be prepared as well to explain how you would deal with close contact with scabies, lice and tapeworm.
The question may be more relevant than it seems. If you are caring / supporting them, it may part of your duties to ensure they are reasonably educated in maintaining basic hygienic standards.
After all, if a disabled child has low immunity and is crawling around in dog mess, for example, it has to be dealt with.
Make sure you fully understand the role and responsibilities of the job before the interview - then you will be well prepared.