It is a myth that dust mites bite humans. Google "dust mite bites" and you will find:
"Have red, itching bumps on the skin? Are you scared of dust mite bites? Don’t worry, they DON’T bite people. Surprised?"
"Dust mites DON'T bite! Shocking surprise, right? Dust mite bites are merely a myth."
"Unlike other common household bugs (fleas, for example), dust mites don't bite."
The various sites all have the same info. And one site has a warning:
"Warning Dust mites love rugs and carpeting. So, vacuum the carpets weekly. To really ditch possible dust-mite allergies leave the floors bare."
I cannot remember the last time I was in a carpeted Jamaican home or establishment - all had bare floors so dust mites bites are a non-issue.
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As for sand fleas, by definition they are "sand" creatures. According to the "Orkin Man":
"Although the real sand fleas can prove deadly to their small marine prey, they do not live within human homes and will not infest pets."
http://www.orkin.com/other/fleas/sand-fleas/