I guess if a drugstore or grocery store is near while your visiting Roatan you could check for it. I read a forum post made by a man that grew up in Jamaica and he said he used Zanzarin so if you can get it in Jamaica maybe its available in other Carib countries as well. Cant hurt to check. :) Here is some additional info on Zanzarin:
Basically...Tungiasis is a skin disease you can get when bitten by a female Sand Flea.
Public Health and Prevention Studies
Due to the high number of hosts, eradication of tungiasis is not feasible, at least not easily so. Public health and prevention strategies should then be done with elimination as the target. Better household hygiene, including having a cemented rather than a sand floor, and washing it often, would lower the rates of tungiasis significantly.
Though vaccines would be useful, due to the ectoparasitic nature of chigoe flea, they are neither a feasible nor an effective tool against tungiasis. Nevertheless, due to the high incidence of secondary infection, those at risk of tungiasis should get vaccinated against tetanus. A better approach is to use repellents that specifically target the chigoe flea.
One very successful repellent is called Zanzarin, a derivative of coconut oil, jojoba oil, and aloe vera. In a recent study involving two cohorts, the infestation rates dropped 92% on average for the first one and 90% for the other. Likewise, the intensity of the cohorts dropped by 86% and 87% respectively. The non-toxic nature of Zanzarin, combined with its “remarkable regression of the clinical pathology” make this a tenable public health tool against tungiasis.
Edited: 20 January 2011, 22:39