Mexico: Rural areas, including resorts in the rural areas, of the following states: Campeche, Chiapas, Guerrero, Michoacan, Nayarit, Oaxaca, Quintana Roo, Sinaloa, and Tabasco. Antimalarial drugs are not recommended for travel to the major resort areas on the Pacific and Gulf coasts, although travelers should use anti- mosquito measures.

Cancun is located in Quintana Roo but, of course, would not be considered a rural area. So, according to the CDC, anti-malarial drugs are not recommended but anti-mosquito measures are.

The problem with this ambiguous warning is that for many travelers a visit to Cancun might include a day trip to more rural areas (such as a site of Mayan ruins, the remotely located cenotes, or a more distant beach adjacent to a lagoon). If these trips are taken within a short time after a significant rainfall the anopheles mosquito will have started its lifecycle and could very well be exposing unwary travelers to malaria (likewise for the mosquitos that carry dengue).

As you mentioned, your friend, Bob, was a frequent visitor to the area. Undoubtedly, he did some extensive exploration of the area (I know I have, and will continue to do so). His explorations probably took him outside of the mosquito-spraying areas i.e., Cancun and other more populous settlements, thus exposing him to the disease.

I have visited all of the states listed in the CDC warnings and, over the last few years have escorted groups to the coasts of Michoacan and Oaxaca, with another group headed to the Yucatan this fall. I have always directed my fellow travelers to consult with a travel clinic before accompanying me on my trips. I make sure they are aware of the CDC's suggested methods of avoiding insect bites plus I urge them to take one of the prophylactic medications.

Are these precautions necessary if the traveller is just going to Acapulco, Puerto Vallarta, or even Cancun? Probably not. But if they intend to do some more wide-ranging sight-seeing then, I would say, absolutely.

Unfortunately, many travel clinics only consider that the Mexico-bound traveler is headed to one of these major resorts. So they don't inform their patients of the possible risks outside these areas. In fact, I have found myself educating my own attending physician at my travel clinic about a recent outbreak of malaria and dengue fever along the coast of Oaxaca just prior to my visit there two years ago. This was after she had informed me that malarial medication would be unnecessary.

Personally, I use the CDC's website to monitor what areas are malarial. If the surrounding area of a town I'm visiting is malarial then I take the propylactic medication and use anti-mosquito measures. The risk not to is to high as far as I'm concerned.

Sorry about the length, but as others on this group can attest I get pretty fired up when it comes to Mexico.

John Rule San Diego, CA