The nonspecific symptoms of malaria make it difficult for patients to self-diagnose the disease, Dr. Schlagenhauf-Lawlor said. In a study of 1,187 Swiss travelers who carried medication for SBET, about 10% became ill with fever while traveling. Even though only nine of the travelers were out of the reach of medical attention, most of those who were ill reacted to their illness contrary to SBET instructions and delayed in seeking medical attention (Bull. World Health Organ. 1995;73:215–21).
A combination of SBET and rapid malaria tests “could be useful for certain selected long-term travelers,” she said. Studies have reported that 68%–91% of travelers were able to use the tests successfully. But the tests can generate false-positive results and have been difficult for travelers to read at low levels of parasitemia.
Seasonal Prophylaxis
In all but a few countries “it's almost impossible for an adviser to say in advance how the season will be at the destination,” Dr. Schlagenhauf-Lawlor said.
In the sub-Saharan countries of South Africa, Namibia, and Botswana, the transmission seasons are fairly stable, but can shift. In South Africa, travelers may want to use continuous prophylaxis during the high-risk season of October through May and revert to SBET during the low-risk season of June through September. But travelers should always use personal protective measures.
The high-risk season of November through June in Namibia and Botswana warrants continuous prophylaxis, while SBET and personal protective measures could be used at other times. In cases where seasonal prophylaxis may be possible, she advised that it may be best for travelers to take continuous prophylaxis for at least 6 months and then seek local advice afterward regarding the seasonal threat of malaria.
Blood-feeding Anopheles gambiae mosquitos are a leading malaria vector.