Standby Emergency Treatment of Malaria in Travelers

Experience to Date and New Developments

Patricia Schlagenhauf; Eskild Petersen

Disclosures

Expert Rev Anti Infect Ther. 2012;10(5):537-546. 

In This Article

Policy of Using SBET as a Stand Alone Strategy

For travelers visiting low malaria risk areas (Figure 1), the German-speaking countries recommend no chemoprophylaxis but advise travelers to use anti-mosquito bite measures and to carry a quality malaria treatment for emergency use under medical supervision. This approach is based on a risk–benefit analysis. The goal of chemoprophylaxis is to prevent symptomatic malarial infection, although the practice carries a risk of adverse events. Depending on study design and definitions, up to 75% of users of any chemoprophylaxis will report perceived adverse events if all mild adverse reactions are included, and 5.8–12.4% will report a 'severe adverse event,' that is, a perceived drug reaction that limits their activity.[15] Serious adverse events (e.g., events that require hospitalization) are rare (approximately one per 10,000 users of chemoprophylaxis) but have been reported with all chemoprophylactic regimens.[16] These figures show that a risk–benefit analysis (adverse events vs avoided infections) is necessary for travelers minimally exposed to malaria infection. Most of sub-Saharan Africa, Papua New Guinea and some parts of Indonesia such as Lombok are documented high-risk areas for travelers. There is a markedly lower incidence in South and central America (0.05 and 0.01%, respectively).[17] A more recent analysis shows that 302 per 100,000 visitors to west Africa will acquire malaria compared with 7.2 per 100,000 visitors to South America and two per 100,000 visitors to Thailand.[17] These numbers include travelers who take chemoprophylaxis medication as well as those not taking prophylactic medication. The gradient of malaria risk in travelers is shown in Table 1.

Figure 1.

Map showing the use of prophylaxis and standby emergency treatment according to the malaria guidelines of the German-speaking countries.
Adapted with permission from [106].

For the low-risk, malaria-endemic areas of Asia and South America, the risk of adverse events from chemoprophylaxis can actually outweigh the benefit of avoided infection. Furthermore, it is recognized that no antimalarial prophylactic regimen gives complete protection, and this is especially true in areas of high transmission of resistant P. falciparum.[103] Additional protection against breakthrough malaria can be afforded by the availability of a 'standby' emergency therapy.

A recent study on the risk of malaria in travelers to India showed a marked decline in the numbers of malaria cases imported from India and a very low proportion of P. falciparum malaria.[18] This has prompted the central European countries – Germany, Switzerland and Austria – to recommend SBET rather than continuous chemoprophylaxis for the entire Indian subcontinent. Constant surveillance of malaria is necessary and can lead to changes and flexibility in recommendations and the use of chemoprophylaxis for at-risk travelers, particularly in full travelers visiting certain regions in India may be justified. The risk of travelers acquiring malaria in southeast Asia is considered minimal, and the risk at most destinations does not warrant chemoprophylaxis.[19] However, notified imported malaria from Asia (87% Plasmodium vivax) to the USA has increased from 142 cases in 2009 to 285 cases in 2010.[7] These cases were imported to the USA mainly from India and Afghanistan.[7]

Clearly, malaria risk varies markedly according to the geographic area visited. The malaria prevention guidelines for Switzerland, Germany and Austria sanction the carriage of SBET and personal protection against mosquito bites as the preferred strategy for most of South America and Asia including India,[19–21] and the policy has recently been extended to include the island of Zanzibar due to the documented declining risk of malaria.[22] Thus, the German-speaking countries have a malaria risk and strategy map that is updated frequently depending on risk assessment at frequent traveler destinations (Figure 1).

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