Efficacy of antimalarial chemoprophylaxis among French residents travelling to Africa

Compliance with Primary Malaria Chemoprophylaxis: Is Weekly Prophylaxis Better Than Daily Prophylaxis?

BACKGROUND

Chemoprophylaxis is an effective tool for individuals to minimize their risk of contracting malaria and serves an important public health role in preventing imported malaria. Yet, it is only effective if the traveller is fully compliant with the prescribed regimen. For many destinations, a choice of prophylactic agents is available, so historical compliance data can be helpful for both physicians and travellers to make an informed decision.

METHODS

We analyzed the historical self-reported compliance data for six chemoprophylactic agents currently recommended by CDC for primary malaria chemoprophylaxis by searching PubMed, Embase, CINAHL, Web of Science, and Scopus for observational studies reporting on travelers within the last 25 years. The quality of data was graded as "good" or "poor" using the NIH quality assessment tool for cohort and cross-sectional studies. Cumulative compliance data were compiled for all studies (gross compliance) and the subgroup of studies with "good" quality evidence (refined compliance). Subgroup analyses were performed for weekly vs daily administered regimens, between military and civilian travelers, and across each prophylactic agent.

RESULTS

Twenty-four eligible studies assessed compliance for mefloquine (n=20), atovaquone-proguanil (n=11), doxycycline (n=13), and chloroquine (n=3). No studies were found for primaquine or tafenoquine. Both gross and refined compliance were significantly better for weekly regimens than daily regimens (P<0.0001). Stopping chemoprophylaxis due to adverse events was significantly more for doxycycline (P<0.0001) compared to other drugs. Compliance was significantly worse in military travelers, but they were also more likely to be prescribed doxycycline.

CONCLUSION

Malaria chemoprophylaxis for a traveler should depend on prevailing resistance patterns at destination, current national guidelines, and patient preferences. However, when there is a choice, historical compliance data are useful to select a regimen that the traveler is more likely to comply with.

Malaria in tunisian military personnel after returning from external operation

Introduction. Malaria had been eliminated in Tunisia since 1979, but there are currently 40 to 50 imported cases annually. Soldiers are no exception as the incidence of imported malaria is increasing in Tunisian military personnel after returning from malaria-endemic area, often in Sub-Saharan Africa. Methods. We retrospectively analyzed the clinical and biological presentations, treatment, and outcomes of 37 Tunisian military personnel hospitalized at the Department of Internal Medicine, the Military Hospital of Tunis, between January 1993 and January 2011, for imported malaria. The clinical and laboratory features were obtained from the medical records and a questionnaire was filled by the patients about the compliance of malaria prophylaxis. Results. Thirty-seven male patients, with a mean age of 41 years, were treated for malaria infection. Twenty-two were due to Plasmodium falciparum. The outcome was favourable for all patients, despite two severe access. The long-term use of chemoprophylaxis has been adopted by only 21 (51%) of expatriate military for daily stresses. Moreover, poor adherence was found in 32 patients. Conclusion. The risk of acquiring malaria infection in Tunisian military personnel can largely be prevented by the regular use of chemoprophylactic drugs combined with protective measures against mosquito bites.

Chemoprophylaxis compliance in a French battalion after returning from malaria-endemic area

Incidence of malaria is increasing in travelers and soldiers. In 2006, a survey was performed in a French battalion returning from a malaria-endemic area. According to the chemoprophylaxis plasma concentration and the individuals' reports, the noncompliance rates were high, respectively, 63.4 and 54.7%.

Remote sensing and malaria risk for military personnel in Africa

BACKGROUND

Nonimmune travelers in malaria-endemic areas are exposed to transmission and may experience clinical malaria attacks during or after their travel despite using antivectorial devices or chemoprophylaxis. Environment plays an essential role in the epidemiology of this disease. Remote-sensed environmental information had not yet been tested as an indicator of malaria risk among nonimmune travelers.

METHODS

A total of 1,189 personnel from 10 French military companies traveling for a short-duration mission (about 4 mo) in sub-Saharan Africa from February 2004 to February 2006 were enrolled in a prospective longitudinal cohort study. Incidence rate of clinical malaria attacks occurring during or after the mission was analyzed according to individual characteristics, compliance with antimalaria prophylactic measures, and environmental information obtained from earth observation satellites for all the locations visited during the missions.

RESULTS

Age, the lack of compliance with the chemoprophylaxis, and staying in areas with an average Normalized Difference Vegetation Index higher than 0.35 were risk factors for clinical malaria.

CONCLUSIONS

Remotely sensed environmental data can provide important planning information on the likely level of malaria risk among nonimmune travelers who could be briefly exposed to malaria transmission and could be used to standardize for the risk of malaria transmission when evaluating the efficacy of antimalaria prophylactic measures.

Risk factors for imported fatal Plasmodium falciparum malaria, France, 1996-2003

Plasmodium falciparum malaria is a serious health hazard for travelers to malaria-endemic areas and is often diagnosed on return to the country of residence. We conducted a retrospective study of imported falciparum malaria among travelers returning to France from malaria-endemic areas from 1996 through 2003. Epidemiologic, clinical, and parasitologic data were collected by a network of 120 laboratories. Factors associated with fatal malaria were identified by logistic regression analysis. During the study period, 21,888 falciparum malaria cases were reported. There were 96 deaths, for a case-fatality rate of 4.4 per 1,000 cases of falciparum malaria. In multivariate analysis, risk factors independently associated with death from imported malaria were older age, European origin, travel to East Africa, and absence of chemoprophylaxis. Fatal imported malaria remains rare and preventable. Pretravel advice and malaria management should take into account these risk factors, particularly for senior travelers.

Special infectious disease risks of expatriates and long-term travelers in tropical countries. Part I: malaria

Malaria risk is dependent upon the entomological inoculation rate actually faced by the long-term traveler. Risk is cumulative, increases with duration of exposure, is greatest in rural and periurban areas, and least in urban centers. Risk may be zero in some urban centers, especially during dry seasons. Chemoprophylaxis compliance is hindered by the high adverse event rate often reported by users, is often suboptimal in expatriates, and decreases with duration of stay. Compliance with personal protection measures may also be suboptimal, and use of insecticide-treated nets and effective repellents should be encouraged. Alternative strategies to mitigate risk include seasonal chemoprophylaxis, nonuse of chemoprophylaxis with rapid treatment, self-testing, self-treatment where competent care and quality drugs are unavailable, and vector control. Choice of strategies will depend upon assessment of actual risk and likely compliance, with a combination of measures usually appropriate.

Knowledge, attitudes and practices of expatriates towards malaria chemoprophylaxis and personal protection measures on a mine in Mali

A questionnaire survey of malaria chemoprophylaxis knowledge, attitudes, and practices of 90 expatriates on a Mali mine yielded 68 (75.5%) responses. A total of 49 (72%) subjects took perennial chemoprophylaxis, 6 (9%) were children <5 years. Out of 68, 13 (19%) took chemoprophylaxis during the high transmission season only and 10 (15%) never took chemoprophylaxis. Reasons advanced for not taking chemoprophylaxis were concern over adverse effects, presumed immunity from long term residence in Africa, and on site access to quality medical care. Chemoprophylactics used were: atovaquone-proguanil 1 (2%); chloroquine and proguanil 15 (30%); doxycycline 16 (33%); mefloquine 17 (35%). Thirteen out of 49 (27%) subjects admitted to missing chemoprophylaxis doses and 15/68 (22%) had suffered malaria while on chemoprophylaxis. Fifteen out of 49 (31%) low season chemoprophylaxis users and 4/19 (21%) non-users contracted low season malaria (chi(2), p=0.63). A total of 46 (68%) used insect repellants, 50 (74%) used insecticide sprays or coils in rooms, 9 (13%) slept under insecticide treated nets. Malaria control in expatriates requires improvement; additional strategies for consideration that require reduced compliance requirements by expatriates are suggested, including residual spraying, seasonal chemoprophylaxis use, and emergency stand by medication.

Efficacy of chloroquine–proguanil malaria prophylaxis in a non-immune population in Bangui, Central African Republic: a case–control study

A case-control study was conducted to evaluate the efficacy of the combination of chloroquine plus proguanil as malaria prophylaxis in a non-immune population living in the Central African Republic. Cases were patients presenting with a malaria attack confirmed by a positive blood film and/or an HRP2 positive antigen test at the Pasteur Institute of Bangui. Two control subjects were included per case: one was a relative or close friend and the other was matched to the patient with respect to the length of stay. A questionnaire assessing malaria prophylaxis habits and malarial risk factors over the 2-month period prior to inclusion in the study was given to 48 cases and 96 controls. A conditional logistic regression was used to identify risk factors. The efficacy of the chloroquine plus proguanil regimen was found to be high (95.5%, 95% CI 74.0-99.2%) in this country known for high chloroquine resistance. Our data lend some support to the use of chloroquine plus proguanil in Bangui, and the protective efficacy of chloroquine plus proguanil should now be studied prospectively as part of a randomised controlled trial of various prophylactic drugs.

Travelling to Africa: health risks reviewed

Africa's varied ecology presents a wide range of travel health threats: infections; accidents; envenomations; an uncertain drug supply; problematic access to competent medical care outside South Africa. Important vaccine preventable diseases include yellow fever, meningococcal disease, typhoid, polio, rabies, and hepatitis A and B; routine vaccinations should be up to date. Much, but not all, of sub-Saharan Africa is malarious with chloroquine resistant falciparum dominating; chemoprophylaxis and personal protection measures will often be indicated. Other threats are less obvious, e.g. helminth and protozoal infections. The immunocompromised and other high-risk groups may require special attention. Risk mitigation strategies may include education, vaccination, chemoprophylaxis, personal protection measures, provision of treatment and equipment packs, behaviour modification, and evacuation insurance.