Environmental determinant of malaria cases among travellers.

BACKGROUND: Approximately 125 million travellers visit malaria-endemic countries annually and about 10,000 cases of malaria are reported after returning home. Due to the fact that malaria is insect vector transmitted, the environment is a key determinant of the spread of infection. Geo-climatic factors (such as temperature, moisture, water quality) determine the presence of Anopheles breeding sites, vector densities, adult mosquito survival rate, longevity and vector capacity. Several studies have shown the association between environmental factors and malaria incidence in autochthonous population. The association between the incidence of clinical malaria cases among non-immune travellers and environmental factors is yet to be evaluated. The objective of the present study was to identify, at a country scale (Ivory Coast), the environmental factors that are associated with clinical malaria among non-immune travellers, opening the way for a remote sensing-based counselling for malaria risk prevention among travellers. METHODS: The study sample consisted in 87 cohorts, including 4,531 French soldiers who travelled to Ivory Coast, during approximately four months, between September 2002 and December 2006. Their daily locations were recorded during the entire trip. The association between the incidence of clinical malaria and other factors (including individual, collective and environmental factors evaluated by remote sensing methods) was analysed in a random effect mixed Poisson regression model to take into account the sampling design. RESULTS: One hundred and forty clinical malaria cases were recorded during 572,363 person-days of survey, corresponding to an incidence density of 7.4 clinical malaria episodes per 1,000 person-months under survey. The risk of clinical malaria was significantly associated with the cumulative time spent in areas with NDVI > 0.35 (RR = 2,42), a mean temperature higher than 27°C (RR = 2,4), a longer period of dryness during the preceding month (RR = 0,275) and the cumulative time spent in urban areas (RR = 0,52). CONCLUSIONS: The present results suggest that remotely-sensed environmental data could be used as good predictors of the risk of clinical malaria among vulnerable individuals travelling through African endemic areas.

The accuracy of self-reported data concerning recent cannabis use in the French armed forces.

BACKGROUND: The aims were to evaluate the accuracy of self-report of past-month cannabis use in a representative sample of French military staff members and to evaluate the scale of the prevarication bias. METHOD: Data from three cross-sectional surveys conducted between 2005 and 2008 (n = 3493) were used. The characteristics of self-report (sensitivity, specificity, positive predictive value and negative predictive value) were computed using tetrahydrocannabinol detection in urine as the reference. RESULTS: The prevalence for past-month cannabis use was 16.1% and for positive testing was 13.4%. The discriminant power of self-report was good, with an area under the receiver operating characteristics curve 0.90. Specificity (94.5%) and negative predictive values (97.8%) were good, but sensitivity (85.7%) and positive predictive values (70.4%) were lower. The lowest sensitivity values were observed in the higher categories of personnel and in the Navy, which could reflect some prevarication in these sub-populations who might believe they were more exposed to sanctions if detected. CONCLUSIONS: Despite certain limitations of urine analysis as a reference, because of its poor detection of occasional users, our study is in favour of good accuracy of self-reported data on cannabis use, even among the military. However, our results, derived from a population study, do not enable any assumptions on the validity of self-reported data collected during individual testing procedures for the purpose of improving occupational safety.

[Laveran and the Nobel Prize in Physiology or Medicine]. / Laveran et le Prix Nobel de physiologie ou de médecine.

This article recalls the conditions under which the first Nobel Prizes were awarded. The scientific personalities who nominated Alphonse Laveran for the prize from 1901 to 1907 are recalled, among them Ronald Ross, winner in 1902. In 1907, Karl Axel Hampus Mörner submitted Alphonse Laveran for the prize. He was then the rector of the Karolinska Institutet, as well as the chairman of the Nobel Committee and the Nobel Assembly, and had never before expressed an interest in one scientist more than another. The previous year, the Nobel Assembly had for the first time awarded the prize for physiology or medicine to two laureates, Camillo Golgi and Santiago Ramón y Cajal "in recognition of their work on the structure of the nervous system". In 1907, the numerous, repeated and simultaneous nominations of Élie Metchnikoff and Paul Ehrlich were probably the subject of an important debate, which finally turned out in favour of Alphonse Laveran. We explain why we think the choice of the president prevailed. In 1908, when Laveran became one of the nominators of the prize, his main competitors of 1907 were finally crowned simultaneously "in recognition of their work on immunity".The long delay between the discovery of the malarial parasite (1880) and the award of the prize "in recognition of his work on the role played by protozoa in the appearance of diseases" is put into perspective and illustrates what will almost always be the practice, contrary to Alfred Nobel's rule of awarding the prize within a year after the discovery. The particular circumstances of the award of the prize in 1907 are described.The donation that Alphonse Laveran made on December 22nd 1907 to the Pasteur Institute out of the amount of his prize was 100,000 francs, i.e. a little more than half of the 190,000 francs grant received from the Nobel Committee. Its value, in terms of purchasing power in euros 2021, is estimated at over 400,000 euros. The use made of it by the Pasteur Institute is clearly shown in the minutes of its Board of Directors in 1908, as having been mainly devoted to the fitting out and equipment of the Laboratory of Tropical Diseases that Laveran was calling for in the buildings recently purchased on Rue Falguière (Paris); the donation was not used for the construction of new buildings.

[Médecine Tropicale et Santé Internationale takes a stand against editorial predation]. / Médecine Tropicale et Santé Internationale s'engage contre la prédation éditoriale.

Warnings against predatory journals get stronger. Designed to capture manuscripts with the promise of rapid publication, the main aim of these journals is to charge abusive publication fees. Sometimes boasting imaginary impact factors, they are not indexed and offer no guarantee of visibility, accessibility or durability of the published article. Above all, they have no concern for the rigor and scientific integrity of the work they publish.

Plasmodium vivax Malaria among military personnel, French Guiana, 1998-2008.

We obtained health surveillance epidemiologic data on malaria among French military personnel deployed to French Guiana during 1998-2008. Incidence of Plasmodium vivax malaria increased and that of P. falciparum remained stable. This new epidemiologic situation has led to modification of malaria treatment for deployed military personnel.

Use of short message service (SMS) to improve malaria chemoprophylaxis compliance after returning from a malaria endemic area.

BACKGROUND: Malaria chemoprophylaxis compliance is suboptimal among French soldiers despite the availability of free malaria chemoprophylaxis and repeated health education before, during and after deployment to malaria endemic areas. METHODS: In 2007, a randomized controlled study was performed among a cohort of French soldiers returning from Côte d'Ivoire to assess the feasibility and acceptability of sending a daily short message service (SMS) reminder message via mobile device to remind soldiers to take their malaria chemoprophylaxis, and to assess the impact of the daily reminder SMS on chemoprophylaxis compliance. Malaria chemoprophylaxis consisted of a daily dose of 100 mg doxycycline monohydrate, which began upon arrival in Côte d'Ivoire and was to be continued for 28 days following return to France. Feasibility and acceptability were assessed by questionnaire. Cohort members were followed for a 28 day period, with compliance assessed by use of an electronic medication monitoring device, from which several indicators were developed: daily proportion of compliant individuals, average number of pills taken, and early discontinuation. RESULTS: Among 424 volunteers randomized to the study, 47.6% were assigned to the SMS group and 52.3% to the control group. Approximately 90% of subjects assigned to the SMS group received a daily SMS at midday during the study. Persons of the SMS group agreed more frequently that SMS reminders were very useful and that the device was not annoying. Compliance did not vary significantly between groups across the compliance indicators. CONCLUSION: SMS did not increase malaria chemoprophylaxis compliance above baseline, likely because the persons did not benefit from holidays after the return and stayed together. So the reminder by SMS was noted by all subjects of the study. Another study should be done to confirm these results on soldiers going on holidays from employment after return or with individual travellers.

Major variations in malaria exposure of travellers in rural areas: an entomological cohort study in western Côte d'Ivoire.

BACKGROUND: Malaria remains a major threat, to both travellers and military personnel deployed to endemic areas. The recommendations for travellers given by the World Health Organization is based on the incidence of malaria in an area and do not take the degree of exposure into account. The aim of this article is to evaluate the exposure of travellers by entomologic methods, which are the commonly used measures of the intensity of malaria transmission. METHODS: From February 2004 to June 2004, five groups of 30 military personnel were stationed in up to 10 sites in western Côte d'Ivoire, from one week to several months. Adult mosquitoes were collected by human landing catches at each site during the five months and the level of exposure to malaria transmission of each group was estimated. RESULTS: The level of transmission varied from one site to another one from less than one to approximately more than 100 infective bites per month. In the majority of sites, at least two anopheline species were involved in transmission. The cumulative EIR over the study period varied according to the groups from 29 infected bites per person/per mission to 324. CONCLUSION: The level of malaria transmission and malaria risk varies widely (varying by a factor of eleven) between groups of travellers travelling in the same region and at the same time. Physicians involved in travel medicine or supporting expatriated populations or refugees should consider this heterogeneity and emphasize the importance of combining appropriate measures, such as chemoprophylaxis and protective measures against mosquitoes.

Advantages and limits of real-time epidemiological surveillance during military deployments: the experience of the French Armed Forces.

To perform epidemiological surveillance during deployments, the French military health service has developed a real-time surveillance approach. The objective was to identify the benefits and problems of this approach. A prototype of real-time surveillance has been set up in French Guiana since 2004. Its permanent evaluation has allowed identifying strengths and weaknesses. The experience has permitted expansion of the concept to French forces in Djibouti and also development of a global approach for the whole French armed forces. Real-time surveillance has shown its usefulness for early warning during different real and simulated situations. Functional and architectural choices have permitted interoperability with allied nations. However, the information produced was only the first step of the diagnostic epidemiological situation followed by other investigations. This first step of development has highlighted the required complementarity with traditional epidemiological surveillance.

Characteristics of human intestinal Escherichia coli with changing environments.

To investigate if the characteristics of human intestinal Escherichia coli are changing with the environment of the host, we studied intestinal E. coli from subjects having recently migrated from a temperate to a tropical area. We determined the phylogenetic group, the prevalence of the antibiotic resistance, the presence of integrons and the strain diversity in faecal isolates from 25 subjects originally from metropolitan France and expatriated to French Guyana. These characteristics were compared with those of 25 previously studied Wayampi Amerindian natives of French Guyana and from 25 metropolitan French residents. The three groups of subjects were matched for age and sex, had not taken antibiotics for at least 1 month, nor had been hospitalized within the past year. In all, the characteristics of intestinal E. coli from Expatriates were intermediate between those found in residents from metropolitan France and those found in natives of French Guyana. Prevalence of carriage of resistant Gram-negative bacteria in Expatriates was intermediate between French residents and Wayampi as were the prevalence of integrons in E. coli (12.3% versus 16.3% and 7.8% respectively), and the intra-host diversity of E. coli (2.3 strains/subject versus 1.9 and 3.1, respectively); lastly, in Expatriates, the prevalence of carriage of phylogenetic group B2 strains was lower than in French residents (16% versus 56%, P = 0.005), while carriage of phylogenetic group A strains was lower than in Wayampi (56% versus 88%, P = 0.03). Our results suggest that the composition of the commensal intestinal flora of humans is not static but changes dynamically in response to new environmental conditions.

Evaluation of a syndromic surveillance for the early detection of outbreaks among military personnel in a tropical country.

BACKGROUND: To evaluate a new military syndromic surveillance system (2SE FAG) set up in French Guiana. METHODS: The evaluation was made using the current framework published by the Centers for Disease Control and Prevention, Atlanta, USA. Two groups of system stakeholders, for data input and data analysis, were interviewed using semi-structured questionnaires to assess timeliness, data quality, acceptability, usefulness, stability, portability and flexibility of the system. Validity was assessed by comparing the syndromic system with the routine traditional weekly surveillance system. RESULTS: Qualitative data showed a degree of poor acceptability among people who have to enter data. Timeliness analysis showed excellent case processing time, hindered by delays in case reporting. Analysis of stability indicated a high level of technical problems. System flexibility was found to be high. Quantitative data analysis of validity indicated better agreement between syndromic and traditional surveillance when reporting on dengue fever cases as opposed to other diseases. CONCLUSIONS: The sophisticated technical design of 2SE FAG has resulted in a system which is able to carry out its role as an early warning system. Efforts must be concentrated on increasing its acceptance and use by people who have to enter data and decreasing the occurrence of the frequency of technical problems.

Proposal of a framework for evaluating military surveillance systems for early detection of outbreaks on duty areas.

BACKGROUND: In recent years a wide variety of epidemiological surveillance systems have been developed to provide early identification of outbreaks of infectious disease. Each system has had its own strengths and weaknesses. In 2002 a Working Group of the Centers for Disease Control and Prevention (CDC) produced a framework for evaluation, which proved suitable for many public health surveillance systems. However this did not easily adapt to the military setting, where by necessity a variety of different parameters are assessed, different constraints placed on the systems, and different objectives required. This paper describes a proposed framework for evaluation of military syndromic surveillance systems designed to detect outbreaks of disease on operational deployments. METHODS: The new framework described in this paper was developed from the cumulative experience of British and French military syndromic surveillance systems. The methods included a general assessment framework (CDC), followed by more specific methods of conducting evaluation. These included Knowledge/Attitude/Practice surveys (KAP surveys), technical audits, ergonomic studies, simulations and multi-national exercises. A variety of military constraints required integration into the evaluation. Examples of these include the variability of geographical conditions in the field, deployment to areas without prior knowledge of naturally-occurring disease patterns, the differences in field sanitation between locations and over the length of deployment, the mobility of military forces, turnover of personnel, continuity of surveillance across different locations, integration with surveillance systems from other nations working alongside each other, compatibility with non-medical information systems, and security. RESULTS: A framework for evaluation has been developed that can be used for military surveillance systems in a staged manner consisting of initial, intermediate and final evaluations. For each stage of the process parameters for assessment have been defined and methods identified. CONCLUSION: The combined experiences of French and British syndromic surveillance systems developed for use in deployed military forces has allowed the development of a specific evaluation framework. The tool is suitable for use by all nations who wish to evaluate syndromic surveillance in their own military forces. It could also be useful for civilian mobile systems or for national security surveillance systems.

Value of syndromic surveillance within the Armed Forces for early warning during a dengue fever outbreak in French Guiana in 2006.

BACKGROUND: A dengue fever outbreak occured in French Guiana in 2006. The objectives were to study the value of a syndromic surveillance system set up within the armed forces, compared to the traditional clinical surveillance system during this outbreak, to highlight issues involved in comparing military and civilian surveillance systems and to discuss the interest of syndromic surveillance for public health response. METHODS: Military syndromic surveillance allows the surveillance of suspected dengue fever cases among the 3,000 armed forces personnel. Within the same population, clinical surveillance uses several definition criteria for dengue fever cases, depending on the epidemiological situation. Civilian laboratory surveillance allows the surveillance of biologically confirmed cases, within the 200,000 inhabitants. RESULTS: It was shown that syndromic surveillance detected the dengue fever outbreak several weeks before clinical surveillance, allowing quick and effective enhancement of vector control within the armed forces. Syndromic surveillance was also found to have detected the outbreak before civilian laboratory surveillance. CONCLUSION: Military syndromic surveillance allowed an early warning for this outbreak to be issued, enabling a quicker public health response by the armed forces. Civilian surveillance system has since introduced syndromic surveillance as part of its surveillance strategy. This should enable quicker public health responses in the future.

Outbreak of malaria among policemen in French Guiana.

An outbreak of malaria occurred among 62 policemen following an operation against illegal gold panning in French Guiana. A retrospective cohort study was conducted. The objectives were to describe the outbreak and to identify factors related to the cases. The total number of initial cases was 37. Both Plasmodium falciparum and Plasmodium vivax were detected. Twenty-seven policemen presented with one to four recurrences. In bivariate analysis, factors related to malaria were a "medium to high" level of mosquito bites pollution at night, late washing in the evening and wearing a nonimpregnated Battle Dress Uniform (BDU). This investigation confirmed the low level of compliance with chemoprophylaxis among individuals on long-term assignment in French Guiana. Compliance with mosquito protection measures was satisfactory except for the use of impregnated BDU. Several recommendations were provided. Therefore, this outbreak reminds us that malaria remains a public health problem in French Guiana.

[Submitting studies without significant results]. / Faut-il tenter de publier une étude qui ne conclut rien?

When a study finds that no exposure factor or therapy is significantly related to a given effect, researchers legitimately wonder if the results should be submitted for publication and to what journal. Clinical trials that report significant associations have a higher probability of publication, a phenomenon known as selective publication. The principal reasons of this selective publication include author self-censorship, peer-reviewing, trials not intended for publication, interpretation of the p value, cost of journal subscriptions, and policies. Subsequent reviews and meta-analyses are biased by the unavailability of nonsignificant results. Suggestions for preventing this risk include university training, trial registries, an international standard randomised controlled trial number (ISRCTN), Cochrane collaboration, and the gray literature. Journals (including electronic journals) interested in studies with nonsignificant results are listed. New technologies are changing the relations between publishers, libraries, authors and readers.

[Current situation and future perspectives for malaria prophylaxis among travellers and military personnel]. / Situation actuelle et perspectives de la prophylaxie du paludisme chez le voyageur et dans les forces armées.

Malaria remains a major public health problem, both for travellers and for the 40,000 French soldiers deployed each year to endemic areas. Epidemiological data show that imported malaria (IM) is on the increase, and that migrants account for more than 60% of malaria cases notified each year in France. The increase in IM among French military personnel is explained by prematurely terminated chemoprophylaxis on return, repeated short missions, and more cases of P. vivax and P. ovale infection. The choice of chemoprophylaxis depends mainly on the level of chloroquine resistance in the country visited. The atovaquone-proguanil combination is well tolerated and only requires 7 days of intake on return from the endemic area. Doxycycline monohydrate is cheaper and better-tolerated than mefloquine, and is thus preferred for French military personnel. However, its short half-life necessitates very good compliance. Chemoprophylaxis should be combined with vector control measures and with personal protection (impregnated bednets, protective clothing, repellents, and indoor insecticide spraying). The need for these measures should be clearly explained before departure, during the stay, and after return.

[Marseilles, the Indian Ocean and Chikungunya virus]. / Marseille, l'Océan indien et le virus Chikungunya.

In recent decades Marseilles, through immigration, has become the largest Comorian city outside the archipelago. It is also home to a faculty of medicine that has made infectious diseases one of its fields of excellence. During the last two years, Marseilles has spearheaded the metropolitan French response to the Chikungunya crisis in the Indian Ocean region, and especially in the Reunion Island and Mayotte. Laveran military teaching hospital (Hôpital d'instruction des armées, HIA) has managed one of the largest metropolitan cohorts. Its teams have also reported the broad clinical spectrum of the disease in its later stages, and especially the high incidence of incapacitating tenosynovitis and distal arthritis, as well as the occurrence of a transient acrosyndrome during the second and third months in nearly one-quarter of patients. Importantly, they have also identified a mixed cryoglobulin in more than 90% of patients, the level of which matches clinical symptoms and is sensitive to systemic steroid therapy. This discovery opens the way to a better understanding of the pathophysiology of this viral disease. The Tropical Virology laboratory of the Tropical Medicine Institute of the Army health service (IMTSSA), which has close links with the national references center (CNRS) arbovirus laboratory, has developed new diagnostic tools, notably based on RT-PCR. Together with national reference center (CNRS), the laboratory produces and supplies antigens for Chikungunya serological tests in metropolitan France and overseas. It has taken into account the presence of cryoglobulins, which can lead to false-negative results in infected patients, and has considerably increased the diagnostic yield of serological techniques. The laboratory's fundamental research focuses on genomic characterization of viral variants isolated from humans and from the vector, and also on viral protease expression, for functional studies and antiviral candidate drug selection. The laboratory also collaborates with clinical teams in Reunion and metropolitan France working on humoral and cellular immune responses and on the different clinical forms of the disease. The Epidemiology and Public Health Department of IMTSSA conducted an epidemiological study of all gendarmes working in Reunion at the end of the epidemic (June 2006). This study, done in partnership with the tropical virology laboratory and CNRS, is helping to complete the clinical description of the epidemic, in an unbiased population. In 2007, it will form the basis for a prospective cohort study in which these patients will be monitored for several years to better document the chronic phase of the disease in a population with excellent healthcare access. Finally, the department has provided the civil authorities with advice and support in disease-control operations in Reunion. Communication played an important role in the management of this crisis, showing how crucial it now is for healthcare professionals to develop relevant skills. The Army Health Service in Maarseilles was never isolated from its university partners, as witnessed by clinical collaboration between Laveran HIA and CHU Nord (a Marseilles teaching hospital) and by virological cooperation between the IMTSSA and Etablissement français du sang (EFS) laboratories. This experience is highly encouraging with respect to the creation in Marseilles of a healthcare research network (RTRS) devoted to tropical and emerging infectious diseases.

Antibody responses to several malaria pre-erythrocytic antigens as a marker of malaria exposure among travelers.

Protective devices against vectors are used by travelers in malaria-endemic areas but their efficacy for protection against mosquitoes has rarely been evaluated. The level of exposure to malaria transmission of 205 soldiers deployed in Africa and the efficacy of their anti-vector prophylaxis was evaluated by comparison of their IgM and IgG responses against five pre-erythrocytic Plasmodium falciparum antigens (circumsporozoite protein, sporozoite threonine- and asparagine-rich protein, sporozoite- and liver-stage antigen, liver stage antigen 1, and SR11.1) before and at the end of their deployment, and three months after returning to France for 106 of these soldiers. The immune responses increased significantly during the mission in 35% (95% confidence interval = 28-42%) of the individuals. The permanent use of insecticide-treated bed nets and long-sleeve battle dress at night were associated with protective efficacy. The analysis of these antibody responses was sensitive enough to evaluate exposure to malaria transmission and the efficacy of anti-vector devices in travelers using antimalarial chemoprophylaxis.

Web services based syndromic surveillance for early warning within French Forces.

OBJECTIVES: Syndromic surveillance for early warning in military context needs a robust, scalable, flexible, ubiquitous, and interoperable surveillance system. METHODS: We have designed our surveillance system as a collaborative network of web services on the basis of a skill oriented decomposition of the overall task and a formal model of epidemiological events. RESULTS: The services (integration devices, epidemiologic receivers, information processing devices, GUI clients) are distributed in several locations in France and French Guiana using a secured network. CONCLUSIONS: This system is in operation since several months. It has already early detected two outbreaks before conventional surveillance systems.

[Epidemiology of malaria]. / Epidémiologie du paludisme.

Four parasite species, among which one lethal, at least 20 efficient vectors, spread on the most crowded and underdeveloped continents, where first antimalarials and insecticides were so extensively used for decades that they are now inefficient after resistances. It is today the sad medium on which malaria raged, spring of 1 million deaths and 300 millions cases a year, of which 90% in sub-Saharan Africa. In Africa, epidemiological patterns are widely different some to others, which explain unique control strategy failure and vanity. Waiting vaccines and new drugs, control must be centred on vectors control and multidrug therapy. France is the industrialised country with the highest number of imported cases (approximately equal to 7000 cases yearly), linked mainly to P. falciparum coming from sub-Saharan Africa and recurring in nearly 3/4 of cases in immigrants.