Chikungunya Outbreak in Country with Multiple Vectorborne Diseases, Djibouti, 2019-2020.

During 2019-2020, a chikungunya outbreak occurred in Djibouti City, Djibouti, while dengue virus and malaria parasites were cocirculating. We used blotting paper to detect arbovirus emergence and confirm that it is a robust method for detecting and monitoring arbovirus outbreaks remotely.

Investigation of a COVID-19 outbreak on the Charles de Gaulle aircraft carrier, March to April 2020: a retrospective cohort study.

BackgroundSARS-CoV-2 emergence was a threat for armed forces. A COVID-19 outbreak occurred on the French aircraft carrier Charles de Gaulle from mid-March to mid-April 2020.AimTo understand how the virus was introduced, circulated then stopped circulation, risk factors for infection and severity, and effectiveness of preventive measures.MethodsWe considered the entire crew as a cohort and collected personal, clinical, biological, and epidemiological data. We performed viral genome sequencing and searched for SARS-CoV-2 in the environment.ResultsThe attack rate was 65% (1,148/1,767); 1,568 (89%) were included. The male:female ratio was 6.9, and median age was 29 years (IQR: 24-36). We examined four clinical profiles: asymptomatic (13.0%), non-specific symptomatic (8.1%), specific symptomatic (76.3%), and severe (i.e. requiring oxygen therapy, 2.6%). Active smoking was not associated with severe COVID-19; age and obesity were risk factors. The instantaneous reproduction rate (Rt) and viral sequencing suggested several introductions of the virus with 4 of 5 introduced strains from within France, with an acceleration of Rt when lifting preventive measures. Physical distancing prevented infection (adjusted OR: 0.55; 95% CI: 0.40-0.76). Transmission may have stopped when the proportion of infected personnel was large enough to prevent circulation (65%; 95% CI: 62-68).ConclusionNon-specific clinical pictures of COVID-19 delayed detection of the outbreak. The lack of an isolation ward made it difficult to manage transmission; the outbreak spread until a protective threshold was reached. Physical distancing was effective when applied. Early surveillance with adapted prevention measures should prevent such an outbreak.

COVID-19 outbreak among French firefighters, Marseille, France, 2020.

We investigated a COVID-19 outbreak at a fire station in Marseille, France. Confirmed cases were defined as individuals with positive SARS-CoV-2 reverse transcription (RT)-PCR and/or neutralising antibodies. All 85 firefighters at work during the outbreak period were included after questioning and sampled for RT-PCR and viral neutralisation assay. Twenty-three firefighters were confirmed positive, 19 of them were symptomatic, and four asymptomatic cases were confirmed by virus neutralisation. A total of 22 firefighters had specific neutralising antibodies against SARS-CoV-2. Neutralising antibodies were found in four asymptomatic and 18 symptomatic cases. Eleven symptomatic cases had high titres (≥ 1:80). The earliest detection of neutralising antibodies was 7 days after symptom onset, and 80% had neutralising antibodies 15 days after onset. One viral culture was positive 13 days after onset. The attack rate was 27%. We identified two introductions of the virus in this outbreak, through a presymptomatic and a paucisymptomatic case. Asymptomatic cases were not the source of a third generation of cases, although they worked without wearing a mask, indicating that asymptomatic cases did not play a significant role in this outbreak. Management and strategy based on early research of clinical signs associated with self-quarantine was effective.

Tracking Rift Valley fever: From Mali to Europe and other countries, 2016.

On 16 September 2016, the World Health Organization confirmed a Rift Valley fever (RVF) outbreak in Niger. Epidemiological surveillance was reinforced among the French Armed Forces deployed in Niger and bordering countries: Chad, Mali and Burkina Faso. On 26 October, a probable case of RVF was reported in a service member sampled in Mali 3 weeks earlier. At the time the result was reported, the patient was on vacation on Martinique. An epidemiological investigation was conducted to confirm this case and identify other cases. Finally, the case was not confirmed, but three suspected cases of RVF were confirmed using serological and molecular testing. RVF viral RNA was detectable in whole blood for 57 and 67 days after onset of symptoms for two cases, although it was absent from plasma and serum. At the time of diagnosis, these cases had already returned from Mali to Europe. The infectivity of other arboviruses in whole blood has already been highlighted. That RVF virus has been detected in whole blood that long after the onset of symptoms (67 days) raises the question of its potential prolonged infectivity. Because of exposure to tropical infectious diseases during deployment, military populations could import emerging pathogens to Europe.

Histamine food poisoning: a sudden, large outbreak linked to fresh yellowfin tuna from Reunion Island, France, April 2017.

On 20 April 2017, an outbreak of histamine food poisoning occurred in a French military unit located near Paris. A total of 40 cases were identified (attack rate: 16.6%). We conducted a case-control study on 31 cases and 63 controls. Multivariate analysis pointed to cooked yellowfin tuna fillet as the very likely source of food poisoning (odds ratio = 156.8; 95% confidence interval: 18.4-1,338.4). The fresh yellowfin tuna was from Reunion Island and was supplied vacuum-sealed and packed with ice at the principal food market of Paris. No cold chain issues could be established in the upstream and downstream supply chains. Histamine concentration was found to be 1,720 mg/kg in leftover raw tuna, and 3,720 mg/kg in control cooked tuna, well above the threshold limit values defined by European regulations (200 mg/kg). The presence of Klebsiella variicola and Pantoea agglomerans, microorganisms of the Enterobacterales order that have been reported to produce histamine, was confirmed in the leftover raw tuna. This type of food poisoning is rarely recognised and confirmed. We describe the outbreak to highlight the specific key points of this type of investigation.

Monitoring of returnees from Ebola-affected areas: lessons learned based on the experience of French armed forces deployed in Guinea, 2015.

Introduction: During the 2014-15 Ebola virus disease (EVD) outbreak in West Africa, French armed forces were involved in the treatment and management of Ebola patients in Guinea. The constant flow of military personnel returning from their deployment posed a risk of secondary dissemination of the Ebola virus. Our objective was to describe the follow-up of returning service members that was implemented to prevent this risk of dissemination in France. Method: For the French military, a specific complementary follow-up was added to the national monitoring to take into account the need for a detailed record for follow-up of returning military personnel and to keep the military chain of command informed. Results: All the 410 service members deployed in Guinea underwent monitoring among whom 22 were suspected of EVD. Three of them were considered as possible EVD cases but none of them was tested positive for EVD. Conclusion: The monitoring organized for French service members deployed in Guinea made it possible to follow all exposed military personnel after their return, know their health status on a near real-time basis and be aware of all alerts. To reach this goal the collaboration with French national health agencies was necessary and should be improved in the future.

Epidemiological and entomological studies of a malaria outbreak among French armed forces deployed at illegal gold mining sites reveal new aspects of the disease's transmission in French Guiana.

BACKGROUND: In December 2010, a Plasmodium vivax malaria outbreak occurred among French forces involved in a mission to control illegal gold mining in French Guiana. The findings of epidemiological and entomological investigations conducted after this outbreak are presented here. METHODS: Data related to malaria cases reported to the French armed forces epidemiological surveillance system were collected during the epidemic period from December 2010 to April 2011. A retrospective cohort study was conducted to identify presumed contamination sites. Anopheles mosquitoes were sampled at the identified sites using Mosquito Magnet and CDC light traps. Specimens were identified morphologically and confirmed using molecular methods (sequencing of ITS2 gene and/or barcoding). Anopheles infections with Plasmodium falciparum and P. vivax were tested by both enzyme-linked immunosorbent assay and real-time PCR. RESULTS: Seventy-two P. vivax malaria cases were reported (three were mixed P. falciparum/P. vivax infections), leading to a global attack rate of 26.5% (72/272). Lack of compliance with vector control measures and doxycycline chemoprophylaxis was reported by patients. Two illegal gold mining sites located in remote areas in the primary forest were identified as places of contamination. In all, 595 Anopheles females were caught and 528 specimens were formally identified: 305 Anopheles darlingi, 145 Anopheles nuneztovari s.l., 63 Anopheles marajoara and 15 Anopheles triannulatus s.l. Three An. darlingi were infected by P. falciparum (infection rate: 1.1%) and four An. marajoara by P. vivax (infection rate: 6.4%). DISCUSSION: The main drivers of the outbreak were the lack of adherence by military personnel to malaria prevention measures and the high level of malaria transmission at illegal gold mining sites. Anopheles marajoara was clearly implicated in malaria transmission for the first time in French Guiana. The high infection rates observed confirm that illegal gold mining sites must be considered as high level malaria transmission areas in the territory. CONCLUSIONS: Illegal gold mining activities are challenging the control of malaria in French Guiana. Collaboration with neighbouring countries is necessary to take into account mobile populations such as gold miners. Malaria control strategies in the French armed forces must be adapted to P. vivax malaria and sylvatic Anopheles species.

Acute acoustic trauma in the French armed forces during 2007-2014.

CONTEXT: Despite existing preventive measures, the number of acute acoustic trauma (AAT) cases reported to the French Military Epidemiological Surveillance System (MESS) remains high. AIMS: The objective of this study was to describe AAT and the preventive measures already implemented. SUBJECTS AND METHODS: We conducted a descriptive cross-sectional analysis of AAT using data from the MESS for the period 2007-2014. In addition, we reviewed the current prevention measures that exist in the French armed forces. STATISTICAL ANALYSIS USED: Comparisons between different incidence rates were made by Poisson and quasi-Poisson regression. RESULTS: Between 2007 and 2014, 10,487 AAT cases were reported to the MESS, with a significant decrease in 2013 (P < 0.001). AAT incidence rates were the highest among those aged <25 years - 14.3 per 1000 person-years (PYs) (P < 0.001), and those in the army; with 8.1 per 1000 PYs (P < 0.001), and men had almost twice the risk of women (P < 0.001). AAT mainly occurred in training schools or at camps during exercises. The main prevention actions identified were the following: official regulations, education, making hearing protection devices (HPDs) available for all service members, and regular hearing monitoring. A working group has been set up and has proposed an informative chapter in the weapon handling instruction book, an AAT simulator, and a new HPD, the 3M® earplug, with an information brochure. CONCLUSIONS: AAT rates decreased from 2007 to 2014 in the French armed forces. Further analysis is needed to identify the underlying factors involved to improve the prevention actions proposed. The MESS and targeted surveys will assess the impact of the different prevention measures implemented.

From Foodborne Disease Outbreak (FBDO) to Investigation: The Plant Toxin Trap, Brittany, France, 2018.

On 6 July 2018, the Center for Epidemiology and Public Health of the French Armed Forces was informed of an outbreak of acute gastroenteritis among customers of a dining facility at a military base in Brittany, France. A total of 200 patients were reported out of a population of 1700 (attack rate: 12%). The symptoms were mainly lower digestive tract disorders and occurred rapidly after lunch on 5 July (median incubation period: 3.3 h), suggesting a toxin-like pathogenic process. A case-control survey was carried out (92 cases and 113 controls). Statistical analysis pointed to the chili con carne served at lunch on 5 July as the very likely source of poisoning. Phytohaemagglutinin, a plant lectin, was found in the chili con carne at a concentration above the potentially toxic dose (400 HAU/gram). The raw kidney beans incorporated in the chili con carne presented a high haemagglutination activity (66,667 HAU/gram). They were undercooked, and the phytohaemagglutinin was not completely destroyed. FBDOs due to PHA are poorly documented. This study highlights the need to develop methods for routine testing of plant toxins in food matrices. Improved diagnostic capabilities would likely lead to better documentation, epidemiology, and prevention of food-borne illnesses caused by plant toxins.

Mortality among active-duty male French Armed Forces, 2006-10.

BACKGROUND: In the Armed Forces, knowledge about the causes of deaths is required in order to develop prevention strategies. This study presents the main characteristics of causes of deaths among male active-duty personnel in the French Armed Forces during the 2006-10 period and compares them with the general French male population. METHODS: The data are provided by military public health surveillance. Comparisons of the specific mortality rates (MR) were performed using a Poisson regression. Standardized mortality ratios (SMRs) were calculated to compare mortality with the general French male population. RESULTS: There were 1455 deaths among male active-duty personnel during the study period [MR: 100.9 per 100,000 person-years (PY); 95% confidence interval 95.7-106.1]. The 17-24 age group was characterized by violent deaths: transport accident (MR: 45.9 per 100,000 PY) and suicide (18.8 per 100 000 PY). Overall SMRs show significantly lower MR compared with the French national MR with the exception of SMR for transport accident and suicide in the 17-24 age group. CONCLUSIONS: There is a significantly lower deficit of mortality compared with the French male general population, reflecting a strong healthy worker effect. However, health promotion programmes should continue to put emphasis on transport accident especially among the 17-24 age group.

Emergence of Indian lineage of ECSA chikungunya virus in Djibouti, 2019.

The chikungunya virus (CHIKV) originated from Africa and has spread worldwide. Since 2017, multiple chikungunya outbreaks have been reported in the Horn of Africa, without molecular characterization. In November 2019, an autochthonous acute chikungunya infection was diagnosed in a French patient living in Djibouti, marking the re-emergence of the virus in the country. The strain was isolated and fully sequenced. Phylogenetic analysis revealed that the Djiboutian strain belongs to the Indian lineage of the Eastern/Central/South African (ECSA) genotype. Two mutations highly increasing the virus's fitness in Aedes aegypti, the sole vector present in Djibouti city, were identified.

Prevalence of unsafe sex with one's steady partner either HIV-negative or of unknown HIV status and associated determinants in Cameroon (EVAL ANRS12-116 survey).

OBJECTIVE: Our study aimed at estimating the prevalence of inconsistent condom use and at identifying its determinants in steady partnerships among people living with HIV/AIDS (PLWHA) in Cameroon. METHODS: Analyses were based on data collected during the national cross-sectional multicentre survey EVAL (ANRS 12-116), which was conducted in Cameroon between September 2006 and March 2007 among 3151 adult PLWHA diagnosed HIV-positive for at least 3 months. The study population consisted of the 907 survey participants who reported sexual activity during the previous 3 months, with a steady partner either HIV-negative or of unknown HIV status. Logistic regression was used to identify factors associated with individuals' report of inconsistent condom use during the previous 3 months. RESULTS: Inconsistent condom use was reported by 35.3% of sexually active PLWHA. In a multivariate analysis adjusted for socio-demographic characteristics, not receiving antiretroviral therapy (OR (95% CI): 2.28 (1.64 to 3.18)) was independently associated with inconsistent condom use. CONCLUSIONS: The prevalence of unsafe sex remains high among sexually active PLWHA in Cameroon. Treatment with antiretroviral therapy is identified as a factor associated with safer sex, which further encourages the continuation of the national policy for increasing access to HIV treatment and care, and underlines the need to develop counselling strategies for all patients.

Determinants of unplanned antiretroviral treatment interruptions among people living with HIV in Yaoundé, Cameroon (EVAL survey, ANRS 12-116).

OBJECTIVE: To identify correlates of self-reported antiretroviral therapies (ART) interruptions among people living with HIV and AIDS (PLWHA) in Cameroon. METHODS: Analyses were based on data collected in the national survey EVAL (ANRS 12-116) among 533 ART-treated PLWHA in Yaoundé, the capital city of Cameroon, and its neighbourhood. Logistic regression models were used to identify factors associated with self-reported ART interruptions longer than two consecutive days during the previous 4 weeks. RESULTS: ART interruptions were reported by 68 patients (12.8%). After adjustment for gender, education and household income, characteristics independently associated with interruptions were pharmacy stock shortages [OR (95%CI):3.25 (1.78-5.90)], binge drinking [2.87 (1.39-5.91)] and the number of self-reported slimming symptoms [1.23 (1.02-1.48)]. CONCLUSION: In poor-resource settings where access to second and third-line regimens is still limited, food supply programs and interventions to minimise ART shortage may reduce the risk of ART interruptions.

Dengue surveillance in the French armed forces: a dengue sentinel surveillance system in countries without efficient local epidemiological surveillance.

Surveillance of travel-acquired dengue could improve dengue risk estimation in countries without ability. Surveillance in the French army in 2010 to 2011 highlighted 330 dengue cases, mainly in French West Indies and Guiana: DENV-1 circulated in Guadeloupe, Martinique, French Guiana, New Caledonia, Djibouti; DENV-3 in Mayotte and Djibouti; and DENV-4 in French Guiana.

Adverse events following pandemic influenza vaccine Pandemrix® reported in the French military forces--2009-2010.

BACKGROUND: In the face of the A(H1N1) 2009 influenza pandemic, in October 2009 the French military health service (SSA) initiated a large vaccination campaign with Pandemrix(®) vaccine in the military forces. The aim of this study was to describe vaccine adverse events (VAE) reported during this campaign. METHODS: VAE and the number of people vaccinated were surveyed by the SSA Epidemiological network across all military forces during the campaign, from October 2009 to April 2010. For each case, a notification form was completed, providing patient and clinical information. Three types of VAE were considered: non-serious, serious and unexpected. RESULTS: There were 315.4 reported VAE per 100,000 vaccinations. Vaccination and VAE incidence rate peaks coincided with influenza epidemic peak in early December. The number of injected doses was 49,138, corresponding to a 14.5% vaccination coverage among military personnel, and 155 VAE were reported, including 5 serious VAE (1 Guillain-Barre syndrome, 2 malaises and 1 convulsive episode). Most VAE were non-serious (97.1%). Among these, 6 cases of local, rapidly regressive paresthesia were observed. DISCUSSION: The military VAE surveillance system constitutes the only observatory on benign VAE in France. The reporting rate was much higher after the pandemic vaccine than after the seasonal vaccine, which may be a reflection of stimulated reporting. This report provides a useful description of VAE among military personnel during a mass emergency vaccination program, showing that the tolerance of the pandemic vaccine appeared acceptable.

Illness in French travelers to Senegal: prospective cohort follow-up and sentinel surveillance data.

OBJECTIVE: To investigate travel-associated illnesses in French travelers to Senegal. METHODS: A prospective cohort follow-up was conducted in 358 travelers recruited at a pre-travel visit in Marseille and compared to data from ill travelers collected from the GeoSentinel data platform in two clinics in Marseille. RESULTS: In the cohort survey, 87% of travelers experienced health complaints during travel, which most frequently included arthropod bites (75%), diarrhea (46%), and sunburns (36%). Severe febrile illness cases, notably malaria and salmonella, were detected only through the surveillance system, not in the cohort follow-up. Food hygiene was inefficient in preventing diarrhea. Arthropod bites were more frequent in younger patients and in patients with pale phototypes. Sunburns were also more frequent in younger patients. Finally, we demonstrate that mild travel-related gastrointestinal symptoms and the lack of arthropod bites are significantly associated with poor observance of antimalarial prophylaxis. CONCLUSIONS: In this study, we suggest the complementary nature of using cohort surveys and sentinel surveillance data. Effective protection of skin from arthropod bites and sun exposure should result in significantly reduced travel-associated diseases in Senegal. Travelers to Senegal should be informed that diarrhea is extremely common despite preventive measures, but it is mild and transitory and should not lead to the disruption of malaria chemoprophylaxis.

Gastrointestinal illnesses among French forces deployed to Djibouti: French military health surveillance, 2005-2009.

Despite an increase in foreign tourism and in the numbers of foreign military personnel deployed to Djibouti, little is known about the risk of gastrointestinal illness in this country in eastern Africa. To assess risk and to describe common features of gastrointestinal illnesses, reports of illness derived from military health surveillance data collected during 2005-2009 among French service members deployed to Djibouti were reviewed. Diarrhea was the most common problem; it had an annual incidence ranging from 260 to 349 cases per 1,000 person-years. The risk was higher among soldiers deployed short-term (four months) than among soldiers deployed long-term (two years). This five-year review of French health surveillance data documents a significant burden of diarrhea among French soldiers in Djibouti. The identification of factors associated with risk may permit efficient targeting of interventions to reduce morbidity from gastrointestinal illness.