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.

Cryptosporidiosis outbreaks linked to the public water supply in a military camp, France.

INTRODUCTION: Contaminated drinking and recreational waters account for most of the reported Cryptosporidium spp. exposures in high-income countries. In June 2017, two successive cryptosporidiosis outbreaks occurred among service members in a military training camp located in Southwest France. Several other gastroenteritis outbreaks were previously reported in this camp, all among trainees in the days following their arrival, without any causative pathogen identification. Epidemiological, microbiological and environmental investigations were carried out to explain theses outbreaks. MATERIAL AND METHODS: Syndromic diagnosis using multiplex PCR was used for stool testing. Water samples (100 L) were collected at 10 points of the drinking water installations and enumeration of Cryptosporidium oocysts performed. The identification of Cryptosporidium species was performed using real-time 18S SSU rRNA PCR and confirmed by GP60 sequencing. RESULTS: A total of 100 human cases were reported with a global attack rate of 27.8%. Cryptosporidium spp. was identified in 93% of stool samples with syndromic multiplex PCR. The entire drinking water network was contaminated with Cryptosporidium spp. The highest level of contamination was found in groundwater and in the water leaving the treatment plant, with >1,000 oocysts per 100 L. The same Cryptosporidium hominis isolate subtype IbA10G2 was identified in patients' stool and water samples. Several polluting activities were identified within the protection perimeters of the water resource. An additional ultrafiltration module was installed at the outlet of the water treatment plant. After several weeks, no Cryptosporidium oocysts were found in the public water supply. CONCLUSIONS: After successive and unexplained gastroenteritis outbreaks, this investigation confirmed a waterborne outbreak due to Cryptosporidium hominis subtype IbA10G2. Our study demonstrates the value of syndromic diagnosis for gastroenteritis outbreak investigation. Our results also highlight the importance of better assessing the microbiological risk associated with raw water and the need for sensitive and easy-to-implement tools for parasite detection.

Lessons learned from the investigation of a COVID-19 cluster in Creil, France: effectiveness of targeting symptomatic cases and conducting contact tracing around them.

BACKGROUND: This study presents the methods and results of the investigation into a SARS-CoV-2 outbreak in a professional community. Due to the limited testing capacity available in France at the time, we elaborated a testing strategy according to pre-test probability. METHODS: The investigation design combined active case finding and contact tracing around each confirmed case with testing of at-risk contact persons who had any evocative symptoms (n = 88). One month later, we performed serology testing to test and screen symptomatic and asymptomatic cases again (n = 79). RESULTS: Twenty-four patients were confirmed (14 with RT-PCR and 10 with serology). The attack rate was 29% (24/83). Median age was 40 (24 to 59), and the sex ratio was 15/12. Only three cases were asymptomatic (= no symptoms at all, 13%, 95% CI, 3-32). Nineteen symptomatic cases (79%, 95% CI, 63-95) presented a respiratory infection, two of which were severe. All the RT-PCR confirmed cases acquired protective antibodies. Median incubation was 4 days (from 1 to 13 days), and the median serial interval was 3 days (0 to 15). We identified pre-symptomatic transmission in 40% of this cluster, but no transmission from asymptomatic to symptomatic cases. CONCLUSION: We report the effective use of targeted testing according to pre-test probability, specifically prioritizing symptomatic COVID-19 diagnosis and contact tracing. The asymptomatic rate raises questions about the real role of asymptomatic infected people in transmission. Conversely, pre-symptomatic contamination occurred frequently in this cluster, highlighting the need to identify, test, and quarantine asymptomatic at-risk contact persons (= contact tracing). The local lockdown imposed helped reduce transmission during the investigation period.

Incidence of leptospirosis in the French armed forces from 2004 to 2018: Retrospective analysis.

BACKGROUND: The French military personnel may be exposed to leptospirosis during their training or on duty on the field in continental France, and most of all, in intertropical areas in the French departments and in Africa. The aim of this study was to assess the incidence of leptospirosis from epidemiological surveillance and cases data from 2004 to 2018, and to propose tools to assess leptospirosis risk prior to any mission or leisure activity. METHOD: A retrospective epidemiological study on leptospirosis cases among French Armed Forces was conducted. More data were collected for 2 clusters in Martinique, as most of leptospirosis cases among French military personnel were identified in Martinique. RESULTS: Eighty-eight cases of leptospirosis were reported, 15 cases in continental France and 73 cases in overseas (including 42 cases in the French West Indies). The global leptospirosis incidence rate in continental France was 0.3/100,000 person-years and in overseas 24/100,000 person-years with the higher incidence rate in Martinique (99/100,000 person-years) and in Mayotte (36.9/100,000 person-years). For the clusters in Martinique, between January and June 2009, 7 cases were declared; between 2016 and 2018, 16 cases were reported, high proportions of severe cardiac, renal and neurological forms (6/16) and hospitalizations (9/16). CONCLUSION: The occupational risk is real in French Armed Forces, particularly in malaria-free intertropical areas where chemoprophylaxis by doxycycline is not applied. Prevention can be optimized by the use of practical tools such as tables and cartographies, leading to a better leptospirosis risk assessment and application of preventive recommendations.

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.

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.

Treatment interruption in HIV-positive patients followed up in Cameroon's antiretroviral treatment programme: individual and health care supply-related factors (ANRS-12288 EVOLCam survey).

INTRODUCTION: Decreasing international financial resources for HIV and increasing numbers of antiretroviral treatment (ART)-treated patients may jeopardise treatment continuity in low-income settings. Using data from the EVOLCam ANRS-12288 survey, this study aimed to document the prevalence of unplanned treatment interruption for more than 2 consecutive days (TI>2d) and investigate the associated individual and health care supply-related factors within the Cameroonian ART programme. METHODS: A cross-sectional mixed methods survey was carried out between April and December 2014 in 19 HIV services of the Centre and Littoral regions. A multilevel logistic model was estimated on 1885 ART-treated patients in these services to investigate factors of TI>2d in the past 4 weeks. RESULTS: Among the study population, 403 (21%) patients reported TI>2d. Patients followed up in hospitals reporting ART stock-outs were more likely to report TI>2d while those followed up in the Littoral region, in medium- or small-sized hospitals and in HIV services proposing financial support were at lower risk of TI>2d. The following individual factors were also associated with a lower risk of TI>2d: living in a couple, having children, satisfaction with attention provided by doctor, tuberculosis co-infection and not having consulted a traditional healer. CONCLUSIONS: Besides identifying individual factors of TI>2d, our study highlighted the role of health care supply-related factors in shaping TI in Cameroon's ART programme, especially the deleterious effect of ART stock-outs. Our results also suggest that the high proportion of patients reporting TI could jeopardise progress in the fight against HIV in the country, unless effective measures are quickly implemented like ensuring the continuity of ART supply.