[Covid-19 and the animal world, from a still mysterious origin towards an always unpredictable future]. / Rapport 21-11. Covid-19 et monde animal, d'une origine encore mystérieuse vers un futur toujours incertain.

Although the emergence of Covid-19 in China has not been clearly elucidated, the hypothesis of an animal origin remains the most likely. It is supported by the presence of the horseshoe bat suspected to be the progenitor of SARS-CoV-2 and by the scarcity of pork, due to African swine fever, diverting consumers to exotic animals of breeding sold in the markets. During this pandemic, several animal species were affected by SARS-CoV-2. Sporadic cases were first reported in pets (dogs and cats) infected by their owners, then in large feline species and apes infected in zoos by their nurses. The most significant human-to-animal transmission has occurred in mink farms, especially in the Netherlands and Denmark, requiring the euthanasia of several million animals, with mink in turn having contaminated men and stray or nomadic cats. The study of natural or experimental transmissions of SARS-CoV-2 has made it possible to identify the most receptive animal species: American minks and raccoon dogs, and to a lesser extent stray or nomadic cats, which could become an animal reservoir due to their sensitivity to this virus and their extending prolificacy. The European Commission decided on May 17, 2021 to strengthen the surveillance of SARS-CoV-2 infections in minks and other mustelids, as well as in raccoon dogs, highlighting stressing that the epidemiological assessment of the risk presented by the he appearance of SARS-CoV-2 in these susceptible species was a public health priority.

Tuberculosis in Laos, who is at risk: the mahouts or their elephants?

SUMMARY Tuberculosis (TB) in elephants has the potential to infect humans and is an increasing public health concern. Lao PDR is one of the last countries where elephants are still used for timber extraction and where they live in close contact with their mahouts. There are 500 animals at work in the country, some interacting with wild herds. Although human TB prevalence is known to be high in Laos, studies on elephant TB had yet to be undertaken. From January to July 2012, screening was performed using the ElephantTB Stat-Pak assay on 80 elephants working around the Nam Pouy National Park in Sayaboury Province. This represents more than 18% of the total registered national working elephant population. Here we report that 36% of the elephants were seroreactive to the test. Of these, 31% had contacts with wild individuals, which suggests potential transmission of mycobacteria to the local wild herds. Clinical examination, chest X-rays, sputum microscopy and culture were performed on their 142 mahouts or owners. Despite high TB seroreactivity in elephants, no participant was smear- or culture-positive for Mycobacterium tuberculosis or M. bovis, although atypical mycobacteria were isolated from 4% of participants.

[Acceptability of vaccination against human papillomavirus (HPV) by pediatricians, mothers and young women in Ho Chi Minh City, Vietnam]. / Acceptabilité de la vaccination contre les papillomavirus humains (HPV) par les pédiatres, les mères et les jeunes femmes à Hô Chi Minh Ville, Vietnam.

BACKGROUND: Cervical cancer (CC) is almost always induced by some oncogenic types of human papillomavirus (HPV). In Vietnam, it is the first leading cause of cancer in women, with highest prevalence in Ho Chi Minh City (HCMC). Since 2006, prevention of the CC has been improved by licensure of recombinant vaccines directed against HPV 16 and 18, effective when administered before the age of first sexual intercourse. A national program for routine immunization of pre-adolescent girls in addition to cytological screening of adult women would greatly reduce the impact of CC in Vietnam but vaccines remain expensive and it is unclear how this strategy would be accepted by the target population. The aim of this study was to assess the acceptability of HPV vaccination by pediatricians, mothers with a daughter aged 9-15 years and young women aged 16-26 years in HCMC. METHODS: Between March and June 2010, a cross-sectional survey of knowledge and attitudes was administered to 115 pediatricians in the pediatric hospital, 210 mothers and 400 young women attending the gynecology department of the University Hospital. RESULTS: Pediatricians generally had a good perception of the risk but they still lacked knowledge about HPV vaccination, given by 66% of them. Among mothers, 18% knew the relationship between HPV infection and CC, 43% had heard of HPV vaccination and 40% agreed to vaccinate their daughter. Among young women, 35% knew the risk, 49% knew the vaccine and 38% wanted to be vaccinated. Level of education, amount of income and celibacy were positively related to intention to be vaccinated. The lack of information on HPV vaccination and the high cost of vaccines were the main causes of refusal or indecision. CONCLUSION: Routine HPV vaccination of girls in HCMC will be well accepted by the population if a large campaign of health education is implemented by the government and if the affordability of vaccines is facilitated.

Interaction between vestibulo-spinal and corticospinal systems: a combined caloric and transcranial magnetic stimulation study.

We investigated the interaction between vestibular and corticospinal stimuli in 8 healthy volunteers. Vestibular stimulation was induced with unilateral ear caloric irrigation (30°C) with subjects supine. Single transcranial magnetic stimulation (TMS) pulses were delivered (double-cone coil, intensities 60-75% maximal output) every 10-20 s during vestibular activation and during baseline. Bilateral surface electromyography (EMG) from splenius capitis, sternocleidomastoid (SCM), obliquus externus abdominis, vastus lateralis, biceps femoris (BF), tibialis anterior and peroneus longus was obtained. During whole-body maximal rotatory voluntary isometric contraction (MRVC), only SCM and BF displayed EMG activation/inhibition patterns indicating axial rotatory action. TMS-induced motor evoked potentials (MEPs) after caloric irrigation revealed that only SCM showed consistent vestibular-mediated excitation/inhibition responses, i.e. an increase in MEP area contralateral to the irrigation and a decrease in MEP area ipsilaterally (+12.7 and -6.3% of the MRVC, respectively). A putative head turn induced by this SCM activity pattern would be in the same direction of the slow-phase eye movement. EMG in the 100 ms preceding TMS showed muscle tone values of approximately 10% of MRVC. After caloric irrigation, these values increased by ca. 2% for all muscles bilaterally and hence cannot explain the direction-specific SCM MEP changes. Thus, SCM MEPs show caloric-induced amplitude modulation indicating that SCM is under both horizontal semicircular canal and corticospinal control. This vestibular modulation of corticospinal SCM control likely occurs at cortical levels. The direction of the MEP modulation indicates a directional coupling between vestibularly induced head and eye movements.

[Increase of entomological indices during the pre-epidemic period of dengue in Ben Tre, South Vietnam]. / Augmentation des indices vectoriels en période pré-épidémique de dengue à Ben Tre, Sud Vietnam.

Dengue has emerged in Vietnam 50 years ago and since has become endemo-epidemic throughout the whole country. Each year, major epidemics of dengue fever (DF) and dengue hemorrhagic fever (DHF) hit South Vietnam during the rainy season, causing significant morbidity and mortality, especially among young children. The only preventive measure is vector control, but it is often implemented too late or indiscriminately. The aim of this study was to investigate, in the pre-epidemic stage, the existence of significant changes in vector indices, which will predict DF/DHF outbreaks. We conducted a descriptive transversal study, repeated once a month for four months (March to June) in the village of Locthuan (province Ben Tre) in the Mekong's delta. Adult mosquitoes were caught in 30 houses, and larvae were collected in water holding containers of 50 houses. The houses were randomly selected. Vector densities were calculated according to the indices recommended by WHO. Virological analysis was carried out on lots of female Aedes and larvae in order to determine viral infection rates. Catches of adult mosquitoes collected 496 specimens including 329 Aedes, 139 Culex and 28 Anopheles. Aedes aegypti was present in 63% of visited homes that is an average density of 1.8 mosquitoes per house. The increase in imaginal indices during the 4 months was not significant. The survey of breeding sites of Ae. aegypti identified 1292 water containers in which 71,569 larval specimens were collected. The values of house index, container index [CI] and Breteau index [BI] increased each month, the latter from 166 to 442. This increase was significant for CI and BI. Breeding sites were mostly intra-home, mainly consisting of large and small ceramic jars. Larval density of Ae. aegypti in the containers also increased significantly over the 4 months. It was correlated with the lack of cover and predators such as Mesocyclops spp., Micronecta spp. and larvivorous fishes. Cultivation of 15 pools of 10 adult females and 29 pools of larvae (ie 1088 specimens) of Ae. aegypti failed to isolate dengue virus. The high Stegomyia indices measured in this South Vietnamese village and their increase before the rainy season reflect a situation at high risk of epidemics but cannot predict the occurrence of an outbreak in the absence of virus isolation from mosquitoes. They justify conducting an integrated vector control throughout the year.

From outbreak detection to anticipation.

BACKGROUND: Bioterrorist threats and the emergence of new infectious pathogens force structures and means dedicated to outbreaks detection to evolve. Obtaining early information is becoming a major stake. Development of early warning system and new epidemiological tools open new perspectives in real time management of outbreaks. METHODS: Through several examples, this overview presents a synthesis and reports the recent multidisciplinary evolutions, which occurred in the field of outbreak detection and information useful for outbreaks anticipation. CONCLUSION: Outbreak detection is a multidisciplinary activity which relies on many protean epidemiologic sensors. Detection should not be perceived as a finality, but as a crucial step of a broader process in outbreak management (detection, alarm, alert, acceptability, implementation of countermeasures or not). That is why the evaluation of a monitoring system should not be limited to only its ability to detect an aberration. Today, progress in biology, modeling, remote sensing and environmental detection allow model development with anticipation aiming.

[Asia: avian influenza H5N1]. / La grippe H5N1.

The emergence of the first human cases of avian influenza in Hong Kong in 1997 has raised fears of a new pandemic originating from the Asian continent. Despite unprecedented international mobilization, first to stop then to limit its diffusion, the highly pathogenic avian virus A/H5N1 has successfully spread in Asia, Europe and Africa by successive epizootic outbreaks affecting migratory birds and poultry, Transmission from animals to humans is uncommon but severe with a fatality rate exceeding 60% in confirmed cases. Nearly half of the countries struck by the disease is in Asia. With 87% of confirmed cases and 91% of deaths, Asia is also one of the continent most heavily affected. Like the neighbouring countries in South-East Asia, Cambodia has been repeatedly hit by avian flu in the recent years. The measures implemented to prevent the spread of A/H5N1 virus in farms, to improve the behaviour of farmers and to clean up the poultry markets emphasize the multiple difficulties to control this zoonosis. Meanwhile, influenza surveillance is being carried out in humans, based on a reporting system and a network of sentinel hospitals connected to the Institut Pasteur du Cambodge. Thus, Cambodia takes an active part in the wide international network which should quickly detect any mutational event among avian flu viruses that might lead to the emergence of a pandemic.

[These infectious diseases imported with food]. / Ces maladies infectieuses importées par les aliments.

People are sometimes frightened by food scares and foodstuffs are increasingly suspected of containing dangerous substances or infectious agents, as a result of the unprecedented development of the industry and food trade in the world. Rightly or wrongly, imported food is held responsible for the greatest risks. Importing an infectious disease along with food can be a source of danger, involving multiple agents, mainly bacterial (Salmonella, Campylobacter, Verotoxin producing Escherichia coli, Listeria...), but also parasitic (Toxoplasma gondii, Cyclospora cayetanensis, Trichinella spp...), and viral (Norovirus, hepatitis A virus), as well as non conventional communicable agents and mycotoxins. Prevention of food risks means enforcing international regulations on the part of the 149 member states of the WTO, increasing vigilance with regard to illegal imports of food, systematically investigating collective food-borne outbreaks, and finally implementing controls according to the hazard analysis and critical control point (HACCP) method.

[Effectiveness of triennial anti-influenza vaccination in French military during the 2003-2004 influenza season]. / Evaluation de l'efficacité clinique de la vaccination antigrippale triennale dans les armées (saison 2003-2004).

BACKGROUND: Influenza may rapidly disseminate within populations living in confined settings, causing considerable morbidity and disrupting daily activities. The French military health-care system set up since 1994 a prevention strategy based on triennial anti-influenza vaccination. The aim of this study was to evaluate the effectiveness of this strategy during the 2003-2004 influenza season. METHODS: We conducted a matched case-control study from 10/01/2003 through 3/31/2004. Cases were laboratory-confirmed influenza cases. The controls were not to have presented influenza during all the period of study. Controls were matched to cases by sex, army unit and age. Subgroups were categorized into four groups by vaccination regimen [0-1 year], [1-2 years], [2-3 years], [3 years and more or unvaccinated]. RESULTS: One hundred and eighteen cases and 435 controls were included. The proportion of correctly vaccinated subjects (

[Control of Opisthorchis viverrini infection for cholangiocarcinoma prevention]. / Vaincre la distomatose à Opisthorchis viverrini pour prévenir le cholangiocarcinome.

The International Agency for Research on Cancer (IARC) has classified two liver flukes as carcinogenic to humans (Group 1): Opisthorchis viverrini in 1994 and Clonorchis sinensis in 2009. This review is focused on O. viverrini, the most studied of these two trematodes, which infects nearly 10 million people in Southeast Asia. The life cycle involves two intermediate hosts living in fresh water: a snail of the genus Bithynia and a ciprinid fish. The definitive hosts (human, cat, dog) become infected by ingesting raw fish containing metacercariae, the infective stage of the parasite. Adult flukes attach to the epithelium of the bile ducts where they feed for as long as 10 to 30 years, resulting in chronic inflammation, epithelial hyperplasia, periductal fibrosis and formation of granuloma. For a long asymptomatic, the distomatosis is revealed by a chronic cholangitis when the parasite load becomes high. Complications can occur with time: gallstones, cholangitis, liver abscess, pancreatitis and, after a few decades, cholangiocarcinoma (CCA). The epidemiological correlation between the prevalence of O. viverrini infection and the incidence of CCA has been demonstrated in the northeast of Thailand. Specifically, the Khon Kaen province has the highest incidence rate in the world. The CCA can develop asymptomatically for a long time, especially in intrahepatic locations. It is often discovered at a late stage, unresectable. Its prognosis is dreadful with a survival rate less than 5% at 5 years. The phenomenon of carcinogenesis induced by O. viverrini is multifactorial. It has been specially studied using experimental infection on the Syrian golden hamster. Three intricated mechanisms are involved: (i) the direct damage caused by adult worms on the bile duct epithelium, (ii) the immunopathologic processes related to chronic inflammation (oxidative stress) and (iii) the mitogenic and anti-apoptotic effects of the proteins secreted by the parasite. Exogenous cofactors are also involved, such as nitrosamines in fish-based dishes undercoocked or fermented, very popular in these endemic regions. Despite the effectiveness of praziquantel to successfully cure this distomatose, opisthorchiasis persists endemic in areas where the incidence of CCA tends to progress. Mass deworming campaigns are ineffective due to the frequency of reinfection in the exposed population. Repeating alternatively cures and reinfections may promote carcinogenesis. The failure of prevention programs reflects the difficulty of changing the traditional habits of consuming raw or fermented fish. Pending a vaccine prophylaxis, control strategies are based on integrated measures involving the treatment of reservoir hosts, sanitation and efforts of continuing information and education to deter the consumption of uncooked fish and to improve the sanitation in rural areas.

Burkholderia pseudomallei in a lowland rice paddy: seasonal changes and influence of soil depth and physico-chemical properties.

Melioidosis, a severe infection with the environmental bacterium Burkholderia pseudomallei, is being recognised increasingly frequently. What determines its uneven distribution within endemic areas is poorly understood. We cultured soil from a rice field in Laos for B. pseudomallei at different depths on 4 occasions over a 13-month period. We also measured physical and chemical parameters in order to identify associated characteristics. Overall, 195 of 653 samples (29.7%) yielded B. pseudomallei. A higher prevalence of B. pseudomallei was found at soil depths greater than the 30 cm currently recommended for B. pseudomallei environmental sampling. B. pseudomallei was associated with a high soil water content and low total nitrogen, carbon and organic matter content. Our results suggested that a sampling grid of 25 five metre square quadrats (i.e. 25 × 25 m) should be sufficient to detect B. pseudomallei at a given location if samples are taken at a soil depth of at least 60 cm. However, culture of B. pseudomallei in environmental samples is difficult and liable to variation. Future studies should both rely on molecular approaches and address the micro-heterogeneity of soil when investigating physico-chemical associations with the presence of B. pseudomallei.

[Impact and forecasting of hepatitis A immunization in French armed forces, 1990-2004]. / Impact et modélisation des effets attendus de la stratégie de vaccination contre les hépatites A chez les militaires français, 1990-2004.

BACKGROUND: Hepatitis A is a public health problem specially for migrants or travellers from industrialized countries with a low hepatitis A endemic level. French armed forces adopted an immunization strategy which first targeted overseas forces and subsequently was extended to all armed forces. In this work we studied the impact of this policy. METHODS: Epidemiological surveillance data from 1990 to 2004 was analyzed by Poisson regression and exponential models of decrease used to forecast future rates. RESULTS: From the 826 cases of hepatitis A reported during the study period, 266 (32.2%) occurred in overseas forces and 560 (67.8%) in forces stationed in France. Three periods could be identified in the decline of annual incidence: before 1994, with an average rate of 23.2 per 100,000; from 1994 to 1998: 10.2; and after 1998: 1.2 for all French armed forces. For overseas armed forces, the average rate was 117 per 100,000 before 1994 and 17.1 from 1994 to 1998 (p<0.001). For armed forces stationed in France, the average rate was 12.2 per 100,000 before 1998 and 0.9 after (p<0.001). For overseas armed forces, models clearly described the declining incidence subsequent to targeted immunization in 1995 and for armed forces stationed in France, the decline with generalized immunization starting in 1998. DISCUSSION: The impact of immunization against hepatitis A virus was significant both in an overseas population and in a population staying in France where the risk level can be considered low due to the low endemic rate in France. These results suggest that immunization should be proposed not only for travellers but also for the general population based on real knowledge of the situation and cost-effectiveness analyses.

[Place of surgery in the prevention of recurrences of digestive haemorrhages at the patients presenting a portal hypertension due to Schistosoma mekongi]. / Place de la chirurgie dans la prévention des récidives d'hémorragies digestives chez les sujets présentant une hypertension portale due a Schistosoma mekongi.

In spite of a decrease of the prevalence of hepato-splenic schistosomiasis thanks to mass-treatment with Praziquentel from December 1994 till now (CNM - MSF - WHO - Health Provincial Director) of target-populations in Kratie Province, severe cases of portal hypertension are not exceptional (digestive bleedings, after rupture of oesophageal varices). Out of 106 cases of portal hypertension: alI patients have had clinical survey biological tests (liver function, haematology and serology). Most of them had ultrasonography (Aloka 55,500 Sound 3.5 MHz). Nearly half of the group of 153 patients has never had bleedings. More than 45 were not eligible for surgery for different reasons: severe anaemia (few possibilities for massive transfusion in Cambodia), serology (S. mekongi) + but also hepatitis B or C +, hepatic biological exams (hepatic insufficiency). So we decided for eleven of them to use a surgical decompression procedure in order to decrease portal hypertension and the porto-systemic gradient. After defining portal hypertension, specific clinical features of portal hypertension (secondary to Schistosomiasis) the authors report eleven cases who were operated on (2000-2002): 4 mesenterico-cave shunt with interposition of a graft (Drapanas' procedure), 1 operation of HASSAB (after splenectomy), 6 proximal spleno-renal diversion (after splenectomy). After studying the results of the eleven patients, discussion with other surgical procedures, particularly endoscopic procedures is developed. The follow-up of these patients during at least five years is mandatory to give guidelines for post-systemic shunts to prevent rebleeding (near other methods). Treated too late, schistosomiasis has no benefit from drugs (Praziquentel). After a mean period of forty two months, the following results are: mortality: one case (10 days after operation): hepatic insufficiency (group Child B/C). morbidity: one occlusion of the small intestine, after 4 months (debridment), operated at the Provincial hospital of Kratie (case no1). Ten patients resume work, family and social life between Kratie and Sambor in 2002. No rebleeding. No encephalopathy.

[Assessment of mother-to-child HBV transmission at the prenatal consultation in Vientiane, Laos]. / Évaluation du risque de transmission materno-fœtale du virus de l'hépatite B en consultation prénatale à Vientiane, Laos.

Chronic infection with hepatitis B virus (HBV) remains highly endemic in Laos, mainly related to mother to child transmission. Despite the introduction of the vaccination against HBV in the Expanded Programme on Immunization in 2001 and the administration of a vaccine birth dose as part of a 3-dose schedule since 2004, infant immunization coverage remains inadequate because most mothers are not aware of the risks. A survey was conducted in early 2013 in Vientiane capital among women who undergo serologic screening for hepatitis B at the prenatal consultation, to assess their knowledge and risk factors of HBV infection. It included the administration of a standardized questionnaire divided into four parts (socio-demographic data, knowledge about hepatitis B, risk factors and immunization status) and a screening test for the HBV surface antigen (HBsAg). A total of 200 pregnant women were recruited consecutively in Mahosot hospital. They were aged 14-39 years (mean 27 ± 4.76 years), civil servants (37%) or housewives (33.5%) with a secondary or higher education level (80%). Most were multiparous (68.5%) and attended antenatal care in the third trimester of pregnancy (61%). Sixteen (8%) tested HBsAg positive. The HBsAg seroprevalence was higher in the 26-30 years age group, among women above the primary school education level and women practicing the profession of shopkeeper or civil servant, but these differences were not significant. Hepatitis B was known by a small majority (53%) but 26% could name the routes of transmission, 28% considered it as a serious illness and 24.5% were aware of the HBV vaccine. No risk factor for blood or sexual exposure to HBVinfection was significantly linked to the HBsAg carriage. In this sample of pregnant women mostly urban, educated and multiparous with access to a central hospital, the high rate of HBV infection and the low level of knowledge about the risk of mother-to-child HBV transmission reveals a major gap in information and advice that should be provided during prenatal visits. A large scale program of health education focused on the prevention of vertical transmission of HBV should be implemented, parallel to the extension of HBV vaccine coverage including a birth dose for the Lao children.