[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.

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.

[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.

[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.

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.

[Bacterial flora in acute exacerbations of chronic obstructive pulmonary disease (COPD) in Kunming, China]. / Flore bactérienne des exacerbations aiguës de bronchopneumopathie chronique obstructive (BPCO) à Kunming, Chine.

OBJECTIVE: Chinese recommendations for the management of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) include antibiotic treatments targeting the most frequently isolated pathogens according to the severity of COPD. The study objective was to check the relevance of these recommendations in Yunnan, a Southern Chinese province. PATIENTS AND METHODS: A descriptive and analytical survey was conducted in the Kunming Medical University hospital among patients over 60 years of age, hospitalized with AECOPD, between March 2007 and June 2008. RESULTS: The 74 included patients were predominantly male (90%), with a mean age of 78.6 years, active or ex-smokers (81%), mainly with moderate (43%) or severe COPD (34%). Out of 87 AECOPD episodes, 47 (54%) yielded significant quantitative sputum cultures for S. pneumoniae (10%), P. aeruginosa (10%), H. influenzae (7%), M. catarrhalis (7%), and K. pneumoniae (7%). The positivity of sputum cultures was significantly linked with a history of smoking (P=0.002). More than half of the P. aeruginosa isolates were multidrug resistant. CONCLUSIONS: The distribution of pathogens isolated from EABPCO in Kunming corroborates published results. It does not question Chinese recommendations for first-line antibiotic therapy, but the high prevalence of P. aeruginosa and Enterobacteriaceae requires a periodic screening for acquired antibiotic resistance.