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Background: Pacific Islanders are underrepresented in vaccine efficacy trials. Few studies describe their immune response to COVID-19 vaccination. Yet, this characterization is crucial to re-enforce vaccination strategies adapted to Pacific Islanders singularities., Methods and Findings: We evaluated the humoral immune response of 585 adults, self-declaring as Melanesians, Europeans, Polynesians, or belonging to other communities, to the Pfizer BNT162b2 vaccine. Anti-spike and anti-nucleoprotein IgG levels, and their capacity to neutralize SARS-CoV-2 variants and to mediate antibody-dependent cellular cytotoxicity (ADCC) were assessed across communities at 1 and 3 months post-second dose or 1 and 6 months post-third dose. All sera tested contained anti-spike antibodies and 61.3% contained anti-nucleoprotein antibodies, evidencing mostly a hybrid immunity resulting from vaccination and SARS-CoV-2 infection. At 1-month post-immunization, the 4 ethnic communities exhibited no significant differences in their anti-spike IgG levels (p value = 0.17, in an univariate linear regression model), in their capacity to mediate omicron neutralization (p value = 0.59 and 0.60, in an univariate logistic regression model at 1-month after the second and third dose, respectively) and in their capacity to mediate ADCC (p value = 0.069 in a multivariate linear regression model), regardless of the infection status. Anti-spike IgG levels and functionalities of the hybrid humoral immune response remained equivalent across the 4 ethnic communities during follow-up and at 6 months post-third dose., Conclusions: Our study evidenced Pacific Islander's robust humoral immune response to Pfizer BNT162b2 vaccine, which is pivotal to re-enforce vaccination deployment in a population at risk for severe COVID-19., Trial Registration: This trial has been register in ClinicalTrials.gov (ID: NCT05135585)., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Inizan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background and Aims: Several symptomatic cases of HEV infections were reported to the New Caledonia Island Public Health Service between August and December 2023. This prompted epidemiological and virological investigations to identify the source of infection., Approach and Results: HEV RNA was assessed in symptomatic patients, various food items, and pig farms on the Island. HEV strains were characterized by sequencing. A seroprevalence study was also conducted on asymptomatic blood donors before and after the outbreak. One hundred twenty-seven symptomatic cases were reported. Hospitalization was required for 29/127 patients (22.8%). Hospitalized patients presented more frequently with comorbidities, including liver and cardiovascular diseases (80.7% vs. 27%, p < 0.01), and 3 persons died (2.3%). Among the 100 HEV RNA-positive samples received at the French National Reference Centre for HEV, viral sequencing was possible for 76 samples. All strains were identified as HEV genotype 3, and 74/76 strains were grouped together (nucleotide identity: 98%-100%). Full-length sequencing indicated a new HEV-3 subtype within HEV-3 subclade abk. Only genotype 3f strains were detected on the Island's pig farms. No food items tested positive for HEV RNA. The seroprevalence of HEV IgG and IgM in blood donors was 9.2% (9/98) and 0%, respectively, in 2020, rising to 17.3% (17/98) and 2% (2/98) in 2024., Conclusions: Although all previous large-scale epidemics in Asia and Africa were associated with HEV-1 or 2, the New Caledonia outbreak was linked to HEV-3. A high number of symptomatic cases were admitted to the hospital, with a case-fatality rate of 2.3%., (Copyright © 2024 American Association for the Study of Liver Diseases.)

Objectives: New Caledonia, a former zero-COVID country, was confronted with a SARS-CoV-2 Delta variant outbreak in September 2021. We evaluate the relative contribution of vaccination, lockdown, and timing of interventions on healthcare burden., Methods: We developed an age-stratified mathematical model of SARS-CoV-2 transmission and vaccination calibrated for New Caledonia and evaluated three alternative scenarios., Results: High virus transmission early on was estimated, with R 0 equal to 6.6 (95% confidence interval [6.4-6.7]). Lockdown reduced R 0 by 73% (95% confidence interval [70-76%]). Easing the lockdown increased transmission (39% reduction of the initial R 0 ); but we did not observe an epidemic rebound. This contrasts with the rebound in hospital admissions (+116% total hospital admissions) that would have been expected in the absence of an intensified vaccination campaign (76,220 people or 34% of the eligible population were first-dose vaccinated during 1 month of lockdown). A 15-day earlier lockdown would have led to a significant reduction in the magnitude of the epidemic (-53% total hospital admissions)., Conclusion: The success of the response against the Delta variant epidemic in New Caledonia was due to an effective lockdown that provided additional time for people to vaccinate. Earlier lockdown would have greatly mitigated the magnitude of the epidemic., Competing Interests: The authors have no competing interests to declare., (© 2023 The Authors.)

An increasing number of isolations of Corynebacterium diphtheriae has been observed in recent years in the archipelago of New Caledonia. We aimed to analyze the clinical and microbiological features of samples with C. diphtheriae. All C. diphtheriae isolates identified in New Caledonia from May 2015 to May 2019 were included. For each case, a retrospective consultation of the patient files was conducted. Antimicrobial susceptibility phenotypes, tox gene and diphtheria toxin expression, biovar, and the genomic sequence were determined. Core genome multilocus sequence typing (cgMLST), 7-gene MLST, and search of genes of interest were performed from genomic assemblies. Fifty-eight isolates were included, with a median age of patients of 28 years (range: 9 days to 78 years). Cutaneous origin accounted for 51 of 58 (87.9%) isolates, and C. diphtheriae was associated with Staphylococcus aureus and/or Streptococcus pyogenes in three-quarters of cases. Half of cases came either from the main city Noumea (24%, 14/58) or from the sparsely populated island of Lifou (26%, 15/58). Six tox -positive isolates were identified, associated with recent travel to Vanuatu; 5 of these cases were linked and cgMLST confirmed recent transmission. Two cases of endocarditis in young female patients with a history of rheumatic fever involved tox -negative isolates. The 58 isolates were mostly susceptible to commonly used antibiotics. In particular, no isolate was resistant to the first-line molecules amoxicillin or erythromycin. Resistance to tetracycline was found in a genomic cluster of 17 (29%) isolates, 16 of which carried the tetO gene. There were 13 cgMLST sublineages, most of which were also observed in the neighboring country Australia. Cutaneous infections may harbor nontoxigenic C. diphtheriae isolates, which circulate largely silently in nonspecific wounds. The possible introduction of tox -positive strains from a neighboring island illustrates that diphtheria surveillance should be maintained in New Caledonia, and that immunization in neighboring islands must be improved. Genomic sequencing uncovers how genotypes circulate locally and across neighboring countries. IMPORTANCE The analysis of C. diphtheriae from the tropical archipelago of New Caledonia revealed a high genetic diversity with sublineages that may be linked to Polynesia, Australia, or metropolitan France. Genomic typing allowed confirming or excluding suspected transmission events among cases and contacts. A highly prevalent tetracycline-resistant sublineage harboring the tetO gene was uncovered. Toxigenic isolates were observed from patients returning from Vanuatu, showing the importance of improving vaccination coverage in settings where it is insufficient. This study also illustrates the importance for diphtheria surveillance of the inclusion of isolates from cutaneous sources in addition to respiratory cases, in order to provide a more complete epidemiological picture of the diversity and transmission of C. diphtheriae., Competing Interests: The authors declare no conflict of interest.

The increase in carbapenem-resistant Enterobacterales (CRE) is mostly driven by the spread of carbapenemase-producing (CP) strains. In New Caledonia, the majority of carbapenemases found are IMP-type carbapenemases that are difficult to detect on routine selective media. In this study, a culture-based method with ertapenem selection is proposed to distinguish non-CRE, non-CP-CRE, and CP-CRE from samples with very high bacterial loads. Firstly, assays were carried out with phenotypically well-characterized β-lactam-resistant Enterobacterales isolates. Then, this approach was applied to clinical and environmental samples. Presumptive CP-CRE isolates were finally identified, and the presence of a carbapenemase was assessed. In a collection of 27 phenotypically well-characterized β-lactam-resistant Enterobacterales, an ertapenem concentration of 0.5 µg·mL -1 allowed distinguishing CRE from non-CRE. A concentration of 4 µg·mL -1 allowed distinguishing CP-CRE from non-CP-CRE after nine hours of incubation. These methods allowed isolating 18 CP-CRE from hospital effluents, including the first detection of a KPC in New Caledonia. All these elements show that this cost-effective strategy to distinguish β-lactam-resistant Enterobacterales provides fast and reliable results. This could be applied in the Pacific islands or other resource-limited settings, where limited data are available.

Objectives: Since 2014, Staphylococcus aureus methicillin resistance has been rapidly increasing in New Caledonia and is associated with potential serious clinical repercussions. In the present study, we investigated the epidemiology of methicillin-resistant S. aureus (MRSA) in New Caledonia and the possible emergence of a particular clonal strain., Methods: An overview of the distribution of MRSA in New Caledonia in 2019 is presented. We collected and analysed 171 clinical MRSA isolates from New Caledonia medical laboratories during August and September 2019. Among this collection, 49 representative isolates were analyzed by the French National Reference Center for Staphylococci using the StaphyType DNA microarray, allowing genetic characterization of the isolates., Results: Among the 1144 S. aureus isolated over the year 2019, 442 isolates (39%) were resistant to methicillin, and 62% of these isolates were resistant to fusidic acid (FA). During the inclusion period, FA resistance rate was similar (60%). Genetic characterization evidenced CC6 as the predominant clonal complex (70%) with 26 isolates (53%) identified as CC6-MRSA-[IV+fus] (PVL+)., Conclusions: These findings demonstrated a low diversity of MRSA in New Caledonia, with the dominance of a clonal complex not reported previously. The frequent fusidic acid (FA) resistance in MRSA was associated with a high prevalence of fusC gene, suggesting that FA misuse contributed to driving the selection of this clone. Our findings suggest the recommendation to stop the topical use of FA to control the emergence of this severe MRSA clone and decrease the rate of MRSA in New Caledonia., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Dengue virus infection is endemic in New Caledonia, with outbreaks occurring every year. We evaluated the Biosynex ® Dengue NS1 antigen rapid diagnostic test (RDT) for the early diagnosis of dengue in patients attending a local hospital in northern New Caledonia. Samples collected from patients suspected of dengue infection were tested with RDT at the local laboratory, and then sent to the reference laboratory for confirmation with real-time RT-PCR. A total of 472 samples were included during the study period. RT-PCR yielded a positive result in 154 samples (32.6%). The sensitivity and specificity of the NS1 antigen RDT were 79.9% and 96.2%, respectively. The performance of the RDT varied by the time of sampling and dengue virus serotype. In conclusion, Biosynex ® Dengue NS1 antigen RDT showed a sensitivity and a specificity in the upper range usually reported for this type of test. Several factors can lead to a suboptimal sensitivity, and negative samples with suggestive clinical features should be retested with reference methods.

Objective: Carbapenemase-producing Enterobacteriaceae (CRE) and Enterococcus faecium resistant to vancomycin (VRE) constitute major threats to public health worldwide. The Pacific area is concerned and has implemented strategies to control antimicrobial resistance (AMR). However, accurate epidemiological data are rarely reported. Our study aimed to present the strategies applied to prevent and control the spread of highly resistant bacteria in the Pacific territory of New Caledonia., Patients and Methods: Cohort prospective study of all cases of highly resistant bacteria (HRB) isolated in New Caledonia from September 2004 to December 2020. Evaluation of the impact of the infection control measures implemented in healthcare settings: screening strategy, cohorting unit, IT tools and control of antibiotic prescriptions., Results: A total of 346 patients with HRB were identified. Most of them (63.0%) were infected or colonized by VRE (n=218) and 128 by CRE. While the number of CREs significantly increased from 2013 to 2020 (P<0.0001), control procedures have limited their dissemination. Most patients were colonized by IMP-4-CRE (n=124/128). The incidence density of VRE significantly decreased from 38.52 for 100,000 hospitalisation-days in 2015 to 4.19 for 100,000 hospitalisation-days in 2019 due to systematic screening of patients before sanitary repatriation from Australia and cohorting implementation. The risk of VRE diffusion is now well under control., Conclusions: Our study confirms that it is possible to control the spread of AMR in a circumscribed territory by means of a global control strategy involving screening, cohorting unit, IT tools and antibiotic prescription controls., (Copyright © 2021. Published by Elsevier Masson SAS.)

Leptospirosis is endemic in New Caledonia. Clinical diagnosis is often difficult and its evolution can be fatal. Leptospirosis requires specific management before biological confirmation. Modified Faine criteria (Faine Score) have been suggested to diagnose leptospirosis on epidemiological (parts A and B) and biological (part C) criteria. The main objective of our study was to assess the relevance of the epidemiological-clinical modified Faine score, parts A and B (MF A + B), in patients with suspected leptospirosis in New Caledonia. A monocentric case-control study was conducted in suspect patients for whom a Leptospira polymerase chain reaction (PCR) test was done within the first 7 days of signs onset at the tertiary hospital from January 2018 to January 2019. Cases and control subjects were matched 1:2 in the gender and age categories. Bivariate, and then multivariable, analyses studied the association between the MF A + B score and a positive Leptospira PCR test, adjusted on the variables retained. In all, 35 cases and 70 control subjects matched for age and gender were analyzed. Multivariable analysis by logistic regression found a significant association between an MF A + B score taken from the categories "possible leptospirosis" (score, 20-25) and "presumed leptospirosis" (score, > 26), and the case or control subject status (P < 0.0001). Model performance was high, with an area under the curve value of 99.27%, 93.55% sensitivity, and 96.36% specificity, which classified subjects correctly in 95.35% of cases. Our study suggests using the MF A + B score to identify possible cases of leptospirosis and initiate antibiotic therapy before biological confirmation in New Caledonia. This score should be evaluated in areas where more differential diagnoses exist and where PCR is not widely available.

Compared to the previous 2013-2014 outbreak, dengue 2016-2017 outbreak in New Caledonia was characterized by an increased number of severe forms associated with hepatic presentations. In this study, we assessed the virological factors associated with this enhanced severity. Whole-genome sequences were retrieved from dengue virus (DENV)-1 strains collected in 2013-2014 and from severe and non-severe patients in 2016-2017. Fitness, hepatic tropism and cytopathogenicity of DENV 2016-2017 strains were compared to those of 2013-2014 strains using replication kinetics in the human hepatic cell line HuH7. Whole-genome sequencing identified four amino acid substitutions specific to 2016-2017 strains and absent from 2013-2014 strains. Three of these mutations occurred in predicted T cell epitopes, among which one was also a B cell epitope. Strains retrieved from severe forms did not exhibit specific genetic features. DENV strains from 2016-2017 exhibited a trend towards reduced replicative fitness and cytopathogenicity in vitro compared to strains from 2013-2014. Overall, the 2016-2017 dengue outbreak in New Caledonia was associated with a viral genetic evolution which had limited impact on DENV hepatic tropism and cytopathogenicity. These mutations, however, may have modified DENV strains antigenicity, altering the anti-DENV immune response in some patients, in turn favoring the development of severe forms. Trial registration: ClinicalTrials.gov identifier: NCT04615364.

Background: Hemotropic mycoplasmas, previously classified in the genus Eperythrozoon, have been reported as causing human infections in Brazil, China, Japan, and Spain., Methods: In 2017, we detected DNA from Candidatus Mycoplasma haemohominis in the blood of a Melanesian patient from New Caledonia presenting with febrile splenomegaly, weight loss, life-threatening autoimmune hemolytic anemia, and hemophagocytosis. The full genome of the bacterium was sequenced from a blood isolate. Subsequently, we retrospectively (2011-2017) and prospectively (2018-2019) tested patients who had been hospitalized with a similar clinico-biological picture. In addition, as these patients had been in contact with frugivorous bats (authorized under conditions for hunting and eating in New Caledonia), we investigated the role of these animals and their biting flies by testing them for hemotropic mycoplasmas., Results: There were 15 patients found to be infected by this hemotropic mycoplasma. Among them, 4 (27%) died following splenectomy performed either for spontaneous spleen rupture or to cure refractory autoimmune hemolytic anemia. The bacterium was cultivated from the patient's blood. The full genome of the Neocaledonian Candidatus M. haemohominis strain differed from that of a recently identified Japanese strain. Of 40 tested Pteropus bats, 40% were positive; 100% of collected bat flies Cyclopodia horsfieldi (Nycteribiidae, Diptera) were positive. Human, bat, and dipteran strains were highly similar., Conclusions: The bacterium being widely distributed in bats, Candidatus M. haemohominis, should be regarded as a potential cause of severe infections in humans., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Introduction: Eosinophilic meningitis is a rare form of meningitis with sequelae or death occurring in approximately 2-3% of cases. The most frequent etiological agent is the parasite Angiostrongylus cantonensis. The aim of this study was to characterize New Caledonian cases and to assess the extent to which of A. cantonensis was involved., Material and Methods: We performed a retrospective study of all cases of eosinophilic meningitis (EM) admitted to the Territorial Hospital of New Caledonia, from 2004 to 2019. We performed a descriptive and a multivariate analysis to identify association of variables with severe and fatal cases (or cases with sequelae)., Conclusion: Angiostrongyliasis was confirmed as being responsible for 17 of the 92 reported EM cases in New Caledonia from 2004 to 2019 with most being young adults and non-walking infants, and with two peaks of incidence one during the dry season and one during the rainy season. Considering the high incidence and regularity of cases, the potential reservoirs should be identified to target prevention campaigns., Competing Interests: The authors have declared that no competing interests exist.

Zika virus, an arbovirus responsible for major outbreaks, can cause serious health issues, such as neurological diseases. In the present study, different types of samples (serum, saliva, and urine), collected in 2015-2016 in New Caledonia and French Guiana from 53 patients presenting symptoms and clinical signs triggered by arbovirus infections, were analyzed using a recently developed, and in-house validated, 4-plex RT-qPCR TaqMan method for simultaneous detection and discrimination of the Zika and Chikungunya viruses. Subsequently, statistical analyses were performed in order to potentially establish recommendations regarding the choice of samples type to use for an efficient and early stage Zika infection diagnosis. On this basis, the use of only urine samples presented the highest probability to detect viral RNA from Zika virus. Moreover, such a probability was improved using both urine and saliva samples. Consequently, the added value of non-invasive samples, associated with a higher acceptance level for collection among patients, instead of serum samples, for the detection of Zika infections was illustrated.

Background: In 2017, New Caledonia experienced an outbreak of severe dengue causing high hospital burden (4379 cases, 416 hospital admissions, 15 deaths). We decided to build a local operational model predictive of dengue severity, which was needed to ease the healthcare circuit., Methods: We retrospectively analyzed clinical and biological parameters associated with severe dengue in the cohort of patients hospitalized at the Territorial Hospital between January and July 2017 with confirmed dengue, in order to elaborate a comprehensive patient's score. Patients were compared in univariate and multivariate analyses. Predictive models for severity were built using a descending step-wise method., Results: Out of 383 included patients, 130 (34%) developed severe dengue and 13 (3.4%) died. Major risk factors identified in univariate analysis were: age, comorbidities, presence of at least one alert sign, platelets count < 30 × 10 9 /L, prothrombin time < 60%, AST and/or ALT > 10 N, and previous dengue infection. Severity was not influenced by the infecting dengue serotype nor by previous Zika infection. Two models to predict dengue severity were built according to sex. Best models for females and males had respectively a median Area Under the Curve = 0.80 and 0.88, a sensitivity = 84.5 and 84.5%, a specificity = 78.6 and 95.5%, a positive predictive value = 63.3 and 92.9%, a negative predictive value = 92.8 and 91.3%. Models were secondarily validated on 130 patients hospitalized for dengue in 2018., Conclusion: We built robust and efficient models to calculate a bedside score able to predict dengue severity in our setting. We propose the spreadsheet for dengue severity score calculations to health practitioners facing dengue outbreaks of enhanced severity in order to improve patients' medical management and hospitalization flow.

With over one million cases worldwide annually and a high fatality in symptomatic forms, human leptospirosis is a growing public health concern for the most vulnerable populations, especially in the context of global warming and unplanned urbanization. Although the Asia-Pacific region is particularly affected, accurate epidemiological data are often lacking. We conducted an eleven-year retrospective laboratory-based epidemiological survey of human leptospirosis in New Caledonia. From 2006 to 2016, 904 cases were laboratory-confirmed, including 29 fatalities, corresponding to an average annual incidence of 30.6/100,000 and a case fatality rate of 3.2%. Over the period, there was a major shift from indirect serological diagnosis by MAT to direct diagnosis by real-time PCR, a more specific and sensitive test when performed early in the course of the disease. The systematic implementation of genotyping informed on the variety of the infective strains involved, with a predominance of serogroups Icterohaemorrhagiae and Pyrogenes. The epidemiological pattern showed a marked seasonality with an annual peak in March-April. Interestingly, the seasonal peak in children of school age was significantly earlier and corresponded to school holidays, suggesting that attending school from February on could protect children from environment-borne leptospirosis., Competing Interests: The authors have declared that no competing interests exist.

New Caledonia is a French territory in the South Pacific Ocean. While COVID-19 is expanding over the world, the situation on our island seems controlled with a total of 18 documented cases. We report the measures implemented on our island that probably helped contain the epidemic spread., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Dengue virus (DENV) serotype-2 was detected in the South Pacific region in 2014 for the first time in 15 years. In 2016-2020, DENV-2 re-emerged in French Polynesia, Vanuatu, Wallis and Futuna, and New Caledonia, co-circulating with and later replacing DENV-1. In this context, epidemiological and molecular evolution data are paramount to decipher the diffusion route of this DENV-2 in the South Pacific region. In the current work, the E gene from 23 DENV-2 serum samples collected in Vanuatu, Fiji, Wallis and Futuna, and New Caledonia was sequenced. Both maximum likelihood and Bayesian phylogenetic analyses were performed. While all DENV-2 strains sequenced belong to the Cosmopolitan genotype, phylogenetic analysis suggests at least three different DENV-2 introductions in the South Pacific between 2017 and 2020. Strains retrieved in these Pacific Islands Countries and Territories (PICTs) in 2017-2020 are phylogenetically related, with strong phylogenetic links between strains retrieved from French PICTs. These phylogenetic data substantiate epidemiological data of the DENV-2 diffusion pattern between these countries.

Viruses are suspected to play a role in the multifactorial pathogenesis of sudden infant death. We described a sudden and unexpected death in a 5-month-old boy, with detection of both enterovirus and parechovirus RNA in the blood. This is the first report of a dual viraemia of enterovirus and parechovirus and its potential association with a sudden unexpected infant death. Extensive sampling and testing especially using molecular methods currently available is needed to better understanding the "hypothetical" link between viral infections and sudden infant death., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2020 by the American Academy of Pediatrics.)

Arboviruses are viruses transmitted to humans by the bite of infected mosquito vectors. Over the last decade, arbovirus circulation has increasingly been detected in New Caledonia (NC), a French island territory located in the subtropical Pacific region. Reliable epidemiological, entomological, virological and climate data have been collected in NC over the last decade. Here, we describe these data and how they inform arboviruses' epidemiological profile. We pinpoint areas which remain to be investigated to fully understand the peculiar epidemiological profile of arbovirus circulation in NC. Further, we discuss the advantages of conducting studies on arboviruses dynamics in NC. Overall, we show that conclusions drawn from observations conducted in NC may inform epidemiological risk assessments elsewhere and may be vital to guide surveillance and response, both in New Caledonia and beyond.

Background: Estimates of leptospirosis morbidity identified Oceania as the region with highest burden. Besides Australia and New Zealand, Oceania is home of Pacific Island Countries and Territories, most of which are developing countries facing a number of challenges. Their archipelago geography notably affects health infrastructure and access to healthcare. Although human leptospirosis was formerly identified in Vanuatu, there is a lack of knowledge of this disease in the country. We aimed to identify leptospirosis in outpatients visiting the hospital., Methodology/principal Findings: We conducted a clinical study to investigate leptospirosis as a cause of non-malarial acute febrile illness in Vanuatu. A total 161 outpatients visiting the outpatient clinics at Port Vila Central Hospital for internal medicine were recruited over 20 month. We showed that leptospirosis significantly affects humans in Vanuatu: 12 cases were confirmed by real-time PCR on acute blood samples (n = 5) or by high serology titers evidencing a recent infection (MAT titer ≥800 or ELISA≥18 Units, n = 7). A high rate of positive serology was also evidenced, by MAT (100

Zika virus (ZIKV) infection has been associated with neurologic disorders including Guillain-Barré syndrome (GBS). In New Caledonia during the ZIKV outbreak (2014-2015), case-control and retrospective studies have been performed to assess the link between ZIKV and GBS. Among the 15 cases included, 33% had evidence of a recent ZIKV infection compared to only 3.3% in the 30 controls involved. All patients were Melanesian, had facial diplegia and similar neurophysiological pattern consistent with acute inflammatory demyelinating polyneuropathy, and recovered well. Furthermore, during the peak of ZIKV transmission, we observed a number of GBS cases higher than the calculated upper limit, emphasizing the fact that ZIKV is now a major trigger of GBS.

Summary: We investigated 10 mother-newborn pairs and found a 90% rate of dengue virus (DENV) transmission during the perinatal period. Here, we describe DENV kinetics in the sera of newborns before the onset of disease. Of the breast-milk samples analyzed, 75% tested positive for DENV., Background: Dengue is the most common mosquito-borne viral disease in humans. With this study, we aimed to investigate the risk of vertical (DENV) transmission during the peripartum period and to describe its viral kinetics in serum and breast milk., Methods: We carried out a prospective study during the 2012-2013 dengue epidemic in New Caledonia, its most severe on record. All mothers hospitalized at the Centre Hospitalier Territorial in Nouméa, New Caledonia, with symptoms of dengue infection between 7 days before and 2 days after delivery and/or whose infant was infected during breastfeeding were investigated. DENV was detected and quantified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) in sera and breast milk (mothers), sera and gastric fluid (newborns), cord blood, and placentas. DENV kinetics and sequences in sera and breast milk were studied. Clinical presentation and biological evolution in mother-newborn pairs were analyzed., Results: Ten mother-newborn pairs were investigated over an 11-month period. One premature birth, 3 hemorrhagic complications, and 1 maternal death occurred. Nine newborns were infected and symptomatic. One case of deep thrombocytopenia and 1 case of anoxic encephalopathy occurred. DENV was detected in breast milk samples from 9 (75%) of 12 infected breastfeeding mothers. Original DENV kinetics in sera and breast milk were described., Conclusions: The occurrence of vertical DENV transmission was high (90%) in viremic mothers at delivery, and these mothers and their infants were at major risk for obstetric and neonatal complications. The modes of viral transmission are difficult to clarify. The risk of DENV transmission through breast milk seems plausible. Close follow-up of mothers and prolonged surveillance of their newborns are required for minimizing complications. Complementary studies are needed to elaborate preventive recommendations., (© The Author 2016. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Various forms of neurological manifestations are reported in dengue fever. We describe here three cases of concomitant Guillain-Barré syndrome and dengue virus (DENV) infection during the largest DENV-1 outbreak in New Caledonia. Research of viral RNA was positive in both blood and CSF samples. All patients were treated with intravenous polyvalent immunoglobulins and recovered without sequelae within one week., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Human enteric viruses occur in high concentrations in wastewater and can contaminate receiving environmental waters. Due to the lack of data on the prevalence of enteric viruses in New Caledonia, the presence and the concentrations of enteric viruses in wastewater and seawater were determined. Untreated wastewater and seawater samples were collected monthly for 1 year from a wastewater treatment plant (WWTP) and from the WWTP's outlet, located directly on a popular recreational beach. Samples were tested for norovirus genogroups I and II (NoV GI and GII), astroviruses (AsV), sapoviruses (SaV), enteroviruses (EV), hepatitis A viruses (HAV), rotaviruses (RoV), human adenoviruses (HAdV) and human polyomaviruses (HPyV). To support these data, faecal samples from cases of gastroenteritis were tested for the first time for NoV and detected in the population. NoV GI, NoV GII, EV, SaV, HAdV and HPyV were detected in all wastewaters, RoV in 75% and AsV in 67%. HAV were not detected in wastewater. Overall, 92% of seawater samples were positive for at least one virus. HPyV were detected most frequently in 92% of samples and at concentrations up to 7.7 × 10(3) genome copies/L. NoV GI, NoV GII, EV, SaV, RoV and HAdV were found in 33, 66, 41, 33, 16 and 66% of seawater samples, respectively. AsV were not detected in seawater. This study reports for the first time the presence of NoV and other enteric viruses in New Caledonia and highlights the year-round presence of enteric viruses in the seawater of a popular beach.

We aimed to evaluate parameters for their value as severity markers in hospitalized leptospirosis patients. We recruited 47 informed adult consenting patients and assessed a number of clinical, hematological, biochemical, and biological variables. Patients were sorted according to severity based on fatality or the requirement of mechanical ventilation or dialysis; the parameters studied were compared between groups on inclusion and the next day. Beside septic shock presentation or a high severity score (Simplified Acute Physiology Score; SAPS II), increased lactate, total bilirubin, lipase, and AST/ALT ratio or a decreased cytokines IL-10/TNF-α ratio were all significantly associated with severity. The gene expression of the IL-1 receptor antagonist IL-1ra, IL-1α, and the long pentraxin PTX-3 were also transcribed at higher levels in most severe cases. Patients could rapidly improve or deteriorate, highlighting the need for a new assessment the next day. Our results add to the limited body of knowledge about severity markers in leptospirosis. They also suggest that patients should be reassessed the next day before being possibly discharged from the hospital. Further studies are needed in order to confirm relevant and reliable prognostic parameters in leptospirosis that would be helpful for the purpose of triage.

Purpose: Invasive Meningococcal Disease (IMD) is three fold more common in New Caledonia (NC) than in metropolitan France and many IMD cases (35.7%) are due to Y and W135 serogroups. The purpose of our study was to identify IMD risk factors in NC., Methods: A retrospective study of all IMD cases that occurred in NC between 2005 and 2011 was conducted. Socio-environmental, clinical and biological data were collected. A search for immune deficiency was proposed to all cases. IMD presentation and outcome were compared according to meningoccal serogroups and the complement deficiency status (C-deficiency)., Results: Sixty-six sporadic IMD cases (29 B serogroup, 20 Y or W135, 6 C, 1 A, 10 unknown) occurred in 64 patients often <24 years-old and of Melanesian origin. Five patients died (7.8%). No socio-environmental risk factors were identified. No asplenia, HIV infection or immunoglobulin deficiencies were found. Two patients had diabetes and 28 of 53 (52.8%) patients had C-deficiency including 20 (71.4%) cases of late complement component deficiency. Patients with C-deficiency were mainly Melanesian (92.8%) originating from the Loyalty Islands (62.1%). They were mostly infected with Y/W135 (42.9%) or B serogroups (32.1%). They often developed later and more severe disease than patients without C-deficiency (need for intensive cares in 60% versus 28.0% of cases, p = 0.01)., Conclusions: A high prevalence of C-deficiency in the Melanesian population may explain epidemiological and clinical features of IMD in NC. Our results imply an adaptation of meningococcal vaccine strategies in NC.

We describe the kinetics of Zika virus (ZIKV) detection in serum and urine samples of 6 patients. Urine samples were positive for ZIKV >10 days after onset of disease, which was a notably longer period than for serum samples. This finding supports the conclusion that urine samples are useful for diagnosis of ZIKV infections.

Background: The epidemiology of dengue in the South Pacific has been characterized by transmission of a single dominant serotype for 3-5 years, with subsequent replacement by another serotype. From 2001 to 2008 only DENV-1 was reported in the Pacific. In 2008, DENV-4 emerged and quickly displaced DENV-1 in the Pacific, except in New Caledonia (NC) where DENV-1 and DENV-4 co-circulated in 2008-2009. During 2012-2013, another DENV-1 outbreak occurred in NC, the third DENV-1 outbreak in a decade. Given that dengue is a serotype-specific immunizing infection, the recurrent outbreaks of a single serotype within a 10-year period was unexpected., Findings: This study aimed to inform this phenomenon by examining the phylogenetic characteristics of the DENV-1 viruses in NC and other Pacific islands between 2001 and 2013. As a result, we have demonstrated that NC experienced introductions of viruses from both the Pacific (genotype IV) and South-east Asia (genotype I). Moreover, whereas genotype IV and I were co-circulating at the beginning of 2012, we observed that from the second half of 2012, i.e. during the major DENV-1 outbreak, all analyzed viruses were genotype I suggesting that a genotype switch occurred., Conclusions: Repeated outbreaks of the same dengue serotype, as observed in NC, is uncommon in the Pacific islands. Why the earlier DENV-1 outbreaks did not induce sufficient herd immunity is unclear, and likely multifactorial, but the robust vector control program may have played a role by limiting transmission and thus maintaining a large susceptible pool in the population.

Sexually transmitted infections have been described as one of the major health problems in several countries of the Pacific Region. The objective of the study was to estimate the prevalence of pregnant women infected with HIV and/or syphilis in New Caledonia. HIV and syphilis test results were obtained from women attending antenatal clinics. From 2008 to 2011, 3353 pregnant women were tested with a mean prevalence of active syphilis found at 5.6/100,000. No pregnant women tested positive for HIV. Despite available resources and public health strategies similar to those existing in France, active syphilis prevalence is high in New Caledonia. Surprisingly, HIV seroprevalence remains far below the figures reported in mainland countries. However, social and economic changes as well as the looming referendum on independence scheduled in 2014 may have a potential negative impact on public health resources. The need for action to control syphilis and other curable sexually transmitted infections is pressing in order to prevent further spread of HIV in New Caledonia.

Background: In endemic areas, leptospirosis is more common and more severe in adults compared with children. Reasons to explain this discrepancy remain unclear and limited data focusing on adolescents are available. The objective of the study was to describe disease spectrum and outcome differences in children and adolescents admitted for leptospirosis in a large at-risk population., Methods: Clinical and laboratory data were obtained on hospitalized cases in New Caledonia from 2006 to 2012., Results: Data of 60 patients <18 years of age (25 children under 14 and 35 adolescents aged 14 to 17) with confirmed leptospirosis were analyzed. Compared with children, adolescents presented more often with classic features of Weil disease (p = 0.02), combining hepatic and renal involvement with or without pulmonary participation. Jarisch-Herxheimer reactions were observed more often among adolescents (p<0.01). The overall case fatality rate was low (1 adolescent versus 0 children)., Conclusion: Severe leptospirosis in adolescents may be more likely to show adults' characteristics compared with children. Further studies are required to explore age-dependant host factors, including puberty-related physiological changes.

We report a case of vertical transmission of dengue infection. The virus was detected and quantified by reverse-transcription polymerase chain reaction in sequential blood samples from mother and child as well as in breast milk, but not in cord blood. This case poses questions about the risk of breastfeeding transmission of dengue virus.

Background : Leptospirosis is a growing public health concern in many tropical and subtropical countries. However, its diagnosis is difficult because of non-specific symptoms and concurrent other endemic febrile diseases. In many regions, the laboratory diagnosis is not available due to a lack of preparedness and simple diagnostic assay or difficult access to reference laboratories. Yet, an early antibiotic treatment is decisive to the outcome. The need for Rapid Diagnostic Tests (RDTs) for bedside diagnosis of leptospirosis has been recognized. We developed a vertical flow immunochromatography strip RDT detecting anti- Leptospira human IgM and evaluated it in patients from New Caledonia, France, and French West Indies. Methodology/Principal Findings : Whole killed Leptospira fainei cells were used as antigen for the test line and purified human IgM as the control line. The mobile phase was made of gold particles conjugated with goat anti-human IgM. Standards for Reporting of Diagnostic Accuracy criteria were used to assess the performance of this RDT. The Microscopic Agglutination Test (MAT) was used as the gold standard with a cut-off titer of ≥400. The sensitivity was 89.8% and the specificity 93.7%. Positive and negative Likelihood Ratios of 14.18 and 0.108 respectively, and a Diagnostic Odds Ratio of 130.737 confirmed its usefulness. This RDT had satisfactory reproducibility, repeatability, thermal tolerance and shelf-life. The comparison with MAT evidenced the earliness of the RDT to detect seroconversion. When compared with other RDT, the Vertical Flow RDT developed displayed good diagnostic performances., Conclusions/significance: This RDT might be used as a point of care diagnostic tool in limited resources countries. An evaluation in field conditions and in other epidemiological contexts should be considered to assess its validity over a wider range of serogroups or when facing different endemic pathogens. It might prove useful in endemic contexts or outbreak situations.

Objective: Vaccination is the most effective way to prevent seasonal influenza and its severe outcomes. The objective of our study was to synthesize information on seasonal influenza vaccination policies, recommendations and practices in place in 2011 for all countries and areas in the Western Pacific Region of the World Health Organization (WHO)., Methods: Data were collected via a questionnaire on seasonal influenza vaccination policies, recommendations and practices in place in 2011., Results: Thirty-six of the 37 countries and areas (97%) responded to the survey. Eighteen (50%) reported having established seasonal influenza vaccination policies, an additional seven (19%) reported having recommendations for risk groups for seasonal influenza vaccination only and 11 (30%) reported having no policies or recommendations in place. Of the 25 countries and areas with policies or recommendations, health-care workers and the elderly were most frequently recommended for vaccination; 24 (96%) countries and areas recommended vaccinating these groups, followed by pregnant women (19 [76%]), people with chronic illness (18 [72%]) and children (15 [60%]). Twenty-six (72%) countries and areas reported having seasonal influenza vaccines available through public funding, private market purchase or both. Most of these countries and areas purchased only enough vaccine to cover 25% or less of their populations., Discussion: In light of the new WHO position paper on influenza vaccines published in 2012 and the increasing availability of country-specific data, countries and areas should consider reviewing or developing their seasonal influenza vaccination policies to reduce morbidity and mortality associated with annual epidemics and as part of ongoing efforts for pandemic preparedness.

Despite greater than 99% of influenza A viruses circulating in the Asia-Pacific region being resistant to the adamantane antiviral drugs in 2011, the large majority of influenza A (>97%) and B strains (∼99%) remained susceptible to the neuraminidase inhibitors oseltamivir and zanamivir. However, compared to the first year of the 2009 pandemic, cases of oseltamivir-resistant A(H1N1)pdm09 viruses with the H275Y neuraminidase mutation increased in 2011, primarily due to an outbreak of oseltamivir-resistant viruses that occurred in Newcastle, as reported in Hurt et al. (2011c, 2012a), where the majority of the resistant viruses were from community patients not being treated with oseltamivir. A small number of influenza B viruses with reduced oseltamivir or zanamivir susceptibility were also detected. The increased detection of neuraminidase inhibitor resistant strains circulating in the community and the detection of novel variants with reduced susceptibility are reminders that monitoring of influenza viruses is important to ensure that antiviral treatment guidelines remain appropriate., (Copyright © 2012. Published by Elsevier B.V.)

Background: Leptospirosis is a major public health concern in New Caledonia (NC) and in other tropical countries. Severe manifestations of the disease are estimated to occur in 5-15% of all human infections worldwide and factors associated with these forms are poorly understood. Our objectives were to identify risk factors and predictors of severe forms of leptospirosis in adults., Methods and Findings: We conducted a retrospective case-control study of inpatients with laboratory-confirmed leptospirosis who were admitted to two public hospitals in NC in 2008-2011. Cases were patients with fatal or severe leptospirosis, as determined by clinical criteria. This approach was meant to be pragmatic and to reflect the routine medical management of patients. Controls were defined as patients hospitalized for milder leptospirosis. Risk and prognostic factors were identified by multivariate logistic regression. Among the 176 patients enrolled in the study, 71 had criteria of severity including 10 deaths (Case Fatality Rate = 14.1%). Three risk factors were independently associated with severe leptospirosis: current cigarette smoking (OR = 2.94 [CI 1.45-5.96]); delays >2 days between the onset of symptoms and the initiation of antibiotherapy (OR = 2.78 [CI 1.31-5.91]); and Leptospira interrogans serogroup Icterohaemorrhagiae as the infecting strain (OR = 2.79 [CI 1.26-6.18]). The following post-admission laboratory results correlated with poor prognoses: platelet count ≤50,000/µL (OR = 6.36 [CI 1.79-22.62]), serum creatinine >200 mM (OR = 5.86 [CI 1.61-21.27]), serum lactate >2.5 mM (OR = 5.14 [CI 1.57-16.87]), serum amylase >250 UI/L (OR = 4.66 [CI 1.39-15.69]) and leptospiremia >1000 leptospires/mL (OR = 4.31 [CI 1.17-15.92])., Conclusions: To assess the risk of developing severe leptospirosis, our study illustrates the benefit for clinicians to have: i) the identification of the infective strain, ii) a critical threshold of qPCR-determined leptospiremia and iii) early laboratory results. In New Caledonia, preventative measures should focus on early presumptive antibacterial therapy and on rodent (reservoir of Icterohaemorrhagiae serogroup) control.

Chikungunya virus (CHIKV) is transmitted to humans through the bite of Aedes mosquitoes. During the 2005-2006 epidemic that occurred in the Indian Ocean Islands, a viral strain harboring a substitution of an alanine to valine at position 226 (E1-A226V) of the E1 glycoprotein enhanced the transmissibility of CHIKV by Aedes albopictus. In March 2011, autochthonous transmission of CHIKV was reported in New Caledonia (NC), an island located in the southwest Pacific Ocean. This was the first report of local chikungunya (CHIK) transmission in this region of the world. Phylogenetic analysis based on the complete genome demonstrated that the CHIKV-NC strain isolated from the first autochthonous human case belongs to the Asian lineage. This is consistent with the Indonesian origin of CHIK cases previously imported and detected. Thus the CHIKV-NC does not present a valine substitution at position E1-226. In New Caledonia, the putative vector of CHIKV is Aedes aegypti, since no other potential vector has ever been described. For example, A. albopictus is not found in NC. Vector competence experiments showed that A. aegypti from New Caledonia was able to transmit, as early as 3 days post-infection, two CHIKV strains: CHIKV-NC belonging to the Asian lineage, and CHIKV-RE from Reunion Island harboring the E1-A226V mutation. Thus the extrinsic incubation period of both CHIKV strains in this vector species could be considered to be quite short. These results illustrate the threat of the spread of CHIKV in the South Pacific region. From February to June 2011 (the end of the alert), only 33 cases were detected. Implementation of drastic vector control measures and the occurrence of the cold season probably helped to limit the extent of the outbreak, but other factors may have also been involved and are discussed.

Background: Dengue dynamics are driven by complex interactions between human-hosts, mosquito-vectors and viruses that are influenced by environmental and climatic factors. The objectives of this study were to analyze and model the relationships between climate, Aedes aegypti vectors and dengue outbreaks in Noumea (New Caledonia), and to provide an early warning system., Methodology/principal Findings: Epidemiological and meteorological data were analyzed from 1971 to 2010 in Noumea. Entomological surveillance indices were available from March 2000 to December 2009. During epidemic years, the distribution of dengue cases was highly seasonal. The epidemic peak (March-April) lagged the warmest temperature by 1-2 months and was in phase with maximum precipitations, relative humidity and entomological indices. Significant inter-annual correlations were observed between the risk of outbreak and summertime temperature, precipitations or relative humidity but not ENSO. Climate-based multivariate non-linear models were developed to estimate the yearly risk of dengue outbreak in Noumea. The best explicative meteorological variables were the number of days with maximal temperature exceeding 32°C during January-February-March and the number of days with maximal relative humidity exceeding 95% during January. The best predictive variables were the maximal temperature in December and maximal relative humidity during October-November-December of the previous year. For a probability of dengue outbreak above 65% in leave-one-out cross validation, the explicative model predicted 94% of the epidemic years and 79% of the non epidemic years, and the predictive model 79% and 65%, respectively., Conclusions/significance: The epidemic dynamics of dengue in Noumea were essentially driven by climate during the last forty years. Specific conditions based on maximal temperature and relative humidity thresholds were determinant in outbreaks occurrence. Their persistence was also crucial. An operational model that will enable health authorities to anticipate the outbreak risk was successfully developed. Similar models may be developed to improve dengue management in other countries.