Genomic epidemiology of SARS-CoV-2 in Cambodia, January 2020 to February 2021

The first case of coronavirus disease 2019 (COVID-19) in Cambodia was confirmed on 27 January 2020 in a traveller from Wuhan. Cambodia subsequently implemented strict travel restrictions, and although intermittent cases were reported during the first year of the COVID-19 pandemic, no apparent widespread community transmission was detected. Investigating the routes of severe acute respiratory coronavirus 2 (SARS-CoV-2) introduction into the country was critical for evaluating the implementation of public health interventions and assessing the effectiveness of social control measures. Genomic sequencing technologies have enabled rapid detection and monitoring of emerging variants of SARS-CoV-2. Here, we detected 478 confirmed COVID-19 cases in Cambodia between 27 January 2020 and 14 February 2021, 81.3 per cent in imported cases. Among them, fifty-four SARS-CoV-2 genomes were sequenced and analysed along with representative global lineages. Despite the low number of confirmed cases, we found a high diversity of Cambodian viruses that belonged to at least seventeen distinct PANGO lineages. Phylogenetic inference of SARS-CoV-2 revealed that the genetic diversity of Cambodian viruses resulted from multiple independent introductions from diverse regions, predominantly, Eastern Asia, Europe, and Southeast Asia. Most cases were quickly isolated, limiting community spread, although there was an A.23.1 variant cluster in Phnom Penh in November 2020 that resulted in a small-scale local transmission. The overall low incidence of COVID-19 infections suggests that Cambodia's early containment strategies, including travel restrictions, aggressive testing and strict quarantine measures, were effective in preventing large community outbreaks of COVID-19.

The Pandemic Experience in Southeast Asia: Interface Between SARS-CoV-2, Malaria, and Dengue

Southeast Asia (SEA) emerged relatively unscathed from the first year of the global SARS-CoV-2 pandemic, but as of July 2021 the region is experiencing a surge in case numbers primarily driven by Alpha (B.1.1.7) and subsequently the more transmissible Delta (B.1.617.2) variants. While initial disease burden was mitigated by swift government responses, favorable cultural and societal factors, the more recent rise in cases suggests an under-appreciation of prior prevalence and over-appreciation of possible cross-protective immunity from exposure to endemic viruses, and highlights the effects of vaccine rollout at varying tempos and of variable efficacy. This burgeoning crisis is further complicated by co-existence of malaria and dengue in the region, with implications of serological cross-reactivity on interpretation of SARS-CoV-2 assays and competing resource demands impacting efforts to contain both endemic and pandemic disease.

Human Infection with Avian Influenza A(H9N2) Virus, Cambodia, February 2021

In February 2021, routine sentinel surveillance for influenza-like illness in Cambodia detected a human avian influenza A(H9N2) virus infection. Investigations identified no recent H9N2 virus infections in 43 close contacts. One chicken sample from the infected child’s house was positive for H9N2 virus and genetically similar to the human virus.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Rapid metagenomic characterization of a case of imported COVID-19 in Cambodia

Rapid production and publication of pathogen genome sequences during emerging disease outbreaks provide crucial public health information. In resource-limited settings, especially near an outbreak epicenter, conventional deep sequencing or bioinformatics are often challenging. Here we successfully used metagenomic next generation sequencing on an iSeq100 Illumina platform paired with an open-source bioinformatics pipeline to quickly characterize Cambodia's first case of COVID-2019.

Cholera in selected countries in Asia

INTRODUCTION

Although the current pandemic of cholera originated in Asia, reports of cholera cases and outbreaks in the region are sparse. To provide a sub-regional assessment of cholera in South and Southeast Asia, we collated published and unpublished data from existing surveillance systems from Bangladesh, Cambodia, India, Malaysia, Nepal, Pakistan, Philippines, Thailand and Vietnam.

METHODS

Data from existing country surveillance systems on diarrhea, acute watery diarrhea, suspected cholera and/or confirmed cholera in nine selected Asian countries (Bangladesh, Cambodia, India, Malaysia, Nepal, Pakistan, Philippines, Thailand and Vietnam) from 2011 to 2015 (or 2016, when available) were collated. We reviewed annual cholera reports from WHO and searched PubMed and/or ProMED to complement data, where information is not completely available.

RESULTS

From 2011 to 2016, confirmed cholera cases were identified in at least one year of the 5- or 6-year period in the countries included. Surveillance for cholera exists in most countries, but cases are not always reported. India reported the most number of confirmed cases with a mean of 5964 cases annually. The mean number of cases per year in the Philippines, Pakistan, Bangladesh, Malaysia, Nepal and Thailand were 760, 592, 285, 264, 148 and 88, respectively. Cambodia and Vietnam reported 51 and 3 confirmed cholera cases in 2011, with no subsequent reported cases.

DISCUSSION AND CONCLUSION

We present consolidated results of available surveillance in nine Asian countries and supplemented these with publication searches. There is paucity of readily accessible data on cholera in these countries. We highlight the continuing existence of the disease even in areas with improved sanitation and access to safe drinking water. Continued vigilance and improved surveillance in countries should be strongly encouraged.

Circulation and characterization of seasonal influenza viruses in Cambodia, 2012-2015

Background

Influenza virus circulation is monitored through the Cambodian influenza‐like illness (ILI) sentinel surveillance system and isolates are characterized by the National Influenza Centre (NIC). Seasonal influenza circulation has previously been characterized by year‐round activity and a peak during the rainy season (June‐November).

Objectives

We documented the circulation of seasonal influenza in Cambodia for 2012‐2015 and investigated genetic, antigenic, and antiviral resistance characteristics of influenza isolates.

Patients/Methods

Respiratory samples were collected from patients presenting with influenza‐like illness (ILI) at 11 hospitals throughout Cambodia. First‐line screening was conducted by the National Institute of Public Health and the Armed Forces Research Institute of Medical Sciences. Confirmation of testing and genetic, antigenic and antiviral resistance characterization was conducted by Institute Pasteur in Cambodia, the NIC. Additional virus characterization was conducted by the WHO Collaborating Centre for Reference and Research on Influenza (Melbourne, Australia).

Results

Between 2012 and 2015, 1,238 influenza‐positive samples were submitted to the NIC. Influenza A(H3N2) (55.3%) was the dominant subtype, followed by influenza B (30.9%; predominantly B/Yamagata‐lineage) and A(H1N1)pdm09 (13.9%). Circulation of influenza viruses began earlier in 2014 and 2015 than previously described, coincident with the emergence of A(H3N2) clades 3C.2a and 3C.3a, respectively. There was high diversity in the antigenicity of A(H3N2) viruses, and to a smaller extent influenza B viruses, during this period, with some mismatches with the northern and southern hemisphere vaccine formulations. All isolates tested were susceptible to the influenza antiviral drugs oseltamivir and zanamivir.

Conclusions

Seasonal and year‐round co‐circulation of multiple influenza types/subtypes were detected in Cambodia during 2012‐2015.

Cholera prevention and control in Asian countries

Cholera remains a major public health problem in many countries. Poor sanitation and inappropriate clean water supply, insufficient health literacy and community mobilization, absence of national plans and cross-border collaborations are major factors impeding optimal control of cholera in endemic countries.

In March 2017, a group of experts from 10 Asian cholera-prone countries that belong to the Initiative against Diarrheal and Enteric Diseases in Africa and Asia (IDEA), together with representatives from the World Health Organization, the US National Institutes of Health, International Vaccine Institute, Agence de médecine préventive, NGOs (Save the Children) and UNICEF, met in Hanoi (Vietnam) to share progress in terms of prevention and control interventions on water, sanitation and hygiene (WASH), surveillance and oral cholera vaccine use.

This paper reports on the country situation, gaps identified in terms of cholera prevention and control and strategic interventions to bridge these gaps.

Analytical and field evaluation of the Biocentric Generic HCV assay on open polyvalent PCR platforms in France and Cambodia

BACKGROUND

Implementation of affordable methods for HCV viremia is a key priority for identifying individuals who need treatment among persons screened positive for HCV antibodies. Different HCV PCR assays for use on open polyvalent PCR platforms are currently commercially available but studies evaluating the performances of these nucleic acid tests are needed.

OBJECTIVES

In the present study, we evaluated the analytical and clinical performances of a recently developed HCV RNA PCR assay for detection and quantification of HCV viremia.

STUDY DESIGN

In this study the Biocentric Generic HCV PCR was compared to the Roche Cobas AmpliPrep/Cobas TaqMan HCV RNA assay. Analytical and clinical performances was evaluated on reference materials and HCV plasma samples collected in 141 patients attending at the Montpellier University Hospital in France. Field evaluation was performed on samples collected in 185 patients attending at Medical Laboratory, Institut Pasteur in Cambodia.

RESULTS

The lower limit of detection ranged from 50 HCV RNA IU/ml to 300 HCV RNA IU/ml using four different Diasorin and Qiagen automated or manual extraction methods. The specificity (CI) and sensitivity of the assay were 100% (92.5-100), and 98.7% (92.3-99.9), respectively, in France, and 100% (95.5-100), and 100% (94.4-100%), respectively, in Cambodia. Bland-Altman analysis shown good agreement between the two assays including for genotypes 6 HCV, which represent the majority of HCV isolates in Cambodia.

CONCLUSIONS

The Biocentric Generic HCV assay has shown overall satisfactory analytical performances and a close agreement to the Cobas HCV assay on clinical specimens collected in France and Cambodia. There is an urgent need to further evaluate commercial assays dedicated to HCV detection and quantification using open polyvalent PCR platforms in different settings.

Using a hospital admission survey to estimate the burden of influenza-associated severe acute respiratory infection in one province of Cambodia-methods used and lessons learned

Background

Understanding the burden of influenza‐associated severe acute respiratory infection (SARI) is important for setting national influenza surveillance and vaccine priorities. Estimating influenza‐associated SARI rates requires hospital‐based surveillance data and a population‐based denominator, which can be challenging to determine.

Objectives

We present an application of the World Health Organization's recently developed manual (WHO Manual) including hospital admission survey (HAS) methods for estimating the burden of influenza‐associated SARI, with lessons learned to help others calculate similar estimates.

Methods

Using an existing SARI surveillance platform in Cambodia, we counted influenza‐associated SARI cases during 2015 at one sentinel surveillance site in Svay Rieng Province. We applied WHO Manual‐derived methods to count respiratory hospitalizations at all hospitals within the catchment area, where 95% of the sentinel site case‐patients resided. We used HAS methods to adjust the district‐level population denominator for the sentinel site and calculated the incidence rate of influenza‐associated SARI by dividing the number of influenza‐positive SARI infections by the adjusted population denominator and multiplying by 100 000. We extrapolated the rate to the provincial population to derive a case count for 2015. We evaluated data sources, detailed steps of implementation, and identified lessons learned.

Results

We estimated an adjusted influenza‐associated 2015 SARI rate of 13.5/100 000 persons for the catchment area of Svay Rieng Hospital and 77 influenza‐associated SARI cases in Svay Rieng Province after extrapolation.

Conclusions

Methods detailed in the WHO Manual and operationalized successfully in Cambodia can be used in other settings to estimate rates of influenza‐associated SARI.

153 Fertilisation of Cattle Oocytes is Linked to Novel Waves of a Ca2+ Fluorophore in Cumulus Cells

During fertilization, multiple intracellular calcium (Ca2+) oscillations are initiated after sperm binding to the oocyte vitelline membrane. This Ca2+ signalling has been extensively studied in denuded mouse and Xenopus oocytes but minimally studied in larger mammals. Cows in particular are unusual, as the few studies on oocyte activation have observed fewer Ca2+ oscillations during fertilisation compared with mice. Furthermore, cattle intracytoplasmic sperm injection (ICSI) is inefficient, despite parthenogenetic activation occurring readily. We hypothesise that cumulus cells are important for cattle oocyte activation at fertilisation. Here, we assessed the behaviour of Ca2+oscillations in fertilising intact cattle cumulus–oocyte complexes (COC). Abattoir-derived cattle COC were matured and fertilised in vitro using Bovine Vitro Media Suite (IVF Vet Solutions). The COC were stained 3.5 h after insemination with the Ca2+ fluorescent probe Fluo4AM (5 μM, Molecular Probes Inc., Eugene, OR, USA) for 30 min, washed, and imaged every 5 min for 6 h in a Fluoview FV10i incubating time-lapse confocal microscope (Olympus) before being returned to culture. Embryo development was assessed at Day 8 to confirm fertilisation. Fluo4AM fluorescence intensity was assessed using FIJI ImageJ. Mean relative intensity over time was graphed for specific regions of interest and the area under graphs was calculated to quantify differences for comparison using a Mann-Whitney Test (mean ± SEM). Experiment 1 (4 reps of 10 COC) compared confirmed fertilised v. uninseminated; experiment 2 (2 reps of 10 COC) compared inseminated COC ± 10 μM BAPTA-AM (Ca2+ chelator, Sigma-Aldrich, St. Louis, MO, USA). There were distinct coordinated waves of differing Fluo4AM intensity in both the oocyte and the cumulus cells surrounding the confirmed fertilised oocytes. This contrasted to the random uncoordinated flashes of Fluo4AM fluorescence in the cumulus cells of the uninseminated oocytes. The fluorescence pattern in +BAPTA-AM COC matched the random flashes observed in the uninseminated group of experiment 1. The fluorescence in the media surrounding the COC immediately following the Fluo4AM waves spiked and then plateaued at a higher level of fluorescence. This was quantified by assessing the area under the graph for 1 h of the plateau following the fluorescence spike. There were no differences between confirmed fertilised (346.4 ± 41.62) and uninseminated groups (239.8 ± 32.08; P > 0.05), but this was affected by differences in cumulus dispersal due to the presence or absence of sperm. Experiment 2 used BAPTA-AM to block oocyte activation with sperm present in both groups and showed a significant difference between the fluorescence increase in the media of the 2 groups (–BAPTA-AM: 311.2 ± 31.57, +BAPTA-AM: 201.4 ± 26.59; P < 0.03). Although the physiological significance has yet to be determined, we have observed a novel Ca2+ wave in the cumulus cells that could be linked to oocyte activation in cattle. There was a significant increase in Fluo4AM fluorescence in the media surrounding the COC, which may indicate cumulus cells are releasing Ca2+ at the time of oocyte activation.

Establishing seasonal and alert influenza thresholds in Cambodia using the WHO method: implications for effective utilization of influenza surveillance in the tropics and subtropics

OBJECTIVE

To establish seasonal and alert thresholds and transmission intensity categories for influenza to provide timely triggers for preventive measures or upscaling control measures in Cambodia.

METHODS

Using Cambodia's influenza-like illness (ILI) and laboratory-confirmed influenza surveillance data from 2009 to 2015, three parameters were assessed to monitor influenza activity: the proportion of ILI patients among all outpatients, proportion of ILI samples positive for influenza and the product of the two. With these parameters, four threshold levels (seasonal, moderate, high and alert) were established and transmission intensity was categorized based on a World Health Organization alignment method. Parameters were compared against their respective thresholds.

RESULTS

Distinct seasonality was observed using the two parameters that incorporated laboratory data. Thresholds established using the composite parameter, combining syndromic and laboratory data, had the least number of false alarms in declaring season onset and were most useful in monitoring intensity. Unlike in temperate regions, the syndromic parameter was less useful in monitoring influenza activity or for setting thresholds.

CONCLUSION

Influenza thresholds based on appropriate parameters have the potential to provide timely triggers for public health measures in a tropical country where monitoring and assessing influenza activity has been challenging. Based on these findings, the Ministry of Health plans to raise general awareness regarding influenza among the medical community and the general public. Our findings have important implications for countries in the tropics/subtropics and in resource-limited settings, and categorized transmission intensity can be used to assess severity of potential pandemic influenza as well as seasonal influenza.

Crowned spiropyran fluoroionophores with a carboxyl moiety for the selective detection of lithium ions

The absorbance and fluorescence spectra of carboxylated spiropyrans containing methyl-1-aza-12-crown-4, methyl-1-aza-15-crown-5, methyl-1-aza-18-crown-6 moieties are compared in the presence of alkali metal ions.

Real-Time Polymerase Chain Reaction Detection of Angiostrongylus cantonensis DNA in Cerebrospinal Fluid from Patients with Eosinophilic Meningitis

Angiostrongylus cantonensis is the most common infectious cause of eosinophilic meningitis. Timely diagnosis of these infections is difficult, partly because reliable laboratory diagnostic methods are unavailable. The aim of this study was to evaluate the usefulness of a real-time polymerase chain reaction (PCR) assay for the detection of A. cantonensis DNA in human cerebrospinal fluid (CSF) specimens. A total of 49 CSF specimens from 33 patients with eosinophilic meningitis were included: A. cantonensis DNA was detected in 32 CSF specimens, from 22 patients. Four patients had intermittently positive and negative real-time PCR results on subsequent samples, indicating that the level of A. cantonensis DNA present in CSF may fluctuate during the course of the illness. Immunodiagnosis and/or supplemental PCR testing supported the real-time PCR findings for 30 patients. On the basis of these observations, this real-time PCR assay can be useful to detect A. cantonensis in the CSF from patients with eosinophilic meningitis.

Epidemiological and virological characteristics of influenza viruses circulating in Cambodia from 2009 to 2011

BACKGROUND

The Cambodian National Influenza Center (NIC) monitored and characterized circulating influenza strains from 2009 to 2011.

METHODOLOGY/PRINCIPAL FINDINGS

Sentinel and study sites collected nasopharyngeal specimens for diagnostic detection, virus isolation, antigenic characterization, sequencing and antiviral susceptibility analysis from patients who fulfilled case definitions for influenza-like illness, acute lower respiratory infections and event-based surveillance. Each year in Cambodia, influenza viruses were detected mainly from June to November, during the rainy season. Antigenic analysis show that A/H1N1pdm09 isolates belonged to the A/California/7/2009-like group. Circulating A/H3N2 strains were A/Brisbane/10/2007-like in 2009 before drifting to A/Perth/16/2009-like in 2010 and 2011. The Cambodian influenza B isolates from 2009 to 2011 all belonged to the B/Victoria lineage represented by the vaccine strains B/Brisbane/60/2008 and B/Malaysia/2506/2004. Sequences of the M2 gene obtained from representative 2009-2011 A/H3N2 and A/H1N1pdm09 strains all contained the S31N mutation associated with adamantanes resistance except for one A/H1N1pdm09 strain isolated in 2011 that lacked this mutation. No reduction in the susceptibility to neuraminidase inhibitors was observed among the influenza viruses circulating from 2009 to 2011. Phylogenetic analysis revealed that A/H3N2 strains clustered each year to a distinct group while most A/H1N1pdm09 isolates belonged to the S203T clade.

CONCLUSIONS/SIGNIFICANCE

In Cambodia, from 2009 to 2011, influenza activity occurred throughout the year with peak seasonality during the rainy season from June to November. Seasonal influenza epidemics were due to multiple genetically distinct viruses, even though all of the isolates were antigenically similar to the reference vaccine strains. The drug susceptibility profile of Cambodian influenza strains revealed that neuraminidase inhibitors would be the drug of choice for influenza treatment and chemoprophylaxis in Cambodia, as adamantanes are no longer expected to be effective.

Formation of Organic Molecular Nanocrystals under Rigid Confinement with Analysis by Solid State NMR

Crystallization in rigid confinement is a promising method to obtain organic molecular nanocrystals. However, the crystallization behavior and the related characterization methods are not well studied. Here we present a systematic study of the nucleation of organic molecular nanocrystals in rigid pores. Four different compounds were studied, ibuprofen, fenofibrate, griseofulvin, and indomethacin, which range from simple to complex molecules. Solid-state Nuclear Magnetic Resonance (NMR) was employed to analyse the structure of these compounds inside pores which are difficult to characterize by other analytical methods. We successfully demonstrated the production of nano-crystalline ibuprofen, fenofibrate and griseofulvin in porous silica particles with ~ 40 nm pores. These nanocrystals showed significant enhancement in dissolution rates. These results help advance the fundamental understanding of nucleation under rigid confinement and may lead to potential applications in developing new formulations in the pharmaceutical industry.

Disability from Japanese encephalitis in Cambodia and Viet Nam

A cohort of Japanese encephalitis (JE) survivors in Cambodia and Viet Nam were assessed at least 4 months after hospital discharge in order to understand the extent of disability after JE. We used a simple assessment tool which focuses on the impact on daily life. In total, 64 disability assessments were conducted: 38 in Cambodia and 26 in Viet Nam. In Cambodia, 4 (11%) children had severe sequelae, suggesting the children would likely be dependent, 15 (39%) had moderate sequelae and 17 (45%) had mild sequelae. In Viet Nam, two (8%) persons had severe sequelae, five (19%) had moderate sequelae and eight (31%) had mild sequelae. In many JE-endemic areas there are no multi-disciplinary teams with sophisticated equipment to assess patients after JE disease. This assessment tool can assist with patient management and generate data to support the need for programmes to prevent disease and improve outcomes for survivors.

A cost-effectiveness analysis of Japanese encephalitis vaccine in Cambodia

This study aimed to evaluate the cost and effectiveness of introducing a live, attenuated vaccine (SA 14-14-2) against Japanese encephalitis (JE) into the immunization program. The study demonstrated that SA 14-14-2 immunization is cost-effective in controlling JE in Cambodia compared to no vaccination. Averting one disability-adjusted life year, from a societal perspective, through the introduction of SA 14-14-2 through routine immunization, or a combination of routine immunization plus a campaign targeting children 1-5 or 1-10 years of age, costs US$22, US$34 and US$53, respectively. Sensitivity analyses confirmed that there was a high probability of SA 14-14-2 immunization being cost-effective under conditions of uncertainty.

156. IDENTIFICATION OF SCAFFOLDING PROTEINS AS PC6 SUBSTRATES IN THE HUMAN ENDOMETRIAL EPITHELIAL CELLS FOR EMBRYO IMPLANTATION

Successful embryo implantation is an important step in establishing pregnancy, which requires a healthy embryo and a receptive endometrium. Establishment of endometrial receptivity involves morphological and physiological changes initially in the endometrial epithelium, however the underlying molecular mechanisms are not fully understood. We have previously demonstrated that proprotein convertase 5/6 (PC6), a member of the proprotein convertase (PC) family, is up-regulated in the endometrium specifically at implantation in association with epithelial differentiation in the human and monkey. PCs convert a range of precursor proteins of important functions into their bioactive forms, they are thus regarded as critical ‘master switch’ molecules. The aim of this study was to identify target proteins of PC6 in the endometrial epithelial cells important for implantation. We used a HEC1A cell line in which PC6 was stably knocked down by siRNA approach (HEC1A-PC6). HEC1A cells that were similarly transfected with a scrambled siRNA sequence (HEC1A-control) were used as the control. Previous study confirmed that HEC1A-PC6 cells had much reduced capacity to adhere to blastocyst. A proteomic comparison between HEC1A-PC6 treated with or without human recombinant PC6 identified ezrin as a potential PC6 substrate. Ezrin is a cytoplasmic protein which is known to bind to ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) thereby translocating to the plasma membrane.This complex has been associated with cytoskeletal re-organisation and changes in cell polarity. Co-immunoprecipitation of ezrin and EBP50 showed that knockdown of PC6 allowed the binding of ezrin to the C-terminus of EBP50 in HEC1A-PC6, whereas PC6 cleavage of EBP50 in HEC1A-control prevented the binding. This was also confirmed by immunofluorescence showing that ezrin and EBP50 were co-localized to the plasma membrane in HEC1A-PC6. This study thus identified that PC6 regulates scaffolding proteins such as EBP50 and ezrin in the endometrium for embryo implantation.

A description of influenza-like illness (ILI) sentinel surveillance in Cambodia, 2006-2008

Influenza-Like Illness (ILI) sentinel surveillance was initiated by the Communicable Disease Control Department (CDC), Ministry of Health, Cambodia and its partners to evaluate the epidemiology of influenza and identify the circulating strains. The surveillance started in late 2006 in four sentinel sites. The objectives of this study were 1) to document the incidence of LI and confirmed influenza cases reported in the national surveillance system from 2006 to 2008, just after the system and the definition were revised, 2) to identify the strains of influenza virus, 3) to compare the major demographic and clinical characteristics between ILI patients having positive and negative tests for influenza virus. An ILI case was defined as having a fever of at least 38 degrees C (axillary), cough or sore throat. A total of 155,866 ILI cases were reported to the CDC from 4 sentinel sites in Cambodia from August 2006 to December 2008. Specimens were collected in 1.8%. Of these, 9.6% tested positive for influenza. Influenza was observed to occur mainly from August to December, with a clear seasonal peak in October, as shown in the data from 2008. A new case definition beginning in August 2008 resulted in a decrease in weekly RI reported cases (from an average of 1,474 cases to 54 cases) and the proportion of positive tests for influenza increased (5.3% vs 29.3%). Influenza and ILI are seasonal in Cambodia. A higher body temperature was used to define ILI, which improved the influenza positivity rates.

166. EMBRYO IMPLANTATION IS ASSOCIATED WITH SPECIFIC EXPRESSION OF PROPROTEIN CONVERTASE 6 IN THE RABBIT UTERUS

Proprotein convertase 5/6 (PC6) is a member of the proprotein convertase family that endoproteolytically cleave latent precursor proteins into their biologically active state. We have previously demonstrated that endometrial PC6 is critical for embryo implantation in mice and primates, including human. PC6 regulates the endometrial physiology specifically at implantation in association with epithelial differentiation during the establishment of endometrial receptivity (in human and monkey) and stromal cell decidualization (in the mouse, human and monkey). PC6 was further confirmed to be a unique PC member that is tightly regulated in the endometrium in relation to implantation. Our further studies (unpublished) suggest that PC6 regulates adhesion molecules in the endometrial epithelium for implantation in women. It is known that between the mouse and human, the endometrial stroma-mediated responses are similar whereas the epithelial cells behave differently. Because PC6 regulates primarily the stromal component (decidualization) in the mouse, in vivo mouse models are critical to investigate the roles of PC6 in decidualization. To address the function of PC6 in endometrial epithelium, non-mouse models relevant to human implantation are required. The rabbit is regarded as an excellent model to study the molecular events of embryo adhesion and attachment. The current study aimed to determine the expression pattern and localisation of PC6 in the rabbit uterus during early pregnancy. Quantitative RT-PCR analysis showed that PC6 mRNA expression was dynamically up-regulated in the rabbit uterus immediately prior to implantation. Western blotting and immunohistochemical analyses demonstrated that PC6 protein was predominantly localised to the basal glands throughout pregnancy, and up-regulated specifically in the epithelium at the embryo attachment site. These findings suggest that PC6 may play an essential role in rabbit implantation, and that the rabbit is a useful animal model to investigate the function of PC6 during embryo attachment.

Influenza activity in Cambodia during 2006-2008

BACKGROUND

There is little information about influenza disease among the Cambodian population. To better understand the dynamics of influenza in Cambodia, the Cambodian National Influenza Center (NIC) was established in August 2006. To continuously monitor influenza activity, a hospital based sentinel surveillance system for ILI (influenza like illness) with a weekly reporting and sampling scheme was established in five sites in 2006. In addition, hospital based surveillance of acute lower respiratory infection (ALRI) cases was established in 2 sites.

METHODS

The sentinel sites collect weekly epidemiological data on ILI patients fulfilling the case definition, and take naso-pharyngeal specimens from a defined number of cases per week. The samples are tested in the Virology Unit at the Institut Pasteur in Phnom Penh. From each sample viral RNA was extracted and amplified by a multiplex RT-PCR detecting simultaneously influenza A and influenza B virus. Influenza A viruses were then subtyped and analyzed by hemagglutination inhibition assay. Samples collected by the ALRI system were tested with the same approach.

RESULTS

From 2006 to 2008, influenza circulation was observed mainly from June to December, with a clear seasonal peak in October shown in the data from 2008.

CONCLUSION

Influenza activity in Cambodia occurred during the rainy season, from June to December, and ended before the cool season (extending usually from December to February). Although Cambodia is a tropical country geographically located in the northern hemisphere, influenza activity has a southern hemisphere transmission pattern. Together with the antigenic analysis of the circulating strains, it is now possible to give better influenza vaccination recommendation for Cambodia.

529. PROPROTEIN CONVERTASE 6 PLAYS A CRITICAL ROLE IN MODULATING THE HUMAN ENDOMETRIAL EPITHELIUM FOR RECEPTIVITY AND IMPLANTATION

Successful embryo implantation is an important step in establishing pregnancy, requiring a healthy embryo and a receptive endometrium. Establishment of endometrial receptivity involves morphological and physiological changes initially in the endometrial epithelium, but the underlying molecular mechanisms are not fully understood. We have previously demonstrated that proprotein convertase 5/6 (PC6), a member of the proprotein convertase (PC) family, is up-regulated in the endometrium specifically at implantation in association with epithelial differentiation, in the human and monkey. PCs convert a range of precursor proteins of important functions into their bioactive forms; they are thus regarded as critical “master switch” molecules. The present study aimed to determine whether PC6 is a critical regulator in the endometrial epithelium for receptivity and implantation. We examined whether endometrial epithelial PC6 dys-regulation is associated with implantation failure in women and whether knockdown of PC6 by siRNA in human endometrial epithelial cells affects embryo adhesion in a cell culture model. Endometrial PC6 expression was assessed by immunohistochemistry in the mid-secretory phase of the menstrual cycle (receptive phase) in two unique clinical cohorts comprising women of known fertility and infertility (with no obvious gynecological disorders, and with fertile males). Endometrial epithelial PC6 levels were significantly lower in infertile vs fertile women in both cohorts. To further establish that PC6 is important for receptivity, a cell model relevant to human implantation was used involving co-culture of uterine epithelial cells with mouse embryos. The epithelial cells were stably transfected with PC6 siRNA and PC6 knock down was confirmed at the levels of mRNA, protein, and activity by real-time RT-PCR, Western blotting and activity assay respectively. Embryos readily adhered to normal epithelial cells, but the adhesion was significantly reduced in the PC6 knockdown epithelial cells. We are currently using proteomics technology to identify the pathways affected by PC6 knockdown. These results strongly suggest that PC6 plays a critical role in modulating the human endometrial epithelium for receptivity and implantation.

175. THE ROLE OF PROPROTEIN CONVERTASE 6 DURING DECIDUALIZATION: REGULATION OF BONE MORPHOGENETIC PROTEIN 2 ACTIVATION

Proprotein convertase 5/6 (PC6), a member of the proprotein convertase (PC) family, is a critical endometrial factor for implantation. PC6 is up-regulated in the endometrium specifically at implantation in association with epithelial differentiation (in human and monkey) and stromal cell decidualization (in the mouse, human and monkey). PC6 is the only PC member that was significantly up-regulated during decidualization. Knockdown of PC6 inhibits decidualization. PCs function by converting a range of important precursor proteins into their bioactive forms. One group of such proteins is the transforming growth factor beta (TGF-beta) superfamily proteins. They are first synthesized as larger biologically inactive precursors, and then are processed by PCs into their active forms. Bone morphogenetic protein 2 (BMP2) is a TGF-beta superfamily member and demonstrated to be essential for decidualization. We hypothesized that BMP2 is one of the proteins that PC6 activates during decidualization. Freshly isolated stromal cells from human endometrium were decidualized in culture with and without inhibition of PC6 activity. The full-length (precursor, non-active) and processed (activated) forms of BMP2 were determined in cellular lysates and media. The precursor form of BMP2 was reduced whereas the active form was increased during decidualization. Inhibition of PC6 activity inhibited decidualization, and this inhibition was accompanied by a total inhibition of the production of active BMP2. To further confirm the role of PC6 in activating BMP2 in decidualization, active BMP2 was added into cells and the decidualization arrest caused by PC6 inhibition was partially rescued. This study demonstrated that PC6 regulates decidualization by activating molecules such as BMP2 that are essential for decidualization.

Etiology of acute lower respiratory tract infection in children at Srinagarind Hospital, Khon Kaen, Thailand

We investigated the etiology of acute lower respiratory infection (ALRI) in children under 5 admitted to Srinagarind Hospital. The causative bacteria and viruses were determined by hemoculture and viral isolation from blood and nasopharyngeal aspirate samples. Antigens of respiratory syncytial virus (RSV) and Chlamydia trachomatis were detected using EIA. The 74 children less than 5 years of age with ALRI enrolled in our study were diagnosed with pneumonia (75.7%), croup (16.2%), and bronchiolitis (8.1%), respectively. Examination of blood or nasopharyngeal aspirate revealed viral or bacterial infections in 26 and 22 cases, respectively, whereas 5 of the children aged under 1 year (10%) were diagnosed with pneumonia caused by Chlamydia trachomatis. RSV was the most common virus detected (24.3%) and was associated with pneumonia and bronchiolitis, while the parainfluenza virus was the primary cause of croup. In cases of pneumonia, bacterial infections were identified in almost all of the cases: and Streptococcus pneumoniae and Haemophilus influenzae were the most commonly isolated (at 8.9% each). Mixed infections were detected in 8 cases (10.8%). The incidence of RSV infection peaked during the especially warm and cool seasons, whereas the bacterial infections were primarily associated with the relatively cool season. Our study indicates that a combined pneumococcal and Hib vaccine and a RSV vaccine would reduce the high rate of pneumonia in children under 5 years of age in Northeast Thailand.

Survey of the prevalence of asthma, allergic rhinitis and eczema in schoolchildren from Khon Kaen, Northeast Thailand. an ISAAC study. International Study of Asthma and Allergies in Childhood

This survey of schoolchildren from Khon Kaen, Northeast Thailand used the standardized ISAAC questionnaires to estimate the prevalence of asthma and other allergic diseases and to compare the results with two previous studies. A total of 6,068 questionnaires were analyzed (2,658, 45.6% males from the 6 to 7 years old group and 3,410, 49.5% male from the 13 to 14 years old group). The three predominant cumulative and 12-month conditions discerned from the written questionnaires among the 6 to 7 vs 13 to 14 years old were: wheezing, at 18.6% and 10.2% vs 20.5% and 11.0%; rhinitis at 38.4% and 33.5% vs 59.4% and 42.5%; and eczema at 18.0% and 15.2% vs 9.9% and 7.4%, respectively. The observed prevalences in our study were similar to those found in Bangkok and slightly higher than those in Chiang Mai, except for 'exercise wheezing' in older children which was two times higher in our study than in the two previous studies. Our study showed seasonal variation of the 'nose' symptoms. The peak prevalence was in the relatively cool and dry season (between November and January), which was the same pattern as Chiang Mai but different from Bangkok (which had a perennial pattern and less climatic variation). Our results concurred with the two previous Thai ISAAC studies. There is a high prevalence of asthma and other allergic diseases among Thai children and there has been a four-fold increase in symptoms since the last decade. If the trend persists asthma and allergic disease may become a pressing health concern of the country.

Behavioural and serological human immunodeficiency virus risk factors among female commercial sex workers in Cambodia

BACKGROUND

The spread of human immunodeficiency virus (HIV) in Cambodia is mainly caused by sexual transmission and the high-risk group in this country are female commercial sex workers (CSW). There are two types of CSW, direct CSW (DCSW) and indirect CSW (IDCSW), who are different from each other in sexual activities. This study was conducted in order to describe the risk factors on HIV for each type of CSW, and to establish effective preventive strategies against the HIV epidemic among CSW.

METHODS

The participants, 143 DCSW and 94 IDCSW, were interviewed using a questionnaire to determine their demographic characteristics and behaviour. Blood samples were taken for serological tests on HIV, Chlamydia trachomatis and syphilis. The association between their behavioural pattern and their serological results was analysed.

RESULTS

The questionnaire study showed that IDCSW had a riskier behavioural pattern than DCSW. The HIV seroprevalence rates of the DCSW and the IDCSW were 52.4% and 22.3%, respectively. Univariate logistic analyses showed a significant association between HIV antibody (HIV-Ab) and current age, age at commencement of commercial sex work, duration of commercial sex work, and the seropositivity of Chlamydia trachomatis-IgG antibody (CT-IgG-Ab) among the DCSW. The analyses also showed a significant relationship between HIV-Ab and CT-IgG-Ab among the IDCSW.

CONCLUSIONS

Improving condom use rate is very important in order to prevent an HIV epidemic among the two types of CSW. This study also suggests it is important to prevent sexually transmitted disease (STD) such as Chlamydia trachomatis infection. The STD control programme could be efficient for HIV prevention, especially among DCSW.

Cross-sectional study on risk factors of HIV among female commercial sex workers in Cambodia

To describe epidemiological features on HIV prevalence among female commercial sex workers (CSWs), a cross-sectional study on sexual behaviour and serological prevalence was carried out in Cambodia. The CSWs were interviewed on their demographic characters and behaviour and their blood samples were taken for testing on sexually transmitted diseases, including HIV, Chlamydia trachomatis, syphilis, and hepatitis B. Associations between risk factors and HIV seropositivity were analysed. High seroprevalence of HIV and Chlamydia trachomatis IgG antibody (CT-IgG-Ab) was shown among the CSWs (54 and 81.7%, respectively). Univariate logistic regression analyses showed an association between HIV seropositivity and age, duration of prostitution, the number of clients per day and CT-IgG-Ab. Especially, high-titre chlamydial seropositivity showed a strong significant association with HIV prevalence. In multiple logistic regression analyses, CT-IgG-Ab with higher titre was significantly independently related to HIV infection. These suggest that existence of Chlamydia trachomatis is highly related to HIV prevalence.