The agents of human febrile illness can vary by region and country suggesting that diagnosis, treatment, and control programs need to be based on a methodical evaluation of area-specific etiologies. From December 2006 to December 2009, 9,997 individuals presenting with acute febrile illness at nine health care clinics in south-central Cambodia were enrolled in a study to elucidate the etiologies. Upon enrollment, respiratory specimens, whole blood, and serum were collected. Testing was performed for viral, bacterial, and parasitic pathogens. Etiologies were identified in 38.0% of patients. Influenza was the most frequent pathogen, followed by dengue, malaria, and bacterial pathogens isolated from blood culture. In addition, 3.5% of enrolled patients were infected with more than one pathogen. Our data provide the first systematic assessment of the etiologies of acute febrile illness in south-central Cambodia. Data from syndromic-based surveillance studies can help guide public health responses in developing nations.

Collection of surveillance data is essential for monitoring and evaluation of public health programs. Integrated collection of household-based health data, now routinely carried out in many countries through demographic health surveys and multiple indicator surveys, provides critical measures of progress in health delivery. In contrast, biomarker surveys typically focus on single or related measures of malaria infection, HIV status, vaccination coverage, or immunity status for vaccine-preventable diseases (VPD). Here we describe an integrated biomarker survey based on use of a multiplex bead assay (MBA) to simultaneously measure antibody responses to multiple parasitic diseases of public health importance as part of a VPD serological survey in Cambodia. A nationally-representative cluster-based survey was used to collect serum samples from women of child-bearing age. Samples were tested by MBA for immunoglobulin G antibodies recognizing recombinant antigens from Plasmodium falciparum and P. vivax, Wuchereria bancrofti, Toxoplasma gondii, Taenia solium, and Strongyloides stercoralis. Serologic IgG antibody results were useful both for generating national prevalence estimates for the parasitic diseases of interest and for confirming the highly focal distributions of some of these infections. Integrated surveys offer an opportunity to systematically assess the status of multiple public health programs and measure progress toward Millennium Development Goals.

BackgroundThe Cambodian National Influenza Center (NIC) monitored and characterized circulating influenza strains from 2009 to 2011.Methodology/Principal FindingsSentinel 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/SignificanceIn 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.

gTo monitor progress toward maternal and neonatal tetanus elimination (MNTE) in Cambodia, we conducted a nationwide serosurvey of tetanus immunity in 2012. Multistage cluster sampling was used to select 2,154 women aged 15 to 39 years. Tetanus toxoid antibodies in serum samples were measured by gold-standard double-antigen enzyme-linked immunosorbent assay (DAE) and a novel multiplex bead assay (MBA). Antibody concentrations of >0.01 IU/ml by DAE or the equivalent for MBA were considered seroprotective. Estimated tetanus seroprotection was 88% (95% confidence interval [CI], 86 to 89%); 64% (95% CI, 61 to 67%) of women had antibody levels of >1.0 IU/ml. Seroprotection was significantly lower (P < 0.001) among women aged 15 to 19 years (63%) and 20 to 24 years (87%) than among those aged >25 years (96%), among nulliparous women than among parous women (71 versus 97%), and among those living in the western region than among those living in other regions (82 versus 89%). The MBA showed high sensitivity (99% [95% CI, 98 to 99%]) and specificity (92% [95% CI, 88 to 95%]) compared with DAE. Findings were compatible with MNTE in Cambodia (>80% protection). Tetanus immunity gaps should be addressed through strengthened routine immunization and targeted vaccination campaigns. Incorporating tetanus testing in national serosurveys using MBAs, which can measure immunity to multiple pathogens simultaneously, may be beneficial for monitoring MNTE.

Summaryobjectives To describe the results from two years of Japanese encephalitis (JE) sentinel surveillance in Cambodia. conclusions JE is an important cause of meningoencephalitis in Cambodian children. As JE is a vaccine-preventable disease, an immunization programme could result in a considerable reduction in morbidity and mortality from JE among children in Cambodia.