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.     

Ureogenesis in a freshwater teleost: an unusual sub-cellular localization of ornithine-urea cycle enzymes in the freshwater air-breathing teleost Heteropneustes fossilis.

Sub-cellular localization of different ornithine-urea cycle enzymes was studied in the liver and kidney of a freshwater air-breathing teleost. Carbamyl phosphate synthetase, ornithine transcarbamylase, and arginase were found to be localized inside the mitochondria, and argininosuccinate synthetase and argininosuccinate lyase were found in the soluble fraction. Mitochondrial localization of arginase, a feature known in marine elasmobranchs and toadfishes, indicates the evolutionary position of H. fossilis to be different from that of present day freshwater teleosts.     

Enhanced cellular immunity in macaques following a novel peptide immunotherapy

Advances in treating and preventing AIDS depend on understanding how human immunodeficiency virus (HIV) is eliminated in vivo and on the manipulation of effective immune responses to HIV. During the development of assays quantifying the elimination of fluorescent autologous cells coated with overlapping 15-mer simian immunodeficiency virus (SIV) or HIV-1 peptides, we made a remarkable observation: the reinfusion of macaque peripheral blood mononuclear cells, or even whole blood, pulsed with SIV and/or HIV peptides generated sharply enhanced SIV- and HIV-1-specific T-cell immunity. Strong, broad CD4+- and CD8+-T-cell responses could be enhanced simultaneously against peptide pools spanning 87% of all SIV- and HIV-1-expressed proteins-highly desirable characteristics of HIV-specific immunity. De novo hepatitis C virus-specific CD4+- and CD8+-T-cell responses were generated in macaques by the same method. This simple technique holds promise for the immunotherapy of HIV and other chronic viral infections.     

Identification of Molecular Markers Associated with Alteration of Receptor-Binding Specificity in a Novel Genotype of Highly Pathogenic Avian Influenza A(H5N1) Viruses Detected in Cambodia in 2013

Human infections with influenza A(H5N1) virus in Cambodia increased sharply during 2013. Molecular characterization of viruses detected in clinical specimens from human cases revealed the presence of mutations associated with the alteration of receptor-binding specificity (K189R, Q222L) and respiratory droplet transmission in ferrets (N220K with Q222L). Discovery of quasispecies at position 222 (Q/L), in addition to the absence of the mutations in poultry/environmental samples, suggested that the mutations occurred during human infection and did not transmit further.     

Performance of the CareStart™ G6PD deficiency screening test, a point-of-care diagnostic for primaquine therapy screening

Development of reliable, easy-to-use, rapid diagnostic tests (RDTs) to detect glucose-6-phosphate dehydrogenase (G6PD) deficiency at point of care is essential to deploying primaquine therapies as part of malaria elimination strategies. We assessed a kit under research and development called CareStart? G6PD deficiency screening test (Access Bio, New Jersey, USA) by comparing its performance to quantitative G6PD enzyme activity using a standardized spectrophotometric method ('gold standard'). Blood samples (n?=?903) were collected from Cambodian adults living in Pailin province, western Cambodia. G6PD enzyme activities ranged from 0 to 20.5 U/g Hb (median 12.0 U/g Hg). Based on a normal haemoglobin concentration and wild-type G6PD gene, the normal values of G6PD enzymatic activity for this population was 3.6 to 20.5 U/g Hg (95(th) percentiles from 5.5 to 17.2 U/g Hg). Ninety-seven subjects (10.7%) had <3.6 U/g Hg and were classified as G6PD deficient. Prevalence of deficiency was 15.0% (64/425) among men and 6.9% (33/478) among women. Genotype was analyzed in 66 G6PD-deficient subjects and 63 of these exhibited findings consistent with Viangchang genotype. The sensitivity and specificity of the CareStart? G6PD deficiency screening test was 0.68 and 1.0, respectively. Its detection threshold was <2.7 U/g Hg, well within the range of moderate and severe enzyme deficiencies. Thirteen subjects (1.4%, 12 males and 1 female) with G6PD enzyme activities <2 U/g Hg were falsely classified as "normal" by RDT. This experimental RDT test here evaluated outside of the laboratory for the first time shows real promise, but safe application of it will require lower rates of falsely "normal" results.     

Bioprospecting and indexing the microalgal diversity of different ecological habitats of India

Our study reports the collection, biodiversity analyses, isolation and identification of microalgae from different habitats of India. Cyanophyceae and Chlorophyceae were the most dominant algal groups recorded, with the highest number being recorded for non-heterocystous cyanobacteria (48), followed by 44 unicellular forms. Sagar Island, Sunderbans recorded the greatest number of algae, and unicellular/colonial green algae were present in all the samples. Shannon’s Diversity Index was highest in Koikhali, Sunderbans, followed by Rushikulya River, Odisha. Selective enrichment, purification through serial dilution followed by plating and regular observations led to the isolation of sixteen strains. Identification was done by using microscopic observations, supported with standard monographs and classified as belonging to seven genera (Chlorella, Chlorococcum, Kirchneria, Scenedesmus, Chlamydomonas, Tetracystis and Ulothrix). 18S rDNA sequencing was undertaken for four strains. The set of sixteen strains were screened under standard cultural conditions for their growth kinetics and Chlorella sorokiniana MIC-G5, followed by Chlorella sp. MIC-G4 exhibited the highest growth rates. The strain Chlorococcum sp. MIC-G2 recorded highest chlorophyll, while MIC-G3 ranked highest for carbohydrates. The study aided in identifying the dominant microalgae in the diverse habitats and characterizing their growth rate and carbohydrate content, providing a valuable germplasm for further utilization in agriculture and industry.