Role of pre-existing immunity in driving the dengue virus serotype 2 genotype shift in the Philippines: A retrospective analysis of serological data.

Objective: The invasion of dengue virus (DENV)-2 Cosmopolitan genotype into the Philippines, where the Asian II genotype previously circulated challenges the principle of dengue serotype-specific immunity. Assessment of antibodies in this population may provide a mechanistic basis for how new genotypes emerge in dengue-endemic areas.

Methods: We evaluated the neutralizing antibody (nAb) and antibody-dependent enhancement (ADE) responses against the two genotypes using archived serum samples collected from 333 patients with confirmed dengue in Metro Manila, Philippines, before, during, and after the introduction of the Cosmopolitan genotype.

Saliva as alternative to naso-oropharyngeal swab for SARS-CoV-2 detection by RT-qPCR: a multicenter cross-sectional diagnostic validation study.

Saliva has been demonstrated as feasible alternative to naso-oropharyngeal swab (NOS) for SARS-CoV-2 detection through reverse transcription quantitative/real-time polymerase chain reaction (RT-qPCR). This study compared the diagnostic agreement of conventional NOS, saliva with RNA extraction (SE) and saliva without RNA extraction (SalivaDirect) processing for RT-qPCR in identifying SARS-CoV-2. All techniques were also compared, as separate index tests, to a composite reference standard (CRS) where positive and negative results were defined as SARS-CoV-2 detection in either one or no sample, respectively.

A Preliminary Investigation on the Antiviral Activities of the Philippine Marshmint (Mentha arvensis) Leaf Extracts against Dengue Virus Serotype 2 In Vitro.

In this study, we investigated the antiviral activity of lyophilized crude leaf extracts of the Philippine marshmint (Mentha arvensis L., commonly called yerba buena) against DENV-2 in vitro. The plant specimen was authenticated by DNA barcoding analysis using standard primers for amplification of rbcL, matK, ITS1, ITS2 and trnH-psbA.

An Epidemic of Dengue Virus Serotype-4 during the 2015 - 2017: the Emergence of a Novel Genotype IIa of DENV-4 in the Philippines.

Volume 72 no 6, p.413-419, 2019. Page 418, Acknowledgments "We would like to thank all staff and members of the Department of Virology, NEKKEN, Nagasaki University, Japan for providing technical support and advice.

An Epidemic of Dengue Virus Serotype-4 during the 2015 - 2017: the Emergence of a Novel Genotype IIa of DENV-4 in the Philippines.

Dengue remains a major public health problem in the Philippines. In this study, we determined the circulating dengue serotypes in the Philippines during the 2015-2017 outbreaks using a total of 678 serum samples from 537 individual dengue patients. Following an increase in the number of DENV-4 patients in recent years, we conducted a comprehensive molecular and epidemiology analysis on the DENV-4 strains isolated recently in the Philippines.

Hybrid Vibrio cholerae El Tor lacking SXT identified as the cause of a cholera outbreak in the Philippines.

Unlabelled: Cholera continues to be a global threat, with high rates of morbidity and mortality. In 2011, a cholera outbreak occurred in Palawan, Philippines, affecting more than 500 people, and 20 individuals died. Vibrio cholerae O1 was confirmed as the etiological agent.

Complete genome sequence of chikungunya virus isolated in the Philippines.

Chikungunya virus is an alphavirus of the Togaviridae family, which causes a febrile illness with arthralgia in humans. We report here on the complete genome sequence of chikungunya virus strain CHIKV-13-112A isolated from a patient in the Philippines who was suspected to have dengue virus. Phylogenetic analysis revealed that the strain is of the Asian genotype.

Association of glutathione S-transferase T1 and M1 genotypes with chronic liver diseases among Filipinos.

The glutathione S-transferase (GST) supergene family is made up of four gene families responsible for the biotransformation of drugs and other xenobiotics. Genetic variations in this supergene family influence individual detoxification levels and may contribute to the development of cancer. A hospital-based case-control study was conducted to evaluate the association between GST polymorphism among Filipino patients positive for hepatitis B virus (HBV DNA) and clinically diagnosed as either with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma as well as normal individuals negative for HBV infection.

Platelet apoptosis and apoptotic platelet clearance by macrophages in secondary dengue virus infections.

Background: The mechanisms of thrombocytopenia and platelet phagocytosis in dengue illness are not fully understood.

Methods: A prospective hospital-based study was conducted to examine the relationships between platelet counts, serum thrombopoietin (TPO) levels, and platelet apoptosis and phagocytosis in 81 patients with secondary dengue virus (DV) infections and 38 healthy volunteers. The apoptosis and phagocytosis of cultured platelets after exposure to DV were also examined.

Comparison of Cytotoxic Activity of Anticancer Drugs against Various Human Tumor Cell Lines Using In Vitro Cell-Based Approach.

Chemotherapy is the main treatment modality for certain types of cancer. It is important to monitor and ensure that these chemotherapeutic drugs are potent and effective prior to patient administration. The objective of the study is to evaluate the cytotoxic activity and potency of selected commercially available generic anticancer drugs in comparison with originator using various human cancer cell lines in an in vitro cell-based assay.

Shotgun genome sequence of a Yersinia enterocolitica isolate from the Philippines.

The first shotgun genome sequence of a microbial pathogen from the Philippines is reported. Yersinia enterocolitica subsp. palearctica strain PhRBD_Ye1 is the first Y.

Flow cytometric analysis of dengue virus-infected cells in peripheral blood.

With the development of permeabilization techniques in flow cytometry and the availability of various monoclonal antibodies (MAbs) that specifically bind with cell surface and intracellular antigens, it is now possible to use flow cytometric assay to identify dengue virus (DEN) infected cells in peripheral blood. Blood samples were analyzed using phycoerythrin (PE) labeled anti-CD3, anti-CD14, anti-CD16, and anti-CD19 antibodies and Alexa Fluor 488 labeled anti-flavivirus monoclonal antibody (MAb) 6B6C-1. The predominant DEN-infected cells were CD19+ in this study.

Development and evaluation of a fluorogenic real-time RT-PCR for the detection of dengue 3 virus.

A dengue-3-specific real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was developed using the novel Light Upon eXtension (LUX™) fluorogenic technology. A labeled forward primer and a standard reverse primer that target a conserved region within the non-structural 1 (NS1) gene of dengue 3 strains were designed. The dengue-3-specific assay did not recognize other dengue serotypes and related flaviviruses.

Evaluation of a dengue IgG indirect enzyme-linked immunosorbent assay and a Japanese encephalitis IgG indirect enzyme-linked immunosorbent assay for diagnosis of secondary dengue virus infection.

To establish a new method for the diagnosis of dengue secondary infection, 187 serum samples from the patients with dengue secondary infection, 40 serum samples from the patients with dengue primary infection, and 44 serum samples from the healthy volunteers were tested using the dengue IgG indirect enzyme-linked immunosorbent assay (DEN IgG ELISA). The results of the test were compared with those from the dengue hemagglutination inhibition (DEN HI) test, which has been recommended as the gold standard by the World Health Organization (WHO, 1997). Japanese encephalitis IgG indirect ELISA (JE IgG ELISA) was also performed to measure anti-flavivirus IgG, which cross-reacts with the Japanese encephalitis virus, to test the possibility of an alternative to DEN IgG ELISA.

Isolation and characterization of two phenotypically distinct dengue type-2 virus isolates from the same dengue hemorrhagic Fever patient.

Dengue is the one of the most prevalent arthropod-borne viral diseases. Dengue virus circulates between humans and mosquitoes, and causes a wide range of disease in humans. To elucidate the link between the cell tropism of dengue virus and its pathogenesis, peripheral blood cells of infected patients were analyzed by flow cytometry.

Increased phagocytosis of platelets from patients with secondary dengue virus infection by human macrophages.

The relationship between the percent phagocytosis of platelets by differentiated THP-1 cells was examined using flowcytometry and the peripheral platelet counts as well as platelet-associated IgG (PAIgG) in 36 patients with secondary dengue virus (DV) infections. The percent phagocytosis and the levels of PAIgG were significantly increased in these patients during the acute phase compared with the healthy volunteers. The increased percent phagocytosis and PAIgG found during the acute phase significantly decreased during the convalescent phase.

Antigen sandwich ELISA predicts RT-PCR detection of dengue virus genome in infected culture fluids of Aedes albopictus C6/36 cells.

Antigen detection by sandwich ELISA was evaluated to predict RT-PCR detection of dengue viral genome in infected culture fluid of Aedes albopictus clone C6/36 cells. Serum specimens collected from dengue patients within 5 days from onset of fever in 2 hospitals in Metro Manila, Philippines, were inoculated into C6/36 cells, and incubated at 28 degrees C. A total of 282 infected culture fluid specimens were harvested and examined by sandwich ELISA and RT-PCR to detect dengue viral antigen and genome, respectively.

Lack of efficacy of high-dose intravenous immunoglobulin treatment of severe thrombocytopenia in patients with secondary dengue virus infection.

Because most cases of secondary dengue virus infection are associated with an increased level of platelet-associated IgG, a high dose of intravenous immunoglobulin (IVIG) may have an effect on the development of severe thrombocytopenia in this disease. A randomized, controlled study was conducted with two treatment groups consisting of a treatment (IVIG) group (n = 15) and a non-treatment (non-IVIG) group (n = 16) to determine whether a high dose of IVIG is effective in hastening the recovery from thrombocytopenia in patients with secondary dengue virus infection. No significant difference was found in the baseline demographic data between the two groups.

Molecular epidemiology of dengue 2 viruses in the Philippines: genotype shift and local evolution.

The pre-membrane (prM) and envelope (E) genes of 41 viruses isolated from dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) patients from 1995 to 2002 were sequenced to determine the genetic variability of dengue 2 (DENV 2) viruses in the Philippines. The envelope sequence data were compared with a global sample of DENV 2 obtained from GenBank. Phylogenetic analysis revealed that two distinct genotypes, Asian 2 and Cosmopolitan, are currently circulating locally, each with the potential to cause severe hemorrhagic disease.

Correlation between increased platelet-associated IgG and thrombocytopenia in secondary dengue virus infections.

Although the public health impact of dengue is increasing rapidly, the mechanism of thrombocytopenia in this disease remains unknown. To elucidate this mechanism, the relationship between platelet-associated IgG (PAIgG) and platelet count in 53 patients in the acute phase of secondary dengue virus infection was investigated in a prospective-hospital-based study. A significant inverse correlation between the two parameters was found in these patients, while no correlation was observed in healthy volunteers.