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Four endemic human coronaviruses (HCoV), HCoV-229E, HCoV-NL63, HCoV-HKU1, and HCoV-OC43, are closely related to SARS-CoV-2. These coronaviruses are known to infect humans living in temperate areas, including children under 5 years old; however, the seroprevalence of four HCoVs among children in tropical areas, including the Philippines, remains unclear. This study aimed to assess the prevalence of antibodies against four HCoVs and to determine the reactivity and neutralization of these antibodies against SARS-CoV-2 among children in the Philippines. A total of 315 serum samples collected from 2015 to 2018, before the emergence of SARS-CoV-2, in Biliran island, Philippines, were tested for the presence of antibodies against four HCoVs and SARS-CoV-2 using recombinant spike ectodomain proteins by IgG-enzyme-linked immunosorbent assay (ELISA). Reactivity to and neutralization of SARS-CoV-2 were also investigated. The seroprevalence of the four HCoVs was 63.8% for HCoV-229E, 71.4% for HCoV-NL63, 76.5% for HCoV-HKU1, and 83.5% for HCoV-OC43 by ELISA. Age group analysis indicated that seropositivity to all HCoVs reached 80% by 2-3 years of age. While 69/315 (21.9%) of the samples showed reactive to SARS-CoV-2, almost no neutralization against SARS-CoV-2 was detected using neutralization assay. Reactivity of antibodies against SARS-CoV-2 spike protein obtained by ELISA may not correlate with neutralization capability., (© 2023. The Author(s).)

Objectives: Human adenoviruses (HAdV) are known to cause a wide range of diseases including acute respiratory infections, conjunctivitis, and acute gastroenteritis. In this study, we aimed to determine the serotypes of HAdV in patients with influenza-like illness (ILI) in the Philippines from 2006-2012 and to describe the demographic and epidemiological characteristics of patients who tested positive for HAdV., Methods: Between 2006 and 2012, the Philippine National Influenza Centre detected HAdV in 1294 samples of patients with ILI. Serotype determination was done in select samples using microneutralization, polymerase chain reaction (PCR), and sequencing methods., Results: A total of 8 serotypes were identified (HAdV 1-7 and 11), with HAdV-2 (27.8%), and HAdV-3 (27.8%) being the most prevalent. The majority of HAdV infections were found in children below 5 years of age (79.9%)., Conclusions: The identification of HAdV circulating serotypes may serve as guide for designing disease intervention and control strategies and will provide important information regarding the contribution of this virus to respiratory infections, particularly in children, which remain a public health burden in the Philippines., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Lower respiratory tract infection (LRTI) is an important cause of morbidity and mortality in infants and young children. However, the etiological role of viruses and the timing of developing LRTI are not well defined., Methods: We analyzed the data of a prospective cohort study in the Philippines as a birth cohort. We detected LRTI among children who visited healthcare facilities with respiratory symptom, and collected nasopharyngeal swabs for virus detection. We analyzed the incidence rates (IRs) and cumulative proportion of LRTI and severe LRTI by age group and each virus detected., Results: A total of 350 LRTI episodes were observed from 473 child-years yielded from 419 children. The IRs of LRTI were 70.8, 70.7, and 80.8 per 100 child-years for 0-5, 6-11, and 12-23 months of age, respectively. By 12 months of age, 45% of children developed LRTI at least once. Rhinovirus and respiratory syncytial virus were the most frequently detected viruses in all age groups. However, the IRs of influenza virus were low especially at 0-5 months of age., Conclusions: We identified various patterns of age-specific IRs of LRTI and severe LRTI for different viruses, which should be considered to establish more effective interventions including vaccinations., (© 2022. The Author(s).)

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection worldwide, but reports of temporal changes in the risk of transmission among close contacts has been scarce. This study aimed to examine an association between the viral load trajectory and transmission risk to develop a better control strategy for the disease spread. We conducted a household-based prospective cohort study in Biliran Province, the Philippines, and enrolled 451 participants to observe the development of acute respiratory infection. Including the cases found at the health-care facility, we analyzed the data of viral loads with symptom records obtained from 172 followed participants who had household member positive for RSV with a rapid test during an RSV outbreak in 2018-2019. We developed a model estimating a temporal change in the viral shedding from the infection and evaluated transmission dynamics. We found that most transmission events occurred within approximately 7 days of the household exposure, including potential presymptomatic transmissions. The inferred risk of infection among those younger than 5 years was 3.5 times higher than that of those older than 5 years. This finding suggested that the initial week after the household exposure is particularly important for preventing RSV spread., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.)

Objectives: Viral acute respiratory infection (ARI) remains a major global health problem, especially among children in low- and middle-income countries. The study was conducted to reveal aetiological significance of respiratory viruses among both non-hospitalized and hospitalized children., Methods: A cohort study of children with ARI at the household, primary healthcare facility, and hospital levels was conducted alongside a hospital-based study including non-cohort children from 2014 to 2016 in the Philippines. The ARI cases were recorded at households and healthcare facilities, and a clinical investigation was performed. Nasopharyngeal swabs were collected from the symptomatic children and tested for respiratory viruses via polymerase chain reaction. Then, the association between healthcare facility utilization and viral detection was investigated., Results: Overall, 18,514 ARI cases were enrolled in the cohort study, and samples were collected from 4735 of these cases. The hospital-based study detected 648 ARI cases, all of which were sampled. Rhinovirus (22.2%; 1052/4735) was most frequently detected followed by respiratory syncytial virus (12.0%; 566/4735). Enterovirus (adjusted odds ratio, 1.8; 95% confidence interval, 1.1-2.8), human metapneumovirus (2.1, 1.4-3.2), rhinovirus (2.1, 1.8-2.6), and respiratory syncytial virus (1.6, 1.2-1.9) were significantly more prevalent in the ARI cases at healthcare facilities than in those in households. Of all ARI cases, 0.6% required hospitalization while 1.8% were hospitalized among the respiratory syncytial virus-positive cases (3.8, 3.0-4.9)., Conclusions: We determined the prevalence of respiratory viruses among children with ARIs at the household, primary healthcare facility, and hospital levels and the association with clinical characteristics. In particular, we discovered a significant disease burden and impact of respiratory syncytial virus infections as well as a considerable aetiological implication of rhinovirus infections., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Respiratory syncytial virus (RSV) is one of the main viral causes of lower respiratory tract illness (LRTI), especially in young children. RSV vaccines, including maternal and infant vaccines, are under development; however, more epidemiological studies are needed to develop effective vaccination strategies., Objectives: To estimate detailed age-specific incidence rates and severity of RSV-associated LRTI (RSV-LRTI) using data from a community-based prospective cohort study in the Philippines., Patients/methods: Cohort children who visited health facilities due to acute respiratory symptoms were identified, and nasopharyngeal swabs were collected to detect RSV. The severity of RSV-LRTI was assessed using the severity definition proposed by the World Health Organization. Risk factors for developing RSV-LRTI and contribution of SpO 2 measurement were also evaluated., Results: A total of 395 RSV episodes which occurred in children aged 2-59 months were categorised as 183 RSV-LRTI, 72 as severe RSV-LRTI and 29 as very severe RSV-LRTI. Children aged 3-5 months had the highest incidence rate of RSV-LRTI, at 207.4 per 1000 child-years (95% CI: 149.0-279.5). Younger age group, place of living and low educational level of caregivers were associated with developing RSV-LRTI. Clinical manifestations had low levels of agreement with hypoxaemia as measured by pulse oximeter., Conclusion: The highest burden of RSV was observed in young infants aged 3-5 months, whereas the burden was also high in those aged 12-20 months. Future vaccination strategies should consider the protection of older children, especially those aged one year, as well as young infants., (© 2019 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.)

Objective: Pneumonia remains the leading cause of hospitalisations and deaths among children aged <5 years. Diverse respiratory pathogens cause acute respiratory infections, including pneumonia. Here, we analysed viral and bacterial pathogens and risk factors associated with death of hospitalised children., Design: A 9-year case series study., Setting: Two secondary-care hospitals, one tertiary-care hospital and one research centre in the Philippines., Participants: 5054 children aged <5 years hospitalised with severe pneumonia., Methods: Nasopharyngeal swabs for virus identification, and venous blood samples for bacterial culture were collected. Demographic, clinical data and laboratory findings were collected at admission time. Logistic regression analyses were performed to identify the factors associated with death., Results: Of the enrolled patients, 57% (2876/5054) were males. The case fatality rate was 4.7% (238/5054), showing a decreasing trend during the study period (p<0.001). 55.0% of the patients who died were either moderately or severely underweight. Viruses were detected in 61.0% of the patients, with respiratory syncytial virus (27.0%) and rhinovirus (23.0%) being the most commonly detected viruses. In children aged 2-59 months, the risk factors significantly associated with death included age of 2-5 months, sensorial changes, severe malnutrition, grunting, central cyanosis, decreased breath sounds, tachypnoea, fever (≥38.5°C), saturation of peripheral oxygen <90%, infiltration, consolidation and pleural effusion on chest radiograph.Among the pathogens, adenovirus type 7, seasonal influenza A (H1N1) and positive blood culture for bacteria were significantly associated with death. Similar patterns were observed between the death cases and the aforementioned factors in children aged <2 months., Conclusion: Malnutrition was the most common factor associated with death and addressing this issue may decrease the case fatality rate. In addition, chest radiographic examination and oxygen saturation measurement should be promoted in all hospitalised patients with pneumonia as well as bacteria detection to identify patients who are at risk of death., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality among adults worldwide. However, the distribution of the etiology of CAP varies from one country to another, with limited data from rural areas., Methods: A prospective hospital-based study on adult CAP was conducted in Leyte, Central Philippines from May 2010 to May 2012. Blood, sputum, and nasopharyngeal samples obtained from patients were used to identify pathogens using standard microbiological culture methods and PCR., Results: Of the 535 patients enrolled, 38% were younger than 50 years old. More than half of the patients had an underlying disease, including pulmonary tuberculosis (22%). The detection rate was higher for bacteria (40%) than viruses (13%). Haemophilus influenzae (12%) was the most commonly detected bacterium and influenza virus (5%) was the most commonly detected virus. The proportion of CAP patients with Mycobacterium tuberculosis infection was higher in the younger age group than in the older age group. Among CAP patients, 14% died during hospitalization, and drowsiness on admission and SpO 2 <90% were independent risk factors for mortality., Conclusions: Bacterial infections contribute substantially to the number of hospitalizations among CAP patients in rural Philippines. This study also highlights the importance of treatment of tuberculosis in reducing the burden of adult CAP in the country., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Acute respiratory infection (ARI) is of great concern in public health. It remains unclear whether viral infections can affect the host's susceptibility to subsequent ARIs., Methods: A prospective cohort study on ARIs of children below 5 years old was conducted in the Philippines from 2014 to 2016. The respiratory symptoms were recorded daily, and nasopharyngeal swabs were collected at both household and health facilities. The specimens were tested for respiratory viruses. We then determined whether viral etiology was associated with the severity of the present ARI and whether previous viral infections was associated with subsequent ARIs., Results: A total of 3851 children and 16337 ARI episodes were enrolled and recorded, respectively. Samples were collected from 24% of all ARI episodes; collection rate at the healthcare facilities was 95%. Enterovirus D68, rhinovirus species C, and respiratory syncytial virus were significantly associated with severe ARIs. The risk for subsequent ARIs was significantly enhanced after infections with adenovirus, influenza A virus, parainfluenza virus type 4, and rhinovirus species C., Conclusions: This study revealed that viral etiology plays a significant role in the severity of the present ARI and that viral infection affects the host's susceptibility to subsequent ARIs.

Background: Human respiratory syncytial virus (RSV) is the leading cause of severe acute respiratory infection in infants and young children, which is characterized by repeated infections. However, the role of amino acid substitutions in repeated infections remains unclear. Hence, this study aimed to elucidate the genetic characteristics of RSV in children with repeated infections using molecular analyses of F and G genes., Methods: We conducted a cohort study of children younger than 5 years in the Philippines. We collected nasopharyngeal swabs from children with acute respiratory symptoms and compared F and G sequences between initial and subsequent RSV infections., Results: We examined 1802 children from May 2014 to January 2016 and collected 3471 samples. Repeated infections were observed in 25 children, including 4 with homologous RSV-B reinfections. Viruses from the 4 pairs of homologous reinfections had amino acid substitutions in the G protein mostly at O-glycosylation sites, whereas changes in the F protein were identified at antigenic sites V (L173S) and θ (Q209K), considered essential epitopes for the prefusion conformation of the F protein., Conclusions: Amino acid substitutions in G and F proteins of RSV-B might have led to antigenic changes, potentially contributing to homologous reinfections observed in this study.

The local and global transmission dynamics of influenza B virus is not completely understood mainly because of limited epidemiological and sequence data for influenza B virus. Here we report epidemiological and molecular characteristics of influenza B viruses from 2010 to 2013 in Leyte Island, Philippines. Phylogenetic analyses showed global dissemination of the virus among both neighboring and distant areas. The analyses also suggest that southeast Asia is not a distributor of influenza B virus and can introduce the virus from other areas. Furthermore, we found evidence on the local persistence of the virus over years in the Philippines. Taken together, both local persistence and global dissemination play a significant role in the circulation of influenza B virus., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Human respiratory syncytial virus (HRSV) is a major cause of acute lower respiratory tract infections in infants and children worldwide. We performed molecular analysis of HRSV among infants and children with clinical diagnosis of severe pneumonia in four study sites in the Philippines, including Biliran, Leyte, Palawan, and Metro Manila from June 2012 to July 2013. Nasopharyngeal swabs were collected and screened for HRSV using real-time polymerase chain reaction (PCR). Positive samples were tested by conventional PCR and sequenced for the second hypervariable region (2nd HVR) of the G gene. Among a total of 1,505 samples, 423 samples were positive for HRSV (28.1%), of which 305 (72.1%) and 118 (27.9%) were identified as HRSV-A and HRSV-B, respectively. Two genotypes of HRSV-A, NA1 and ON1, were identified during the study period. The novel ON1 genotype with a 72-nucleotide duplication in 2nd HVR of the G gene increased rapidly and finally became the predominant genotype in 2013 with an evolutionary rate higher than the NA1 genotype. Moreover, in the ON1 genotype, we found positive selection at amino acid position 274 (p<0.05) and massive O- and N-glycosylation in the 2nd HVR of the G gene. Among HRSV-B, BA9 was the predominant genotype circulating in the Philippines. However, two sporadic cases of GB2 genotype were found, which might share a common ancestor with other Asian strains. These findings suggest that HRSV is an important cause of severe acute respiratory infection among children in the Philippines and revealed the emergence and subsequent predominance of the ON1 genotype and the sporadic detection of the GB2 genotype. Both genotypes were detected for the first time in the Philippines.

Background: Human sapovirus (SaV) is a causative agent of acute gastroenteritis. Recently, SaV detection has been increasing worldwide due to the emerging SaV genotype I.2. However, SaV infection has not been reported in the Philippines., Objectives: To evaluate the prevalence and genetic diversity of SaV in hospitalized children aged less than 5 years with acute gastroenteritis., Study Design: Stool samples were collected from children with acute gastroenteritis at three hospitals in the Philippines from June 2012 to August 2013. SaV was detected by reverse transcription real-time PCR, and the polymerase and capsid gene sequences were analyzed. Full genome sequencing and recombination analysis were performed on possible recombinant viruses., Results: SaV was detected in 7.0% of the tested stool samples (29/417). In 10 SaV-positive cases, other viruses were also detected, including rotavirus (n=6), norovirus (n=2), and human astrovirus (n=2). Four known SaV genotypes (GI.1 [7], GI.2 [2], GII.1 [12], and GV [2]) and one novel recombinant (n=3) were identified by polymerase and capsid gene sequence analysis. Full genome sequencing revealed that the 5' nontranslated region (NTR) and nonstructural protein region of the novel recombinant were closely related to the GII.1 Bristol/98/UK variant, whereas the structural protein region and 3' NTR were closely related to the GII.4 Kumamoto6/Mar2003/JPN variant., Discussion and Conclusions: SaV was regularly detected in hospitalized children due to acute gastroenteritis during the study period. A novel recombinant, SaV GII.1/GII.4, was identified in three cases at two different study sites., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Large outbreaks of measles occurred in the Philippines in 2010 and 2011. Genetic analysis was performed to identify the genotype of measles virus (MeV) that was responsible for the large outbreaks., Methods: A total of 114 representative MeVs that were detected in the Philippines from 2008 to 2011 were analyzed by sequencing the C-terminal region of nucleocapsid (N) gene and partial hemagglutinin (H) gene and by inferring the phylogenetic trees., Results: Genetic analysis showed that genotype D9 was the predominant circulating strain during the 4-year study period. Genotype D9 was detected in 23 samples (92%) by N gene sequencing and 93 samples (94%) by H gene analysis. Sporadic cases of genotype G3 MeV were identified in 2 samples (8%) by N gene sequencing and 6 samples (6%) by H gene analysis. Genotype G3 MeV was detected mainly in Panay Island in 2009 and 2010. Molecular clock analysis of N gene showed that the recent genotype D9 viruses that caused the big outbreaks in 2010 and 2011 diverged from a common ancestor in 2005 in one of the neighboring Southeast Asian countries, where D9 was endemic. These big outbreaks of measles resulted in a spillover and were associated with genotype D9 MeV importation to Japan and the USA., Conclusion: Genotype D9 MeV became endemic and caused two big outbreaks in the Philippines in 2010 and 2011. Genotype G3 MeV was detected sporadically with limited geographic distribution. This study highlights the importance of genetic analysis not only in helping with the assessment of measles elimination program in the country but also in elucidating the transmission dynamics of measles virus.

This study aimed to determine the role of influenza-like illness (ILI) surveillance conducted on Leyte Island, the Philippines, including involvement of other respiratory viruses, from 2010 to 2013. ILI surveillance was conducted from January 2010 to March 2013 with 3 sentinel sites located in Tacloban city, Palo and Tanauan of Leyte Island. ILI was defined as fever ≥38°C or feverish feeling and either cough or running nose in a patient of any age. Influenza virus and other 5 respiratory viruses were searched. A total of 5,550 ILI cases visited the 3 sites and specimens were collected from 2,031 (36.6%) cases. Among the cases sampled, 1,637 (75.6%) were children aged <5 years. 874 (43.0%) cases were positive for at least one of the respiratory viruses tested. Influenza virus and respiratory syncytial virus (RSV) were predominantly detected (both were 25.7%) followed by human rhinovirus (HRV) (17.5%). The age distributions were significantly different between those who were positive for influenza, HRV, and RSV. ILI cases were reported throughout the year and influenza virus was co-detected with those viruses on approximately half of the weeks of study period (RSV in 60.5% and HRV 47.4%). In terms of clinical manifestations, only the rates of headache and sore throat were significantly higher in influenza positive cases than cases positive to other viruses. In conclusion, syndromic ILI surveillance in this area is difficult to detect the start of influenza epidemic without laboratory confirmation which requires huge resources. Age was an important factor that affected positive rates of influenza and other respiratory viruses. Involvement of older age children may be useful to detect influenza more effectively.

From November 2009 to December 2013 in the Philippines, 15 influenza C viruses were isolated, using MDCK cells, from specimens obtained from children with severe pneumonia and influenza-like illness (ILI). This is the first report of influenza C virus isolation in the Philippines. In addition, from January 2008 to December 2013, 7 influenza C viruses were isolated from specimens that were obtained from children with acute respiratory illness (ARI) in Sendai city, Japan. Antigenic analysis with monoclonal antibodies to the hemagglutinin-esterase (HE) glycoprotein showed that 19 strains (12 from the Philippines and 7 from Japan) were similar to the influenza C virus reference strain C/Sao Paulo/378/82 (SP82). Phylogenetic analysis of the HE gene showed that the strains from the Philippines and Japan formed distinct clusters within an SP82-related lineage. The clusters that included the Philippine and Japanese strains were shown to have diverged from a common ancestor around 1993. In addition, phylogenetic analysis of the internal genes showed that all strains isolated in the Philippines and Japan had emerged through reassortment events. The composition of the internal genes of the Philippine strains was different from that of the Japanese strains, although all strains were classified into an SP82-related lineage by HE gene sequence analysis. These observations suggest that the influenza C viruses analyzed here had emerged through different reassortment events; however, the time and place at which the reassortment events occurred were not determined., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Enterovirus D68 (EV-D68) has been recognized as an important cause of acute respiratory infections. Here we report the molecular epidemiology of EV-D68 in Philippines from 2013 to 2014; we found cases in areas affected by Typhoon Haiyan and found new strains in the country., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Human adenovirus (HAdV) serotype 7 is an important etiological agent of severe childhood pneumonia. The aim of this study was to define the role of HAdV7 and to describe its clinical and molecular epidemiological characteristics in the Philippines in 2011. HAdVs were detected by viral culture, and a partial region of hexon gene was sequenced. A total of 700 patients were enrolled, of which 22 (3.1%) died. Nine (1.3%) HAdV cases were confirmed, of which 7 were positive for HAdV7, 1 for HAdV3, and 1 for HAdV5. Among the 9 HAdV-positive cases, 4 (44%) with HAdV7 died. Molecular analysis revealed that all HAdV7 isolates were closely related to genome type h strains. This study demonstrated the significance of HAdV7 as an etiological agent of severe pediatric pneumonia with a high fatality rate. Hence, continuous monitoring is required to define the clinical and public health significance of HAdV7 infection.

Background: Detection of Enterovirus 68 (EV68) has recently been increased. However, underlying evolutionary mechanism of this increasing trend is not fully understood., Methods: Nasopharyngeal swabs were collected from 5,240 patients with acute respiratory infections in the Philippines from June 2009 to December 2011. EV68 was detected by polymerase chain reaction (PCR) targeting for 5' untranslated region (5'UTR), viral protein 1 (VP1), and VP4/VP2. Phylogenetic trees were generated using the obtained sequences., Results: Of the 5,240 tested samples, 12 EV68 positive cases were detected between August and December in 2011 (detection rate, 0.23%). The detection rate was higher among inpatients than outpatients (p<0.0001). Among VP1 sequences detected from 7 patients in 2011, 5 in lineage 2 were diverged from those detected in the Philippines in 2008, however, 2 in lineage 3 were not diverged from strains detected in the Philippines in 2008 but closely associated with strains detected in the United States. Combined with our previous report, EV68 occurrences were observed twice in the Philippines within the last four years., Conclusions: EV68 detections might be occurring in cyclic patterns, and viruses might have been maintained in the community while some strains might have been newly introduced.

Background: Human respiratory syncytial virus (HRSV) is the leading cause of acute lower respiratory tract infection in infants and young children. However, molecular characteristic of HRSV is still unknown in the Philippines., Objective: To describe the molecular epidemiology of circulating HRSV detected in the Philippines., Study Design: From May 2008 to April 2012, nasopharyngeal swabs were collected from infants and children aged between 7 days and 14 years who were hospitalized with severe pneumonia. HRSV was detected by nested PCR targeting M2 gene, and C-terminus of the G gene was sequenced for phylogenetic analysis., Result: Out of total 2150 samples, 19.3% (n = 415) were positive for HRSV, and 65.0% of them (n = 270) were identified as HRSV-A and 35.0% (n = 145) as HRSV-B. There were two major HRSV outbreaks: between June 2008 and February 2009, and between June and March 2012. Majority of HRSV strains detected during the former outbreak were HRSV-A (97.5%, 203/208) whereas during the later outbreak, both HRSV-A (54/158, 34.2%) and HRSV-B (104/158, 65.8%) were detected. All HRSV-A strains were classified as genotype NA1 and all HRSV-B as genotype BA, which had 60-nucleotide duplication in secondary hypervariable region of the G gene. Among HRSV-B positive samples, there were 2 distinct clusters with unique amino acid changes and low homology in compared to other strains in BA, suggesting emergence of new variant of HRSV-B., Conclusion: The study provides an overview of the genetic variation in circulating HRSV viruses in the Philippines along with identification of possibly a novel variant of HRSV-B., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Tohoku University Graduate School of Medicine has established the Tohoku-RITM Collaborative Research Center on Emerging and Re-emerging Diseases at Research Institute for Tropical Medicine (RITM) in the Philippines in 2008. Our aim of the center is to conduct operational researches, which can contribute to control of infectious diseases in the Philippines. Therefore most of our researches in the Philippines are being conducted in the fields. Main research themes include severe acute respiratory infections in children, influenza disease burden study, molecular epidemiology of rabies, and viral etiology of acute diarrhea. The study on severe acute respiratory infections in children in Leyte Island has recruited hospitalized cases with severe pneumonia. We showed that enterovirus 68 was one of important causative agents in severe pneumonia cases. We also conducted other analyses including molecular epidemiology of respiratory syncytial virus (RSV) and pathogenesis of human rhinoviruses (HRV). Based on these studies, we initiated more comprehensive researches in the Philippines since 2010.