Papers by Vicente Belizario
Encyclopedia of Parasitology
Philippine Journal of Science
The periodic collection of parasitologic and morbidity indicators is recommended by the World Hea... more The periodic collection of parasitologic and morbidity indicators is recommended by the World Health Organization (WHO) to monitor schistosomiasis (SCH) and soil-transmitted helminthiasis (STH) control programs. In 2017, the DOH-CHD VIII (Department of Health–Center for Health Development Region 8 Office) – in collaboration with UP-NTDSG (the University of the Philippines Neglected Tropical Diseases Study Group) – conducted a monitoring activity aimed at determining [1] the prevalence and intensity of SCH and STH; [2] seroprevalence of SCH; and [3] prevalence of stunting, underweight, wasting, and anemia in pre-school-age children (PSAC) and school-age children (SAC) in selected municipalities in the province of Northern Leyte, the Philippines as part of monitoring the local implementation of SCH and STH control programs. Stool samples were collected, processed using the Kato-Katz technique, and examined through microscopy. Blood specimens collected from SAC were tested for the pres...
Tropical Medicine and Infectious Disease
Tuberculosis (TB) is a chronic infectious disease that remains to be a primary health concern glo... more Tuberculosis (TB) is a chronic infectious disease that remains to be a primary health concern globally. The Philippines is among the top TB-burdened countries. Workplace TB prevention and control programs are essential to ensure the health and safety of workers and economic security. There remains a knowledge gap regarding the Philippine workplace TB prevention and control program implementation. This qualitative study involving key informant interviews reviewed the implementation of the workplace TB program in selected companies in a high TB burden region in Eastern Philippines. Results were presented under four themes in accordance with the components of the workplace TB policy: preventive strategies, medical management, data recording and reporting, and social policy. Various good practices, opportunities, and challenges in the implementation of the workplace TB program were identified. There is a need to strengthen the enforcement of policy across different components. Complianc...
Royal Society Open Science
Despite being one of the first countries to implement mass drug administration (MDA) for eliminat... more Despite being one of the first countries to implement mass drug administration (MDA) for elimination of lymphatic filariasis (LF) in 2001 after a pilot study in 2000, the Philippines is yet to eliminate the disease as a public health problem with 6 out of the 46 endemic provinces still implementing MDA for LF as of 2018. In this work, we propose a mathematical model of the transmission dynamics of LF in the Philippines and a control strategy for its elimination using MDA. Sensitivity analysis using the Latin hypercube sampling and partial rank correlation coefficient methods suggests that the infected human population is most sensitive to the treatment parameters. Using the available LF data in Caraga Region from the Philippine Department of Health, we estimate the treatment ratesr1andr2using the least-squares parameter estimation technique. Parameter bootstrapping showed small variability in the parameter estimates. Finally, we apply optimal control theory with the objective of min...
SSRN Electronic Journal, 2021
Schistosomiasis is a neglected tropical disease endemic in the Philippines, affecting 28 province... more Schistosomiasis is a neglected tropical disease endemic in the Philippines, affecting 28 provinces in 12 regions. This parasitic disease is caused by Schistosoma japonicum, a zoonotic parasite that infects other mammalian hosts aside from humans. In this study, a mathematical model is developed to describe the transmission of schistosomiasis in Agusan del Sur, Philippines and investigate control strategies that could lead to possible elimination of the disease. The model considers humans as definitive hosts, carabaos as reservoir hosts, and snails as intermediate hosts. Available schistosomiasis data from the Philippine Department of Health are utilized to estimate the transmission probability, contact rate between snails and humans, and infectivity from humans and carabaos to snails. Various intervention measures in mitigating the disease are explored under the framework of optimal control theory. The strategies include efforts to increase treatment coverage and compliance of mass ...
Southeast Asian Journal of Tropical Medicine and Public Health, 2018
Journal of Biosocial Science, 2022
Schistosomiasis japonica remains a public health concern in many areas of the Philippines. Period... more Schistosomiasis japonica remains a public health concern in many areas of the Philippines. Periodic Mass Drug Administration (MDA) to at-risk populations is the main strategy for morbidity control of schistosomiasis. Attaining MDA coverage targets is important for the reduction of morbidity and prevention of complications due to the disease, and towards achieving Universal Health Care. The study employed a qualitative case study design. Key informant interviews and focus group discussions were conducted to provide in-depth and situated descriptions of the contexts surrounding the implementation of MDA in two selected villages in known schistosomiasis-endemic provinces in Mindanao in the Philippines. Data analysis was done using the Critical Ecology for Medical Anthropology (CEMA) model coupled with the intersectionality approach. It was found that within various areas in the CEMA model, enabling as well as constraining factors have been encountered in MDA in the study settings. The ...
Journal of Health Research, 2019
Background and Objective: Schistosoma japonicum is the causative agent of schistosomiasis in the ... more Background and Objective: Schistosoma japonicum is the causative agent of schistosomiasis in the Philippines. Current diagnostics suffer from low sensitivity and accuracy, hence an accurate and reliable diagnosis of schistosomiasis is essential for its prevention and control. In this study, a PCR-based assay for the detection of Schistosoma japonicum for patient stool and serum samples was developed. Methodology: Three candidate primer sets targeting mitochondrial genes COX3, NAD4, and NAD5 were assessed. COX3 primer pair was used for the rest of the study for sensitivity, specificity, and performance testing. Lastly, the assay using COX3 primer pair was compared to Kato-Katz and circumoval precipitin test (COPT). Results: COX3 and NAD5 primers showed to be suitable for the assay as sequencing analyses gave high similarities of 96-98% for S. japonicum , while NAD4 showed no similarity to any organisms. The PCR-assay was shown to have a detection limit of 4 ng/ul DNA and is specific ...
Journal of Health Research, 2013
With the enactment of Republic Act 7719 (or National Blood Services Act) in 1994, all commercial ... more With the enactment of Republic Act 7719 (or National Blood Services Act) in 1994, all commercial blood banks have been phased out as they were implicated for providing unsafe and tainted blood supply in the Philippines. Instead, the same law has encouraged the voluntary non-remunerated donation of blood to ensure adequate, safe, affordable, and equitable supply of blood and blood products for Filipinos. Using a stratified random sampling proportionate to the amount of blood units produced in a year, a cross-sectional investigation was carried out to determine the current practices of blood service facilities (BSFs) in the Philippines. Specifically, the study aimed to (1) review Philippine policies and guidelines on blood services and compare them with international standards (2) identify and establish the type of BSF and their unit production as of 2011, and (3) determine the practices of BSFs on blood donation, testing, distribution, and release. There were a total of 308 BSFs cate...
Disaster Medicine and Public Health Preparedness, 2020
ABSTRACTObjectives:In the Philippines, morbidity control of soil-transmitted helminth (STH) infec... more ABSTRACTObjectives:In the Philippines, morbidity control of soil-transmitted helminth (STH) infections is done through mass drug administration (MDA) of anthelmintics to school-age children (SAC). In 2013, the Philippines was devastated by the deadliest cyclone ever recorded, Typhoon Haiyan. The study aimed to understand the impact of Typhoon Haiyan on the MDA of anthelmintics to SAC in the provinces of Capiz and Iloilo in the Philippines from the perspectives of local health and education officials.Methods:The study was conducted in the municipalities of Panay and Pilar in Capiz and the municipalities of Estancia and Sara in Iloilo, areas that were devastated by Typhoon Haiyan. Qualitative, semi-structured key informant interviews were conducted with 16 total participants, which included officials of the Department of Health, Department of Education, and concerned local government units. All interviews were transcribed verbatim and coded in an open, iterative manner. Codes were rev...
PLOS Neglected Tropical Diseases, 2021
Background Soil-transmitted helminths (STHs) are parasitic nematodes that inhabit the human intes... more Background Soil-transmitted helminths (STHs) are parasitic nematodes that inhabit the human intestine. They affect more than 1.5 billion people worldwide, causing physical and cognitive impairment in children. The global strategy to control STH infection includes periodic mass drug administration (MDA) based on the results of diagnostic testing among populations at risk, but the current microscopy method for detecting infection has diminished sensitivity as the intensity of infection decreases. Thus, improved diagnostic tools are needed to support decision-making for STH control programs. Methodology We developed a nucleic acid amplification test based on recombinase polymerase amplification (RPA) technology to detect STH in stool. We designed primers and probes for each of the four STH species, optimized the assay, and then verified its performance using clinical stool samples. Principal findings Each RPA assay was as sensitive as a real-time polymerase chain reaction (PCR) assay i...
Advances in Parasitology, 2020
Acta Medica Philippina, 2012
Acta Medica Philippina, 2014
Published scientific papers and monographs containing epidemiology of selected neglected parasiti... more Published scientific papers and monographs containing epidemiology of selected neglected parasitic diseases in the Philippines were retrieved and reviewed. International standards on diagnosis and quality assurance were gathered from journal articles and documents from the World Health Organization (WHO). Philippine policies and practices on diagnosis and quality assurance were obtained from the Department of Health (DOH), as well as key-informant interviews with the DOH Bureau of Health Facilities and Services (BHFS),
Pathogens and Global Health, 2020
Improving paragonimiasis surveillance, which is crucial for disease control, requires adopting ne... more Improving paragonimiasis surveillance, which is crucial for disease control, requires adopting new tools and techniques useful in mapping endemic areas. This study aimed to (1) develop a questionnaire to identify suspected paragonimiasis-endemic foci, (2) describe the epidemiology of paragonimiasis, and (3) evaluate Ziehl-Nielsen Staining technique (ZNS) in detecting Paragonimus ova. The questionnaire, which municipal health officers filled out, was based on proposed site inclusion criteria utilized in the integrated tuberculosis (TB)-paragonimiasis surveillance and control project. Newly deployed medical technologists in Zamboanga Region underwent training, which included laboratory diagnosis of paragonimiasis using preserved and fresh specimens and an integrated tuberculosis-paragonimiasis survey in nine selected barangays (villages). Paragonimiasis cases were found in seven out of the nine barangays identified by the questionnaire. Of the 373 patients, three (0.80%) were TBpositive, and 29 (7.77%) were paragonimiasis-positive. The highest paragonimiasis prevalence (27%) was found in Barangay Libato. Ziehl-Neelsen Staining technique (ZNS) correctly detected 8 out of the 29 samples positive (sensitivity-27.59%; 95% CI: 12.73-47.24%) and all the 334 samples negative (specificity-100%; 95% CI: 98.90-100%) for Paragonimus ova. The questionnaire may be improved by refining the inclusion criteria. In paragonimiasis-endemic areas, the ZNS and the NaOH concentration technique may be used for detecting Paragonimus ova. Modifying the ZNS, for instance by including a concentration step, may improve its sensitivity. The model for the integrated capacity building of health workers and surveillance and research demonstrated in this project may contribute to improving surveillance and control of paragonimiasis and other neglected tropical diseases.
Journal of helminthology, Jan 14, 2016
Haplorchis taichui is an intestinal heterophyid fluke that is pathogenic to humans. It is widely ... more Haplorchis taichui is an intestinal heterophyid fluke that is pathogenic to humans. It is widely distributed in Asia, with a particularly high prevalence in Indochina. Previous work revealed that the lack of gene flow between three distinct populations of Vietnamese H. taichui can be attributed to their geographic isolation with no interconnected river basins. To test the hypothesis that interconnected river basins allow gene flow between otherwise isolated populations of H. taichui, as previously demonstrated for another trematode, Opisthorchis viverrini, we compared the genetic structures of seven populations of H. taichui from various localities in the lower Mekong Basin, in Thailand and Laos, with those in Vietnam, using the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene. To determine the gene flow between these H. taichui populations, we calculated their phylogenetic relationships, genetic distances and haplotype diversity. Each population showed very low nucleotide d...
International Journal for Parasitology: Drugs and Drug Resistance, 2020
International Journal of One Health
Background and Aim: There have been limited capacity-building activities on One Health in the Phi... more Background and Aim: There have been limited capacity-building activities on One Health in the Philippines. To contribute to capacity development in One Health, the authors conducted the first short course on One Health in the country for health, allied health, and collaborating professionals. This study aimed to review the preparation and implementation of the One Health course and describe the challenges and opportunities of conducting the course during the coronavirus disease 2019 (COVID-19) pandemic. Materials and Methods: The course curriculum was developed by a multidisciplinary group of experts. The objectives for the course were as follows: (1) Describe the concept, scope, and applications of One Health; (2) identify social and economic factors influencing food security and safety, control of zoonoses, and combating antimicrobial resistance; and (3) describe the challenges and opportunities in applying the One Health approach to achieve better public health outcomes. Recruitm...
The designations employed and the presentation of the material in this publication do not imply t... more The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication. However, the published material is being distributed without warranty of any kind, either expressed or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use.
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Papers by Vicente Belizario