Yun-Hung Tu

Taipei Medical University

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Nemia L. Sucaldito

Department of Health

Julius Clemence R. Hafalla

London School of Hygiene & Tropical Medicine

Ferchito L. Avelino

Department of Health

Ava Kristy Sy

Research Institute for Tropical Medicine

Oliver J. Brady

London School of Hygiene & Tropical Medicine

Sebastian Funk

London School of Hygiene & Tropical Medicine

Carmencita D. Padilla

Tokushima University

Amado Tandoc

Research Institute for Tropical Medicine

Martin L. Hibberd

London School of Hygiene & Tropical Medicine

Joseph R. Biggs

London School of Hygiene & Tropical Medicine

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London School of Hygiene & Tropical Medicine

University of London

Taipei Medical University

National Institute of Infectious Diseases

Research Institute for Tropical Medicine

Nagasaki University

Peter Doherty Institute

University of the Philippines Manila

Institut Pasteur de Nha Trang

National Institute Of Hygiene And Epidemiology

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Additional file 7 of A serological framework to investigate acute primary and post-primary dengue cases reporting across the Philippines

Figshare (2020)

Joseph R. Biggs Ava Kristy Sy Oliver J. Brady Adam J. Kucharski Sebastian Funk

Additional file 7. Validation of A2 compared to the WHO gold standard method of determining dengue immune status. WHO immune classification: dengue immune status according to WHO guidelines. Blue: serological agreement. Red: Serological disagreement.

Primary (astronomy)

10.6084/m9.figshare.13294717

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Citations (0)

Additional file 8 of A serological framework to investigate acute primary and post-primary dengue cases reporting across the Philippines

Figshare (2020)

Joseph R. Biggs Ava Kristy Sy Oliver J. Brady Adam J. Kucharski Sebastian Funk

Additional file 8. Validation of A1 compared to the WHO gold standard method of determining dengue immune status. WHO immune classification: dengue immune status according to WHO guidelines. Blue: serological agreement. Red: Serological disagreement.

Primary (astronomy)

10.6084/m9.figshare.13294720

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Prevalence and Risk Factors for Intestinal Parasitic Infection in Schoolchildren in Battambang, Cambodia

American Journal of Tropical Medicine and Hygiene (2017)

Chien‐Wei Liao Kuan-Chih Chiu I-Chen Chiang Po-Ching Cheng Ting-Wu Chuang

Most intestinal parasitic infections (IPIs), commonly endemic in tropical resource-poor developing countries, are neglected tropical diseases. Parasitic infections and malnutrition are most commonly found in children. We determined the prevalence of IPIs and the risk factors in Battambang Province, northwestern Cambodia, from August to September 2015. This study collected 308 valid questionnaires and specimens from Dontri (173, 56.2%) and Kon Kaêk (135, 43.8%) primary schools. All stool samples were examined using Chang's Feces Examination Apparatus through the merthiolate-iodine-formaldehyde technique. Headache (259, 84.1%), recurrent cough (249, 80.8%), and abdominal pain (235, 76.3%) were the most common symptoms as detected from questionnaire investigation. A total of 155 students were positive for any parasite type; a single parasite type was observed in 97 students (31.5%), two types in 40 students (13.0%), three types in 14 students (4.6%), and four types in four students (1.3%). Nine gastrointestinal parasite species (three helminths and six protozoa) were identified in the stool samples. The most common parasites in schoolchildren were Giardia intestinalis (31.5%) and Entamoeba histolytica/dispar (17.5%). This is the first IPIs study, and more than half of the schoolchildren were infected with parasite species in Moung Russey District of Battambang Province. We found nine parasite species, including helminths and protozoa, and pathogenic protozoa were the main source of IPIs. Improving the detection method, sanitation facilities, and personal hygiene as well as utilizing combined drugs are all important measures to greatly reduce IPIs in Cambodian schoolchildren.

Trichuriasis

10.4269/ajtmh.16-0681

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A serological framework to investigate acute primary and post-primary dengue cases reporting across the Philippines

BMC Medicine (2020)

Joseph R. Biggs Ava Kristy Sy Oliver J. Brady Adam J. Kucharski Sebastian Funk

Abstract Background In dengue-endemic countries, targeting limited control interventions to populations at risk of severe disease could enable increased efficiency. Individuals who have had their first (primary) dengue infection are at risk of developing more severe secondary disease, thus could be targeted for disease prevention. Currently, there is no reliable algorithm for determining primary and post-primary (infection with more than one flavivirus) status from a single serum sample. In this study, we developed and validated an immune status algorithm using single acute serum samples from reporting patients and investigated dengue immuno-epidemiological patterns across the Philippines. Methods During 2015/2016, a cross-sectional sample of 10,137 dengue case reports provided serum for molecular (anti-DENV PCR) and serological (anti-DENV IgM/G capture ELISA) assay. Using mixture modelling, we re-assessed IgM/G seroprevalence and estimated functional, disease day-specific, IgG:IgM ratios that categorised the reporting population as negative, historical, primary and post-primary for dengue. We validated our algorithm against WHO gold standard criteria and investigated cross-reactivity with Zika by assaying a random subset for anti-ZIKV IgM and IgG. Lastly, using our algorithm, we explored immuno-epidemiological patterns of dengue across the Philippines. Results Our modelled IgM and IgG seroprevalence thresholds were lower than kit-provided thresholds. Individuals anti-DENV PCR+ or IgM+ were classified as active dengue infections (83.1%, 6998/8425). IgG− and IgG+ active dengue infections on disease days 1 and 2 were categorised as primary and post-primary, respectively, while those on disease days 3 to 5 with IgG:IgM ratios below and above 0.45 were classified as primary and post-primary, respectively. A significant proportion of post-primary dengue infections had elevated anti-ZIKV IgG inferring previous Zika exposure. Our algorithm achieved 90.5% serological agreement with WHO standard practice. Post-primary dengue infections were more likely to be older and present with severe symptoms. Finally, we identified a spatio-temporal cluster of primary dengue case reporting in northern Luzon during 2016. Conclusions Our dengue immune status algorithm can equip surveillance operations with the means to target dengue control efforts. The algorithm accurately identified primary dengue infections who are at risk of future severe disease.

Seroprevalence

Flavivirus

Immunoglobulin M

10.1186/s12916-020-01833-1

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Molecular approaches to deploy singlet oxygen in a Leishmania model as an unassailable biocide for disease mitigation and vector control

Frontiers in Tropical Diseases (2024)

Kwang Poo Chang Joseph M. Reynolds Dennis K. P. Ng Yun-Hung Tu Chia‐Kwung Fan

Singlet oxygen ( 1 O 2 ) is a potent biocide potentially deployable for integrated control of tropical diseases and their insect vectors. This very short-lived free radical is highly destructive of cellular molecules when generated intracellularly. Most organisms, including parasites and vectors, are defenseless against 1 O 2 except for plants, which produce it abundantly during photosynthesis, hence, the acquisition of specific mechanisms for its detoxification. In the presence of O 2 under physiological conditions, certain dyes or photosensitizers (PS), e.g., porphyrins and phthalocyanines (PC), are excitable by light to produce biocidal 1 O 2 . Its half-life is in the order of microseconds, necessitating its intracellular generation in order to harness its biocidal activity most effectively. This is achievable by loading cells with PS for excitation with light to produce 1 O 2 in situ . One example to achieve this is the genetic engineering of Leishmania to complement its inherent defects in porphyrin biosynthesis, resulting in cytosolic accumulation of abundant PS in the form of uroporphyrin 1 (URO). Another example is the chemical engineering of PC for hydrophilicity, thereby facilitating the endocytosis of such PS by cells. Leishmania loaded with cytosolic URO and endosomal PC are inactivated by the 1 O 2 produced via light-activation of these PS in the two different cell compartments. The inactivated Leishmania are nonviable, but have their natural vaccines and adjuvants well-preserved for prophylactic vaccination against experimental leishmaniasis. 1 O 2 -inactivated Leishmania is potentially useful to serve as a platform for the safe and effective delivery of transgenically add-on vaccines against malignant and viral diseases in experimental models. Hydrophilic and cationic PC were also shown experimentally to act as a new type of dim light-activable insecticides, i.e., their mosquito larvicidal activities with <µM LD 50 values. Similar results are expected by studying PC in additional laboratory insect models. A significant advantage has long been attributed to this type of insecticide, i.e., their aversion to a selection of genetic variants for resistance. An additional advantage of PC is their excitability to produce insecticidal 1 O 2 with deep-penetrating red or infrared light invisible to most insects, thereby potentially increasing the range and scope of targetable insect vectors.

Biocide

10.3389/fitd.2024.1306429

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Prevalence of Pediculus capitis in schoolchildren in Battambang, Cambodia

Journal of Microbiology Immunology and Infection (2017)

Chien‐Wei Liao Po-Ching Cheng Ting-Wu Chuang Kuan-Chih Chiu I-Chen Chiang

Pediculus capitis is the most common human ectoparasite. When it feeds on the blood through the scalp of its host, the anticoagulant in its saliva causes scalp inflammation and itching, and consequent scratching by the host causes further inflammation from bacterial infection. P. capitis infestation is currently a common parasitic dermatosis and a critical public health concern in underdeveloped countries.Through naked eye inspection of P. capitis on or in the hair from 323 school children in Cambodia.A total of 143 children (44.3%) were found to have P. capitis infestation. Univariate analysis revealed that girls had a significantly higher infection rate than boys. Overall, young aged schoolchildren (10 yrs old ≤) showed significantly higher infection rate than old aged schoolchildren (>10 yrs old). Groups stratified by time revealed that schoolchildren studied at the afternoon classes than morning classes in Tuol Prum Muoy Primary School had a significantly higher risk in acquisition of P. capitis infestation. Multivariate analysis results indicated that relative to the boys, the girls were at a significantly higher risk of contracting P. capitis infection. When stratified by inspection time with the Tuol Prum Muoy Primary School morning classes as the reference, the Tuol Prum Muoy Primary School afternoon classes exhibited a significantly higher risk of P. capitis infection.Primary school children in Cambodia have a high P. capitis infection rate and thus require effective treatment and prevention measures to treat symptoms and lower the infection rate.

Tinea Capitis

Pediculosis

10.1016/j.jmii.2017.09.003

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Citations (21)

Serological Evidence of Widespread Zika Transmission across the Philippines

Viruses (2021)

Joseph R. Biggs Ava Kristy Sy Oliver J. Brady Adam J. Kucharski Sebastian Funk

Zika virus (ZIKV) exposure across flavivirus-endemic countries, including the Philippines, remains largely unknown despite sporadic case reporting and environmental suitability for transmission. Using laboratory surveillance data from 2016, 997 serum samples were randomly selected from suspected dengue (DENV) case reports across the Philippines and assayed for serological markers of short-term (IgM) and long-term (IgG) ZIKV exposure. Using mixture models, we re-evaluated ZIKV IgM/G seroprevalence thresholds and used catalytic models to quantify the force of infection (attack rate, AR) from age-accumulated ZIKV exposure. While we observed extensive ZIKV/DENV IgG cross-reactivity, not all individuals with active DENV presented with elevated ZIKV IgG, and a proportion of dengue-negative cases (DENV IgG-) were ZIKV IgG-positive (14.3%, 9/63). We identified evidence of long-term, yet not short-term, ZIKV exposure across Philippine regions (ZIKV IgG+: 31.5%, 314/997) which was geographically uncorrelated with DENV exposure. In contrast to the DENV AR (12.7% (95%CI: 9.1-17.4%)), the ZIKV AR was lower (5.7% (95%CI: 3-11%)) across the country. Our results provide evidence of widespread ZIKV exposure across the Philippines and suggest the need for studies to identify ZIKV infection risk factors over time to better prepare for potential future outbreaks.

Zika Virus

Flavivirus

Seroprevalence

Immunoglobulin M

10.3390/v13081441

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Citations (6)