Biology subjects

Masangkay, J. S.

Publications and source records attributed to Masangkay, J. S..

3 recordsLinked to original sources

bioRxiv2026

Detection of Japanese Encephalitis Virus in Mosquitoes Collected from Selected Areas of Laguna, Philippines Using an Optimized One-Step RT-PCR Protocol

Japanese encephalitis virus is a leading cause of encephalitis in humans and agricultural animals across Southern and Eastern Asia. It is primarily transmitted by mosquitoes of the Culex genus, notably Culex tritaeniorhynchus. In the Philippines, JEV is reported to account for 7% to 18% of clinical cases of meningitis and encephalitis. Therefore, updated and comprehensive data on circulating JEV strains in the country are crucial for developing effective mitigation strategies. This study aimed to optimize an assay for JEV detection using one-step reverse transcription polymerase chain reaction (RT-PCR). Additionally, the presence of JEV in mosquitoes collected from eleven cities and municipalities in Laguna was assessed, and the mosquito carriers were identified based on morphological characteristics. Results demonstrated that the optimized one-step RT-PCR assay successfully detected JEV at various dilutions, with a limit of detection (LoD) of 0.115 ng/L. The assay exhibited 100% specificity, with no amplification observed for any viruses other than JEV. Sequence analysis of the positive control, JEV SA14-14-2 RNA, revealed 96.96% to 98.41% similarity to JEV reference sequences in the NCBI database. Among the 5,522 female mosquitoes collected, Culex tritaeniorhynchus and Culex gelidus were the most prevalent species. The highest mosquito species diversity and the most even distribution were found in the three barangays of Paete, but Siniloan, Laguna had the highest vector density for the three Culex species, Culex tritaeniorhynchus, Culex gelidus, and Culex fuscocephala. RT-PCR analysis of 189 pooled mosquito samples revealed no detectable JEV genetic material. This study is likely the first investigation of JEV presence in mosquito samples from Laguna, Philippines. These findings contribute to proactive JEV surveillance, enhancing our understanding of the virus's presence and distribution. The results underscore the importance of targeted prevention and control measures to mitigate JEV transmission in high-risk areas.

molecular biology↗

bioRxiv2025

Genome-wide analysis reveals mutual gene flow between goats from Island Southeast Asia and from Southern Africa

This study aimed to reveal a comprehensive genetic diversity and genetic structure of Island Southeast Asian (ISEA) goats, and infer the details of gene introgressions and propagation routes in ISEA goats using genome-wide SNPs. Correlation analysis of the distance from the domestication center and the genetic diversity of each Asian population showed a significant negative correlation (r = - 0.796, p = 2.66E-05), while the Philippines showed a relatively high genetic diversity (He = 0.363) against the distance, suggesting the multiple propagation routes and admixture history in Philippine goats. Reduced Representation Admixture Analysis at K=6 showed that six clusters (Europe, Northwest Africa, Southern Africa, Eastern Africa, Asia and Southeast Asia) were formed based primarily on geographical location, and ISEA goats included African and Europe components. However, this introgression is much lower in Indochinese goats. In addition, the Southern African and European populations included Southeast Asia component. Treemix and f4 statistics analyses showed the genetic influence and gene flow between ISEA and the Southern Africa. The results of this study have revealed obvious mutual gene flow between ISEA and the Southern African regions through the European maritime activities across the Indian Ocean since the Middle Ages.

ecology↗

bioRxiv2020

Bacteriological and histopathological findings in cetaceansthat stranded in the Philippines from 2017 to 2018

The relatively high frequency of marine mammal stranding events in the Philippines provide many research opportunities. A select set of stranders (n=21) from 2017 to 2018 were sampled for bacteriology and histopathology. Pertinent tissues and bacteria were collected from eight species (i.e. Feresa attenuata, Kogia breviceps, Globicephala macrorhynchus, Grampus griseus, Lagenodelphis hosei, Peponocephala electra, Stenella attenuata and Stenella longirostris) and were subjected to histopathological examination and antibiotic resistance screening, respectively. Lesions that were observed in tissues of 19 cetaceans include congestion, hemorrhage, edema, hemosiderosis, glomerulopathy, Zenkers necrosis, atrophy, atelectasis, and parasitic cysts. These lesions may be associated with factors possibly contributing to the death, debility, and stress of the animals during their strandings. On the other hand, the resistance profiles of 24 bacteria (belonging to genera Escherichia, Enterobacter, Klebsiella, Proteus, and Shigella) that were isolated from four cetaceans were determined using 18 antibiotics. All 24 isolates were resistant to at least one antibiotic class, and 79.17% were classified as multiple antibiotic resistant (MAR). The MAR index values of isolates ranged from 0.06 to 0.39 with all the isolates resistant to erythromycin (100%; n=24) and susceptible to imipenem, doripenem, ciprofloxacin, chloramphenicol, and gentamicin (100%; n=24). The resistance profiles of these bacteria can be used as basis for selecting antibiotics needed in the medical management of stranded cetaceans that need to be rehabilitated. Overall, the histopathological and bacteriological findings of the study demonstrate the challenges faced by cetacean species in the wild, such as but not limited to, biological pollution through land-sea movement of effluents, fisheries interactions, and anthropogenic activities.

zoology↗