The University of The Philippines Mindanao

The family Heterophyidae includes endoparasitic minute intestinal flukes that are primarily transmitted through the consumption of raw or undercooked fish, causing heterophyidiasis. Several heterophyid species have been reported to infect humans in the Philippines. Heterophyidiasis is diagnosed by detection of parasite ova in stool samples through Kato-Katz stool microscopy, but species identification is challenging due to the morphologically similar eggs of different heterophyid species and other minute intestinal flukes such as Clonorchis and Opisthorchis. This study addresses the need for accurate species identification by employing molecular techniques, specifically nested PCR and DNA sequencing of the 5.8S-ITS2 rDNA region, to identify heterophyid eggs in human stool samples in the Philippines. This study detected 10 human stool samples infected with Haplorchis taichui from Leyte and Davao del Norte, with all ten sequences clustering with H. taichui sequences from Vietnam. One sample contained Opisthorchis viverrini, an opisthorchiid that is nested inside Heterophyidae. The study also identified two novel genotypes of Haplorchis sp. These results contribute to our knowledge of the diversity of medically important trematodes in the Philippines and emphasize the usefulness of molecular techniques for the accurate identification of heterophyid parasite eggs.

Shellac is an enteric material with potential to deliver probiotics to the colon. This study explored shellac-based microgels to entrap Lactobacillus bulgaricus ATCC 11842, a probiotic strain used in the food industry but undetectable after simulated digestion. Dispersions with one, two, or all of shellac (5.0 % w/v), zein (2.0 % w/v), and sodium alginate (1.0 % w/v) were prepared at pH 7.7, mixed with probiotics, and sprayed to 2.5 % w/v calcium chloride at pH 3.0, 4.5, or 6.0 to form microgels. Wet microcapsules were collected by centrifugation and characterized for size, microstructure, FTIR spectra, and cell viability during simulated digestion and storage. Irregularly shaped microcapsules had a volume-weighted mean diameter of 84-354 μm. FTIR spectra revealed hydrogen bonding, electrostatic, and hydrophobic interactions in microcapsule formation. Similar viable cell density (7.08-9.40 log CFU/g) but different mass yield was obtained, with entrapment efficiencies of 42.1-112.6 % at pH 3.0, 46.2-95.3 % at pH 4.5, and 45.6-97.6 % at pH 6.0. The reduction was below 2 log CFU/g during 21-day storage at 4 °C and pH 4.5. However, only shellac-zein, shellac-zein-alginate, and shellac-alginate microcapsules fabricated at pH 4.5 had at least 5 log CFU/g viable cells after simulated digestion. This work supports shellac-based probiotic delivery in functional foods.

Camera traps are powerful tools that facilitate ecological monitoring and behavioral observations of non-human primates. Although supposedly non-intrusive, some models generate sound and illumination that elicit behavioral responses from different species. Reactions of primates to camera traps are poorly documented, including those of tarsiers, despite their distinctive auditory and visual specializations. Here, we described the reactions of wild Philippine tarsiers (Carlito syrichta) to camera traps based on existing video records on Leyte Island (N = 12) and characterized the light and sound emissions of the camera traps used for recording. We observed avoidance, attraction, and inspection behaviors from the tarsiers after their looking impulses. Using a spectrometer and ultrasonic acoustic analysis, we found that the camera traps emitted light at predominantly infrared wavelengths with peaks at ca. 850 nm (low glow) and ca. 930 nm (no glow). Some low-glow models produced a faint red glow during recording and a detectable clicking sound upon trigger, whereas the no-glow camera traps emitted infrared light with significant ultraviolet components. Based on spectral sensitivity approximations and audible threshold assessments, we found that the emissions of the camera traps are detectable, not only to tarsiers but also other primate species. Our findings suggest that camera traps influence the behavior of tarsiers. Hence, we advise caution when using camera traps since behavioral reactions may induce bias depending on the framing of studies. We also recommend proper planning when accounting for these behaviors, selecting camera trap models, and designing camera trapping studies.