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Manalo DL, Bolivar JKG, Yap PR, Gomez MRR, Saldo ZP, Espino MJM, Dilig JE, Fornillos RJC, Perez SA, Baga RA, Sunico LS, Fontanilla IKC, Leonardo LR. From Perpetual Wetness to Soil Chemistry: Enumerating Environmental and Physicochemical Factors Favoring Oncomelania hupensis quadrasi Snail Presence in the Municipality of Gonzaga, Cagayan, Philippines. Trop Med Infect Dis 2023; 9:9. [PMID: 38251207 PMCID: PMC10819408 DOI: 10.3390/tropicalmed9010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 12/02/2023] [Accepted: 12/03/2023] [Indexed: 01/23/2024] Open
Abstract
Snail control to complement mass drug administration is being promoted by the World Health Organization for schistosomiasis control. Oncomelania hupensis quadrasi, the snail intermediate host of Schistosoma japonicum in the Philippines, has a very focal distribution; thus, scrutinizing baseline data and parameters affecting this distribution is very crucial. In this study in Gonzaga, Cagayan, Philippines, snail habitats were surveyed, and the various factors affecting the existence of the snails were determined. Malacological surveys and the mapping of sites of perpetual wetness in five endemic and five neighboring non-endemic barangays were conducted. Environmental and physicochemical factors were also examined. Maps of both snail and non-snail sites were generated. Of the fifty sites surveyed, O. h. quadrasi were found in twelve sites, and two sites yielded snails that were infected with S. japonicum cercariae. Factors such as silty loam soil, proximity to a snail site, water ammonia, and soil attributes (organic matter, iron, and pH) are all significantly associated with the presence of snails. In contrast, types of habitats, temperatures, and soil aggregation have no established association with the existence of snails. Mapping snail sites and determining factors favoring snail presence are vital to eliminating snails. These approaches will significantly maximize control impact and minimize wasted efforts and resources, especially in resource-limited schistosomiasis endemic areas.
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Affiliation(s)
- Daria L. Manalo
- Department of Health, Research Institute for Tropical Medicine, 9002 Research Drive, Filinvest Corporate City, Alabang, Muntinlupa 1781, Philippines; (J.K.G.B.); (P.R.Y.); (M.R.R.G.)
- Institute of Biology, University of the Philippines Diliman, Quezon 1101, Philippines (I.K.C.F.); (L.R.L.)
| | - Jude Karlo G. Bolivar
- Department of Health, Research Institute for Tropical Medicine, 9002 Research Drive, Filinvest Corporate City, Alabang, Muntinlupa 1781, Philippines; (J.K.G.B.); (P.R.Y.); (M.R.R.G.)
- Department of Science and Technology, Science Education Institute, Taguig 1631, Philippines
| | - Paul Raymund Yap
- Department of Health, Research Institute for Tropical Medicine, 9002 Research Drive, Filinvest Corporate City, Alabang, Muntinlupa 1781, Philippines; (J.K.G.B.); (P.R.Y.); (M.R.R.G.)
- Department of Science and Technology, Science Education Institute, Taguig 1631, Philippines
| | - Ma. Ricci R. Gomez
- Department of Health, Research Institute for Tropical Medicine, 9002 Research Drive, Filinvest Corporate City, Alabang, Muntinlupa 1781, Philippines; (J.K.G.B.); (P.R.Y.); (M.R.R.G.)
| | - Zaldy P. Saldo
- Department of Health, Research Institute for Tropical Medicine, 9002 Research Drive, Filinvest Corporate City, Alabang, Muntinlupa 1781, Philippines; (J.K.G.B.); (P.R.Y.); (M.R.R.G.)
| | - Mark Joseph M. Espino
- Department of Health, Research Institute for Tropical Medicine, 9002 Research Drive, Filinvest Corporate City, Alabang, Muntinlupa 1781, Philippines; (J.K.G.B.); (P.R.Y.); (M.R.R.G.)
| | - Joselito E. Dilig
- Department of Health, Research Institute for Tropical Medicine, 9002 Research Drive, Filinvest Corporate City, Alabang, Muntinlupa 1781, Philippines; (J.K.G.B.); (P.R.Y.); (M.R.R.G.)
| | - Raffy Jay C. Fornillos
- Institute of Biology, University of the Philippines Diliman, Quezon 1101, Philippines (I.K.C.F.); (L.R.L.)
| | - Shirlyn A. Perez
- Center for Health and Development Region II, Carig Regional Center, Tuguegarao 3500, Philippines
| | - Regie A. Baga
- Center for Health and Development Region II, Carig Regional Center, Tuguegarao 3500, Philippines
| | | | - Ian Kendrich C. Fontanilla
- Institute of Biology, University of the Philippines Diliman, Quezon 1101, Philippines (I.K.C.F.); (L.R.L.)
| | - Lydia R. Leonardo
- Institute of Biology, University of the Philippines Diliman, Quezon 1101, Philippines (I.K.C.F.); (L.R.L.)
- Office of Research Coordination, University of the East, 2219 C.M. Recto Avenue, Brgy. 404, Zone 41, Sampaloc, Manila 1008, Philippines
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Assessing the Orange Tree Crown Volumes Using Google Maps as a Low-Cost Photogrammetric Alternative. AGRONOMY-BASEL 2020. [DOI: 10.3390/agronomy10060893] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The accurate assessment of tree crowns is important for agriculture, for example, to adjust spraying rates, to adjust irrigation rates or even to estimate biomass. Among the available methodologies, there are the traditional methods that estimate with a three-dimensional approximation figure, the HDS (High Definition Survey), or TLS (Terrestrial Laser Scanning) based on LiDAR technology, the aerial photogrammetry that has re-emerged with unmanned aerial vehicles (UAVs), as they are considered low cost. There are situations where either the cost or location does not allow for modern methods and prices such as HDS or the use of UAVs. This study proposes, as an alternative methodology, the evaluation of images extracted from Google Maps (GM) for the calculation of tree crown volume. For this purpose, measurements were taken on orange trees in the south of Spain using the four methods mentioned above to evaluate the suitability, accuracy, and limitations of GM. Using the HDS method as a reference, the photogrammetric method with UAV images has shown an average error of 10%, GM has obtained approximately 50%, while the traditional methods, in our case considering ellipsoids, have obtained 100% error. Therefore, the results with GM are encouraging and open new perspectives for the estimation of tree crown volumes at low cost compared to HDS, and without geographical flight restrictions like those of UAVs.
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