scholarly journals The Seasonal Dynamics and Biting Behavior of Potential Anopheles Vectors of Plasmodium Knowlesi in Palawan, Philippines

2021 ◽  
Author(s):  
Richard Paul Malijan ◽  
Frank Mechan ◽  
Jessie C Braganza ◽  
Kristelle Mae R. Valle ◽  
Ferdinand V. Salazar ◽  
...  
Keyword(s):  
Plasmodium Knowlesi ◽  
Evaluation Study ◽  
Forest Edge ◽  
The Philippines ◽  
Agricultural Area ◽  
Insecticide Treated Nets ◽  
Human Landing ◽  
Anopheles Vectors ◽  
Palawan Island ◽  
Biting Behavior

Abstract Background: A small number of human cases of the zoonotic malaria Plasmodium knowlesi have been reported in Palawan Island, the Philippines. Identification of potential vector species and their bionomics is crucial for understanding of human exposure risk in this setting. Here, we combined longitudinal surveillance with a trap-evaluation study to address knowledge gaps about the ecology and potential for zoonotic spillover of this macaque malaria in Palawan Island.Methods: The abundance, diversity and biting behavior of human-biting Anopheles mosquitoes were assessed through monthly outdoor Human Landing Catches (HLC) in three ecotypes representing different land use (forest-edge, forest and agricultural area) across 8 months. Additionally, the host preference and biting activity of potential Anopheles vectors was assessed through comparison of their abundance and capture time in traps baited with humans (HLC, human-baited electrocuting net – HEN) or macaques (monkey-baited trap – MBT, monkey-baited electrocuting net – HEN). All female Anopheles mosquitoes were tested for presence of Plasmodium parasite by PCR.Results: Previously incriminated vectors Anopheles balabacensis and An. flavirostris accounted for >95% of Anophelines caught in longitudinal surveillance. However human biting densities were relatively low (An. balabacensis: 0.34 -1.20 per night, An. flavirostris: 0-2 bites per night). Biting densities of An. balabacensis were highest in the forest-edge while An. flavirostris was most abundant in the agricultural area. The abundance of An. balabacensis and An. flavirostris was significantly higher in HLC than MBT. None of the 357 female Anopheles mosquitoes tested for Plasmodium infection were positive.Conclusions: The relatively low density and lack of malaria infection in Anopheles mosquitoes sampled here indicates that exposure to P. knowlesi in this setting is considerably lower than neighbouring countries (Malaysia) where it is now the primary cause of malaria in humans. Although Anophelines had lower abundance in MBT than HLC, An. balabacensis and An. flavirostris were caught by both methods suggesting they could act as bridge vectors between humans and macaques. These species bite primarily outdoors and in early evening; confirming that Insecticide Treated Nets are unlikely to provide protection against P. knowlesi vectors.

scholarly journals The seasonal dynamics and biting behavior of potential Anopheles vectors of Plasmodium knowlesi in Palawan, Philippines

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Richard Paul B. Malijan ◽  
Frank Mechan ◽  
Jessie C. Braganza ◽  
Kristelle Mae R. Valle ◽  
Ferdinand V. Salazar ◽  
...  
Keyword(s):  
Plasmodium Knowlesi ◽  
Evaluation Study ◽  
Forest Edge ◽  
The Philippines ◽  
Agricultural Area ◽  
Insecticide Treated Nets ◽  
Human Landing ◽  
Anopheles Vectors ◽  
Palawan Island ◽  
Biting Behavior

Abstract Background A small number of human cases of the zoonotic malaria Plasmodium knowlesi have been reported in Palawan Island, the Philippines. Identification of potential vector species and their bionomics is crucial for understanding human exposure risk in this setting. Here, we combined longitudinal surveillance with a trap-evaluation study to address knowledge gaps about the ecology and potential for zoonotic spillover of this macaque malaria in Palawan Island. Methods The abundance, diversity and biting behavior of human-biting Anopheles mosquitoes were assessed through monthly outdoor human landing catches (HLC) in three ecotypes representing different land use (forest edge, forest and agricultural area) across 8 months. Additionally, the host preference and biting activity of potential Anopheles vectors were assessed through comparison of their abundance and capture time in traps baited with humans (HLC, human-baited electrocuting net—HEN) or macaques (monkey-baited trap—MBT, monkey-baited electrocuting net—MEN). All female Anopheles mosquitoes were tested for the presence of Plasmodium parasites by PCR. Results Previously incriminated vectors Anopheles balabacensis and An. flavirostris accounted for > 95% of anophelines caught in longitudinal surveillance. However, human biting densities were relatively low (An. balabacensis: 0.34–1.20 per night, An. flavirostris: 0–2 bites per night). Biting densities of An. balabacensis were highest in the forest edge, while An. flavirostris was most abundant in the agricultural area. The abundance of An. balabacensis and An. flavirostris was significantly higher in HLC than in MBT. None of the 357 female Anopheles mosquitoes tested for Plasmodium infection were positive. Conclusions The relatively low density and lack of malaria infection in Anopheles mosquitoes sampled here indicates that exposure to P. knowlesi in this setting is considerably lower than in neighboring countries (i.e. Malaysia), where it is now the primary cause of malaria in humans. Although anophelines had lower abundance in MBTs than in HLCs, An. balabacensis and An. flavirostris were caught by both methods, suggesting they could act as bridge vectors between humans and macaques. These species bite primarily outdoors during the early evening, confirming that insecticide-treated nets are unlikely to provide protection against P. knowlesi vectors. Graphical abstract

Some Dilemmas of Political Consumerism

2018 ◽  
pp. 720-740
Author(s):  
Sarah Webb ◽  
Anna Cristina Pertierra
Keyword(s):  
Middle Class ◽  
Environmentally Friendly ◽  
The Philippines ◽  
Rural Poor ◽  
Political Consumerism ◽  
Palawan Island ◽  
Class Distinction

In the Philippines, socioeconomic relations that result from deeply uneven market engagements have long made consumption a moral affair. Ecoconscious lifestyles and consumer practices remain largely the domain of elite and middle-class Filipinos, and as such, engagement with sustainable and environmentally friendly consumption may be seen not only as a marker of class distinction but also as a critique of urban and rural poor livelihood practices deemed to be environmentally detrimental. Focusing on a case study from Palawan Island, the chapter discusses some dilemmas that have arisen as the application of “eco” to tourism practices has become widespread and attractive to middle-class Filipinos with steadily growing spending power. The relevance of class to considering dilemmas of political consumerism is not unique to the Philippines, and these issues provide an opportunity to critically reflect on who benefits from political consumerism.

scholarly journals LAMA HIDUP DAN POTENSI Culex quinquefasciatus SEBAGAI VEKTOR FILARIASIS LIMFATIK BERDASARKAN KETINGGIAN PASCA TRANSMISSION ASSESMENT SURVEY (TAS) DI KABUPATEN SUBANG, JAWA BARAT

2020 ◽  
Vol 12 (2) ◽  
pp. 155-166
Author(s):  
Endang Puji Astuti ◽  
Mutiara Widawati ◽  
Yuneu Yuliasih ◽  
Andri Ruliansyah ◽  
Asep Jajang Kusnandar
Keyword(s):  
Lymphatic Filariasis ◽  
Mosquito Species ◽  
Evaluation Study ◽  
P Value ◽  
Mosquito Abundance ◽  
Biting Rate ◽  
Human Landing ◽  
The Relationship ◽  
Density Behavior ◽  
Entomological Data

The study on the bioecology of Lymphatic Filariasis (LF) vector is necessary to be used as a support to eliminate LF due to the lack of entomological data for LF vector in Subang, especially after the Provision of Mass Drug Administration for Filariasis Prevention. This study aims to identify mosquito species, density, behavior, longevity, presence of the filaria worm in mosquitoes, and to identify the distribution of mosquitoes in the highlands and lowlands in selected villages in Subang district. This study is part of Lymphatic filariasis (multicenter) evaluation study in Indonesia. The data was collected by using human landing collection method and vector habitat survey data. The entomological data analyzed from the calculation of Man hour density (MHD), Man biting rate (MBR), and longevity, while the relationship between variables and mosquito abundance using Pearson's correlation. The results indicated that the density of mosquitoes caught in Rancahilir was higher than Curug rendeng villages, these results are similar to the LF vector suspect mosquito (Cx. quinquefasciatus). These mosquitoes are found outdoor with peak densities at 22.00-23.00 West Indonesia Time. Altitude has an association with the density of mosquitoes (p-value 0.039). The longevity of Cx. quinquefasciatus population is 10-13 days. At that longevity, vectors are at risk for infective filarial worms. The result shows that Cx. quinquefasciatus collected in this study was negative for filarial worms. Based on the results of this study, we conclude that in Subang, filariasis transmission chain prevention has been successful. However, periodic evaluations is still need to be carried out in order to prevent re-infection of the disease. Abstrak Kajian tentang bioekologi nyamuk vektor Lymphatic Filariasis (LF) di Kabupatem Subang perlu dilakukan. Kajian ini sebagai pendukung untuk menuju eliminasi LF mengingat belum optimalnya data entomologi nyamuk vektor di Subang, terutama pasca Pemberian Obat Masal Pencegahan (POMP) filariasis. Penelitian ini bertujuan mengidentifikasi spesies, kepadatan, perilaku, umur panjang (longevity) populasi nyamuk, identifikasi keberadaan cacing filaria pada nyamuk vektor LF serta menganalisis perbedaan distribusi nyamuk pada dataran tinggi dan rendah di desa terpilih di Kabupaten Subang. Penelitian ini merupakan analisis lanjut dari penelitian “Studi evaluasi filariasis (multicenter) di Indonesia” yang dilaksanakan di beberapa kabupaten di Indonesia.  Data yang diambil, yaitu data survei vektor yang menggunakan metode Human Landing Collection (HLC) dan survei habitat vektor. Analisa data entomologi menggunakan perhitungan Man hour density (MHD), Man-biting rate (MBR) dan  nilai umur panjang nyamuk (longevity), sedangkan hubungan antar variabel dengan kepadatan menggunakan korelasi pearson. Hasil penelitian menunjukkan bahwa kepadatan nyamuk yang tertangkap di Desa Rancahilir (dataran rendah) lebih banyak dibandingkan di Desa Curug rendeng (dataran tinggi), termasuk kepadatan nyamuk Cx. quinquefasciatus yang juga dominan di wilayah ini. Nyamuk ini banyak ditemukan di luar rumah dengan puncak kepadatan pada jam 22.00-23.00 WIB. Ketinggian mempunyai hubungan dengan kepadatan nyamuk tertangkap (p value 0,039). Umur populasi nyamuk Cx. quinquefasciatus 10-13 hari. Umur ini menunjukkan umur populasi yang berisiko untuk infektif cacing filaria. Hasil pemeriksaan nyamuk Cx. quinquefasciatus negatif terhadap cacing filarial. Hasil ini menunjukkan bahwa di Kabupaten Subang telah berhasil memutuskan rantai penularan filaria. Namun, masih perlu dilaksanakan evaluasi berkala agar tidak terjadi penularan kembali di wilayah ini.

REDD Policy Impacts on Indigenous Property Rights Regimes on Palawan Island, the Philippines

Human Ecology ◽  
2012 ◽  
Vol 40 (5) ◽  
pp. 679-691 ◽  
Author(s):  
Wolfram Dressler ◽  
Melanie McDermott ◽  
Will Smith ◽  
Juan Pulhin
Keyword(s):  
Property Rights ◽  
The Philippines ◽  
Policy Impacts ◽  
Palawan Island ◽  
Indigenous Property Rights

scholarly journals Exposure and infection to Plasmodium knowlesi in case study communities in Northern Sabah, Malaysia and Palawan, The Philippines

2018 ◽  
Vol 12 (6) ◽  
pp. e0006432 ◽  
Author(s):  
Kimberly M. Fornace ◽  
Lou S. Herman ◽  
Tommy R. Abidin ◽  
Tock Hing Chua ◽  
Sylvia Daim ◽  
...  
Keyword(s):  
Plasmodium Knowlesi ◽  
The Philippines

Biting Behavior and Molecular Identification of Aedes aegypti (Diptera: Culicidae) Subspecies in Some Selected Recent Yellow Fever Outbreak Communities in Northern Ghana

2020 ◽  
Vol 57 (4) ◽  
pp. 1239-1245
Author(s):  
Millicent Captain-Esoah ◽  
Philip Kweku Baidoo ◽  
Kwadwo K Frempong ◽  
Delphina Adabie-Gomez ◽  
Joseph Chabi ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Yellow Fever ◽  
Close Association ◽  
Random Amplified Polymorphic Dna ◽  
Northern Ghana ◽  
Human Populations ◽  
Molecular Technique ◽  
Control Programs ◽  
Human Landing ◽  
Biting Behavior

Abstract Aedes aegypti (L.) (Diptera: Culicidae) is a diurnal feeder that lives in close association with human populations. It is the principal vector of yellow fever, dengue fever and the Zika Virus. Issues of arboviral diseases have been on the ascendency in most countries including Ghana where Aedes mosquito is the main vector of yellow fever. A comparative study of the biting behavior of Ae. aegypti and the identification of subspecies were undertaken using molecular technique. Standard human landing technique was used to collect both indoor and outdoor biting mosquitoes at three zones located in the Upper East (Bolgatanga), Upper West (Nadowli), and Northern (Damongo) Regions of Ghana during the dry and rainy seasons between 0600 and 1800 Greenwich Mean Time (GMT). All collected mosquitoes were identified morphologically using taxonomic keys. random amplified polymorphic DNA polymerase chain reaction was used to categorize Ae. aegypti into subspecies. Adult female Aedes mosquitoes identified formed 62% (n = 1,206) of all female mosquitoes collected. Aedes aegypti 98% and Aedes vittatus 2% were the only Aedes species identified. Bolgatanga recorded the largest number of Ae. aegypti 42%, whereas Nadowli 22% recorded the least. Aedes vittatus was observed in Nadowli. Aedes aegypti exhibited a bimodal biting behavior peaking at 0600–0800 GMT and 1500–1600 h GMT. Molecular findings revealed 69% Ae. aegypti aegypti and 31% Ae. aegypti formosus as the two subspecies (n = 110). This information is important for implementing effective vector control programs in the three regions of the northern Ghana.

Allelic diversity in the merozoite surface protein 1 gene of Plasmodium falciparum on Palawan Island, the Philippines

2007 ◽  
Vol 56 (3) ◽  
pp. 185-194 ◽  
Author(s):  
Naoko Sakihama ◽  
Masatoshi Nakamura ◽  
Antonio A. Palanca ◽  
Renee A. Argubano ◽  
Ester P. Realon ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Allelic Diversity ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
The Philippines ◽  
Merozoite Surface Protein 1 ◽  
Palawan Island

scholarly journals Population genomic structure and adaptation in the zoonotic malaria parasite Plasmodium knowlesi

2015 ◽  
Vol 112 (42) ◽  
pp. 13027-13032 ◽  
Author(s):  
Samuel Assefa ◽  
Caeul Lim ◽  
Mark D. Preston ◽  
Craig W. Duffy ◽  
Mridul B. Nair ◽  
...  
Keyword(s):  
Malaria Parasite ◽  
Plasmodium Knowlesi ◽  
Balancing Selection ◽  
Rhesus Macaques ◽  
Genomic Structure ◽  
The Philippines ◽  
Peninsular Malaysia ◽  
Clinical Isolates ◽  
Fixation Index ◽  
Tajima’S D

Malaria cases caused by the zoonotic parasite Plasmodium knowlesi are being increasingly reported throughout Southeast Asia and in travelers returning from the region. To test for evidence of signatures of selection or unusual population structure in this parasite, we surveyed genome sequence diversity in 48 clinical isolates recently sampled from Malaysian Borneo and in five lines maintained in laboratory rhesus macaques after isolation in the 1960s from Peninsular Malaysia and the Philippines. Overall genomewide nucleotide diversity (π = 6.03 × 10−3) was much higher than has been seen in worldwide samples of either of the major endemic malaria parasite species Plasmodium falciparum and Plasmodium vivax. A remarkable substructure is revealed within P. knowlesi, consisting of two major sympatric clusters of the clinical isolates and a third cluster comprising the laboratory isolates. There was deep differentiation between the two clusters of clinical isolates [mean genomewide fixation index (FST) = 0.21, with 9,293 SNPs having fixed differences of FST = 1.0]. This differentiation showed marked heterogeneity across the genome, with mean FST values of different chromosomes ranging from 0.08 to 0.34 and with further significant variation across regions within several chromosomes. Analysis of the largest cluster (cluster 1, 38 isolates) indicated long-term population growth, with negatively skewed allele frequency distributions (genomewide average Tajima’s D = −1.35). Against this background there was evidence of balancing selection on particular genes, including the circumsporozoite protein (csp) gene, which had the top Tajima’s D value (1.57), and scans of haplotype homozygosity implicate several genomic regions as being under recent positive selection.

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