scholarly journals Comparison of Climatic Factors on Mosquito Abundance at US Army Garrison Humphreys, Republic of Korea

2020 ◽  
Author(s):  
Myung-Jae Hwang ◽  
Heung-Chul Kim ◽  
Terry A. Klein ◽  
Sung-Tae Chong ◽  
Kisung Sim ◽  
...  

Abstract Background A number of studies have been conducted on the relationship between the distribution of mosquito abundance and meteorological variables. However, few studies have specifically provided specific ranges of temperatures for estimating the maximum abundance of mosquitoes as an empirical basis for climatic dynamics for estimating mosquito-borne infectious disease risks.Methods Adult mosquitoes were collected for three consecutive nights/week using Mosquito Magnet® Independence® model traps during 2018 and 2019 at US Army Garrison (USAG) Humphreys, Pyeongtaek, Gyeonggi Province, Republic of Korea (ROK). An estimate of daily mean temperatures (provided by the Korea Meteorological Administration) were distributed at the maximum abundance for selected species of mosquitoes using daily mosquito collection data after controlling for mosquito ecological cycles and environmental factors.Results Using the Monte-Carlo simulation, the overall mosquito population abundance peaked at 22.7℃ (2.5th−-97.5th : 21.7℃–23.8 ℃). Aedes albopictus, vector of Zika, chikungunya, dengue fever and other viruses, abundance peaked at 24.6℃ (2.5th − 97.5th, 22.3℃–25.6℃), while Japanese encephalitis virus (JEV) vectors, e.g., Culex tritaeniorhynchus and Culex pipiens, peaked at 24.3℃ (2.5th − 97.5th : 21.9℃–26.3℃) and 22.6℃ (2.5th − 97.5th : 21.9℃–25.2℃), respectively. Members of the Anopheles Hyrcanus Group, some of which are vivax malaria vectors in the ROK, abundance peaked at 22.4℃ (2.5th − 97.5th : 21.5℃–23.8℃).Conclusion The empirical mean temperature ranges for maximum abundance were determined for each mosquito species collected at USAG Humphreys. These data contributed to the identification of relative mosquito abundance patterns for estimating mosquito-borne disease risks and developing and implementing disease prevention practices.

PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0240363
Author(s):  
Myung-Jae Hwang ◽  
Heung-Chul Kim ◽  
Terry A. Klein ◽  
Sung-Tae Chong ◽  
Kisung Sim ◽  
...  

2020 ◽  
Author(s):  
Assalif Demissew Shifera ◽  
Dawit Hawaria ◽  
Solomon Kibret ◽  
Abebe Animut ◽  
Arega Tsegaye ◽  
...  

Abstract Background: Although irrigation activities are increasing in Ethiopia, limited studies evaluated their impact on malaria vector mosquito composition, abundance and seasonality. This study aimed at evaluating the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods : Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquito collections were conducted in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were identified to species using morphological keys and An. gambiae s.l to sibling species using PCR. Chi-square was used to analyze the association between Anopheles species occurrence and environmental and seasonal parameters. Results: Overall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. An. gambiae s.l was the most abundant (67.3%) followed by An. coustani complex (25.3 %) and An. pharoensis (5.7%). PCR based identification revealed that 74.7% (n=168) of the An. gambiae s.l were An. arabiensis and 22.7% (n=51) An. amharicus . Density of An. gambiae s.l. (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1837) was higher than the dry seasons (12.8%; n=271). Conclusion : The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for increased malaria transmitting Anopheles species diversity and abundance. This in turn could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Thus, currently practiced malaria vector interventions need to be strengthened and consider larval source management to reduce vector abundance in the irrigated areas. Key Words: Malaria, Irrigation, Anopheles mosquitoes, vector density, An. amharicus , Ethiopia


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Assalif Demissew ◽  
Dawit Hawaria ◽  
Solomon Kibret ◽  
Abebe Animut ◽  
Arega Tsegaye ◽  
...  

Abstract Background Despite extensive irrigation development in Ethiopia, limited studies assessed the impact of irrigation on malaria vector mosquito composition, abundance and seasonality. This study aimed to evaluate the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquitoes were surveyed in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were sorted out to species using morphological keys and molecular techniques. Chi square was used to test the relationships between Anopheles species occurrence, and environmental and seasonal parameters. Results Overall, 2108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n = 1954) were from irrigated clusters and 7.3% (n = 154) from the non-irrigated. The Anopheles gambiae complex was the most abundant (67.3%) followed by Anopheles coustani complex (25.3%) and Anopheles pharoensis (5.7%). PCR-based identification revealed that 74.7% (n = 168) of the An. gambiae complex were Anopheles arabiensis and 22.7% (n = 51) Anopheles amharicus. The density of An. gambiae complex (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n = 1837) was higher than the dry seasons (12.8%; n = 271). Conclusion The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for malaria transmitting Anopheles species diversity and abundance. This could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Currently practiced malaria vector interventions need to be strengthened by including larval source management to reduce vector abundance in the irrigated areas.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bram van de Straat ◽  
Tanya L. Russell ◽  
Kyran M. Staunton ◽  
Marianne E. Sinka ◽  
Thomas R. Burkot

AbstractThe epidemiology of human malaria differs considerably between and within geographic regions due, in part, to variability in mosquito species behaviours. Recently, the WHO emphasised stratifying interventions using local surveillance data to reduce malaria. The usefulness of vector surveillance is entirely dependent on the biases inherent in the sampling methods deployed to monitor mosquito populations. To understand and interpret mosquito surveillance data, the frequency of use of malaria vector collection methods was analysed from a georeferenced vector dataset (> 10,000 data records), extracted from 875 manuscripts across Africa, the Americas and the Asia-Pacific region. Commonly deployed mosquito collection methods tend to target anticipated vector behaviours in a region to maximise sample size (and by default, ignoring other behaviours). Mosquito collection methods targeting both host-seeking and resting behaviours were seldomly deployed concurrently at the same site. A balanced sampling design using multiple methods would improve the understanding of the range of vector behaviours, leading to improved surveillance and more effective vector control.


2020 ◽  
Author(s):  
Assalif Demissew Shifera ◽  
Dawit Hawaria ◽  
Solomon Kibret ◽  
Abebe Animut ◽  
Arega Tsegaye ◽  
...  

Abstract Background: Despite extensive irrigation development in Ethiopia, limited studies assessed the impact of irrigation on malaria vector mosquito composition, abundance and seasonality. This study aimed at evaluating the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods: Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquitoes were surveyed in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were sorted out to species using morphological keys and molecular techniques. Chi-square was used to test the relationships between Anopheles species occurrence, and environmental and seasonal parameters. Results: Overall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. An. gambiae s.l was the most abundant (67.3%) followed by An. coustani complex (25.3 %) and An. pharoensis (5.7%). PCR based identification revealed that 74.7% (n=168) of the An. gambiae s.l were An. arabiensis and 22.7% (n=51) An. amharicus. Density of An. gambiae s.l. (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1837) was higher than the dry seasons (12.8%; n=271).Conclusion: The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for malaria transmitting Anopheles species diversity and abundance. This could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Thus, currently practiced malaria vector interventions need to be strengthened by including larval source management to reduce vector abundance in the irrigated areas.


2020 ◽  
Author(s):  
Assalif Demissew Shifera ◽  
Dawit Hawaria ◽  
Solomon Kibret ◽  
Abebe Animut ◽  
Arega Tsegaye ◽  
...  

Abstract Background: Although irrigation activities are increasing in Ethiopia, limited studies evaluated their impact on malaria vector mosquito composition, abundance and seasonality. This study aimed at evaluating the impact of sugarcane irrigation on species composition, abundance and seasonality of malaria vectors. Methods: Adult Anopheles mosquitoes were collected using CDC light traps from three irrigated and three non-irrigated clusters in and around Arjo-Didessa sugarcane irrigation scheme in southwestern Ethiopia. Mosquito collections were conducted in four seasons: two wet and two dry, in 2018 and 2019. Mosquito species composition, abundance and seasonality were compared between irrigated and non-irrigated clusters. Anopheles mosquitoes were identified to species using morphological keys and An. gambiae s.l to sibling species using PCR. Chi-square was used to analyze the association between Anopheles species occurrence and environmental and seasonal parameters. Results: Overall, 2,108 female Anopheles mosquitoes comprising of six species were collected. Of these, 92.7% (n=1954) were from irrigated clusters and 7.3% (n=154) from the non-irrigated. An. gambiae s.l was the most abundant (67.3%) followed by An. coustani complex (25.3 %) and An. pharoensis (5.7%). PCR based identification revealed that 74.7% (n=168) of the An. gambiae s.l were An. arabiensis and 22.7% (n=51) An. amharicus. Density of An. gambiae s.l. (both indoor and outdoor) was higher in irrigated than non-irrigated clusters. The overall anopheline mosquito abundance during the wet seasons (87.2%; n=1837) was higher than the dry seasons (12.8%; n=271). Conclusion: The ongoing sugarcane irrigation activities in Arjo-Didessa created conditions suitable for increased malaria transmitting Anopheles species diversity and abundance. This in turn could drive malaria transmission in Arjo-Didessa and its environs in both dry and wet seasons. Thus, currently practiced malaria vector interventions need to be strengthened and consider larval source management to reduce vector abundance in the irrigated areas.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Bianca E Silva ◽  
Zvifadzo Matsena Zingoni ◽  
Lizette L. Koekemoer ◽  
Yael L. Dahan-Moss

Abstract Background Mosquito species from the Anopheles gambiae complex and the Anopheles funestus group are dominant African malaria vectors. Mosquito microbiota play vital roles in physiology and vector competence. Recent research has focused on investigating the mosquito microbiota, especially in wild populations. Wild mosquitoes are preserved and transported to a laboratory for analyses. Thus far, microbial characterization post-preservation has been investigated in only Aedes vexans and Culex pipiens. Investigating the efficacy of cost-effective preservatives has also been limited to AllProtect reagent, ethanol and nucleic acid preservation buffer. This study characterized the microbiota of African Anopheles vectors: Anopheles arabiensis (member of the An. gambiae complex) and An. funestus (member of the An. funestus group), preserved on silica desiccant and RNAlater® solution. Methods Microbial composition and diversity were characterized using culture-dependent (midgut dissections, culturomics, MALDI-TOF MS) and culture-independent techniques (abdominal dissections, DNA extraction, next-generation sequencing) from laboratory (colonized) and field-collected mosquitoes. Colonized mosquitoes were either fresh (non-preserved) or preserved for 4 and 12 weeks on silica or in RNAlater®. Microbiota were also characterized from field-collected An. arabiensis preserved on silica for 8, 12 and 16 weeks. Results Elizabethkingia anophelis and Serratia oryzae were common between both vector species, while Enterobacter cloacae and Staphylococcus epidermidis were specific to females and males, respectively. Microbial diversity was not influenced by sex, condition (fresh or preserved), preservative, or preservation time-period; however, the type of bacterial identification technique affected all microbial diversity indices. Conclusions This study broadly characterized the microbiota of An. arabiensis and An. funestus. Silica- and RNAlater®-preservation were appropriate when paired with culture-dependent and culture-independent techniques, respectively. These results broaden the selection of cost-effective methods available for handling vector samples for downstream microbial analyses.


Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 878
Author(s):  
Chang-Hyun Park ◽  
Ui-Cheon Lee ◽  
Soo-Chul Kim ◽  
Kwang-Hee Lee

To analyze the relationship between climatic factors (monthly mean temperature and total precipitation) and tree-ring growths of Pinus densiflora from the central region of the Republic of Korea, more than 20 trees were sampled from three national parks. The tree-ring chronology of Mt. Bukhan covering the period of 1917–2016 was assessed, as well as that of Mt. Seorak across 1687–2017 and Mt. Worak across 1777–2017. After cross-dating, each ring-width series was double-standardized by first fitting a logarithmic curve and then a 50 year cubic spline. Climate-growth relationships were computed with bootstrap correlation functions. The result of the analysis showed a positive response from the current March temperature and May precipitations for tree-ring growth of Pinus densiflora. It indicates that a higher temperature supply during early spring season and precipitation during cambium activity are important for radial growths of Pinus densiflora from the central region in the Republic of Korea.


2020 ◽  
Author(s):  
Triwibowo Ambar Garjito ◽  
Lulus Susanti ◽  
Mujiyono Mujiyono ◽  
Mega Tyas Prihatin ◽  
Dwi Susilo ◽  
...  

Abstract BackgroundSeveral methods exist to collect and assess the abundance of dengue vector mosquitoes, i.e. morning adult collection using an aspirator, pupal collection, various ovitraps, whole night collection using human landing methods, and larval collection. This diversity of methods might be a source of variability and lack of statistical significance when trying to correlate mosquito density and risk of dengue outbreak. There is also a lack of published data regarding the effectiveness of these methods MethodsA mosquito survey was conducted in 39 locations corresponding to 15 dengue endemic provinces in Indonesia. The larval surveys were performed by collecting at least a single Aedes larva from each container, and then reared up until hatching. Three adult mosquito sampling methods were also used, including morning resting collection, human landing collection, animal baited trap. All field samples were tested for dengue. Factor Analysis of Mixed Data (FAMD) was conducted to analyze the effectiveness of the collection methods against mosquito species and dengue incidence.ResultsA total of 44,675 mosquitoes were collected. The single larva method was the most efficient method. Out of a total of 89 dengue-positive pools, the most frequently encountered virus was DENV2, which made up half of the positive samples, followed by DENV3 and DENV1, respectively. FAMD showed that no correlation could be found between any methods and the presence of dengue virus in mosquitoes. Moreover, no correlation could be found between either any methods or the incidence.ConclusionsThere was no concistency in the efficacy of a given method and the incidence of dengue in the human population. There was no correlation between any of the parameters considered, i.e. method, incidence of dengue, location and presence of dengue virus in mosquitoes. This indicates that entomological factors are not reliable indicators.


2020 ◽  
Vol 12 (2) ◽  
pp. 155-166
Author(s):  
Endang Puji Astuti ◽  
Mutiara Widawati ◽  
Yuneu Yuliasih ◽  
Andri Ruliansyah ◽  
Asep Jajang Kusnandar

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.


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