Eastern Cambodia Research Articles

Teleconnections of Atmospheric Circulations to Meteorological Drought in the Lancang-Mekong River Basin

The Lancang-Mekong River Basin (LMRB) is one of the major transboundary basins globally, facing ongoing challenges due to flood and drought disasters. Particularly in the past two decades, the basin has experienced an increased frequency of meteorological drought events, posing serious threats to the local socio-economic structures and ecological systems. Thus, this study aimed to analyze the meteorological drought characteristics in the LMRB and identify the impact and correlation of atmospheric circulation on the meteorological drought in the basin. Specifically, the different levels of meteorological drought events were defined using the Run Theory based on the seasonal and annual SPEI from 1980 to 2018. The time lag correlation between meteorological drought events and the EI Nino-Southern Oscillation (ENSO), Arctic Oscillation (AO), North Atlantic Oscillation (NAO), and Pacific Decadal Oscillation (PDO), were analyzed in the LMRB. Our results indicated that, from a temporal perspective, the period from November to April of the following year was particularly prone to meteorological droughts in the basin. In terms of spatial distribution, the primary agricultural regions within the basin, including Thailand, Eastern Cambodia, and Vietnam, were highly susceptible to meteorological droughts. Further analysis revealed a teleconnection between drought events in the LMRB and atmospheric circulation factors. The sensitivity of the basin’s drought timing to its response decreased in the order of the ENSO > AO > NAO > PDO. In general, the ENSO had the most substantial influence on drought events in the basin, with the strongest response relationship, while the upper reaches of the basin displayed the most significant response to the AO; the occurrence and progression of meteorological droughts in this area synchronized with the AO. These findings enhance our understanding of drought-prone areas in the LMRB, including the meteorological factors and driving mechanisms involved. This information is valuable for effectively mitigating and managing drought risks in the region.

Quantifying the availability of seasonal surface water and identifying the drivers of change within tropical forests in Cambodia.

Surface freshwater is a vital resource that is declining globally, predominantly due to climate and land use changes. Cambodia is no exception and the loss threatens many species, such as the giant ibis a Critically Endangered waterbird. We aimed to quantify the spatial and temporal (2000-2020) change of surface water availability across northern and eastern Cambodia and to assess the impact of this on the giant ibis. We used a Random Forest Classifier to determine the changes and we tested the impact of land use and geographical covariates using spatially explicit regression models. We found an overall reduction of surface water availability of 4.16%. This was predominantly driven by the presence of Economic Land Concessions and roads which increased the probability of extreme drying and flooding events. The presence of protected areas reduced these probabilities. We found changes in precipitation patterns over the wider landscape did not correlate with changes in surface water availability, supporting the overriding influence of land use change. 98% of giant ibis nests recorded during the time period were found within 25m of surface water during the dry season, highlighting their dependency on surface water. The overall surface water decline resulted in a 25% reduction in dry season suitable habitat for the giant ibis. Although absolute changes in surface water over the whole area were relatively small, the impact on the highest quality habitat for ibis is disproportionate and therefore threatens its populations. Defining the threats to such an endangered species is crucial for effective management.

Does Thinking and Working Politically improve support for social business? Evidence from a water business in Cambodia

AbstractMotivationSocial business is business that aims primarily to achieve social ends, while at least covering its costs. Social business has been put forward as a means to achieve development aims, such as the Sustainable Development Goals (SDGs). Thinking and Working Politically (TWP) is an approach to ensure development interventions are politically feasible and not stymied by political opposition. Are the two approaches compatible?PurposeThe article asks whether social business can ally with TWP for more effective development, taking a social business for water provision in Cambodia as a case in point.Methods and approachA review of development policy literature on social business and TWP is combined with data we collected from fieldwork in Cambodia from November 2018 to February 2019. We interviewed key informants from social business, UNICEF, and government in the capital. At two water kiosks in eastern Cambodia, one successful the other less so, we interviewed 2 kiosk operators, 20 customers, and local leaders; we held four focus groups of customers; and we observed operations at the kiosks. Data was analysed using an ethnographic, or immersive, qualitative approach.FindingsIn this case, UNICEF intuitively used TWP to connect a social business to government departments. Water kiosks depended heavily on local political dynamics. We found Commune officials mindful of their standing in local society who often had the interests of the local community in their hearts, but the compatibility of TWP and social business at the local project level is variable.Policy implicationsTWP can potentially help development actors supporting social business to make political connections, in this case to appropriate government departments and local official. The key, however, is to understand context. The danger is to view social business as a turnkey intervention that can be used without adaptation to context, without consideration of local politics. Donors supporting social business need to appraise each business, case by case.Donors might also want to consider the motivations of international companies partnering with social business, particularly when different development objectives might be in conflict.

Monitoring terrestrial wildlife by combining hybridization capture and metabarcoding data from waterhole environmental DNA

In conservation science, observation-based methods are generally applied to wildlife monitoring. While useful, such approaches are often restricted to well-characterized and conspicuous species. Environmental DNA (eDNA) can complement observation-dependent surveys, as sample collection is generally less labor-intensive. Furthermore, eDNA can be used to simultaneously detect multiple taxa in various habitats. Most eDNA applications rely on short PCR product-based meta-barcoding approaches. However, such approaches may be less robust when applied to genetically uncharacterized species. Hybridization capture techniques while less sensitive than metabarcoding, can identifying divergent sequences, especially those obtained from highly degraded DNA. To assess eDNA based methods for surveillance in a conservation context, we collected samples during the dry season from randomly selected waterholes from a protected area in eastern Cambodia. We applied both hybridization capture enrichment and metabarcoding targeting mammal mitogenomes to water (N = 46) and sediment (N = 10) samples. Seventeen species were detected, including 11 mammals, three amphibians, two reptiles, and one bird. Six species overlapped between the two applied methods. Seven species were hybridization capture-specific detections, and four were metabarcoding-specific. Metabarcoding was more sensitive to abundant or large body-size species while hybridization capture provided more mitogenomic information. While both methods have some advantages over observational approaches, combining them may improve the sensitivity, number of species detected and amount of genetic information obtained from eDNA. We demonstrate that eDNA from tropical forest waterholes can be used to determine the presence of wildlife that may be difficult to detect using other observational approaches.

Early Cretaceous volcanic-arc magmatism in the Dalat-Kratie Fold Belt of eastern Cambodia: implications for the lithotectonic evolution of the Indochina terrane

Mesozoic granitic plutons are found throughout the Indochina terrane of eastern Cambodia and southern Vietnam. The granitic rocks range in age from Early Triassic (240 Ma) to Late Cretaceous (80 Ma) and record distinct tectonomagmatic periods associated with subduction of the Paleotethys and Paleo-Pacific oceans. Samples collected from the Snoul pluton, eastern Cambodia are composed of silicic and intermediate dioritic rocks, and basalt. The quartz diorites and diorites are magnesian, metaluminous, calcic to calc-alkalic, and similar to volcanic-arc granitoids whereas the basaltic rocks are compositionally similar to within-plate basalt. Zircon U-Pb geochronology and Lu-Hf isotopes and whole rock Sr-Nd isotopes show that the silicic rocks are Albian and isotopically juvenile (107.5 ± 0.3 Ma, 109.1 ± 0.4 Ma; εHf(t) = +7.0–+17.0; 87Sr/86Sri = 0.704313–0.707681; εNd(t) = +3.1–+4.9). Fractional crystallization modeling using a dioritic composition as the parental magma demonstrates that it is possible to generate the quartz diorite compositions under oxidizing (ΔFMQ +1) and hydrous (H2O = 2 wt%) conditions suggesting that they are consanguineous. The isotopically juvenile nature of the dioritic rocks and their compositional similarity (SiO2 ≥ 56 wt%, Al2O3 ≥ 15 wt%, Sr ≥ 400 ppm, Y ≤ 18 ppm, Yb ≤ 1.9 ppm) to adakitic rocks indicates that the parental magmas of the Snoul pluton were likely derived by partial melting of juvenile mafic basement rocks of the Indochina terrane. Moreover, Early Cretaceous plutonic rocks of Cambodia are isotopically distinct from plutonic rocks of similar age and tectonic setting from Vietnam suggesting that there could be a lithotectonic domain boundary within the Southern Indochina terrane. In contrast, the basaltic rocks likely record a temporally distinct period of magmatism associated with Late Cenozoic tensional plate stress.

United States Secret War in Laos: Long-Term Environmental Impacts of the Use of Chemical Weapons

In 1959, the United States Central Intelligence Agency (CIA) operation, against the Pathet Lao insurgences and Viet Mien military troops and supply route, began. The Ho Chi Minh Trail was developed after the North Vietnam government and military decided to reunify South and North Vietnam. The People’s Army of Vietnam (PAVN) then connected the old trails leading from North Vietnam panhandle southward into eastern Laos, Cambodia and South Vietnam. Starting from Hanoi, the primary trail turned southwest into Laos and eastern Cambodia before branching into South Vietnam. Beginning in 1960s, the volume of traffic on the network of trails expanded significantly, but it still took more than a month’s march, by foot and bicycle, to travel from North to South Vietnam. Ho Chi Minh Trail traffic was impacted by repeatedly by Royal Laotian Air Force (RLAF), which was supported by US Air Force tactical herbicide spraying (Operation Ranch Hand program), and US Air Force bombing runs. By the late 1960s, the trail was improved and could accommodate heavy trucks in some sections and was used to supply the annual needs of over one hundred thousand regular PAVN troops active in South Vietnam. By 1974, the trail was a well-marked series of jungle roads (some of them paved) with underground support facilities such as hospitals, fuel-storage tanks, and supply caches with weapons. The Ho Chi Minh Trail was the major supply route for PAVN forces that overran Republic of Vietnam (RV) forces in 1975 and unified Vietnam. The primary objective of this paper is to determine the environmental and human health impacts of RLAF and US Air Force secret spraying of tactical herbicides on Ho Chi Minh Trail in Laos.

Assessing the status of the Green Peafowl’s “expected stronghold” in dry forests along the Salawin River, north-west Thailand

Summary The suitable habitats of the Endangered Green Peafowl Pavo muticus have declined by 80% over the past century due to extensive anthropogenic degradation. Currently, only six strongholds remain in mainland South-east Asia. While there are estimates of the species’ presence and status in five of these, the sixth one, defined as an “expected stronghold” located in the suitable dry forest along the Salawin River between Thailand and Myanmar, is not well documented. This study assessed the status of the area as a stronghold for the Green Peafowl’s long-term survival by estimating 1) the population density, 2) the current extension of suitable habitats, and 3) the threats to its survival. The area had an estimated density of 0.27 calling males/km2 (CI = 0.07–1.01) inhabiting 9,154 km2 of a mosaic of forest types, including mixed dry pine, mixed deciduous, and dry dipterocarp forests. Higher estimates were reported in other strongholds, including 0.8 birds/km2 in Bago Yoma (Myanmar), 15.8 birds/km2 in north-east Thailand, 1.13–11.34 birds/km2 in HuaiKhaKhaeng Wildlife Sanctuary (Thailand), 0.15–1.7 birds/km2 in northern Cambodia, and 0.15–4.69 birds/km2 in eastern Cambodia / south-central Vietnam. Hunting, habitat disturbance, and the presence of humans posed the greatest danger to the species across the surveyed area. Our results confirm the potential of the area for the species’ long-term survival. However, this “expected stronghold,” which could sustain a population of over 10 calling males/km2 like other high-quality strongholds, is in dire need of a comprehensive management plan to help reduce anthropogenic pressure. Ultimately, transboundary management between Thailand and Myanmar is crucial for the long-term repopulation of this stronghold.

Triple therapy with artemether–lumefantrine plus amodiaquine versus artemether–lumefantrine alone for artemisinin-resistant, uncomplicated falciparum malaria: an open-label, randomised, multicentre trial

SummaryBackgroundLate treatment failures after artemisinin-based combination therapies (ACTs) for falciparum malaria have increased in the Greater Mekong subregion in southeast Asia. Addition of amodiaquine to artemether–lumefantrine could provide an efficacious treatment for multidrug-resistant infections.MethodsWe conducted an open-label, randomised trial at five hospitals or health centres in three locations (western Cambodia, eastern Cambodia, and Vietnam). Eligible participants were male and female patients aged 2–65 years with uncomplicated Plasmodium falciparum malaria. Patients were randomly allocated (1:1 in blocks of eight to 12) to either artemether–lumefantrine alone (dosed according to WHO guidelines) or artemether–lumefantrine plus amodiaquine (10 mg base per kg/day), both given orally as six doses over 3 days. All received a single dose of primaquine (0·25 mg/kg) 24 h after the start of study treatment to limit transmission of the parasite. Parasites were genotyped, identifying artemisinin resistance. The primary outcome was Kaplan-Meier 42-day PCR-corrected efficacy against recrudescence of the original parasite, assessed by intent-to-treat. Safety was a secondary outcome. This completed trial is registered at ClinicalTrials.gov (NCT03355664).FindingsBetween March 18, 2018, and Jan 30, 2020, 310 patients received randomly allocated treatment; 154 received artemether–lumefantrine alone and 156 received artemether–lumefantrine plus amodiaquine. Parasites from 305 of these patients were genotyped. 42-day PCR-corrected treatment efficacy was noted in 151 (97%, 95% CI 92–99) of 156 patients with artemether–lumefantrine plus amodiaquine versus 146 (95%, 89–97) of 154 patients with artemether–lumefantrine alone; hazard ratio (HR) for recrudescence 0·6 (95% CI 0·2–1·9, p=0·38). Of the 13 recrudescences, 12 were in 174 (57%) of 305 infections with pfkelch13 mutations indicating artemisinin resistance, for which 42-day efficacy was noted in 89 (96%) of 93 infections with artemether–lumefantrine plus amodiaquine versus 73 (90%) of 81 infections with artemether–lumefantrine alone; HR for recrudescence 0·44 (95% CI 0·14–1·40, p=0·17). Artemether–lumefantrine plus amodiaquine was generally well tolerated, but the number of mild (grade 1–2) adverse events, mainly gastrointestinal, was greater in this group compared with artemether–lumefantrine alone (vomiting, 12 [8%] with artemether–lumefantrine plus amodiaquine vs three [2%] with artemether–lumefantrine alone, p=0·03; and nausea, 11 [7%] with artemether–lumefantrine plus amodiaquine vs three [2%] with artemether–lumefantrine alone, p=0·05). Early vomiting within 1 h of treatment, requiring retreatment, occurred in no patients of 154 with artemether–lumefantrine alone versus five (3%) of 156 with artemether–lumefantrine plus amodiaquine, p=0·06. Bradycardia (≤54 beats/min) of any grade was noted in 59 (38%) of 154 patients with artemether–lumefantrine alone and 95 (61%) of 156 with artemether–lumefantrine plus amodiaquine, p=0·0001.InterpretationArtemether–lumefantrine plus amodiaquine provides an alternative to artemether–lumefantrine alone as first-line treatment for multidrug-resistant P falciparum malaria in the Greater Mekong subregion, and could prolong the therapeutic lifetime of artemether–lumefantrine in malaria-endemic populations.FundingBill & Melinda Gates Foundation, Wellcome Trust.

Miliusa microphylla (Annonaceae), a new species from Thailand as evidenced by morphology and plastid phylogeny, with M. glandulifera, a new record for Thailand

On the basis of expansive molecular phylogenetic analyses of the genus Miliusa (Annonaceae) utilising up to seven plastid DNA regions, four major clades are identified: clades A, B, C and D. Members of clade C possess axillary inflorescences and crescent-shaped to semicircular glandular structures at the base or (slightly) higher inside the inner petals. In this clade, accessions of M. mollis are recovered as a monophyletic group, divided into two major clades. One of them is recognised as a new species, M. microphylla, which differs from the other (M. mollis) in the following characters: pedicel length, as well as glandular structures and indumentum on the inner petals. The new species is endemic to southeastern Thailand, whereas M. mollis has a much wider distribution (central, eastern, northeastern, northern and peninsular Thailand plus Cambodia and Vietnam). In addition, M. glandulifera, a new record for Thailand, is retrieved as the sister group of a clade composed of M. microphylla and M. mollis. The name M. glandulifera is lectotypified and the description of M. glandulifera is emended, with the information on mature monocarps added. The conservation status of M. microphylla and M. glandulifera is provisionally assessed. A revised key to the species in clade C in Thailand is provided. The phylogenetic position of M. nakhonsiana and M. sessilis in clade C, as well as of M. chantaburiana and M. eupoda in clade B is confirmed for the first time.

Theory of change: Drama and arts-based community engagement for malaria research and elimination in Cambodia.

Background: Across the Greater Mekong Sub-region, malaria persists in isolated communities along international borders. Arts and drama have been used to reach to communities in Cambodia to engage them in malaria research, prevention and control. The "Village Drama Against Malaria" (VDAM) project was conducted in north eastern and western Cambodia: Stung Treng; Battambang and Pailin provinces during 2016 to 2019. In total, VDAM reached 55 rural villages, 2,378 student participants and 43,502 audience members. Methods: This article presents the results of two stakeholder-led evaluation workshops in which participants collaboratively developed theories of change to better understand the potential and actual impact of arts and drama-based activities on malaria in these communities. The workshops had a particular focus on identifying areas for monitoring and evaluation so that impact can be measured. Workshop participants included village malaria workers, community leaders, professional and student drama performers, and representatives from the local health authorities and the national malaria control programme. Results: Five broad areas were identified as relevant for monitoring and evaluation: logistical and practical challenges; embeddedness and reach of engagement; health knowledge and confidence of young people; effectiveness of communications; impact on malaria. These areas align well with the monitoring and evaluation conducted to date and point to additional opportunities for data collection. Conclusions: The findings from these workshops will inform future engagement strategies, for example, we may engage a smaller number of young people but over a longer period and more in-depth.

Theory of change: Drama and arts-based community engagement for malaria research and elimination in Cambodia

Background: Across the Greater Mekong Sub-region, malaria persists in isolated communities along international borders. Arts and drama have been used to reach to communities in Cambodia to engage them in malaria research, prevention and control. The “Village Drama Against Malaria” (VDAM) project was conducted in north eastern and western Cambodia: Stung Treng; Battambang and Pailin provinces during 2016 to 2019. In total, VDAM reached 55 rural villages, 2,378 student participants and 43,502 audience members. Methods: This article presents the results of two stakeholder-led evaluation workshops in which participants collaboratively developed theories of change to better understand the potential and actual impact of arts and drama-based activities on malaria in these communities. The workshops had a particular focus on identifying areas for monitoring and evaluation so that impact can be measured. Workshop participants included village malaria workers, community leaders, professional and student drama performers, and representatives from the local health authorities and the national malaria control programme. Results: Five broad areas were identified as relevant for monitoring and evaluation: logistical and practical challenges; embeddedness and reach of engagement; health knowledge and confidence of young people; effectiveness of communications; impact on malaria. These areas align well with the monitoring and evaluation conducted to date and point to additional opportunities for data collection. Conclusions: The findings from these workshops will inform future engagement strategies, for example, we may engage a smaller number of young people but over a longer period and more in-depth.

Home range, habitat selection, density, and diet of golden jackals in the Eastern Plains Landscape, Cambodia.

We used radiocollars and GPS collars to determine the movements and habitat selection of golden jackals (Canis aureus) in a seasonally dry deciduous forest with no human settlements in eastern Cambodia. We also collected and analyzed 147 scats from jackals to determine their seasonal diet and prey selection. The mean (± SE) annual size of home-range ranges (47.1 ± 2.5 km2; n = 4), which were mutually exclusive between mated pairs, was considerably larger than that previously reported for this species, resulting in an extremely low density (0.01 jackal/km2). The unusually large home ranges and low density probably were due to the harsh dry season when most understory vegetation is burned and nearly all waterholes dry up, thereby causing a large seasonal decline in the availability of small vertebrate prey. Resident groups consisted of an alpha pair, but no betas, and were situated only in areas not occupied by leopards (Panthera pardus) and dholes (Cuon alpinus). Jackals avoided dense forests and streams, and had a strong selection for dirt roads, possibly to avoid larger predators. Overall the jackal diet was diverse, with at least 16 prey items identified, and there was no significant difference in diet composition between the cool-dry and hot-dry seasons. Scat analysis showed that the main food items consumed by jackals were processional termites (Hospitalitermes spp.; 26% biomass consumed), followed by wild pig (Sus scrofa; 20%), muntjac (Muntiacus vaginalis; 20%), and civets (17%). Compared to available biomass, jackals were not random in their consumption of ungulates because muntjac were selectively consumed over larger ungulate species. Dietary overlap with dholes and leopards was relatively low, and consumption patterns indicated jackals were preying on ungulates rather than scavenging from kills of larger carnivores. Our results showed that the jackal is an extremely adaptable and opportunistic species that exhibits unique behaviors to survive in an extreme environment near the edge of its distribution.

Theory of change: Drama and arts-based community engagement for malaria research and elimination in Cambodia

Background: Across the Greater Mekong Sub-region, malaria persists in isolated communities along international borders. Arts and drama have been used to reach to communities in Cambodia to engage them in malaria research, prevention and control. The "Village Drama Against Malaria" (VDAM) project was conducted in north eastern and western Cambodia: Stung Treng; Battambang and Pailin provinces during 2016 to 2019. In total, VDAM reached 55 rural villages, 2,378 student participants and 43,502 audience members. Methods: This article presents the results of two stakeholder-led evaluation workshops in which participants collaboratively developed theories of change to better understand the potential and actual impact of arts and drama-based activities on malaria in these communities. The workshops had a particular focus on identifying areas for monitoring and evaluation so that impact can be measured. Workshop participants included village malaria workers, community leaders, professional and student drama performers, and representatives from the local health authorities and the national malaria control programme. Results: Five broad areas were identified as relevant for monitoring and evaluation: logistical and practical challenges; embeddedness and reach of engagement; health knowledge and confidence of young people; community-level malaria outcomes; impact on malaria. These areas align well with the monitoring and evaluation conducted to date and point to additional opportunities for data collection. Conclusions: The findings from these workshops will inform future engagement strategies, for example, we may engage a smaller number of young people but over a longer period and more in-depth.

Diet and Prey Selection of Dholes in Evergreen and Deciduous Forests of Southeast Asia

ABSTRACTEndangered dholes (Cuon alpinus) are restricted to small and declining populations in Southeast Asia, and little is known about how their ecology differs within the region. We used DNA‐confirmed scats and prey surveys to determine the seasonal diet and prey selection of dholes in 2 different landscapes that dominate Southeast Asia: closed evergreen forests in hilly terrain in northern Laos, and open deciduous forests in relatively flat terrain in eastern Cambodia. On both sites, muntjac (Muntiacus spp.; 20–28 kg) was the dominant prey item and was selectively consumed over other ungulates in all seasons. Our findings differ from previous conclusions, based largely on studies from India, that the preferred prey weight range of dholes was either 40–60 kg or 130–190 kg. Other important prey were sambar (Rusa unicolor) in Laos, and wild pig (Sus scrofa) and banteng (Bos javanicus) in Cambodia. Seasonal differences in overall diet occurred in Laos, but not Cambodia, primarily because of an increase in livestock consumption. The mean number of dhole scats in group defecation sites was higher in Cambodia (5.9 ± 0.5 [SE]) than Laos (2.4 ± 0.2), suggesting pack sizes were larger in Cambodia. Our results suggest that regardless of land cover type, prey diversity, or pack size, the management of muntjac will be important for conserving dhole populations in Southeast Asia. In Laos, we recommend that local villagers remove livestock from the protected area during the hot‐dry season to reduce livestock predation by dholes. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.

Development of copy number assays for detection and surveillance of piperaquine resistance associated plasmepsin 2/3 copy number variation in Plasmodium falciparum

BackgroundLong regarded as an epicenter of drug-resistant malaria, Southeast Asia continues to provide new challenges to the control of Plasmodium falciparum malaria. Recently, resistance to the artemisinin combination therapy partner drug piperaquine has been observed in multiple locations across Southeast Asia. Genetic studies have identified single nucleotide polymorphisms as well as copy number variations in the plasmepsin 2 and plasmepsin 3 genes, which encode haemoglobin-degrading proteases that associate with clinical and in vitro piperaquine resistance.ResultsTo accurately and quickly determine the presence of copy number variations in the plasmepsin 2/3 genes in field isolates, this study developed a quantitative PCR assay using TaqMan probes. Copy number estimates were validated using a separate SYBR green-based quantitative PCR assay as well as a novel PCR-based breakpoint assay to detect the hybrid gene product. Field samples from 2012 to 2015 across three sites in Cambodia were tested using DNA extracted from dried blood spots and whole blood to monitor the extent of plasmepsin 2/3 gene amplifications, as well as amplifications in the multidrug resistance transporter 1 gene (pfmdr1), a marker of mefloquine resistance. This study found high concordance across all methods of copy number detection. For samples derived from dried blood spots, a success rate greater than 80% was found in each assay, with more recent samples performing better. Evidence of extensive plasmepsin 2/3 copy number amplifications was observed in Pursat (94%, 2015) (Western Cambodia) and Preah Vihear (87%, 2014) (Northern Cambodia), and lower levels in Ratanakiri (16%, 2014) (Eastern Cambodia). A shift was observed from two copies of plasmepsin 2 in Pursat in 2013 to three copies in 2014–2015 (25% to 64%). Pfmdr1 amplifications were absent in all samples from Preah Vihear and Ratanakiri in 2014 and absent in Pursat in 2015.ConclusionsThe multiplex TaqMan assay is a robust tool for monitoring both plasmepsin 2/3 and pfmdr1 copy number variations in field isolates, and the SYBR-green and breakpoint assays are useful for monitoring plasmepsin 2/3 amplifications. This study shows increasing levels of plasmepsin 2 copy numbers across Cambodia from 2012 to 2015 and a complete reversion of multicopy pfmdr1 parasites to single copy parasites in all study locations.

Impact of the first-line treatment shift from dihydroartemisinin/piperaquine to artesunate/mefloquine on Plasmodium vivax drug susceptibility in Cambodia.

BackgroundCambodia is the epicentre of the emergence of Plasmodium falciparum drug resistance. Much less is known regarding the drug susceptibility of the co-endemic Plasmodium vivax. Only in vitro drug assays can determine the parasite’s intrinsic susceptibility, but these are challenging to implement for P. vivax and rarely performed.ObjectivesTo evaluate the evolution of Cambodian P. vivax susceptibility to antimalarial drugs and determine their association with putative markers of drug resistance.Methods In vitro response to three drugs used in the past decade in Cambodia was measured for 52 clinical isolates from Eastern Cambodia collected between 2015 and 2018 and the sequence and copy number variation of their pvmdr1 and pvcrt genes were analysed. pvmdr1 polymorphism was also determined for an additional 250 isolates collected in Eastern Cambodia between 2014 and 2019.ResultsAmong the 52 cryopreserved isolates tested, all were susceptible to the three drugs, with overall median IC50s of 16.1 nM (IQR 11.4–22.3) chloroquine, 3.4 nM (IQR 2.1–5.0) mefloquine and 4.6 nM (IQR 2.7–7.0) piperaquine. A significant increase in chloroquine and piperaquine susceptibility was observed between 2015 and 2018, unrelated to polymorphisms in pvcrt and pvmdr1. Susceptibility to mefloquine was significantly lower in parasites with a single mutation in pvmdr1 compared with isolates with multiple mutations. The proportion of parasites with this single mutation genotype increased between 2014 and 2019.Conclusions P. vivax with decreased susceptibility to mefloquine is associated with the introduction of mefloquine-based treatment during 2017–18.

Integrative taxonomic analysis reveals a new species of Leptobrachium (Anura: Megophryidae) from north-eastern Cambodia and central Vietnam

ABSTRACT Species boundaries within the red-eyed Leptobrachium of southern Indochina have been uncertain. Leptobrachium pullum and L. mouhoti from upper and lower elevations, respectively, of the Langbian Plateau of southern Vietnam and eastern Cambodia differ in body size but have relatively low interspecific mitochondrial DNA divergence, leading to speculation that these might represent a single species with an elevational cline in body size. The recent discovery of an allopatric high-elevation population of red-eyed Leptobrachium on the Kon Tum Plateau (= Central Highlands) of north-eastern Cambodia and central Vietnam has been referred to both species, and to a putatively undescribed species. We examine variation in morphology of adults and tadpoles, mitochondrial DNA, 11 nuclear genes and advertisement calls, and show corroborating lines of evidence for the existence of three species of red-eyed Leptobrachium in southern Indochina. Although the three species are reciprocally monophyletic in mitochondrial DNA, their shallow mitochondrial DNA divergences are not mirrored by morphology, advertisement calls, or – in part – nuclear DNA, and probably reflect past mitochondrial introgression rather than recent speciation. The Central Highlands taxon is described herein as a new species. http://www.zoobank.org/urn:lsid:zoobank.org:pub:CE6650AF-D9FB-40F4-8A2E-9B4E23AAC205

Apis dorsata Honey Hunting and Honey Trading in Mondulkiri (Eastern Cambodia)

The Asian giant honey bee, Apis dorsata F., builds its massive single comb open nest (Figure 1) under tree branches, cliff overhangs or eaves of urban structures (Oldroyd & Wongsiri, 2006; Paar, Ol...

African Swine Fever Virus - Persistence in Different Environmental Conditions and the Possibility of its Indirect Transmission.

Since 2007, African swine fever (ASF) has posed a serious threat to the European swine industry. In Poland, the numbers of reported outbreaks in pigs and affected areas grow every year. In 2018, the disease was noted in Western Europe, in Belgium specifically, where several hundred infected wild boars have been detected so far. In 2018, the virus unexpectedly emerged in pig holdings in eastern China, northern Mongolia, Vietnam, and Cambodia, causing worldwide concern about its further spread. Since there is still no vaccine available, the only approach to control the disease is biosecurity. Identification of potential sources of the virus is extremely important in light of its phenomenal survivability. The review summarises the current knowledge about ASFV survivability and resistance to environmental conditions, and discusses the role of indirect contact in spreading the disease.

A new caruncle-bearing fanged frog (Limnonectes, Dicroglossidae) from Laos and Thailand.

A new species of the dicroglossid frog genus Limnonectes is described from recent and historical museum specimens collected in central and southern Laos and northeastern Thailand. Limnonectessavansp. nov. has males that bear a caruncle on top of the head, and most closely resembles L.dabanus from adjacent southern Vietnam and eastern Cambodia. However, the new species is readily distinguished from L.dabanus, and all other caruncle-bearing species of Limnonectes in mainland Southeast Asia, by its adult and larval morphology, mitochondrial DNA, and advertisement call. Its description brings the total number of caruncle-bearing species of Limnonectes to six.