The radical cure of Plasmodium vivax and P. ovale requires treatment with primaquine or tafenoquine to clear dormant liver stages. Either drug can induce haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, necessitating screening. The reference diagnostic method for G6PD activity is ultraviolet (UV) spectrophotometry; however, a universal G6PD activity threshold above which these drugs can be safely administered is not yet defined. Our study aimed to quantify assay-based variation in G6PD spectrophotometry and to explore the diagnostic implications of applying a universal threshold. Individual-level data were pooled from studies that used G6PD spectrophotometry. Studies were identified via PubMed search (25 April 2018) and unpublished contributions from contacted authors (PROSPERO: CRD42019121414). Studies were excluded if they assessed only individuals with known haematological conditions, were family studies, or had insufficient details. Studies of malaria patients were included but analysed separately. Included studies were assessed for risk of bias using an adapted form of the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Repeatability and intra- and interlaboratory variability in G6PD activity measurements were compared between studies and pooled across the dataset. A universal threshold for G6PD deficiency was derived, and its diagnostic performance was compared to site-specific thresholds. Study participants (n = 15,811) were aged between 0 and 86 years, and 44.4% (7,083) were women. Median (range) activity of G6PD normal (G6PDn) control samples was 10.0 U/g Hb (6.3–14.0) for the Trinity assay and 8.3 U/g Hb (6.8–15.6) for the Randox assay. G6PD activity distributions varied significantly between studies. For the 13 studies that used the Trinity assay, the adjusted male median (AMM; a standardised metric of 100% G6PD activity) varied from 5.7 to 12.6 U/g Hb (p < 0.001). Assay precision varied between laboratories, as assessed by variance in control measurements (from 0.1 to 1.5 U/g Hb; p < 0.001) and study-wise mean coefficient of variation (CV) of replicate measures (from 1.6% to 14.9%; p < 0.001). A universal threshold of 100% G6PD activity was defined as 9.4 U/g Hb, yielding diagnostic thresholds of 6.6 U/g Hb (70% activity) and 2.8 U/g Hb (30% activity). These thresholds diagnosed individuals with less than 30% G6PD activity with study-wise sensitivity from 89% (95% CI: 81%–94%) to 100% (95% CI: 96%–100%) and specificity from 96% (95% CI: 89%–99%) to 100% (100%–100%). However, when considering intermediate deficiency (<70% G6PD activity), sensitivity fell to a minimum of 64% (95% CI: 52%–75%) and specificity to 35% (95% CI: 24%–46%). Our ability to identify underlying factors associated with study-level heterogeneity was limited by the lack of availability of covariate data and diverse study contexts and methodologies. Our findings indicate that there is substantial variation in G6PD measurements by spectrophotometry between sites. This is likely due to variability in laboratory methods, with possible contribution of unmeasured population factors. While an assay-specific, universal quantitative threshold offers robust diagnosis at the 30% level, inter-study variability impedes performance of universal thresholds at the 70% level. Caution is advised in comparing findings based on absolute G6PD activity measurements across studies. Novel handheld quantitative G6PD diagnostics may allow greater standardisation in the future.

This study explores the critical issue of understanding the potential impacts of climate change on the habitat suitability of the highly endangered forest-dwelling Mangshan pit viper (Protobothrops mangshanensis) in China. Through the application of the MaxEnt model, high-resolution bioclimatic datasets, and species occurrence data, the research aims to elucidate the spatial and temporal dynamics of P. mangshanensis distribution from the present to the years 2050 and 2070. Through the integration of three climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and exploring different shared socioeconomic pathway (SSP) scenarios (SSP126, SSP370, and SSP585), the study seeks to provide comprehensive insights into the potential variations in habitat suitability under diverse future climate conditions. The methodology employed involves the construction of the MaxEnt model utilizing the BioClim dataset and 83 species occurrence points. The SSP scenarios mentioned above represent future climate change scenarios, and the accuracy of the model is evaluated using the area under the receiver-operating characteristic (ROC) curve (AUC). Key findings reveal that the MaxEnt model exhibits high accuracy (AUC = 0.998), pinpointing the current suitable habitat for P. mangshanensis to be confined to the Mangshan area within the Nanling Mountains, covering an approximate area of 1023.12 km². However, projections based on future climate scenarios suggest notable shifts in habitat suitability dynamics. While potential suitable habitats may emerge in the northwest of the current range, the existing suitable habitats are anticipated to undergo significant reduction or even complete disappearance. Notably, precipitation during the driest month emerges as a critical determinant influencing the distribution of the species. In conclusion, the study underscores the exacerbating impact of climate change on habitat deterioration and survival risks for P. mangshanensis, emphasizing the urgent need for conservation measures to safeguard the remaining suitable habitats for this endangered species. The implications of these findings are far-reaching, with the anticipated contraction of the snake’s range potentially leading to its disappearance and increased habitat fragmentation. By shedding light on the potential distributional changes of P. mangshanensis in Mangshan, the research provides valuable insights for informing targeted conservation strategies and policy interventions aimed at mitigating the adverse effects of climate change on endangered species.

Raptors are high-trophic-level predators and scavengers that are sensitive to habitat alteration, human disturbance, and climate variability, yet province-wide assessments of their habitat suitability and climate-change responses remain limited in subtropical China. Hunan Province, located along the inland section of the East Asian–Australasian Flyway, contains complex mountain systems, plains, wetlands, and land-use mosaics that may support diverse raptor assemblages. Based on raptor survey records collected across Hunan from January 2022 to July 2023, we used biomod2 ensemble species distribution models to assess current habitat suitability, identify key environmental predictors, and project future changes under the SSP2-4.5 and SSP5-8.5 scenarios for the 2050s and 2090s. We recorded 39 raptor species and retained 3637 valid geographic locations and 4855 observed individuals after data cleaning. Nine representative species were further selected to construct 22 species–season combinations covering resident species, summer visitors, winter visitors, and four phenological stages. The EMwmean weighted ensemble model consistently outperformed the best single models, increasing mean AUC from 0.882 to 0.970 and the mean TSS from 0.611 to 0.845. Temperature seasonality (BIO4), the Human Footprint Index (HFP), precipitation in the driest month (BIO14), and the Normalized Difference Vegetation Index (NDVI) were the dominant predictors, although their relative importance varied among residency types and phenological stages. Under current conditions, highly suitable and most suitable habitats covered 65,259.67 km², accounting for 30.81% of Hunan Province, and were mainly concentrated in western, southern, and eastern mountain regions. Future projections indicated a marked contraction of high-suitability habitats, especially under SSP5-8.5, with no HSI > 0.6 habitat identified by the 2090s. High-suitability habitats also became increasingly concentrated at higher elevations. These findings identify mountain regions as key conservation priorities and provide a spatial framework for climate-adaptive raptor conservation in Hunan Province.

This study focuses on understanding the behavior and activity patterns of the critically endangered Protobothrops mangshanensis in China in order to better provide scientific data for upcoming artificial breeding and propagation efforts. We conducted a long-term observation of 15 Mangshan pit vipers at different sites in Hunan Province during the summer and autumn of 2021. Our methods involved analyzing the influence of environmental factors such as temperature, relative humidity, and light condition on the snakes’ day and night activity and behaviors. The results revealed that the wild behaviors of Protobothrops mangshanensis include resting, sunbathing, crawling, and exploring, with distinct rhythms in their diel behavior. The snakes’ diel activity exhibits three peak periods which may be related to food activity and sunbathing. This study also highlights the complex interplay of environmental factors on the activity of Protobothrops mangshanensis. Relative humidity was identified as a critical factor accounting for the difference in activity between observation groups. There was little inter-individual variation among the 15 Protobothrops mangshanensis, even though these snakes used terrestrial and arboreal habitats under different environmental conditions. These findings enhance our understanding of Protobothrops mangshanensis behavior and provide a basis for effective conservation measures for this rare and critically endangered species.

The critically endangered Mangshan pit viper ( Protobothrops mangshanensis ), endemic to China’s fragmented Nanling Mountain Range, serves as a model to investigate universal drivers of speciation and population collapse in isolated taxa. Using whole-genome resequencing (23 P. mangshanensis ; 41 sympatric relatives), we address how historical biogeography, adaptive divergence, and anthropogenic pressures jointly threaten small populations. Results reveal alarmingly low genetic diversity (θπ = 0.009), 91.92% homozygous SNPs, and negligible gene flow—hallmarks of prolonged isolation and inbreeding. Demographic analyses (PSMC/SMC++) trace population declines to post-Pleistocene habitat fragmentation (~10,000 years ago), a bottleneck shared by mountain-endemic vertebrates globally. Selective sweeps identified 192 genes under adaptation, including DLX5/DLX6 (skeletal growth), Hars (movement suppression), and SPAG6 (reproductive isolation), which collectively drove ecological divergence: increased body size to deter predators, reduced mobility to conserve energy, and reproductive isolation halting hybridization. These genomic signatures reflect a classic speciation trajectory—geographic isolation followed by adaptive and reproductive divergence—common in montane taxa. Critically, the study links extinction risks to synergistic pressures: historical climate shifts fragmenting habitats, contemporary anthropogenic barriers limiting gene flow, and genomic erosion eroding adaptive potential. By integrating paleodemography, climate modeling, and adaptive genomics, we establish a framework applicable to conservation of other fragmented species. Our findings underscore that small populations facing habitat loss and climate change are vulnerable to parallel extinction cascades unless adaptive loci are prioritized in management. This work highlights how genomic tools can disentangle universal speciation mechanisms and extinction drivers, offering actionable strategies for biodiversity preservation in the Anthropocene.