Variable detectability and El-Niño associations with riparian snakes in Sabah, Malaysian Borneo

Although snake populations are suffering numerous local declines, determining the scale of these declines is problematic due to the elusive nature of snakes. Determining the factors associated with species detection is therefore essential for quantifying disturbance effects on populations. From 2017 to 2019, we assessed the detectability associations of five river-associated snake species and all snake detections in general within two logging concessions in Sabah, Malaysian Borneo. Data collected from both stream transects and visual encounter surveys at 47 stream sites were incorporated into an occupancy-modelling framework to determine the climatological, temporal and survey distance associations with species detection probability. Detection probability of riparian snake species was significantly associated with humidity, month (2 spp. each), survey distance and total rainfall over 60 days (1 spp. each). Pooled snake species detectability was significantly positively associated with transect distance and the 2019 El-Niño year, whilst yearly pooled snake species detections in stream transects spiked during El-Niño (2017 = 2.05, 2018 = 2.47, 2019 = 4.5 snakes per km). This study provides new insights into the detectability of riparian rainforest snakes and suggests that future studies should account for short-term (climatological and temporal) and long-term (El-Niño) factors associated with detection probability when surveying and assessing snake populations.

Preclinical Immuno-recognition and Neutralization of Lethality Assessment of a New Polyvalent Antivenom, VINS Snake Venom Antiserum – African IHS®, against Envenomation of Ten African Viperid and Elapid Snakes

Snakebite envenomation is a major health concern in developing countries causing significant mortality and morbidity. With over 1.2 million cases annually caused by medically important snake species belonging to the two families Viperidae (Echis spp. and Bitis spp.) and Elapidae (Naja spp. and Dendroaspis spp.). Several antivenoms are being produced and distributed to western sub-Saharan Africa for treatment of envenomation with the absence of preclinical efficacy studies. The present study evaluated the preclinical efficacy of venoms from Echis leucogaster, Echis ocellatus, Bitis arietans, Bitis gabonica, Naja haje, Naja melanoleuca, Naja nigricollis, Dendroaspis jamesoni, Dendroaspis polylepis and Dendroaspis viridis against a polyvalent Snake Venom Antiserum - African IHS (lyophilised), manufactured by VINS Bioproducts Limited (Telangana, India). Our in vitro results showed that, the SVA- AIHS contains antibodies that are capable of recognizing and binding majority of protein components representative of all eight major protein families of venoms of the snake species tested by double immunodiffusion assay and confirmed by western blot. The venom antiserum exhibited high neutralization efficacy against all the viperid and elapid snake species venoms in in vivo studies and confirmed the manufacturer’s recommended neutralization capacity. This is clear evidence that the VINS polyvalent SVA-AIHS batch tested has strong neutralizing capacity and will be useful in treating envenoming by most African viperid and some elapid snake species.

Case Report: Rotational Thromboelastometry in Taipan Envenomation

Venom-induced consumption coagulopathy (VICC) is one of the most dangerous syndromes caused by snake envenomation and can be caused by several snake species worldwide, including the Australian coastal taipan. Rotational thromboelastometry (ROTEM) provides real-time point-of-care information on all stages of clot formation; however, it has yet to be formally evaluated in the assessment of VICC. We report three cases of Taipan envenomation causing VICC and the associated ROTEM results. The implications for future use of ROTEM in the assessment, management, and further research of VICC are discussed.

Application of DNA Barcoding for the Identification of a Traditional Chinese Medicine Shedan

Background Shedan has a long history of application in Traditional Chinese medicine (TCM), however, Shedan from different original source has been indiscriminately used. So far, there is still a lack of an effective tool to differentiate the original source of Shedan medicinal materials, which brings great risk to the safety and effectiveness of clinical applications. Hence, it is imperative to develop a practicable approach to identify Shedan medicinal materials. Methods The specificity of two pairs of primers, including Folmer’s universal primers and a pair of originally designed primers COISNFF/COISNFR, was tested to screen the more specific primers for further origin identification of Shedan. A total of 253 fresh snake gallbladder samples from 31 morphologically identified snake species were collected and authenticated. Moreover, 51 fresh snake bile samples and 17 fresh bile samples from five other common domestic poultry and livestock (cattle, chicken, duck, pig and sheep) were collected and distinguished using the more specific primers. Additionally, a total of 195 market Shedan samples randomly selected from 18 batches of Shedan medicinal materials were investigated. Sequence definition was executed by querying sequence similarities in GenBank and the Barcode of Life Data System (BOLD), respectively. Results It turned out that the standard COI barcode obtained by COISNFF/COISNFR primers, rather than Folmer’s universal primers, can distinguish all the testing samples from each other in fresh Shedan samples, and COISNFF/COISNFR primers were also specific to snake species and the other four animal species except duck. In terms of market Shedan, 84.6% (165/195) samples can be attributed to 13 snake species from four families and 4.6% (9/195) can be attributed to adulterated chicken species. Conclusion The COI-based DNA barcoding was practicable for species identification of Shedan used in traditional Chinese medicine. The original source of current market Shedan, including adulterated species, has been preliminarily clarified, which provides a foundation for quality control of Shedan medicinal materials.

Predation of the Japanese keelback (Hebius vibakari Boie, 1826) by the Slender racer (Orientocoluber spinalis Peters, 1866)

Background The Slender racer (Orientocoluber spinalis Peters, 1866) has recently been reclassified to the new genus Orientocoluber from Hierophis. Ecological knowledge of this species is limited due to its highly mobile behavior. On 17 July 2020, we captured a female O. spinalis on Oeyeon Island, Boryeong-si, Republic of Korea, and collected its feces for a diet analysis. We observed snake scales from the collected feces and subsequently determined the prey species through morphological and molecular methods. Results We initially hypothesized that the extracted fecal sample scales belonged to H. vibakari, due to their thin keel and rhombus shape. We also amplified H. vibakari DNA from the extracted fecal sample using Illumina sequencing methods. Our morphological and molecular results suggest that O. spinalis predates H. vibakari on Oeyeon Island. Conclusion This is the first report of O. spinalis predating another snake species, ophiophagy, and implies that H. vibakari may be a crucial prey item for O. spinalis on Oeyeon Island.

A comparative study on image-based snake identification using machine learning

Automated snake image identification is important from different points of view, most importantly, snake bite management. Auto-identification of snake images might help the avoidance of venomous snakes and also providing better treatment for patients. In this study, for the first time, it’s been attempted to compare the accuracy of a series of state-of-the-art machine learning methods, ranging from the holistic to neural network algorithms. The study is performed on six snake species in Lar National Park, Tehran Province, Iran. In this research, the holistic methods [k-nearest neighbors (kNN), support vector machine (SVM) and logistic regression (LR)] are used in combination with a dimension reduction approach [principle component analysis (PCA) and linear discriminant analysis (LDA)] as the feature extractor. In holistic methods (kNN, SVM, LR), the classifier in combination with PCA does not yield an accuracy of more than 50%, But the use of LDA to extract the important features significantly improves the performance of the classifier. A combination of LDA and SVM (kernel = 'rbf') is achieved to a test accuracy of 84%. Compared to holistic methods, convolutional neural networks show similar to better performance, and accuracy reaches 93.16% using MobileNetV2. Visualizing intermediate activation layers in VGG model reveals that just in deep activation layers, the color pattern and the shape of the snake contribute to the discrimination of snake species. This study presents MobileNetV2 as a powerful deep convolutional neural network algorithm for snake image classification that could be used even on mobile devices. This finding pave the road for generating mobile applications for snake image identification.

Ecomorphological Study of Scales in Some Genera of the Viperid and Colubrid Snakes (Ophidia: Viperidae: Colubridae)

Ecomorphological studies are aimed to find out the relation between the morphology of organisms and their ecology. Many studies on reptile scale microornamentation indicate that it has important functional values. In this study microornamentation and light reflection of scales’ surface among six viperid and two colubrid snake species in relation to their habitat were examined. To compare microornamentation and light reflection analyses, skin specimens were prepared and analyzed using scanning electron microscopy and FluoVision Imaging System and spectrometer, respectively. The results showed that snake species inhabiting similar habitats had different microornamentation and vice versa. Likely the scale microstructures are more influenced by phylogenetic relationships than by the environment. In examining the scales’ reflection, different species and different body parts reflect various wavelengths of visible light, which relates to ecological condition of them.