Monkeying around with venom: an increased resistance to α-neurotoxins supports an evolutionary arms race between Afro-Asian primates and sympatric cobras

Background Snakes and primates have a multi-layered coevolutionary history as predators, prey, and competitors with each other. Previous work has explored the Snake Detection Theory (SDT), which focuses on the role of snakes as predators of primates and argues that snakes have exerted a selection pressure for the origin of primates’ visual systems, a trait that sets primates apart from other mammals. However, primates also attack and kill snakes and so snakes must simultaneously avoid primates. This factor has been recently highlighted in regard to the movement of hominins into new geographic ranges potentially exerting a selection pressure leading to the evolution of spitting in cobras on three independent occasions. Results Here, we provide further evidence of coevolution between primates and snakes, whereby through frequent encounters and reciprocal antagonism with large, diurnally active neurotoxic elapid snakes, Afro-Asian primates have evolved an increased resistance to α-neurotoxins, which are toxins that target the nicotinic acetylcholine receptors. In contrast, such resistance is not found in Lemuriformes in Madagascar, where venomous snakes are absent, or in Platyrrhini in the Americas, where encounters with neurotoxic elapids are unlikely since they are relatively small, fossorial, and nocturnal. Within the Afro-Asian primates, the increased resistance toward the neurotoxins was significantly amplified in the last common ancestor of chimpanzees, gorillas, and humans (clade Homininae). Comparative testing of venoms from Afro-Asian and American elapid snakes revealed an increase in α-neurotoxin resistance across Afro-Asian primates, which was likely selected against cobra venoms. Through structure-activity studies using native and mutant mimotopes of the α-1 nAChR receptor orthosteric site (loop C), we identified the specific amino acids responsible for conferring this increased level of resistance in hominine primates to the α-neurotoxins in cobra venom. Conclusion We have discovered a pattern of primate susceptibility toward α-neurotoxins that supports the theory of a reciprocal coevolutionary arms-race between venomous snakes and primates.

Epidemiological study of snakebite cases in Sikkim: Risk modeling with regard to the habitat suitability of common venomous snakes

Background Snakebite envenoming is listed as category ‘A’ Neglected Tropical Disease. To achieve the target of WHO (World Health Organization) 2019, it becomes necessary to understand various attributes associated with snakebite including community awareness, improvisation of medical facilities and to map the potential distribution of venomous snakes responsible for the bite. Hence this study is conducted in Sikkim, India to understand the epidemiology of snakebite in Sikkim. The potential distribution and risk mapping of fivecommon venomous snakes are done for effective management of snakebite cases. Methods and findings The snakebite cases registered in six district hospitals and four PHCs (Primary Health Centers) of Sikkim were collected from the year 2011 to 2018. Community survey was also conducted to supplement the data. Ecological Niche Modeling (ENM) was performed to predict the potential habitat of five common venomous snakes of Sikkim. Therisk modeling of snakebite cases was done at the level of Gram Panchayat Unit (GPU) using Geographically Weighted Regression (GWR) and Ordinary Linear Square (OLS) model. We found higher number of male victims inflicted with snakebite envenomation. The potential distribution of the five venomous snakes showed satisfactory mean AUC (Area under Curve) value. Both the models showed significant positive association of snakebite cases with habitat suitability of the venomous snakes.Hospital data revealed no death cases whereas community data reported 24 deaths. Conclusions Death from snakebite reflected in community data but not in hospital data strongly indicates the people’s belief in traditional medicine. Though people of Sikkim have rich traditional knowledge, in case of snakebite traditional practices may be ineffective leading to loss of life. Sensitizing people and improving medical facilities along with proper transport facilities in rural areas might significantly reduce the snakebite casualties in the state.

Serum snakebite therapy

Although the bites of venomous snakes found in Europe are far from so dangerous, cancer bites of a cobra, rattlesnake and other snakes found in India, Africa and America, nevertheless often (in 14%) and bites of our viper lead to death. If this is so, then the desire of researchers to find a correct remedy against poisoning with the poison of a viper that has got into the blood is understandable.

Entangling snakebite dynamics: the spatiotemporal role of rainfall on snake envenoming in Colombia

The role of climate forcing on the population dynamics of infectious diseases has typically been addressed via retrospective analyses of aggregated incidence records over whole political regions. A central question in epidemiology has been whether seasonal and interannual cycles are driven by climate variation, or instead generated by other factors such as poverty or underreporting. Here, we use process-based models to determine the role of rainfall in the dynamics of snakebite, which is one of the main neglected tropical diseases around the world. We combined space-time datasets of snakebite incidence and rainfall for Colombia in combination with stochastic epidemiological models and iterated filtering methods to show the response to rainfall forcing, specifically, modulating the encounter frequency with venomous snakes. We identified six zones with different rainfall patterns to demonstrate that the relationship between rainfall and snakebite incidence was heterogeneous. Rainfall only drives snakebite incidence in regions with marked dry seasons, where rainfall becomes the limiting resource. In addition, the encounter frequency also differs between regions, and it is higher in regions where Bothrops atrox can be found. Our results show how the heterogeneous spatial distribution of snakebite risk seasonality in the country may be related to important traits of venomous snakes' natural history.

Autonomic Dysfunction Following Neurotoxic Snake Envenomation: Does Site of Bite Predispose?

South Asian subcontinent is among the highest burden areas in respect of snake bite. India is commonest place in this subcontinent with mortality following snake envenomation. The four most important venomous snakes in India are cobra (Naja naja) and common krait (Bungarus caeruleus), which are neurotoxic, and the saw-scaled viper (Echis carinatus) and Russell’s viper (Daboia russelii), which are hemotoxic1. Various autonomic dysfunction following neuro-paralytic envenomation with krait and cobra has been reported. Timely recognition and appropriate management of snake envenomation along with autonomic dysfunction helps to reduce morbidity and mortality. Keywords: Autonomic dysfunction, hypertension, antisnake venom, blood pressure.

ONLINE TRAINING ON THE INTRODUCTION AND HANDLING OF THE THREAT OF RATTLESNAKES DURING THE COVID-19 PANDEMIC

Snakes are cold-blooded reptiles that are often found from the lowlands, headlands, soil, trees, freshwater, brackish water, to seawater, except in areas with low temperatures such as the poles. Rattlesnake bites continue to occur anytime and anywhere. Although, currently, there is a covid-19 pandemic in Indonesia. The community needs to know and identify some basic knowledge about snakes. This training was held on April 22, 2020. The method used in this training was demonstration and question and answered through the chat column on Instagram and YouTube accounts for 1 hour. The results of this online training provide additional information and knowledge to the broader community. Also, the number of participants who took part was more significant and scattered throughout Indonesia. Snakes with high venom have a pair of fangs in the upper jaw, and not all highly venomous snakes have triangular heads, such as Bungarus candidus (weling) and Bungarus fasciatus (welang).