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The DNA data of Indian snakes are scanty in the global database, especially from the northeastern states. The present study generated the mitochondrial Cytochrome b gene information of two morphologically identified deadly elapid species from Mizoram. Both, the King Cobra (Ophiophagus hannah) and Banded Krait (Bungarus fasciatus) showed monophyletic clades in the BA topology and cohesively clustered with the database sequences generated from distant geographical locations. The studied O. hannah depicted 2.7–7.6% K2P genetic distances with the specimens collected from China, Vietnam, and Thailand. Further, the northeast Indian B. fasciatus revealed 3.3–4% K2P genetic distance from Chinese, Vietnamese, Thailand, Indonesian, and Australian specimens. The TCS network showed distinct haplotypes for both the species collected from northeast India. The genetic information of these venomous snakes would be helpful for further rapid identification from the museum as well as from road-killed specimens, curbing the venom poaching and medical avenues. [ABSTRACT FROM AUTHOR]

A species' spatial ecology has direct implications for that species' conservation. Far-ranging species may be more difficult to conserve because their movements increase their chances of encountering humans. The movements can take them out of protected areas, which is especially risky for species that are routinely persecuted. The king cobra (Ophiophagus hannah), a large venomous elapid, is subject to anthropogenic pressures, such as persecution and habitat loss. Here we present results from a study using radio telemetry to quantify movements and habitat use of nine king cobras in and around a protected area in Northeast Thailand. This study is the first investigation into the movements and habitat use of king cobras outside of the Western Ghats, India. On average, the tracked king cobra's use areas of 493.42 ± 335.60 ha (95% fixed kernel), moving 183.24 ± 82.63 m per day. King cobras did not remain in intact forested area. Five of the individuals frequently used the human-dominated agricultural areas surrounding the protected area, appearing to make regular use of irrigation canals. Two adult males showed increases in movements during the breeding season. One male's increased breeding season range caused him to venture beyond the protected area, shifting his habitat use from intact forests to scrub in human-dominated areas. King cobras' large home range and willingness to use anthropogenic landscapes merits special consideration from conservation planners. [ABSTRACT FROM AUTHOR]

The parasitic nematode Paracapillaria ( Ophidiocapillaria ) najae De, 1998, found in the Indian cobra Naja naja is redescribed and re-illustrated in the present study. The monocled cobra Naja kaouthia was discovered to be a new host for this parasite in central Thailand. A comprehensive description extending the morphological and molecular characteristics of the parasites is provided to aid species recognition in future studies. The morphometric characters of 41 parasites collected from 5 cobra specimens are compared with those described in the original studies. Phylogenetic analyses using mitochondrial cytochrome c oxidase subunit 1 and nuclear 18S ribosomal RNA genes were performed to provide novel information on the systematics of P. najae . Similar characteristics were observed in the examined nematode samples, despite being found in different hosts, confirming their identity as P. najae . The molecular genetic results support the species status of P. najae , indicating P. najae is well defined and separated from other related nematode species in the family Capillariidae. Morphological descriptions, genetic sequences, evolutionary relationships among capillariids and new host and distribution records of P. najae are discussed. Paracapillaria najae specimens found in the Thai cobra had some morphological variation, and sexual size dimorphism was also indicated. Paracapillaria najae was found to infect various cobra host species and appeared to be common throughout the Oriental regions, consistent with its hosts' distribution.

Conservation of sea snakes is virtually nonexistent in Asia, and its role in human-snake interactions in terms of catch, trade, and snakebites as an occupational hazard is mostly unexplored. We collected data on sea snake landings from the Gulf of Thailand, a hotspot for sea snake harvest by squid fishers operating out of the ports of Song Doc and Khanh Hoi, Ca Mau Province, Vietnam. The data were collected during documentation of the steps of the trading process and through interviewers with participants in the trade. Squid vessels return to ports once per lunar synodic cycle and fishers sell snakes to merchants who sort, package, and ship the snakes to various destinations in Vietnam and China for human consumption and as a source of traditional remedies. Annually, 82 t, roughly equal to 225,500 individuals, of live sea snakes are brought to ports. To our knowledge, this rate of harvest constitutes one of the largest venomous snake and marine reptile harvest activities in the world today. Lapemis curtus and Hydrophis cyanocinctus constituted about 85% of the snake biomass, and Acalyptophis peronii, Aipysurus eydouxii, Hydrophis atriceps, H. belcheri, H. lamberti, and H. ornatus made up the remainder. Our results establish a quantitative baseline for characteristics of catch, trade, and uses of sea snakes. Other key observations include the timing of the trade to the lunar cycle, a decline of sea snakes harvested over the study period (approximately 30% decline in mass over 4 years), and the treatment of sea snake bites with rhinoceros horn. Emerging markets in Southeast Asia drive the harvest of venomous sea snakes in the Gulf of Thailand and sea snake bites present a potentially lethal occupational hazard. We call for implementation of monitoring programs to further address the conservation implications of this large-scale marine reptile exploitation. Cosecha de Serpientes Marinas en el Golfo de Tailandia [ABSTRACT FROM AUTHOR]

The Equatorial Spitting Cobra ( Naja sumatrana ) is a medically important venomous snake species in Southeast Asia. Its wide geographical distribution implies potential intra-specific venom variation, while there is no species-specific antivenom available to treat its envenoming. Applying a protein-decomplexing proteomic approach, the study showed that three-finger toxins (3FTX), followed by phospholipases A 2 (PLA 2 ), were the major proteins well-conserved across N. sumatrana venoms of different locales. Variations were noted in the subtypes and relative abundances of venom proteins. Of note, alpha-neurotoxins (belonging to 3FTX) are the least in the Penang specimen (Ns-PG, 5.41% of total venom proteins), compared with geographical specimens from Negeri Sembilan (Ns-NS, 14.84%), southern Thailand (Ns-TH, 16.05%) and Sumatra (Ns-SU, 10.81%). The alpha-neurotoxin abundance, in general, correlates with the venom's lethal potency. The Thai Naja kaouthia Monovalent Antivenom (NkMAV) was found to be immunoreactive toward the N. sumatrana venoms and is capable of cross-neutralizing N. sumatrana venom lethality to varying degrees (potency = 0.49-0.92 mg/mL, interpreted as the amount of venom completely neutralized per milliliter of antivenom). The potency was lowest against NS-SU venom, implying variable antigenicity of its lethal alpha-neurotoxins. Together, the findings suggest the para-specific and geographical utility of NkMAV as treatment for N. sumatrana envenoming in Southeast Asia.

Envenoming by cobras ( Naja spp.) often results in extensive local tissue necrosis when optimal treatment with antivenom is not available. This study investigated the cytotoxicity of venoms and purified cytotoxins from the Monocled Cobra ( Naja kaouthia ), Taiwan Cobra ( Naja atra ), and Equatorial Spitting Cobra ( Naja sumatrana ) in a mouse fibroblast cell line, followed by neutralization of the cytotoxicity by three regional antivenoms: the Thai Naja kaouthia monovalent antivenom (NkMAV), Vietnamese snake antivenom (SAV) and Taiwanese Neuro bivalent antivenom (NBAV). The cytotoxins of N. atra (NA-CTX) and N. sumatrana (NS-CTX) were identified as P-type cytotoxins, whereas that of N. kaouthia (NK-CTX) is S-type. All venoms and purified cytotoxins demonstrated varying concentration-dependent cytotoxicity in the following trend: highest for N. atra , followed by N. sumatrana and N. kaouthia . The antivenoms moderately neutralized the cytotoxicity of N. kaouthia venom but were weak against N. atra and N. sumatrana venom cytotoxicity. The neutralization potencies of the antivenoms against the cytotoxins were varied and generally low across NA-CTX, NS-CTX, and NK-CTX, possibly attributed to limited antigenicity of CTXs and/or different formulation of antivenom products. The study underscores the need for antivenom improvement and/or new therapies in treating local tissue toxicity caused by cobra envenomings.

Interpopulation venom variation has been widely documented in snakes across large geographical distances. This variability is known to markedly influence the effectiveness of snakebite therapy, as antivenoms manufactured against one population may not be effective against others. In contrast, the extent of intrapopulation venom variability, especially at finer geographical scales, remains largely uninvestigated. Moreover, given the historical focus on the 'big four' Indian snakes, our understanding of venom variation in medically important yet neglected snakes, such as the monocellate cobra (Naja kaouthia), remains unclear. To address this shortcoming, we investigated N. kaouthia venoms sampled across a small spatial scale (<50 km) in Eastern India. An interdisciplinary approach employed in this study unveiled considerable intrapopulation differences in the venom proteomic composition, pharmacological and biochemical activities, and toxicity profiles. Documentation of stark differences in venoms at such a finer geographical scale, despite the influence of similar ecological and environmental conditions, is intriguing. Furthermore, evaluation of in vitro and in vivo venom recognition and neutralisation potential of Indian polyvalent 'big four' antivenoms and Thai monovalent N. kaouthia antivenom revealed concerning deficiencies. These results highlight the negative impact of phylogenetic divergence and intrapopulation snake venom variation on the effectiveness of conventional antivenom therapy. SIGNIFICANCE: In contrast to our understanding of snake venom variation across large distances, which is theorised to be shaped by disparities in ecology and environment, intrapopulation variation at finer geographic scales remains scarcely investigated. Assessment of intrapopulation venom variability in Naja kaouthia at a small spatial scale (<50 km) in Eastern India unravelled considerable differences in venom compositions, activities and potencies. While the influence of subtle differences in prey preference and local adaptations cannot be ruled out, these findings, perhaps, also emphasise the role of accelerated molecular evolutionary regimes that rapidly introduce variations in evolutionarily younger lineages, such as advanced snakes. The inability of 'big four' Indian antivenoms and Thai N. kaouthia monovalent antivenom in countering these variations highlights the importance of phylogenetic considerations for the development of efficacious snakebite therapy. Thus, we provide valuable insights into the venoms of one of the most medically important yet neglected Indian snakes., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Conservation of sea snakes is virtually nonexistent in Asia, and its role in human-snake interactions in terms of catch, trade, and snakebites as an occupational hazard is mostly unexplored. We collected data on sea snake landings from the Gulf of Thailand, a hotspot for sea snake harvest by squid fishers operating out of the ports of Song Doc and Khanh Hoi, Ca Mau Province, Vietnam. The data were collected during documentation of the steps of the trading process and through interviewers with participants in the trade. Squid vessels return to ports once per lunar synodic cycle and fishers sell snakes to merchants who sort, package, and ship the snakes to various destinations in Vietnam and China for human consumption and as a source of traditional remedies. Annually, 82 t, roughly equal to 225,500 individuals, of live sea snakes are brought to ports. To our knowledge, this rate of harvest constitutes one of the largest venomous snake and marine reptile harvest activities in the world today. Lapemis curtus and Hydrophis cyanocinctus constituted about 85% of the snake biomass, and Acalyptophis peronii, Aipysurus eydouxii, Hydrophis atriceps, H. belcheri, H. lamberti, and H. ornatus made up the remainder. Our results establish a quantitative baseline for characteristics of catch, trade, and uses of sea snakes. Other key observations include the timing of the trade to the lunar cycle, a decline of sea snakes harvested over the study period (approximately 30% decline in mass over 4 years), and the treatment of sea snake bites with rhinoceros horn. Emerging markets in Southeast Asia drive the harvest of venomous sea snakes in the Gulf of Thailand and sea snake bites present a potentially lethal occupational hazard. We call for implementation of monitoring programs to further address the conservation implications of this large-scale marine reptile exploitation., (© 2014 Society for Conservation Biology.)

This study evaluated factors affecting the severity of bite site necrosis and systemic symptoms resulting from envenomation among patients bitten by Thai cobras (Naja kaouthia) in Thailand. We studied 45 victims prospectively. An additional 40 medical records were obtained for a retrospective study. Collected data included gender of the victims, anatomic locations of bites, where attacks took place, and predisposing factors and how they might have affected the clinical course. Most patients were asymptomatic or mildly symptomatic. Neurotoxic symptoms and respiratory failure developed in 31.11% and 12.50% in the prospective and retrospective groups, respectively. Only one patient died, from the effects of prolonged respiratory failure. There was some degree of tissue necrosis at the bite site for almost all victims. One victim required amputation of a digit in the retrospective study, and 33.60% of the prospective group and 20% of the retrospective group required minor surgical debridement. Snakebites in Thailand are still a public health problem, although rapid urbanization has decreased the number of victims because of degradation of the snake's habitat.

Therapeutic antivenom against snakes was first produced by Albert Calmette in 1894. Since then antivenoms have saved the life of countless snakebite victims. However, there are still many problems associated with antivenom production, for example variable percentage of responder horses, low neutralizing potency of antivenom, the large amount of snake venom needed for immunization and the difficulties encountered in producing potent polyvalent antivenoms. These problems have led to shortage and high cost of antivenom and, in some cases, failure of treatment. In 1997, a new immunization protocol for antivenom production was reported. It involves the injection of venom at low dose (approx. 2mg/horse) emulsified in Complete Freund's adjuvant in low volume (0.1-0.2 ml/site) in a total of 10 sites around the neck area of the horse. This immunization protocol has minimized the local reaction at the injection site thus allowing the use of the potent oil adjuvant. This, together with the increase in total surface area of the droplets, allow a more effective immune response to take place, e.g. enhancing the migration and activation of more antigen presenting cells and lymphocytes. The low dose, low volume multi-site immunization has resulted in dramatic improvements on the antivenom production in terms of amount of venom used for immunization, the time required to reach hyperimmune stage, the percent of responder horses and the potency of the antivenom. Furthermore, this protocol has made it possible to produce potent truly polyvalent antivenoms against several elapid and viperid snakes. This immunization protocol has alleviated various problems associated with antivenom production and has implications for immunization in general.

We reviewed a total of 2,525 snakebite patients in Bangkok. Of these, 1,415 were bitten by venomous snakes, 91 by neurotoxic snakes of genus Naja or Bungarus and 1,324 by snakes of family Viperidae or Crotalidae. Seventy-one percent of bites were on the lower extremity. There were two fatal cobra bites; both patients were dead on arrival at the hospital. Bites from vipers caused morbidity but no deaths. Species-specific antivenins are effective in reversing respiratory failure from cobra bites and coagulopathies from bites by Viperidae and Crotalidae snakes. However, early respiratory and wound care will save lives even in the absence of specific cobra and krait antivenin. Care of a snakebite victim should consist of immobilization and bandaging of the bitten limb with elastic bandages during transport to the hospital, early surgical debridement of necrotic tissue, appropriate infusion of antivenin, aggressive respiratory support, management of shock and infection, and peritoneal dialysis or hemodialysis. Incision of bite wounds, suctioning, application of ice, and tourniquets are of no proven value and may be dangerous. All snakebite victims in southeast Asia should survive if they receive early competent care.