METHODOLOGY/PRINCIPLE FINDINGS: In this systematic review, we searched for articles published until May 30, 2022, in PubMed, Scopus, Web of Science, and Embase. Preclinical studies that reported the available antivenoms' neutralizing ability against Asian snake lethality were included. Quality assessment was performed using the Systematic Review Centre for Laboratory animal Experimentation's risk of bias tool and the adapted the Animal Research Reporting In Vivo Experiments guidelines. The availability of effective antivenoms against Asian snakes was analyzed by comparing data from included studies with snakebite-information and data platforms developed by the World Health Organization. Fifty-two studies were included. Most studies assessed the antivenom efficacy against snakes from Southeast Asia (58%), followed by South Asia (35%) and East Asia (19%). Twenty-two (49%) medically important snakes had antivenom(s) with confirmed neutralizing ability. Situation analyses of the availability of effective antivenoms in Asia demonstrated that locally produced antivenoms did not cover all medically important snakes in each country. Among countries without local antivenom production, preclinical studies were conducted only in Bangladesh, Sri Lanka, and Malaysia. Risk of bias assessment was limited in some domains because of unreported data.
CONCLUSIONS/SIGNIFICANCE: Cross-neutralizing of antivenoms against some medically important snakes in Asia was confirmed. This strategy may improve access to geographically effective antivenoms and bypass investment in novel antivenom development, especially in countries without local antivenom production. A database should be developed to aid the development of a snakebite-information system.
MATERIALS AND METHODS: Snakebite patients were prospectively recruited between 2017 and 2019. All patients were examined with POCUS to locate edema and directly visualize and measure the arterial flow in the compressed artery. The presence of DRAF in the compressed artery is suggestive of ACS development because when compartment space restriction occurs, increased retrograde arterial flow is observed in the artery.
RESULTS: Twenty-seven snakebite patients were analyzed. Seventeen patients (63%) were bitten by Crotalinae snakes, seven (26%) by Colubridae, one (4%) by Elapidae, and two (7%) had unidentified snakebites. All Crotalinae bit patients received antivenom, had subcutaneous edema and lacked DRAF in a POCUS examination series.
DISCUSSION: POCUS facilitates clinical decisions for snakebite envenomation. We also highlighted that the anatomic site of the snakebite is an important factor affecting the prognosis of the wounds. There were limitations of this study, including a small number of patients and no comparison with the generally accepted invasive evaluation for ACS.
CONCLUSIONS: We are unable to state that POCUS is a valid surrogate measurement of ACS from this study but see this as a starting point to develop further research in this area. Further study will be needed to better define the utility of POCUS in patients envenomated by snakes throughout the world.
METHODS: This study examined the immunological binding and neutralization capacity of PCAV against the two cobra venoms using WHO-recommended protocols.
RESULTS: In mice, both venoms were highly neurotoxic and lethal with a median lethal dose of 0.18 and 0.20 µg/g, respectively. PCAV exhibited strong and comparable immunoreactivity toward the venoms, indicating conserved venom antigenicity between the two allopatric species. In in vivo assay, PCAV was only moderately effective in neutralizing the toxicity of both venoms. Its potency was even lower against the hetero-specific N. samarensis venom by approximately two-fold compared with its potency against N. philippinensis venom.
CONCLUSION: The results indicated that PCAV could be used to treat N. samarensis envenomation but at a higher dose, which might increase the risk of hypersensitivity and worsen the shortage of antivenom supply in the field. Antivenom manufacturing should be improved by developing a low-dose, high-efficacy product against cobra envenomation.