CPG Revision: Approach to Snakebite in Asia

The CPG revision approaches snakebite management in Asia by prioritizing coverage against highest threat species causing the most bites and the species which are most likely to cause severe injury and death. We have selected antivenoms with favorable efficacy, safety, and sourcing that give the broadest species coverage with the fewest possible products. Taking the species and the antivenoms into account, we have subdivided Asia into the following regions: 1) Southeast Asia, 2) Southeast China/Northern Laos/Northern Vietnam, 3) Taiwan, 4) Japan, and 5) Korean Peninsula/Northeast China.

Venomous Asian snakes fall into 2 broad categories, elapids (primarily neurotoxic), and vipers (primarily hemotoxic/cytotoxic). Exceptions exist, however, and the most notable is that several Asian cobras (elapids) cause primarily cytotoxic effects with minimal neurotoxicity. Other Asian cobras, however, are severely neurotoxic. The available neuro antivenom products, such as Thai Red Cross Neuro Polyvalent (TRC-NPAV), and Taiwan Neuro Polyvalent (NIPM-NBB) are indicated for both neurotoxic and cytotoxic cobra syndromes. The primary clinical implication of this is that a patient presenting with a neurotoxic bite or a cytotoxic cobra bite (severe pain, signs of tissue damage, absence of hemorrhage) should receive a neuro polyvalent antivenom. In general, the Thai polyvalent antivenoms provide excellent coverage for most of the venomous snakes found in SE Asia (Thailand, Myanmar, Cambodia, Laos, Vietnam, Malaysia, Indonesia, and Brunei). As such, monovalent antivenoms are not needed in this region.

CPG Revision: East Asia (China, Japan, Korean Peninsula, Borders)

SE China, Northern Laos, and Northern Vietnam:

The venomous snake fauna in this region is very similar to Taiwan. A notable exception is the presence of the king cobra in China and adjacent southern countries. King cobras are large elapids that produce a mixed clinical syndrome of severe neurotoxicity (main life threat) and cytotoxic tissue damage; which is covered by TRC-NPAV. The Thai polyvalent antivenoms are indicated in this region but notably do not cover other important snakes like the Habu (Protobothrops) and the Sharp-nosed viper (Deinagkistrodon). These special cases are addressed with the Taiwan antivenoms (NIPM-PTBV and NIPM-SNV) in the algorithm.

Japan, Korean Peninsula, NE China:

The venomous snakes of Japan, the Korean Peninsula, and NE China are similar and vipers like the Mamushi (Gloydius spp.) predominate.^284-292 Japanese and Korean antivenoms provide good coverage for these snakes. An exception is the Okinawa region and adjacent smaller southern Japanese islands, where the Habu (Protobothrops) is found.²⁸³ This is also addressed in the algorithm with Japanese Habu antivenom (CSTRI-HABU).

Sea Snake Envenomation:

Finally, sea snakes are present throughout the Indo-Pacific region in oceans and aquatic coastal regions. These snakes can produce severe neurotoxic effects. Bites are extremely rare from sea snakes and usually only occur to fishermen removing the snakes from their nets. Australia produces the only antivenom for sea snakes (CSL-SS) and this is reflected as a special case in the algorithm. In cases where the clinical envenomation syndrome is unclear and/or the culprit snake is in question, the clinician should contact the DOD Advisor Line.