Clinic: Trimeresurus sp. and Craspedocephalus sp., Protobothrops sp., Tropidolaemus sp., Ovophis sp.

Examine for venom effects

(Autopharmacological effects)

• Nausea, vomiting
• Sweating
• Urticaria, angiooedema
• Arterial hypotension / hypovolaemic shock (transient, recurrent; immediate; delayed (CLS))
• Diarrhoea
• Bronchospasm 

Local Effects

• Pain
• Tender local (spreading) swelling
• Blistering
• Lymphangiopathy and lymphadenopathy
• Necrotic skin

Haematological effects 

• Clotting disturbances:
  • Bleeding from the fang marks and from injuries, in particular ones that are not located in the region in which venom application occurred.
  • Bleeding into the skin (ecchymosis, petechiae)
  • Gingival bleeding, bleeding from the nose, conjunctiva, haematemeis, bleeding per rectum, including melaena, haematuria, haemoptysis.
  • Oliguria, anuria (VICC / AKI)
• Bleeding and/or haemolytic anaemia:
  • Arterial hypotension (haemorrhagic shock)
  • Acute abdomen (intra-abdominal bleeding!)
  • Loin pain/renal bed sensitive to percussion (ischaemia, renal haemorrhage!)
  • Local neurological signs, meningism, coma (intracranial bleeding!)
  • Pale sclera
  • Oliguria, anuria (arterial hypotension / AKI)

Renal effects

• Acute kidney injury:
  • Loin pain (lower back pain)
  • Renal bed sensitive to percussion
  • Haematuria, haemoglobinuria, myoglobinuria
  • Oliguria (< 400 ml of urine / 24 h), anuria
  • Uraemia (nausea, acidotic breathing, hiccups, pleuritic chest pain, encephalopathy) 

Species-specific envenoming pattern

The assessment of the envenoming pattern is based on the data from publication in which the identification of the snakes is clearly specified and in accordance with accepted criteria.

Morphological similarity is a challenge for species identification impacting on reporting of confirmed species-specific features of envenoming.

¹Autopharmacological effects suspected Hutton et al. (1990)

² Renal failure secondary in the context of shock or a haemostatic defect. Primary nephrotoxic effect of the venom? (Hutton et al 1990).

Thein et al. (2021) report AKI in 21/333 patients, but only one required dialysis. At least 10/21 of the cases with AKI in this study were more likely to represent bites from Trimeresurus sp. than Dabois siamensis because the snake responsible was brought into the hospital, examined and described by the treating physician as “green-coloured”.

One case of AKI from envenoming by Trimeresurus erythrurus. A review of cases of AKI following bites by Trimeresurus erythrurus and Trimeresurus albolabris in Myanmar confirms that, at least on rare occasions, Trimeresurus sp. envenoming can cause AKI. This is of importance for snakebite management in Myanmar as local swelling, coagulopathy and AKI is generally considered pathognomonic of Daboia siamensis envenoming. 

³Acute renal impairment (secondary? / primary?) (Yeh et al. 2018). 

Trimeresurus sp. (incl. Craspedocephalus sp., Protobothrops sp., Tropidolaemus sp., Ovophis sp.)

India

Thakur et al (2024) report broadly on green pit viper envenoming in India and point out that green pit vipers are one of the most widely distributed group of venomous snakes in south-east Asia. High morphological similarity is a challenge for species identification.

Malaysia

Qamruddin et al (2023) report very broadly on pit viper envenoming in Malaysia, including Trimeresurus sp..

Myanmar

Thein et al (2021) report on 355 bites by a witnessed, green-coloured snake in Myanmar. In 22 cases morphological identification of which 21 were Trimeresurus albolabris, and one an Asian vine snake, Ahaetulla prasina which is not of medical importance (see also Trimeresurus albolabris below).

Nepal

Bhatt et al (2020) report one case of a mountain pit viper (Ovophis monticola) and 14 cases of green pit vipers with coagulopathy from Himalayan regions of Nepal; all morphologically confirmed.

Vietnam

Blessmann et (2018) report on snakebite in central Vietnam including Trimeresurus sp. as one of the main culprits of snakebite in the area.

Clinical management

See also (depending on the origin of the culprit)

Clinical Management: Far East

Clinical Management: Indian Subcontinent and Southeast Asia

for advice on post-First Aid measures, diagnosis (clinical, laboratory) and treatment (supportive, antivenom).

First Aid

Release of any type of tourniquet follow links above.

Local treatment

Pain control
Tetanus prophylaxis
Standard wound care
Necroses: debridement; split-thickness skin grafting
Systemic antibiotics: standard indications
WHO (2010, 2016) 

Systemic supportive treatment

A general understanding of emergency medicine is required, or can be found in emergency medicine guidelines, e.g. ABCDE approach, WHO-ICRC Basic Emergency Care.

Follow SAMPLE & ABCDE ApproAch

• Comprehensive ABCDE approach

• ICRC Basic Emergency Care: approach to the acutely ill and injured (SAMPLE  and ABCDE approach: first module)

Obey Trimeresurus sp. (incl. Craspedocephalus sp., Protobothrops sp., Tropidolaemus sp., Ovophis sp.) -  specific features

see 

• 'Species-specific envenoming pattern' above

and

• Guidelines for the Management of Snakebites, WHO Regional Office SE Asia

Key issues

See footnotes above.

Specific treatment (antivenoms)

• WHO Snakebite Information and Data Platform
• Guidelines for the Management of Snakebites, WHO Regional Office SE Asia

References

• Bhatt N, Singh A, Sharma SK. Case Report: Management of Pit Viper Envenoming without Antivenom: A Case Series. Am J Trop Med Hyg. 2020 Jun;102(6):1440-1442. PMCID: PMC7253110. https://doi.org/10.4269/ajtmh.20-0035
• Blessmann J, Nguyen TPN, Bui TPA, Krumkamp R, Vo VT, Nguyen HL. Incidence of snakebites in 3 different geographic regions in Thua Thien Hue province, central Vietnam: Green pit vipers and cobras cause the majority of bites. Toxicon. 2018 Dec 15;156:61-65. doi: 10.1016/j.toxicon.2018.11.009. Epub 2018 Nov 15. PMID: 30448540. https://doi.org/10.1016/j.toxicon.2018.11.009
• Qamruddin RM, Safferi RS, Mohamed Ismail Z, Salleh MS, Abd Hamid MNH, Frederic Ng VER, Goh WC, Ismail AK. Frequency, geographical distribution and outcomes of pit viper bites in Malaysia consulted to Remote Envenomation Consultancy Services (RECS) from 2017 to 2020.PLoS Negl Trop Dis. 2023 Aug 16;17(8):e0011569. PMID: 37585486; PMCID: PMC10461839. https://doi.org/10.1371/journal.pntd.0011569
• Thakur S, Giri S, Lalremsanga HT, Doley R. Indian green pit vipers: A lesser-known snake group of north-east India. Toxicon. 2024 May 6;242:107689. Epub 2024 Mar 24. PMID: 38531479. https://doi.org/10.1016/j.toxicon.2024.107689
• Thein MM, Rogers CA, White J, Mahmood MA, Weinstein SA, Nwe MT, Thwin KT, Zaw A, Thant M, Oo SSL, Gyi KM, Warrell DA, Alfred S, Peh CA. Characteristics and significance of "green snake" bites in Myanmar, especially by the pit vipers Trimeresurus albolabris and Trimeresurus erythrurus. Toxicon. 2021 Nov;203:66-73. Epub 2021 Sep 22. PMID: 34562496. https://doi.org/10.1016/j.toxicon.2021.09.008 

Species-specific evidence

Trimeresurus sp.

Trimeresurus albolabris

 Thailand

• Hutton et al. (1990) (Case reports and review of the literature)
  24 bites; identification: morphological or identification from specific venom antigen in the serum or tissue fluid aspirate by ELISA according to the methods described by Ho et al. (1986a) and Silamut et al. (1987).

Myanmar

• Thein et al. (2021)
  21 bites;identification: morphological.

Captive (“pet”) snakes

• Greene et al. (2017)
  1 bite in a snake keeper in the US; identification morphological.
  
  Signs & symptoms 
  Autopharmacological effects
  Shock 1/24 (Hutton et al. 1990). The patient had already been hospitalised 1.75 h after the bite and there was no indication of systemic bleeding, which makes it likely that the cause of the shock was an autopharmacological reaction.
  Local effects
  Swelling that extended over >1/2 of the extremity in 46% of patients and an average increase of 14.8% in the bitten extremity compared to the healthy extremity. Painful swelling of local lymph nodes in 46% of patients. Local blistering in 25% of patients. Necroses 2/24, in both cases involving fingers (Hutton et al. 1990).
  Swelling of the bitten limb 15/21. None developed necrosis or blistering (Thein et al. 2021).
  Haematological effects
  Local ecchymoses in 58% of patients; petechial haemorrhages 2/24; epistaxis 1/24; hypovolaemic shock 1/24 (the patient was first hospitalised 24 h after the bite and was bleeding, which makes it probable that the shock was due to hypovolaemia); menorrhagia 1/24 (Hutton et al. 1990).
  Coagulopathy 3/21, defined as a positive 20-min whole blood clotting test (20WBCT). thrombocytopenia 0/21 (Thein et al. 2021).
  See also “Laboratory and physical investigations  - Haemostasis” below.
  Renal effects
  Secondary in the context of shock or a haemostatic defect. Primary nephrotoxic effect of the venom?
  Acute kidney injury 0/21 (Thein et al. 2021).

Trimeresurus erythrurus

Burma

• Tin-Nu-Swe, personal communication cited in: Hutton et al. (1990).
  
  Signs & symptoms 
  Local effects
  Swelling (Tin-Nu-Swe, pers. comm. cited in: Hutton et al. (1990).

Trimeresurus kanburiensis

Thailand

• Warrell et al. (1992)
  1 case; identification: morphological.
  
  Signs & symptoms
  Local effects
  Very strong pain at the site of the bite that spread with the swelling. Massive swelling, at a maximum on the 3rd day, when it extended from the right foot as far as and including the right flank (increase in circumference approx. 20%) (Warrell et al. 1992).
  Hypovolaemic shock. The patient had her first episode of hypotension, tachycardia, sweating etc. 19 h after the bite, and further episodes after that, accompanied by increasing extensive local swelling with ecchymoses as well as a decrease in haemoglobin. Volume replacement was successful. Clinical findings and the success of the treatment make it probable that hypovolaemia was the cause of the state of shock (Warrell et al. 1992).
  Haematological effects
  Ecchymoses (Warrell et al. 1992).
  See also “Laboratory and physical investigations  - Haemostasis” below.

Trimeresurus macrops

Thailand

• Hutton et al. (1990) (Case reports and review of the literature)
  5 T. macrops (=T. (Trimeresurus) macrops) bites; identification: morphological or identification from specific venom antigen in the serum or tissue fluid aspirate by ELISA according to the methods described by Ho et al. (1986a) and Silamut et al. (1987).
• Viravan et al. (1992)
  12 cases ; identification: morphological.
  
  Signs & symptoms 
  Local effects
  Swelling that extended over <1/2 the extremity, 5/5 (Hutton et al. 1990).
  Mild local swelling (Viravan et al. 1992).
  See also “Laboratory and physical investigations  - Haemostasis” below.

Trimeresurus popeorum

• Visudhiphan et al (1989)
  51 patients

Trimeresurus purpureomaculatus

Malaysia

• Reid (1968)
  28 bites; identification:confirmed.

Thailand

• Viravan et al. (1992)
  3 cases ; identification: morphological.
  
  Signs & symptoms 
  Local effects
  Local swelling 15/28, 2 of whom had necrosis (Reid 1968).
  Mild / no local swelling (Viravan et al. 1992).
  See also “Laboratory and physical investigations  - Haemostasis” below.

Trimeresurus stejnegeri

Taiwan

• Chen et al. (2022)
  1 case ; identification: morphological
• Mao et al. (2024)
  1 case and review.
  
  Signs & symptoms 
  Local effects
  Swelling above the ankle. (Chen et al. 2022)
  Rapid onset of local swelling and pain; ecchymosis; bullae or blisters in some cases. Lymphangitis and lymphadenitis.
  Develop within hours of the bite and can spread beyond the affected limb, extending into the trunk (Mao et al. 2024).
  See also “Laboratory and physical investigations  - Haemostasis” below.

Trimeresurus venustus

Captive (“pet”) snakes

• Fuchs et al. (2019)
  1 case published and additional 2 cases unpublished cases reported; identification morphological.
  Signs & symptoms 
  Local effects
  Swelling, reddish-blueish discoloration and moderate pain at the bite site (5 minutes after the bite). Whole hand was swollen and axillary lymph nodes painful (50 minutes after the bite) Fuchs et al. (2019).

Craspedocephalus sp.

Craspedocephalus malabaricus (formerlyTrimeresurus malabaricus)

India (Western Ghats)

• Sirur et al. (2022)
  1 case; identification: morphological.
  
  Signs & symptoms 
  Local effects
  Swelling of the face (bite in the face) (Sirur et al. 2022).
  See also “Laboratory and physical investigations  - Haemostasis” below.

Craspedocephalus macrolepis (formerlyTrimeresurus macrolepis)

South India

• Whitaker (1972) 
  18 bites attributed to T. macrolepis (=Craspedocephalus macrolepis); identification: criteria not specified.
  
  Signs & symptoms 
  Local effects
  Burning pain. Swelling of the entire extremity (Whitaker 1972).

Craspedocephalus trigonocephalus (formerlyTrimeresurus trigonocephalus)

Sri Lanka

• Namal Rathnayaka et al. (2017a)
  3 bites; identification: 1 morphological; 2 patients’ observation and recognition on colour charts.
• Namal Rathnayaka et al. (2017b)
  17 bites; identification: 10 morphological; 7 patients’ observation and recognition on colour charts.
  
  Signs & symptoms 
  Local effects
  Severe pain at the bite site; extensive local swelling (Namal Rathnayaka et al. 2017a).
  Mild to severe pain at the bite site; mild to severe local swelling(Namal Rathnayaka et.al. 2017b).
  Haematological effects
  6/17 patients bleeding from the bite site (NamalRathnayaka et al. 2017b).
  See also “Laboratory and physical investigations  - Haemostasis” below.

Protobothrops sp.

Protobothrops elegans (formerlyTrimeresurus elegans)

Japan

• Sawai et al. (1971a, 1972)
  287 bites; identification: geographical exclusion: Trimeresurus elegans (=Protobothrops elegans) is only found on the Yaeyama Islands.
  
  Signs & symptoms
  Local effects
  Of 287 bites, necroses in only a few cases, apparently with no long-term sequelae (deformities etc.) (Sawai et al. 1971, 1972).

Protobothrops flavoviridis (formerlyTrimeresurus flavoviridis)

Japan

• Hifumi et al. (2015) 
  Review
  
  Signs & symptoms
  Local effects
  Swelling within 30 min. (Hifumi et a.l 2015).
  Hypotension (due to extensive swelling?) (Hifumi et al. 2015).

Protobothrops mucrosqamatus (formerlyTrimeresurus mucrosquamatus)

Taiwan

• Mao et al. (2024)
  1 case and review.
• Yeh et al. (2018)
  2 cases; identification: ? morphological, 1 patient identification by patient on picture chart.
  
  Signs & symptoms 
  Local effect
  Local pain; progressive (severe) soft tissue swelling (Mao et al. 2024).
  Local pain; progressive (severe) soft tissue swelling (Yeh et al. 2018).
  Renal effects
  Acute renal impairment (secondary? / primary?) (Yeh et al. 2018).

Tropidolaemus sp.

Tropidolaemus wagleri (formerlyTrimeresurus wagleri)

Malaysia

• Reid (1968)
  48 bites; Identification:confirmed
• Viravan et al. (1992)
  2 cases ; identification: morphological.
  
  Signs & symptoms
  Local effects
  Local swelling 24/48, 1 of whom had necrosis (Reid 1968).
  Mild / nolocal swelling (Viravan et al. 1992).

Ovophis sp.

Ovophis monitcola

India, Nagaland

• Ralph et al. (2023)
  1 bite; identification: morphological

Nepal

• Bhatt et al. (2020)
  1 bite; identification: morphological
  
  Signs & symptoms
  Local effects
  Sharp pain, swellingextending over 72 hrs. into the right groin and gluteal region (Ralph et al. 2023)
  Pain and swelling over the whole right leg (Bhatt et al. 2020).
  See also “Laboratory and physical investigations  - Haemostasis” below.

Laboratory and physical investigations

Haemostasis
Type of haemostatic defect 

Trimeresuris sp.

Trimeresurus albolabris
Defibrin(ogen)ation ("thrombin-like" activity, little effect on other clotting factors) with reactive fibrinolysis. Platelet function unaffected (Hutton et al. 1990).
Trimeresurus kanburiensis
Defibrin(ogen)ation with reactive fibrinolysis (Warrell et al. 1992).

Ovophis sp.
Defibrination syndrome likely (Ralph et al. 2023).

Clinically observed haemostatic defect

Trimeresuris sp.

Trimeresurus albolabris: common, sometimes with a long delay (Hutton et al. 1990, Viravan et al. 1992).

Trimeresurus erythrurus: not observed (Tin-Nu-Swe, personal communication cited in: Hutton et al. 1990)

Trimeresurus kanburiensis: does occur (Warrell et al. 1992).

Trimeresurus macrops: not observed (Hutton et al. 1990, Viravan et al. 1992).

Trimeresurus popeorum (Visudhiphan et al. 1989).

Trimeresurus purpureomaculatus: ? bleeding (Reid 1968).
Trimeresurus stejnegeri: not observed(Chen et al. 2022, Chiang et al. 2020, Mao et al. 2024).

Trimeresurus venustus: not observed (Fuchs et al 2019).

Craspedocephalus sp.

Craspedocephalus macrolepis (described as Trimeresurus macrolepis): not observed (Whitaker 1972).

Craspedocephalus malabaricus (formerly Trimeresurus malabaricus): not observed (Sirur et al. 2022).

Craspedocephalus trigonocephalus (formerly Trimeresurus trigonocephalus): bleeding from the bite site (Namal Rathnayaka et al. 2017 b).

Protobothrops sp.

Protobothrops elegans (formerly Trimeresurus elegans): ?
Protobothrops flavoviridis (formerly Trimeresurus flavoviridis): ?
Protobothrops mucrosqamatus (formerly Trimeresurus mucrosquamatus): not observed (Mao et al. 2024, Yeh et al. 2018).

Tropidolaemus sp.

Tropidolaemus wagleri (formerly Trimeresurus wagleri): not observed (Reid 1968).

Ovophis sp.

Ovophis monticola: not observed (Bhatt et al. 2020, Ralph et al. 2023).

References

• Bhatt N, Singh A, Sharma SK. Case Report: Management of Pit Viper Envenoming without Antivenom: A Case Series. Am J Trop Med Hyg. 2020 Jun;102(6):1440-1442. PMCID: PMC7253110. https://doi.org/10.4269/ajtmh.20-0035
• Chen YH, Mao YC, Liu PY, Chiang LC, Chen WY, Lai CS, Ho CH, Chen KT, Lin WL, Wen CY. Uncommon defibrinogenation and coagulopathy caused by Trimeresurus stejnegeri stejnegeri envenomation in a patient with swelling above the ankle. Toxicon. 2022 Oct 15;217:143-147. Epub 2022 Aug 18. PMID: 35987354. https://doi.org/10.1016/j.toxicon.2022.08.011
• Chiang LC, Tsai WJ, Liu PY, Ho CH, Su HY, Lai CS, Lai KL, Lin WL, Lee CH, Yang YY, Doan UV, Maharani T, Mao YC. Envenomation by Trimeresurus stejnegeri stejnegeri: clinical manifestations, treatment and associated factors for wound necrosis. J Venom Anim Toxins Incl Trop Dis. 2020 Sep 18;26:e20200043. PMID: 32983233; PMCID: PMC7500479. https://doi.org/10.1590/1678-9199-JVATITD-2020-0043
• Fuchs J, Bessire K, Weiler S. A confirmed bite by a Beautiful Pit Viper (Trimeresurus venustus) resulting in local symptoms. Toxicon. 2019 May;163:44-47. Epub 2019 Mar 20. PMID: 30902684. https://doi.org/10.1016/j.toxicon.2019.03.019

• Greene S, Galdamez LA, Tomasheski R. White-Lipped Tree Viper (Cryptelytrops albolabris) Envenomation in an American Viper Keeper.J Emerg Med. 2017 Dec;53(6):e115-e118. Epub 2017 Nov 6. PMID: 29102099. https://doi.org/10.1016/j.jemermed.2017.09.003 

• Hifumi T, Sakai A, Kondo Y, Yamamoto A, Morine N, Ato M, Shibayama K, Umezawa K, Kiriu N, Kato H, Koido Y, Inoue J, Kawakita K, Kuroda Y. Venomous snake bites: clinical diagnosis and treatment. J Intensive Care. 2015 Apr 1;3(1):16. PMID: 25866646; PMCID: PMC4393627. https://doi.org/10.1186/s40560-015-0081-8

• Hutton RA, Looareesuwan S, Ho M, Silamut K, Chanthavanich P, Karbwang J, Supanaranond W, Vejcho S, Viravan C, Phillips RE, et al. Arboreal green pit vipers (genus Trimeresurus) of South-East Asia: bites by T. albolabris and T. macrops in Thailand and a review of the literature. Trans R Soc Trop Med Hyg. 1990 Nov-Dec;84(6):866-74. PMID: 2096527. https://doi.org/10.1016/0035-9203(90)90111-q

• Mao YC, Liu PY, Lai KL, Luo Y, Chen KT, Lai CS. Clinical Characteristics of Snakebite Envenomings in Taiwan. Toxins (Basel). 2024 Dec 30;17(1):14. PMID: 39852967; PMCID: PMC11769513. https://doi.org/10.3390/toxins17010014
• Namal Rathnayaka RM, Kularatne SA, Ranathunga PE. Coagulopathy and extensive local swelling following Green pit viper (Trimeresurus trigonocephalus) envenoming in Sri Lanka. Toxicon. 2017a Apr;129:95-99. Epub 2017 Feb 16. PMID: 28216410. https://doi.org/10.1016/j.toxicon.2017.02.011
• Namal Rathnayaka RMMK, Ranathunga PEAN, Kularatne SAM. Epidemiology and clinical features of Green pit viper (Trimeresurus trigonocephalus) envenoming in Sri Lanka. Toxicon. 2017b Oct;137:99-105. Epub 2017 Jul 21. PMID: 28735968. https://doi.org/10.1016/j.toxicon.2017.07.017
• Ralph R, Garg D, Balachandran A, Ganesh SR, Lamb T. A case report of Ovophis monitcola (Mountain pit-viper) envenoming in northeastern India resulting in prolonged coagulopathy. Toxicon. 2023 Jun 15;229:107147. Epub 2023 Apr 29. PMID: 37127123. https://doi.org/10.1016/j.toxicon.2023.107147
• Reid, H. A. (1968) Symptomatology, pathology, and treatment of land snake bite in India and Southeast Asia. In Bücherl, W., E. E. Buckley, V. Deulofen (ed.): Venomous animals and their venoms, Vol. 1. Academic Press, New York: 611-642

• Sawai, Y., Y. Kawamura, T. Fukuyama, H. Chinzei (1971) Snakebites on the Amami and Ryukyu islands in 1969.Snake 3: 1-8

• Sawai, Y., T. Fukuyama, Y. Kawamura, H. Chinzei, T. Yamaguchi (1972) Snakebites in the Amami and Ryukyu Islands in 1970.Snake 4: 89

• Thein MM, Rogers CA, White J, Mahmood MA, Weinstein SA, Nwe MT, Thwin KT, Zaw A, Thant M, Oo SSL, Gyi KM, Warrell DA, Alfred S, Peh CA. Characteristics and significance of "green snake" bites in Myanmar, especially by the pit vipers Trimeresurus albolabris and Trimeresurus erythrurus. Toxicon. 2021 Nov;203:66-73. Epub 2021 Sep 22. PMID: 34562496. https://doi.org/10.1016/j.toxicon.2021.09.008
• Viravan C, Looareesuwan S, Kosakarn W, Wuthiekanun V, McCarthy CJ, Stimson AF, Bunnag D, Harinasuta T, Warrell DA. A national hospital-based survey of snakes responsible for bites in Thailand. Trans R Soc Trop Med Hyg. 1992 Jan-Feb;86(1):100-6. PMID: 1566285. https://doi.org/10.1016/0035-9203(92)90463-m
• Visudhiphan S, Tonmukayakul A, Tumliang S, Dumavibhat B, Piankijagum A. Dark green pit viper (Trimeresurus popeorum) bite: clinical and serial coagulation profiles in 51 cases. Am J Trop Med Hyg. 1989 Nov;41(5):570-5. PMID: 2817213. https://doi.org/10.4269/ajtmh.1989.41.570
• Warrell DA, Looareesuwan S, Stimson AF, Hutton RA. Rediscovery and redefinition of Malcolm Smith's Trimeresurus kanburiensis in Thailand, with a report of envenoming. Trans R Soc Trop Med Hyg. 1992 Jan-Feb;86(1):95-9. PMID: 1566323. https://doi.org/10.1016/0035-9203(92)90461-k
• Whitaker, R. (1972) Pit viper Trimeresurus macrolepis (Beddome) bites at a South Indian tea estate. J. Bombay nat. Hist. Soc. 70: 207-208
• Yeh YT, Chen MH, Chang JC, Fan JS, Yen DH, Chen YC. Protobothrops mucrosquamatus Bites to the Head: Clinical Spectrum from Case Series. Am J Trop Med Hyg. 2018 Sep;99(3):753-755. Epub 2018 Jun 21. PMID: 29943718; PMCID: PMC6169154. https://doi.org/10.4269/ajtmh.18-0220