The fast and confident identification of medically important snakes could affect early intervention in snakebite management, however, in any uncertain instances, medical doctors are advised to seek expert assistance for the identification of the snake.

These observations and recommendations were made in a perspective on "Minimising the misidentification of common medically important snakes of Sri Lanka in the hospital setting" which was authored by A. Silva (attached to the Rajarata University's Medicine and Allied Sciences Faculty, and the Monash University's Medicine, Nursing and Health Sciences Faculty's Monash Venom Group), T. de Alwis and S. Wijesekara (both attached to the Wild Island Foundation in Moratuwa and the Colombo University's Medical Faculty), and R. Somaweera (attached to the Stantec in Australia and the Western Australian University's Biological Sciences School) and published in the Anuradhapura Medical Journal's 17th Volume's Second Issue in July, 2023.

Snakebites, per the 2020 Annual Health Bulletin, are a significant public health issue in Sri Lanka, with over 30,000 snakebite victims annually admitted to Government hospitals. S. Bandara's "Number of snake species" mentions that the Island has a rich diversity of reptiles, which includes 108 species of snakes, inland as well as in the coastal waters. However, per A. Silva's "Snakebites and snake envenomings" and "Dangerous snakes, deadly snakes and medically important snakes", only five species of snakes, namely, the Russell’s viper (Daboia russelii), the Merrem’s hump nosed pit viper (Hypnale hypnale), the Indian or common krait (Bungarus caeruleus), the Sri Lankan cobra (Naja polyocellata) and the saw scaled viper (Echis carinatus) are considered as snakes of the highest medical importance due to the frequency and severity of their bites and envenomings. According to "Estimates of the disease burden due to land snake bites in Sri Lankan hospitals" by A. Kasturiratne, A. Pathmeswaran, M.M.D. Fonseka, D.G. Lalloo, S. Brooker and H.J. de Silva, 35%-45% of hospital admissions in Sri Lanka are due to the Merrem’s hump nosed pit viper bites while 30%-40% are due to the Russell’s viper bites, while the remaining one third of the bites are caused by the Indian krait, the Sri Lankan cobra, the saw scaled vipers, and other snakes with lesser medical importance or no medical importance. 

Sri Lanka currently uses Indian polyvalent antivenom that is developed against the Russell’s viper, the Indian common cobra, the saw scaled vipers and Indian krait venoms. Commercial monovalent antivenoms are not available in Sri Lanka. According to "Hump nosed pit viper envenoming causes mild coagulopathy with incomplete clotting factor consumption" by K. Maduwage, F.E. Scorgie, A. Silva, S. Shahmy, F. Mohamed, C. Abeysinghe, H. Karunathilake, L.F. Lincz, C.A. Gnanathasan and G.K. Isbister, "Epidemiology and the clinical effects of hump nosed pit viper envenoming in Sri Lanka" by K. Maduwage, G.K. Isbister, A. Silva, S. Bowatta, S. Mendis and I. Gawarammana, and the Sri Lanka Medical Association's Snakebite Expert Committee's "Guidelines for the management of snakebites in hospital", although Merrem’s hump nosed pit viper envenoming frequently causes venom induced consumption coagulopathy and acute kidney injury, it is not covered by the Indian polyvalent antivenom and hence is not recommended. I. Gawarammana and D.E. Keyler's "Dealing with adverse reactions to snake antivenom" notes that Indian polyvalent antivenom frequently leads to severe acute adverse reactions. 

Therefore, the decision to give antivenom should be carefully made by selecting those who require antivenom by authenticating the identity of the snake. In addition, A. Silva, D. Gamlaksha and D. Waidyaratne's "Medico-legal significance of the identification of the offending snake in a fatal snakebite: A case report" and "Bites by snakes of lesser medical importance in a cohort of snakebite patients from rural Sri Lanka" by S. Thalgaspitiya, G. Isbister, K. Ukuwela, C. Sarathchandra, H. Senanayake, N. Lokunarangoda, S. Siribaddana and A. Silva, observe that several species of non-venomous snakes are closely similar in colouration to medically important snakes such as kraits (the Bungarus species), thus potentially causing confusion in snakebite management. 

Many snakebite victims present to the hospital with the offending snake specimen or its pieces, so as to assist in the management of the snakebite. "Victims' response to the snakebite and the socio-epidemiological factors of 1,018 snakebites in a tertiary care hospital in Sri Lanka" by A.M. Kularatne, A. Silva, K. Maduwage, I. Ratnayake, C. Walathara, C. Ratnayake, S. Mendis and R. Parangama, found that the percentage of patients bringing the snake to the hospital could be as high as 46% in parts of Sri Lanka. Additionally, patients or people admitting them could have images of the snake responsible for the bite. 

Therefore, knowledge of the accurate identification of the offending snake specimen, when available, could lead to early and improved treatment and the management of snakebites in Sri Lanka.

Given the frequency of snakebites presented to Sri Lankan healthcare settings, medical doctors are expected to confidently identify medically important snakes and distinguish them from the rest of the snakes. It is not a challenging task because medically important snakes are far and few compared to the vast majority of snakes that have no medical importance. Medically important snakes in Sri Lanka are morphologically quite distinguishable from each other, as well as from snakes that have no medical importance, and the unique distribution patterns of certain medically important snakes make their bites only occur in specific geographical areas of Sri Lanka.

However, the identification keys and resources developed for identifying medically important snakes for medical doctors might be practically inconvenient in a busy setting because they include several steps of morphological examination of the specimens or are cluttered with non-relevant information or other species. Further, most of the snake specimens that patients bring to the hospital are often severely damaged, hence, the application of the identification keys that are designed to identify a complete, undamaged specimen might not be practically useful. Therefore, the ability to identify the relevant species of snake from multiple features is important.

There are six viperid snakes present in Sri Lanka, namely, the Russell’s viper, the saw scaled viper, three species of hump nosed pit vipers (H. hypnale, H. nepa and H. zara) and the green pit viper (Peltopelor trigonocephalus). These snakes possess ‘viperine’ bodies, which are short and robust, and with triangular heads and prominent necks (viper-like bodies), that can be easily distinguishable from other forms. Their tails are notably short. However, juvenile pythons (Python molurus) have a relatively short and robust body, hence are often misidentified as the Russell’s viper. Identifying vipers to the species level is highly important in a hospital setting because two thirds of all snakebites admitted to Sri Lankan hospitals are viperine bites, all six of the local species are medically important, and the administration of antivenom is recommended for only the Russell’s viper's and the saw scaled viper's bites. Although the distributions of the viperids in the country generally do not overlap, K. Maduwage, A. Silva, K. Manamendra-Arachchi and R. Pethiyagoda's "A taxonomic revision of the South Asian hump nosed pit vipers (Squamata: Viperidae: Hypnale)" points out that the three species of hump nosed pit vipers morphologically closely resemble each other so as do their effects of envenoming and management. Therefore, distinguishing them at the hospital by a medical officer is not required. Hence, they are treated together as ‘hump nosed pit vipers’. With regard to patient management, the most important differentiation is of the Russell’s viper, especially their juveniles, from hump nosed pit vipers. Hump nosed pit vipers are widespread in the country and cause the most number of medically important snakebites in Sri Lanka. Distinguishing the envenoming caused by these snakes based on clinical grounds is challenging at times. "Neurotoxicity in Russell's viper envenoming in Sri Lanka: A clinical and neuro-physiological study" by A. Silva, K. Maduwage, M. Sedgwick, S. Pilapitiya, P. Weerawansa, N.J. Dahanayaka, N.A. Buckley, S. Siribaddana and G.K. Isbister emphasises that similar to the hump nosed pit vipers, the juvenile Russell’s viper usually does not cause neurotoxicity, and that both the snakes cause venom induced consumption coagulopathy and acute kidney injury, while local effects may not be prominent enough to distinguish them in some cases. Although adult Russell’s vipers are much larger snakes, the juvenile Russell’s vipers could almost be the same size as the hump-nosed pit vipers. In a specimen with an undamaged head, examining the presence or absence of a raised snout or the loreal pit (the deep depression, or fossa, in the loreal area on either side of the head in pit vipers, which is located behind the nostril and in front of the eye, but below the line that runs between the centre of each) could assist in differentiating the hump nosed pit vipers. The Russell’s viper has large nostrils, but no pits (a notable hole) between the nostril and the eye. The Russell’s viper also has an unmistakable body colour pattern with three rows of dark elliptical markings with clear margins (often black and white) running along the body. Of these, the middle row runs dorsally and the other two run on each side of the body. In some specimens, a few of these elliptical markings could also be fused or faded. These markings are much darker, almost close to black in juveniles. In addition, a white colour 'inverted V' mark could also be seen on the head. In contrast, hump nosed pit vipers have two rows of dark, often triangular, blotches running on either side of the midline. However, the base body colouration of the hump nosed pit vipers could vary greatly, so too the colour and the shape of the dark blotches. Distinguishing the saw scaled viper is straightforward because it is exclusively found in the arid zone, and there is a characteristic series of white blotches connected to the white arches running along the body. In addition, a ‘bird foot mark’ could be seen dorsally on the head. However, this mark may appear in oval or diamond shape as well.

A black, grey or dark brown snake with white bands is perhaps the most confusing scenario that a medical officer could face. This is because several non-venomous snakes such as wolf snakes (Lycodon species) and bridal snakes (Dryocalamus species) mimic the colouration of the medically important kraits (the Bungarus genus). Kraits have prominently enlarged, hexagonal scale rows on the midline of the dorsal side of the body (vertebral scale row), whereas the vertebral scale row is not notably different to the lateral scales in the other group of snakes. Scales under the tail in kraits are arranged as a single row (uniserial subcaudal scales) and the Sri Lankan wolf snake too has the same, whereas they are paired in the other group of snakes. To confirm a krait specimen, a medical officer should check the snake specimen for the presence of both these characters. Kraits also have non-keeled, smooth and notably shiny scales and smaller heads. Indian and Sri Lankan kraits could be clearly distinguished based on their colouration. The juveniles and young specimens of the Indian krait, for the large part, have narrow white bands arranged in pairs, while the Sri Lankan krait specimens have broad, individually arranged white bands. However, both these species tend to lose their white bands when they become mature and at times, some Indian kraits have fused bands that look thicker and resemble those of Sri Lankan kraits. Therefore, it is not uncommon to find mature, large snakes of both these species, without a single white band, often referred to as ‘Habarala’ in some parts of the country. The ventral side of the Indian krait is uniformly white, while the ventral side of the Sri Lankan krait is black or dark with white bands. However, the juveniles of the Sri Lankan kraits have uniformly white colour ventral sides. These two species could be separated based on their distribution. The Indian krait is distributed mainly in the dry zone while the Sri Lankan krait is limited to the wet zone, with possible overlap of their distributions in the intermediate zone. There are also increasing recent records of Indian kraits in the Western coastal belt as well as around Colombo. However, a patient from a wet zone is less likely to have an Indian krait bite while a patient in the dry zone is unlikely to have a Sri Lankan krait bite.

The Sri Lankan cobra and rat snake both exist almost throughout the country and both these snakes are common around human settlements. A live, defensive cobra could be unmistakably identified due to its display of the hood. Dead specimens can be identified using a combination of markings on the neck (both dorsally and ventrally) and the number of dark edges on the lip scales. The neck of dead specimens can be stretched to confirm the presence or absence of markings. Rat snakes also have notably large eyes compared to their head size. The Sri Lankan cobra has narrow white bands on the dorsal side of the body and some rat snakes too have the same colour pattern.

These scenarios are the most commonly encountered confusions in Sri Lankan healthcare settings with regard to snakebite management. Therefore, Silva et al. elaborate that it is advisable to thoroughly go through these scenarios prior to treatment.