Kalana Maduwage - Academia.edu (original) (raw)

Papers by Kalana Maduwage

Zenodo (CERN European Organization for Nuclear Research), Apr 29, 2020

The dwarf snakehead Channa gachua (Hamilton, 1822) (type locality Bengal) has been reported from ... more The dwarf snakehead Channa gachua (Hamilton, 1822) (type locality Bengal) has been reported from a vast range, from Iran to Taiwan, and northern India to Sri Lanka. Here, adopting an integrative taxonomic approach, we show that the Sri Lankan snakehead previously referred to as C. gachua is in fact a distinct species, for which the name C. kelaartii (Günther, 1861) is available. Widely distributed in streams and ponds throughout Sri Lanka's lowlands, and also recorded here from the east-flowing drainages of southern peninsular India, C. kelaartii is distinguished from all the other species of the C. gachua species group by the combination of head shape, dorsal-and anal-fin ray counts, scale counts, the presence of pelvic fins, and live adult coloration. Further, C. kelaartii is genetically distinct from topotypical C. gachua by an uncorrected pairwise distance of 7.9-8.8 % for the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene.

Ceylon Journal of Science, Biological Sciences, Apr 3, 2013

The morphology of hemipenes, the male external genitalia of reptiles, is considered to be a chara... more The morphology of hemipenes, the male external genitalia of reptiles, is considered to be a character of taxonomic importance. It has, however, until recently been used only rarely in agamid systematics. Phylogenies of Sri Lankan Agamidae, constructed using mitochondrial DNA and hemipeneal morphology, have shown remarkable convergence, highlighting the importance of hemipeneal morphology in the taxonomy of these lizards. Here we present descriptions and illustrations of the hemipenes of 17 of the 18 species of Sri Lankan Agamidae and provide a key to the identification of species groups based on this character.

Frontiers in Medicine, Mar 7, 2022

Background: Venom-induced consumption coagulopathy (VICC) is an important clinical consequence of... more Background: Venom-induced consumption coagulopathy (VICC) is an important clinical consequence of Russell's viper (Daboia russelii) envenoming. There is limited evidence for antivenom effectiveness in resolving VICC. We aimed to compare the recovery of VICC in patients who received and did not receive antivenom following Russell's viper envenoming. Patients and Methods: This was a non-randomized observational study comparing patients with VICC from Russell's viper envenoming given antivenom for systemic envenoming and those not given antivenom. Antivenom administration was decided by the treating physicians. We included 44 patients with confirmed Russell's viper bites with one or more International Normalized Ratio (INR) value ≥ 1.5 (VICC). We compared five patients who did not receive antivenom with 39 patients who did receive antivenom. The primary outcome was the proportion of patients with an INR < 1.5 by 48 h post-bite. Results: The antivenom group had higher peak serum venom concentrations [median (IQR) = 272 (96-1,076) ng/mL versus 21 (8-58) ng/mL] and more severe VICC compared to the no antivenom group. Twenty seven of 39 patients (69%) in the antivenom group had an INR < 1.5 at 48 h post-bite compared to none of the five patients (0%) in the no antivenom group (absolute difference: 69%; 95%CI: 13 to 83%; p = 0.006; Fisher's exact test). The fibrinogen recovered in 32 of 39 patients (82%) in the antivenom group compared to one of five patients (20%) in the no antivenom group (absolute difference 62%; 95% CI: 28 to 95%; p = 0.001; Fisher's exact test). Both

Scientific Reports, Apr 29, 2014

Coagulopthy, acute kidney injury and death following Hypnale zara envenoming – The first case report from Sri Lanka

Toxicon, Dec 1, 2011

Snakebite is a major medical problem in developing Asia. Hump-nosed pit viper (Genus Hypnale) cau... more Snakebite is a major medical problem in developing Asia. Hump-nosed pit viper (Genus Hypnale) causes the most number of snakebites with significant morbidity and mortality in Sri Lanka. Even though there are three species (Hypnale hypnale, Hypnale zara and Hypnale nepa) in Sri Lanka there are few published literature on species-specific clinico-epidemiological data. This report describes an authenticated fatal case of a 47 years old male due to coagulopthy and acute kidney injury following envenoming by H. zara in Sri Lanka.

Journal of Thrombosis and Haemostasis, Apr 1, 2017

Lincz LF, Buckley NA. A randomized controlled trial of fresh frozen plasma for coagulopathy in Ru... more Lincz LF, Buckley NA. A randomized controlled trial of fresh frozen plasma for coagulopathy in Russell's viper (Daboia russelii) envenoming.

BMC Research Notes, Aug 29, 2012

Background: Envenoming by south Asian hump-nosed pit vipers (Genus: Hypnale) is a significant hea... more Background: Envenoming by south Asian hump-nosed pit vipers (Genus: Hypnale) is a significant health issue in Sri Lanka and in peninsular India. Bites by these snakes frequently lead to local envenoming, coagulopathy and acute renal failure even resulting in death. Recently the genus was revised and the existence of three species viz H. hypnale, H. nepa and H. zara were recognized. There is, however, a paucity of information on the toxicity of the venoms of these species. Hence, we compared the toxic effects of the three Hypnale venoms using BALB/c mice. Findings: Intraperitoneal median lethal doses (LD 50) for H. hypnale, H. zara and H. nepa venoms were 1.6, 6.0 and 9.5 μg protein/g respectively. Minimum haemorrhagic doses for venoms of H. hypnale, H. zara and H. nepa were 3.4, 11.0 and 16.6 μg protein/mouse respectively. The minimum necrotic doses for the same venoms were 15.0, 55.1 and 68.2 μg protein/mouse respectively. Severe congestion and petecheal haemorrhages were observed in lungs, kidneys, liver and the alimentary tract. Histopathogical examination of kidneys revealed proximal tubular cell injury and acute tubular necrosis with intact basement membrane indicating possible direct nephrotoxicity. Hypnale venoms caused pulmonary oedema, hepatocellular degeneration and necrosis, focal neuronal degeneration in brain and extramedullary haemopoiesis in spleen. H. hypnale venom caused all above histopathological alterations at lower doses compared to the other two. Conclusion: Hypnale venoms cause similar pathological changes with marked differences in the severity of the toxic effects in vivo. Therefore, differences in the severity of the clinical manifestations could possibly be seen among bite victims of the three Hypnale species.

Zenodo (CERN European Organization for Nuclear Research), Dec 31, 2008

Since its first record from the island in 1912, the barb Puntius amphibius Valenciennes has regul... more Since its first record from the island in 1912, the barb Puntius amphibius Valenciennes has regularly featured in Sri Lanka's ichthyofaunal inventories. Recent work has shown, however, that the name P. amphibius should be reserved for a species originally collected from Bombay, India, and described by Achille Valenciennes in 1842, now known only from its lectotype. The Sri Lankan fish hitherto known by this name is an undescribed species. Puntius kamalika, new species, is distinguished from all Sri Lankan and peninsular-Indian congeners by having (in addition to a suite of mensural characters) ½4/1/2½ scales in transverse line between mid-dorsal scale row and pelvic-fin origin and lacking any prominent markings on fins and body in both living and preserved examples. The new species is widely distributed in the island's wet-zone lowlands (rainfall > 2,500 mm yr-1), where it occurs in streams, rivers and marshes between the Kelani-River basin draining to the island's west, and the Gin River basin to the south. It is locally common.

The Cochrane library, Mar 21, 2017

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess... more This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the effects of antivenom on neuromuscular paralysis in people with neurotoxic snake envenoming.

Journal of Pharmacological and Toxicological Methods, May 1, 2013

Introduction: Immunoturbidimetry studies the phenomenon of immunoprecipitation of antigens and an... more Introduction: Immunoturbidimetry studies the phenomenon of immunoprecipitation of antigens and antibodies in solution, where there is the formation of large, polymeric insoluble immunocomplexes that increases the turbidity of the solution. We used immunoturbidimetry to investigate the interaction between commercial snake antivenoms and snake venoms, as well as cross-reactivity between different snake venoms. Methods: Serial dilutions of commercial snake antivenoms(100µl) in water were placed in the wells of a microtitre plate and 100µl of a venom solution (50µg/ml in water) was added. Absorbance readings were taken at 340nm every minute on a BioTek ELx808 plate reader at 37ºC. Limits imposed were a 30 minute cutoff and 0.004 as the lowest significant maximum increase. Reactions with rabbit antibodies were carried out similarly, except that antibody dilutions were in PBS. Results: Mixing venom and antivenom/antibodies resulted in an immediate increase in turbidity, which either reached a maximum or continued to increase until a 30 minute cutoff. There was a peak in absorbance readings for most Australian snake venoms mixed with the corresponding commercial antivenom, except for P. textilis venom and brown snake antivenom. There was cross-reactivity between Naja naja venom from Sri Lanka and tiger snake antivenom indicated by turbidity when they were mixed. Mixing rabbit anti-snake antibodies with snake venoms resulted in increasing turbidity, but there was not a peak suggesting the antibodies were not sufficiently concentrated. The absorbance reading at predetermined concentrations of rabbit antibodies mixed with different venoms was able to quantify the cross-reactivity between venoms. Indian antivenoms from two manufacturers were tested against four Sri Lankan snake venoms (D. russelli, N. naja, E. carinatus and B. caeruleus) and showed limited formation of immunocomplexes with antivenom from one manufacturer. Discussion: The turbidity test provides an easy and rapid way to compare and characterise interactions between antivenoms and snake venoms.

Zenodo (CERN European Organization for Nuclear Research), Dec 31, 2009

The hump-nosed pit vipers of the genus Hypnale are of substantial medical importance in Sri Lanka... more The hump-nosed pit vipers of the genus Hypnale are of substantial medical importance in Sri Lanka and India, being included among the five snakes most frequently associated with life-threatening envenoming in humans. The genus has hitherto been considered to comprise three species: H. hypnale, common to Sri Lanka and the Western Ghats of peninsular India; and H. nepa and H. walli, both of which are endemic to Sri Lanka. The latter two species have frequently been confused in the literature. Here, through a review of all extant name-bearing types in the genus, supplemented by examination of preserved specimens, we show that H. nepa is restricted to the higher elevations of Sri Lanka's central mountains; that H. walli is a junior synonym of H. nepa; and that the endemic species widely distributed in the island's southwestern 'wet-zone' lowlands is H. zara. We also draw attention to a possibly new species known only from a single specimen collected near Galle in southern Sri Lanka. We illustrate all four species in colour, and provide a key to their identification and maps delineating their distribution.

Zootaxa, Nov 12, 2008

The Sri Lankan population of the spiny eel previously assigned to Macrognathus aral Schneider (Te... more The Sri Lankan population of the spiny eel previously assigned to Macrognathus aral Schneider (Teleostei: Mastacembelidae) is shown to be a distinct species, for which the name M. pentophthalmos Gronow is available. Macrognathus pentophthalmos is distinguished from its closest congener, M. aral, by having 14-16 dorsal spines and a pre-dorsal length of 43.3-46.8% of standard length (SL) (vs. dorsal spines 18-22 and pre-dorsal length 35.5-40.8% SL in M. aral). Macrognathus pentophthalmos differs from its only other Indian congener, M. guentheri Day, among other characters, by having 24 pairs of rostral tooth plates (vs. rostral tooth plates absent). With the present designation of a neotype, Rhynchobdella orientalis Bloch & Schneider (type locality East Indies to Sri Lanka) becomes an objective junior synonym of M. aculeatus Bloch. Although assessed as 'common' in 1980, the population of M. pentophthalmos suffered a precipitous decline in the following decade, the causes of which are unknown. The species may now be extinct.

Wilderness & Environmental Medicine, Mar 1, 2014

Background.-Although snake bite remains a major health problem in Sri Lanka, there is a dearth of... more Background.-Although snake bite remains a major health problem in Sri Lanka, there is a dearth of baseline information that would be useful in education about and prevention of snakebite. Objectives.-The purpose of this study was to describe the socio-demographic characteristics, behavioral responses, treatment seeking, and prehospital interventions of snakebite victims in an area with high snakebite burden. Methods.-This prospective study was based on a cohort of snakebite victims presented to the Anuradhapura Teaching Hospital over a 1-year period from January 2010. Results.-Of the total of 1018 snakebite admissions, 69% were male and 65.8% were aged 21 to 50 years. Most of the victims were farmers (40%). The offending snakes were seen by 549 victims (54%); of these, only 46% (255) presented with a dead snake specimen. Only 38 of 1018 (4%) had first sought some form of indigenous treatment such as locally applied medications, herbal decoctions, nasal insufflations ("Nasna"), or applying snake stone over the bitten site. Some form of first aid had been adopted by 681 victims (67%), of whom all had washed the bitten site, and 18 victims (2%) and 4 (0.4%) had applied a dressing or incised the bitten site, respectively. A tourniquet had been applied by 353 victims (35%) for mean duration of 26 minutes (range, 5 to 120 minutes). None of the patients had immobilized the bitten limb by splinting. Oral medications had been used for pain relief in 74 cases (7%), paracetamol by all. Conclusions.-A proportion of patients still seek native remedies and use inappropriate first aid after snakebite in Sri Lanka.

Special issue editorial: Resource mapping for the management of snakebite envenomation

Toxicon: X

Dataset for "Neuromuscular effects of common Krait (Bungarus caeruleus) envenoming in Sri Lanka

Public Library of Science, 2015

PLOS Neglected Tropical Diseases, 2020

Background Detection and quantification of snake venom in envenomed patients' blood is important ... more Background Detection and quantification of snake venom in envenomed patients' blood is important for identifying the species responsible for the bite, determining administration of antivenom, confirming whether sufficient antivenom has been given, detecting recurrence of envenoming, and in forensic investigation. Currently, snake venom detection is not available in clinical practice in Sri Lanka. This study describes the development of enzyme immunoassays (EIA) to differentiate and quantify venoms of Russell's viper (Daboia russelii), saw-scaled viper (Echis carinatus), common cobra (Naja naja), Indian krait (Bungarus caeruleus), and hump-nosed pit viper (Hypnale hypnale) in the blood of envenomed patients in Sri Lanka. Methodology / Principal findings A double sandwich EIA of high analytical sensitivity was developed using biotin-streptavidin amplification for detection of venom antigens. Detection and quantification of D. russelii, N. naja, B. caeruleus, and H. hypnale venoms in samples from envenomed patients was achieved with the assay. Minimum (less than 5%) cross reactivity was observed between species, except in the case of closely related species of the same genus (i.e., Hypnale). Persistence/ recurrence of venom detection following D. russelii envenoming is also reported, as well as detection of venom in samples collected after antivenom administration. The lack of specific antivenom for Hypnale sp envenoming allowed the detection of venom antigen in circulation up to 24 hours post bite. Conclusion The EIA developed provides a highly sensitive assay to detect and quantify five types of Sri Lankan snake venoms, and should be useful for toxinological research, clinical studies, and forensic diagnosis.

Archives of Disease in Childhood, 2020

Snakebite in children can often be severe or potentially fatal, owing to the lower volume of dist... more Snakebite in children can often be severe or potentially fatal, owing to the lower volume of distribution relative to the amount of venom injected, and there is potential for long-term sequelae. In the second of a two paper series, we describe the pathophysiology of snakebite envenoming including the local and systemic effects. We also describe the diagnosis and management of snakebite envenoming including prehospital first aid and definitive medical and surgical care.

of Medicine, University of Peradeniya

Thrombosis Research, 2016

Background: Animal models are used to test toxic effects of snake venoms/toxins and the antivenom... more Background: Animal models are used to test toxic effects of snake venoms/toxins and the antivenom required to neutralise them. However, venoms that cause clinically relevant coagulopathy in humans may have differential effects in animals. We aimed to investigate the effect of different procoagulant snake venoms on various animal plasmas. Methods: Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and D-dimer levels were measured in seven animal plasmas (human, rabbit, cat, guinea pig, pig, cow and rat). In vitro clotting times were then used to calculate the effective concentration (EC 50) in each plasma for four snake venoms with different procoagulant toxins: Pseudonaja textilis, Daboia russelli, Echis carinatus and Calloselasma rhodostoma. Results: Compared to human, PT and aPTT were similar for rat, rabbit and pig, but double for cat and cow, while guinea pig had similar aPTT but double PT. Fibrinogen and D-dimer levels were similar for all species. Human and rabbit plasmas had the lowest EC 50 for P. textilis (0.1 and 0.4 μg/ml), D. russelli (0.4 and 0.1 μg/ml), E. carinatus (0.6 and 0.1 μg/ml) venoms respectively, while cat plasma had the lowest EC 50 for C. rhodostoma (11 μg/ml) venom. Cow, rat, pig and guinea pig plasmas were highly resistant to all four venoms with EC 50 10-fold that of human. Conclusions: Different animal plasmas have varying susceptibility to procoagulant venoms, and excepting rabbits, animal models are not appropriate to test procoagulant activity. In vitro assays on human plasma should instead be adopted for this purpose.

Figure 5 In Two New Species Of Rhinophis Hemprich (Serpentes: Uropeltidae) From Sri Lanka

FIGURE 5. Hemipenis of paratype (WHT 5208) of Rhinophis lineatus sp. nov. Scale bar = 1 mm.