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Background: Crude venom of the banded tiger waspVespa affinis contains a variety of enzymes including hyaluronidases, commonly known as spreading factors. Methods: The cDNA cloning, sequence analysis and structural modelling of V. affinis venom hyaluronidase (VesA2) were herein described. Moreover, heterologous expression and mutagenesis of rVesA2 were performed. Results: V. affinis venom hyaluronidase full sequence is composed of 331 amino acids, with four predicted N-glycosylation sites. It was classified into the glycoside hydrolase family 56. The homology modelling exhibited a central core (α/β)7 composed of Asp107 and Glu109, acting as the catalytic residues. The recombinant protein was successfully expressed in E. coli with hyaluronidase activity. A recombinant mutant type with the double point mutation, Asp107Asn and Glu109Gln, completely lost this activity. The hyaluronidase from crude venom exhibited activity from pH 2 to 7. The recombinant wild type showed its maximal activity at pH 2 but decreased rapidly to nearly zero at pH 3 and was completely lost at pH 4. Conclusion: The recombinant wild-type protein showed its maximal activity at pH 2, more acidic pH than that found in the crude venom. The glycosylation was predicted to be responsible for the pH optimum and thermal stability of the enzymes activity.

Vespa affinis stings are known to produce local as well as systemic toxic manifestations including haemolysis, rhabdomyolysis, renal injury, hepatic toxicity and encephalopathy. However, very few pediatric cases of Vespa affinis stings have been reported. An unusual case of a toddler with hornet stings (10 in number) is reported who presented to our hospital 72 hours after the sting and met with a fatal outcome. At the time of presentation, child was in altered sensorium and shock with multiple necrotic sting marks. Blood investigations were suggestive of acute renal failure with dyselectrolytemia, rhabdomyolysis and toxic liver injury. Child was managed conservatively with intravenous fluids, renal sparing antibiotics, inotropes, fresh frozen plasma and intravenous high dose steroid (Methyl Prednisolone 30 mg/kg/dose). However, the child deteriorated and had a cardiac arrest the same day. She was resuscitated, intubated and connected to a ventilator. The condition worsened and the child succumbed to death. Since there is no specific treatment, a rare case of hornet bite with acute toxic liver injury and rhabdomyolysis could be a challenge to treat.

Wasp sting is a relatively common arthropod assault. This usually results in pain and mild allergic reactions, but sometimes may cause severe systemic reaction and multiorgan dysfunction including rhabdomyolysis, hemolysis, coagulopathy, hepatic, renal and cardiac complications. Along with several other pathomechanisms, rhabdomyolysis is a distinguished cause of acute kidney injury (AKI) in patients with wasp sting. We herein report a case in which the patient developed rhabdomyolysis followed by AKI due to multiple wasp stings. The offending wasp was brought to the hospital and the species was confirmed by a zoologist (Vespa affinis).

Introduction Vespa affinis is a hornet widely distributed in Sri Lanka and it is responsible for the highest number of deaths related to Hymenoptera stings. Apart from the early reactions, victims often die in hospital many hours later due to complications such as myocardial infarction and multiple organ failure. Increased microvascular permeability and acute pulmonary oedema as the primary pathology is less known in hornet envenoming. Case presentation Here, we report clinical and postmortem findings of two Sinhalese patients, a 48-year-old husband and his 46-year-old wife, who both died following a massive attack by hornets 32 hours and 9 hours after the incidence respectively. At postmortem examination, both patients had pleural effusions, acute pulmonary oedema and red cell casts in their urine. Their coronary arteries and histology of myocardium were normal. Conclusion Early recognition of acute pulmonary oedema in hornet stings is needed with implementation of crucial treatments to avert deaths.

Background Acute coronary syndrome after hymenoptera stings or exposure to environment toxins is referred to as the Kounis syndrome or allergic myocardial ischaemia with or without infarction. We report a case of hornet (Vespa affinis) sting causing Kounis syndrome in Sri Lanka and present a review of literature. Case presentation A 60-year -old female with diabetes mellitus and known allergy to bee venom was stung by a hornet on the right hand. Within 30 minutes she developed hypotension and wide spread T wave inversion in the 12 leads ECG that remained unchanged about 5 hours and reversed back to normal. Conclusion Hymenoptera stings can induce acute coronary syndrome either by direct effect of venom constituents on the coronary endothelium or through inflammatory mediators induced allergic reaction on coronary vasculature. Early recognition of Kounis syndrome is needed in hornet stings to implement necessary treatments.

Although most species of wasps are solitary and no hazard to humans, attacks by colonies of large social wasps of the family Vespidae, which commonly are known as hornets, can result in envenomation with severe toxicity. The effects of such envenomation on six persons from Papua New Guinea are described and discussed in the light of other published reports from Melanesia, Asia, Europe and America. Four deaths and at least four cases of acute renal failure occurred. Vespa affinis (L.), 1764 was responsible for at least two deaths and Vespa tropica (L.), 1764 for one death. The ecology of vespids in Asia and the Pacific is reviewed and guide-lines for the prevention of wasp attacks are outlined, including appropriate clothing, and the recognition, avoidance and selective destruction of nests. A description is helpful in the identification of the species of insect that was responsible for clinical cases. Management includes hospitalization for victims of multiple stings, with careful monitoring for early and late damage to kidneys, blood, liver and muscle.