In their countries of origin, experts had already documented and associated, in addition to the reaction of the sting itself, other health effects, such as acute renal failure. “The literature on wasps and acute renal failure is scarce and mostly from Asia, so nephrologists outside Asia are not familiar with this health problem,” explains Alberto Ortiz, a researcher at the Fundación Jiménez Díaz and co-author of an editorial in the Clinical Kidney Journal.
According to the authors, although this complication has probably been present for millennia, existing health reports on the association between Asian wasp stings and kidney failure are relatively recent. In fact, the first one was made in Thailand in 1972, and since then most of them have been from Asia. As of January 2022, the databases contained 73 reports from 19 countries, 15 of them in Asia.
“Nephrologists in Europe and North America may not be aware of a health problem that is increasingly recognised,” says Sol Carriazo, a researcher in the Department of Medicine at the Autonomous University of Madrid and co-author of the commentary. On both continents, the toxicity of native wasps is lower than that of Asian wasps.
How to react to stings
However, what does reach the experts is the news about these invasive species and the social alarm created through the media. V. mandarinia has been detected since 2019 in western British Columbia (Canada) and Washington State (USA), and is a problem for bees and humans.
“In Europe, V. velutina arrived in Bordeaux, France, in 2005 and has since spread to Italy, Germany, Belgium, the Netherlands, the UK, Spain and Portugal, where it kills honey bees. Both species can induce acute kidney damage or be lethal in humans,” says Ortiz. In addition, the black shield wasp (V. bicolor), native to China, and the oriental hornet (V. orientalis) have also been detected in Spain.
According to a study, carried out by Chinese researchers at the Suining Central Hospital from the analysis of 1,131 patients with wasp stings, the Asian giant hornet and the Asian wasp were among those causing the most hospitalisations, although most cases were caused by the black-tailed hornet (V. basalis).
The hospital established a protocol with anti-allergic or anti-shock treatment; local treatment (removal of stings, local dexamethasone and lidocaine); elimination of toxins and prevention of acute kidney injury caused by rhabdomyolysis and haemolysis; analgesia and tetanus antitoxin. In severe patients with multiple stings, they used continuous venous haemofiltration, haemoperfusion or plasma exchange to improve prognosis with the aim of expelling toxins that could lead to organ failure.
To reduce mortality in the most severe cases, the scientists applied a wasp sting severity assessment or index to 153 patients in 2020 based on the observation of four aspects: tea-coloured urine, number of stings, lactate dehydrogenase -an enzyme found in different tissues of the body- and total bilirubin.
If the severity index results are equal to or greater than three, experts suggest the need for an early plasma exchange (within 24 hours of the sting). However, under these same conditions, they do not consider continuous venovenous haemofiltration and haemoperfusion to reduce mortality.
Although this methodology still requires external validation, the authors suggest that the information it provides could serve as a guide to action and raise awareness of the effects of these attacks.
Sol Carriazo et al. “Wasp stings and plasma Exchange” Clinical Kidney Journal.