Stinging insect identification: Are the allergy specialists any better than their patients?

[Insect venom allergies-What will change in times of global change?]

BACKGROUND

In Germany, honeybees (Apis mellifera) and various Vespula species (wasps) are primarily relevant for hypersensitivity reactions to stings. Hornets (Vespa crabro), bumblebees, paper wasps (Polistes) and yellowjackets (Dolichovespula) less frequently cause sting reactions.

OBJECTIVE

What effects do intensive agricultural utilization and climate change have on the living conditions and occurrence of Hymenoptera and what consequences do they have for the diagnostics and treatment of hypersensitivity reactions to Hymenoptera stings.

MATERIAL AND METHODS

A literature search was carried out.

RESULTS

Honeybees and wild bees are endangered due to introduced diseases, invasive species and pesticides. The aim of widespread beekeeping activity is to protect honeybees, which is why no reduction in stings is to be expected despite increased bee mortality. In Germany, there is evidence of the spread of thermophilic Polistes species (paper wasps) from south to north and the immigration of Vespa velutina nigrithorax (Asian hornet). It is unlikely that these species will lead to a significant increase in sting reactions. Nests of the red fire ant (Solenopsis invicta), which was originally common in South America, were first detected in Sicily in 2022. Red fire ants are aggressive insects with a high potential for adverse sting reactions.

CONCLUSION

Invasive insects must be considered as a trigger in the anamnesis and diagnostics. Diagnostics are only available for the detection of Polistes sensitization. Therapeutic allergens can be obtained from other European countries for venom immunotherapy of a Polistes allergy. Due to cross-reactivity, diagnostic and therapeutic allergens from Vespula spp. are used for the diagnosis and treatment of suspected allergies to the Asian hornet.

Diagnosis of Hymenoptera Venom Allergy: State of the Art, Challenges, and Perspectives

Hymenoptera venom allergy is the most common cause of anaphylaxis in adults and the second-most frequent in children. The proper diagnosis of this life-threatening allergy remains a challenge. This review focuses on the current knowledge regarding diagnostics of Hymenoptera venom allergy. The paper includes a brief description of the representatives of Hymenoptera order and the composition of their venoms. Then, diagnostic tests for allergy to Hymenoptera venom are described. Common diagnostic problems, especially double positivity in tests for IgE antibodies specific to honeybee and wasp venom, are also discussed. Special attention is paid to the search for new diagnostic capabilities using modern methodologies. Multidimensional molecular analysis offers an opportunity to characterize changes in body fluids associated with Hymenoptera venom allergy and yields a unique insight into the cell status. Despite recent developments in the diagnostics of Hymenoptera venom allergy, new testing methodologies are still needed to answer questions and doubts we have.

Ant sting-induced whole-body pustules in an inebriated male: A case report

BACKGROUND

Many ant species can harm humans; however, only a few cause life-threatening allergic reactions. Normally, reactions caused by ants occur in patients who come into contact with ant venom. Venom contains various biologically active peptides and protein components, of which acids and alkaloids tend to cause anaphylaxis. Ant venom can cause both immediate and delayed reactions. The main histopathological changes observed in ant hypersensitivity are eosinophil recruitment and Th2 cytokine production.

CASE SUMMARY

A 70-year-old man was bitten by a large number of ants when he was in a drunken stupor and was hospitalized at a local hospital. Five days later, because of severe symptoms, the patient was transferred to our hospital for treatment. Numerous pustules were observed interspersed throughout the body, with itching and pain reported. He had experienced fever, vomiting, hematochezia, mania, soliloquy, sleep disturbances, and elevated levels of myocardial enzymes since the onset of illness. The patient had a history of hypertension for more than 1 year, and his blood pressure was within the normal range after hypotensive drug treatment. He had no other relevant medical history. Based on the clinical history of an ant bite and its clinical manifestations, the patient was diagnosed with an ant venom allergy. The patient was treated with 60 mg methylprednisolone for 2 d, 40 mg methylprednisolone for 3 d, and 20 mg methylprednisolone for 2 d. Oral antihistamines and diazepam were administered for 12 d and 8 d, respectively. Cold compresses were used to treat the swelling during the process. After 12 d of treatment, most pustules became crusts, whereas some had faded away. No symptoms of pain, itching, or psychological disturbances were reported during the follow-up visits within 6 mo.

CONCLUSION

This case report emphasizes the dangers of ant stings.

What We Know about Sting-Related Deaths? Human Fatalities Caused by Hornet, Wasp and Bee Stings in Europe (1994-2016)

Simple Summary

Information about fatalities due to stinging insects is scarce. Hymenopteran-related deaths (n = 1691) in 32 European countries based on official registers over a 23-year period (1994–2016) are described. Male adults (25–64 years) were the most common group to be fatally injured and almost half of the fatalities were recorded at “unspecified places”. Fatalities per million inhabitants per year ranged from 0 to 2.24 with an average of 0.26. Geographic, environmental, and ecological factors influence the frequency of stings, and its subsequent reaction. It is necessary to produce and interpret knowledge using diverse sources and in an interdisciplinary way. As part of the One Health philosophy, people and hornets, wasps and bees, as well as the environment that they share are closely connected.

Abstract

Epidemiology of Hymenopteran-related deaths in Europe, based on official registers from WHO Mortality Database (Cause Code of Death: X23), are presented. Over a 23-year period (1994–2016), a total of 1691 fatalities were recorded, mostly occurring in Western (42.8%) and Eastern (31.9%) Europe. The victims tended to concentrate in: Germany (n = 327; 1998–2015), France (n = 211; 2000–2014) and Romania (n = 149; 1999–2016). The majority of deaths occurred in males (78.1%) between 25–64 years (66.7%), and in an “unspecified place” (44.2%). The highest X23MR (mortality rate) were recorded in countries from Eastern Europe (0.35) followed by Western (0.28), Northern (0.23) and Southern Europe (0.2). The countries with the highest and lowest mean X23MR were Estonia (0.61), Austria (0.6) and Slovenia (0.55); and Ireland (0.05), United Kingdom (0.06) and the Netherlands (0.06), respectively. The X23 gender ratio (X23GR; male/female) of mortality varied from a minimum of 1.4 for Norway to a maximum of 20 for Slovenia. Country-by-country data show that the incidence of insect-sting mortality is low and more epidemiological data at the regional level is needed to improve our understanding of this incidence. With the expansion of non-native Hymenopteran species across Europe, allergists should be aware that their community’s exposures are continually changing

Characterization of New Allergens from the Venom of the European Paper Wasp Polistes dominula

Discriminating Polistes dominula and Vespula spp. venom allergy is of growing importance worldwide, as systemic reactions to either species’ sting can lead to severe outcomes. Administering the correct allergen-specific immunotherapy is therefore a prerequisite to ensure the safety and health of venom-allergic patients. Component-resolved diagnostics of Hymenoptera venom allergy might be improved by adding additional allergens to the diagnostic allergen panel. Therefore, three potential new allergens from P. dominula venom—immune responsive protein 30 (IRP30), vascular endothelial growth factor C (VEGF C) and phospholipase A2 (PLA2)—were cloned, recombinantly produced and biochemically characterized. Sera sIgE titers of Hymenoptera venom-allergic patients were measured in vitro to assess the allergenicity and potential cross-reactivity of the venom proteins. IRP30 and VEGF C were classified as minor allergens, as sensitization rates lay around 20–40%. About 50% of P. dominula venom-allergic patients had measurable sIgE titers directed against PLA2 from P. dominula venom. Interestingly, PLA2 was unable to activate basophils of allergic patients, questioning its role in the context of clinically relevant sensitization. Although the obtained results hint to a questionable benefit of the characterized P. dominula venom proteins for improved diagnosis of venom-allergic patients, they can contribute to a deeper understanding of the molecular mechanisms of Hymenoptera venoms and to the identification of factors that determine the allergenic potential of proteins.

Global View on Ant Venom Allergy: from Allergenic Components to Clinical Management

Hymenoptera venom allergy is characterised by systemic anaphylactic reactions that occur in response to stings from members of the Hymenoptera order. Stinging by social Hymenoptera such as ants, honeybees, and vespids is one of the 3 major causes of anaphylaxis; along with food and drug exposure, it accounts for up to 43% of anaphylaxis cases and 20% of anaphylaxis-related fatalities. Despite their recognition as being of considerable public health significance, stinging ant venoms are relatively unexplored in comparison to other animal venoms and may be overlooked as a cause of venom allergy. Indeed, the venoms of stinging ants may be the most common cause of anaphylaxis in ant endemic areas. A better understanding of the natural history of venom allergy caused by stinging ants, their venom components, and the management of ant venom allergy is therefore required. This article provides a global view on allergic reactions to the venoms of stinging ants and the contemporary approach to diagnose and manage ant venom allergy.

Precision Medicine in Hymenoptera Venom Allergy: Diagnostics, Biomarkers, and Therapy of Different Endotypes and Phenotypes

Allergic reactions to stings of Hymenoptera species may be severe and are potentially fatal deviations of the immunological response observed in healthy individuals. However, venom-specific immunotherapy (VIT) is an immunomodulatory approach able to cure venom allergy in the majority of affected patients. An appropriate therapeutic intervention and the efficacy of VIT not only depend on a conclusive diagnosis, but might also be influenced by the patient-specific manifestation of the disease. As with other diseases, it should be borne in mind that there are different endotypes and phenotypes of venom allergy, each of which require a patient-tailored disease management and treatment scheme. Reviewed here are different endotypes of sting reactions such as IgE-mediated allergy, asymptomatic sensitization or a simultaneous presence of venom allergy and mast cell disorders including particular considerations for diagnosis and therapy. Additionally, phenotypical manifestations of venom allergy, as e.g. differences in age of onset and disease severity, multiple sensitization or patients unsusceptible to therapy, are described. Moreover, biomarkers and diagnostic strategies that might reflect the immunological status of the patient and their value for therapeutic guidance are discussed. Taken together, the increasing knowledge of different disease manifestations in venom hypersensitivity and the growing availability of diagnostic tools open new options for the classification of venom allergy and, hence, for personalized medical approaches and precision medicine in Hymenoptera venom allergy.

Hymenoptera venom allergy among children in Italy: time for pediatricians to take action

Hymenoptera venom allergy (HVA) is one of the most frequent causes of anaphylaxis following a bee, vespid or ant sting. Real-life data regarding the management of HVA in children are lacking. To address this unmet need, we carried out a survey defining the current management of HVA in children among pediatric allergists in Italy. Educational investments on the improvement of the management of pediatric patients with HVA are urgently needed, and our analysis represents a relevant instrument in targeting a roadmap with this aim. The time for pediatric allergists to take action has come, and a task force from the Rare Allergic Diseases Commission of the Italian Society of Pediatric Allergy and Immunology is working on the topic to improve pediatricians' knowledge and optimize the care of these patients.

Large local reaction to Hymenoptera stings: Sound studies are needed to change a shared concept

The natural history of large local reactions to Hymenoptera stings allowed to estimate the risk to develop a systemic reaction after an initial large local reaction in about 4% of patients. A recently published study claimed that such risk concerns instead around one-fourth of patients. However, such study is flawed by serious imprecision, particularly the unreliable identification by patients of the culprit insect, as well as the dubious identification of the causative venom in multisensitized patients. Also, the authors criticized previous studied because of the limited number of patients, while they included in the study 662 patients. Indeed, when only patients clearly restung by the same insect according to their history data were considered, the number of patients fell to 35. These data are unable to change the current shared concept on the low risk of systemic reactions in patients with initial large local reaction.

Component-resolved diagnostics to direct in venom immunotherapy: Important steps towards precision medicine

Stings of Hymenoptera can induce IgE-mediated systemic and even fatal allergic reactions. Venom-specific immunotherapy (VIT) is the only disease-modifying and curative treatment of venom allergy. However, choosing the correct venom for VIT represents a necessary prerequisite for efficient protection against further anaphylactic sting reactions after VIT. In the past, therapeutic decisions based on the measurement of specific IgE (sIgE) levels to whole venom extracts were not always straightforward, especially when the patient was not able to identify the culprit insect. In the last years, the increasing knowledge about the molecular structure and relevance of important venom allergens and their availability as recombinant allergens, devoid of cross-reactive carbohydrate determinants, resulted in the development of an advanced component-resolved diagnostics (CRD) approach in venom allergy. Already to date, CRD has increased the sensitivity of sIgE detection and enabled the discrimination between primary sensitization and cross-reactivity, particularly in patients with sensitization to both honeybee and vespid venom. Hence, CRD in many patients improves the selection of the appropriate immunotherapeutic intervention. Moreover, the detailed knowledge about sensitization profiles on a molecular level might open new options to identify patients who are at increased risk of side-effects or not to respond to immunotherapy. Therefore, increasing potential of CRD becomes evident, to direct therapeutic decisions in a personalized and patient-tailored manner. Reviewed here are the state of the art options, recent developments and future perspectives of CRD of Hymenoptera venom allergy.

The high molecular weight dipeptidyl peptidase IV Pol d 3 is a major allergen of Polistes dominula venom

Hymenoptera venom allergy can cause severe anaphylaxis in untreated patients. Polistes dominula is an important elicitor of venom allergy in Southern Europe as well as in the United States. Due to its increased spreading to more moderate climate zones, Polistes venom allergy is likely to gain importance also in these areas. So far, only few allergens of Polistes dominula venom were identified as basis for component-resolved diagnostics. Therefore, this study aimed to broaden the available panel of important Polistes venom allergens. The 100 kDa allergen Pol d 3 was identified by mass spectrometry and found to be a dipeptidyl peptidase IV. Recombinantly produced Pol d 3 exhibited sIgE-reactivity with approximately 66% of Polistes venom-sensitized patients. Moreover, its clinical relevance was supported by the potent activation of basophils from allergic patients. Cross-reactivity with the dipeptidyl peptidases IV from honeybee and yellow jacket venom suggests the presence of exclusive as well as conserved IgE epitopes. The obtained data suggest a pivotal role of Pol d 3 as sensitizing component of Polistes venom, thus supporting its status as a major allergen of clinical relevance. Therefore, Pol d 3 might become a key element for proper diagnosis of Polistes venom allergy.

Component Resolved Diagnosis in Hymenoptera Anaphylaxis

PURPOSE OF REVIEW

Hymenoptera anaphylaxis is one of the leading causes of severe allergic reactions and can be fatal. Venom-specific immunotherapy (VIT) can prevent a life-threatening reaction; however, confirmation of an allergy to a Hymenoptera venom is a prerequisite before starting such a treatment. Component resolved diagnostics (CRD) have helped to better identify the responsible allergen.

RECENT FINDINGS

Many new insect venom allergens have been identified within the last few years. Commercially available recombinant allergens offer new diagnostic tools for detecting sensitivity to insect venoms. Additional added sensitivity to nearly 95% was introduced by spiking yellow jacket venom (YJV) extract with Ves v 5. The further value of CRD for sensitivity in YJV and honey bee venom (HBV) allergy is more controversially discussed. Recombinant allergens devoid of cross-reactive carbohydrate determinants often help to identify the culprit venom in patients with double sensitivity to YJV and HBV. CRD identified a group of patients with predominant Api m 10 sensitization, which may be less well protected by VIT, as some treatment extracts are lacking this allergen. The diagnostic gap of previously undetected Hymenoptera allergy has been decreased via production of recombinant allergens. Knowledge of analogies in interspecies proteins and cross-reactive carbohydrate determinants is necessary to distinguish relevant from irrelevant sensitizations.

Allergen-specific immunotherapy of Hymenoptera venom allergy - also a matter of diagnosis

Stings of hymenoptera can induce IgE-mediated hypersensitivity reactions in venom-allergic patients, ranging from local up to severe systemic reactions and even fatal anaphylaxis. Allergic patients' quality of life can be mainly improved by altering their immune response to tolerate the venoms by injecting increasing venom doses over years. This venom-specific immunotherapy is highly effective and well tolerated. However, component-resolved information about the venoms has increased in the last years. This knowledge is not only able to improve diagnostics as basis for an accurate therapy, but was additionally used to create tools which enable the analysis of therapeutic venom extracts on a molecular level. Therefore, during the last decade the detailed knowledge of the allergen composition of hymenoptera venoms has substantially improved diagnosis and therapy of venom allergy. This review focuses on state of the art diagnostic and therapeutic options as well as on novel directions trying to improve therapy.