Bees and wasps provide an important service to ecosystems, contributing to the improvement of biodiversity while helping to maintain ecological balance. Although not frequent, hornet, wasp, and bee stings may be life-threatening. With each sting, Hymenopterans inject a small amount of venom that can cause reactions of varying intensity: (i) normal local reactions (NLR), (ii) large local reactions (LLR), (iii) systemic anaphylactic reactions (SAR), (iv) systemic toxic reactions (STR) and (v) unusual reactions (UR). Hymenopteran stings have recently become a worldwide public health concern. However, this health problem can be underestimated despite the number of cases presented. With the expansion of non-native Hymenopteran species across Europe, allergists should be aware that their community’s exposures are continually changing. In this way, the invasive Vespa velutina was identified as responsible for three-quarters of the Hymenoptera anaphylaxis patients reported during the last years in north-western Spain.
1. Introduction
Anaphylaxis is an acute, life-threatening reaction that occurs shortly after contact with a trigger. It is classically defined as the most severe form of an allergic reaction, but it could also be induced by non-IgE-mediated pathways through the activation of mast cells and basophils through different mechanisms
[1]. Common triggers of anaphylaxis include foods, drugs, venoms from insects, general anaesthetics, radiocontrast agents, and latex, among others, and their prevalence varies from region to region being different for each patient group
[2].
The medically important groups of the Hymenoptera order in Europe are those of the genus
Apis and
Bombus (belonging to the family Apidae), and
Vespula, Dolichovespula, Vespa and
Polistes (family Vespidae)
[3]. Social Apidae, Vespinae and Polistinae possess a large and comprehensive array of venom components
[4]. Hymenoptera venoms are composed of a mixture of biologically active proteins and peptides, some of them common to different species such as phospholipases, hyaluronidase, phosphatase, α-glucosidase, serotonin, histamine, dopamine, noradrenaline, and adrenaline. Other proteins such as melittin, apamin, and the mast cell degranulating peptide are exclusive to bees, while mastoparan and bradykinin are only found in wasps
[5,6,7,8,9,10][5][6][7][8][9][10]. As a rule, Hymenoptera species are not especially predisposed to attack humans; however, social hornets, wasps, and bees have developed a protective response to whatever risk the colony faces through stings.
With each sting, Hymenopterans inject a small amount of venom that can cause reactions of varying intensity: (i) normal local reactions (NLR), (ii) large local reactions (LLR), (iii) systemic anaphylactic reactions (SAR), (iv) systemic toxic reactions (STR) and (v) unusual reactions (UR)
[11]. The local reaction is limited to the area of the sting and is usually small in size, with redness, swelling and intense pain. If a person has a reaction area of the sting of greater than 10 cm, it may mean that he or she has been sensitized, but, as a rule, it does not need any special action. SAR reactions are those that cause symptoms beyond the point of the sting and can range from skin lesions to respiratory problems, digestive symptoms or anaphylaxis. The prevalence of SAR in Europe due to Hymenoptera stings ranged between 0.3 and 7.5% in adults and is slightly lower in children (0.15–3.4%)
[12]. STR occur due to multiple Hymenoptera stings because of the well-known toxic properties of their venoms. The symptomatology of UR differs from typical allergic reactions, and, in some cases, follow-up is required over many months
[13].
Some authors indicated that 94.5% of humans are stung by
Hymenoptera insects at some point in their lifetime
[14]. Although most of these stings are not reported, general practitioners attend to a large number of patients with Hymenoptera stings, and a few of them require rapid assistant at emergency departments. Thus, in USA, it was estimated that 220,000 annual visits are made to the emergency department and nearly 60 deaths occur per year due to Hymenopteran stings
[15]. In addition, an analysis of 4000 cases of anaphylaxis from Germany, Austria and Switzerland, show insect venom (
n = 2074; 50.1%) as a common trigger of anaphylaxis
[2]. For these reasons, researchers highlight that an effective and affordable treatment for anaphylaxis caused by these arthropods is critical.
Hymenopteran stings have recently become a worldwide public health concern
[16,17][16][17]. However, this health problem can be underestimated despite the number of cases presented. Realistic mortality epidemiological data are still lacking in some countries
[18]. Information on the incidence of fatalities due Hymenoptera stings is crucial for an assessment of the problem, as well as to enhance medical assistance for patients and creating public policies aimed at decreasing the incidence of these events
[19,20][19][20]. More than half of the people with fatal sting reactions had no preceding anaphylactic episodes
[21,22][21][22].
According to chapter XX of the International Classification of Diseases and Related Health Problems 10th Revision (ICD-10) fatalities due to hornet, wasp and bee stings (including yellow jackets) are coded as X23
[23]. The worldwide incidence of insect-sting mortality ranged from 0.03 to 0.48 fatalities per 1,000,000 inhabitants per year, which is low but not negligible
[21].
2. Hymenopteran Sting-Related Deaths
During 1994–2016, a total of 1691 deaths were officially registered in Europe with code X23. Fatalities were confirmed in 28 countries, with Germany (
n = 327, 19.3%), France (
n = 211, 12.5%) and Romania (
n = 149, 8.8%) reporting the highest numbers (
Table 1). A total of eleven countries (BG, FR, DE, EL, IT, PL, RO, RS, ES, CH and UK) report deaths every year. FR, DE, EL, PL and RO, had the minimum number of such deaths. At least one sting-related death occurred yearly in the following six countries: BG, IT, RS, ES, CH and UK. In the rest of the countries (
n = 17), deaths due to stings of Hymenoptera insects are not always present. The maximum values of the number of annual deaths for the different countries, varied, ranking as: DE (32), FR (23), RO (16), CZ (14), HU (13); and AT, IT and FL (12). The range of deaths varies from country to country, at it is interesting to highlight the following: DE (range = 26); CZ, FR and RO (range = 14); HU (range = 13); AT (range = 12) and IT (range = 11).
Table 1. Descriptive statistics of fatalities due to hornet, wasp and bee stings by country (1994–2016).
Country 1 |
Size |
Sum |
Minimum |
Maximum |
Range |
Mode |
Mean |
Median |
Standard Deviation |
Variance |
AT |
15 |
73 |
0 |
Deaths12 |
Total |
540 |
171 |
25612 |
5 |
4.87 |
5 |
3.27 |
10.7 |
724 |
1691 |
BE |
18 |
27 |
0 |
| 5 |
5 |
1 |
1.5 |
Men | 1 |
1.42 |
2.03 |
425 |
| (78.7%) |
BG |
9 |
26 |
1 |
6 |
5 |
2 |
2.89 |
2 |
1.62 |
2.61 |
HR |
19 |
35 |
0 |
6 |
6 |
1 |
1.84 |
1 |
1.71 |
2.92 |
127 |
| (74.3%) |
223 | (87.1%) |
545 (75.3%) |
1320 (78.1%) |
|
Woman |
115 (21.3%) |
44 (25.7%) |
33 (12.9%) |
179 (24.7%) |
371 (21.9%) |
Ratio |
X23GR |
3.7 |
2.9 |
6.8 |
3 |
3.6 |
CZ |
23 |
111 |
0 |
| 14 |
X23GD |
310 |
83 |
19014 |
4 |
4.83 |
4 |
3.04 |
9.24 |
366 |
949 |
EE |
17 |
14 |
0 |
3 |
3 |
0 |
0.82 |
1 |
1.01 |
1.03 |
Age |
≤14 years |
3 (0.6%) |
- |
2 (0.8%) |
3 (0.4%) |
8 (0.5%) |
FI |
20 |
25 |
0 |
4 |
4 |
0 |
|
15–24 years |
10 (1.9%) |
1 (0.6%) |
3 (1.2%) |
7 | 1.25 |
| 1 |
(1%) |
21 (1.2%)1.25 |
1.57 |
FR |
15 |
211 |
|
25–64 years |
418 | 9 |
23 |
(77.4%) |
101 (59.1%)14 |
169 (66%) |
440 (60.8%)14 |
14.07 |
14 |
1128 (66.7%)4.15 |
17.21 |
DE |
18 |
327 |
|
≥65 years |
109 | 6 |
32 |
(20.2%) |
55 (32.2%)26 |
18 |
18.17 |
18 |
826.97 |
48.62 |
| (32%) |
274 |
| (37.8%) |
520 | (30.8%) |
EL |
2 |
9 |
4 |
5 |
Place | 1 |
Not reported |
33 (6.1%) |
52 | 4 & 5 |
| 4.5 |
4.5 |
(30.4%) |
73 (28.5%) |
1 (0.1%) |
159 (9.4%)0.71 |
0.5 |
HU |
21 |
112 |
0 |
13 |
13 |
4 |
5.33 |
4 |
|
X23 code extension to four-digit reported | 3.54 |
5 |
507 | 12.53 |
| (93.9%) |
119 | (69.6%) |
183 (71.5%) |
723 (99.9%) |
1532 (90.6%) |
IE |
8 |
2 |
0 |
1 |
1 |
0 |
0.25 |
0 |
0.46 |
0.21 |
|
X23.0 (home) |
241 (44.6%) |
35 |
IT |
13 |
69 |
1 |
12 |
11 |
5 & 3 |
5.31 |
5 |
3.4 |
11.56 |
LV |
9 |
9 |
0 |
2 |
2 |
2 |
1 |
1 |
1 |
1 |
| (20.5%) |
19 |
| (7.4%) |
202 (27.9%) |
497 (29.4%) |
|
X23.1 (residential institution) |
5 (0.9%) |
1 (0.6%) |
- |
2 (0.3%) |
8 (0.5%) |
|
X23.2 (school, other institution and public administrative area) |
5 (0.9%) |
- |
1 (0.4%) |
1 (0.1%) |
7 (0.4%) |
LT |
7 |
7 |
0 |
4 |
4 |
1 & 0 |
1 |
1 |
1.41 |
2 |
|
X23.3 (sports and athletics area) |
1 (0.2%) |
- |
- |
- |
1 (0.1%) |
LU |
7 |
1 |
0 |
1 |
|
X23.4 (street and highway) |
17 (3.1%) |
1 | 1 |
(0.6%) |
6 (2.3%) |
30 (4.1%)0 |
0.14 |
0 |
540.38 |
0.14 |
(3.2%) |
NL |
21 |
20 |
0 |
5 |
5 |
0 |
0.95 |
1 |
1.2 |
1.45 |
|
X23.5 (trade and service area) |
- |
- |
- |
- |
- |
NO |
20 |
19 |
0 |
3 |
3 |
1 |
|
X23.6 (industrial and construction area) |
1 (0.2%) |
- | 0.95 |
1 |
0.76 |
- |
- |
1 | 0.58 |
| (0.1%) |
PL |
17 |
125 |
3 |
12 |
9 |
7 & 8 & 9 |
7.35 |
8 |
2.67 |
7.12 |
|
X23.7 (farm) |
18 (3.3%) |
1 (0.6%) |
6 (2.3%) |
1 (0.1%) |
26 (1.5%) |
PT |
13 |
9 |
0 |
4 |
4 |
0 |
0.69 |
0 |
|
X23.8 (other specified place) |
48
| 1.32 |
(8.9%) |
9
| 1.73 |
(5.3%) |
21 |
| (8.2%) |
112 | (15.5%) |
190 (11.2%) |
RO |
18 |
149 |
2 |
16 |
14 |
10 |
8.28 |
|
X23.9 (unspecified place) |
171 (31.7%) |
72 (42.1%) |
130 (50.8%) |
375 | 9 |
| 3.44 |
11.86 |
(51.8%) |
748 |
| (44.2%) |
RS |
18 |
53 |
1 |
6 |
5 |
3 |
2.94 |
3 |
1.43 |
2.06 |
SK |
21 |
17 |
0 |
2 |
2 |
0 |
0.81 |
1 |
0.81 |
0.66 |
SI |
19 |
21 |
0 |
4 |
4 |
0 |
1.11 |
1 |
1.37 |
1.88 |
ES |
17 |
60 |
1 |
8 |
7 |
4 & 3 |
3.53 |
3 |
1.81 |
3.26 |
SE |
20 |
44 |
0 |
6 |
6 |
1 |
2.2 |
2 |
1.61 |
2.59 |
CH |
21 |
65 |
1 |
8 |
7 |
4 |
3.1 |
3 |
1.61 |
2.59 |
UK |
15 |
51 |
1 |
7 |
6 |
2 |
3.4 |
4 |
1.84 |
3.4 |