Pollination| Bumblebee stings |
| General
|
| In general, bumblebees are
peaceful insects and will only sting when they feel cornered or
when their hive is disturbed. When a bumblebee stings, it
injects a venom into its victim. Only female bumblebees (queens
and workers) have a sting; male bumblebees (drones) do not.
Contrary to a honeybee sting, the bumblebee sting has no barbs,
which means that a bumblebee can pull back its sting without the
sting detaching from its abdomen, thus a bumblebee can sting
several times. For most people, a bumblebee sting will only cause local swelling, but can cause an allergic reaction in some cases.
|
| Local reactions to a bumblebee sting |
| Bumblebee venom, like in wasp and
honeybee venom, contains certain substances that have a direct
effect on the blood vessels in the skin. Most people have a
local reaction with painful swelling, redness and itching around
the place of the sting. Sometimes, the swelling is really
pronounced, especially on parts of the body with looser skin,
such as the eyelids. Normally, the local reactions disappear
quickly but can last for a couple of days in some cases. A sting
in the mouth or throat can be dangerous because of the risk of
suffocation.
|
| Allergic reactions to a bumblebee sting |
| For some people, the body reacts
to the bumblebee venom through the production of IgE antibodies
against albumen structures in the venom. The presence of these
antibodies can be determined by a blood analysis. People who are
“positive” for the presence of IgE antibodies can show an
allergic reaction to the next bumblebee sting. The chance on an
allergic reaction to the first sting is usually very small
because no antibodies are present before the first sting.
An allergic reaction can manifest through a big to very big
local reaction. Sometimes, even an entire limb can be affected
in the reaction. Local reactions which are getting bigger can
sometimes precede a generalized allergic reaction. Generalized
allergic reactions (“anaphylaxis”) do not occur frequently and
are characterized by the appearance of symptoms on body parts
other than the one where a person was stung. The symptoms are
nettle rash with itching, and sometimes swelling of the face and
neck. It is possible that these symptoms can be accompanied by
unexpected intestinal complaints (e.g. vomiting and diarrhoea),
and/or dizziness, abundant sweating and cold shakes. The
respiratory system can also react; the allergic person could
feel a tickle in the throat with a cough reaction, or tightness
in the chest and squeezed throat with difficulty in breathing as
a consequence. In serious cases, the heart and vascular system
can also react: drop in blood pressure, loss of consciousness
and anaphylaxis shock may occur. A general reaction manifests
within 30 minutes after the sting. Allergic reactions have the
tendency to become more serious by repetition; i.e. that an
allergic person will have more serious reaction with every new
sting.
|
| Cross-reaction with honeybee venom |
| Because bumblebee and honeybee
venom contain similar albumen structures, some people are
sensitive to bumblebees as well as to honeybees. This phenomenon
is called a cross-reaction.
|
| Interactions of medecines |
| Some medicines (e.g. medicine
against high blood pressure (beta-blocker), ACE-inhibitors, and
aspirin) can strengthen the allergic reaction. People with
greater chance to get stung should avoid the use of such
medicines. After a bumblebee sting, it is advised to avoid
alcoholic drinks and heavy physical efforts.
|
| Prevention of bumblebee stings |
| Do not provoke aggressive
behaviour of bumblebees: do not disturb bumblebees, do not hit
bumblebees which are flying in your direction, use bumblebee
hives correctly, do not bump against hives, and avoid perfumed
smells.
|
| Treatment of a local reaction |
| Local reactions can be relieved
with ice put on the place of the sting. Creams also exist, but
these have little effect. Antihistaminic tablets (such as
Claritine, Aerius, Zyrtec, Xyzall, Estivan, Mizollen or Telfast)
are effective to some extent. These tablets will also favourably
influence a possible allergic reaction. In case of a sting in
the mouth or throat, an emergency admission in the hospital is
necessary.
|
| Treatment of allergic reactions |
| It is important to remain calm
when you have or are suspecting you are having an allergic
reaction. Panic shall only worsen the reaction. Call a doctor as
soon as possible, and depending on the seriousness of the
reactions call a medical urgency group if necessary and explain
clearly what has happened. If you feel dizzy, the best thing to do is to lie down on your back with the legs up. General reactions are treated with injections of adrenaline, antihistaminica and cortico-steroids. If breathing problems occur, an adrenaline-inhalator or an adrenaline-injection can be used. Heart and vascular system problems must be treated as soon as possible in the hospital.
|
| Desensization cure |
| If you had a generalized allergic
reaction to a bumblebee sting, it is possible to follow a
desensitization cure. During such a cure, the body is
progressively made accustomed (insensitive or tolerant) to the
bumblebee venom. This cure must be followed in a specialized
centre. In Belgium and The Netherlands there are expertise
centres for bumblebee venom allergy and immunotherapy.
For more information on centres in your area, you can contact your company or family doctor.
|
| Conclusion |
| An allergic reaction to bumblebee
venom is rather rare. Nevertheless, it requires necessary
attention because of the possible seriousness of such reaction. Following preventive measures are recommended:
It is also advised to carry an adrenaline-injector (Epipen; ALK) or adrenaline injection ampoules (Adrenaline Denolin) with you or to keep it within reach so that you can inject yourself in case of emergencies.
|
| Acknowledgement |
| Hereby I would like to thank Dr. H. de Groot (Erasmus MC), Dr. A.-M. Kochuyt (UZLeuven) and Dr. W. Stevens (UZAntwerpen) for their valuable remarks and suggestions. |