Africanized Honey Bees: Apis
mellifera scutellata
In 1956, scientists in Brazil were
looking for a way to increase honey production made by the local
bees. As part of their experiment they imported honeybees from Africa
and to their surprise some of the imported bees managed to escape and
began mating with the local honeybees. The result was a hybrid cross
between two species of bees, which were named the “Africanized
honeybee”. These hybrid bees proved to be aggressive and dangerous.
They were soon referred to as “Killer bees” because their stings
had the ability to kill humans. Since 1990 scientists estimate that
there have been at least 17 deaths in the United as a result of a
Killer bee envenomation (KOLECKI, 1998). In another study involving a
small group of patients the cause of death following honeybee stings
was respiratory failure.
Clinical studies of Apis Mellifera
have shown that many who encounter their potential fatal sting do not
survive. The prevalence of this insect is rather high in Brazil as
well as many other countries including the U.S. and due to their
aggressive nature they are a concern for public safety. There are
clinical cases of patients who have survived numerous Africanized bee
stings, however they did suffer physically. Clinical manifestation of
the bee toxin was characterized by diffuse and wide spread edema, a
burning sensation in the skin, weakness, dizziness, and hypotension.
Acute renal failure also developed and was attributed to hypotension,
intravascular hemolysis and myoglobinuria due to the direct toxic
effect of the massive quantity of injected venom (KOLECKI, 1998).
It has also been observed that
multiple Africanized bee stings can cause death in adults. Case
reports of people who had been stung by the Africanized bee indicated
that even healthy adolescents were likely to experience muscular
weakness, diffuse edema, general paresthesia, nausea, vomiting and
loss of consciousness (DAHER et al., 2003).
Clinical research has suggested
that systematic toxic effects of bee venom are generally seen on
patients who have at least 50 stings. The potentially lethal number
of stings is estimated to be about 500, with death occurring due to a
direct systemic effect of the venom due to a large amount of toxin
flowing through the body (KOLECKI, 1998).
The bee's venom contains toxins such as mellitin, which if the main component and has hemolytic and vasoactive properties, it is analogs to the C9 component of the complement cascade and it is able to metabolize the arachidonic acid; phospholipase A2, it is the most active component within the animals venoms, it has myotoxic action; biogenics amines, it is involved with signalization of systems such as immune and nervous; hyaluronidase, degrades the extracellular matrix.
It also contains apamin, a
neurotoxin which could contribute to the lysis of red blood cells and
leukocytes (ERLER et al., 2011). The Africanized bee stings are
particularly interesting because even after the stinger is detached
from the insect body it continues to inject venom because the long
sting shaft remains inside the skin. This poses concern for the
complete and effective removal of the stinger because it is possible
for a portion of the stinger to remain inside the body and continue
to release venom. Relative mortality rates from insect bites and
stings have been estimated from several case studies and it is
assumed to be between 15-25% (DAHER et al., 2003).
References:
Daher, E., Silvia-Junior, G., Bezerra, G., et al. 2003. Case Report: Acute Renal Failure After Massive Honeybee Stings. Rev. Inst. Med. Trop. Säo Paul. Vol:45 (1) 45-50.
Erler, S., Lommatzsch, S., and Lattorff, H.M.G. 2012. Comparative analysis of detection limits and specificity of molecular diagnostic markers for three pathogens in the key pollinators Apis mellifera and Bombus terrestris. Parasitology Research. Vol:110 (1) 1403-1410.
References:
Daher, E., Silvia-Junior, G., Bezerra, G., et al. 2003. Case Report: Acute Renal Failure After Massive Honeybee Stings. Rev. Inst. Med. Trop. Säo Paul. Vol:45 (1) 45-50.
Erler, S., Lommatzsch, S., and Lattorff, H.M.G. 2012. Comparative analysis of detection limits and specificity of molecular diagnostic markers for three pathogens in the key pollinators Apis mellifera and Bombus terrestris. Parasitology Research. Vol:110 (1) 1403-1410.
Kolecki, Paul. 1999. Delayed Toxic
Reaction Following Massive Bee Envenomination. Annals of Emergency
Medicine. Vol:33 (1) 114-118.