Bee attacks increase in Brazil, exposing lack of antidote

Known for their role in honey production and plant pollination, Africanized honeybees ( Apis mellifera ) may seem harmless with their yellow coloring and frequent flower visits. But when threatened, they can pose real risks to human health—especially if they are accompanied by other members of their hive and form a swarm.

Data from the epidemiological panel on accidents involving venomous animals , maintained by the Ministry of Health, indicate that 34,260 people reported episodes involving bee attacks in the country in 2024, 117 of which resulted in death. This represents an 82% increase in the total number of reports of such cases compared to 2020 (18,818), as well as a 56% increase in deaths (75).

According to veterinarian Rui Seabra Ferreira Júnior, a professor at São Paulo State University (Unesp), this phenomenon may be a consequence of Brazil's rise in honey and honey-derived products production in recent years, spreading the insect's breeding across the country. Furthermore, climate change may have favored the species' occurrence in areas where it was previously uncommon.

Today, bee attacks rank third among animal-related poisonings, behind only scorpions and spiders, respectively. Since 2023, bee attacks have even surpassed snake emergencies. "This is a public health problem that is often overlooked," emphasizes Ferreira Júnior, who also serves as director of the Center for the Study of Venoms and Venomous Animals (CEVAP).

He and his team discussed the potential clinical complications of bee sting toxin in a paper published in September 2024 in the journal Frontiers in Immunology . The study draws particular attention to the lack of a specific antidote to treat the condition, as is the case with other venomous animals.

Lack of specific treatment

Hospital treatment for bee attacks is supportive, meaning care focuses on alleviating symptoms through medication and maintaining life in more severe cases. Mild and moderate allergies are treated with antihistamines, topical corticosteroids, and simple analgesics, while severe cases, with systemic manifestations or anaphylaxis, require epinephrine. It's worth remembering that there are no antidotes available for bee venom—like antivenom, antiscorpion, or antiarachnid serums used to treat other venomous animals.

The production of a bee antivenom has been tested worldwide in recent decades. However, there is a major challenge to achieving this goal: the process of developing a serum, which involves administering this venom to an animal (usually a horse), has presented problems due to the pain this toxin causes. The physical discomfort directly affects antibody production, making the development of a serum from these proteins unfeasible.

"It was only more recently that our group was able to identify and remove, through the application of biotechnological tools, all the components that cause pain and allergy in this venom, leaving only its toxic components," reports Ferreira Júnior. "Without the pain, the horses began to produce highly responsive antibodies."

From this, his team, in conjunction with the Butantan Institute and the Vital Brazil Institute, managed to obtain a novel candidate to advance the production of an Africanized bee antivenom serum (which the researchers named apilic antivenom). Details of a phase 2 clinical trial with the product were published in March 2021 in the journal Frontiers in Immunology .

It found that the 20 patients involved showed significant clinical improvement after administration of the antivenom, with clinical parameters returning to normal within 30 days. This was true even among people attacked by swarms of more than 500 bees.

Regarding safety, no serious adverse events related to the use of antivenom were observed. Only two patients experienced early, mild adverse reactions, such as itching, hives, and lip numbness, which were controlled without the need to discontinue treatment.

"Our proposal for a phase 3 clinical trial with more volunteers is currently being evaluated by the Ministry of Health. These results could allow us to file a registration request with the National Health Surveillance Agency (Anvisa) and, subsequently, distribute it through the Unified Health System (SUS)," notes the Unesp professor. "If all goes as planned, it will be a world-first drug, which Brazil could even export to other countries."

When to seek professional help?

Those most vulnerable to attacks tend to be those living near apiary areas. It's relatively common for very large and populous hives to experience a swarming process, in which a new queen emerges and departs to form a hive in a new location, accompanied by some drones and worker bees. During this migration, the swarm may temporarily settle in houses and fallen logs, where they can attack in an attempt to protect their food and offspring.

"When we talk about bee stings, we basically need to think about two critical scenarios: one in which the patient knows they are allergic to the stings and, therefore, may have a serious allergic reaction (anaphylaxis); or one in which the person has been stung by several bees, usually more than 50, and a larger amount of venom has been injected," explains emergency physician Gustavo Fernandes Moreira, coordinator of the Goiás Emergency Hospital (HUGO), in Goiânia, a unit managed by Einstein Hospital Israelita.

In the case of isolated stings, it's common to see localized allergic reactions on the skin within a five-centimeter radius of the sting. The area may be red and swollen, tender, and painful. Unless the individual has a history of allergies, these conditions can usually be treated at home, without the need for a visit to a medical center.

However, if the area of ​​swelling and redness exceeds ten centimeters in diameter and is associated with more complex symptoms, such as very intense pain that does not improve with painkillers, it is recommended to seek professional help at an emergency department. According to experts, there is a risk of this being a case of venom sensitivity. It is estimated that approximately 8% of the world's population is allergic to some type of bee venom.

Symptoms of anaphylaxis include the appearance of red, raised patches on the skin outside the immediate area of ​​the bite, difficulty breathing, swelling of the tongue, lips, eyelids, and other mucous membranes, severe abdominal pain, fainting, diarrhea, and vomiting. These effects can occur quickly.

In turn, envenomation by swarm attacks can lead to slower, more gradual clinical symptoms that must be treated by healthcare professionals in emergency centers. These symptoms include itching, redness, generalized heat, the appearance of lumps on the skin, low blood pressure, tachycardia, headache, nausea, and abdominal cramps. If not treated properly, it can also lead to respiratory failure, muscle tissue degradation, and kidney damage.

Attack prevention

Until an effective antivenom against bee stings is available, the best way to prevent complications is to avoid high-risk areas. Since most accidents occur when encountering a swarm, it's recommended that, if this occurs, the person leaves the area quickly.

Running in a zigzag pattern may be better than running in a straight line, as studies suggest that bees have some difficulty making sudden changes in direction. It's important to remember that you don't need to run a long distance, as bees only want to protect their home, and they're unlikely to chase an individual more than a few meters away from the hive.

In urban areas, if you spot a hive forming in a home, you should contact municipal authorities to deal with the problem, including the fire department, the zoonosis department, and the health security agency. Using insecticides can irritate the bees, as can loud noises and movement near the nest.

If you're bitten by these insects, try to remain calm, avoid sudden movements (which attract other bees to attack), and seek shelter in a closed area, away from the hive. Especially in cases of multiple stings or an allergic reaction, seek immediate medical attention, calling the Mobile Emergency Care Service (SAMU) at 192 if necessary.

"Removing the stingers within the first minute after stinging can reduce the amount of venom injected into the body. This can be done with firm tools that allow you to scrape the skin, such as a card," Moreira notes. "After the first minute, much of the venom in the stinger reservoir has already been injected, so this is no longer a priority."

In any case, the stingers will be removed by doctors at the hospital once other more urgent situations are under control. This step is important to avoid a delayed secondary allergic reaction to the stinger itself, not the venom.

Finally, it's worth noting that anyone who's going to help someone attacked by bees must also take certain precautions. "Before going to the victim, the rescuer must check whether it's safe to intervene at that moment, otherwise, instead of one patient, we'll end up with two," concludes the Einstein doctor.

Source: Einstein Agency

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