The Spanish fly contains the highly toxic substance cantharidin, which destroys proteins, causes intestinal necrosis, and leads to multiple organ failure, with a mortality rate exceeding 50% among patients.
Dr. Nguyen Trung Nguyen from the Poison Control Center at Bach Mai Hospital in Hanoi reports that cases of Spanish fly poisoning are extremely severe. Most patients come into contact with this insect through the gastrointestinal tract, suffering from multi-organ damage and multi-organ failure.
Patients experiencing Spanish fly poisoning typically show signs of multi-organ damage, hypotension, and respiratory failure. Blood tests reveal severe acidosis, muscle damage, and renal and hepatic failure.
“The toxin in the Spanish fly is cantharidin, which is highly toxic and destroys proteins. Just 1 mg of cantharidin is enough to cause poisoning, and 10 mg can lead to death,” Dr. Nguyen stated.
Spanish fly.
The toxin secreted by the Spanish fly is similar to that of the three-segment ant. If it comes into contact with the hands and accidentally rubs the eyes, it can cause burning and corneal damage. Cantharidin entering the body through the digestive system causes severe poisoning, leading to stomach and intestinal damage, abdominal pain, vomiting, gastrointestinal bleeding, and intestinal necrosis.
Even direct skin contact, such as handling the insect with bare hands or inhaling the fumes from the opened container, can trigger severe allergic reactions, especially in individuals with thin skin or open wounds. The toxic fumes from the insect can cause a burning sensation in the eyes.
In recent years, the Poison Control Center at Bach Mai Hospital has received nearly a dozen patients suffering from severe Spanish fly poisoning. Recently, the center treated four members of a family from Thanh Hoa who were poisoned after consuming Spanish flies.
The four individuals had roasted and eaten winged insects they found on corn plants, unaware they were Spanish flies. About 20 to 30 minutes after consumption, they experienced throat pain, abdominal pain, vomiting, and bloody stools. The patients were rushed to the Thanh Hoa provincial hospital in critical condition, suffering from renal failure and metabolic acidosis, and were subsequently transferred to the Poison Control Center at Bach Mai Hospital. Two patients died shortly thereafter, while one suffered multiple complications such as renal failure, pneumonia, and hepatitis; only one person survived.
According to Dr. Nguyen, there is currently no effective treatment protocol for Spanish fly poisoning in the medical field worldwide. The actual treatment process depends on the available resources of the healthcare facility as well as the medical staff’s ability to provide resuscitation and the patient’s health condition. Treatment costs are very high, and most patients suffering from Spanish fly poisoning result in death.
The Spanish fly, scientifically known as Cantharis vesicatoria, is also referred to as the blister beetle. This species is a hard-winged insect, bright green in color, approximately 15-20 mm in length and 4-6 mm in width, with a heart-shaped head and a longitudinal groove in the middle, and black filamentous antennae. The body consists of 11 segments, with a constriction between the head and body. The upper part of the two black wings features yellow or light red spots; alternatively, the body can be yellow with black spots or stripes.
Dr. Nguyen warns that people should avoid catching Spanish flies to prevent poisoning and must never consume them. If exposed to Spanish flies and experience burning or blistering from the toxins, one should rinse the affected area with clean water, blink continuously, and then seek immediate medical treatment.
Spanish flies can be easily mistaken for stink bugs
Despite warnings, there are still annual cases of individuals being hospitalized due to consuming Spanish flies. Professor and Dr. Vu Quang Con from the Vietnam Entomological Society explains that when viewed from the side, Spanish flies have wings resembling a shaman’s robe, which is why they are sometimes referred to as “shaman insects.” There are many species of Spanish flies, but the most common is the black blister beetle. These insects are harmful to plants and contain a high level of toxins, which can cause skin blistering or burns, and in severe cases, can be fatal.
The Spanish fly contains lethal toxins that can be fatal if ingested.
Identifying Spanish flies is not difficult. They have a heart-shaped head, a longitudinal groove in the middle, and black filamentous antennae. The body is segmented into 11 parts, with a constriction between the head and body. The upper side of the two black wings has yellow or light red spots, or the body may be yellow with black spots or stripes. Spanish flies typically inhabit leguminous plants, which is why they are also known as “bean flies,” or they can be found on other toxic plants like belladonna.
To distinguish between Spanish flies and stink bugs, simply observe: if the stink bug has a triangular shape on its back and a proboscis, the Spanish fly does not. Spanish flies are typically black-bodied, with red heads. Due to their high toxicity, Spanish flies are sometimes used in traditional medicine as a treatment for various ailments.
Professor and Dr. Vu Quang Con states that species of Spanish flies all possess hard wings, bright green coloration, with lengths ranging from 15 to 20 mm and widths from 4 to 6 mm. Their heads are heart-shaped, with a longitudinal groove in the middle, and black filamentous antennae. The body consists of 11 segments, with a constriction between the head and body. The upper part of the two black wings features yellow or light red spots; alternatively, the body can be yellow with black spots or stripes.
