Amidst the raging pandemic and the black, white fungus outbreaks, a new health threat has come up. Over the past few weeks, local residents in Kakkanad in Kerala's Ernakulam have been facing distress due to insects belonging to the blister beetle family. Here is everything we know so far about the insect that has become a cause of concern.
1. What are blister beetles?
Blister beetles, sometimes called acid flies, belongs to the Meloidae family of beetles that secretes toxic Cantharidin -- an odourless, colourless fatty substance. There are over 7,500 species of blister beetles on earth and the insects display aggressive behaviour and move towards sources of light at night.
2. Why are blister beetles harmful?
Cantharidin is classified as an extremely hazardous substance and can cause severe damage to the lining of the gastrointestinal and urinary tracts. It may also cause permanent renal damage if consumed.
The cantharidin concentration will vary by species, size and sex of the blister beetle. Male blister beetles will have more cantharidin concentration in their bodies than females.
3. What do blister beetles do to the human body?
The health condition caused by the toxin is called Paederus dermatitis or blister beetle dermatitis that can even burn off human skin in some conditions. Cantharidin causes bubbles and itching on the skin. It has the potential to cause severe damage to human skin if left unattended.
4. Where are blister beetles found?
The insects are commonly found in buildings located close to forested areas and plantations where fallen leaves were left to decay. Thick bushes and the growth of grass following the arrival of the monsoon attract the beetles who later mate and lay eggs. Wooden roofs of the building are also preferred by the insects, especially in old houses.
5. What do blister beetles look like?
They have moderately long antennae and legs while colour and size vary by species. The commonly found acid flies in Kerala are around 8mm in height and 1.2 to 2 mm in width. The beetles have long, cylindrical, soft bodies with heads wider than the pronotum -- the plate-like structure that covers part of its thorax.
6. Why the menace now?
It is on the surface layer of soil where the leaves decay during the rainy season, the months of June and July in particular, that the beetles like to breed.
7. What can be done to avoid blister beetles?
Since blister beetles are aggressive in behaviour and are attracted by light, it is advised to shut windows and doors by sunset. If the insect is spotted in your locality, using mobile phones after dimming all lights around in a closed environment is risky as they might fly towards the active phone display and land on the user.
8. How is acid fly attack treated?
Clinical diagnosis is carried out to find out the cause of the blister. Topical steroids may be needed for some patients, while oral antibiotics along with creams are prescribed in other cases.
If the beetle touches a person's body, reports suggest he/she should not slam it dead or strike it in any manner. It is best to try and shake it off the body and immediately wash the affected area using soap and water. In case of contact in or around the eye(s), the person should wash his eyes and face in water multiple times and seek medical attention.
9. What else do we know about Cantharidin?
In countries like the US, acid flies cause constant trouble among farmers as cattle and horses are very sensitive towards their cantharidin secretion. During the breeding season, the beetles get trapped in heys and bushes cut to feed the animals. Dead or alive, cantharidin remains in the insect's body and contaminates the hay which is later consumed by the animals. While internal consumption is lethal, external exposure causes damage to body tissues.
10. What is the solution?
The identification of breeding spots is important to control the population of the insect.