LONOMIA OBLIQUA: The Killer Caterpillar
Some of the most potent insect venom anywhereClick thumbnail to view full-size
There's Much in the Rain Forest Undiscovered
LONOMIA, the Killer Caterpillar
This is an interesting letter I have just received from an actual victim of the caterpillar and added to article. I thought it so germane to the danger of Lonomia to head the hub with the report.
"My name is Marianne: I am still interested in publications about the Lonomia Obliqua caterpillars that are found in Brazil and some other South American countries. Three years ago I was a victim of this caterpillar poisoning, ending up with haemolysis and acute kidney injury while in Brazil, after visiting Iguassu Falls. I accidentally touched a tree with my left hand and this resulted in a painful rash and swelling thereafter. I took a photograph for identification in case I had contracted something unfamiliar. It took another 3 days before I requested medical attention as the initial symptoms had cleared after a few hours.
Luck was on my side as I attended a medical conference and my local medical colleagues saved my life as they were able to contact the local public health office who then arranged for the antivenin to be delivered to the hospital I was admitted to obtain urgent medical advice .I like recommend the following website to anyone who may have been affected by a similar accident: www.cit.sc.gov.br This is the poisons unit of the Butantan Institute in Sao Paolo"
Full name withheld by author. Very sensible idea to capture an offending insect, or, in this case, to take photos of it.
We have known for ages many caterpillars can cause irritation by discharging body hairs, or can defend themselves by releasing vile-smelling secretions. Some are even known to be poisonous if ingested, along with the butterflies and moths they spring from. But until Lonomia came along we had not been exposed to a caterpillar able to release such catastrophic toxins that they could easily kill us.
Humans and Lonomia first attracted international press when an epidemic occurred amongst an agrarian community in Rio Grande du Sol, Brazil. Medicos were mystified at first after they received a score of patients with the same symptoms: haematoma and gangrene-like symptoms, spreading throughout the body, eventually causing massive blood leakage into the brain and, in several cases, death.
Snakebite, arachnids or giant centipedes were suspected at first, but no obvious bite sites were found and no patients reported being struck or bitten by one of the many venomous reptiles or insects in the rainforest. But gradually a picture emerged of people saying they had “just handled a bunch of leafy branches to break trail, or to gather vegetation for fires and shelter.” Doctors cautiously exploring the territory they had mentioned came across only one creature than commonly appeared, the Lonomia Caterpillar.
On examination, this curious caterpillar camouflaged itself by means of many plant-like hair-growths all over its body. (see last pic). Each tiny clump of hairs had a sharp, cactus-like spine sticking out which easily and painlessly punctured the skin of a human or predator that touched it. They had found the mysterious assassin…just a caterpillar.
Further studies isolated the agents in the toxins contained in a sack at the base of each spine. It was one of the strongest anti-clotting agents ever found in nature. Along with another protein which attached itself to the surface of the body’s cells, this caused all the body’s cells to leak like sponges as the blood was unable to clot, until the surrounding tissue was full of “bruised” blood; huge haematomas spread over the surface and the interior organs of the body as well as, eventually, the brain causing massive compression and brain death. In fact, more recent statistics reveal as many as 500 people or more have died as a result of coming into contact with Lonomia.
The investigators also found that the caterpillars were only dangerous if seized in numbers - rather like grabbing stinging nettles, or becoming a victim to the venomous spines of box jellyfish. To produce the deadly haematomas the victim would need from about 20 to 100 “stings” from the spines. Further, they found the caterpillars only appeared from two to three months of each year. As the symptoms could take a week or two to become serious, this is why the creatures had not been detected earlier; by the time someone was struck down, the caterpillars had ceased to feed on plants and had become pupae, disappearing from under investigator‘s noses.
An antivenin is now available, which has reduced the numbers seen in the clinics each season by more than one half. It was made by injecting horses with the toxin and drawing off the resistant cells to prepare the medicine. (I am unclear of the exact procedure, sorry). It has taken many thousands of caterpillars to make the vaccine each year, but the creature has made the most dangerous lists of world health authorities resulting in foreign doctors and health workers going to the area to help.
Most scientists think there are many other creatures “out there” waiting to be discovered with the potential to do harm and cause death to unwary humans straying in the environment. There are almost certain to be more venomous caterpillars, as they have not been seen as an extreme threat until recently and little is known about them as a whole. The evidence from my limited research to do this article is that there may be literally hundreds of venomous caterpillars around the world, several of which can do serious harm to man, especially if he is at all allergic to the toxins released when their spines are touched. The Lonomia family seem to be the worst, but there are some in the Southern USA, Mexico and the Americas, such as the so-called "Slug" caterpillars: Saddleback, Hag, Lo Moth and, the worst, Puss Moth. In fact the last moth larvae has caused several people to be taken to hospital with symptoms similar to Lonomia, although they don't result in death. The Hag caterpillar doesn't look like what we usually see, but looks more like a slow-moving arachnid or large tick. It is true to say moth and butterfly larvae, as a whole, remain virtually unknown and ignored.
This caterpillar is an attractive creature to look at, as so many poisonous and venomous life forms are: some because they want to advertise their presence in order to be left alone, and others which instinctively believe their reputation precedes them in the wilderness and are not likely to be molested, except by a hairless, weak, insensitive animal that has lost all remnants of jungle lore and survival it once possessed and knows no better. We all know who that is!
One thing about living in bland old Britain, we have few really nasty, venomous creatures to worry about, Peter Mandleson excepted.
Notes : The larvae, or caterpillar, from the family Saturnadae, are covered in urticating hairs (cause irritation and small pustules) as are many caterpillars. The LD50 of the toxin is about equal to some rattlesnakes. There are 12 or more species known at present, mostly in Brazil and Venezuela (Lonomia Achelous is more common in Venezuela as well as Obliqua). The anticoagulant properties are currently being explored by the pharmaceutical industry for use in human blood clotting problems. The toxin has also been responsible for kidney failure in some patients.