Scratch, scratch, scratch, goes the fingers on the leathery skin around the neck. The itchiness can be distressing. A burning sensation is followed by a patch of dermatitis and blistered skin.

Is this what you experienced? You were most likely a victim of Nairobi Fly.

Nairobi Fly is not a flattering attribute to the city. This fly is the cause of so much discomfort and pain to any who has had the unpleasant opportunity to cross paths with it. It is synonymous with Kenya than any other part of the world. The Journal of Entomology refers to it as Kenya Fly or Nairobi Eye.

But what exactly is the Nairobi Fly and what dangers does it pose?

In 1998 and 2007, there were outbreaks of the Nairobi Fly, particularly due to heavy rains (specifically El Niño), which create favourable conditions for the fly to thrive.

There are two species of the Nairobi Fly (which is actually a beetle), scientifically known as Paederus eximius and Paederus sabaeus.Marked distinctly by black and red stripes and about six to10 mm long, the insects live in rotting leaves where they lay their eggs and breed.

According to the Archives of Entomology, Nairobi Fly does not sting or bite. However, the insect’s body is engorged with haemolymph (a type of liquid that makes up the body of insects), which contains pederin, a potent toxin that causes blistering and dermatitis.

Burning sensation

When the toxic liquid comes into contact with the skin, it causes itching or a burning sensation, which eventually leads to swelling. The effects of a Nairobi Fly includes ugly patches of blisters on affected areas, as well as severe itching.

The toxin is released when the beetle is crushed against the skin, which happens often when you try to brush it off.  

During the 2007 breakout, the then Health Ministry entomologist John Ouma and his team, advised against crushing the beetles and suggested that people instead blow them gently off their bodies. The Ministry of Health recommends that in case you inadvertently squeeze the insect on your skin, you should immediately wash the area of contact with soap and water to minimise the effects of the toxin.

Nairobi Fly, like many flies, is attracted to fluorescent lights. When the lights are turned off, the flies drop and start crawling and may find their way to the bed when you are asleep. The natural instinct would be to swat it, which would eventually lead to the release of the toxic haemolymph.

If the toxin comes into contact with the eyes, they become swollen, red and oozy, hence the name Nairobi Fly. Secondary infections can arise, especially if one incessantly scratches the resulting blisters.