Nairobi fly: Understanding its effects, habitat and treatment

The Nairobi fly, often referred to as the 'Kenya fly' or 'Acid fly,' is an insect native to East Africa, particularly prevalent in Kenya.

Belonging to the Paederus genus, these small beetles are known for their striking orange and black colouration.

Despite their innocuous appearance, they can cause significant skin irritation and lesions through accidental contact.

Effects of the Nairobi Fly

The primary issue with Nairobi flies arises when they are crushed against the skin. Unlike many other insects, Nairobi flies do not bite or sting.

Instead, their bodily fluids contain a potent chemical called pederin, which is responsible for the skin reactions.

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Dermatitis linearis

The most common condition resulting from contact with Nairobi fly is a form of dermatitis known as dermatitis linearis.

It manifests as a linear streak of redness and blistering on the skin, often accompanied by a burning sensation and itching.

Severe reactions

In some cases, exposure to pederin can lead to more severe reactions, including large blisters, secondary infections, and extensive skin damage.

The affected area can take weeks to heal, leaving behind dark pigmentation that may last even longer.

Eye irritation

If pederin gets into the eyes, it can cause severe conjunctivitis, characterized by redness, swelling, and a significant amount of pain.

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Causes and habitat

Nairobi flies thrive in warm, humid environments. They are commonly found in agricultural regions, attracted by light and moisture. The proliferation of these flies is often linked to:

1. Heavy rainfall: Increased rainfall creates a conducive environment for their breeding.
2. Bright lights: They are nocturnal and are attracted to artificial lights, which brings them into closer contact with human habitats.
3. Agricultural practices: Regions with extensive farming provide ample food sources and breeding grounds for these insects.

Prevention

Preventing encounters with Nairobi flies involves several practical measures:

1. Reducing exposure to light: Minimising the use of bright lights at night can reduce their attraction to homes.
2. Using insect screens: Installing screens on windows and doors helps keep them out of living spaces.
3. Maintaining cleanliness: Keeping the surroundings clean and free of organic waste reduces breeding sites.
4. Wearing protective clothing: When in areas prone to Nairobi fly infestations, wearing long-sleeved shirts and pants can help protect the skin.

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Treatment after contact

If contact with a Nairobi fly occurs, it is crucial to follow these steps to minimise the effects:

1. Avoid crushing the Insect: If a Nairobi fly lands on your skin, gently blow it away instead of crushing it.
2. Immediate washing: Wash the affected area with soap and water as soon as possible to remove any pederin residue.
3. Applying cold compresses: To alleviate pain and reduce inflammation, apply cold compresses to the affected area.
4. Topical treatments: Use antiseptic creams and calamine lotion to soothe the skin. In cases of severe reaction, topical steroids may be prescribed by a healthcare professional.
5. Oral antihistamines: These can help reduce itching and allergic reactions.
6. Seeking medical advice: If symptoms are severe or there are signs of infection, it is important to seek medical attention promptly.