Leishmaniasis: How to Prevent the Sandfly Bite and What to Do if You Are Infected

What Is Leishmaniasis and How Does It Spread?

Leishmaniasis is caused by microscopic parasites of the genus Leishmania, transmitted to humans through the bite of an infected female sandfly of the genus Phlebotomus in the Middle East and North Africa. The sandfly is tiny, no bigger than three millimetres, flies almost silently and its bite is often not felt at all. This makes the exposure difficult to remember when symptoms appear weeks or months later.

The sandfly is active from dusk through to dawn. It breeds in dry, warm environments such as cracked walls, animal shelters, rubble piles and stony soil. It does not fly long distances, which means the exposure usually happens close to where you live or work, not from some distant source.

The parasite lives in the blood of animal reservoirs such as rodents and dogs. The sandfly feeds on an infected animal, ingests the parasite, which then multiplies inside it, and injects it into the next person it bites. A 2022 study in Frontiers in Microbiology documented increasing leishmaniasis burden across the Middle East, noting that conflict-related displacement was pushing populations into endemic areas without prior immunity, creating new transmission cycles. The disease does not spread from person to person through any form of direct contact.

Skin Form versus Visceral Form: A Crucial Distinction

Leishmaniasis is not a single disease but a spectrum of clinical forms that differ greatly in severity. The most common form across the Arab world is cutaneous leishmaniasis, known popularly as Aleppo boil, Baghdad boil or oriental sore. It causes a skin ulcer at the site of the sandfly bite, most often on the face, arms or legs.

The ulcer begins as a small raised lump, then opens and ulcerates with characteristic raised edges, persisting for months and sometimes longer than a year before healing on its own. It almost always leaves a permanent scar. This form is rarely life-threatening, but a prominent facial ulcer can cause significant psychological and social distress, particularly for children and young women, which makes treatment worthwhile even when it is not medically urgent.

Visceral leishmaniasis, known as kala-azar, is the most dangerous form by a very wide margin. The parasite invades the bloodstream and infects the spleen, liver and bone marrow. Without treatment, the fatality rate approaches 100 percent. This form is most common in Sudan, Yemen, and parts of East Africa, though pockets exist elsewhere in the region.

Symptoms of the Skin Form: What to Look For

Cutaneous leishmaniasis appears weeks to months after the sandfly bite, and this long delay means many people do not connect the ulcer with a bite they cannot remember. The lesion begins as a small red papule resembling a pimple, grows steadily, and eventually opens in the centre with the classic raised, indurated border. The surface may be crusted, moist or actively oozing.

The ulcer is usually painless or far less painful than its size suggests. Some ulcers dry and crust over without ever fully opening. Left untreated, many heal over six to twelve months but leave a permanent scar at the site. An ulcer on the face, especially near the nose or ear, needs treatment to prevent spread to the mucous membranes of the nose and mouth, which causes the more disfiguring mucocutaneous form.

The skin form does not usually cause fever or systemic symptoms unless the ulcer becomes secondarily infected with bacteria. If you notice increasing pain, spreading redness around the ulcer and fever, this suggests a bacterial superinfection requiring antibiotics alongside leishmaniasis treatment.

Symptoms of Visceral Disease: When Leishmaniasis Becomes Dangerous

Visceral leishmaniasis develops slowly over months and is frequently mistaken for other conditions during that time. The classic presentation includes intermittent fever coming and going in waves, progressive weight loss and wasting, and a massively enlarged spleen that can be felt well below the left rib margin. The liver also enlarges. Severe anaemia makes the patient increasingly pale, weak and breathless.

As the disease progresses, the immune system collapses, leaving the patient vulnerable to serious secondary infections including tuberculosis and bacterial pneumonia. The bone marrow becomes affected, dropping all blood cell lines. This is why a patient who looked merely tired and feverish three months ago may present in very poor condition by the time they reach hospital.

A 2012 review in the Infectious Disease Clinics of North America confirmed that visceral leishmaniasis is curable in over 90 percent of cases when diagnosed and treated with the right drugs early in the illness. The tragedy is that most deaths occur not from treatment failure but from patients reaching hospital too late.

How to Protect Yourself from Sandfly Bites

There is no licensed human vaccine against leishmaniasis despite decades of research. Personal protection is your only defence. The sandfly is small enough to pass through standard mosquito net mesh, so you need a fine-mesh net with openings no larger than 1.5 millimetres, or one treated with an insecticide such as permethrin, which kills the sandfly on contact even through the mesh.

Insect repellents containing at least 20 percent DEET applied to exposed skin and clothing provide reliable protection during the sandfly's active hours from dusk to dawn. Permethrin-treated clothing adds a further layer. Light-coloured, long-sleeved shirts and trousers tucked into socks limit exposed skin during evening hours when the risk is highest. These precautions are particularly important for anyone working or sleeping outdoors in rural areas.

The sandfly favours environments close to the ground: cracked walls, rubble, grain stores, livestock shelters and stony soil. Sealing cracks in home walls, keeping the area around the house clear of rubble and managing animal housing away from sleeping areas reduces your immediate exposure. Sleeping in an air-conditioned room with closed windows is protective because the sandfly does not fly far and struggles against air movement.

How Is Leishmaniasis Diagnosed?

For the skin form, diagnosis is made by taking a scraping or small biopsy from the edge of the ulcer and examining it under a microscope to identify the Leishmania parasite. The Montenegro skin test detects immune response to the parasite and is used in some settings. PCR testing is more sensitive but requires laboratory infrastructure that is not uniformly available across the region.

For the visceral form, the rK39 rapid diagnostic test detects antibodies in the blood and performs well in most endemic settings, giving a result within minutes. A full blood count showing anaemia with low white blood cells and low platelets together with an enlarged spleen on examination or ultrasound strongly suggests kala-azar. Bone marrow aspiration, which provides definitive diagnosis, is reserved for cases where the rapid test is inconclusive.

Early diagnosis is the strongest predictor of a good outcome. In Sudan and Yemen, studies have found that many visceral leishmaniasis cases arrive at health facilities only in advanced stages, partly because the early symptoms of prolonged fever and weight loss are attributed to malaria or other common infections.

Available Treatments and What to Expect

For the skin form, the treatment decision depends on the size and site of the ulcer, the number of lesions and the Leishmania species causing it. Small ulcers on the trunk or limbs may be observed without active treatment. Larger or facial ulcers are treated with intralesional injections of pentavalent antimony compounds directly into and around the ulcer, or with systemic treatment such as miltefosine tablets or intravenous amphotericin.

For visceral leishmaniasis, liposomal amphotericin B is now the preferred treatment in most settings and achieves cure rates above 90 percent when given appropriately. Pentavalent antimony compounds (meglumine antimoniate or sodium stibogluconate) remain in use where amphotericin is unavailable, though resistance is an increasing problem in some areas. Miltefosine, an oral drug, has also been used with good results in certain regions.

Completing the full treatment course is essential regardless of how quickly symptoms improve. Stopping early allows surviving parasites to re-establish, potentially in a drug-resistant form. All treatments for visceral leishmaniasis require medical supervision and some require hospital admission for administration and monitoring.

Leishmaniasis in the Context of Conflict and Displacement

Armed conflict dramatically increases leishmaniasis transmission through interconnected mechanisms. Displacement drives populations from cities into rural endemic areas without any acquired immunity. Destroyed infrastructure removes sanitation and creates rubble habitats that are ideal sandfly breeding grounds. Collapsed health systems make diagnosis and treatment inaccessible precisely where need is greatest.

Syria experienced large-scale outbreaks of cutaneous leishmaniasis in refugee camps and conflict-affected areas during years of war. Researchers have documented how disease surveillance systems collapse first in conflict zones, making individual prevention and prompt care-seeking more important precisely when institutional responses are weakest. If you are living in or passing through conflict-affected areas known for leishmaniasis, personal protection measures are non-negotiable.

People who are already immunocompromised, whether from HIV, medications after organ transplant, or drugs used for autoimmune conditions, face a sharply elevated risk of visceral disease and of reactivation of past latent infections. If you take immunosuppressant medication and you live in or plan to visit an endemic area, discuss this explicitly with your doctor before travel.

Reducing Sandfly Habitat Around Your Home

Beyond personal protection, modifying the immediate environment reduces the sandfly population around your home and lowers the overall exposure of your whole household. The sandfly does not travel far, typically less than a few hundred metres from its breeding site, so addressing the sources close to home has a meaningful impact.

Keep the ground around the house clear of organic debris, rubble piles and discarded materials that create shaded, moist micro-habitats close to the soil. Animal shelters such as dog kennels and livestock pens are particularly important sites because animals are both a blood meal source for the sandfly and a reservoir host for the Leishmania parasite. Positioning animal housing away from sleeping areas reduces night-time sandfly pressure on your family. Treating dogs with insecticide-impregnated collars (permethrin-based) is used in some programmes as an additional measure to reduce transmission.

In areas of high endemicity, community-level spraying of residual insecticides on the walls and floors of houses reduces sandfly numbers. If your community health programme offers this service, it complements but does not replace personal protection. Window screens with fine mesh provide a passive barrier when doors and windows need to be open during hot nights. Combining environmental measures with nets and repellents gives the most complete protection available in the absence of a vaccine.

Sources

• Knight CA, Harris DR, Alshammari SO et al: Leishmaniasis: Recent epidemiological studies in the Middle East, Frontiers in microbiology, 2022
• Jacobson RL: Leishmaniasis in an era of conflict in the Middle East, Vector borne and zoonotic diseases (Larchmont, N.Y.), 2011
• van Griensven J, Diro E: Visceral leishmaniasis, Infectious disease clinics of North America, 2012
• Kumosani TA, Al-Bogami TJ, Barbour EK et al: Leishmaniasis prevalence, awareness and control in Saudi Arabia, African health sciences, 2022
• Daga MK, Rohatgi I, Mishra R et al: Leishmaniasis, Indian journal of critical care medicine, 2021
• World Health Organization: Leishmaniasis fact sheet