Leishmaniasis and sandflies in southern Europe

A parasite carried by a very small insect

Leishmaniasis is a parasitic disease caused by infection with Leishmania parasites, which are spread by the bite of infected sandflies. The US Centers for Disease Control and Prevention classifies it as a neglected tropical disease. The insects involved are phlebotomine sandflies. They are silent, very small, and only about one fourth the size of mosquitoes, so many people never notice the bite itself. The European Centre for Disease Prevention and Control states that phlebotomine sandflies are the natural vectors of Leishmania parasites in Mediterranean countries. That matters for residents and visitors across southern Europe. A bite can pass on a parasite without any warning sting or buzzing sound. Knowing the insect and its habits is the first step to reducing exposure.

Three main forms of the disease

The World Health Organization describes three main forms of leishmaniasis: visceral, cutaneous, and mucocutaneous. Cutaneous leishmaniasis is the most common form. It causes skin sores, which usually develop within a few weeks or months of the sandfly bite and are often painless according to the CDC. Visceral leishmaniasis affects internal organs, especially the spleen, liver and bone marrow. The European Centre for Disease Prevention and Control notes that it can invade these organs and can be fatal if left untreated. The World Health Organization puts the untreated fatality figure for visceral disease at over 95 per cent of cases. These are broad clinical categories, not a prediction for any one person. A doctor assesses symptoms and travel history before reaching any diagnosis.

Why southern Europe matters

In the WHO European Region, cutaneous and visceral leishmaniasis are endemic, and imported cases are common, coming mainly from Africa and the Americas. Within Europe, the picture is local. European Centre for Disease Prevention and Control experts report that Leishmania infantum is widespread in Mediterranean countries, while Leishmania major and Leishmania tropica are restricted to North Africa, the Middle East and Asia Minor. The same source notes that sandflies in Europe are gradually expanding northwards. It also warns that movement of dogs infected with L. infantum will probably establish new infection foci in more northerly areas where the vector is present. This is a slow geographic shift, not a sudden emergency, but it means risk maps are not fixed forever.

The insects prefer quiet, low bites

Sandflies are active between dusk and dawn, which is when people are most likely to be bitten, according to the CDC. Their small size lets them pass through some ordinary mesh, so a screen that stops mosquitoes may not stop them. European Centre for Disease Prevention and Control experts describe how, in southern Europe, the vectors of L. infantum have adapted to peri-urban residential areas containing detached houses with gardens and dogs. That describes many ordinary neighbourhoods rather than remote wilderness. Gardens, animal shelters, stone walls, and shaded resting spots can all support local populations. The practical message is that risk can exist close to home, including in a well-kept garden. Simple attention to where the insects rest and feed is more useful than alarm.

Dogs and other animals in the chain

Dogs can carry Leishmania infantum and can act as reservoir hosts. The European Centre for Disease Prevention and Control notes that, for dogs, collars impregnated with deltamethrin are used to control infection of reservoir dogs. Veterinary advice matters here, because animal health measures form part of the wider picture. The agency also links the movement of infected dogs to the possible creation of new infection foci where the vector is present. That is a public health observation about animal movement, not a reason to blame pet owners. For readers with dogs in southern Europe, a conversation with a vet about local risk and protection is sensible. Human protection and animal protection are separate but connected tasks, and both belong in a calm, consistent routine.

Protection without promises

There is no available vaccination for leishmaniasis, and the CDC confirms there are no vaccines or drugs to prevent it. Even people who have had it before can get it again. The European Centre for Disease Prevention and Control lists protective measures: mosquito nets treated with insect repellent, applying insect repellent to the skin, and managing insects around the home. The World Health Organization points out that the parasite has developed resistance to some medications over time, which makes prevention more valuable than ever. Treat these measures as real protection when correctly specified, intact, and correctly used. A treated net only helps if it is in good condition and used consistently. Repellents only help when applied as directed. No single step removes all risk.

What a reader can do next

For health-literate readers planning time in southern Europe, the useful habits are unglamorous and steady. Cover exposed skin during dusk to dawn hours and use repellent on skin as directed. Check window and door screens, and use a treated net where sleeping areas are not fully protected. Keep animal resting areas clean and seek veterinary advice for dogs. If a persistent skin sore appears after time in an endemic area, or if fever and weight loss occur, mention the travel history to a clinician. The World Health Organization reports an estimated 50,000 to 90,000 new visceral cases worldwide each year, with only 25 to 45 per cent reported. Reporting gaps mean official counts are a guide, not a full picture.

Sources

• Leishmaniasis: European Centre for Disease Prevention and Control
• Leishmaniasis: World Health Organization
• About Leishmaniasis | Leishmaniasis | CDC: US Centers for Disease Control and Prevention
• Phlebotomine sand flies - Factsheet for experts: European Centre for Disease Prevention and Control