Leishmania in Geckos on Mallorca: What We Know Now — and What Should Be Done

Leishmania in Geckos on Mallorca: What We Know Now — and What Should Be Done

When I recently stood against a house wall in Palma late in the evening, I heard the soft rustle of the palm trees and saw a small gecko darting nimbly across the plaster. Pleasant to watch, useful against mosquitoes — and now also scientifically interesting: a recent study has detected various Leishmania species in wild geckos on Mallorca.

The numbers at a glance

The study examined 59 individuals, mostly Tarentola mauritanica (Mediterranean wall gecko). The result is clear: 26.5 % of the adult animals carried Leishmania tarentolae, 8.2 % were infected with Leishmania infantum, and 6.1 % had both species simultaneously. No positive samples were found in the Turkish gecko (Hemidactylus turcicus). This is the first documented detection of such parasites in reptiles in Spain — a finding that is drawing attention from experts on Mallorca.

The key question: Are geckos a risk factor?

The central question is not "Do geckos have Leishmania?" but: Do they influence the transmission network in a way that makes dogs or humans more at risk? In the Balearics, canine leishmaniasis is already endemic. The pathogens are transmitted by phlebotomine sand flies; since the 1980s these insects have become more common in parts of southern Europe, favored by milder winters.

What researchers and veterinarians are discussing

It is important to distinguish between detecting pathogens in a reptile and the role as an infectious reservoir host. A gecko can carry Leishmania genetic material — but whether it carries enough parasites to infect sand flies is still open. Some previously little-considered aspects should be given more weight: the interactions between different hosts (dogs, small mammals, reptiles), the local density of sand flies in urban districts like the Paseo Marítimo or in more rural areas, and seasonal fluctuations when evenings become warmer and more humid.

Concrete risks — and what we don't know

For most people the risk remains low. Humans do fall ill in rare cases, but dog owners have particular reason for concern: dogs are the best-known reservoir for Leishmania infantum and can become ill themselves (see WHO fact sheet on leishmaniasis). Uncertain factors include vector preference (do sand flies prefer reptile or mammal blood?) and how long and in which body regions the parasites persist in geckos.

Practical recommendations for Mallorca

No panic, but stay alert: simple, proven measures are advisable for dog owners and anyone who spends a lot of time outdoors. These include regular veterinary check-ups, effective insect protection for dogs (repellents, medicated collars), evening caution during walks, enclosed sleeping places and insect screens on windows. In daily life you encounter geckos everywhere — on restaurant walls, in gardens, on old stone facades — so it is best to admire them from a distance and avoid unnecessary handling.

What authorities and researchers should do now

The study suggests that surveillance should be expanded: systematic sand fly trapping, closer cooperation between veterinarians and public health offices, as occurred after the First West Nile Case in the Balearic Islands: What the Horse Discovery on Menorca Means, and targeted follow-up studies of reptile populations in different habitats (urban vs. rural, coastal vs. inland). It would also be useful to run studies that test whether sand flies actually become infectious after blood meals from geckos — so-called vector competence tests.

A realistic outlook

The microclimate on Mallorca is changing: warmer summers, milder winters, more tourists, more pets. All of this creates new dynamics, without warranting an immediate alarm. Practical precautions and better data are the keys. While researchers analyze samples and plan further field studies, simple protective measures help keep infection risk for dogs and people low, and these dynamics are similar to other challenges such as Bluetongue Serotype 3 in Mallorca: How the Island Can Prevent Spread in the Mountains.

In the end there remains a bit of local everyday magic: the geckos do what they always do — hunt flies in the evening, make no noise, are useful and are now also a small research detail in Mallorca's large ecosystems. Anyone truly engaged in observing nature knows: often it is the inconspicuous things on a house wall that pose the most complicated questions.