Leptospirosis in Réunion: 71 cases in March 2026, a historic peak that highlights the central role of rats

Leptospirosis is hitting an unprecedented level in Réunion in early 2026. According to the epidemiological surveillance bulletin of Santé publique France and the ARS Réunion published on 17 July 2026, 217 autochthonous cases were reported between 1 January and 16 July 2026, with a historic peak of 71 cases in March — a level never reached since monitoring began. For pest-control professionals and for the general public, this record is a sharp reminder of an often-overlooked fact: rats remain the main reservoir of the disease, and rodent control is one of the first lines of public-health defence.

What the official bulletin of 17 July 2026 says

The regional epidemiological report, written by Santé publique France Réunion and the ARS Réunion, documents the 2026 season in detail. The monthly distribution of the 217 cases is unambiguous:

With 71 cases in March 2026, Réunion exceeded for the first time the historical monthly maximum of 61 cases observed in March 2024. The peak is linked to the classic combination on the island of heavy cyclonic or late-austral-summer rainfall (washing contaminated soil into waterways), stagnant fresh water (ravines, irrigation canals) and a dense commensal rodent population, particularly in the sugarcane agricultural zones and the working-class neighbourhoods of Saint-Denis, Saint-Pierre, Le Tampon and Saint-Paul.

120 patients were hospitalised, i.e. 65 % of cases, and one death was classified as directly attributable to leptospirosis by the death-imputability committee. A second death is also currently under investigation.

Source: Surveillance sanitaire à La Réunion, Week 28 (06–12 July 2026), Santé publique France / ARS Réunion, 17 July 2026, p. 5.

Why Réunion is a particularly exposed area

Réunion combines several factors that make it a reference territory for leptospirosis in France. The bacterium Leptospira interrogans, excreted in the urine of rats (mainly the brown rat Rattus norvegicus and the black rat Rattus rattus), survives for several weeks in warm fresh water, and the island offers an ideal terrain for this chain of transmission:

• Warm and humid tropical climate, with abundant rainfall (record in March 2026 at several Météo-France stations in the east and south);
• High rodent density in the lowlands, near waterways, sugarcane fields, landfills and informal housing areas;
• Multiple risk exposures: gardening, farming, swimming in rivers or ponds, freshwater fishing, canyoning — all activities widely practised on the island;
• Freshwater leisure activities particularly implicated: the 2026 bulletin highlights that 40 cases are linked to swimming, fishing or canyoning, compared to only 12 in 2025.

The ARS Réunion reminds that the diagnosis should be considered in front of any dengue-like syndrome occurring in a context of risk exposure: sudden high fever, chills, diffuse muscle pain, headaches, jaundice (yellowing of the skin and eyes) in severe forms. A chikungunya/dengue/leptospirosis triplex PCR is available in all laboratories on the island to confirm the diagnosis quickly.

The rat, the first link in the chain

Leptospirosis is not a disease "of dust" or "of mud" in the general sense: it is a zoonosis of which the rat is the main reservoir. The animal is a healthy carrier (it is not sick), continuously excretes the bacterium in its urine, and contaminates:

• fresh water (ravines, canals, ponds, fountains, drinking troughs);
• muddy soils in gardens, farms, construction sites;
• stored foodstuffs (cereals, fallen fruit, feed bags).

Humans are most often contaminated by contact with this water or mud, the bacterium entering through the mucous membranes (eyes, mouth, nose) or through a wound, however minor. A simple graze on the calf after a walk in a ravine is enough. This is why the fight against rats is not only a question of comfort or image: it is a public-health issue that the March 2026 Réunion peak confirms once again.

What leptospirosis says about the sanitary state of a territory

Each autochthonous case is a signal. At the scale of a neighbourhood, a commune or a farm, the occurrence of one or more cases should trigger a rapid assessment:

1. Identify contaminated water points: ravines, irrigation canals, drains, manholes, septic tanks, post-rain stagnation points;
2. Assess the rodent population: presence of burrows, fresh droppings (5 to 10 mm, black, capsule-shaped), scratch marks, damage to cables, plastics, foodstuffs;
3. Look for sources of food and shelter: accessible waste deposits, open composts, wood piles, dense vegetation close to dwellings, unprotected animal feeders;
4. Trigger a rodent-control plan targeting the risk zones, with the intervention of a certified company capable of setting up a safe system (secure bait stations, anticoagulant rodenticides, weekly follow-up).

Acting on both fronts: rats and exposure

The 2026 ARS Réunion bulletin insists on combined prevention: acting on both the reservoir (rats) and the exposure (human activities). For individuals as for professionals, this means following a simple checklist:

• Wear closed shoes, boots and gloves during any activity in a humid environment (gardening, cleaning a cellar, emptying pits, livestock);
• Disinfect and systematically protect any wound before exposure (waterproof dressing, double gloves);
• Avoid swimming in fresh water in the days following heavy rainfall, and a fortiori with open wounds;
• Fight rats around the home and farm buildings: remove food sources, block access holes (≥ 1 cm), install secure bait stations along cable runs and at the foot of facades, call a professional as soon as their presence is confirmed;
• Consult a doctor quickly in case of fever within 2 to 30 days following a risk exposure: leptospirosis is treated effectively with antibiotics (cycline, penicillin, or ceftriaxone in severe forms) provided it is managed early.

A signal to read beyond Réunion

If Réunion is a reference territory for leptospirosis, the bacterium also circulates, at a lower level, in mainland France: 600 to 700 cases per year are recorded there according to Santé publique France, with a summer peak linked to river bathing and canyoning. Grand Est, Bourgogne-Franche-Comté and Auvergne-Rhône-Alpes are the most affected regions. City rats (Paris, Lyon, Marseille) and coypus in metropolitan wetlands maintain the same transmission cycle.

The March 2026 Réunion episode should serve as a reminder: where rats proliferate, leptospirosis follows. The regulation of rodent populations — through prevention (sealing, hygiene, waste management) and through professional rodent control — is, together with individual protection, one of the two pillars of the fight against this sometimes fatal disease.

Need a diagnosis or an intervention in Réunion or in mainland France?

If you notice the presence of rats around your home, farm or business premises, don't settle for a single spray or a trap placed in the kitchen: rats breed quickly, adapt to conventional baits and transmit many diseases. A certified professional assesses the level of infestation, identifies entry points and sets up a safe and sustainable rodent-control plan.

Antinuisible Pro operates in Réunion and throughout mainland France, with a free diagnosis, a quote within 24 hours and discreet interventions. For an urgent situation (massive presence, visible contamination, food premises), contact us as a priority via our emergency page or request a diagnostic appointment with a technician near you. You can also consult our intervention zones and our indicative pricing to prepare your approach.

To go further, also read our article on rats spreading through cities (/en/blog/2024/03/18/rats-spreading-through-cities-understand-and-react) and our complete guide on rodent control in apartment buildings (/en/blog/2026/07/09/rodent-control-apartment-building).