An underestimated, potentially serious infectious disease

Do you know people who work with animals, or in humid environments?
They may be at risk of contracting leptospirosis.

Weil’s disease

Leptospirosis, commonly called “Weil’s disease”, is a misunderstood bacterial disease transmitted to humans by some mammals.

The bacteria, called “Leptospira”, are primarily stored in the kidneys of contaminated animals, before passing into their urine. The animal’s coat and surrounding environment then become contaminated.

Rodents and rats, in particular, are carriers of the most severe, sometimes fatal, form: Icterohemorrhagic leptospirosis(1).
The most serious is L. Icterohaemorrhagiae serogroup recognized as the most widespread in Western Europe(2).

In metropolitan France, for example, icterohemorrhagic leptospirosis accounts for a third of identified cases and, in particular, two thirds of serious cases requiring hospitalization(3).

More and more people are contracting leptospirosis worldwide each year. Overall, leptospirosis was estimated to cause more than 1 million cases and 58,900 deaths each year(4).

In the United Kingdom, icterohemorrhagic leptospirosis accounts for approximately half of identified cases(5), and two thirds of identified cases in the Netherlands(6). Elsewhere in the world, Icterohaemorrhagiae accounts for two thirds of the cases in Réunion, for example, and half of the cases in French Polynesia(7,8).




Cases of leptospirosis identified in metropolitan France

Leptospirosis: not just a tropical infection

Icterohemorrhagic leptospirosis is the predominant form of the disease in several countries worldwide, including France, its overseas departments (except Mayotte)(1), the United Kingdom(5), and the Netherlands(6).

This infection is endemic in tropical and subtropical regions, but can also be found in regions with more temperate climates.

2014: 628 cases of leptospirosis in metropolitan france, the highest incidence in 80 years.

In metropolitan France, the number of cases has doubled in recent years, rising from 300 to more than 600 identified cases annually, i.e more than one case a day since 2014(9).

Leptospirosis is re-emerging in Europe and across the globe(10). It is an overlooked, and very probably underestimated, disease(1).

In the United Kingdom, for example, 2017 saw the highest incidence for 10 years(11,12).

According to experts, leptospirosis is an emerging public health issue. Climate change and urbanization promote the spread of this disease, particularly through the proliferation of rats and coypu in our cities and countryside(1).

Laboratory confirmed cases of leptospirosis in humans in the United Kingdom
Laboratory confirmed cases of leptospirosis in humans in the United Kingdom

Did you know that leptospirosis is recognized as
an occupational disease throughout the world?

Rights of workers exposed to leptospirosis

The potentially serious consequences of leptospirosis on the health of workers has led the International Labor Organization to recognize it as an occupational disease, to ensure that victims are compensated(13).

This recognition is also applicable under European and French law(14). Furthermore, the protection of workers is guaranteed under French law. For example, employers are obliged to protect the moral and physical health of their employees and agents, with the assistance of Occupational Physicians and Multidisciplinary Occupational Health Teams(15,16).

leptospirosis, an occupational disease

Leptospirosis affects several professions

In France, leptospirosis is sometimes commonly known as “sewage worker’s disease” (maladie des égoutiers).

These workers are directly exposed to rats and water contaminated with their urine. However, this is not the only job that carries a risk of leptospirosis infection.

In France, for example, tables of occupational diseases suggest a list of at-risk activities that fall under the following definition: “work that exposes staff to contact with animals likely to be carrying bacteria, particularly when performed in contact with water or in humid places likely to be contaminated with the excrement of such animals.”

In France, leptospirosis is work-related in a third of all identified cases. Among working-age individuals, 54% of cases are contracted at work(17,18).

In the United Kingdom, the Health and Safety Executive (HSE), which has responsibility over occupational health and safety, lists some professions carrying the risk of leptospirosis (Weil’s disease): watersports instructors; workers in outdoor leisure industries, particularly if in contact with water; sewage and waste water workers; construction/demolition/building renovation workers – where there are rodents or stagnant water; farm workers; and pest control workers(19).

Did you know that certain leisure activities expose
the population to the risk of leptospirosis?

Outdoor activities and sports at risk of leptospirosis

With the development of urbanization, leisure activities are more oriented towards outdoor activities that can expose people to the risk of contracting leptospirosis, by facilitating contact between humans and infected animals or environments.

Activities that occur in fresh water like swimming, triathlon, diving, canoeing, rafting and windsurfing are becoming increasingly popular and are among the main causes of contamination during leisure activities.

Other outdoor activities and sports practiced in a wet or muddy environment also represent a risk factor: speleology, canyoning, nature trails (raids), mud trails (MudDay), but also gardening.

Finally, activities involving direct contact with infected animals or environments, such as hunting, trapping or fishing, also present a risk of contamination.

leptospirosis contamination diagram

Rodents and fresh water: the primary risk factors

Once dispersed through the urine of contaminated animals, such as rats or livestock, the bacteria which cause leptospirosis can survive for up to six months in fresh water or a humid location(20, 21).

If you know someone who is at risk of contracting leptospirosis due to the nature of their work (sanitation, public works, etc.) or leisure activities (canyoning, triathlon, fishing, hunting, etc.), it’s essential that they take measures to protect themselves, as Leptospira are thin, mobile bacteria that can penetrate the body through various means(22).

These bacteria can penetrate through:
– wounds or scratches
– eyes, nose, mouth
– the dilated pores of healthy macerated skin(22)

A potentially serious illness

The first symptoms of leptospirosis may present rapidly after contact with the bacteria, or sometimes over a longer timeframe – which can make diagnosis slow and difficult(22).

After the incubation phase, leptospirosis first resembles the flu.

If initiated early, antibiotic treatment can suffice to treat leptospirosis, but in some cases the infection can continue to worsen.

In the most serious cases, the Leptospira can damage organs such as the kidneys, liver, and lungs, and admission to an intensive care unit is thus often necessary. Leptospirosis can still sometimes be fatal, even when intensive care measures have been taken(22).

When dealing with leptospirosis,
prevention is better than a cure.

As leptospirosis is a misunderstood illness, awareness among those who perform at-risk activities is a necessity.

In case of regular exposure

You should use and recommend appropriate methods of prevention.
Healthcare professionals can answer questions and advise on actions and appropriate means of protection for professional or leisure activities (wearing boots, goggles, etc.)(23,24).

Healthcare professionals can also assess whether vaccination is necessary, in addition to the other methods of prevention, based on the official recommendations.

Disinfect and protect

wounds or scratches with waterproof dressing

leptospirosis prevention

Wash your hands

with soap and clean water after sport or leisure activities

leptospirosis prevention

Avoid any contact

with your eyes, nose and mouth with dirty hands

leptospirosis prevention-3

Wear protective equipment

depending on the activity (boots, overalls, protective goggles)

leptospirosis prevention-4

Consult your general practitioner

if you experience influenza-like symptoms and inform those exposed

leptospirosis doctor

Get vaccinated

if advised to do so by a healthcare professional, based on official recommendations.

leptospirosis vaccine

For frequently-exposed workers

The bacteria that causes leptospirosis is a Group 2 biological agent, i.e. one which “Can cause human disease and may be a hazard to employees; it is unlikely to spread to the community and there is usually effective prophylaxis or treatment available” (25).

In France, specific monitoring of group 2 biological agents – such as leptospirosis – should be performed jointly by the between the employer and the Department of Occupational Health(16). This monitoring allows an effective and appropriate prevention plan to be put in place.


The Health and Safety Executive (HSE) in the United Kingdom has developed an “Are you at risk?” information sheet for at-risk workers(26).

It is also important to limit the proliferation of rodents and rats, particularly through good waste management practices.

Do you want to implement awareness and prevention measures?


As a specialist in the prevention of human leptospirosis, Imaxio engages with companies, health authorities and occupational healthcare professionals in their awareness and prevention activities.

For this purpose, Imaxio provides you with various information and awareness materials on leptospirosis.

If you wish to go further and set up an information meeting, an information and prevention officer can intervene in your establishment.

leptospirose Facebook
Discover our page dedicated to leptospirosis.
Access our Facebook page

(1) Filleul L. et al. ; Santé Publique France – La leptospirose dans les régions et départements français d’outre-mer; Bulletin Epidémiologique Hebdomadaire; 4 avril 2017 ; numéro 8-9
(2) Taylor AJ, Paris DH, Newton PN (2015) A Systematic Review of the Mortality from Untreated Leptospirosis. PLoS Negl Trop Dis 9(6): e0003866.doi:10.1371/journal.pntd.0003866
(3) Estavoyer JM. , « Leptospirose en Franche-Comté : données cliniques, biologiques et thérapeutiques. Médecine et maladies infectieuses »; Septembre 2013: pages 379-385
(4) Costa F, et al. (2015) Global Morbidity and Mortality of Leptospirosis: A Systematic Review. PLoS Negl Trop Dis 9(9): e0003898. doi:10.1371/journal.pntd.0003898
(5) A.E. FORBES, W.J. ZOCHOWSKI, S.W. DUBREY and V. SIVAPRAKASAM. Leptospirosis and Weil’s disease in the UK. QJM. 2012 ; 105 : 1151-1162
(6) Goris, M.G.A. (2016, April 6). Leptospirosis: epidemiology, clinical aspects and diagnosis. Erasmus University Rotterdam. Retrieved from
(7) Rapport d’activité 2013 pour l’année 2012 du Centre National de Référence de la Leptospirose – Inst. Pasteur Paris
(8) Berry AL et al. Bilan de la surveillance de la leptospirose en Polynésie Française 2006-2012 Bull. Info. Sanit. Epidémio. Stat. Dir. de la santé de Polynésie Fr. 2013; 9: 4-6.
(9) Picardeau M., Rapport annuel d’activité du CNRL 2018 pour l’année d’exercice 2017.
(10) Dupouey J et al. Human leptospirosis : an emerging risk in Europe? Comparative Immunology, Microbiology and Infectious Diseases 37 (2014) 77– 83
(11) Public Health England. Zoonoses Overview Report UK 2016. HM Government ; 2017. 50.
(12) Public Health England. Common animal associated infections quarterly report (England and Wales) : fourth quarter 2017. Health Protection Report. Volume 12 Number 5. 9 february 2018. 7.
(13) International Labour Office, List of occupational diseases (revised 2010). Geneva 2010 ; N°74 : 0-72.
(14) Directive Européenne 2000/54/CE (JOCE L. 262 du 17/10/2000)
(15) Soc. 30.11.2010 n°08-70.39
(16) Article L4622-2 du Code du Travail modifié par la loi n°2015-994 du 17 août 2015 – art. 16
(17) Baranton G, Postic D Centre National de Référence des leptospires, Institut Pasteur Paris, Synthèse La leptospirose en France de 2001 à 2003 : 1-8
(18) Watrin M. Étude descriptive des cas de leptospirose diagnostiqués en Normandie sur la période 2010-2014. Saint-Maurice : Institut de veille sanitaire ; 2016: 1-28.
(19) Health and Safety Executive. Leptospirosis (Weil‘s disease and Hardjo). 3.
(20) Ferguson IR. A european Perspective on Leptospirosis. Microbiology Europe 1994; janv-fév: 8-11
(21) Andre-Fontaine G et al. Waterborne Leptospirosis: Survival and Preservation of the Virulence of Pathogenic Leptospira spp. In Fresh Water. Curr Microbiol. 2015 Jul;71(1):136-42
(22) Adler B. (Ed) Leptospira and Leptospirosis, Current Topics in Microbiology and Immunology Sringer-Verlag Berlin Heidelberg 2015; 387: 1-293. DOI 10.1007/978-3-662-45059-8.
(23) Avis du Conseil Supérieur d’Hygiène Publique en France relatif aux recommandations pour la prévention de la leptospirose dans la population générale (séance du 30 septembre 2005)
(24) Avis du Conseil Supérieur d’Hygiène Publique en France relatif aux recommandations pour la prévention de la leptospirose en cas d’activité professionnelle à risque (séance du 18 mars 2005)
(25) Health and Safety Executive. The Approved List of Biological Agent. Advisory Committee on Dangerous Pathogens; Third Edition 2013. 35.
(26) Health and Safety Executive. Leptospirosis Are you at Risk ? 2011.2.

Last Updated : 27 january 2020