Leptospira is a spiral bacterium that causes leptospirosis.

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In August 2023, Wyoming reported its first human case of leptospirosis since 1983, likely due to a spillover event, the transmission of infection from animal to human. This unusual event prompted an investigation in a low-risk area and highlighted the importance of increased canine vaccinations. Following the outbreak, veterinary clinics significantly raised their recommendations for the leptospirosis vaccine, resulting in higher compliance among pet owners.

Courtney Tillman, MPH, an epidemiologist from Wyoming, discusses the need for routine dog vaccinations. She emphasizes the importance of awareness regarding occupational risks to prevent leptospirosis transmission to humans. Tillman advocates for a One Health approach and effective community engagement by public health officials.

In response to the outbreak, public health authorities took immediate action to investigate and mitigate the risks, “Public health worked with the state veterinarian to educate veterinarians in this city about the current outbreak, symptoms in animals, risks, and recommendations for vaccination of dogs. Public health informed healthcare providers in this area about the outbreak and what to be on the lookout for in terms of symptoms that can be present when humans are infected. Additionally, a press release was issued to inform the public about the outbreak and provide recommendations for prevention,” according to Tillman.

Understanding Leptospirosis

Leptospirosis is a disease caused by the Leptospira bacterium, found in contaminated water or soil, affecting both animals and humans. If untreated, it can lead to serious complications in people, including kidney damage, meningitis, liver failure, respiratory issues, and death. Approximately 1 million human cases and nearly 60,000 deaths occur worldwide each year, with reports throughout the United States. Animals can also become infected through contact with contaminated fluids, and symptoms can vary significantly, with some animals remaining asymptomatic.²

“It is important to keep animals up to date on recommended vaccinations to help prevent infection in animals that can be transmitted to humans. Healthcare providers evaluating patients for potentially infectious diseases should inquire about occupation and exposures to potential sources of infectious diseases, such as animals. Early detection and treatment of leptospirosis can help prevent severe illness,” explains Tillman “One Health (human, animal, and environmental) approach is imperative when responding to zoonotic disease events. In this outbreak, an early alert by a local veterinarian of an increase in canine leptospirosis cases facilitated rapid intervention by public health authorities.”

One Health is a collaborative, multisectoral, and transdisciplinary approach — working at the local, regional, national, and global levels — to achieve optimal health outcomes by recognizing the interconnection between people, animals, plants, and their shared environment.²

Tillmans’s advocacy for a One Health approach acknowledges the interconnectedness of human health, animal health, and our shared environment. While not a new concept, its significance has grown in recent years due to various factors altering the interactions among people, animals, plants, and the environment.²

This outbreak highlights the need for enhanced preventive measures. It also shows the importance of public health education for individuals with occupational exposure to animals. Actions include promoting vaccinations, improving surveillance for zoonotic diseases, and ensuring timely outbreak reporting. Clinicians should consider leptospirosis in individuals with relevant exposure and symptoms, regardless of geographic risk factors.

References

1. Waranius B, Tillman C, Van Houten C, et al. Human Case of Leptospirosis During a Canine Disease Outbreak — Wyoming, 2023. MMWR Morb Mortal Wkly Rep 2024;73:602–606. Published July 11, 2024. Accessed July 16, 2024. DOI: http://dx.doi.org/10.15585/mmwr.mm7327a1

2. CDC. About Leptospirosis. Published June 24, 2024. Accessed July 16, 2024. https://www.cdc.gov/leptospirosis/about/index.html

3. CDC. One Health. Published June 25, 2024. Accessed July 16, 2024. https://www.cdc.gov/one-health/about/index.html