Protect pets from two common bacterial diseases during Singapore’s wet weather season

SINGAPORE – As the rainy season approaches, pet owners should be aware of two diseases that may be associated with heavy rainfall. Understanding leptospirosis and melioidosis, and implementing preventive measures can help protect your dogs and cats from serious health risks.

Leptospirosis

Leptospirosis is a bacterial disease caused by the bacterium Leptospira spp. that is present worldwide and affects animals and humans.

The bacteria is transmitted through water contaminated with infected animal urine, particularly from rodents. During heavy rainfall, contaminated puddles and standing water create increased exposure risks for pets.

Dogs are particularly at risk and can be infected when they play in puddles and stagnant water. The bacteria enters through small cuts on paws and mucous membranes, or when pets drink contaminated water.

Cats can also become infected and, while they rarely show symptoms, may shed bacteria in their urine for extended periods. 

Pet owners should monitor for these symptoms in their dogs, particularly if they go outdoors:

Without prompt veterinary treatment, the infection can rapidly progress to kidney failure and prove fatal. 

Leptospirosis can also affect humans. People may get infected through direct contact with an environment contaminated with the urine of infected animals. 

Clinical signs of leptospirosis in humans include fever, headache, decreased appetite, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, diarrhoea and rash. Without treatment, leptospirosis may also be fatal in humans.

Melioidosis 

Melioidosis is a disease caused by Burkholderia pseudomallei, another bacterium. It is present in South-east Asia and can cause disease in both animals and humans.

Infection usually occurs through direct contact with contaminated soil or water. Animals may become infected by ingesting contaminated soil or through contact with skin wounds exposed to the bacteria. Animals with weakened immune systems are at higher risk.

Heavy rainfall may also increase infection of melioidosis. Direct transmission between animals or from animal to human is rare. Most human infection cases are a result of contaminated soil or water, rather than animal contact.

This bacterium has been shown to affect a wide variety of animal species, including dogs, cats, rodents, reptiles, birds and fish.

Symptoms of melioidosis in animals vary. Affected animals may demonstrate signs of diarrhoea, pneumonia, loss of appetite or abscesses. As melioidosis symptoms resemble those of other diseases, laboratory confirmation is required for diagnosis.

What you can do

If you suspect that your pets are suffering from leptospirosis or melioidosis, you should consult your veterinarian promptly.

To help protect against these infections, pet owners should: 

1. Vaccinate your dog against leptospirosis. The vaccine does not provide 100 per cent protection against leptospirosis because there are many strains that cause the disease. It also does not provide immunity against all strains. 

But it can reduce the chances of a dog being infected and help prevent the shedding of bacteria in the dog’s urine. Adult dogs at risk are recommended to be revaccinated annually after their primary course of vaccination.

Unlike leptospirosis, there is no available vaccine for melioidosis.

2. Reduce your animal’s exposure to stagnant water, puddles or soil that may be contaminated with bacteria, especially if there are open wounds. 

3. Keep rodent problems under control at your premises, as rodents are considered a source of infection of leptospirosis.

4. Practise good hygiene if your pet is infected with leptospirosis or melioidosis. Avoid direct handling or contact with your pet’s urine or blood. If necessary, wear protective coverings – such as gloves – and wash your hands with soap after handling your pet or anything that might have its excrement on it, such as tissues.

Clean surfaces that may be contaminated or contain urine from an infected pet using antibacterial cleaning solutions or household bleach. 

As these are notifiable diseases, suspected and confirmed cases of leptospirosis and melioidosis must be reported to the National Parks Board (NParks) by veterinarians.

NParks monitors these cases and investigates suspected clusters, working with the One Health agencies in Singapore when potential outbreaks are identified. 

For example, the Animal & Veterinary Service (AVS), a cluster under NParks, was notified of four confirmed cases of leptospirosis in dogs in the Shunfu neighbourhood in January 2024 – a significant increase compared with baseline.

In response, AVS worked together with licensed veterinarians to increase vigilance against this disease. The outbreak was resolved by early February 2024, with no further cases reported.

Investigations attributed the outbreak to wet weather conditions from November 2023 to January 2024, which facilitated bacterial survival and transmission in the environment.

With awareness and good hygiene practices, pet owners will be better equipped to protect their pets during the wet season and keep these infections at bay.