Leptospirosis is a bacterial disease that can affect both animals and humans.
It can be transmitted through cuts and abrasions on the skin, or through water contaminated with the urine of infected animals.
Symptoms in dogs include fever, vomiting, diarrhoea, jaundice and inability to urinate.
Symptoms in humans include fever, headache, decreased appetite, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, diarrhoea and rashes.
Infected dogs may be treated with antibiotics but may succumb to infection. Without treatment, leptospirosis may be fatal.
Rodents are considered the primary source of infection to human beings.
A vaccination is available to prevent leptospirosis infection. Although it does not guarantee 100 per cent protection, it can reduce the chances of infection.
Dr Sing Kong Yuen, veterinary surgeon with Toa Payoh Vets, said that pets may become susceptible to leptospirosis when owners become negligent in sending them for vaccinations.
"When their dogs are just puppies, they may be very vigilant in sending them for yearly vaccinations.
"But as their dogs grow older, some owners may stop taking them for vaccinations, even though we send them reminders to do so."
Dr Sing recommends that owners closely supervise their pets to keep them from playing in unclean places, or from hunting and eating rats.