Dr David Gething
Updated: Aug 21, 2019
Hong Kong's Deadly Killer
Every year, we see multiple infections of leptospirosis in our clinic.
Leptospirosis is a bacteria-like organism that is usually spread by rat urine. Rats live in the bushy areas around The Peak and after heavy rains, their urine will be washed down into streams and waterways around Mid-Levels and Pokfulam. There have been some cases reported in Sai Kung as well.
In every case of Leptospirosis we have seen, the affected dogs have had a history of playing in and drinking fresh water from streams. Owners are often under the assumption that if the water is running, it is clean and good to drink. However, this is definitely not the case.
Leptospirosis will usually result in liver and kidney failure. The early signs are innocuous - sometimes vomiting and diarrhoea are seen. However when the signs of the kidney and liver failure appear it is usually too late for the treatment to have any effect - the damage has already been done. The organisms are actually killed very quickly with antibiotics, but the damage is so severe that most dogs don't recover. Once the symptoms appear, it is usually too late.
There are two types of Leptospirosis vaccine. One is included in the annual DHPPiL combination vaccine that all dogs receive. It is completely ineffective against the local Leptospirosis. The other is called Leptovax 4, which protects against multiple serovars (types) of Leptospirosis. Upon receiving the vaccine, dogs will develop antibodies to Leptospirosis that will boost an immune response during infection. It is possible for dogs who have received the Leptovax 4 to still contract the disease, however they will have a better chance of fighting the infection than non-immunized dogs.
However, the most effective measure to avoid Leptospirosis is to never let dogs play or drink from running water anywhere in Hong Kong. Puppies should be taught not to drink from streams and all dogs should be kept on a leash around watercourses if they are prone to drinking and playing in them. Owners should make sure they take drinking water for their dogs during walks so the dogs continue to have access to water.
If you notice your dog is off colour and the dog has a history of playing in or drinking from fresh water streams, they should call us immediately. Make sure you mention your concern about Leptospirosis - early signs often look like a regular case of gastroenteritis and if the vet doesn't know about the history they probably won't suspect Leptospirosis. It's much better to be safe than sorry in these cases.
Although it is a devastating disease, owners should keep in mind that it is still relatively rare. In Hong Kong this summer there have apparently been 12 cases. Contrast this to hundreds of cases of Tick Fever. And if you keep your dogs out of waterways, the chances of catching the disease are extremely low.