Dog owners are being warned to keep their pets away from highly toxic karaka berries and algal blooms this summer, and to contact their veterinarian immediately if they think their dog has swallowed them.

The New Zealand Veterinary Association Te Pae Kīrehe encouraged owners to walk dogs on a leash if toxic algae or karaka berries could be in the vicinity as both can make dogs incredibly ill.

NZVA Head of Veterinary Services Companion Animal Sally Cory said at this time of year pets were spending more time outdoors and have more access to things that can harm them.

"Unfortunately, dogs are attracted to karaka berries and toxic algae because of the strong smell," she says. "Even small amounts can be dangerous, so if you think your dog has eaten karaka berries or toxic algae, call your veterinarian immediately and they will advise you what to do next."

The karaka tree fruits annually between January and April, dropping orange berries containing the alkaloid, karakin, which may be poisonous to dogs.

Consumption of the berries by canines - who love their sweet taste - can lead to impaired neurological function, respiratory failure, and even death. Clinical signs can be delayed from between 24 hours and a week or more following ingestion.

Toxic algae, also known as cyanobacteria, appears in rivers and lakes as black, green, or brown slime on rocks, and as brown or black ‘mats’.

Symptoms can develop within 30 minutes and include panting, lethargy, muscle tremors, twitching, and convulsions.

"When walking your dog near fresh water at this time of year, be mindful if it’s been dry and the water is potentially stagnant, or if it has rained heavily after a dry period as this can cause algae mats to dislodge.

"Toxic algae has a strong, musty odour which dogs are attracted to and the toxic reaction can be fast. Remember if humans are advised not to swim somewhere, dogs shouldn’t swim there either."

Cory advised dog owners to keep an eye on information provided by local councils as signage may not always be installed at parks, rivers, and lakes. You can look up the potential risks of a destination by visiting Land Air Water Aotearoa.

She also urged puppy and dog owners to make sure their pets are fully vaccinated against parvovirus as cases tend to rise when dogs spend more time in public spaces when the weather's warmer.

Dogs can become infected by ingesting the virus through direct contact with contaminated faeces, surfaces, or objects, such as food bowls.

The virus can even be transmitted on footwear.

Signs of illness usually occur within three to seven days of exposure and may include severe, often bloody diarrhoea; vomiting; lethargy; decreased appetite; fever or low body temperature; rapid dehydration; and in severe cases, death.

"We have started to see an increase in parvovirus cases already this season.

"It is a highly contagious, viral disease, but it is preventable with appropriate vaccination."

Those most at risk are young (six weeks to six months), unvaccinated, or incompletely vaccinated puppies.

Similarly, vaccinations need to be kept up-to-date for canine cough (kennel cough), an infectious respiratory disease that spreads when dogs are in close contact, such as at the beach, in parks, on walks, and in boarding kennels or daycare facilities. Talk to your veterinarian to ensure your dog is protected against parvovirus and canine cough.

The summer months also bring the risk of bee sting reactions, incidents of dogs swallowing too much salt water, and grass seeds becoming lodged in ears and between toes, so keep an eye out for these too while out and about enjoying the warmer weather.

Signs of karaka poisoning include:

- Vomiting or diarrhoea

- Abdominal pain

- Reduced appetite

- Paralysis of back legs

- Loss of balance

- Convulsions

- Breathing slower than usual (which can lead to paralysis of breathing muscles).

- If you think your dog has eaten any karaka berries, contact your vet immediately.

Signs of toxic algae poisoning include:

- Panting

- Lethargy

- Muscle tremors

- Twitching

- Convulsions

- If your dog is showing any of these symptoms after being in contact with a waterway, contact your veterinarian immediately.

More information on these topics can be found on the NZVA website:

Toxic Algae

Karaka Berries

Parvovirus

Canine Cough