Cover image courtesy of The Image Is Everything
New Zealand's thoroughbred industry remains on heightened alert as authorities work to contain a strangles outbreak that continues to affect and threaten properties in the wider Waikato area.
As of Monday July 6, the number of affected properties has increased from seven to 13 over the past week, with 12 confirmed properties, four suspected properties and one historical case. The outbreak is primarily affecting training and pre-training establishments, with some stud properties also impacted.
At present, the outbreak remains isolated to the wider Waikato region, with one linked Auckland property that is reported as being well contained. The property does not send horses to communal training facilities or racetracks and has a direct link to the Waikato outbreak.
Importantly, the cases remain confined to the thoroughbred population and are largely restricted to one region, with no evidence of transmission into other horse populations.
As the industry works to contain the outbreak, the New Zealand Equine Health Association has outlined the key information horse owners need to know, while New Zealand Thoroughbred Racing (NZTR) has introduced additional health requirements for horses competing at races and trials.
What is strangles and what do horse people need to know?
Strangles is a highly contagious bacterial infection caused by Streptococcus equi equi, affecting the upper airways and lymph nodes around the head and neck.
Owners should note there is a closely related subspecies, Streptococcus equi zooepidemicus, however it is a different organism and does not cause strangles. Laboratory results should specifically identify the subspecies.
Most horses recover within four to six weeks with appropriate care, but early detection remains critical.
A high temperature is usually the first sign of infection, often appearing before any other clinical symptoms. Other warning signs include lethargy, loss of appetite, thick yellow nasal discharge, coughing and swollen lymph nodes beneath the jaw that may abscess.
Symptoms of Strangles | Image courtesy of American Association of Equine Practitioners
Any horse developing a fever and nasal discharge after travelling or mixing with unfamiliar horses should be treated as a potential strangles case until advised otherwise by a veterinarian.
If infection is suspected, owners should immediately isolate the horse before contacting their veterinarian. Horses should not be assumed to be free of infection simply because they appear clinically improved, with around one in 10 recovered horses becoming silent carriers capable of spreading the disease.
Owners are also advised to not to administer antibiotics unless specifically recommended by a veterinarian, as they can delay abscess development, prolong illness and reduce natural immunity. Supportive nursing care remains the primary treatment in most uncomplicated cases.
Stringent biosecurity is the best defence
Strong biosecurity practices continue to be the industry's best defence. New or returning horses should be quarantined for 14 to 21 days, temperatures monitored twice daily, equipment should not be shared between horses and transport, clothing and equipment should be thoroughly cleaned and disinfected.
Vaccination remains an important preventative measure, particularly for travelling horses, although horses that are sick or have recently been exposed should not be vaccinated without veterinary advice.
Where active cases occur, horses should be separated into infected, exposed and clean groups, with separate equipment and, where possible, separate handlers used for each group.
The New Zealand Equine Health Association has also urged owners not to let the stigma surrounding strangles discourage reporting, emphasising that early communication remains one of the most effective ways of limiting the spread of the disease.
New Zealand Veterinary Association Head of Veterinary Services Holly Blue emphasises that vigilance remained essential.
“Early detection and strict biosecurity measures, including isolation and monitoring horse temperatures, are critical to limiting the spread,” Blue told farmersweekly.co.nz.
Holly Blue | Image courtesy of Worm-Ed
“Early detection and strict biosecurity measures, including isolation and monitoring horse temperatures, are critical to limiting the spread.” - Holly Blue
Blue said the outbreak remained geographically contained.
“At this stage, the outbreak remains confined to the thoroughbred population and is largely restricted to one regional area.
“While everyone involved with horses should remain vigilant and continue to maintain good biosecurity and disease control practices, there is currently no evidence of transmission into other horse populations.”
She said horse owners should continue monitoring closely for symptoms.
“Strangles spreads through direct contact with infected horses, or personnel such as groomers, trainers and even domestic pets that have been in contact with them, as well as contaminated equipment, clothing, footwear and hands, and infected nasal and oral secretions.
“It's critical that horse owners monitor for early signs of the disease, including fever, loss of appetite, depression or dullness, coughing, thick nasal discharge and swollen glands.
“Ultimately, a thermometer is your best friend right now. If you notice a fever especially after movement, travel or contact with unfamiliar horses, treat it as strangles until proven otherwise.
“Ultimately, a thermometer is your best friend right now.” - Holly Blue
“Isolate the horse immediately and contact your veterinarian for diagnosis and advice, disinfect all equipment and clothing after contact with infected or suspected cases and horse owners should also talk to their veterinarian about vaccination, which can help reduce the severity of disease.”
NZTR introduces additional requirements
To minimise the risk of strangles spreading while allowing racing and trialling to continue safely, NZTR has introduced additional health requirements for every horse accepted to race or trial.
The measures take effect from the Cambridge Synthetic race meeting on Thursday, 9 July 2026, and will remain in place until further notice.
Cambridge Synthetic track | Image courtesy of Trish Dunell
All accepted runners must have their temperature recorded twice daily, with a minimum of eight hours between readings, while trainers must complete a Strangles Health Declaration confirming the horse is clinically well.
Recognising the short lead-in time, NZTR has eased the initial monitoring period for meetings this week. Horses racing or trialling must have temperatures recorded for as many consecutive days as reasonably practicable, with a minimum of two days' monitoring before competing.
From Sunday, 12 July, five consecutive days of temperature monitoring will become mandatory.
SAA blood testing required
Serum Amyloid A (SAA) blood testing will also be required for horses stabled within the greater Waikato region, horses recording a temperature above 38.5 degrees Celsius during the monitoring period and horses from any property with a confirmed strangles case. The test must be completed within two days of racing or trialling, with results submitted by 7.30am on raceday where required.
Collecting blood for SAA screening | Image courtesy of VMRD
Each accepted runner must also be accompanied by a completed Strangles Health Declaration, including temperature records and SAA results where applicable. Failure to provide the required documentation will result in the horse being scratched for non-compliance, with NZTR and the Racing Integrity Board also conducting spot checks to verify SAA test results.
To further reduce the risk of disease spread, NZTR has recommended that jump-outs and daily trackwork be limited to horses that are regular users of the same training facility, with horses not transported between regions to participate.
“We are not expecting that we will be forced to stop race meetings at all at this stage,” NZTR’s General Manager of Racing Mitch Lamb told the New Zealand Herald on Tuesday. “But to ensure that doesn’t happen, we have put new guidelines and protocols in place, and our advice from the experts we are dealing with is these protocols could stay in place for at least the next month.”
NZTR said it would continue working closely with the Racing Integrity Board, NZTBA, the Equine Veterinary Branch of the NZVA, the Equine Health Association, clubs, veterinarians and other industry stakeholders, with a further update to be provided next week or earlier if required.
"We want and expect horse people to meet their obligations and do everything they can to stop any further spread and that should enable us to keep racing." - Mitch Lamb
“There is a real element of trust in this and everybody working together,” Lamb said. “We want and expect horse people to meet their obligations and do everything they can to stop any further spread and that should enable us to keep racing.”
