INNOCENT VICTIMS

by Dr Anne Fawcett

Horses at an RDA Centre in New Zealand developed painful symptoms suspected of being related to a nearby illicit drug laboratory.


A mysterious illness affecting horses at a New Zealand riding school has been linked to gas from an illicit methamphetamine laboratory nearby.

The mystery began when a horse at Rotorua’s Riding for the Disabled Hannah’s Bay property developed a rapidly swelling head.

RDA Senior Coach and Horse Manager Kate Honour initially thought the horse had swallowed a bee or wasp and suspected it was having a sudden, generalised allergic reaction (anaphylaxis). But the following morning, another seven horses developed the same symptoms.

All eight were examined by a local veterinarian who was interviewed on condition of anonymity. The horses were observed to have acute swelling of the face, with massively enlarged lymph nodes. All had ulcers and blisters on the lining of the nasal passages. Aged between four and 35, all were fully vaccinated. In the absence of an obvious cause, blood was taken for testing and the horses were treated symptomatically with steroids and antihistamines. Blood results of four horses were consistent with an allergic reaction, but did not point to a specific medical condition.

Weed Identification
The RDA, who had used the same property for over 20 years, had staff comb the paddock looking for wasps, bees, ants or plants that may have caused the condition. The horses, mostly mixed breed, were grazed as a herd and rotated through paddocks of largely mixed meadow grasses with white and red clover. Weeds identified in the paddock included dandelion, dock and blackberry. Everything you can think of - right down to the proteins in weeds and grasses in the paddock - was checked. As an added precaution, horses were relocated to a short-grassed paddock and hand fed hay. However, despite thorough investigations they failed to identify a culprit.

Initially, all horses appeared to improve with symptomatic treatment. Then two weeks later, the veterinarian was called to the property to assess another horse that had developed the same signs overnight. In a matter of hours, an additional eight horses developed signs. The only common factor that could be found with the previous episode was the sudden overnight drop in temperature and cold Southerly wind. This lead veterinarians and RDA staff to consider the possibility of an aerosolised toxin, such as aviation fuel from nearby Rotorua airport or overflow from a septic tank.

Hashish In The Air
Staff at the facility had noticed the scent of hashish, and a strong chemical smell, originating from an adjacent property. They suspected the smell was linked to the production of illicit drugs. It was just fortunate that they didn’t have to wait for confirmation as, acting on an unrelated tip about a firearm, Rotorua police raided the property the next day, stumbling across a methamphetamine laboratory.

The laboratory was located approximately 200 metres from the paddock where the horses grazed. The occupants of the house were attempting to destroy the laboratory by burning it, releasing more gases in the process. One of the by-products of methamphetamine production is hydrogen chloride gas, known to cause inflammation of the respiratory tract in rats. Other effects include shortness of breath and poor oxygenation of the blood. If a pregnant rat is exposed to the toxin the unborn young may be killed and those carried to term may have a low birth weight.

Few reports are available on the effects of HCl exposure on humans, but occupational exposure has been reported to lead to bleeding and ulceration of mucous membranes, and dental erosion. A policewoman who entered the property was admitted to Rotorua hospital after feeling nauseous. All of the officers who entered the house, as well as the occupants of the house, were decontaminated in emergency showers set up by the Fire Service.

Honour suspects that the gas may have leaked from the property and deposited on paddocks where the horses graze. Further investigation revealed the presence of the nasal mucosal lesions in horses grazing neighbouring properties.

All affected horses are now on the road to recovery. Within weeks of the episodes, the swelling began to subside. Affected animals remained sore in the head and neck region and the nasal lesions have not completely resolved.

Having seen the effects of the mysterious gas on horses, locals are concerned about possible human health repercussions. The likelihood of compensation however, is low as there is currently no definitive test for HCl toxicity. The next step is to find out if there are horses on other properties adjacent or nearby crystal methamphetamine laboratories that develop similar lesions.

The episode has been devastating for the RDA, which receives no Government funding, as they had not budgeted for something of this magnitude to affect their working horses.
“We have over 110 riders,” said Honour, “plus support staff, parents and volunteers who are devastated.”

The RDA is welcoming donations and letters or support, which can be sent to Rotorua RDA, PO Box 7416, Te Nage, Rotorua, New Zealand.