TETANUS is a bacterial infection caused by Clostridium tetani that lies latent in the environment for many years and enters the body through puncture wounds (which may be from cuts or even very tiny wounds). Once in the wound the bacteria reactivates and multiplies, producing a neurotoxin which causes highly distressing clinical signs and death in approximately 80% of cases. Clinical signs include a stiff stance and muscle rigidity including of the respiratory muscles causing respiratory distress.

Tetanus can infect many species including humans. However, horses are particularly prone to tetanus infection both by virtue of their environment and their propensity for injuring themselves.

The optimum tetanus vaccination protocol is a vaccine at 4 - 6 months of age, one a month later, one at 12 months of age then annual boosters. If your horse is not up to date with its boosters a single booster should restore immunity. If your horse is not up to date with a tetanus booster and it injures itself then it may need to be given both a tetanus toxoid as well as a tetanus antitoxoid injection to provide temporary protection while the tetanus toxoid booster takes effect.

For more information on tetanus see this factsheet:

https://www.health4horses.com.au/Global/Factsheets/H4H_Factsheet_Tetanus.pdf

STRANGLES is a bacterial infection caused by Streptococcus equi ssp. equi which is highly contagious and may lead to more chronic infection. Strangles can be spread by direct contact with infected horses (asymptomatic carriers or sick horses) as well as infected fomites such as tack, brushes, feed and water troughs. The clinical signs of strangles include upper respiratory tract infection, nasal discharge and swelling of the submandibular lymph nodes.

The strangles vaccination is only approximately 60% effective and can cause side effects such as injection site reactions, mild clinical signs of the disease and other occasional complications. However, if your horse attends horse shows, is agisted or otherwise exposed to the movement of other horses then it is recommended to vaccinate your horse.

The vaccination protocol is 3 vaccines 2 weeks apart then six monthly boosters.

HENDRA is a serious, potentially fatal virus spread by bats. It can also be spread from horses to humans and may be fatal to humans as well as horses. In Australia 3 out of 7 humans infected with Hendra have died from the virus and over 100 horses have died from the virus.

The clinical signs of infection in horses include respiratory signs (such as nasal discharge, difficulty breathing, weakness) and neurological signs (such as head tilt, twitching, wobbly gait). The virus is mutating and the clinical signs may also change over time. It is also considered likely that the virus will spread (currently the reported cases have been in Queensland and northern NSW) and the virus has been isolated in bat urine in every mainland state of Australia including in the Sydney area. The virus is also increasing in incidence. For example there were 5 cases between 1994 and 2004 and 33 from 2011 to 2014.

Vaccination is the most effective way to reduce the risk of Hendra and due to the serious nature of the infection to both horses and humans it is recommended that horses should be vaccinated for this virus. If an unvaccinated horse displays clinical signs potentially consistent with Hendra then the treating vet may decline to treat your horse on the basis that it is unsafe to do so. Hendra is a notifiable disease and if your horse contracts it then even if your horse does not die from Hendra there is a high likelihood that it will be euthanased.

Adult horses being vaccinated for Hendra for the first time should receive a vaccine followed by another one three to six weeks later, a booster 6 months after that followed by annual boosters.

The vaccine has been approved for use in pregnant mares but it is recommended that the vaccine not be given in the first 6 weeks or the last 2 weeks of pregnancy.

The vaccine has been administered over 440,000 times in Australia with adverse effects (usually mild and transient) reported in 0.28% of cases. These adverse reactions are generally typical of vaccinations (including human vaccinations) such as injection site reactions, lethargy, muscle soreness and loss of appetite. The vaccine contains no live Hendra virus and it is impossible to contract Hendra from the vaccine.

For more information on Hendra please see the following factsheet:

https://www.health4horses.com.au/Global/Factsheets/H4H_Factsheet_Hendra.pdf

BROODMARES and FOALS should be considered for other vaccinations such as those against Equine Herpes Virus, Rotavirus and Salmonella. Give us a call if you would like to discuss these vaccines.