Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Dr Liesel van der Merwe

It is autumn and snakes are getting ready to hibernate. As the weather cools, snakes are looking for a safe warm space. They are also hunting more to store energy for the inactive winter and basking for longer periods in the warmer days when the nights are cold.

Eggs also hatch in late summer and the young snakes are looking for food and spreading out in the area. All this activity puts them at a high risk of interacting with our pets. Autumn is the season when we have the highest incidence of snake bites in our pets.

Generally, snake bites are cytotoxic or neurotoxic or a bit of a mix. The severity of the effect in the victim is related to the amount of toxin injected. Not all bites inject venom. The amount can be regulated by the snake and some bites are considered dry bites.

Puff adders are cytotoxic. Their toxin causes tissue breakdown and severe swelling and bleeding in the bite region. This can result in the animal going into shock from volume loss and also suffer from breathing problems if bitten around the throat or tongue.

Most dogs are bitten around the head and neck. Because the skin is loose here, there is room for expansion. When dogs are bitten on their legs and the toxin is injected directly into their muscles, this can cause swelling of the muscle within a non-elastic muscle sheath.

This causes compartment syndrome, which permanently damages the muscle if the muscle sheath is not incised to release the pressure. This may occur in scorpion stings and some spider bites as well. The larger dogs are less affected by this blood loss, but smaller patients can go into critical and fatal shock.

Cobras and ringhals are neurotoxic and will cause paralysis. Paralysis is only fatal if it affects the breathing muscles of the ribcage. Generally, the dog will show signs of a drooping head and salivation due to an inability to swallow. This is an emergency.

If your dog is bitten, don’t wait until it shows symptoms. Immediately take it to your vet for observation. Once this weakness becomes apparent it may be a very short time until your dog cannot breathe. Sometimes they don’t progress and just develop body weakness, but if they develop respiratory paralysis, they need to be intubated immediately and hand ventilated. 

Antivenom helps to block any toxin in the blood and decreases the uptake into the nerves. This will possibly prevent full paralysis or decrease the duration the patient is dependent on ventilation.  

However, antivenom is currently unavailable due to production stoppages at the South African Vaccine Producers (SAVP) facility and imported antivenom has to be used. No matter what the source, antivenom costs several thousand rands per vial and at best four to six vials should be administered. If possible, we try to at least administer two vials. 

A ventilator is not always necessary. Manual ventilation with the resuscitation ambu-bag can also be performed, but the vet and the client need to be prepared to do this for up to 24 hours. At the veterinary faculty we have managed several patients in this manner as we have sufficient students to assist. Much can be done here if people will offer up their time. 

The bottom line is that snake bites can be expensive to treat, and if you want to save your dog you need to act immediately and get to your nearest vet. They may not have to treat but, if necessary, it can happen immediately.