Black Widow Spider Bite Poisoning in Dogs

What Is Black Widow Spider Bite Poisoning in Dogs?

Widow spiders are found worldwide, mostly in tropical and temperate regions. 

The incidence of black widow spider bites in dogs is unknown, but it is noteworthy because a single bite can be lethal to a dog. Black widow spider venom is highly toxic, typically exceeding the toxicity of most snake venom. Black widow venom contains a neurotoxin that causes severe muscle spasms and tremors, which can progress to respiratory distress, paralysis, and even death.   

A venomous spider bite is a medical emergency. If you witness or suspect your dog has been bitten by a black widow, take them immediately to your local veterinary emergency hospital.   

Symptoms of Black Widow Spider Bite Poisoning in Dogs

Clinical signs of black widow spider bite may occur as quickly as 30 minutes after the bite but can worsen over the next 8 hours. Acute signs often resolve in 48-72 hours, but weakness and lethargy can persist for several months. Common clinical signs include:

• Vomiting/Drooling

• Diarrhea

• Lethargy

• Rapid weight loss

• Vocalization such as crying, whining, or howling

• Muscle spasms, which can be severe

• Pain, mostly associated with muscle pain

• Abdominal cramping

• Trouble breathing

• Elevated heart rate

• Elevated blood pressure

• Agitation and restlessness

• Trouble walking, stumbling

• Tremors or seizures

• Paralysis

Causes of Black Widow Spider Bite Poisoning in Dogs

Black widow spiders are generally shy, but they will bite if encountered by curious pets. Black widow spiders like to make their homes around buildings. Once inside houses, they often choose undisturbed, cluttered areas such as basements, crawl spaces, dark corners, or under cabinets. Outside, black widow spiders often nest in wood or leaf piles, under stones, or in sheds and garages. Their webs are messy and irregular, typically located at ground level. 

There are many factors that determine the severity of clinical signs associated with black widow spider bite poisoning in dogs, including:

• How much venom is received (black widow spiders can control the amount of venom injected)

• Size of the spider (the bigger the spider, the more venom it has)

• Time of year (affects venom toxicity)

• Size of the dog (smaller dogs will get a larger ratio of venom)

• Age of the dog (pediatric and geriatric dogs are often more affected)

• Bite location

• Concurrent health problems of the bitten dog

What Does a Black Widow Look Like?

anaphylactic reactions in dogs. For this reason, the antivenom is likely reserved for high-risk or severely affected dogs. 

Recovery and Management of Black Widow Spider Bite Poisoning in Dogs

Early and aggressive care is crucial for successful treatment of black widow spider bite poisoning in dogs. The prognosis can vary based on how much toxin was injected through the spider’s bite, time from bite to initiation of treatment, and individual pet’s response to therapy. Response to treatment is often uncertain for the first 2-3 days after the bite occurs. 

Most dogs with moderate to severe clinical signs will remain hospitalized for 2-3 days for continued supportive care and medications. While most dogs that survive go on to live normal lives with minimal long-term effects, lethargy and weakness may persist for several weeks to months. 

Prevention of Black Window Spider Bite Poisoning in Dogs

Black widow spiders can be found indoors and outdoors and are typically around houses. To help decrease the odds of a black widow spider bite, reduce outdoor structures such as wood or leaf piles. It may be helpful to keep your dog on a leash when walking or hiking in areas with lots of logs or rocks where spiders may be hiding.

In the house, try to keep your dog out of areas where spiders may live­, such as crawl spaces and basement corners. The use of sticky/glue traps can be a great non-chemical way to catch spiders as well as a consultation with an exterminator service, but be sure to inform them of any pets in the household before they apply chemicals internally or externally.

Featured Image: iStock.com/Alina Nikitaeva