Black Widow Spider Bite Poisoning in Cats

Black widow Spider bite poisoning is extremely dangerous and often fatal for cats. If symptoms are observed or it is suspected a bite has occurred, immediate medical attention is required. 

The black widow is a spider of the Latrodectus genus, which is known for its dangerous venom and signature markings. The females of the species are considered to be the most venomous spider found in North America. Their characteristic markings include an easily recognizable red or orange hourglass shape on their black or dark brown body. Envenomation occurs when the spider bites and can be very dangerous and even deadly to companion animals and people. Cats are very sensitive to the venom and can experience severe symptoms very quickly.

The symptoms related to black widow bite poisoning present quickly, usually within the first few hours after the bite was received. Symptoms include pain and muscle issues including paralysis, respiratory issues, and death. Cats are especially sensitive to the venom, so symptoms are often severe and rapidly progress. 

Symptoms Include:

• Severe pain
• Howling or other loud vocalizations
• Muscle rigidity
• Tremors and cramping
• Uncoordinated movements
• Inability to stand
• Weakness in the limbs
• Paralysis
• Seizures
• Trouble breathing
• Respiratory collapse
• High blood pressure
• Increased heart rate
• Drooling or excessive salivation
• Vomiting
• Diarrhea
• Restlessness
• Seizures
• Death

Types

Widow spiders come in several types, all of which contain powerful venom that acts as a neurotoxin. The black widow spider is the most common and toxic version, but other types that can cause similar effects include: 

• Western black widow (Western U.S.)
• Brown widow (Southern U.S.)
• Red widow (Florida)
• Northern widow (Northeast U.S.)

This type of poisoning is a result of envenomation or a dose of venom. This usually occurs during a spider bite, although not all black widow bites contain venom. A single bite can deliver a lethal dose of toxin to a cat or other companion animal. The venom contains a neurotoxin that attacks the nerves causing pain and muscular reactions. The spider can be found throughout the continental U.S. and into Canada. Your cat could encounter the spider indoors or outdoors, as it can comfortably make its home just about anywhere. Occasionally poisoning can occur through ingestion. If this is the case, the cat may vomit up the spider.

Visual confirmation of the spider or the spider bite is helpful in accurately diagnosing the cat’s condition. Advise your veterinarian if there have been any spider sightings or signs of black widows in the area. If a spider was vomited up, bring it with you. In cases where this visual aid is not available, a diagnosis will be made based on symptoms and other clinical signs. Discuss the symptoms you have observed and the timeline of their onset with the doctor. Abdominal rigidity without tenderness and muscle spasms followed by paralysis are most often associated with a black widow bite. The veterinarian will look for this and other signs during a physical examination. Paralysis, pain, and related vocalization, breathing, and blood pressure can all point to envenomation, but are also possible with other conditions. This can make accurate diagnosis difficult. Testing the levels of serum muscle enzyme activities may also help determine if symptoms are being caused by a widow bite.

Black widow spider bites require medical treatment, or death is certain. A specific antivenin must be administered to combat the effects of the spider’s neurotoxin. Even after being dosed with the antivenin, the cat’s prognosis may be uncertain. Other methods may be used to treat associated symptoms. Treatments used in conjunction with the antivenin include:

• Analgesics: A common type of painkiller, this medication will help control the cat’s pain and reduce inflammation. Your veterinarian will determine the safest dose to use on your pet. 
• Muscle Relaxers: One of several types of muscle relaxing medications may be necessary to combat seizures, cramps, and paralysis. Accurate dosing will reduce the risk of side effects and complications. 
• Oxygen Therapy: To treat respiratory problems, oxygen therapy may be needed. Tubing, masks, or an oxygen cage may be used to aid breathing and maintain proper blood oxygen levels.

Recovery may not be certain for several days after initial treatment has begun. Partial paralysis and marked muscular weakness can persist for several days or even weeks. The cat will require hospitalization, medication, and observation until the most severe symptoms have subsided. Once on the road to recovery, the cat may still require special care. Monitor their eating habits closely and make sure they get enough water. Continue to provide prescribed doses of medications and follow all of the veterinarian’s aftercare instructions. Weakness, restlessness, and general pain can continue for months before the cat will make a full recovery.