Black Widow Spider Bite Poisoning Average Cost

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Average Cost


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What is Black Widow Spider Bite Poisoning?

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.

Symptoms of Black Widow Spider Bite Poisoning in Cats

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


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.)

Causes of Black Widow Spider Bite Poisoning in Cats

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.

Diagnosis of Black Widow Spider Bite Poisoning in Cats

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.

Treatment of Black Widow Spider Bite Poisoning in Cats

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 of Black Widow Spider Bite Poisoning in Cats

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.

Black Widow Spider Bite Poisoning Questions and Advice from Veterinary Professionals

Normal house cat - was stray
15 Months
Critical condition
1 found helpful
Critical condition

Has Symptoms

Lost appetite, dizzy and weak
Drink a lot of water & then stop
Started to vomitting
& eventually stop using the toilet

A few weeks ago (+- 4 weeks ago)on a Thursday he was outside, next moment he came running back into the house and scratching just underneath his left eye.
By Monday I had to rushed him to the vet to have a look at that. He cut it open and the ether and stuff that came out of there clearly showed there were bad infection. For 3 weeks I drained it but you could see he started to loose weight and he was just not him self.
By 30th June - I picked up, he didn't eat any more and you could see he was not well. I rushed with him to the vet on Sunday by that time it was bad - he was very weak didn't eat or drinking water. Dr. 1st test him for Panleukopenia - it showed negative. You could see he had tummy ache, dizzy and I let him feel on the side of his body you could feel something like sists. He then test his kidney's - and the colour of his urine was like brown red yellow - very difficult to explain. So he also mentioned it might be his liver. He asked me to bring him back on the Monday afternoon so that they can do some scans and more tests.
I rushed him back on Monday morning - he started to vomit not taking any chances. The admitted him and that afternoon the Dr. phoned and said his liver count is up but not too seriously they will monitor him.
I visit him everyday and each and every time it was he his not doing better but not getting worse. On Saturday morning I've got a call from the vet - he suggested we euthanised him he don't have any hope. He had hepatitis & yellow jaundice and his liver now is not functioning.
I mentioned on several occasions everything went down hill with my cat since something bitten him under the eye (the area under the eye where you could see he was bitten basically had a whole in - it looks like if the flesh around it had rotten) is it possible that it was a Black widow spider and the poison has spread through his little body?

The thing is I mentioned to the vet that since he had t

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3320 Recommendations
From your description it sounds more like a brown recluse spider than a black widow, but that would explain the wound on the face as well as the liver failure and urinary changes; there is no antidote for brown recluse spider poisoning, treatment is mainly supportive and symptomatic. Regards Dr Callum Turner DVM

Thank you very much Doctor, now I can let it be and accept it.

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