Black Widow Spider Bite Poisoning

Spider bites are very dangerous for cats, especially those from the most venomous species such as Black Widow spiders (Latrodectus species) and the Brown Recluse spider (Laxosceles reclusa). The venom from the Black Widow spiders is extremely potent, but it does not contain toxins that cause inflammation at the bite site. Instead, it works on the nervous system. Signs usually develop within eight hours and include painful cramping of the muscles of the chest and limbs.3 Excessive salivation, restlessness, weakness, diarrhea and vomiting may also occur. A severe pain is usually marked by howling and loud vocalizations. Seek veterinary help immediately. Restrict your cat movement until you get to the veterinary clinic. Running around or even walking will increase the blood circulation and facilitate the spreading of the venom.

Treatment for spider bites is similar to that for snake bites. Tight bandages and compression are applied around the bite site to prevent venom from spreading to the rest of the body. Cats often vomit the spider. It is very helpful for a veterinarian if the spider can be found in or around the cat's vomitus. If the spider species can be identified (for example, Black Widow spider), an effective antidot Antivenin is administered. Cats are usually hospitalized for at least 48 hours.2 The prognosis depends on the general health condition, the amount of venom injected, and the time to treatment. Death is common in cats that do not receive Antivenin. Even with treatment, your cat may be weak and have trouble sleeping for months.

Black Widow Spider Bite Poisoning


  1. Richard G. Harvey, Tim Nuttall, Patrick J. McKeever. A colour handbook of skin diseases of the dog and cat.
  2. Gary D. Norsworthy, Sharon Fooshee Grace, Mitchell A. Crystal, Larry P. Tilley. The Feline Patient.
  3. Michael E. Peterson DVM, MS. Small Animal Critical Care Medicine.

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