This is an archived Horseadvice.com Discussion. The parent article and menus are available on the navigation menu below:
HorseAdvice.com » Diseases of Horses » Poisons , Venoms & Poisonous Plants » Poisons, Poisonous Plants, and Venomous Animals »
  Discussion on Research: Black Widow Spider Bite and Horses
Author Message
Moderator:
DrO

Posted on Monday, Jan 16, 2017 - 9:02 am:

Black widow spider bites are poorly documented in horses as there are no studies and a naturally occurring bite is hard to prove. In spite of this it can be a frequently made diagnosis to explain undiagnosed diseases. Considering that the black widow is a frequent inhabitant of barns and around water buckets and troughs in the pasture it would be surprising if bites were not occurring.

The predominant clinical signs are due to the neurotoxin, a-latrotoxin, which results in the increased release of neurotransmitters. A horse bit by a black widow will look a lot like a horse that is tying up with muscle fasiculations, rigidity, and ataxia. In time this can proceed to a flaccid paralysis with an inability to stand and difficult breathing do to paralysis of the muscles of respiration. Restlessness, pain, and cramping may be present. Other diseases which may be similar looking would be colic, tetanus (rigid paralysis) or botulism (flaccid paralysis).

Diagnosis should be based on the likelihood of exposure, the above constellation of changing signs, and ruling out the other similar diseases.

Fortunately most horses will recover from a black widow bite with little more than supportive care, mainly pain relief. Calcium containing fluids should be helpful but results are not consistently seen in humans. In severe cases there is a equine antitoxin but immediate and delayed allergic reactions are possible.

The take home message is to prevent possible exposure by eliminating these pests where they hide. Frequently check around outdoor water and feed troughs. In the barn don't bother the harmless species of spiders and at the least tear down black widow nests in the barn. They are fairly recognizable by their disorganized silk nests and the characteristic egg casings. Spiders are susceptible to some of the more potent permethrins, check the label for efficacy.
DrO

J La State Med Soc. 2015 Mar-Apr;167(2):74-8. Epub 2015 Apr 15.

The black widow spider bite: differential diagnosis, clinical manifestations, and treatment options.

Shackleford R1, Veillon D1, Maxwell N2, LaChance L1, Jusino T3, Cotelingam J1, Carrington P4.
Author information


Abstract
Unrecognized and untreated black widow spider bites cause significant pain, impairment, and rarely death. The widow venom, a powerful neurotoxin known as a-latrotoxin, causes muscle pain, diaphoresis, tachycardia, flushing, and hypertension. Treatment is usually symptomatic with a combination of opioid analgesics and muscle relaxants. If symptom resolution fails, an equine IgG antiserum is available, but a high index of clinical suspicion coupled with a knowledgeable patient history often allows successful treatment, especially when the treating physician possesses awareness of this type of bite and its usual course and possible complications.
Home Page | Top of Page | Join Us!
Horseadvice.com is a BBB Accredited Business. Click for the BBB Business Review of this Horse Training in Stokesdale NC