[Toxinology of bovine paraplegic syndrome].

A clinical entity named "Bovine Paraplegic Syndrome" ("Síndrome Parapléjico de los Bovinos") has spread alarmingly, in the cattle growing areas of the central and eastern plains of Venezuela. Approximately four million cattle are bread in the area were the disease occurs. The mortality index due to the disease ranges 5 to 25% of the animals at risk, mostly cows, pregnant or lactating. The principal characteristic of the bovine paraplegic syndrome is decubitus, ventral or sternal, in animals that make vane efforts to stand when stimulated. The diagnosis is established ruling out, clinically and with laboratory findings, that the animals are suffering known diseases with similar symptoms such as paralytic rabies, botulism and blood parasites such Trypanosoma sp., Babesia sp., and Anaplasma sp.. Death occurs always, usually after few days, and to this date there is no known treatment able to save the sick cows. In this work, we describe results that suggest the presence of a toxin in the cattle suffering and prone to suffer the syndrome; it is a natural toxin produced by ruminal bacteria. In squid giant axons under voltage clamp conditions, this toxin is very specific to block sodium current during nerve electrical activity.