Intravenous administration of equine-derived whole IgG antivenom does not induce early adverse reactions in non-envenomed horses and cows.

The research article examines how the use of equine-derived antivenom in treating snakebite envenomings in horses and cows does not visibly induce any <adverse reactions, when compared with humans where such treatments can lead to responses like fever, vomiting, and diarrhea.

Research Purpose and Methodology

In this research, the aim was to understand the likely adverse reactions that could occur when equine-derived antivenom is administered to non-envenomed horses and cows. This understanding was necessitated by the perceived early adverse reactions in humans when administered with similar treatments for snakebites.

• The antivenom in question for this study was a polyspecific antivenom, made entirely of Immunoglobulin G (IgG) purified from horse plasma. The method of purification used was caprylic acid precipitation.
• The animals used for this study were non-envenomed horses and cows. The group consisted of 47 horses and 20 cows.
• The antivenom was administered intravenously at a dose of 0.4 mL/kg, matching the dosage rate with that of humans.

Findings and Observations

The result of the study showed that unlike humans, none of the non-envenomed animals showed any indication of early adverse reactions. Additionally, the experiment also recorded that there were no late adverse reactions such as serum sickness observed over a period of 40 days after the antivenom was administered.

• For humans, common early adverse reactions upon administration of this formulation included diarrhea, fever, vomiting, accelerated heartbeat or tachycardia, generalized rash, tachypnea (rapid breathing), and urticaria (hives). These reactions were seen in about 15-20% of patients.
• This contrasted significantly with the observations from the test animals, where no adverse physiological reactions were recorded.

Conclusion

The conclusion from this study was primarily that in addition to physicochemical characteristics of the antivenom formulation, there are other factors yet unknown that influence the occurrence of adverse reactions in humans that are treated with antivenoms derived from equines. This can be seen from the lack of such reactions in horses and cows, implying that the reactions in humans could be more related to human physiology as opposed to any chemical issues with the antivenom itself.