Cardiotoxicity, inflammation, and immune response after rattlesnake envenomation in the horse.

The study investigates the presence of heart abnormalities in horses following a rattlesnake bite by comparing an array of samples from bitten horses with healthy controls. The research suggests that such bites often result in heart damage and irregular heartbeat, potentially stemming from the body’s inflammatory response rather than the venom itself.

Research Objective and Methodology

This research undertakes a clinical examination of 20 adult horses that have suffered rattlesnake bites, with the aim to detect and understand potential cardiac damage. For comparison, the study also uses 6 unaffected, normally healthy horses.

• A variety of samples were collected from the bitten horses, including swabs from the bite site, blood, and urine. This allowed detection of venom in the body and its possible relationship with cardiac damage.
• Continuous ECG (electrocardiogram) recordings were obtained over a 24-hour period for both the bitten horses and healthier controls, to assess and compare any irregular heart rhythms.
• The collected plasma samples were tested for markers of heart damage (cardiac troponin I, or cTnI), while the serum samples provided data on inflammatory response (through the measurement of cytokine TNFα) and anti-venom antibodies.

Results and Analysis

The results found a number of cardiac irregularities in the bitten horses.

• 40% of the bitten horses (8 out of 20) showed signs of heart muscle damage, as indicated by increased levels of cTnI.
• 70% of the bitten horse group (14 out of 20) demonstrated irregular heart rhythms on the ECG recordings.
• The study found a positive correlation between the cTnI and TNFα, suggesting an interaction between heart damage and inflammation.
• Horses with higher levels of cTnI were more likely to have higher anti-venom antibody titers, indicating a robust immune response.
• There was no detectable link between the concentration of venom and levels of cTnI, anti-venom antibodies, TNFα, or the presence of arrhythmias.

Conclusions

The research concludes that cardiac issues are common after rattlesnake bites in horses. The findings suggest that these complications might not directly stem from the venom itself, but rather from the horse’s immune response and the associated inflammation. Therefore, monitoring for signs of cardiac damage and dysfunction is recommended whenever a horse suffers a rattlesnake bite. The study also encourages long-term follow-up to catch any potential delayed cardiac dysfunction.