The Impact of Mosquito-Borne Diseases: EEE and WNV in Michigan

Mosquito-borne diseases, particularly Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV), remain a significant threat to both animal and public health in Michigan. This article explores the recent cases, symptoms, and preventive measures necessary to combat these diseases, highlighting the importance of vaccination and effective mosquito control.

Recent Cases in Michigan

In 2024, Michigan has reported several alarming cases of EEE and WNV. For instance, three notable cases were identified across Kalamazoo, St. Joseph, and Allegan counties:

  • Kalamazoo County: A 2-year-old filly was unfortunately dually infected with EEE and WNV despite being vaccinated earlier in April 2024. The severe symptoms led to the horse being euthanized.
  • St. Joseph County: An unvaccinated yearling Standardbred colt tested positive for WNV, displaying symptoms such as fever, leaning, and recumbency before being euthanized.
  • Allegan County: A 5-year-old Quarter Horse gelding with incomplete vaccination records tested positive for EEE and showed symptoms like ataxia and seizures. This horse, too, had to be euthanized.

Additionally, the state's residents have also fallen victim to WNV, with 14 cases reported as of September 13, 2024. Among these, one individual from Livingston County contracted the disease outside Michigan.

Understanding EEE and WNV: Symptoms and Risks

Eastern Equine Encephalitis (EEE)

EEE is a rare but highly fatal disease caused by a virus carried by infected mosquitoes. The disease primarily affects horses but can also have severe consequences for humans, particularly those over 50 and under 15 years old. The mortality rate in humans is about 30%, with survivors often suffering significant neurological damage. In horses, EEE is almost always fatal if untreated, making it a critical concern in late summer to early fall.

West Nile Virus (WNV)

WNV is another mosquito-borne disease affecting both horses and humans. While less fatal than EEE, it still poses substantial health risks. In horses, WNV symptoms include muscle twitching, sensitivity to touch, and asymmetrical ataxia. With supportive care, recovery is possible, though the disease still carries a notable mortality rate. In humans, WNV can manifest as mild symptoms like headaches and body aches to severe complications, including brain swelling.

Preventive Measures to Combat EEE and WNV

Investing in preventive measures is crucial to protect both animals and humans from these devastating diseases.

For Animals

  • Vaccination: Consult with a veterinarian about vaccinating horses against EEE, WNV, and other mosquito-borne diseases. Vaccination is essential, particularly in high-risk areas.
  • Mosquito Control: Eliminate standing water around homes and stables by filling in puddles, repairing eaves, and changing water in buckets and bowls daily. Placing livestock in barns under fans and keeping pets indoors during peak mosquito activity are effective measures.
  • Insect Repellents: Using EPA-approved insect repellents on animals helps prevent bites.

For Humans

  • Insect Repellents: Apply insect repellents containing DEET or other EPA-approved products to exposed skin or clothing as per the manufacturer's instructions.
  • Clothing and Screening: Wearing light-colored, long-sleeved shirts and pants, and maintaining window and door screening keep mosquitoes at bay.
  • Mosquito Breeding Sites: Regularly empty water from breeding sites like buckets, unused kiddie pools, old tires, and other water-holding containers.

Testing and Funding

To assist with the identification and management of these diseases, the Michigan Department of Agriculture and Rural Development (MDARD) offers funding to cover testing costs for suspect animals. This funding supports any Michigan animal exhibiting signs of neurological disease or sudden death, provided the testing is pre-approved by MDARD and samples submitted to the Michigan State University Veterinary Diagnostic Laboratory (MSU VDL).

Conclusion

The recent cases of EEE and WNV in Michigan underscore the ongoing risks these diseases pose to both animal and public health. By remaining vigilant in vaccination, mosquito control, and various preventive measures, we can mitigate these risks. Understanding these diseases better and implementing effective strategies can substantially protect our animals and communities.

Further Research Topics

  • Impact of Vaccination on Equine Health: Investigate the effectiveness of various vaccines for mosquito-borne diseases in horses.
  • Climate Change and Mosquito-borne Diseases: Examine how changing climate patterns influence the spread of diseases like EEE and WNV.
  • Advances in Equine Disease Detection: Explore new technologies and methods for early detection and prevention of equine diseases.
  • Treatment and Management of EEE and WNV in Horses: Study the latest treatments and management practices for horses infected with EEE and WNV.
  • Public Health Implications of EEE and WNV: Investigate the zoonotic potential and measures taken to protect human health.

Addressing these topics can enhance our understanding and response to these infectious diseases, ultimately improving public and animal health.

References: Content sourced from TheHorse.com and EDCC.