22-05-2025
Canine distemper cases on the rise
1
2
Chennai: In the Oct-Dec period every year, when the northeast monsoon is on in the city, another trend an uptick in viral infections among pet dogs unfolds quietly. Between March 2011 and Feb 2019, researchers at Teaching Veterinary Hospital of Madras Veterinary College reviewed 1,447 suspected cases.
Of these, 1,185 dogs were clinically diagnosed with Canine Distemper (CD), a contagious and deadly viral disease, recording a positivity rate of nearly 82%. Researchers from Tamil Nadu Veterinary and Animal Sciences University (Tanuvas) and University of Missouri, who conducted the study, found that CD cases rose during the northeast monsoon and winter months.
They developed a forecasting model using past disease data and weather variables such as temperature, humidity, rainfall, and wind speed.
"Community or stray dogs could be already infected, but they survive because of strong immunity. The virus spreads through their saliva and urine. When you take unvaccinated pet dogs on a walk and they come in contact with it, there are chances of them getting infected," said Naveen Kumar Viswanathan, the study's corresponding author, who worked with the research team in Tanuvas Salem, Namakkal, Chennai, and University of Missouri.
Canine Distemper is an airborne virus that also spreads through contact with infected secretions. It affects the respiratory, digestive, and nervous systems in dogs and can be fatal, especially in those not vaccinated.
Researchers observed that CD cases peak in Nov. While most cases occurred during the monsoon and winter, the patterns traced back to the summer. When temperatures and humidity rise during summer, dogs often gather in cooler places for shelter.
These groupings create conditions for the virus to spread later, as it survives longer in cooler months.
The virus is shed by infected dogs and can settle on surfaces. In summer, the virus dies off faster. But in winter and during rains, it stays active longer in the environment, leading to faster transmission.
The study reported higher CD prevalence in northern parts of Chennai, particularly Nagar and Royapuram. Researchers linked this to high population density and the practice of allowing pet dogs to roam freely. "More long-term studies linking weather and disease patterns are needed. CDV has already affected lions in Gujarat. If the virus crosses over to humans, we must be prepare," Naveen Kumar said.
