CIV H3N8 has what origin and historical note?

CIV H3N8 has what origin and historical note?

• A. First reported in greyhounds in 2003. Since then, has spread to 41 states. It is of equine origin and is difficult to diagnose.
• B. First reported in cats in 1999; bird origin and widespread
• C. Originated in birds; spread to 15 states; not difficult to diagnose
• D. Not observed in the United States

Answer: (A)

CIV H3N8 originated in horses and jumped to dogs, with its first recognition in racing greyhounds in the early 2000s. Since then it spread widely, reaching many states across the country. Clinically, canine influenza can resemble other respiratory illnesses, so confirmation often requires specific diagnostic testing, making it relatively difficult to diagnose based on symptoms alone. This combination of equine origin, initial identification in greyhounds around 2003, broad spread, and the need for lab testing to confirm infection is why this choice is the best fit. The other statements conflict with what’s known: the virus did not originate in cats or birds, it has not remained confined to a small number of states, and diagnosing CIV H3N8 isn’t straightforward without tests.

CIV H3N8 originated in horses and jumped to dogs, with its first recognition in racing greyhounds in the early 2000s. Since then it spread widely, reaching many states across the country. Clinically, canine influenza can resemble other respiratory illnesses, so confirmation often requires specific diagnostic testing, making it relatively difficult to diagnose based on symptoms alone. This combination of equine origin, initial identification in greyhounds around 2003, broad spread, and the need for lab testing to confirm infection is why this choice is the best fit. The other statements conflict with what’s known: the virus did not originate in cats or birds, it has not remained confined to a small number of states, and diagnosing CIV H3N8 isn’t straightforward without tests.