EQUINE | Equine Disease Quarterly
susceptible horses that is clinically manifest by fever,
colic of variable severity and profuse diarrhea. All
ages and breeds of horses are at risk of developing the
disease. Infections in pregnant mares can give rise to
abortion immediately following infection or months
after the resolution of clinical signs.
Equine neorickettsiosis has been recorded in Kentucky
for a significant number of years. Incidence of the
disease can be very variable with increased case
numbers frequently seen in years with high rainfalls in
the spring followed by above average temperatures in
late spring/early summer.
In 2018, the disease was first confirmed in Kentucky on
June 1st. Over the period extending through the week
of 25th August, 26 cases were diagnosed. This figure is
probably under-representative of the true incidence of
the disease. The case definition for EN was based on
presence of characteristic clinical signs together with a
positive polymerase chain reaction (PCR) test result for
the causal bacterium.
A breakdown of the total number of cases revealed
30
that the disease was confirmed in nine counties, the
majority in central Kentucky (Figure 1). Affected horses
ranged from one to 17 years of age.
The preponderance of cases (20) was seen in mares.
Although the majority of cases were in Thoroughbreds
(18), the disease was recorded in six other breeds. Of
the 26 reported cases in the state, six died and the
remainder survived.
To minimize losses from EN, horsemen were
encouraged to review the environment in which they
kept their horses and to consult with their veterinarian
on strategies that might be used to mitigate disease
risk. Recommendation was also given to minimize
the opportunity for horses to ingest aquatic insects by
turning off lighting in and around barns and other areas
at nighttime.
CONTACT:
E.S. Rusty Ford
[email protected]
Office of the Kentucky State Veterinarian
Frankfort, KY
• Equine Health Update •