EQUINE | Equine Disease Update
EQUINE | Equine Disease Update
ciated with evidence of respiratory disease . Equine infectious anemia was recorded in Canada and the USA . Nine cases were diagnosed on three premises in Saskatchewan Province , Canada . Two cases were confirmed on each of two premises in New York and Oklahoma , USA . France recorded that equine piroplasmosis was endemic in the country . In the USA , Theileria equi infection was confirmed in Quarter horse racehorses engaged in non-sanctioned racing in Tennessee ( seventeen cases ) and Wyoming / Utah ( 21 cases ). Germany reported nine cases of CEM on eight premises , the majority in stallions and horses of the Icelandic breed . The USA reported cases / outbreaks of salmonellosis during the third quarter . Two cases involved serogroup B Salmonella spp ., 10 with serogroup C1 spp . and two with serogroup D1 spp . Outbreaks of clostridial enteritis due to Clostridium perfringens Type A , genotyped as β-2 toxin positive , were recorded by the USA , two in Kentucky and two in Minnesota .
France and Germany confirmed limited outbreaks of rotavirus infection in foals . One case of infection with Lawsonia intracellularis was diagnosed in a foal in Kentucky , USA . Single cases of rabies were recorded in Oklahoma and Florida , USA . The USA reported 49 cases of Eastern equine encephalomyelitis during the period under review . The greatest numbers of cases were confirmed in Florida , Wisconsin , and South Carolina . The USA confirmed a total of 88 cases of West Nile encephalitis involving seventeen states .
The vast majority were in non-vaccinated horses or those with incomplete vaccination histories . Rhodococcus related disease was considered endemic in the USA . Notwithstanding the fact that it is very difficult to estimate the prevalence of this infection , some 40 cases were confirmed during the third quarter . Japan confirmed eight cases of Getah virus infection on one premises , the majority having incomplete vaccination histories . Infected horses displayed typical clinical signs of the disease . The USA reported three cases of Equine Monocytic Ehrlichiosis in Maryland and West Virginia . Isolated cases of Ehrlichiosis were also confirmed in Germany and Switzerland .
Observation , Science , and Equine Lameness Diagnosis
A significant number of pain-related gait abnormalities in horses are evident only when the horse is ridden , and are not apparent when the horse is handwalked or lunged . Even when these horses are ridden , the lameness may not be overt . While there have been many recent technical advancements in the objective assessment of gait , these are generally of limited value for detection of bilaterally symmetrical alterations in gait that result in reduced performance such as generalized stiffness , lack of willingness to work , alteration in quality of movements such as lack of hindlimb engagement and impulsion , and alteration in the rider ’ s feel of the contact via the reins and bit to the horse ’ s mouth . A rider often assumes that these problems are attributable to thoracolumbar region pain , because the problems are only manifest when the horse is ridden .
When observed on the lunge , such horses may lean into the circle — often more on one rein than the other — and show exaggerated contractions of the epaxial muscles . However , studies have shown that experimentally induced forelimb or hindlimb lameness may reduce range of motion of the thoracolumbosacral vertebral column . Radiographic examination may reveal impinging spinous processes , and this finding often results in an erroneous conclusion implicating thoracolumbar pain as the primary problem . We have demonstrated that by using diagnostic analgesia to abolish overt or subclinical lameness , the rider often appreciates an increased range of motion of the horse ’ s back . To investigate these clinical ob-
26 • Equine Health Update •