infection | Horse Racing Free Tips

Horses Often Adept At Hiding Dental Pain

Though most horse owners and caretakers will investigate a horse's mouth for pain if he's refusing to eat his feed entirely, equines often offer other clues that their mouths may hurt, reports EQUUS magazine.

Scientists from the University of Helsinki surveyed the owners of 47 horses that had cheek teeth surgically removed because of root infections. Tooth root infections can be caused by several things, but most of these removals were the result of dental fractures.

[Story Continues Below]

The survey asked 23 questions of these owners regarding horse behavior. Respondents noted that the behaviors that were eliminated after the surgical tooth extraction included dropping hay, eating slowly and adjusting hay in the mouth while chewing.

Before surgery, horses with dental pain often avoided the bit, raising their heads or getting “behind” the bit to avoid contact. Painful horses also behaved more antisocially toward people and horses. All of these behaviors dissipated when the painful tooth was removed.

Dr. Jaana Pehkonen, lead researcher, said that avoiding the bit was the most common indicator that something was amiss. She notes that this may be because this behavior is easiest to notice.

In half the study horses, tooth infections were not discovered until a routine dental exam took place, indicating that many owners miss behaviors that can be linked to dental pain. Only six of the 47 horses had obvious signs of tooth issues like external swellings or sinus drainage. Nearly all the owners said that their horses were more comfortable after the teeth were removed.

Pehkonen concluded that some equine behaviors, like self-mutilation, aggressive behavior or withdrawnness aren't regarded as pain behaviors by horse owners. However, once the pain is removed and the horse returns to acting “normal,” it's easier to see that the behaviors indicated discomfort. Pehkonen recommends horses have annual dental exams so that any problems can be identified.

Study: Horses And Chronic Hepatitis

The most common cause of acute viral hepatitis in horses is serum hepatitis, also called Theiler's disease, which causes liver atrophy and necrosis. Worldwide outbreaks have been reported in conjunction with the use of equine-derived blood products, including tetanus antitoxin, botulinum antitoxin, equine plasma, Streptococcus equi antiserum and pregnant mare's serum.

Between 1.4 and 18 percent of horses receiving an equine-derived product have reported a sudden or severe hepatitis infection. A novel parvovirus dubbed an equine parvovirus-hepatitis (EqPVH) has been identified as the cause of Thieler's disease in horse serum samples the United States, Canada, New Zealand, Italy, and Germany, indicating that the parvovirus occurs worldwide.

[Story Continues Below]

Interestingly, EqPV-H has also been found in horses with Thieler's disease that did not receive biological equine serums.

Dr. Birthe Reinecke, postdoctoral fellow with the Institute of Experimental Virology, and a team of scientists created a study to determine if chronic EqPV-H infection is a possibility and if cross-species infection can occur. The team used 124 German horses for a five-year study as well as 318 human serum samples: 147 samples were from humans with no horse contact and 171 samples were from humans who had contact with horses for their work. They also used 494 donkey serum samples from Germany, Italy and Bulgaria, and archived samples from zebras.

Most horses used in the study were EqPV-H negative, but some has virus in their blood. The team determined that horses can be infected with the disease for up to five years, even if they show no clinical signs of the disease. About 1 percent of donkeys were positive for EqPV-H (5 of the 494 animals), meaning that the disease can also affect donkeys.

Read the full study here.

Joint Care: Provide Support After Wounds, Infection

Viscous and transparent, synovial fluid acts as a biological lubricant within musculoskeletal mechanisms. Penetrating wounds to joints and tendon sheaths cause most infections, though pathogens carried in the bloodstream, as with foals diagnosed with joint ill, have been implicated, as has contamination at the time of intraarticular injection or surgery. Veterinarians refer to infection that sets up in any structure containing synovial fluid, namely joints, tendons, and bursas, as synovial sepsis.

Prompt diagnosis and aggressive treatment minimize damage to septic structures and often prevent career- and life-threatening consequences. To determine if infection is present, bacterial isolation through culture is the best diagnostic tool, yet low sensitivity and long laboratory turnaround time often preclude a definite diagnosis in the face of emergency situations and treatment decisions, which may include joint irrigation and surgery. Because of these limitations, researchers have sought alternative ways to quickly identify the presence of infection.

[Story Continues Below]

Austrian researchers recently evaluated the presence of specific biomarkers, called antimicrobial proteins, in synovial fluid as a way to confirm infection.^* These proteins are activated by the immune system in response to a pathogenic challenge, so their existence in the fluid indicates sepsis. According to the researchers, “using enzyme activity as a biomarker of synovial sepsis enables the development of a point-of-care diagnostic test, which would allow veterinarians to perform, analyze, and act on test results stall-side, in a matter of minutes.”

In the study, researchers collected synovial fluid samples from three groups of horses: healthy controls, horses with aseptic synovitis (inflammation without infection), and horses with septic synovitis. Enzyme activity assays were compared with standard synovial fluid parameters and broad-range bacterial DNA extraction.

The researchers found enzyme activities were significantly different between septic synovial samples and aseptic and control samples, leading them to believe that measurement of enzyme activities would allow for reliable, rapid diagnosis of synovial sepsis and immediate therapeutic interventions.

Joint health depends largely on conscientious management of exercise, including frequency and intensity of athletic bouts, and the provision of high-quality nutritional supplements formulated specifically for joint support. While synovial sepsis typically develops from injuries that compromise the joint capsule, it can occur following routine intraarticular injection of hyaluronic acid and corticosteroids, though the incidence of infection is uncommon.^° The prophylactic use of joint supplements in high-performance horses and prospects can delay the need for joint injections, thus postponing any risk associated with invasive procedures.

^*Haralambus, R., A. Florczyk, E. Sigl, S. Gultekin, C. Vogl, S. Brandt, M. Schierer, C. Gamerith, and F. Jenner. 2021. Detection of synovial sepsis in horses using enzymes as biomarker. Equine Veterinary Journal. In press.

^°Steel, C.M., R.R. Pannirselvam, and G.A. Anderson. 2013. Risk of septic arthritis after intra-articular medication: A study of 16,624 injections in Thoroughbred racehorses. Australian Veterinary Journal 91(7):268-273.

Horse Owner Dilemma: To Bandage Or Not To Bandage?

It seems like horses injure themselves often but even with lots of practice, determining how to best care for their leg wounds can be difficult. That includes deciding whether a wound needs a bandage, or if a covering will impede the healing process.

According to EQUUS magazine, there are three main considerations when trying to decide whether to reach for the bandaging supplies:

Mobility: A wound that pulls open with every step a horse takes will heal more rapidly if it's wrapped. Though often more difficult to keep in place if over a joint like the knee or hock, a bandage is beneficial.

Depth: If the wound is so deep the underlying structures can be seen, infection is a real risk. Bandaging the wound is the best bet until granulation tissue can fill in the gap.

Proximity to the ground: A wound near the hoof on a pastern or coronet band is more likely to get dirt, manure and debris in and on it than one located higher up the leg. Additionally, if it's a hind leg injury on a gelding or stallion, there's a risk urine will splash on the cut and irritate the tissues. These wounds benefit from bandaging.

Wounds that can remain open do well when covered at least twice daily in a thick ointment to keep bacteria, dirt and insects out.