respiratory disease | Horse Racing Free Tips

Strangles: A Worldwide Problem That Researchers Say Needs Better Monitoring

One of the more common equine respiratory diseases is strangles, a contagious bacterial infection caused by Streptococcus equi. Most horses recover from strangles with no complications, though the disease can make some horses very sick. Ten percent of horses remain carriers once they are infected, meaning they don't show clinical signs, but they can spread the disease.

Because of the potential significant health and welfare consequences – and the economic costs associated with the disease – finding additional information about the strangles is crucial.

Dr. Catriona Mitchell and colleagues from 18 countries used DNA sequencing techniques to analyze 670 Streptococcus equi isolates from 19 countries. The researchers found different variants of the disease. Strangles in the United Kingdom, the United Arab Emirates and Argentina are closely linked. The research team determined that the movement of horses and global trade help spread the disease.

The team suggests that labs utilize an online surveillance platform called Pathogenwatch to monitor the emergence and spread of new strains of strangles. This will assist with interventions and policy-making decisions.

The authors suggest that strangles be recognized by the World Organization for Animal Health (OIE) as an internationally important disease. They also suggest that identifying horses that are infected with strangles before or immediately after travel would limit the movement of the disease.

Read the full article here.

Study: Heaves Can Wreak Havoc On More Than Just Lungs

Horses with uncontrolled respiratory disease have more organs at risk than simply their lungs, new Canadian research shows. Drs. Serena Ceriotti, Michela Bullone, Mathilde Leclere, Francesco Ferrucci and Jean-Pierre Lavoie have discovered that horses with uncontrolled respiratory disease are at risk of having pulmonary arterial changes that could lead to heart failure.

Horses that suffer from severe equine asthma have inflamed airways; they also cough and have difficulty breathing. The researchers hypothesized that this condition, which is triggered by dust and mold in a horse's hay and environment, can put horses at risk of pulmonary hypertension. Pulmonary hypertension occurs when the walls of the pulmonary arteries thicken and increase the horse's blood pressure.

For the study, the research team obtained multiple post-mortem lung samples from 18 horses: six that were in heaves episodes when they died; six that were in remission from heaves from being kept in a dust-free environment; and six that had no heaves and served as controls.

The researchers measured the thickness of the arteries and found that horses with uncontrolled asthma had thicker arterial walls than other horses in the study.

Why the artery walls thicken when a horse has breathing trouble is unknown, but it is hypothesized that the low oxygen content and inflammation may increase the amount of smooth muscle in the artery walls, which makes it more difficult for blood to move out of the lungs. Eventually, this condition could lead to an enlargement and failure of the right ventricle of the heart.

The final part of the team's study focused on potential treatments for pulmonary hypertension in horses: they used 11 asthmatic horses divided into two groups that were treated for a full year with two different treatment protocols. One group had reduced dust exposure, primarily through the feeding of hay alternatives. The second group went on a corticosteroid for the first six months, the had dust control measures added in. Both treatments led to a reversal in arterial wall thickness, but changes in the second group were not seen until the dust control measures were taken.

They scientists determined that the thickening of arterial walls in horses with heaves can be reversed, but environmental changes must be made; the administration of corticosteroids, while helpful, must be made in conjunction with changes in management.

Read the full study here.

Stall-Side Test For Equine Disease May Assist With COVID-19 Detection

Scientists have discovered a way to use a cell phone's camera to detect respiratory diseases like equine influenza in horses; that same technology could help identify COVID-19 in humans. These easily spread diseases can cause large death tolls, as well as economic loss and disruption of daily life.

One complication to slowing the spread of diseases like these are the is the lack of widely available testing that can offer speedy and accurate results, reports The Horse. This means that communities are unable to make informed recommendations regarding quarantines that can help control the spread of the disease.

Early diagnosis of disease, whether in horses or humans, is key to controlling the spread of disease, notes Dr. Brian Cunningham, an electrical and computer engineering professor at the University of Illinois at Urbana-Champaign. If obtaining results takes days, whether because of a backlog of samples or lab closures because of holidays, the virus has already spread before a positive result is even given. Adding to the potential delay in diagnosis and implementation of control strategies is that some affected patients may have more than one disease.

Cunningham has developed a testing technique for a variety of equine respiratory pathogens, including Streptococcus equi, EHV-1 and EHV-4, and equine influenza. The test uses nasal swabs to detect viral RNA, which is converted to DNA and then amplified in compartments on a silicon chip. Each compartment on the chip can be used to test for a different virus. The chemical reaction it produces replicates billions of copies of the original viral nucleic acid sequence. Fluorescent markers bind to the DNA during amplification, which can be seen on smartphone cameras as green light.

The entire test takes about 30 minutes and can be done stall side, eliminating the need to send samples to a lab and wait, possibly days, for results. With modification, the test could also be used to detect contagious human respiratory viruses like COVID-19.