Although the organism can be isolated from the feces, clinically ill horses are not contagious and can be housed with healthy, non-infected horses. The disease is not considered zoonotic, which means it cannot be passed from horses to humans.

How is Potomac horse fever transmitted?

The transmission of PHF is complex. Horses ingest mayflies and/or caddisflies, which are infected with the rickettsial organism. Ingestion of other hosts involved in the life cycle may also lead to infection.

Can dogs get Potomac horse fever?

The bacterium has also been isolated in cats, dogs, goats, pigs and mice, although in these species, the disease is subclinical. Potomac fever has a seasonal character, ocurring mainly in summer and early autumn, together with the greater proliferation of potential vectors.

Is Potomac horse fever contagious to other horses?

Potomac Horse Fever is not contagious. If more than one horse at the same location contracts the disease, it is because of the environmental conditions that draw the vectors. The disease causes colitis, dehydration and diarrhea.

What is the agent that causes Potomac horse fever?

Potomac horse fever (PHF) is an acute systemic and potentially fatal disease of horses, which is also known as equine monocytic ehrlichiosis. It is caused by Neorickettsia risticii, an obligate intracellular endosymbiotic bacterium of digeneans (Platyhelminthes, Digenea) that parasitize snails and insects1,2.

What is the incubation period for Potomac horse fever?

Because the incubation period is 10-18 days, acutely ill animals often have an elevated PHF IFA titer. Vaccinated animals may have a titer in a similar range. Paired acute and convalescent titers will help sort out response to infection versus a vaccine or previous exposure.

What are signs of Potomac horse fever?

Potomac Horse Fever is a bacterial disease caused by the bacteria Neorickettsia risticii, which causes variable degrees (from mild to very severe) of fever, lethargy, poor appetite, diarrhea, mild colic, and laminitis in horses. It can can also infrequently cause abortion in pregnant mares.

Where is Potomac horse fever found?

PHF has been reported from most states in the United States, five provinces in Canada, South America (Brazil, Uruguay), Europe (France, The Netherlands), and India. Horses of all breeds and ages may be affected, but PHF is not common in younger horses (<1 year).

Should I vaccinate for Potomac horse fever?

A vaccine for Potomac Horse Fever is available. The vaccine does not prevent the disease but can reduce its severity. Horses should be vaccinated prior to the peak seasons of exposure. The clinical signs of Potomac Horse Fever are similar to those of many infectious diseases.

What is laminitis?

Laminitis is a common, extremely painful and frequently recurrent condition in horses, ponies and donkeys. It has significant welfare implications for owners. This condition affects the tissues (laminae) bonding the hoof wall to pedal bone in the hoof.

Article first time published on

What body system does Potomac horse fever affect?

The infection of enterocytes of the small and large intestine results in acute colitis, which is one of the principal clinical signs of PHF. The disease is seen in spring, summer, and early fall and is associated with pastures bordering creeks or rivers.

What causes horse botulism?

Botulism is a rapidly fatal disease with motor paralysis. It is commonly caused by eating food contaminated with the toxin (a type of poison) produced by Clostridium botulinum bacteria. This organism grows rapidly in decomposing animal tissue and sometimes in plant material.

What causes horse salmonella?

In horses, the bacteria are transmitted through contaminated feed or water, or by direct contact with infected individuals or surfaces that have been contaminated with manure from an infected individual. Mice, barnyard chickens, pigeons, and wildlife can be sources of Salmonella.

Is colitis contagious in horses?

Take care to follow appropriate isolation procedures if your horse has infectious colitis, as the contagious bacteria, or virus, can transfer from horse to horse, and even sometimes from horse to human (i.e. Salmonella).

Is Potomac horse fever in Australia?

Potomac horse fever is a seasonal disease due to Ehrlichia risticii and which is geographically restricted to limited areas of North America.

What does strangles do to horses?

Strangles is a highly contagious disease of the equine upper respiratory tract caused by the bacterium Streptococcus equi subspecies equi (S. equi). The bacteria cross mucous membranes in the nose and mouth to infect lymph nodes where they cause abscesses that can eventually rupture.

Is there a cure for Potomac horse fever?

Antibiotic therapy with oxytetracycline is the most common treatment and is usually started as soon as Potomac horse fever is suspected. Other treatments that may be necessary include anti-inflammatory medications such as Banamine®, IV fluids, electrolytes, and specific laminitis treatment/prevention.

What is another name for Potomac horse fever?

Potomac Horse Fever (PHF) is a potentially-fatal febrile illness affecting horses caused by the intracellular bacterium Neorickettsia risticii. PHF is also known as Shasta River Crud and Equine Monocytic Ehrlichiosis.

What does Streptococcus equi cause?

Streptococcus equi causes the disease known as “strangles” in horses. It affects primarily younger horses but may affect older horses that are immunologically naive. S. equi infection is transmitted by direct contact or via fomites such as water troughs, feed bunks, pastures, and stalls.

What is oxytetracycline used for in horses?

Oxytetracycline has been used for treating Potomac fever in horses caused by Neorickettsia risticii, as well as respiratory and soft tissue infections. In newborn horses, oxytetracycline has been administered at high doses for the purpose of correcting angular limb deformities.

Is Potomac horse fever in Canada?

Potomac Horse Fever (PHF) is a seasonal disease, occurring between late spring and early fall in temperate regions of Canada and the United States.

What is equine endotoxemia?

The presence of endotoxins in the blood is referred to as endotoxemia. These toxins are generally due to the presence of certain types of bacteria in the horse’s gut that have breached the gut wall and entered the blood stream. If not treated promptly, endotoxemia can lead to shock, laminitis, and death.

Is there a vaccine for strangles in horses?

There are currently two strangles vaccines available, a killed, “m-protein extract” which is given in the muscle, and a modified live vaccine that’s given intranasally. The intranasal vaccine is more effective and probably safer with regard to risk of purpura.

What does it mean when a horse is floundering?

Laminitis or founder, as it is commonly called, results in the destruction of the sensitive, blood-rich laminae that connect the horse’s hoof to the soft tissue of the foot.

How did secretariat get laminitis?

While Secretariat was fairly healthy during his racing career, he suffered from laminitis after retiring to stud. The cause of his laminitis is unknown, but his health was maintained up until October 4th, 1989 when he was euthanized due to the quick onset of extreme pain.

What is navicular in a horse?

The navicular bone is a small flattened bone, which lies across the back of the coffin joint. It attaches to the pedal bone via a short strong ligament (the impar ligament) and to the pastern joint by ‘suspensory’ ligaments.

What is PHF vaccine for horses?

The currently available commercial vaccine is a killed, adjuvanted product, which is also available combined with rabies vaccine. The current vaccine is labelled as an aid in the prevention of Potomac Horse Fever and is not labeled for prevention of abortion.

What is a high temp for a horse?

“Normal temperature varies in horses, just like in people,” Dreyfuss explained. “An adult’s normal temperature will range from 99 degrees to 101 degrees. Once you get over 101, for most horses, that would be a low-grade fever. For clinical studies, we often define fever as greater than 102 degrees.

How do you test a horse for botulism?

Botulism is diagnosed based on known risk factors and clinical signs. There is no blood test for botulism. As many horses with botulism have difficulty eating, a grain test can easily be performed to help make a diagnosis. Give 8 oz of grain in a pan, and a normal horse should be able to eat it in less than 2 minutes.

Can horses eat alfalfa haylage?

Although baleage, haylage and silage can be fed to horses, it should be done with caution. Baleage, haylage and silage can be very nutrient dense and contains microbes and potential probiotics that can affect the gastrointestinal microbe population.

Is Mouldy haylage bad for horses?

There are moulds or other growth on the haylage. … These coloured moulds can be very dangerous and this should never be fed to horses.