72025 North Ave.

Armada, Michigan, 48005

Phone: (586) 784-9111


Emergency: (586) 784-9111

FAX: (586) 522-4232


Krause Veterinary Clinic

Location Hours

Closed between 12pm-1pm 

Monday 8:00am — 6:00pm
Tuesday 8:00am — 5:00pm
Wednesday   8:00am — 6:00pm
Thursday 8:00am — 5:00pm
Friday 8:00am — 5:00pm
Saturday 8:00am — 3:00pm
Sunday Closed



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Potomac Horse Fever

Commonly known as Ditch fever, Shasta River crud  and equine ehrlichial colitis

Potomac Horse Fever (PHF) is a gastrointestinal disease that may produce mild colic, fever and diarrhea in horses, as well as abortion in pregnant mares. An organism called Neorickettsia risticii is the cause of the disease.

When and where does it occur?

The disease is usually seen in late spring, summer and early fall. PHF has been reported in many areas of the U.S. and Canada. As the name implies, the organism was first thought to be found primarily in the Northeastern U.S., but has since been isolated from clinical cases in California, Illinois, Indiana, Kentucky, Maryland, Michigan, New York, New Jersey, Ohio, Oregon, Pennsylvania, Texas and Virginia.

Are there carriers of the organism that causes PHF?

The organism has been found in freshwater snails and isolated from flukes (“flatworms”)  released from the snails. It has also been found in caddisflies, mayflies, damselflies,  dragonflies and stoneflies.

What is the primary mode of transmission of PHF?

Transmission is thought to be by the horse ingesting insects found in water, feeds or grass that carry the infectious stage of the organism.


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What are some of the potential clinical signs of PHF?

Clinical signs of PHF are mild depression and poor appetite, as well as fever. Within 24-48 hours, a moderate to severe diarrhea develops in more than half of infected horses, often accompanied by signs of mild colic. Laminitis (founder) may be a complicating factor of PHF. Abortion may occur in pregnant mares one to two months following recovery from PHF infection.

» Clinical signs: diarrhea, colic, depression, anorexia

» Time of year: late spring through early fall

» Definitive identification of the organism, using PCR to test blood and feces

» Examining paired serum samples for a rise in antibody titer

How do you treat PHF?

» Early detection of illness and implementing treatment may help reduce complications

» IV antibiotics

» IV fluids

» Anti-inflammatories

» Treatment and preventive measures for laminitis

Is Potomac Horse Fever contagious?

Clinically ill horses are not contagious and can be housed with susceptible horses.