Thursday 24 September 2015

Equine Granulocytic Ehrlichiosis (EGE)

Etiology
Equine Granulocytic Ehrlichiosis (EGE), also called Potomac Horse Fever, is caused by the rickettsial agent Anaplasma phagocytophila. The organism is an obligate intracellular gram-negative bacterium that replicates in the cytoplasmic vacuoles of host cells, particularly granulocytes and monocytes, to form microcolonies called morulae.
Species affected
A. phagocytophila has a wide host range; naturally occurring infections have been recorded in horses, burros, dogs, llamas, and rodents. Humans have also been found to be susceptible to A. phagocytophila infections.
Geographic distribution
A. phagocytophila frequently infects horses in the foothills of northern California. Other states with confirmed clinical infections include Arkansas, Colorado, Connecticut, Florida, Illinois, Minnesota, Pennsylvania, and Washington. Cases have also been confirmed in British Columbia, Great Britain, South America, and Sweden.
Transmission
EGE is a blood-borne infection transmitted by bites from ticks in the family Ixodiae. Infections can also be transmitted by blood transfusions in humans. Mechanical transmission by biting insects has been suggested as a possible means of spread. Incubation period The incubation period is 1-14 days in horses and 7-10 days in humans.
Clinical signs
Severity of signs varies with age of the animal and duration of the illness, becoming more severe over several days. Horses: Less than a year old, fever may be the only clinical sign. One to three year olds develop fever, depression, mild limb edema, and ataxia. Adults exhibit the characteristic signs of fever, partial anorexia, depression, reluctance to move, limb edema, petechiation, and icterus.
Zoonotic potential
Anaplasma phagocytophilum is zoonotic and causes human granulocytic erhlichiosis (HGE). HGE is a generalized disease ranging from mild nonspecific symptoms to severe and possibly fatal hematological disorders. Gastrointestinal signs are common and may be combined with photophobia, conjunctivitis, joint pain, coughing, and confusion.


Prevention and control
Horses that live in areas with Ixodes tick populations should be checked frequently for ticks. If found, ticks should be promptly removed with gloved hands. Human tick bites should be thoroughly disinfected after removal of the tick, and hands should be washed with soap and water. It is important to control tick populations in horse habitats to prevent infection.


Sources
•Center for Food Security and Public Health, Iowa State University Ehrlichiosis fact sheet http://www.cfsph. iastate.edu/Factsheets/pdfs/ehrlichiosis.pdf
• Merck Veterinary Manual http://www.merckvetmanual. com/mvm/index.jsp?cfile=htm/bc/52700.htm
• Franzen P. et al. Death of a horse infected experimentally with Anaplasma phagocytophilum. The Veterinary Record.27 January 2007. http://veterinaryrecord. bvapublications.com.proxy.lib.iastate.edu:2048/cgi/ reprint/160/4/122?view=long&pmid=17259454


Brucellosis in horses

Brucellosis occasionally occurs in horses. The bacteria usually localizes in muscles, tendons and joints, though it is most commonly seen in cases of infected withers in horses.
Drainage from areas infected with this organism contains high numbers of bacteria and is very infectious.
Brucellosis can cause abortion in mares, so transmission is possible for veterinarians handling fetal membranes.
Fistulous withers and poll evil are rare, inflammatory conditions of horses that differ essentially only in their location.
In fistulous withers the sinus is located on the withers and the symptoms are severe inflammation, swelling and pain on manipulation.
Because the exact nature of the infection in many of these cases is known only after obtaining culture results, veterinarians are urged to be cautious and to observe good protective technique when dealing with such cases.
Brucellosis can affect sheep, goats, cattle, pigs, horses, and dogs.
Brucellosis can also affect rats and wild animals including deer, bison, elk, moose, camels, water buffalo, and marine mammals.
People can become infected by eating or drinking (oral) raw milk or unpasteurized milk products that contain the Brucella bacteria.
Direct contact or aerosol exposure to infected animal fluids are additional ways to be infected.
People who work with animals (e.g., livestock producers, veterinarians) may be at higher risk of exposure to Brucella.
Infection in people causes flu-like signs (fever, night sweats, headaches, back pain).
Arthritis (joint pain) and re-occurring fevers may occur with long term infection.
Rarely, cases of brucellosis can involve the nervous system, eyes, or heart.
As the disease progresses one or more openings discharge pus with necrosis affecting the deep seated tissues and spine.
Brucella can survive for months in the environment under optimum conditions but can be destroyed by heat and some disinfectants.
Do not eat or drink raw milk or unpasteurized dairy products.
 Wear protective clothing (gloves, masks) when handling reproductive tissues (assisting delivery of newborn animals). Always wash your hands after touching animals.


Saturday 12 September 2015

Cryptorchidism in horses




Cryptorchidism is the failure of one or both testes to descend into a normal scrotal position from the abdominal cavity after birth.

Horses with one descended testicle are usually fertile, while horses with both undescended testicle are generally sterile. The testes may be retained anywhere from the abdomen to the inguinal canal, the normal passage route into the scrotum.

Three different forms of cryptorchidism are observed in horses: under the skin in the inguinal area, in the inguinal canal and in the abdomen. In bilateral cryptorchids, most of the time both testes are abdominal.
Cryptorchidism may not be apparent at birth, as the testes do not drop from the abdominal space, through the inguinal canal and ring and into the scrotum – where they remain – until after birth. The time it takes before both testes have descended varies from horse to horse but both testes should be in the scrotum by two years of age. In all cases of one undescended testicle, the stallion will still be able to produce normal amounts of testosterone. Usually, the undescended testicle is much smaller than the descended one.

Symptoms and Types

Bilateral cryptorchids/Complete rig

Both testicles remain in the abdomen
Physically appears as a gelding (testes cannot be palpated)
Infertility
Stallion-like behavior

Unilateral cryptorchids

One testicle remains in abdomen
Will still be fertile from the one descended testicle


Causes

Cryptorchidism can be due to hereditary or developmental issues, whereby the testicles fail to drop into the scrotum after birth.

 Treatment

There is only one method of treatment for cryptorchidism in horses — surgical removal of both testes. This is to prevent the trait from being passed on to offspring. In cases where the undescended testicle is low in the abdomen, the castration can be performed on the farm and is generally uncomplicated. If both testicles have been retained and are high in the abdomen, your horse may require more complicated surgery and will be referred to an equine surgical facilit

Interference in horses

 Forging is a common fault in horses working in fast tempo in any of the three gaits. It usually refers to a hind leg hitting (catching) the front leg of the same side. At the walk it is commonly referred to as over reaching, which in most cases involves the hind toe of the shoe striking the front toe of the shoe, hence you can hear it; rarely the horse grabs the heel part of the front shoe at the walk. During forging, the wounds, which some call the "treads", are caused mainly to the lower part of the front leg by the over reaching hind leg. 

“Brushing” refers to contact between opposite (right and left) fore or hind limbs. This most commonly takes place in the lower limb, pastern or fetlock and rarely above the fetlock. Brushing happens as a consequence of a lateral gait deficit, meaning something affecting side-to-side movement of the limbs in flight

“Over-reaching” or “grabbing” is a type of forging in which the toe of the hind foot contacts the lower forelimb on the same side, usually causing a heel bulb wound or catching the heel of the shoe.

“Scalping” refers to contact with the coronet band,  “speedicutting” refers to a strike to the fetlock area, “shin hitting” to the cannon area and “hock hitting’ to the hock region.

Equine hernia


Equine Hernia

A hernia is one of many afflictions that can affect foals during birth. There are two types of hernia that a foal can suffer from, both of which may go by unnoticed until they have grown a bit more. They are caused by some type of defect in the wall of the abdomen, either affecting the umbilical area or the inguinal canal -- a passage in the anterior abdominal wall. This is a congenital defect, one that should be repaired as soon as possible, as it poses a host of health problems for the horse.

Symptoms and Types

Umbilical Hernia
Appears during first six weeks of life
A rotund swelling in the abdominal area
Ring felt underneath the skin

Inguinal Hernia
Enlarged or weakened inguinal ring
Swelling in the inguinal area and, in males, near the scrotum
As time passes, the swelling will become larger

An umbilical hernia occurs when the muscles around the foal's navel fail to close at birth. The hernia may be the result of trauma or it may be hereditary. The umbilical hernia manifests itself as a bulge where the umbilical cord was or is attached. The swelling is tissue that envelops the internal organs, but may also contain part of the intestine.


Causes

Umbilical hernias are due to a congenital birth defect. This defect can cause an abscess to form in the horse's umbilical cord or weaken its abdominal wall, both of which can cause a hernia. Inguinal hernias, on the other hand, are a result of an increased pressure in the abdomen due to a difficult birthing and/or an enlarged inguinal ring -- found at the entrance and the exit of the inguinal canal.


Prevention

Careful treatment of the umbilical area during and after the birth of the foal may help prevent umbilical hernias. Allowing the umbilical cord to break naturally when the foal is born is important. The cord should never be pulled on. If it does not break on its own, the handler or veterinarian will usually find the natural indentation, approximately two inches from the abdomen, grasp the cord on each side of the indentation, and twist it until it breaks apart. The cord usually breaks easily when twisted.

Treatment

Inguinal and umbilical hernias must be treated differently. In addition, inguinal hernias are more urgent than umbilical hernias, as umbilical hernias generally regress after the first few weeks, but inguinal hernias only get larger and more serious.

Surgery is required to treat an inguinal hernia; there is no other method of treatment that has been found to be as effective. Conversely, umbilical hernias are generally left to heal on their own, most going away within the first year. If the umbilical hernia is larger, elastrator rings -- a tool used to dilate an area -- may be used. However, because it may trap the horse's abdominal contents within the abdomen, it should only be attempted by a veterinarian.

procedure is high, but a veterinarian should explain the risks involved.