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Animal Science
Info Series: AS - B 288
The University of Tennessee
Extension
Anaplasmosis is a disease of cattle, sheep and goats resulting in anemia and sometimes deathespecially in adult cattle. This disease is seen worldwide and is a common disease in thesouthern United States. One of several microorganisms named Anaplasma causes this disease,which is spread from carrier cows to susceptible cows by insects such as ticks or horse flies,surgical instruments such as those, used for castration and dehorning or hypodermic needles. Affected cattle become very anemic and will lose weight, have labored breathing, developconstipation and become more aggressive. Treatment with tetracycline antibiotics is usuallysuccessful in early cases. The Tennessee State Veterinarians’s Office reports an increase in theincidence in 2004. Anaplasmosis is due to one of several microorganisms with Anaplasma marginale being the mostcommon in cattle. The Anaplasma organism is found attached to red blood cells in the bloodstream of affected animals. Carrier cattle have the organism in the blood stream and are capableof spreading the disease but do not show signs of anaplasmosis. Carrier cattle result when calvesare infected before birth or during the first year of life. These animals plus older cattle that haverecovered from the disease can remain carriers for years serving as a source of infection for therest of the herd. These recovered adult cattle generally do not show signs of Anaplasmosis in thefuture.
The Anaplasma organism is spread when blood from is transferred from a carrier animal to asusceptible animal. Often, transmission occurs when insects such as Dermacentor ticks, horseflies, horn flies or others take blood on their mouthparts from an infected animal and then feedon another animal transferring blood. Face flies and other nonbiting insects do not spread thisdisease. Castration instruments, dehorning equipment, and hypodermic needles, which are notdisinfected between animals, also can result in the spread of the disease. The Anaplasmaorganism multiples in the blood stream and attaches to red blood cells, causing the body todestroy the infected red blood cells. Eventually, red blood cells are destroyed faster than thebody can make them and a low red blood cell count results in two to six weeks. Clinical signs of Anaplasmosis vary with the age of the infected animal. Infected calves, less thanone year of age, generally do not show signs of the disease or will show only mild signs. However,they often become carriers. Cattle, one to three years of age, do show clinical signs, which may besevere. Cattle, more than three years of age, show severe signs of disease and up to 50% may dieif not treated. Typical clinical signs include weight loss, rapid, labored breathing, weakness, constipation andincreased aggression. Cattle may require two to three months to completely recover though the mostsevere stage of the disease lasts about four days. Other diseases may show clinical signs similar toAnaplasmosis. Diagnosis is based on clinical signs, microscopic examination of blood to identifythe Anaplasma organism, and other blood tests to identify antibodies in carrier animals.
Affected animals need to be moved and handled carefully for treatment. These animals are easilystressed and can die of oxygen starvation when moved and restrained. The treatment of choice isa single injection of long-acting tetracycline antibiotic. A number of brand names are available fromanimal health product stores. This treatment may save the animals life and shorten the recoveryperiod, but the recovered animals will likely remain carriers. Prevention of Anaplasmosis is based on identifying carrier animals, eliminating the carrier statein these animals, reducing the spread of the disease to other animals and reducing the severity ofclinical signs in newly infected animals. Carrier animals can be identified by blood tests of allanimals best done during the winter when new carriers are less likely to occur. These animals canbe culled or treated to eliminate the carrier state. The carrier state can be eliminated with the use of long-acting Tetracycline antibiotics every threedays for four treatments. The spread of the disease can be reduced by use of various methods ofinsect control and by sanitizing needles and instruments between individual animals. Reducing thefrequency and severity of clinical signs requires monthly injections of tetracycline antibiotics or thefeeding of tetracycline antibiotics during the fly season. Vaccines have been available in the past anda new one is being developed. However, it appears that there is currently no vaccine available toTennessee producers.
Remember to consult your local veterinarian for help in disease diagnosis and treatment. All animalhealth products should be administered according to Tennessee Quality Assurance guidelines.

Source: http://animalscience.ag.utk.edu/beef/pdf/AnaplasmosisInCattle-ASB288-FMH-WWG.pdf