Anaplasmosis: Get ahead of the game

From the December issue of Drovers Cow/Calf.

Potentially lethal, easily spreadable and economically devastating, anaplasmosis can pack a powerful punch to beef producers who are not up to speed on the blood-infesting organism. The parasite itself is called Anaplasma marginale, and it operates by sinking its teeth into red blood cells and morphing into a peppercorn figure once inside. Once spotted by the immune system, the red blood cell is labeled an antigen and kicked to the curb, leaving the victim extremely anemic.

When it comes to the transmission of anaplasmosis, there are two main offenders, says University of Tennessee Extension veterinarian Lew Strickland.

First up is the ixodid species tick, aka “the American dog tick,” aka “the wood tick.” These vectors spread anaplasmosis through blood transmission as pests and make their way from cow to cow to cow.

“Because of the high transmission rate from ticks, anaplasmosis is going to be more prevalent during tick season — depending on your location, hitting in the summer and carrying through the fall,” Strickland says. “Biting flies are also potential carriers of the disease.”

The second offender is referred to by Strickland as a two-legged tick, aka “humans.” Research has shown it takes less than 0.005 mLs of blood from an infected cow to transmit anaplasmosis to a non-infected cow. To put that in perspective, one drop converts into 0.05 mLs, making it unsurprising that research has also shown a 60 percent probability in transmission of anaplasmosis when a needle is shared on multiple animals.

“Because it takes so little blood to spread anaplasmosis and there is a chance of altering the makeup of medications with a disinfectant, I recommend changing needles in between each animal,” he says. “Yes, I realize that is a hassle, but think about what a pregnant heifer is worth right now. If you lose her, is it worth it to you?”

Disinfecting equipment is another check mark producers need to be putting on their to-do lists, Strickland stresses, saying that the transmission of blood from things such as castration equipment, dehorners or eartaggers can spread anaplasmosis.

“A simple way of cleaning equipment is to mix ¾ cup of bleach with a gallon of water,” he says. “Then soak instruments in the solution for one minute to properly disinfect.”  

Recognize the signs

Strickland says once an animal becomes infected it can take three to five weeks before signs start to develop. All ages of cattle are susceptible, but younger cattle typically have a milder infection or even no signs of infection, while older animals become more severely affected.

Symptoms will include a high fever, lethargy, dark yellow urine, crusty nose and the whites of their eyes turning yellow, he says.  If a cow displays symptoms of anaplasmosis, it can be confirmed by a veterinarian with blood testing.

Other signs are weakness, decrease in milk production and appetite, aggressive behavior and white or yellow coloration of gums. Pregnant females may abort calves and bulls can have temporary infertility. However, calves born to an infected cow can be healthy. If an animal survives, its performance in general will be lower and it will become a lifelong carrier of the disease.

While anaplasmosis is treatable through the use of oxytetracycline antibiotics, it will take doses several days in a row. Also, if an animal is severely anemic, it may require a blood transfusion to prevent the animal from dying. Strickland highly recommends working with your veterinarian on diagnosing and treating severe cases.

Think prevention

According to Strickland, producers can get a jump on anaplasmosis by feeding Aureomycin (chlortetracycline) in minerals and feed during times of the year prior to typical outbreaks.

“Wherever you are located, start feeding it before tick and fly season begins,” he says. “If you know they start hitting heavy in April, then get your prevention program into action in March.” 

Strickland also encourages producers to get their herds screened to pull out any carriers in the herd.

“A cow may not show any signs of anaplasmosis but still be spreading it through the herd,” he says. “A simple blood test pulled by your veterinarian from the tail can have lab results within a week.”

USDA has approved the production and distribution of an anaplasmosis vaccine through Louisiana State University. However, it can only be obtained by a state veterinarian for use in Arkansas, California, Florida, Georgia, Idaho, Indiana, Illinois, Iowa, Kansas, Kentucky, Louisiana, Maryland, Mississippi, Missouri, Nevada, North Dakota, Ohio, Oklahoma, Oregon, Tennessee, Texas, Virginia, West Virginia, Wisconsin and Puerto Rico.

No one is immune

As history has shown, once anaplasmosis infects an area it is typically there for good. But just because a region hasn’t had an outbreak doesn’t mean producers can relax preventive precautions.

“Historically, anaplasmosis has been prevalent in west Tennessee and not so much in the east side of the state. Producers in the eastern area were not paying as close of attention, which resulted in one operation losing 20 animals to an anaplasmosis outbreak,” Strickland says. “Just because it isn’t there, don’t think it isn’t going to show up on your doorstep.

“Be watching, pay attention and put good preventative management into practice.”