Babesiosis in Dogs

Babesiosis has an incubation period of about two weeks, so there is often a delay of at least two weeks from infection to the appearance of symptoms. However, symptoms can be very slow to manifest, and cases can be unrecognized for years. Dogs are affected by Babesiosis at rates unrelated to sex, age, and breed. Risk correlates positively with environmental and seasonal exposure to ticks and negatively with proper tick prevention and removal.

The babesiosis piroplasms infect a dog’s red blood cells, causing hemolytic anemia in which red blood cells are destroyed, and excess hemoglobin is released. Excessive hemoglobin can lead to jaundice. An infected dog’s body will fight to produce more red blood cells in order to replace the ones that are lost, but if it cannot produce enough, anemia occurs. The clinical symptoms of babesiosis infection are:

• Lack of energy
• Lack of appetite
• Weight loss
• Fever
• Swollen abdomen
• Unusual urine color
• Unusual stool color
• Yellow or orange-tinged skin
• Pale Gums

Types

• Babesia canis - large piroplasms
• Babesia canis canis - reported in the U.S., Africa, Asia and Australia
• Babesia canis vogeli - most virulent, reported in Africa
• Babesia canis rossi - reported in Europe
• Babesia gibnosi - small piroplasms, reported worldwide
• Babesia conradae - small piroplasms, reported only in California

While the most common cause for babesiosis infection in dogs is transmission through ticks via bite, there are additional causes. Your dog may be infected through direct transmission from an infected animal, also via bite, or through the transfusion of infected blood.

You can aid the veterinarian in diagnosis by bringing your dog in for treatment as soon as you notice symptoms and providing information on the onset as well as any relevant possible causes. Be sure to mention if you have found ticks on your dog recently or lapsed in tick prevention, or if you dog has recently been bitten or received a blood transfusion.

A complete physical examination will be conducted, including a urinalysis and electrolyte panel in order to rule out other possible causes for your dog’s symptoms and assess overall health. However, the most important element for diagnosis is the analysis of your dog’s blood.

In most cases, in addition to a complete blood count, which will measure your dog’s red and white blood cell levels and indicate anemia if present, as well as a chemical blood profile, further analysis of blood samples will be needed. These are a Wright’s stain, which is a histologic stain that allows the veterinarian to differentiate between blood cell types during examination under a microscope in order to identify infection, and immunofluorescent antibody tests, which provoke a reaction to the Babesia organisms and can help differentiate between species and subspecies. Further, a biological sample can be tested through polymerase chain reaction (PCR) in order to draw out DNA and is a more conclusive indicator of species and subspecies of the parasite.

There are treatment methods that have proven effective in suppressing symptoms; however, Babesia infections are often persistent, and even after a recovery, your dog will be considered a permanent latent carrier of the infection. Your dog will be treated with one of several anti-infective agents, depending on the species of Babesia causing the infection. These drugs will be administered intravenously, typically in two doses spaced apart by 14 or so days. Pentamidine isethionate, a drug developed to treat pneumonia, may be used for all species. However, dogs infected with Babesia canis will often be treated by imidocarb disproportionate, which is a urea derivative developed as an antiprotozoal agent specifically for treatment of parasitic infections. Babesia gibsoni and Babesia conradae are the most difficult to treat, and require a combination cocktail of pentamidine isethionate and atovaquone, another pneumonia treatment drug.

The majority of dogs treated respond excellently and will make a rapid clinical recovery. However, there is a possibility of persistent parasitemia in which the infection and its symptoms persist despite treatment. For this reason, you will need to schedule regular follow-up appointments after treatment in order to continue testing for infection. Clinical recovery is defined as three negative polymerase chain reaction tests in a row. Even after recovery, there is a risk of relapse at any time throughout your dog’s life. As with any recovery be sure to closely monitor your dog for the reappearance of symptoms and seek veterinary help as soon as symptoms reappear.

It’s important to know that your dog is a latent carrier of the parasite for life, making her ineligible for blood donation and a risk of transmission to other dogs. Always discourage and prevent dog fights in order to protect other dogs from getting infected. If your home has the presence of multiple dogs, or your dog has recently been in a kennel, notify the kennel and take your other dogs into the veterinarian in order to get tested. In order to prevent further infection, keep your dog on year-round tick prevention and closely examine his skin and fur after he has been in areas that may harbor ticks.