Canine babesiosis – a tick to worry!

In summer months, our pooches need to be safeguarded against tick infections like Babesiosis. Here’s more on this tick transmitted canine disease.
 
Dr Priya Chettri
Dr GM Arpitha
Dr A Sangaran
Babesiosis is an emerging, tick-transmitted canine disease caused by haemoprotozoan
parasite of the genus Babesia. The disease is distributed worldwide and infection is more common in areas where tick infestation is very high and when routine acaricide use is not practiced.
History: Victor Babes was the first person who recognised Babesia in the red blood cells of cattle in 1888. Later in 1893, Kilborne and Smith named it as Babesia, classifying them as protozoans.
Species: There are two Babesia species that cause Babesiosis in dogs – Babesia canis and Babesia gibsoni. While, there are three subtypes of Babesia canis – Babesia canis canis, Babesia canis vogeli and Babesia canis rossi.
 
Risk factors

• Transmitted by the bite of brown dog tick ‘Rhipicephalus sanguineus’: Dogs who spend a lot of time outdoors are at an increased risk for tick bites and for contracting this parasite. This is especially true in the summer months, from May through September, when tick populations are higher.
• Recent dog bite (Babesia gibsoni).
• Blood transfusion from infected donor dog.
• Immunosuppression.
• Splenectomy.
• Transplacental transmission – from the mother dog to the developing foetus through placenta.

How it infects?
Dogs become infected with Babesia sp., when a tick feeds on the blood and releases ‘sporozoites’ into the dog’s bloodstream. These sporozoites invade the red blood cells and multiply leading to the formation of ‘merozoites’ which may be ingested by a new tick during a blood meal. Following ingestion by the tick, Babesia sp., undergoes rapid multiplication, resulting in numerous sporozoites (in the tick salivary glands) that are infective to healthy dogs by the infected tick feeding.
 
Signs and symptoms

• Fever
• Inappetance
• Lethargy
• Pale mucous membranes
•  Vomiting
• Bounding pulses
• Splenomegaly (enlarged spleen)
• Lymphadenopathy(enlarged lymphnode)
• Dark discolouration of the urine (Haemoglobinuria) – often coffee coloured
• Jaundice
• Hemolytic anaemia

Disease is less severe with Babesia canis vogeli than with Babesia gibsoni infection.
How is Babesiosis diagnosed in your pet?
It can be difficult to confirm a diagnosis of Babesiosis. Blood tests may show a decrease in the number of red blood cells and platelets (thrombocytopenia), but this is not specific to Babesia. Blood smears can be examined for the presence of the Babesia organisms. If they are present, the diagnosis can be confirmed, but they may not always show up on a smear (taking blood from a cut on the ear tip or from a toenail can improve the odds of finding the parasites).
The most current and best way to diagnose Babesia canis is polymerase chain reaction (PCR) testing. Blood can also be tested for antibodies to Babesia, though this can sometimes produce misleading results. Specialised testing can check for genetic material from Babesia, and while this is the most sensitive test, it is not widely available and has some limitations as well. Generally, a combination of lab tests along with clinical signs and history are used to make a diagnosis.
The diagnosis can be further complicated by the fact that dogs infected with Babesia may also be infected with other diseases carried by ticks, such as Erlichia, Lyme disease, or Rocky Mountain spotted fever.
 
Which breeds are susceptible?

• The disease can occur in any dog breed
  at any age, but young dogs tend to
  suffer with more serious illness.
• Babesia canis vogeli infections are more prevalent
  in Greyhound breeds.
• Babesia gibsoni infections are more prevalent in American Pit Bull Terriers.

 
What treatment you should give?
If your pet is severely anaemic, he may require a blood transfusion.
Preventing Babesiosis

• The secret of keeping your pet free from Babesia is good tick control.
• Check your dog periodically for ticks (ticks must feed for at least 24-48 hours to spread Babesia). This is especially important in peak tick season or if your dog spends time in the woods or tall grass.
• The best way to remove the ticks is to grasp the tick’s mouth parts with the help of small tweezers and pull them. Try not to crush them.
• Brush or comb your pet regularly.
• Use collars that contain acaricides such as Deltamethrin, Cypermethrin, Flumethrin (Tick Collars) combined with fipronil spray. These are quite effective in repelling ticks. Fipronil spray is more effective than the dropper form.
• Treat your yard and garden with acaricides to control the ticks.
• Blood donor dogs should be screened for Babesia spp. by blood smear, serology and molecular technique such as PCR.

 
(Dr Priya Chettri and Dr Arpitha GM are perusing MVSc in Veterinary Parasitology and Dr A Sangaran, PhD, is a veterinary parasitologist and professor at Madras Veterinary College, Chennai.)