Tick fever is one of the most common and dangerous diseases that occur in dogs in Hong Kong. As a pet owner, you should know more about the symptoms of tick fever and what we can do to prevent our furry friends from getting infected.
What is tick fever and how does the dog get infected (Babesia)?
Babesia canis, Babesia gibsoni and Ehrlichia Canis are the 3 most common tick-borne infections in Hong Kong. Today we would focus on the comparison of Babesia Canis and Babesia Gibsoni. Babesia infection is an important tick-borne disease caused by several species of Babesia organisms. In most cases, the parasites are mainly transmitted through tick bites. Once the organisms enter the dog’s body, they invade and attack its red blood cells, often leading to anaemia.
However, Babesia Gibsoni can be transmitted directly from one animal to another, for example, an infected dog with an oral lesion or abrasions bites another dog, and infected pregnant females can also transmit Babesia to their unborn pups. Dogs can also inadvertently become infected through a transfusion of contaminated blood. Due to the potential for transmission through blood, all red blood cell concentrates (pRBCs) provided by Wellness Veterinary Hospital are tested for multiple infectious diseases, including Babesia spp, to ensure the safety of blood recipients.
What is the difference between Babesia Canis and Babesia Gibsoni?
Babesia Canis and Babesia Gibsoni differ morphologically based on their size on the blood smear. Babesia Canis – Large (4–5 μm long) form of Babesia. Pyriform in shape, pointed at one end and round at the other. In a single RBC, multiple infections can be found, that is, more than one organism up to 16. Babesia gibsoni – Small (1.5–2.5 μm) form of Babesia. Lacking the usual pyriform shapes, the trophozoites are annular or oval; Signet ring shapes may appear.
Polymerase chain reaction (PCR)-based diagnostic assays have increased the detection rate of very low-level parasitemia, as they can detect Babesia DNA. The PCR test can be used for the identification and differentiation of the various Babesia species. This test is now one of the recommended laboratory tests for the diagnosis of babesiosis because it is more sensitive and equally specific compared to the evaluation of peripheral smears.
What are the symptoms?
In general, symptoms are less severe with Babesia Canis infection than with Babesia Gibsoni, even if they have similar clinical signs. Dogs infected with Babesia can present with a wide variety of symptoms ranging in severity from sudden collapse with systemic shock, to a hemolytic crisis (the body attacks and destroys red blood cells called hemolysis), to a subtle, slowly progressing infection with no signs.
Dogs also commonly present with the acute, severe form of babesia, which is characterized by abnormal dark orange urine, fever, weakness, pale mucous membranes, depression, loss of appetite, swollen lymph nodes, and an enlarged spleen. Blood and urine tests may reveal anaemia, thrombocytopenia (low platelets), hypoalbuminemia (low albumin, a protein in the blood), and bilirubinuria (a pigment from the breakdown of red blood cells found in the urine).
How is babesiosis treated?
As mentioned above, Babesia organisms would destroy red blood cells in the body, leading to life-threatening anaemia. Therefore, treatment generally consists of three components:
- Blood transfusions to treat severe anaemia.
- Antiprotozoal drugs help kill the parasite.
- Provide supportive care to treat complications or side effects of illness, such as oxygen therapy to treat breathing problems or anti-nausea medications to help prevent vomiting.
Please note that Babesia Gibson is considered more challenging to treat than Babesia Canis. Recommended treatment protocols for Babesia Gibsoni include the combination of atovaquone (a quinone antimicrobial drug) and azithromycin (an antibiotic).
What happens if it is not treated and how to prevent it?
As mentioned, Babesia organisms destroy red blood cells in the body, causing anaemia. It can be fatal if left untreated for a long time. Therefore, prevention is very important. The risk of infection can be reduced for dogs by controlling ticks with a topical or oral miticide, it is best to consult your vet on the best possible way to keep your dog away from tick-borne infections. But no prevention is 100% protective, so it’s a good idea to inspect your dog for ticks regularly by brushing him in the opposite direction of fur growth. If ticks are found, you should go to the vet as soon as possible.