This is a disease caused by a range of different protozoan parasite species including so-called large Babesia species (e.g. Babesia canis) and so-called small Babesia species (e.g. Babesia gibsoni). They are transmitted by ticks of several species, around 24-48 hours after tick attachment, and are tropic for red blood cells, causing anaemia but also thrombocytopenia.
Canine babesiosis has a global distribution commonly affecting domestic dogs in Africa, Europe and Asia. Young to middle-aged dogs may be more predisposed, although any dog which does not have immunity is predisposed. Although ticks are the major means of transmission, there have been reports of transmission of some Babesia species by blood transfusions and biting.
It appears that dogs with some immunity may remain carriers for years, and stress or other diseases may induce sudden onset of clinical signs of weakness and collapse.
|Babesiosis type||Drug||Treatment protocol||Possible side Effects|
|Large Babesia species e.g. Babesia canis, Babesia vogelis, Babesia rossi||*Imidocarb diproprionate||6.6 mg/kg IM or SQ (if severe thrombocytopenia) once,
then repeat 2 weeks later
|Uncommon but cholinergic side effects sometimes seen e.g. salivation, lacrimation, diarrhoea, vomiting – can pretreat with atropine if concerned. Usually results in PCR negative results on blood.|
|Small Babesia species e.g. B. gibsoni, B. microti-like (also known as Theileria annae)||Ataquavone plus azithromycin||Seek advice from a specialist
before starting a 10 day treatment course.
|Very difficult to clear infection and treatment not always effective. Some have used doxycycline/ metronidazole/ clindamycin or diminazine/ imidocarb/ clindamycin protocols for B. gibsoni infection.|
|Concurrent Ehrlichia canis infection||Doxycycline||10 mg/kg/d PO||E. canis and B. vogeli are both transmitted by the same tick vector so concurrent ehrlichiosis is treated with doxycycline. Doxycycline may have some activity for small Babesia species and is sometimes used for B. gibsoni infections.|
Bacteria of the genus Bartonella are found in the blood of many wild rodents and larger mammals, such as deer, throughout the world. In these natural hosts, infection with the bacteria does not appear to influence fitness. However, the transfer of these bacteria to domestic animals and humans can result in disease.
Bartonella appear to be transmitted from one animal to another by a range of biting insects, particularly fleas, although ticks have also been implicated. The disease can also pass, to humans at least, by direct inoculation e.g. by scratching or biting by heavily infected animals (thus giving rise to "cat scratch disease" a problem in immuno-compromised humans).
Bartonellosis (infection with Bartonella) is largely an infection of cats where it causes a wide spectrum of problems dependent on the underlying health of the animal, although current work is investigating its association with disease in other companion animal species. It appears that many animals carry Bartonella but remain symptomless. When stressed or immuno-compromised cats may develop fever, anaemia, heart and liver problems and neurological signs.
What is B. burgdorferi s.l.?
These comprise a group of genospecies of spirochaete bacteria (primarily Borrelia burgdorferi sensu stricto, Borrelia afzelii and Borrelia garini) that cause Lyme disease in a small percentage of infected dogs. They are found worldwide including the UK, and are transmitted by the tick Ixodes ricinus, also found in the UK. Recent surveys have found that 2.3% of ticks in the UK were B. burgdorferi s.l. infected. Transmission from the tick to the host occurs about 36 to 48 hours after the tick starts feeding.
Pictured left: I. ricinus is the tick vector for B. burgdorferi s.l., the agent that can cause Lyme disease in dogs
A rash may occur where the tick attached to the dog, but no ‘bullseye’ lesion is seen in the skin as is common in humans infected with B. burgdorferi s.l. In dogs which show clinical signs, these usually develop around 2-5 months after a tick bite and comprise lethargy, fever, polyarthritis and lymphadenopathy. Signs may be worse in young or immunocompromised dogs. Occasionally cardiac, neurological or renal signs are reported.
There are no real characteristic haematology or serum biochemistry changes in B. burgdorferi s.l. infection. A mild thrombocytopenia may be present. In the USA Lyme nephritis is reported, particularly in Labradors and Golden Retrievers, with associated azotaemia and proteinuria, but this is not recognised in the UK.
Not often! PCR is sensitive and specific but the organism needs to be present in the sample submitted for PCR to able to identify it. B. burgdorferi s.l. is not present consistently in the blood of infected dogs, including those with clinical illness so blood samples for PCR are not that useful. Synovial fluid (or synovial membrane) samples from dogs with joint changes will offer increased sensitivity for PCR analysis. If a tick bite has been identified, a skin biopsy taken adjacent to the tick bite can also be submitted for PCR.
Yes. As outlined above, finding B. burgdorferi s.l. by PCR is difficult but infected dogs will usually seroconvert and mount an antibody response. However this occurs in both asymptomatic infected dogs as well as those with clinical Lyme disease, so seropositivity does not equate with disease. The Idexx SNAP4Dx test detects antibodies specific for B. burgdorferi s.l. (most genospecies are believed to be detected although it may not pick up all strains of B. afzelii) and thus can be used as a screening test for Lyme disease in dogs. A positive result may need to be followed up with a quantitative antibody test for B. burgdorferi s.l.
Doxycycline (10 mg/kg SID PO) is the treatment of choice for Lyme disease with 4 weeks of treatment usually recommended with a good response to treatment seen, usually starting within 48 hours. Intensive therapy is required for Lyme nephritis which carries a guarded prognosis.
Effective tick control! Owners should be instructed to avoid tick exposure whenever possible, remove any ticks found on a dog promptly and use a topical ectoparasiticide that is effective against ticks. There is also an inactivated whole cell B. burgdorferi s.l. vaccine available in the UK which can be considered for dogs living in areas known to have a high risk of Lyme disease.
Infected dogs do not pose a direct zoonotic risk to humans but humans can develop Lyme disease following a tick bite with B. burgdorferi s.l. infection. A bullseye rash occurs within a month of the tick bite, moving outward from the bite site over time. Cardiac and neurological signs can develop as well as arthritis.
Lyme disease has not been reported as a clinical entity in cats although evidence of infection with B. burgdorferi s.l. in cats has been reported worldwide, including in the UK.
Ehrlichiosis is caused by tick-transmitted intracellular bacteria that invade monocytes and macrophages (Ehrlichia canis) and in some cases, platelets (Anaplasma, previously Ehrlichia platys. The most common and important species affecting dogs is E. canis. It is transmitted by the tick Rhipicephalus sanguineus, which is well adapted to kennels, houses and cars. It has been reported from the USA, Europe and Africa.
German Shepherds are predisposed to serious disease and may develop a fatal form of infection. Transmission by blood transfusion also occurs.
Clinical signs include intermittent fever, lymphadenopathy, bleeding (petechiation, haematuria, epistaxis, retinal haemorrhage), weight loss, severe eye disease, other signs of immune-mediated disease and bone marrow hypoplasia subsequent with cytopenias.
Thrombocytopenia is marked and platelet function is also impaired. Excessive antibody production leads to high protein levels and may result in hyperviscosity syndrome
|Ehrlichiosis||Drug||Treatment protocol||Side Effects|
|Doxycycline||5-10mg /kg PO
q12-24 for 14-21 days
|Staining of teeth not as much of a problem as for oxytetracycline. Oesophagitis if incomplete swallowing with some formulations in cats|