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Borrelia burgdorferi

Blood-feeding ectoparasites such as ticks, fleas, sand flies and mosquitoes can transmit many dangerous pathogens – e.g. bacteria, protozoa, viruses or helminths – to dogs and cats. They may lead to a variety of serious infections, grouped and labeled by their vectors: tick-borne diseases, flea-borne diseases, sand fly-borne diseases and mosquito-borne diseases, to name a few.

Different geographical regions have their own risks of infection. Nevertheless, seven major companion vector-borne diseases (CVBD) seem to have a worldwide impact: anaplasmosis, babesiosis, ehrlichiosis, heartworm disease, leishmaniosis, Lyme borreliosis and subcutaneous dirofilariosis.

These major companion vector-borne diseases are summarised in the table below.

Major canine diseases transmitted by vectors


Anaplasma phagocytophilum

Ixodes spp. ticks

US: Deer tick (I. scapularis) and Western black-legged tick (I. pacificus)
Europe: Castor Bean tick (I. ricinus)

Infestation of white blood cells (neutrophils)

Signs: fever, lethargy, weight loss, diarrhoea, vomiting, seldom bleedings and lameness

US: states in the north-eastern, mid-Atlantic, upper north-central regions, and north-western California

Europe: northern and central countries like Germany, Czech Republic, Austria, Scandinavia, Scotland and many regions in eastern Europe including Russia

Anaplasma platysBrown Dog tick (Rhipicephalus sanguineus)Can infest platelets, thereby causing fever, depression and a bleeding tendencyCommon in tropical and temperate regions



Babesia spp.

Ticks of several species;

In Europe esp. the Ornate Cow tick (Dermacentor reticulatus) and the Brown Dog tick (Rhipicephalus sanguineus)

Infestation of red blood cells

Signs: fever, lethargy, anorexia, anemia, red urine, splenomegaly, jaundice

Global Distribution

Common in Africa, Europe, Asia, America, Oceania


Ehrlichia canisBrown Dog tick (Rhipicephalus sanguineus)

Infestation of white blood cells (monocytes)

Signs: fever, depression, lymphadenopathy, anorexia, weight loss, hair loss, lethargy, bleedings, eye signs

Widespread in tropical and temperate areas

Reported from the USA, Europe (Mediterranean region) and Africa

Heartworm Disease

Dirofilaria immitisMosquitoes (AedesCulex, Anopheles spp.)

Infestation of heart and lung 

Signs: weakness, lethargy and apathy, weight loss, dyspnea, coughing

Common in Southern Europe, US, Canada, Australia as well as South-eastern and Eastern Asia, including Japan

Europe: prevalent in Portugal, Spain, Southern France, Italy, Greece and other peri-Mediterranean countries

Lyme Borreliosis (Lyme Disease)

Borrelia spp.Ixodes spp. ticks, like Castor Bean tick (I. ricinus) in Europe; Deer tick (I. scapularis) and Western black-legged tick (I. pacificus) in the U.S.

Infestation of organs and connective tissues  

Signs: lameness, depression, fever, renal disease, cardiac disease, hepatic disease 

US: states in the north-eastern, mid-Atlantic, upper north-central regions, and north-western California 

Europe: Germany, Switzerland, Czech Republic, Slovakia, Austria, Scandinavia, and many regions in Eastern Europe including Russia 

Occurrence also confirmed in Asia (China, Japan) and probably Australia 



Leishmania infantumSand flies (Phlebotomus spp.), esp. P. perniciosus in the Mediterranean Region and Lutzomyia longipalpis in South America

Infestation of white blood cells in the bone marrow

Signs: fever, anorexia, enlarged lymph nodes, wasting, lethargy, alopecia, skin lesions, eye signs, seldom liver and/or kidney failure, polyarthritis, diarrhoea

In more than 100 countries, from warm temperate through subtropical to tropical climates

Extremely common in the Mediterranean area and South America; also found in Africa and Asia

Subcutaneous Dirofilariosis

Dirofilaria repensMosquitoes (AedesCulex, Anopheles spp.)

Infestation of the skin

Signs: small and painless nodules

Common in Southern Europe, Middle East, Asia and Africa

Europe: prevalent in Italy, Southern France, Portugal, Spain, Greece and Eastern Europe

Ectoparasite control is an important measure to reduce the risk of CVBDs. Especially ectoparasiticides with not only acaricidal/insecticidal but additional repellent efficacy affect the arthropod-host interaction – including attachment and blood feeding – and thus reduce the risk of infection.

Prevention of tick attachment and flea, sand fly or mosquito bites must be an established tool of disease prophylaxis in pets living in vector endemic areas, or travelling with their owners to such regions. Dog and cat owners should be made aware of the risks and the need for protection by their veterinarians.


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The CVBD World Forum is a working group of leading international experts with the mission to enhance knowledge and communication on companion animal vector-borne diseases for the improvement of animal, human, and environmental health.

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