What do ticks transmit in animals? - briefly
Ticks transmit a range of pathogens—including spirochetes such as Borrelia, rickettsiae like Anaplasma and Ehrlichia, and protozoa such as Babesia—causing diseases such as Lyme disease, anaplasmosis, ehrlichiosis, and babesiosis in both domestic and wild animals.
What do ticks transmit in animals? - in detail
Ticks act as vectors for a wide range of infectious agents that affect domestic livestock, companion animals, and wildlife. The principal categories include bacteria, viruses, protozoa, and, in rare cases, helminths.
Bacterial agents most frequently transmitted by ixodid and argasid ticks are:
- Borrelia spp. – cause Lyme disease in dogs and relapsing fever in various mammals; transmitted by Ixodes species.
- Anaplasma phagocytophilum – induces granulocytic anaplasmosis in cattle, horses, and dogs; vectors include Ixodes and Dermacentor ticks.
- Ehrlichia spp. – responsible for canine ehrlichiosis and bovine ehrlichiosis; transmitted primarily by Rhipicephalus and Amblyomma ticks.
- Rickettsia rickettsii – agent of Rocky Mountain spotted fever in dogs and horses; spread by Dermacentor and Rhipicephalus ticks.
- Coxiella burnetii – causes Q fever in ruminants; soft ticks of the genus Ornithodoros can maintain the bacterium.
Viral pathogens carried by ticks include:
- Tick‑borne encephalitis virus (TBEV) – leads to neurological disease in dogs and wildlife; transmitted by Ixodes ricinus and related species across Europe and Asia.
- Crimean‑Congo hemorrhagic fever virus (CCHFV) – severe hemorrhagic syndrome in livestock and wild ungulates; vectors are Hyalomma ticks.
- African swine fever virus (ASFV) – infects domestic pigs and wild boar; soft ticks Ornithodoros moubata serve as long‑term reservoirs.
- Lumpy skin disease virus – occasionally associated with Rhipicephalus species in cattle.
Protozoan parasites transmitted by ticks are:
- Babesia spp. – cause babesiosis in dogs (e.g., Babesia canis) and cattle (Babesia bovis, Babesia bigemina); vectors include Dermacentor, Rhipicephalus, and Haemaphysalis ticks.
- Theileria spp. – responsible for theileriosis in cattle and small ruminants; transmitted by Haemaphysalis and Rhipicephalus ticks.
- Cytauxzoon felis – fatal hemoparasitosis in domestic cats; transmitted by Amblyomma americanum.
Helminth transmission is uncommon but documented for certain filarial worms, such as Dirofilaria immitis in dogs, where Aedes and Culex mosquitoes are primary vectors; ticks may act as mechanical carriers in limited scenarios.
Key aspects of transmission:
- Biological transmission – pathogen undergoes development within the tick before being passed to the next host during feeding.
- Mechanical transmission – pathogen is carried on the mouthparts or in the gut without replication, allowing rapid spread between hosts.
- Transstadial persistence – many agents survive the tick’s molt from larva to nymph to adult, maintaining infectivity across life stages.
- Transovarial passage – some bacteria (e.g., Rickettsia) and viruses (e.g., ASFV) are passed from adult females to offspring, ensuring vertical maintenance of infection.
Geographic distribution aligns with tick species ranges: Ixodes spp. dominate temperate zones of Europe and North America; Rhipicephalus and Amblyoma species prevail in tropical and subtropical regions; Hyalomma ticks occupy arid and semi‑arid habitats of Africa, the Middle East, and Central Asia.
Clinical impact varies by host and pathogen. In cattle, babesiosis and anaplasmosis cause anemia, fever, and reduced productivity; in dogs, Lyme disease manifests as lameness, arthritis, and renal complications; in pigs, African swine fever leads to high mortality and severe economic loss. Early diagnosis and targeted antimicrobial or antiparasitic therapy, combined with tick control measures, remain essential for mitigating disease burden.