prevention of tick infestation using acaricides, and vaccination. (Vogt et. al., 2019) As Lyme borreliosis is transmitted via the tick bite, prevention of tick attachment and feeding must be seen as the first obligation of any tick- control agent. (Vogt et. al., 2019) The primary limitation of many acaricides is that they might not offer complete protection if they target only the adult stage of ticks. Another potential drawback with acaricides is that most require monthly reapplication/administration, which could reduce owner compliance and thus product efficacy. Vaccination offers an alternative approach to prevention of disease, but efficacy is unclear with efficacies ranging from 50% to 100%. (Alhassan, et. al., 2019) Borrelia vaccines for dogs are worldwide administered to dogs in endemic areas. However, it is not possible to distinguish a vaccinated dog from a naturally exposed one using serological methods. The reported efficacies of Borrelia burgdorferi vaccines in dogs are highly variable, ranging from 50% to 100%. Vaccinated dogs are less likely to develop clinical signs after exposure to B. burgdorferi compared to unvaccinated dogs. (Alhassan, et. al., 2019) Clinical symptoms Rickettsia rickettsii is an obligately intracellular coccobacillus that infects endothelial cells. Because it is endotheliotropic, vasculitis is a major clinical manifestation of infection. (Kidd et. al.,2020) RMSF is generally an acute, febrile illness. Clinical signs are consistent with a vasculitis and include fever, vomiting, ocular signs (retinal hemorrhage, uveitis, episcleral injection), lymphadenomegaly, splenomegaly, peripheral edema, cutaneous hyperemia and necrosis, polyarthritis, and neurologic signs. Signs may be complicated by prior or simultaneous infection with other tick-borne pathogens. (Backus et. al., 2023) Infected dogs can develop fever and thrombocytopenia, similar to other tick-borne diseases of dogs, such as canine ehrlichiosis and anaplasmosis. Progressive disease manifestations include petechiae, lethargy, limb or facial edema, and death. (Coile, 2023) Necrosis of the extremities (acryl gangrene) or disseminated intravascular coagulation can develop in severely affected dogs. (Foley et. al., 2024) Thrombocytopenia is common. Leukopenia develops during the early stages of infection and, in untreated cases, is followed by progressive leukocytosis. Serum biochemical abnormalities may include hypoproteinemia, hypoalbuminemia, azotemia, hyponatremia, hypocalcemia, and increased liver enzyme activities. (Foley et. al., 2024) Differential diagnoses (Backus et. al., 2023) A) Infection with other tick-borne agents such as Anaplasma phagocytophilum, Ehrlichia spp., Bartonella spp., Babesia spp., and Borrelia burgdorferi A. Leptospirosis and other causes of vasculitis and thrombocytopenia B. Other causes of severe systemic decompensation and vasculitis such as sepsis and systemic inflammatory response syndrome (SIRS)Very early in infection, PCR of circulating blood may be positive, although many severely affected animals become PCR negative as the bacteria become
Despite effective treatment in the majority of early cured Lyme disease cases, relapse may occur after antibiotic administration is discontinued. The causative agent B. burgdorferi can establish a persistent infection in the host. Patients who recover after antibiotic therapy are susceptible to reinfection. (Milkovičová, 2023) The efficacy of antibiotic treatment used in dogs showing signs of acute arthritis should be rapid (1–3 days) if the clinical signs are a consequence of LB. If it is necessary, then analgesic treatment (e.g., gabapentin for neuropathic pain) is started. Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) is less preferred to avoid the necessary “wash-out” period and to reduce the risk of gastrointestinal ulceration if subsequent glucocorticosteroid therapy is indicated for suspected immune-mediated polyarthropathy in unresponsive dogs. If relapse occurs before or after finishing antibiotic treatment, secondary diagnoses should include other infectious diseases, immune-mediated diseases, soft tissue trauma (e.g., ligament or meniscal tears), septic arthritis, or degenerative joint disease. (Littman The most commonly used methods for prevention of B. burgdorferi infection in dogs include tick avoidance, Rocky Mountain spotted fever (RMSF is called Brazilian spotted fever or spotted fever rickettsiosis outside the United States.) et. al., 2018) Prevention Rocky Mountain spotted fever (RMSF) is a severe and potentially deadly tick-borne disease in people and dogs. The causative agent, Rickettsia rickettsii , is transmitted by several species of ticks, including Dermacentor andersoni, Rhipicephalus sanguineus , and Amblyomma americanum . (Foley, 2020) In the USA, Dermacentor variabi lis (the American dog tick) and D. andersoni (the Rocky Mountain wood tick) have been considered the primary vectors for R. rickettsii . (Foley et. al., 2024) Rhipicephalus sanguineus (brown dog tick), unlike other vectors of R. rickettsii , is dependent on dogs to complete its life cycle. (Zazueta et. al., 2021) R. sanguineus is the primary vector in some focal areas of Arizona, particularly on native American tribal lands. (Foley et. al., 2024) A feature common to many outbreaks has been the presence of large populations of stray and free-ranging dogs heavily infested with ticks. In these settings, canine populations can sustain and perpetuate massive numbers of brown dog ticks ( Rhipicephalus sanguineus sensu lato), which serve as efficient vectors of R. rickettsii bacteria. (Zazueta et. al., 2021) Dogs are the preferred host for brown dog ticks and serve as a reservoir of infection for people. Even if a dog is not seropositive against a rickettsial organism and ticks are not seen, we can infer brown dog tick exposure and therefore possible risk of RMSF based on canine serology surveys for other brown dog tick-transmitted pathogens. (Coile, 2023) The pathogen is acquired by larval and nymph stages of ticks while feeding on infected vertebrate hosts and is also passed from female ticks to progeny through transovarial transmission. RMSF transmission through blood transfusion has been documented in a human case and should be considered when selecting canine blood donors. (Foley et. al., 2024) When a tick attaches itself to a dog or human, the bacteria R. rickettsii is injected into the bloodstream. However, the tick needs to be attached for 5 to 20 hours before the bacterium enters the bloodstream, so quick removal is important. (Kidd, 2020)
resident in endothelium. Indirect fluorescent antibody titer (IFA) and ELISA are available
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