Novel Rickettsia Species Infecting Dogs, United States.

In 2018 and 2019, spotted fever was suspected in 3 dogs in 3 US states. The dogs had fever and hematological abnormalities; blood samples were Rickettsia seroreactive. Identical Rickettsia DNA sequences were amplified from the samples.

T Cells Exacerbate Lyme Borreliosis in TLR2-Deficient Mice.

Infection of humans with the spirochete, , causes Lyme borreliosis and can lead to clinical manifestations such as arthritis, carditis, and neurological conditions. Experimental infection of mice recapitulates many of these symptoms and serves as a model system for the investigation of disease pathogenesis and immunity. Innate immunity is known to drive the development of Lyme arthritis and carditis, but the mechanisms driving this response remain unclear.

Infection of Interleukin 17 Receptor A-Deficient C3H Mice with Borrelia burgdorferi Does Not Affect Their Development of Lyme Arthritis and Carditis.

Recently, a number of studies have reported the presence of interleukin 17 (IL-17) in patients with Lyme disease, and several murine studies have suggested a role for this cytokine in the development of Lyme arthritis. However, the role of IL-17 has not been studied using the experimental Lyme borreliosis model of infection of C3H mice with Borrelia burgdorferi. In the current study, we investigated the role of IL-17 in the development of experimental Lyme borreliosis by infecting C3H mice devoid of the common IL-17 receptor A subunit (IL-17RA) and thus deficient in most IL-17 signaling.

The role of eicosanoids in experimental Lyme arthritis.

Experimental Lyme arthritis is an inflammatory arthritis caused by infection of mice with the spirochete, Borrelia burgdorferi. It recapitulates many of the disease parameters seen in human patients with Lyme arthritis, and thus serves as a model system for the investigation of disease pathogenesis. While much progress has been made in defining components of the immune response to Borrelia infection, an overall understanding of the host response leading to arthritis resistance or susceptibility remains elusive.

Systemic mycosis in three dogs from nonendemic regions.

Three dogs were examined for clinical signs ultimately attributed to systemic fungal infections. One dog was evaluated for chronic, ulcerated dermal lesions and lymphadenomegaly; one dog was examined for acute onset of unilateral blepharospasm; and one dog had diarrhea and hematochezia. Two of the dogs were diagnosed with blastomycosis (one with disseminated disease and the other with the disease localized to the left eye).