Long-term follow-up of a single dose of fluralaner in nine dogs with demodicosis.

BACKGROUND: Long-term follow-up of oral fluralaner for canine demodicosis has not been demonstrated. OBJECTIVES: A multicentre prospective open trial for the efficacy of oral fluralaner for the long-term (>12 month) management of canine demodicosis. ANIMALS: Client-owned dogs diagnosed with demodicosis at nine veterinary clinics. METHODS AND MATERIALS: A single fluralaner dose was administered orally. Although shampoo was allowed to treat secondary pyoderma, no other medication or shampoo was allowed, except for medication for possible underlying disorders. Each dog underwent a thorough parasitological and dermatological assessment monthly for three months and was followed up for >12 months. RESULTS: Twenty-six dogs were enrolled. Their ages ranged from three months to 16 years. The cases were nine juvenile and 17 adult onsets; and 18 generalised and eight localised forms. Fluralaner administration resulted in 100% eradication of mites and complete resolution of all skin lesions at three months. Seventeen dogs were excluded from the one year follow-up evaluation as they had required a second dose of isoxazoline or died from causes unrelated to the fluralaner treatment. In the remaining nine cases, no relapse was observed in any of the dogs (six adult and three juvenile onsets; six generalised and three localised forms). Four dogs were monitored for over one year, one dog for over two years, and four dogs for three years. CONCLUSIONS AND CLINICAL RELEVANCE: The results indicated that a single dose of fluralaner could effectively deliver a long-term cure when combined with managing underling conditions.

Change in the responsiveness of interferon-stimulated genes during early pregnancy in cows with Borna virus-1 infection.

BACKGROUND: Borna disease virus is a neurotropic pathogen and infects the central nervous system. This virus infected a variety of animal species including cows. The most of cows infected with Borna disease virus 1 (BoDV-1) exhibit subclinical infection without any neurological symptoms throughout their lifetime. We previously reported on the low conception rates in-seropositive cows. Interferon-τ (IFN-τ) plays an important role in stable fertilization, and is produced from the fetal side following embryo growth at 15-40 days of pregnancy. IFN-τ induces the expression of interferon-stimulated gene (ISG) 15 and Mx2 in peripheral blood mononuclear cells (PBMCs). To understand the embryo growth and maternal reaction during early pregnancy in cows with BoDV-1 infection, we aimed to assess the gene expression of ISG15 and Mx2 from PBMCs in BoDV-1-seropositive cows. RESULTS: None of the cows showed any clinical and neurological symptoms. Among the cows that conceived, the expressions of the ISG15 and Mx2 genes were greater in the BoDV-1-seropositive cows than in the BoDV-1-seronegative cows; the difference was significant between the cows that conceived and those that did not (P < 0.05). CONCLUSIONS: The expression of ISG15 and Mx2 genes during early pregnancy significantly increased in the BoDV-1-seropositive cows and may be important for the maintenance of stable pregnancy in BoDV-1-infected cows. In contrast, the gene expression levels of ISG15 and Mx2 did not significantly increase during early pregnancy in BoDV-1-seronegative cows. Thus, BoDV-1 infection may lead to instability in the maintenance of early pregnancy by interfering with INF-τ production.

Characterization of a variant CD4 molecule in Japanese Black cattle.

Monoclonal antibodies (mAbs) that recognize cluster of differentiation (CD) molecules on lymphocytes are useful tools for the study of different lymphocyte subsets in flow cytometry (FCM) analysis. CD4 is a glycoprotein found on the surfaces of helper T cells, monocytes, macrophages, and dendritic cells. In this study, we describe Japanese Black (JB) calves in a farm whose peripheral blood mononuclear cells (PBMCs) did not react with a CD4-specific mAb. To identify calves with PBMCs with low mAb reactivity, PBMCs from 21 JB calves (1-12 months of age) bred at the same farm were examined using two different bovine CD4 mAbs (clones #CC8 and #CACT138A). FCM analysis indicated that the calves fell into two groups based on reactivity against the two mAbs, i.e., double-positive (DP) calves, whose PBMCs were recognized by both mAbs clones, and single-positive (SP) calves, whose PBMCs were only recognized by #CACT138A. PBMCs from seven calves were not recognized by #CC8, although they had normal reactivity with another mAb, #CACT138A. Sequencing analysis of the CD4 gene in these calves revealed four nucleotide substitutions (G918 T, A930C, G970A, and G1074A) in the coding region in the SP group when compared to the DP group. Three of the four mutations were associated with amino acid substitution (Q306H, K310 N, and A324 T). The substitution at A324 T was located in the D4 domain of CD4 gene. Homology modeling based on the amino acid sequences revealed that the surface structure of this part of the molecule was significantly different between the SP and the DP groups. Therefore, the epitope recognized by the #CC8 CD4 mAb was altered in calves with this genetic mutation, and this led to the low reactivity of the PBMCs from calves in the SP group aginst the #CC8 mAb. In conclusion, this is the first study to identify CD4 variants in JB cattle. We confirmed that the variants did not affect lymphocyte functions, such as mitogen stimulation or lipopolysaccharide-induced cytokine gene expression.