Frequency of Detection and Phylogenetic Analysis of Porcine circovirus 3 (PCV-3) in Healthy Primiparous and Multiparous Sows and Their Mummified Fetuses and Stillborn.

Porcine circovirus 3 (PCV-3) has been suggested as a putative causal agent of swine reproductive disease. A number of different studies have pointed out this association, but there is still a lack of information regarding the normal rates of PCV-3 infection in farms with normal reproductive parameters. The objective of the present study was to assess the frequency of PCV-3 detection in primiparous and multiparous sows and in tissues from their respective fetuses from farms with average reproductive parameters. Sera from 57 primiparous and 64 multiparous sows from 3 different farms were collected at two time points. Brain and lung tissues from 49 mummies and 206 stillborn were collected at farrowing. Samples were tested by PCR, and when positive, quantified by quantitative PCR. Thirty-nine complete genomes were obtained and phylogenetically analyzed. All sera from multiparous sows were negative, while 19/57 (33.3%) primiparous sows were PCV-3 PCR positive. From the 255 tested fetuses, 86 (33.7%) had at least one tissue positive to PCV-3. The frequency of detection in fetuses from primiparous sows (73/91, 80.2%) was significantly higher than those from multiparous ones (13/164, 7.9%). It can be concluded that PCV-3 is able to cause intrauterine infections in absence of overt reproductive disorders.

Efficacy of Simparica Trio™, a novel chewable tablet containing sarolaner, moxidectin and pyrantel, against induced hookworm infections in dogs.

BACKGROUND: Ancylostomatids ('hookworms') are among the most important zoonotic nematode parasites infecting dogs worldwide. Ancylostoma caninum and Uncinaria stenocephala are two of the most common hookworm species that infect dogs. Both immature and adult stages of hookworms are voracious blood feeders and can cause death in young dogs before infection can be detected by routine fecal examination. Hence, treatment of both immature and adult stages of hookworms will decrease the risk of important clinical disease in the dog as well as the environmental contamination caused by egg-laying adults, which should reduce the risk of infection for both dogs and humans. The studies presented here were conducted to evaluate the efficacy of a novel, oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™), against induced larval (L4), immature adult (L5) and adult A. caninum, and adult U. stenocephala infections in dogs. METHODS: Eight negative-controlled, masked, randomized laboratory studies were conducted. Two separate studies were conducted against each of the target parasites and stages. Sixteen or 18 purpose bred dogs, 8 or 9 in each of the two treatment groups, were included in each study. Dogs experimentally infected with the target parasite were dosed once on Day 0 with either placebo tablets or Simparica Trio™ tablets to provide minimum dosages of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5.0 mg/kg pyrantel (as pamoate salt). Timing of dosing relative to parasite inoculation allowed for efficacy to be evaluated primarily against the target parasite stage. Worm counts were conducted 7 or 8 days after treatments during necropsy. Efficacy was based on the number of worms recovered at necropsy compared to placebo control. RESULTS: Based on geometric mean worm counts, efficacy of Simparica Trio™ was ≥ 98.4% against L4 larval stage of A. caninum, ≥ 99.8% against immature adult (L5) A. caninum, and 100% against adult A. caninum and adult U. stenocephala. CONCLUSIONS: These studies confirm the efficacy of a single oral dose of a novel, chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against L4 larval and immature adult (L5) A. caninum, and adult A. caninum and U. stenocephala infections in dogs.

Compartmentalized Immune Response in Leishmaniasis: Changing Patterns throughout the Disease.

Visceral leishmaniasis (VL) is characterized by loss of T-cell responsiveness and absence of Leishmania-specific IFN-γ production by peripheral blood mononuclear cells. However, the expressions of IFN-γ and TNF-α are up-regulated in the tissues and plasma of VL patients. There is a paucity of information regarding the cytokine profile expressed by different target tissues in the same individual and the changes it undergoes throughout the course of infection. In this work we evaluated IFN-γ, TNF-α, IL-10, and TGF-ß mRNA expression using real-time RT-PCR in 5 target tissues at 6 months and 16 months post-infection (PI) in a canine experimental model which mimics many aspects of human VL. The spleen and liver of Leishmania infantum experimentally-infected dogs elicited a pro- and anti- inflammatory response and high parasite density at 6 and 16 months PI. The popliteal lymph node, however, showed an up-regulation of IFN-γ cytokin at commencement of the study and was at the chronic phase when the IL-10 and TGF-ß expression appeared. In spite of skin parasite invasion, local cytokine response was absent at 6 months PI. Parasite growth and onset of clinical disease both correlated with dermal up-regulation of all the studied cytokines. Our VL model suggests that central target organs, such as the spleen and liver, present a mixed cytokine immune response early on infection. In contrast, an anti-inflammatory/regulatory immune response in peripheral tissues is activated in the later chronic-patent stages of the disease.

Characterization of circulating lymphocyte subpopulations in canine leishmaniasis throughout treatment with antimonials and allopurinol.

Canine leishmaniasis (CL) is a systemic parasitic disease with a wide variability of response to specific therapy: the majority of patients apparently improve with treatment, some of them respond but later relapse, and few of them do not respond at all. It has been demonstrated that the immune response plays a key role in the development and outcome of Leishmania infection in the dog and in the response to the treatment, although this response is not well understood. Some authors have suggested that ill dogs show a reduction in the percentage of circulating CD4+ lymphocytes and in the CD4+/CD8+ ratio, both of which normalize after treatment and clinical recovery. The present paper discusses the variation of the different lymphocyte subpopulations (CD3, CD4, CD8, CD21) of peripheral blood mononuclear cells (PBMC) in 28 dogs diagnosed with CL and submitted to conventional treatment with meglumine antimoniate (Glucantime) for 1 month and with allopurinol (Zyloric) for 1 year, in order to evaluate the usefulness of these parameters as indicators of the immunological condition of the ill animals and of the prognosis of their evolution during the treatment. It is concluded that circulating lymphocyte subpopulations are similar in dogs with leishmaniasis and in healthy dogs and that there is no correlation between the clinical status or response to therapy and the values of the counts of the different lymphocyte subpopulations. Therefore, the percentage of different lymphocyte subpopulations cannot be used as a parameter to predict the evolution of an individual patient in a clinical context.