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OBJECTIVE To describe the clinical disease, diagnostic findings, medical management, and outcome in dogs with alveolar echinococcosis (AE). ANIMALS 4 dogs with naturally occurring AE. PROCEDURES Medical records were retrospectively reviewed from 2020 to 2022 to identify dogs diagnosed with AE. Signalment, case history, clinical signs, imaging and pathological laboratory findings, treatment, and clinical outcome were reported. RESULTS All dogs developed systemic clinical illness and weight loss. Abdominal ultrasonography revealed multifocal to coalescent cystic masses of variable size distributed throughout the liver in all cases. Evaluation of aspirated hepatic cyst contents included membranous parasite structures and calcareous corpuscles. Echinococcus multilocularis was confirmed via PCR from hepatic cyst fluid in 3 of 4 cases. Treatment included systemic benzimidazole and praziquantel administration, 1 or more instances of ultrasound-guided cyst drainage in all cases, with ethanol ablation (percutaneous aspiration-injection-reaspiration) in 2 cases, and surgical resection in 1 case. Two of 4 dogs were euthanized within 5 months of diagnosis. One of these dogs was necropsied and had nearly complete obliteration of the hepatic parenchyma by multilocular cystic masses. One dog is still alive, and 1 dog has been lost to follow-up. CLINICAL RELEVANCE This series of cases highlighted the diagnostic findings and therapeutic intervention in 4 dogs with AE. This was the first report of medical management incorporating the percutaneous aspiration-injection-reaspiration method used in humans. Reports of canine AE are rare in the US, so this series serves to help raise awareness of hepatic AE in the northwestern US.

We made 2 Z-based in situ hybridization (ISH) probes for the detection of rabbit hemorrhagic disease virus 2 (RHDV2; Lagovirus GI.2) nucleic acid in formalin-fixed, paraffin-embedded tissues from European rabbits ( Oryctolagus cuniculus) that had died during an outbreak of RHD in Washington, USA. One probe system was made for detection of negative-sense RNA (i.e., the replicative intermediate RNA for the virus), and the other probe system was constructed for detection of genomic and mRNA of the virus (viral mRNA). Tissue sets were tested separately, and the viral mRNA probe system highlighted much broader tissue distribution than that of the replicative intermediate RNA probe system. The latter was limited to liver, lung, kidney, spleen, myocardium, and occasional endothelial staining, whereas signal for the viral mRNA was seen in many more tissues. The difference in distribution suggests that innate phagocytic activity of various cell types may cause overestimation of viral replication sites when utilizing ISH of single-stranded, positive-sense viruses.

Formalin-fixed, paraffin-embedded tissues from European rabbits ( Oryctolagus cuniculus) that succumbed to rabbit hemorrhagic disease virus 2 (RHDV2; Lagovirus GI.2) during the 2019 outbreak in Washington, USA, were utilized for in situ hybridization via RNAscope (ACDBio). This detection method was both sensitive and specific, with no staining in tissues from RHDV- ( Lagovirus GI.1) and RHDV2-negative rabbits, and only slight background staining of RHDV-positive rabbits; RHDV2-positive tissues had bright-red cytoplasmic staining. Although much of the viral mRNA detection was consistent with previously described antigen detection via immunohistochemistry of the liver, lungs, and spleen, there was also significant glomerular staining in the kidneys, and endothelial staining within blood vessels of almost all organs. We validated the RNAscope technique for detection of RHDV2 mRNA in formalin-fixed, paraffin-embedded tissues, with increased sensitivity from previous techniques, and identified additional affected cell types that may contribute to the understanding of pathogenesis.

This case raises the potential association between cervical arterial dissection and VZV vasculopathy. We advise angiographic imaging of neck vessels when VZV vasculopathy is suspected.

Theileria parva kills over one million cattle annually in sub-Saharan Africa. Parasite genetic complexity, cellular response immunodominance, and bovine MHC diversity have precluded traditional vaccine development. One potential solution is gene gun (GG) immunization, which enables simultaneous administration of one or more DNA-encoded antigens. Although promising in murine, porcine, and human vaccination trials, bovine GG immunization studies are limited. We utilized the model T. parva antigen, polymorphic immunodominant molecule (PIM) to test bovine GG immunization. GG immunization using a mammalian codon optimized PIM sequence elicited significant anti-PIM antibody and cell-mediated responses in 7/8 steers, but there was no difference between immunized and control animals following T. parva challenge. The results suggest immunization with PIM, as delivered here, is insufficient to protect cattle from T. parva. Nonetheless, the robust immune responses elicited against this model antigen suggest GG immunization is a promising vaccine platform for T. parva and other bovine pathogens.

Rabbit hemorrhagic disease virus 2 (RHDV2) causes an often-fatal disease of rabbits that has resulted in outbreaks in rabbitries in Europe, Africa, Australia, and Asia. RHD has historically been characterized as a foreign animal disease in the United States. In July 2019, RHDV2 was detected in rabbits on Orcas Island along the northwestern coast of Washington (WA) State following reports of deaths in multiple feral and domestic rabbits. We document and highlight here the unique clinical presentation and gross and histologic lesions observed in this recent WA outbreak. Affected rabbits died without premonitory signs or displayed hyporexia and/or lethargy for ≤1 d prior to death. The most consistent pathologic finding was random, multifocal hepatocellular necrosis, often with concurrent multifocal-to-diffuse splenic necrosis. The lack of significant clinical signs in conjunction with the random distribution of hepatic necrosis in the WA outbreak contrasts with previous reports of RHDV2 disease progression.

Giardia cysts are commonly encountered in fecal examinations of dogs; intestinal infections can be asymptomatic or cause diarrhea but have not been previously associated with urticaria. A five-month old dalmatian puppy presented with a one-week history of cutaneous urticaria and pruritis. Wheals were most prominent on the head, abdomen, and inguinal region. A fecal flotation was performed to rule out internal parasites as a cause of hypersensitivity. Fecal float yielded many Giardia cysts, and treatment for giardiasis with fenbendazole was initiated. Urticaria improved drastically within a day after treatment initiation and completely resolved by the completion of the treatment regimen. No Giardia cysts were detected on the follow up fecal flotation three days later, and fecal Giardia antigen testing was negative at this time. No additional changes in management, housing, food, or environment were noted and the puppy has remained without additional clinical signs for three months following initial presentation.

Recombinant herpesvirus vaccine vectors offer distinct advantages in next-generation vaccine development, primarily due to the ability to establish persistent infections to provide sustainable antigen responses in the host. Recombinant bovine herpesvirus-4 (BoHV-4) has been previously shown to elicit protective immunity in model laboratory animal species against a variety of pathogens. For the first time, we describe the induction of antigen-specific immune responses to two delivered antigens in the host species after intranasal nebulization of recombinant BoHV-4 expressing the chimeric peptide containing the bovine viral diarrhea virus (BVDV) glycoprotein E2 and the bovine herpesvirus 1 (BoHV-1) glycoprotein D (BoHV-4-A-CMV-IgK-gE2gD-TM). In this study, four cattle were immunized via intranasal nebulization with the recombinant BoHV-4 construct. Two of the cattle were previously infected with wild-type BoHV-4, and both developed detectable serologic responses to BVDV and BoHV-1. All four immunized cattle developed detectable viral neutralizing antibody responses to BVDV, and one steer developed a transient viral neutralizing response to BoHV-1. Approximately one year after immunization, immunosuppressive doses of the glucocorticoid dexamethasone were administered intravenously to all four cattle. Within two weeks of immunosuppression, all animals developed viral neutralizing antibody responses to BoHV-1, and all animals maintained BVDV viral neutralizing capacity. Overall, nebulization of BoHV-4-A-CMV-IgK-gE2gD-TM persistently infects cattle, is capable of eliciting antigen-specific immunity following immunization, including in the presence of pre-existing BoHV-4 immunity, and recrudescence of the virus boosts the immune response to BoHV-4-vectored antigens. These results indicate that BoHV-4 is a viable and attractive vaccine delivery platform for use in cattle.

Tick-borne pathogens that cause persistent infection are of major concern to the livestock industry because of transmission risk from persistently infected animals and the potential economic losses they pose. The recent reemergence of Theileria equi in the United States prompted a widespread national survey resulting in identification of limited distribution of equine piroplasmosis (EP) in the U.S. horse population. This program identified Babesia caballi -seropositive horses using rhoptry-associated protein 1 (RAP-1)–competitive enzyme-linked immunosorbent assay (cELISA), despite B. caballi being considered nonendemic on the U.S. mainland. The purpose of the present study was to evaluate the suitability of RAP-1–cELISA as a single serological test to determine the infection status of B. caballi in U.S. horses. Immunoblotting indicated that sera from U.S. horses reacted with B. caballi lysate and purified B. caballi RAP-1 protein. Antibody reactivity to B. caballi lysate was exclusively directed against a single ∼50-kDa band corresponding to a native B. caballi RAP-1 protein. In contrast, sera from experimentally and naturally infected horses from regions where B. caballi is endemic bound multiple proteins ranging from 30 to 50 kDa. Dilutions of sera from U.S. horses positive by cELISA revealed low levels of antibodies, while sera from horses experimentally infected with B. caballi and from areas where B. caballi is endemic had comparatively high antibody levels. Finally, blood transfer from seropositive U.S. horses into naive horses demonstrated no evidence of B. caballi transmission, confirming that antibody reactivity in cELISA-positive U.S. horses was not consistent with infection. Therefore, we conclude that a combination of cELISA and immunoblotting is required for the accurate serodiagnosis of B. caballi .