Spillover of highly pathogenic avian influenza H5N1 virus to dairy cattle.

Highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b virus has caused the death of millions of domestic birds and thousands of wild birds in the U.S. since January, 20221-4 Throughout this outbreak, spillovers to mammals have been frequently documented5-12. We report spillover of HPAI H5N1 virus in dairy cattle herds across several states in the U.S. The affected cows displayed clinical signs encompassing decreased feed intake, altered fecal consistency, respiratory distress, and decreased milk production with abnormal milk. Infectious virus and viral RNA were consistently detected in milk from affected cows. Viral distribution in tissues via immunohistochemistry and in situ hybridization revealed a distinct tropism of the virus for the epithelial cells lining the alveoli of the mammary gland in cows. Whole viral genome sequences recovered from dairy cows, birds, domestic cats, and a raccoon from affected farms indicated multidirectional interspecies transmissions. Epidemiologic and genomic data revealed efficient cow-to-cow transmission after apparently healthy cows from an affected farm were transported to a premise in a different state. These results demonstrate the transmission of HPAI H5N1 clade 2.3.4.4b virus at a non-traditional interface underscoring the ability of the virus to cross species barriers.

A one-health review on brucellosis in the United States.

Brucellosis is a highly infectious zoonotic disease of global significance due to its adverse impact on public health, economics, and trade. Despite being one of the most prevalent zoonoses worldwide, attention given to global brucellosis control and prevention has been inadequate. Brucella species of greatest one-health relevance in the US include those infecting dogs (Brucella canis), swine (Brucella suis), and cattle and domestic bison (Brucella abortus). Although not endemic in the US, Brucella melitensis warrants awareness as it poses a risk to international travelers. While brucellosis has been eradicated from domestic livestock in the US, its detection in US companion animals (B canis) and US wildlife reservoirs (B suis and B abortus) and enzootic presence internationally pose a threat to human and animal health, warranting its spotlight on the one-health stage. The challenges of B canis diagnosis in humans and dogs is addressed in more detail in the companion Currents in One Health by Guarino et al, AJVR, April 2023. Human consumption of unpasteurized dairy products and occupational exposure of laboratory diagnosticians, veterinarians, and animal care providers are responsible for human exposures reported to the US CDC. Diagnosis and treatment of brucellosis is challenging due to the limitations of diagnostic assays and the tendency of Brucella spp to produce nonspecific, insidious clinical signs and evade antimicrobial therapy, making prevention essential. This review will focus on zoonotic considerations for Brucella spp found within the US along with their epidemiology, pathophysiology, clinical presentation, treatment, and control strategies.

Antibody response over time correlated with treatment outcome in 30 dogs naturally infected with Brucella canis (2017-2022).

OBJECTIVE: Brucella canis is a zoonotic bacterial pathogen of dogs that is notoriously difficult to diagnose and treat. Humans can become infected with B canis when an infected pet dog is brought into their home. Our objectives were to describe the clinical presentation and outcomes in dogs treated for B canis and evaluate the performance of the quantitative serologic canine Brucella multiplex (CBM) assay for monitoring treatment response. ANIMALS: Diagnostic records from the Animal Health Diagnostic Center at Cornell University were retrospectively reviewed (2017-2022) for dogs that underwent repeat B canis serologic testing. Medical records were requested to compare the clinical presentations and outcomes for dogs that underwent treatment for B canis. Changes in CBM antibody values were compared between dogs with and without resolution of clinical signs. RESULTS: While treatment protocols varied in the 30 treated dogs meeting the inclusion criteria, poly-antimicrobial therapy was prescribed in 97% (29/30) of cases. Gait abnormalities, spinal pain, and discospondylitis were the most common clinical abnormalities. A difference (P value = .0075) in the percent decrease in CBM assay PO1 antibody values was found in dogs with resolved clinical signs. CLINICAL RELEVANCE: Young dogs presenting with recurring lameness or back pain should be screened for B canis infection. A 40% decline in CBM assay values 2 to 6 months posttreatment can be supportive of response to treatment. Further prospective studies are needed to determine the ideal B canis treatment regimen and the magnitude of public health risks associated with maintaining neutered B canis-infected animals as pets.

Complete blood count and biochemistry reference intervals for healthy adult sheep in the northeastern United States.

BACKGROUND: Reference intervals (RIs) for routine clinicopathologic data in sheep are sparse. The authors sought to establish hematologic and biochemical RIs from a varied ovine population to improve data interpretation for small ruminant veterinarians. OBJECTIVES: The goal of this study was to establish ovine CBC and biochemistry reference intervals by sampling 120 healthy adult sheep, both male and female, from a variety of breeds, located in the Northeastern United States. METHODS: One hundred and eighteen sheep were included in the CBC RI and 121 sheep were included in the biochemistry panel RI. RESULTS: RIs for 42 CBC and biochemistry analytes were established in accordance with the American Society for Veterinary Clinical Pathology and Clinical Laboratory Standards Institute guidelines. CONCLUSIONS: These RIs are provided to assist small ruminant veterinarians with the interpretation of CBC and biochemistry panel results in sheep.

Outbreak of botulism type A in dairy cows detected by MALDI-TOF mass spectrometry.

Twenty-eight lactating dairy cattle in New York State were exposed to botulism toxin; 12 died and 16 recovered but never returned to full productivity. Pieces of a raccoon carcass were found in the total mixed ration on the first day of the outbreak. Clinical signs included anorexia, decreased milk production, decreased tongue tone, profound weakness, and recumbency. Clostridium botulinum type A (BoNT/A) was detected in rumen contents from 2 deceased cows via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In addition, C. botulinum type C was cultured from the liver of a third cow, and C. botulinum neurotoxin-producing type C gene (bont/C) was detected via real-time PCR. On postmortem examination, 4 cows had findings suggestive of toxic myopathy, but the cause and significance of these lesions is unknown given that botulism is typically not associated with gross or histologic lesions. This outbreak of BoNT/A in cattle in North America was diagnosed via MALDI-TOF MS, a rapid and sensitive modality for detection of botulinum preformed neurotoxin.