E. Paul J. Gibbs

The evolution of One Health: a decade of progress and challenges for the future

The One Health concept is gathering momentum and, over the next 12 months, Veterinary Record will be publishing a series of articles to help encourage that process. Written by specialists in a range of fields, the articles will consider the meaning of One Health, the interactions between animal and human health and how a collaborative and interdisciplinary approach could help to solve emerging global problems. To set the scene, Paul Gibbs outlines the recent history of One Health, discusses current challenges and muses on what the future might hold.

Equine and canine influenza: a review of current events

Abstract In the past decade, the pandemics of highly pathogenic avian influenza H5N1 and the novel H1N1 influenza have both illustrated the potential of influenza viruses to rapidly emerge and spread widely in animals and people. Since both of these viruses are zoonotic, these pandemics have been the driving force behind a renewed commitment by the medical and veterinary professions to practice One World, One Health for the control of infectious diseases. The discovery in 2004 that an equine origin H3N8 influenza virus was the cause of an extensive epidemic of respiratory disease in dogs in the USA came as a surprise; at that time dogs were thought to be refractory to infection with influenza viruses. In 2007, a second emerging canine influenza was confirmed in Korea, but this time the causal virus was an H3N2 avian influenza virus. This review focuses on recent events associated with equine and canine influenza viruses. While these viruses do not appear to be zoonotic, the close association between humans and dogs, and to a lesser extent horses, demands that we develop better surveillance and control strategies for emerging diseases in companion animals within the context of One World, One Health.

IXODID TICKS ON FERAL SWINE IN FLORIDA

More than 99% of the 645 feral swine (Sus scrofa L.) in southern Florida harbored ixodid ticks. Dermacentor variabilis (American dog tick) was present on 99.6% of the swine and comprised 82.5% of the ticks collected. Amblyomma maculatum (Gulf Coast tick) occurred on 85.9% of the hosts and 17.4% of the collections were of this species. Amblyomma americanum (Lone Star tick) and Ixodes scapularis (Black-legged tick) were found infrequently and together constituted <0.1% of the ticks. Pigs were infested by 7–22 days of age and 95% carried ticks by 6 wk of age. Only adult ticks were found on swine from southern Florida, but immature stages of A. americanum were present from a small sample of swine from northern Florida. Each species had a different pattern of distribution on the feral swine. No Ornithodoros species were found among the 36,616 ticks collected from feral swine during this survey.

A survey of eastern equine encephalomyelitis in Florida horses: Prevalence, economic impact, and management practices, 1982–1983

Abstract In spite of the availability of vaccines, eastern equine encephalomyelitis (EEE) virus continues to cause significant death losses in Florida horses. Veterinarians engaged in equine practice in Florida were surveyed regarding their experiences with EEE, and their responses were compared with serologic data available from the State of Florida Animal Disease Diagnostic Laboratory for 1982 and 1983. On the assumption that most cases of encephalitis in Florida are caused by EEE virus, considerable under-reporting was apparent. Clinical cases of EEE were comfirmed in every month of the year with the highest incidence observed in June and July. Northern and central Florida had the highest number of cases reported. Most deaths (78%) occurred in unvaccinated animals, indicating that greater horse owner awareness is needed. Deaths in vaccinated animals raised questions of the efficacy of current vaccines or their schedule of administration particularly in young horses. Vaccination schedule recommendations were variable between veterinarians with regard to annual versus semiannual EEE vaccination and age of first vaccination for foals. A conservative estimate of the cost to EEE to the state equine industry was greater than

Prevalence of and exposure factors for seropositivity to H3N8 canine influenza virus in dogs with influenza-like illness in the United States.

1 000 000 per year.

Seasonal and interseasonal dynamics of bluetongue virus infection of dairy cattle and Culicoides sonorensis midges in northern California--implications for virus overwintering in temperate zones.

OBJECTIVE To estimate the seroprevalence of antibodies against H3N8 canine influenza virus (CIV) in a population of US dogs with influenza-like illness (ILI) and to identify factors associated with seropositivity. DESIGN Cross-sectional study. ANIMALS 1,268 pet and shelter dogs with ILI in 42 states. PROCEDURES Serum samples collected from dogs from 2005 through June 2009 were tested for H3N8 CIV antibodies with a hemagglutination inhibition assay. Intrinsic factors (age, breed, and sex), extrinsic factors (dogs housed in a shelter facility, boarding kennel, or other setting), and geographic region (southwest, west, Midwest, southeast, and northeast) were compared between seropositive and seronegative dogs to identify variables associated with seropositivity. RESULTS Most (750/1,268 [59%]) dogs in the study were from Colorado, Florida, or New York. The overall seroprevalence of antibodies against H3N8 CIV was 49% (618/1,268 dogs; 95% confidence interval, 46% to 51%). The annual prevalence of H3N8 CIV seropositivity increased from 2005 (44%) to 2006 (53%) and 2007 (62%), then decreased in 2008 (38%) and 2009 (15%). The likelihood of H3N8 CIV seropositivity was associated with geographic region (southeast during 2005, west and northeast during 2006 and 2007, and northeast during 2008) and exposure setting (dogs housed in a shelter facility or boarding kennel during 2005 and 2006). CONCLUSIONS AND CLINICAL RELEVANCE Results of this study suggested there is a need for continued surveillance for H3N8 CIV infection in dogs in the United States and that personnel in communal dog-housing facilities should formulate, implement, and evaluate biosecurity protocols to reduce the risk of CIV transmission among dogs.

Preliminary studies on the Culicoides spp. as potential vectors of bluetongue in the Caribbean region

Bluetongue virus (BTV) is the cause of an economically important arboviral disease of domestic and wild ruminants. The occurrence of BTV infection of livestock is distinctly seasonal in temperate regions of the world, thus we determined the dynamics of BTV infection (using BTV-specific real time reverse transcriptase polymerase chain reaction) among sentinel cattle and vector Culicoides sonorensis (C. sonorensis) midges on a dairy farm in northern California throughout both the seasonal and interseasonal (overwintering) periods of BTV activity from August 2012 until March 2014. The data confirmed widespread infection of both sentinel cattle and vector midges during the August – November period of seasonal BTV transmission, however BTV infection of parous female midges captured in traps set during daylight hours also was detected in February of both 2013 and 2014, during the interseasonal period. The finding of BTV-infected vector midges during mid-winter suggests that BTV may overwinter in northern California by infection of long-lived female C. sonorensis midges that were infected during the prior seasonal period of virus transmission, and reemerged sporadically during the overwintering period; however the data do not definitively preclude other potential mechanisms of BTV overwintering that are also discussed.

Epidemiology of Bluetongue Viruses in the American Tropics

Abstract Ten species of Culicoides , namely C. pusillus, C. furens, C. foxi, C. jamaicensis, C. phlebotomus, C. trilineatus, C. borinqueni, C. paraensis and C. hoffmani were collected by light trap near livestock in Puerto Rico, St. Croix, and Barbados. Culicoides insignis and C. pusillus were the most numerous species collected, were collected from all three islands, and were at their peak populations during the time that most sentinel calves seroconverted to bluetongue virus in Puerto Rico. Therefore, they must be considered prime candidates as vectors of bluetongue virus in the region.

Bivens arm virus: a new rhabdovirus isolated from Culicoides insignis in Florida and related to Tibrogargan virus of Australia.

A study of the epidemiology of bluetongue viruses is in progress with the collaboration of 11 Central American and Caribbean countries. To date, over 200 bluetongue virus isolates have been obtained from cattle and sheep in sentinel groups distributed in the participating countries. Bluetongue serotypes identified include 1, 3, 6, and 12, virus types not previously recorded in the Western Hemisphere. Although the clinical impact of bluetongue virus infections in this hyperendemic environment appears to be minimal, the ubiquity of infection causes restrictions on the export of ruminant livestock and germ plasm. The stability of the Caribbean region ecosystem and the long-range implications of the interface with the northern temperate bluetongue virus ecosystem are reviewed.

Diagnostic performance of the canine Influenza A Virus subtype H3N8 hemagglutination inhibition assay

During field studies in 1981 on the transmission of bluetongue viruses in ruminants in Florida, a virus was isolated from Culicoides insignis collected near water buffalo (Bubalus bubalis) recently imported from Trinidad. Electron microscopy showed that this isolate, for which the name Bivens Arm virus is proposed, has rhabdovirus morphology. Serologic comparisons were made with recognized rhabdoviruses from terrestrial vertebrates and hematophagous arthropods. Indirect fluorescent antibody, complement fixation and neutralization tests indicated antigenic reactivity between Bivens Arm virus and two rhabdoviruses found only in Australia, Tibrogargan and Coastal Plains viruses. The Australian isolates cause subclinical infections in cattle and water buffalo and are believed to be transmitted by Culicoides. Initially, it was thought that Bivens Arm virus may have been introduced to Florida with the water buffalo from Trinidad, but a serologic survey of cattle serum, collected before the importation of the buffalo revealed antibody to the virus in cattle on farms located in diverse areas of Florida.