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Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Infectious respiratory disease is a common cause of morbidity among racehorses. Quantification of contact patterns in training facilities could help inform disease prevention strategies. The study objectives were to: i) describe the contact network among horses, locations, and humans at a Standardbred horse training facility in Ontario; ii) describe the characteristics of highly influential individuals; and iii) investigate how management changes alter the network metrics and discuss the potential implications for disease transmission. Proximity loggers detected contacts among horses, staff, and locations ( n = 144). Network metrics and node centrality measures were described for a 2-mode and horse-only contact network. The 2-mode network density was 0.16. and the median node degree was 20 [interquartile range (IQR) = 12 to 27]. Yearlings and floating staff were most influential in the network suggesting biosecurity programs should emphasize reducing contacts in these groups. Removing highly influential staff or co-housing of age groups resulted in changes to network diameter and density., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Disease transmission models often assume homogenous mixing. This assumption, however, has the potential to misrepresent the disease dynamics for populations in which contact patterns are non-random. A disease transmission model with an SEIR structure was used to compare the effect of weighted and unweighted empirical equine contact networks to weighted and unweighted theoretical networks generated using random mixing. Equine influenza was used as a case study. Incidence curves generated with the unweighted empirical networks were similar in epidemic duration (5-8 days) and peak incidence (30.8-46.4%). In contrast, the weighted empirical networks resulted in a more pronounced difference between the networks in terms of the epidemic duration (8-15 days) and the peak incidence (5-25%). The incidence curves for the empirical networks were bimodal, while the incidence curves for the theoretical networks were unimodal. The incorporation of vaccination and isolation in the model caused a decrease in the cumulative incidence for each network, however, this effect was only seen at high levels of vaccination and isolation for the complete network. This study highlights the importance of using empirical networks to describe contact patterns within populations that are unlikely to exhibit random mixing such as equine populations.

Background: Contact networks can be used to assess disease spread potential within a population. However, the data required to generate the networks can be challenging to collect. One method of collecting this type of data is by using radio-frequency identification (RFID) tags. The OpenBeacon RFID system generally consists of tags and readers. Communicating tags should be within 10m of the readers, which are powered by an external power source. The readers are challenging to implement in agricultural settings due to the lack of a power source and the large area needed to be covered., Methods: OpenBeacon firmware was modified to use the tag's onboard flash memory for data storage. The tags were deployed within an equine facility for a 7-day period. Tags were attached to the horses' halters, worn by facility staff, and placed in strategic locations around the facility to monitor which participants had contact with the specified locations during the study period. When the tags came within 2m of each other, they recorded the contact event participant IDs, and start and end times. At the end of the study period, the data were downloaded to a computer and analyzed using network analysis methods., Results: The resulting networks were plausible given the facility schedule as described in a survey completed by the facility manager. Furthermore, changes in the daily facility operations as described in the survey were reflected in the tag-collected data. In terms of the battery life, 88% of batteries maintained a charge for at least 6 days. Lastly, no consistent trends were evident in the horses' centrality metrics., Discussion: This study demonstrates the utility of RFID tags for the collection of equine contact data. Future work should include the collection of contact data from multiple equine facilities to better characterize equine disease spread potential in Ontario., Competing Interests: The authors have declared that no competing interests exist.

Contact networks can be analyzed to assess the potential for disease spread throughout the network. The lack of Canadian facility-level equine contact data makes the characterization of the equine contact structure difficult. Therefore, the purpose of this study was to use empirical contact data to characterize and compare equine network characteristics between equine facilities in Ontario. Contact pattern data from 4 equine facilities were collected using radio-frequency identification tags. The collected data were used to form 7 static contact networks (1 for each study day) for each facility. The assumption of homogenous mixing, where each individual in a population has an equal probability of coming in contact, was assessed for each network, since homogenous mixing is often used to describe mixing patterns in disease transmission models. At the facility level, neither the day-long static networks, nor a combined, week-long network were representative of homogenous mixing. The Jaccard Similarity Index indicated that 11-62% of the contacts were repeated throughout the study period. A network generated with survey-based data enabled the prediction of 8.7-79.6% of the contacts that were recorded with the RFID tags. With respect to the node centrality, the normalized node degree ranged from 0.0 to 0.96, with a mean of 0.31. The node strength ranged from 0 to 1 with a mean of 0.38. For both the node degree and node strength, a node's centrality score relative to the other nodes' centrality scores tended to be consistent throughout the study week. A significant (p < 0.05), weak positive correlation existed between the node degree and strength (0.41 < r < 0.54). The normalized betweenness centrality ranged from 0.00 to 1.00, with a mean of 0.11. Lastly, an exponential random graph model was used to quantify the relationship between the distance between the horses' stalls and edge formation. The distance parameter was not significant for all of the facilities. To conclude, the non-homogenous nature of the contact patterns, coupled with the large range of the centrality measures indicate the importance of using empirical data to understand processes such as disease spread potential within equine populations. Although the collection of a full set of data is optimal, the study results suggest an ability to infer contact networks using observational data in situations where little-to-no data exist. This study serves as a starting point for the characterization of equine contact networks in Ontario., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)