Search

OBJECTIVE To provide epidemiological information on the occurrence of animal and human rabies in the US during 2021 and summaries of 2021 rabies surveillance for Canada and Mexico. PROCEDURES State and territorial public health departments and USDA Wildlife Services provided data on animals submitted for rabies testing in 2021. Data were analyzed temporally and geographically to assess trends in domestic animal and wildlife rabies cases. RESULTS During 2021, 54 US jurisdictions reported 3,663 rabid animals, representing an 18.2% decrease from the 4,479 cases reported in 2020. Texas (n = 456 [12.4%]), Virginia (297 [8.1%]), Pennsylvania (287 [7.8%]), North Carolina (248 [6.8%]), New York (237 [6.5%]), California (220 [6.0%]), and New Jersey (201 [5.5%]) together accounted for > 50% of all animal rabies cases reported in 2021. Of the total reported rabid animals, 3,352 (91.5%) involved wildlife, with bats (n = 1,241 [33.9%]), raccoons (1,030 [28.1%]), skunks (691 [18.9%]), and foxes (314 [8.6%]) representing the primary hosts confirmed with rabies. Rabid cats (216 [5.9%]), cattle (40 [1.1%]), and dogs (36 [1.0%]) accounted for 94% of rabies cases involving domestic animals in 2021. Five human rabies deaths were reported in 2021. CLINICAL RELEVANCE The number of animal rabies cases reported in the US decreased significantly during 2021; this is thought to be due to factors related to the COVID-19 pandemic.

OBJECTIVE To provide epidemiological information on animal and human cases of rabies in the US during 2020 and summaries of 2020 rabies surveillance for Canada and Mexico. ANIMALS All animals submitted for laboratory diagnosis of rabies in the US during 2020. PROCEDURES State and territorial public health departments and USDA Wildlife Services provided 2020 rabies surveillance data. Data were analyzed temporally and geographically to assess trends in domestic and wildlife rabies cases. RESULTS During 2020, 54 jurisdictions submitted 87,895 animal samples for rabies testing, of which 85,483 (97.3%) had a conclusive (positive or negative) test result. Of these, 4,479 (5.2%) tested positive for rabies, representing a 4.5% decrease from the 4,690 cases reported in 2019. Texas (n = 580 [12.9%]), Pennsylvania (371 [8.3%]), Virginia (351 [7.8%]), New York (346 [7.7%]), North Carolina (301 [6.7%]), New Jersey (257 [5.7%]), Maryland (256 [5.7%]), and California (248 [5.5%]) together accounted for > 60% of all animal rabies cases reported in 2020. Of the total reported rabid animals, 4,090 (91.3%) involved wildlife, with raccoons (n = 1,403 [31.3%]), bats (1,400 [31.3%]), skunks (846 [18.9%]), and foxes (338 [7.5%]) representing the primary hosts confirmed with rabies. Rabid cats (288 [6.4%]), cattle (43 [1.0%]), and dogs (37 [0.8%]) accounted for 95% of rabies cases involving domestic animals in 2020. No human rabies cases were reported in 2020. CONCLUSIONS AND CLINICAL RELEVANCE For the first time since 2006, the number of samples submitted for rabies testing in the US was < 90,000; this is thought to be due to factors related to the COVID-19 pandemic, as similar decreases in sample submission were also reported by Canada and Mexico.

Rabies virus (RABV) is a deadly zoonosis that circulates in wild carnivore populations in North America. Intensive management within the USA and Canada has been conducted to control the spread of the raccoon (Procyon lotor) variant of RABV and work towards elimination. We examined RABV occurrence across the northeastern USA and southeastern Québec, Canada during 2008–2018 using a multi-method, dynamic occupancy model. Using a 10 km × 10 km grid overlaid on the landscape, we examined the probability that a grid cell was occupied with RABV and relationships with management activities (oral rabies vaccination (ORV) and trap-vaccinate-release efforts), habitat, neighbour effects and temporal trends. We compared raccoon RABV detection probabilities between different surveillance samples (e.g. animals that are strange acting, road-kill, public health samples). The management of RABV through ORV was found to be the greatest driver in reducing the occurrence of rabies on the landscape. Additionally, RABV occupancy declined further with increasing duration of ORV baiting programmes. Grid cells north of ORV management were at or near elimination ( $\hat{\psi }_{{\rm north}}$ = 0.00, s.e. = 0.15), managed areas had low RABV occupancy ( $\hat{\psi }_{{\rm managed}}$ = 0.20, s.e. = 0.29) and enzootic areas had the highest level of RABV occupancy ( $\hat{\psi }_{{\rm south}}$ = 0.83, s.e. = 0.06). These results provide evidence that past management actions have been being successful at the goals of reducing and controlling the raccoon variant of RABV. At a finer scale we also found that vaccine bait type and bait density impacted RABV occupancy. Detection probabilities varied; samples from strange acting animals and public health had the highest detection rates. Our results support the movement of the ORV zone south within the USA due to high elimination probabilities along the US border with Québec. Additional enhanced rabies surveillance is still needed to ensure elimination is maintained.

OBJECTIVE To provide epidemiological information on animal and human cases of rabies occurring in the United States during 2019 and summaries of 2019 rabies surveillance for Canada and Mexico. ANIMALS All animals submitted for laboratory diagnosis of rabies in the United States during 2019. PROCEDURES State and territorial public health departments and USDA Wildlife Services provided data on animals submitted for rabies testing in the United States during 2019. Data were analyzed temporally and geographically to assess trends in domestic and wildlife rabies cases. RESULTS During 2019, 53 jurisdictions submitted 97,523 animal samples for rabies testing, of which 94,770 (97.2%) had a conclusive (positive or negative) test result. Of these, 4,690 tested positive for rabies, representing a 5.3% decrease from the 4,951 cases reported in 2018. Texas (n = 565 [12.0%]), New York (391 [8.3%]), Virginia (385 [8.2%]), North Carolina (315 [6.7%]), California (276 [5.9%]), and Maryland (269 [5.7%]) together accounted for almost half of all animal rabies cases reported in 2019. Of the total reported rabid animals, 4,305 (91.8%) were wildlife, with raccoons (n = 1,545 [32.9%]), bats (1,387 [29.6%]), skunks (915 [19.5%]), and foxes (361 [7.7%]) as the primary species confirmed with rabies. Rabid cats (n = 245 [5.2%]) and dogs (66 [1.4%]) accounted for > 80% of rabies cases involving domestic animals in 2019. No human rabies cases were reported in 2019. CONCLUSIONS AND CLINICAL RELEVANCE The overall number of animal rabies cases decreased from 2018 to 2019. Laboratory diagnosis of rabies in animals is critical to ensure that human rabies postexposure prophylaxis is administered judiciously.

Rabies lyssavirus (RABV) is enzootic in raccoons across the eastern United States. Intensive management of RABV by oral rabies vaccination (ORV) has prevented its spread westward and shown evidence of local elimination in raccoon populations of the northeastern US. The USDA, Wildlife Services, National Rabies Management Program (NRMP) collaborates with other agencies to implement broad-scale ORV and conducts extensive monitoring to measure the effectiveness of the management. Enhanced Rabies Surveillance (ERS) was initiated during 2005 and updated in 2016 to direct surveillance efforts toward higher-value specimens by assigning points to different methods of encountering specimens for collection (strange-acting, roadkill, surveillance-trapped, etc., specimen point values ranged from 1 to 15). We used the 2016–2019 data to re-evaluate the point values using a dynamic occupancy model. Additionally, we used ERS data from 2012–2015 and 2016–2019 to examine the impact that the point system had on surveillance data. Implementation of a point system increased positivity rates among specimens by 64%, indicating a substantial increase in the efficiency of the ERS to detect wildlife rabies. Our re-evaluation found that most points accurately reflect the value of the surveillance specimens. The notable exception was that samples from animals found dead were considerably more valuable for rabies detection than originally considered (original points = 5, new points = 20). This work demonstrates how specimen prioritization strategies can be used to refine and improve ERS in support of wildlife rabies management.

A necessary component of elimination programmes for wildlife disease is effective surveillance. The ability to distinguish between disease freedom and non‐detection can mean the difference between a successful elimination campaign and new epizootics. Understanding the contribution of different surveillance methods helps to optimize and better allocate effort and develop more effective surveillance programmes. We evaluated the probability of rabies virus elimination (disease freedom) in an enzootic area with active management using dynamic occupancy modelling of 10 years of raccoon rabies virus (RABV) surveillance data (2006–2015) collected from three states in the eastern United States. We estimated detection probability of RABV cases for each surveillance method (e.g. strange acting reports, roadkill, surveillance‐trapped animals, nuisance animals and public health samples) used by the USDA National Rabies Management Program. Strange acting, found dead and public health animals were the most likely to detect RABV when it was present, and generally detectability was higher in fall–winter compared to spring–summer. Found dead animals in fall–winter had the highest detection at 0.33 (95% CI: 0.20, 0.48). Nuisance animals had the lowest detection probabilities (~0.02). Areas with oral rabies vaccination (ORV) management had reduced occurrence probability compared to enzootic areas without ORV management. RABV occurrence was positively associated with deciduous and mixed forests and medium to high developed areas, which are also areas with higher raccoon (Procyon lotor) densities. By combining occupancy and detection estimates we can create a probability of elimination surface that can be updated seasonally to provide guidance on areas managed for wildlife disease. Synthesis and applications. Wildlife disease surveillance is often comprised of a combination of targeted and convenience‐based methods. Using a multi‐method analytical approach allows us to compare the relative strengths of these methods, providing guidance on resource allocation for surveillance actions. Applying this multi‐method approach in conjunction with dynamic occupancy analyses better informs management decisions by understanding ecological drivers of disease occurrence.

OBJECTIVE To describe rabies and rabies-related events occurring during 2017 in the United States. DESIGN Cross-sectional analysis of passive surveillance data. ANIMALS All animals submitted for laboratory diagnosis of rabies in the United States during 2017. PROCEDURES State and territorial public health departments provided data on animals submitted for rabies testing in 2017. Data were analyzed temporally and geographically to assess trends in domestic and sylvatic animal rabies cases. RESULTS During 2017, 52 jurisdictions reported 4,454 rabid animals to the CDC, representing a 9.3% decrease from the 4,910 rabid animals reported in 2016. Of the 4,454 cases of animal rabies, 4,055 (91.0%) involved wildlife species. Relative contributions by the major animal groups were as follows: 1,433 (32.2%) bats, 1,275 (28.6%) raccoons, 939 (21.1%) skunks, 314 (7.0%) foxes, 276 (6.2%) cats, 62 (1.4%) dogs, and 36 (0.8%) cattle. There was a 0.4% increase in the number of samples submitted for testing in 2017, compared with the number submitted in 2016. Two human rabies deaths were reported in 2017, compared with none in 2016. CONCLUSIONS AND CLINICAL RELEVANCE The overall number of reported cases of animal rabies has decreased over time. Laboratory testing of animals suspected to be rabid remains a critical public health function and continues to be a cost-effective method to directly influence human rabies postexposure prophylaxis recommendations.

OBJECTIVE To describe rabies and rabies-related events occurring during 2016 in the United States. DESIGN Observational study based on passive surveillance data. ANIMALS All animals submitted for rabies testing in the United States during 2016. PROCEDURES State and territorial public health programs provided data on animals submitted for rabies testing in 2016. Data were analyzed temporally and geographically to assess trends in domestic and sylvatic animal rabies cases. RESULTS During 2016, 50 states and Puerto Rico reported 4,910 rabid animals to the CDC, representing a 10.9% decrease from the 5,508 rabid animals reported in 2015. Of the 4,910 cases of animal rabies, 4,487 (91.4%) involved wildlife. Relative contributions by the major animal groups were as follows: 1,646 (33.5%) bats, 1,403 (28.6%) raccoons, 1,031 (21.0%) skunks, 313 (6.4%) foxes, 257 (5.2%) cats, 70 (1.4%) cattle, and 58 (1.2%) dogs. There was a 4.6% decrease in the number of samples submitted for testing in 2016, compared with the number submitted in 2015. No human rabies deaths were reported in 2016. CONCLUSIONS AND CLINICAL RELEVANCE Laboratory testing of animals suspected to be rabid remains a critical public health function and continues to be a cost-effective method to directly influence human rabies postexposure prophylaxis recommendations.

OBJECTIVE To describe rabies and rabies-related events occurring during 2018 in the United States. ANIMALS All animals submitted for laboratory diagnosis of rabies in the United States during 2018. PROCEDURES State and territorial public health departments provided data on animals submitted for rabies testing in 2018. Data were analyzed temporally and geographically to assess trends in domestic animal and wildlife rabies cases. RESULTS During 2018, 54 jurisdictions reported 4,951 rabid animals to the CDC, representing an 11.2% increase from the 4,454 rabid animals reported in 2017. Texas (n = 695 [14.0%]), Virginia (382 [7.7%]), Pennsylvania (356 [7.2%]), North Carolina (332 [6.7%]), Colorado (328 [6.6%]), and New York (320 [6.5%]) together accounted for almost half of all rabid animals reported in 2018. Of the total reported rabies cases, 4,589 (92.7%) involved wildlife, with bats (n = 1,635 [33.0%]), raccoons (1,499 [30.3%]), skunks (1,004 [20.3%]), and foxes (357 [7.2%]) being the major species. Rabid cats (n = 241 [4.9%]) and dogs (63 [1.3%]) accounted for > 80% of rabid domestic animals reported in 2018. There was a 4.6% increase in the number of samples submitted for testing in 2018, compared with the number submitted in 2017. Three human rabies deaths were reported in 2018, compared with 2 in 2017. CONCLUSIONS AND CLINICAL RELEVANCE The overall number of animal rabies cases increased from 2017 to 2018. Laboratory diagnosis of rabies in animals is critical to ensure that human rabies postexposure prophylaxis is administered judiciously.

OBJECTIVE To evaluate rabies virus (RABV) characterization data obtained from animal specimens submitted to the US public health rabies surveillance system and propose a standardized approach to sample selection for RABV characterization that could enhance early detection of important rabies epizootic events in the United States. SAMPLE United States public health rabies surveillance system data collected from January 1, 2010, through December 31, 2015. PROCEDURES Data were reviewed to identify RABV-positive specimens for which virus characterization would likely provide information regarding any of 4 overarching events (discovery of novel variants, translocation of RABV variants, host-shift events, and any unusual rabies-related event) that could substantially alter animal rabies epizootiology in the United States. These specimens were designated as specimens of epizootiological importance (SEIs). Estimates of the additional number of specimens that public health laboratories could expect to process each year if all SEIs underwent RABV characterization were calculated. RESULTS During the 6-year period, the mean annual number of SEIs was 855 (95% CI, 739 to 971); the mean number of SEIs that underwent virus characterization was 270 (95% CI, 187 to 353). Virus characterization of all SEIs would be expected to increase the public health laboratories’ test load by approximately 585 (95% CI, 543 to 625) specimens/y. CONCLUSIONS AND CLINICAL RELEVANCE Prioritization of RABV characterization of SEIs may improve early detection of rabies events associated with RABV host shifts, variant translocations, and importation. Characterization of SEIs may help refine wildlife rabies management practices. Each public health laboratory should evaluate testing of SEIs to ensure diagnostic laboratory capacity is not overstretched.

Intensive efforts are being made to eliminate the raccoon variant of rabies virus (RABV) from the eastern United States and Canada. The United States Department of Agriculture (USDA) Wildlife Services National Rabies Management Program has implemented enhanced rabies surveillance (ERS) to improve case detection across the extent of the raccoon oral rabies vaccination (ORV) management area. We evaluated ERS and public health surveillance data from 2006 to 2017 in three northeastern USA states using a dynamic occupancy modeling approach. Our objectives were to examine potential risk corridors for RABV incursion from the U.S. into Canada, evaluate the effectiveness of ORV management strategies, and identify surveillance gaps. ORV management has resulted in a decrease in RABV cases over time within vaccination zones (from occupancy ( &psi, &macr, ) of 0.60 standard error (SE) = 0.03 in the spring of 2006 to &psi, of 0.33 SE = 0.10 in the spring 2017). RABV cases also reduced in the enzootic area (from &psi, of 0.60 SE = 0.03 in the spring of 2006 to &psi, of 0.45 SE = 0.05 in the spring 2017). Although RABV occurrence was related to habitat type, greater impacts were associated with ORV and trap&ndash, vaccinate&ndash, release (TVR) campaigns, in addition to seasonal and yearly trends. Reductions in RABV occupancy were more pronounced in areas treated with Ontario Rabies Vaccine Bait (ONRAB) compared to RABORAL V-RG&reg, Our approach tracked changes in RABV occurrence across space and time, identified risk corridors for potential incursions into Canada, and highlighted surveillance gaps, while evaluating the impacts of management actions. Using this approach, we are able to provide guidance for future RABV management.

Laboratory-based surveillance is integral for rabies prevention, control and management efforts. While the DFA is the gold standard for rabies diagnosis, there is a need to validate additional diagnostic techniques to improve rabies surveillance, particularly in developing countries. Here, we present a standard protocol for the DRIT as an alternative, laboratory or field-based testing option that uses light microscopy as compared to the DFA. Touch impressions of brain tissue collected from suspect animals are fixed in 10% buffered formalin. The DRIT uses rabies virus-specific monoclonal or polyclonal antibodies (conjugated to biotin), a streptavidin-peroxidase enzyme, and a chromogen reporter (such as acetyl 3-amino-9-ethylcarbazole) to detect viral inclusions within infected tissue. In approximately 1 h, a brain tissue sample can be tested and interpreted by the DRIT. Evaluation of suspect animal brains tested from a variety of species in North America, Asia, Africa, and Europe have illustrated high sensitivity and specificity by the DRIT approaching 100% with results compared to DFA. Since 2005, the United States Department of Agriculture's Wildlife Services (USDA WS) program has conducted large-scale enhanced rabies surveillance efforts using the DRIT to test >94,000 samples collected from wildlife in strategic rabies management areas. The DRIT provides a powerful, economical tool for rabies diagnosis that can be used by laboratorians and field biologists to improve current rabies surveillance, prevention and control programs globally.

Due to an error during production, the order in which Figure 1 and Figure 2 appear and the linking of the Figure 1 and Figure 2 captions in the Results section of the published paper [1] were incorrect. A corrected version of the Figure order and associated captions is provided below[...]

International audience; Laboratory-based surveillance is fundamental to effective rabies prevention and control. The direct fluorescent antibody (AB) test (FAT) is the gold standard for rabies diagnosis. Recently, additional tests besides the FAT have been developed, such as the direct rapid immunohistochemical test (DRIT). In this study, our objective was to further refine technical aspects of the DRIT using a combination of two monoclonal ABs (MABs), 502 and 802, conduct additional testing among rabies reference laboratories using a diversity of animal species and rabies virus (RV) variants and compare the potential utility of the DRIT for end users via proficiency testing (PT) against the FAT. Considering the ideal molar ratios of biotin to AB in formulation of the DRIT conjugate, 3.9 was found to be superior to 7.4, for detection of RV antigens in the brain of a naturally infected raccoon. Optimization of the DRIT conjugate may also be dependent upon the apparent choice of specific viral antigens for testing, as a gray fox RV variant reacted less strongly than a raccoon RV variant in determining the working dilution of the MAB cocktail. Using the same MABs and protocol, the DRIT was compared to the FAT using more than 800 samples of mammalian brains, representative of more than 25 taxa, including in excess of 250 animal rabies cases from Europe and North America. Sensitivity was determined at 98% (96-100%, 95% CI) and specificity was calculated at 95% (92-96%, 95% CI). In a comparison among end users, PT of laboratory personnel resulted in values of 77-100% sensitivity and 86-100% specificity. Based upon these and previously reported results, the DRIT appears to be a suitable alternative to the FAT for use in lyssavirus diagnosis.

Lynx rufus (Bobcat) cover-type selection and activity patterns have been studied in a variety of landscapes in the southeastern United States, but effects of individual activity status (active or inactive) and time of day (day, night, crepuscular) on cover-type selection have not been investigated for this species. Therefore, we investigated Bobcat habitat use in a Pinus palustris (Longleaf Pine) forest in southwestern Georgia to determine whether activity status of individuals or time of day affected seasonal cover-type selection. We monitored 43 radiocollared Bobcats from 2001–2004 and determined habitat use at Johnson's third order of selection (i.e., habitat selection within the home range) using Euclidean distance-based analysis. Bobcats selected (Λ = 0.017, P = 0.001) habitat within their home ranges; however, although Bobcats are typically classified as crepuscular, neither activity status (Λ = 0.990, P = 0.981) nor time-of-day (Λ = 0.972, P = 0.647) affected cover-type selection. Bobcats ...

Understanding interactions among bobcats (Lynx rufus) may lend insight into less understood life history traits of the bobcat and improve management of the species. Moreover, data from manipulative experiments pertaining to bobcat ecology are largely absent from the scientific literature. Therefore, we investigated bobcat spatial organization and habitat use after an experimental population reduction on an 11,735-ha study site in southwestern Georgia, USA. In response to an approximate 50% population reduction, male bobcats shifted their space use (26.4 ± 1.7% more shift relative to baseline) more (F1,3 = 138.08, P = 0.001) than males where no bobcat removal occurred (28.1 ± 5.5% less shift relative to baseline). Dispersion of radio locations for all female bobcats increased following the population reduction; however, females that were exposed to the removal of a potentially interacting male remained more (F1,14 = 6.78, P = 0.021) static (increase in dispersion = 7.8 ± 7.3%) than females that we...

Lynx rufus (bobcat) home-range sizes have been studied throughout the Southeast, but study duration is generally ≤ 2 years and number of bobcats sampled is often < 20. There have been even fewer studies dealing with spatial interactions of bobcats, and fewer still within a Pinus palustris (longleaf pine) ecosystem. Because both bobcat home-range sizes and the degree that space is shared by bobcats are highly variable, it is important to understand factors that influence bobcat home-range size and spatial organization within the various habitats where this species is found. Therefore, we determined seasonal and annual home-range sizes and spatial overlap of bobcats in a longleaf pine forest in southwestern Georgia. We monitored 44 radio-collared bobcats (17 M and 27F) during 2001–2004. Gender and year did not interact to affect bobcat annual home-range sizes (95% adaptive kernel), and annual differences in annual home-range sizes were insignificant. However, male bobcats had annual home-range size...

Oral rabies vaccination (ORV) requires knowledge of the spatial-temporal distribution of rabies virus variants targeted for control. Rabies-exposure based public health surveillance alone may not provide a sound basis for ORV decisions. The value and cost of road kill surveys was evaluated for the late spring–early fall 2005–2007 as a part of enhanced rabies surveillance in northern New York, where raccoon rabies is enzootic and ORV has occurred since the late 1990s. Structured surveys were conducted to collect raccoons and other meso-carnivores for rabies testing at the New York State Rabies Laboratory. Of the 209 meso-carnivore heads collected and submitted for testing, 175 were testable by direct fluorescent antibody; none was rabid. Rabies was also not reported through public health surveillance in survey zones during 2005–2007. Overall, survey costs were $37,118 (2016 USD). Salaries and benefits accounted for 61% of costs, followed by fuel (22%), vehicle depreciation (14%), and sample shipping (3%). Mean daily distance driven was 303 ± 37 km and 381 ± 28 km for total road kills and raccoons, respectively. Costs/road kill collected and submitted was $176/all species and $224/raccoon. This study provides costs for planning road kill surveys and underscores the need to continually improve enhanced rabies surveillance approaches to support ORV decision making.