Rabies surveillance in the United States during 2019

Clinical Risk Assessment and Treatment of a Man Attacked by a Rabid North American Beaver (Castor canadensis) in the Connecticut River: Case Report

A 46-y-old male was swimming in the Connecticut River near Hatfield, Massachusetts, when he suffered an unprovoked attack from a North American beaver (Castor canadensis). The beaver attacked the man 3 separate times, inflicting multiple bite wounds to his arms and torso, ultimately attaching itself to his arm without releasing. The patient was brought to our emergency department, where the wounds were treated, and rabies postexposure prophylaxis was begun. The beaver tested positive for rabies shortly thereafter. Here we review the case of an unprovoked attack by a beaver and clinical risk assessment for rabies, along with management including postexposure prophylaxis, tetanus immunization, and wound care.

Rabies in Cats-An Emerging Public Health Issue

Human rabies cases today are predominantly associated with infection from rabid domestic dogs. Unlike dogs, a common global reservoir species that perpetuates rabies viruses (RABV) within their populations, domestic cats are much less frequently reported or vaccinated. Epidemiologically, cats are important vectors of lyssaviruses but are not viral reservoirs. Typically, cats are incidental hosts only, infected with the predominant lyssavirus in their geographic locale. Human cases associated with rabid cats have occurred in Africa, Asia, Europe and throughout the Americas. As adept, solitary hunters, wild and domestic felids are at risk of lyssavirus infection based upon interactions with infected prey, such as bats, or from transmission by other mesocarnivores, such as rabid dogs, foxes, jackals, raccoons, and skunks. Current veterinary vaccines provide safe and effective immunity in cats against phylogroup I lyssaviruses, such as RABV, but not against divergent lyssaviruses in phylogroups II-IV. With the focus upon the global elimination of canine rabies, the emergence of rabies in cats represents a concerning trend. Clearly, education about the occurrence of rabies in cats needs to be improved, as well as the routine vaccination of cats to reduce the associated risks to public health, agriculture, and conservation biology from a One Health perspective.

Dogs on the move: Estimating the risk of rabies in imported dogs in the United States, 2015-2022

BACKGROUND

Dog-mediated rabies virus variant (DMRVV), a zoonotic pathogen that causes a deadly disease in animals and humans, is present in more than 100 countries worldwide but has been eliminated from the United States since 2007. In the United States, the U.S. Centers for Disease Control and Prevention has recorded four instances of rabies in dogs imported from DMRVV-enzootic countries since 2015. However, it remains uncertain whether the incidence of DMRVV among imported dogs from these countries significantly surpasses that of domestically acquired variants among domestic U.S. dogs.

AIM

This evaluation aimed to estimate the number of dogs imported from DMRVV-enzootic countries and compare the risk of rabies between imported dogs and the U.S. domestic dog population.

MATERIALS AND METHODS

Data from the CDC's dog import permit system (implemented during 2021 under a temporary suspension of dog importation from DMRVV-enzootic countries) and U.S. Customs and Border Protection's Automated Commercial Environment system, each of which records a segment of dogs entering the U.S. from DMRVV-enzootic countries, was analysed. Additionally, we estimated the incidence rate of rabies in dogs imported from DMRVV-enzootic countries and compared it to the incidence rate within the general U.S. dog population, due to domestically acquired rabies variants, over the eight-year period (2015-2022).

RESULTS

An estimated 72,589 (range, 62,660-86,258) dogs were imported into the United States annually between 2015 and 2022 from DMRVV-enzootic countries. The estimated incidence rate of rabies was 16 times higher (range, 13.2-19.4) in dogs imported from DMRVV-enzootic countries than that estimated for domestically acquired rabies in the general U.S. dog population.

CONCLUSIONS

Preventing human exposure to dogs with DMRVV is a public health priority. The higher risk of rabies in dogs imported from DMRVV-enzootic countries supports the need for importation requirements aimed at preventing the reintroduction of DMRVV into the United States.

Animal Bites and Attacks

This text serves to familiarize readers with animal bites and attacks. Topics include appropriate management of animal bite wounds, postexposure prophylaxis for possible rabies exposures, and unique infectious diseases transmitted through animal vectors. Large mammal attacks are discussed, in addition to the management of smaller animal attacks and exposures.

Public perceptions of free-roaming dogs and cats in India and the United States

In this cross-sectional study, we aimed to describe differences between India and the United States in public perceptions of free-roaming dogs and cats, concerns related to free-roaming animals, and preferred strategies for veterinary medical interventions and population management. Between August 2021 and February 2022, 498 individuals completed an online survey including 210 Indian respondents and 288 American respondents. Free-roaming dogs and cats were largely perceived as community animals among Indian respondents, with significantly more respondents indicating they should be allowed to roam freely compared with American respondents. Respondents from both countries were concerned about animal welfare, although Americans were significantly more likely to list animal welfare, public health and wildlife risks as significant concerns related to free-roaming cats and dogs. American respondents were also more likely to support adoption for sociable animals and euthanasia for unsociable animals, whereas Indian respondents were more likely to support spay/neuter, vaccinate and release strategies for both dogs and cats. Our findings speak to the importance of implementing tailored strategies for free-roaming cat and dog management based on local cultures and community perceptions of free-roaming animals.

Fatal Human Rabies Infection With Suspected Host-Mediated Failure of Post-Exposure Prophylaxis Following a Recognized Zoonotic Exposure-Minnesota, 2021

BACKGROUND

No human rabies post-exposure prophylaxis (PEP) failure has been documented in the United States using modern cell culture-based vaccines. In January 2021, an 84-year-old male died from rabies 6 months after being bitten by a rabid bat despite receiving timely rabies PEP. We investigated the cause of breakthrough infection.

METHODS

We reviewed medical records, laboratory results, and autopsy findings and performed whole-genome sequencing (WGS) to compare patient and bat virus sequences. Storage, administration, and integrity of PEP biologics administered to the patient were assessed; samples from leftover rabies immunoglobulin were evaluated for potency. We conducted risk assessments for persons potentially exposed to the bat and for close patient contacts.

RESULTS

Rabies virus antibodies present in serum and cerebrospinal fluid were nonneutralizing. Antemortem blood testing revealed that the patient had unrecognized monoclonal gammopathy of unknown significance. Autopsy findings showed rabies meningoencephalitis and metastatic prostatic adenocarcinoma. Rabies virus sequences from the patient and the offending bat were identical by WGS. No deviations were identified in potency, quality control, administration, or storage of administered PEP. Of 332 persons assessed for potential rabies exposure to the case patient, 3 (0.9%) warranted PEP.

CONCLUSIONS

This is the first reported failure of rabies PEP in the Western Hemisphere using a cell culture-based vaccine. Host-mediated primary vaccine failure attributed to previously unrecognized impaired immunity is the most likely explanation for this breakthrough infection. Clinicians should consider measuring rabies neutralizing antibody titers after completion of PEP if there is any suspicion for immunocompromise.

RABIES IN RODENTS AND LAGOMORPHS IN THE USA, 2011-20

Rabies is an acute progressive encephalitis caused by infection with rabies viruses, with reservoirs among bats and mesocarnivores, but all mammals are susceptible. Despite its distribution and abundance, cases of rabies are much less common in rodents and lagomorphs. Familiarity with current rabies prevalence data is important for informed decisions on human postexposure prophylaxis after rodent and lagomorph bites. This study is an update of rabies cases reported in rodents and lagomorphs in the US from 2011 to 2020. Rabies reports were collected passively from laboratory testing agencies in the US and Puerto Rico from 2011 to 2020. Descriptive analysis was conducted to determine the percent positivity of rabies cases by species. A total of 401 cases of rabies in rodents and lagomorphs were reported from 2011 to 2020. Most reported cases were in groundhogs (Marmota monax), representing >90% of cases, and the trend closely aligned with rabies in raccoons (Procyon lotor). In any given year, the percent positivity of rabies in rodents and lagomorphs was <2.5%, and the trend of percent positivity from 2011 to 2020 was stable. Groundhog and North American beaver (Castor canadensis) percent positivity was significantly higher than the rest of the rodents and lagomorphs. Most rabies cases occurred during the months of May-September. Documented cases of rabies in rodents and lagomorphs are generally rare, but with variation between species. Groundhogs and North American beavers had rabies percent positivity similar to high-risk species, such as bats and raccoons, and constituted 97% of all rodent and lagomorph positive cases. Since 1993, the trend in rabies cases in groundhogs has significantly declined. These results can be used to help inform public health officials on rodent and lagomorph prevention and control efforts, as well as rabies postexposure prophylaxis.

Cat rabies in Brazil: a growing One Health concern

This review of human and cat rabies from 1986 to 2022 has shown mostly AgV3 variant in human cases with 29/45 (64.4%) reports including 23 from bats, four from cats, and two from unknown species, followed by 8/45 (17.8%) of AgV2 variant (all from dogs), 4/45 from marmoset variant (all from Callithrix jacchus), 2/45 samples compatible with wild canid variant (both from Cerdocyon thous), and one/45 of AgV1 variant from a domestic dog. Only one sample of human rabies was not typified, related to bat aggression. In addition, surveillance conducted in the state of São Paulo confirmed the presence of rabies in 7/23,839 cats (0.031%) and 3/106,637 dogs (0.003%) between 2003 and 2013, with a 10:1 overall cat-to-dog positivity ratio. This 10-fold higher infection rate for cat rabies may be explained by cats' hunting habits and predation. In addition, after 28 years of rabies-free status, a new cat rabies case was reported in the city of São Paulo in 2011. The rabid cat lived, along with other pets, in a household located near the largest downtown city park, whose owners presented animal hoarding behavior. Thus, animal hoarders and rescuers, public health agents, animal health professionals, and the general population with contact need to be aware of the risk of bat-borne rabies followed by spillover from cats to humans. In conclusion, cat rabies cases are becoming increasingly important in Brazil. This poses a One Health concern, given the overlapping of human, bat and cat populations within the same predisposed environment.

Risk of Rabies and Implications for Postexposure Prophylaxis Administration in the US

Importance

In the US, rabies postexposure prophylaxis (PEP) is often administered without a comprehensive and regionally appropriate rabies risk assessment. For low-risk exposures, this can result in patients incurring out-of-pocket expenses or experiencing adverse effects of PEP unnecessarily.

Objective

To use a model to estimate (1) the probability that an animal would test positive for rabies virus (RABV) given that a person was exposed, and (2) the probability that a person would die from rabies given that they were exposed to a suspect rabid animal and did not receive PEP, and to propose a risk threshold for recommending PEP according to model estimates and a survey.

Design, Setting, and Participants

In this decision analytical modeling study, positivity rates were calculated using more than 900 000 animal samples tested for RABV between 2011 and 2020. Other parameters were estimated from a subset of the surveillance data and the literature. Probabilities were estimated using Bayes' rule. A survey was administered among a convenience sample of state public health officials in all US states (excluding Hawaii) plus Washington, DC and Puerto Rico to determine a risk threshold for PEP recommendation. Respondents were asked whether they would recommend PEP given 24 standardized exposure scenarios while accounting for local rabies epidemiology.

Main Outcomes and Measures

A quantitative and regionally appropriate approach for helping health care practitioners and public health professionals determine whether to recommend and/or administer rabies PEP.

Results

A total of 1728 unique observations were obtained from the model for the probability that an animal would test positive for RABV given that a person was exposed, and 41 472 for ) the probability that a person would die from rabies given that they were exposed to a suspect rabid animal and did not receive PEP. The median probability that an animal would test positive for RABV given that a person was exposed ranged from 3 × 10-7 to 0.97, while the probability that a person would die from rabies given that they were exposed to a suspect rabid animal and did not receive PEP ranged from 1 × 10-10 to 0.55. Fifty public health officials out of a target sample size of 102 responded to the survey. Using logistic regression, a risk threshold was estimated for PEP recommendation of 0.0004; PEP may not be recommended for exposures with probabilities below this threshold.

Conclusions and Relevance

In this modeling study of rabies in the US, the risk of death|exposure was quantified and a risk threshold was estimated. These results could be used to inform the decision-making process as to the appropriateness of recommending rabies PEP.

Electronic application for rabies management improves surveillance, data quality, and investigator experience in Haiti

Background

Integrated bite case management (IBCM) is a multi-sectoral response to animal-bites which reduces human and canine rabies mortality through animal quarantine, bite-victim counseling, and vaccination tracking. Haiti's national rabies surveillance program was established in 2013 using paper-based IBCM (pIBCM) with adoption of an electronic smartphone application (eIBCM) in 2018.

Methods

We evaluated the feasibility of implementing the electronic app in Haiti and compared pIBCM and eIBCM data quality collected January 2013–August 2019. Deaths prevented, cost-per-death averted, and cost-per-investigation during use of pIBCM and eIBCM were estimated using a previously validated rabies cost-effectiveness tool that accounted for bite-victim demographics; probability of acquiring rabies; post-exposure prophylaxis; and costs including training, supplies, and salaries. We compared pIBCM and eIBCM based on data comprehensiveness, completeness, and reporting efficiency. Surveys were administered to IBCM staff to evaluate the usefulness, simplicity, flexibility, and acceptability of eIBCM.

Results

Of 15,526 investigations, 79% were paper-based and 21% electronic. IBCM prevented 241 (estimated) human rabies deaths. Using pIBCM, cost-per-death averted was $2,692 and the cost-per-investigation was $21.02; up to 55 data variables were collected per investigation; data transmission took 26 days to reach national staff, and 180 days until analysis. Using eIBCM, the cost-per-death averted was $1,247 and the cost-per-investigation was $22.70; up to 174 data variables were collected per investigation; data transmission took 3 days to reach national staff, and 30 days until analysis. Among 12,194 pIBCM investigations, 55% were mappable by commune, compared to 100% of eIBCM investigations mappable by GPS. Animal case definitions were incorrectly ascribed by investigators in 5.5% of pIBCM investigations and zero for eIBCM; typically, errors were in determining probable vs. suspect case assignments. Overall, eIBCM was well-accepted by staff, who reported the app is easy-to-use, facilitates investigations, and compared to pIBCM hastens data reporting.

Discussion

In Haiti, eIBCM showed improved data completeness, data quality, and shorter notification times with minimal increase in operational cost. The electronic app is simple-to-use and facilitates IBCM investigations. Rabies endemic countries could refer to eIBCM in Haiti as a cost-effective means to reduce human rabies mortality and improve surveillance capacity.

FACTORS IMPACTING SUCCESSFUL REHABILITATION OF BIG BROWN BATS (EPTESICUS FUSCUS) IN A WISCONSIN WILDLIFE REHABILITATION CENTER: A 5-YEAR RETROSPECTIVE

The big brown bat (Eptesicus fuscus; EPFU) is widely distributed throughout the Americas and plays critical roles in sustaining cave ecosystems and abating agricultural pests. In Wisconsin, EPFU is a threatened species with declining populations due to hibernacula disturbances, wind turbines, and habitat destruction. Due to their ecological and economic value, it is important to be able to release EPFU that enter wildlife rehabilitation centers back to the wild. This study evaluated the medical records of 454 EPFU (275 male, 179 female) admitted to a wildlife rehabilitation center in Wisconsin from 2015 to 2020. For each bat, the season at intake, examination findings, length of time in rehabilitation, and final outcome (released or not released) were recorded. Using a multiple variable logistic regression model, there was a statistically significant positive association between length of time in the rehabilitation center and likelihood of release (odds ratio [OR] 1.08; 95% CI 1.06-1.12); this association can be explained by the need to overwinter some otherwise healthy bats in rehabilitation during hibernation. The following examination findings were associated with a significantly lower likelihood of release: wing injury (OR 0.32; 95% CI 0.10-0.89) and decreased body condition (OR 0.29; 95% CI 0.12-0.64). When corrected for time spent in rehabilitation (potentially artificially lengthened due to hibernation), patients admitted in the summer and fall were less likely to be released than those admitted in the winter (OR 0.93; 95% CI 0.90-0.96 and OR 0.95; 95% CI 0.92-0.97, respectively). The results of this study can be used to help veterinarians and licensed rehabilitators better triage EPFU during admission to wildlife rehabilitation centers in order to improve management and promote successful release back to the wild.

A statewide, cross-sectional evaluation of the knowledge and level of concern of rabies among South Carolina residents

Animal rabies cases have increased steadily in South Carolina (SC) for the past decade. An understanding of the population's awareness and understanding of the disease is needed to tailor public health interventions. A marketing list-serv of SC residents' email addresses was used to recruit anonymous respondents for a Knowledge Attitudes and Practices (KAP) electronic survey. A total 516 South Carolinians completed the 31-question survey. Quantile regression and a Pearson's correlation evaluated potential associations between respondent's rabies knowledge and their attitudes and practices. Knowledge was assessed on topics of rabies biology, state animal case counts and rabies pet-related laws. Level of concern and level of knowledge were positively correlated. Additionally, statewide hotspot analysis revealed geographic areas warranting targeted public health interventions; counties with low public concern juxtapositioned with high animal rabies case counts. This study demonstrates the utility of statewide KAPs to gauge populations rabies perception and related preventative actions to tailor appropriate educational programs to limit human-animal rabies exposures.

RABIES DIAGNOSIS AND RESPONSE TO VACCINATION IN SOUTHERN TAMANDUA (TAMANDUA TETRADACTYLA)

Rabies has rarely been described in Xenarthra, and rabies vaccine response has not been documented. A southern tamandua (Tamandua tetradactyla) presented with nonspecific clinical signs and was euthanatized. Subsequently, immunohistochemistry and RT-PCR confirmed a rabies diagnosis. Following these tests, a group of eight captive tamanduas were vaccinated with a killed rabies vaccine, and titers were measured at the time of vaccination and 23 d later. One animal had day 0 titers suggestive of previous vaccination or exposure. All animals had detectable neutralizing rabies virus antibody titers after vaccination, but one animal failed to meet the World Organization for Animal Health's definition for adequate vaccination (≥0.5 IU/ml), and two other animals had low antibody titers (0.56 and 0.6 IU/ml). Rabies should be considered as a possible cause of illness in tamanduas, and rabies vaccination may be a useful preventative measure when anthropic interaction through medical care or ambassador roles is occurring.

Global burden of rabies in 204 countries and territories, from 1990 to 2019: results from the Global Burden of Disease Study 2019

OBJECTIVES

Rabies is an acute lethal infectious disease caused by a lyssavirus infection. In 2018, the World Health Organization proposed a global strategic plan to end human rabies deaths by 2030. However, systematic studies on the global rabies disease burden and epidemiological trends are scarce.

METHODS

We extracted the disease burden and epidemiological data of rabies worldwide in the preceding 30 years from the Global Burden of Disease Study 2019 and performed a comprehensive analysis.

RESULTS

In 2019, the incident cases of rabies worldwide were 14,075.51 (95% uncertainty interval: 6124.33-21,618.11), and the number of deaths was 13,743.44 (95% uncertainty interval: 6019.13-17,938.53), both of which were lower than that in 1990. With the improvement of the sociodemographic index, the incident cases, the number of deaths, age-standardized incidence rate, age-standardized incidence death rate, and disability-adjusted life years of rabies all showed downward trends. Adolescents and adults aged <50 years represented the majority of rabies cases worldwide.

CONCLUSION

The global disease burden of rabies has declined over the past 30 years. Furthermore, the disease burden of rabies was closely related to the sociodemographic index level.

Spatial and temporal overlap of domestic cats (Felis catus) and native urban wildlife

Free-roaming domestic cats (Felis catus) are known to pose threats to ecosystem health via transmission of zoonotic diseases and predation of native wildlife. Likewise, free-roaming cats are also susceptible to predation or disease transmission from native wildlife. Physical interactions are required for many of these risks to be manifested, necessitating spatial and temporal overlap between cats and wildlife species. Therefore, knowledge of the location and extent of shared habitat and activity periods would benefit management programs. We used data from a 3-year camera trap survey to model species-specific occupancy and identify landscape variables that contribute to the distribution of free-roaming domestic cats and eight native mammal species in Washington, DC. (USA). Our analysis includes five species that are common prey items of domestic cats, and three species that are potential disease vectors or are otherwise known to be a risk to cats. We then predicted the probability of occupancy and estimated the probability of spatial overlap between cats and each native wildlife species at multiple scales. We also used kernel density estimations to calculate temporal overlap between cats and each native wildlife species. Across spatial scales, occupancy for potential disease vector species was generally positively correlated with canopy cover and open water. Prey species were also generally positively correlated with canopy cover, but displayed negative associations with human population density and inconsistent associations with average per capita income. Domestic cat occupancy was negatively correlated with natural habitat characteristics and positively correlated with human population density. Predicted spatial overlap between domestic cats and native wildlife was greatest for potential disease vector species. Temporal overlap was high (&gt;0.50) between cats and all but two native wildlife species, indicating that temporal overlap is probable wherever species overlap spatially. Our findings indicate that the risk to and from domestic cats varies across urban landscapes, but primarily arises from human activities. As such, humans are implicated in the negative outcomes that result from cats interacting with wildlife. Data-driven management to reduce such interactions can aid in cat population management, biodiversity conservation, and public health campaigns.

Defining county-level terrestrial rabies freedom using the United States National Rabies Surveillance System: a surveillance data analysis (Preprint)

BACKGROUND

Rabies is a deadly zoonotic disease with nearly 100% fatality rate. In the United States, rabies virus persists in wildlife reservoirs, with occasional spillover into humans and domestic animals. The distribution of reservoir hosts in US counties plays an important role in public health decision-making, including the recommendation of lifesaving postexposure prophylaxis upon suspected rabies exposures. Furthermore, in surveillance data, it is difficult to discern whether counties have no cases reported because rabies was not present or because counties have an unreported rabies presence. These epizootics are monitored by the National Rabies Surveillance System (NRSS), to which approximately 130 state public health, agriculture, and academic laboratories report animal rabies testing statistics. Historically, the NRSS classifies US counties as free from terrestrial rabies if, over the previous 5 years, they and any adjacent counties did not report any rabies cases and they tested ≥15 reservoir animals or 30 domestic animals.

OBJECTIVE

This study aimed to describe and evaluate the historical NRSS rabies-free county definition, review possibilities for improving this definition, and develop a model to achieve more precise estimates of the probability of terrestrial rabies freedom and the number of reported county-level terrestrial rabies cases.

METHODS

Data submitted to the NRSS by state and territorial public health departments and the US Department of Agriculture Wildlife Services were analyzed to evaluate the historical rabies-free definition. A zero-inflated negative binomial model created county-level predictions of the probability of rabies freedom and the expected number of rabies cases reported. Data analyzed were from all animals submitted for laboratory diagnosis of rabies in the United States from 1995 to 2020 in skunk and raccoon reservoir territories, excluding bats and bat variants.

RESULTS

We analyzed data from 14,642 and 30,120 county-years in the raccoon and skunk reservoir territories, respectively. Only 0.85% (9/1065) raccoon county-years and 0.79% (27/3411) skunk county-years that met the historical rabies-free criteria reported a case in the following year (99.2% negative predictive value for each), of which 2 were attributed to unreported bat variants. County-level model predictions displayed excellent discrimination for detecting zero cases and good estimates of reported cases in the following year. Counties classified as rabies free rarely (36/4476, 0.8%) detected cases in the following year.

CONCLUSIONS

This study concludes that the historical rabies freedom definition is a reasonable approach for identifying counties that are truly free from terrestrial raccoon and skunk rabies virus transmission. Gradations of risk can be measured using the rabies prediction model presented in this study. However, even counties with a high probability of rabies freedom should maintain rabies testing capacity, as there are numerous examples of translocations of rabies-infected animals that can cause major changes in the epidemiology of rabies.

Nonarboviral Equine Encephalitides

Several viruses transmitted by biological vectors or through direct contact, air, or ingestion cause neurologic disease in equids. Of interest are viruses of the Togaviridae, Flaviviridae, Rhabdoviridae, Herpesviridae, Bornaviridae, and Bunyaviridae families. Variable degree of inflammation is present with these viruses but lack of an inflammatory response does not rule out their presence. The goal of this article is to provide an overview on pathophysiologic and clinical aspects of nonarboviral equine encephalitides, specifically on lyssaviruses (rabies) and bornaviruses (Borna disease).

Use of a Modified Preexposure Prophylaxis Vaccination Schedule to Prevent Human Rabies: Recommendations of the Advisory Committee on Immunization Practices - United States, 2022

Human rabies is an acute, progressive encephalomyelitis that is nearly always fatal once symptoms begin. Several measures have been implemented to prevent human rabies in the United States, including vaccination of targeted domesticated and wild animals, avoidance of behaviors that might precipitate an exposure (e.g., provoking high-risk animals), awareness of the types of animal contact that require postexposure prophylaxis (PEP), and use of proper personal protective equipment when handling animals or laboratory specimens. PEP is widely available in the United States and highly effective if administered after an exposure occurs. A small subset of persons has a higher level of risk for being exposed to rabies virus than does the general U.S. population; these persons are recommended to receive preexposure prophylaxis (PrEP), a series of human rabies vaccine doses administered before an exposure occurs, in addition to PEP after an exposure. PrEP does not eliminate the need for PEP; however, it does simplify the rabies PEP schedule (i.e., eliminates the need for rabies immunoglobulin and decreases the number of vaccine doses required for PEP). As rabies epidemiology has evolved and vaccine safety and efficacy have improved, Advisory Committee on Immunization Practices (ACIP) recommendations to prevent human rabies have changed. During September 2019-November 2021, the ACIP Rabies Work Group considered updates to the 2008 ACIP recommendations by evaluating newly published data, reviewing frequently asked questions, and identifying barriers to adherence to previous ACIP rabies vaccination recommendations. Topics were presented and discussed during six ACIP meetings. The following modifications to PrEP are summarized in this report: 1) redefined risk categories; 2) fewer vaccine doses in the primary vaccination schedule; 3) flexible options for ensuring long-term protection, or immunogenicity; 4) less frequent or no antibody titer checks for some risk groups; 5) a new minimum rabies antibody titer (0.5 international units [IUs]) per mL); and 6) clinical guidance, including for ensuring effective vaccination of certain special populations.

Rabies surveillance in the United States during 2020

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 in the Tropics

Purpose of Review

Rabies is an ancient yet still neglected tropical disease (NTD). This review focuses upon highlights of recent research and peer-reviewed communications on the underestimated tropical burden of disease and its management due to the complicated dynamics of virulent viral species, diverse mammalian reservoirs, and tens of millions of exposed humans and animals - and how laboratory-based surveillance at each level informs upon pathogen spread and risks of transmission, for targeted prevention and control.

Recent Findings

While both human and rabies animal cases in enzootic areas over the past 5 years were reported to PAHO/WHO and OIE by member countries, still there is a huge gap between these "official" data and the need for enhanced surveillance efforts to meet global program goals.

Summary

A review of the complex aspects of rabies perpetuation in human, domestic animal, and wildlife communities, coupled with a high fatality rate despite the existence of efficacious biologics (but no therapeutics), warrants the need for a One Health approach toward detection via improved laboratory-based surveillance, with focal management at the viral source. More effective methods to prevent the spread of rabies from enzootic to free zones are needed.

Assessing the extent and public health impact of bat predation by domestic animals using data from a rabies passive surveillance program

Domestic animals can serve as consequential conveyors of zoonotic pathogens across wildlife-human interfaces. Still, there has been little study on how different domestic species and their behaviors influence the zoonotic risk to humans. In this study, we examined patterns of bat encounters with domestic animals that resulted in submission for testing at the rabies laboratories of the Canadian Food Inspection Agency (CFIA) during 2014-2020. Our goals were specifically to examine how the number of bats submitted and the number of rabies positive bats varied by the type of domestic animal exposure and whether domestic cats were indoor or free-roaming. The CFIA reported 6258 bat submissions for rabies testing, of which 41.5% and 8.7% had encounter histories with cats and dogs, respectively. A much smaller fraction of bat submissions (0.3%) had exposure to other domestic animals, and 49.5% had no domestic animal exposure. For the bat submissions related to cats, and where lifestyle was noted, 91.1% were associated with free-roaming cats and 8.9% with indoor cats. Model results indicated the probability of a rabies-positive bat was the highest with a history of dog association (20.2%), followed by bats with no animal exposure (16.7%), free-roaming cats (6.9%), cats with unspecified histories (6.0%) and the lowest probability associated with non-free-roaming (indoor) cats (3.8%). Although there was lower rabies prevalence in bats associated with cats compared to dogs, the 4.8 fold higher number of cat-bat interactions cumulatively leads to a greater overall rabies exposure risk to humans from any free-roaming outdoor cats. This study suggests that free-roaming owned cats may have an underappreciated role in cryptic rabies exposures in humans and as a significant predator of bats. Preventing free-roaming in cats is a cost-effective and underutilized public health recommendation for rabies prevention that also synergistically reduces the health burden of other feline-associated zoonotic diseases and promotes feline welfare and wildlife conservation.