Pandemic impacts to rabies surveillance, prevention, and control?

I thank our colleagues at the CDC and USDA and in Canada and Mexico for their thorough 2020 surveillance report on rabies.¹ Ideally, considering technical advances and online reporting, time to publication after data analysis should decrease in the future for maximum utility to JAVMA readers. Moreover, given the porosity of borders and critical need for international collaborations, perhaps the authors might consider an alteration to the title, with greater inclusivity toward additional North American data, from a continental perspective? Within a larger regional context, the impact of the current COVID-19 pandemic on surveillance for zoonoses is worrisome. Submissions of suspect rabid animals declined.¹ One interpretation is that fewer persons and domestic animals were exposed due to movement restrictions and testing limitations. Nevertheless, this should not be misinterpreted that rabies is less significant as a fundamental disease of nature. Besides domestic species, enhanced laboratory-based surveillance of wildlife is a necessity for an improved epidemiological appreciation toward robust disease prevention and control.² Moreover, with the elimination of canine rabies virus transmission within North America, there is an even greater need for timely rabies virus characterization at a local level, augmented by national support to minimize risks associated with dog importations.³ As such, submitting veterinarians should engage their local public health authorities on a thorough investigation of all rabid domestic animals. While no human rabies was reported in the US during 2019 to 2020, at least 5 human rabies cases were detected in 2021, 4 from indigenous bat exposures and 1 acquired abroad from a rabid dog.¹ While all these fatalities were preventable in theory, once again the repercussions from the pandemic may have been operative. In Illinois, in the first reported human rabies case in the state since 1954, exposure was recognized and the bat was confirmed rabid. Vaccine hesitancy seemed at play, but specific details on patient education, outreach, and interventions were lacking.^1,4 Similarly, an 84-year-old immunocompromised male, exposed to a rabid bat in Minnesota and administered postexposure prophylaxis (PEP), died nonetheless as an apparent breakthrough infection during January 2021 but seems to have garnered the least attention, despite unprecedented significance.^1,5 Globally, most human rabies deaths occur because of no or inappropriate PEP. Human deaths after timely and appropriate PEP are rare. No such US human cases were reported since the advent of modern biologics during the 1970s, despite thousands of annual exposures, which should prompt thorough investigation and communication.^1,6

Charles E. Rupprecht, VMD, PhD

Auburn, Alabama

The authors respond:

The authors thank Dr. Rupprecht for his comments regarding our 2020 rabies surveillance report. The US National Rabies Surveillance System is a laboratory-based system comprised of approximately 130 public health, agriculture, and academic laboratories that conduct animal rabies testing as well as 54 state, district, and territorial public health jurisdictions that conduct epidemiological investigations. With support from JAVMA and technical advances in reporting, we’ll continue our efforts to make national rabies surveillance information publicly available as quickly as possible, as the CDC has for the past 30 years.¹

The US and its North American neighbors have developed robust public health systems to identify, respond to, and diagnose rabies in animals and humans, as was recently highlighted by Mexico’s designation as free from dog-mediated human rabies deaths.² Rabies epidemiology in the US is diverse in terms of ecosystems and reservoir species. Health programs and USDA Wildlife Services test nearly 100,000 animals each year, and the Wildlife Services has extensive cooperative management programs to prevent the further spread and eliminate certain viral variants at the local and regional levels. It would be difficult to adequately describe these extensive actions and impacts of rabies control efforts across Mexico, the US, and Canada in 1 publication. The North American Rabies Management Plan is a formalized entity that includes these 3 countries and convenes regularly to collaborate on rabies management and surveillance activities. A recurring publication from the North American Rabies Management Plan would be an ideal forum to disseminate information on continental rabies.

Characterization of rabies viruses provides important insight into epidemiological changes and informs wildlife rabies management actions. However, characterization presents an added cost to public health programs, which is not fiscally possible for all jurisdictions and may not be necessary when regional and national capacity is easily accessible. To ensure that viral characterization is conducted on samples that are most likely to impact human and animal health, a 2-part publication was released in 2019 that defines “samples of epidemiological importance” (SEI) and provides guidance on samples to prioritize for viral characterization.³ The National Rabies Surveillance System now tracks SEI characterization rates and works with jurisdictions to provide characterization assistance. In 2020, 40% of SEI in the US were characterized.¹ This rate shows room for improvement but also a significant and coordinated effort by local and federal agencies.

During the COVID-19 pandemic, many came to the unfortunate realization that public health data systems, overall, are antiquated and contribute to delays in data sharing, interpretation, and dissemination.⁴ While rabies control infrastructure in the US is among the best in the world, data systems are not fully supported for real-time data and information sharing, resulting in delays for data sharing between local, state, and federal agencies. We are hopeful that the American Rescue Plan’s Data Modernization Initiative will help improve support for rabies data systems to address concerns raised by Dr. Rupprecht regarding laboratory-based surveillance to improve the epidemiological understanding of rabies in North America. These concerns are shared by many in the North American rabies community.

Lastly, we cannot assume that lack of publication on human rabies cases and other notable events implies that public health due diligence was not conducted. Several of the cases highlighted in the Letter to the Editor were thoroughly investigated by multiple agencies. Publications providing further detail on these events are under peer review; however, there is a notable global delay in journal publication times. Further, it is not uncommon for subjects or their families to disapprove of publishing case reports of which they are the subject. While it may not be possible to publish all notable rabies prevention and control work conducted in the US each year, state and federal agencies prioritize dissemination of impactful public and animal health communications.

Xiaoyue Ma, MPH

Ryan M. Wallace, DVM

Sarah Bonaparte, MPH

Lillian A. Orciari, MS

Agam K. Rao, MD

Poxvirus and Rabies Branch

Division of High-Consequence Pathogens and Pathology

National Center for Emerging and Zoonotic Infectious Diseases

CDC

Atlanta, Georgia

Jordona D. Kirby, MS

Richard B. Chipman, MS

Wildlife Services

APHIS, USDA

Concord, New Hampshire

Christine Fehlner-Gardiner, PhD

Centre of Expertise for Rabies

Ottawa Laboratory–Fallowfield

Canadian Food Inspection Agency

Ottawa, Canada

Nidia Aréchiga-Ceballos, PhD

Laboratorio de Rabia

Departamento de Virología

Instituto de Diagnóstico y Referencia Epidemiológicos

Ciudad de México, México