Annual rabies report

Utah Department of Health and Human Services

2024

Background

Rabies is a preventable viral disease that affects the brain and spinal cord of mammals. It is most often transmitted through the bite of an infected animal. In the US, wildlife is the main reservoir of rabies. In Utah, all rabies testing for animals is performed at the Utah Public Health Laboratory (UPHL). Animals suspected of having rabies, or that have exposed a human or domestic animal, are prioritized for testing. Over the past 5 years (2019–2023), an average of 16 animals tested positive for rabies each year. Most of these animals were bats, which are the main wildlife reservoir of rabies in Utah. Because human rabies is nearly always fatal once symptoms appear, it is critical to report all possible rabies exposures to public health to ensure life-saving treatment is provided when necessary. No human cases of rabies have been reported in the state since 2018; however, an average of 1–2 cases are reported in the US every year.

Introduction

In 2024, 484 animals were submitted for rabies testing. Of those submissions, 31 were positive, 404 were negative, and 49 could not be tested because of poor specimen quality. All 31 rabid animals were bats. This is the highest known number of positive rabies detections reported in a single year. A total of 228 bats were tested for rabies virus, resulting in a 13.6% test positivity rate.

These 31 rabid bats resulted in 13 people and 13 pets being exposed to rabies. Positive bats were identified across the state in Cache (2), Davis (3), Grand (3), Iron (1), Kane (2), Salt Lake (6), Sanpete (2), Wasatch (1), Washington (5), Wayne (1), and Weber (5) counties.

Weekly rabies activity

Most rabid animals in Utah are detected during the months of June–October. In 2024, the first and last rabid animal detections were a little earlier than average, on May 17 and October 4, respectively. Figure 1 shows the number of rabid animals detected each week in 2024 compared to the average number of detections for that week over the past 5 years (2019–2023).

Figure 1. Epidemiological curve, 2024 vs. 5 year average

Summary of rabies testing by local health jurisdiction

In Utah, there are 13 local health jurisdictions. In 2024, specimens were submitted from every health jurisdiction. Table 1 shows the total number of specimens tested from each health jurisdiction and a breakdown of results. Salt Lake County submitted the most specimens for testing. Figure 2 shows where the positive animals were found. Southwest Utah had the largest number of rabid animals detected (8). No rabid animals were detected in San Juan, Summit County, Tooele County, TriCounty, or in Utah County, despite submitting specimens for testing.

Table 1. Positive, negative, and unsatisfactory results by local health jurisdiction, 2024

Jurisdiction Positive Negative Unsatisfactory Total
Bear River (Cache, Rich, and Box Elder counties) 2 23 5 30
Central Utah (Juab, Millard, Piute, Sanpete, Sevier, and Wayne counties) 3 5 1 9
Davis County 3 35 2 40
Salt Lake County 6 172 9 187
San Juan 0 1 1 2
Southeast Utah (Carbon, Emery, and Grand counties) 3 6 2 11
Southwest Utah (Beaver, Garfield, Iron, Kane, and Washington counties) 8 35 12 55
Summit County 0 10 4 14
Tooele County 0 2 0 2
TriCounty (Daggett, Duchesne, and Uintah counties) 0 4 2 6
Utah County 0 59 6 65
Wasatch County 1 7 0 8
Weber-Morgan (Weber and Morgan counties) 5 40 5 50
Unknown 0 5 0 5
Total 31 404 49 484

Figure 2. Map of rabid animal detections by local health jurisdiction, 2024

Species of animals tested at UPHL

All specimens that tested positive for rabies in 2024 were bats. A breakdown by species is shown below in Table 2. Note that Myotis bats were not identified past the genus level. As such, there were more Myotis bats tested than any other species. Mexican Free-tailed bats made up the largest share of rabid bats.

Table 2. Rabid bats by species, 2024

Bat species Positive Total tested Percent positivity
Big Brown 7 33 21.2%
Big Free-tailed 0 2 0.0%
Hoary 1 1 100.0%
Mexican Free-tailed 10 59 16.9%
Myotis 5 67 7.5%
Pallid 1 7 14.3%
Silver-haired 1 23 4.3%
Townsend’s Big Ear 0 1 0.0%
Western Pipistrelle 6 11 54.5%
Western Red Bat 0 6 0.0%
Unknown 0 18 0.0%

Any animal that exposes a person or pet or is suspected of having rabies is tested for rabies at UPHL. Table 3 provides a list of all species submitted for testing in 2024. Nearly half (47.1%) of all animals submitted were bats. Cats and dogs combined also made up a large proportion of animals submitted (41.5%).

Table 3. Species of all animals submitted for testing, 2024

Animal type Total tested Percent
Badger 1 0.2%
Bat 228 47.1%
Bear 1 0.2%
Cat 78 16.1%
Dog 123 25.4%
Ferret 1 0.2%
Fox 1 0.2%
Gopher 1 0.2%
Mink 2 0.4%
Mouse 1 0.2%
Raccoon 38 7.9%
Skunk 5 1.0%
Squirrel 4 0.8%