At a glance
In 2021, health departments reported 273 cases of botulism to ÐÇ¿ÕÓéÀÖ¹ÙÍø. Of those, 243 cases were laboratory-confirmed and 30 were probable (Table 1). The cases were of the following types: 181 (66%) infant, 66 (24%) wound, 22 (8%) foodborne, and 4 (1%) other.
Infant botulism cases
Health departments reported 181 laboratory-confirmed cases of infant botulism (Table 1). Cases were reported from 31 states, with California (45 cases, 25%) and Pennsylvania (21, 12%) reporting the most. The toxin types were A (72, 40%), B (107, 59%), Ba (1, <1%), and Bf (1, <1%).
Type Bf infant botulism is rare; only 19 U.S. cases have been previously reported (8 from Texas, 7 California, 1 Maryland, 1 New Jersey, 1 New Mexico, 1 New York). The type Bf case in 2021 was identified in Texas. Type Ba infant botulism is even more uncommon; only 9 cases have been previously reported in the United States (5 from California and 1 each from Illinois, Nevada, New York, and Texas). The type Ba case in 2021 was identified in California. Toxin types Ba and Bf indicate bivalent strains, which means one strain can produce two types of toxin. The capital letter indicates the most abundant toxin type.
This year marks the highest annual case count of infant botulism since it was first characterized in 1976. The years with the next-highest case counts for infant botulism are 2018 (163 cases) and 2020 (159 cases). The median age of infants was 3 months; 91 (50%) were male and 90 (50%) were female. No deaths were reported.
Wound botulism cases
Health departments reported 66 cases of wound botulism, including 40 laboratory-confirmed and 26 probable (Table 1).
The 40 cases of laboratory-confirmed wound botulism were reported from 9 states: California (26 cases, 65%), New Mexico (5, 13%), Oregon (3, 8%), Colorado (1, 3%), Kentucky (1, 3%), Maryland (1, 3%), Nevada (1, 3%), Ohio (1, 3%), and Texas (1, 3%) (Table 1).
Among the 24 cases with exposure information available, all (100%) patients reported injection drug use, and of those, 10 (42%) reported using black tar heroin.
Most cases were caused by toxin type A (29, 73%) or B (6, 15%). In 5 (13%) cases, botulinum toxin was detected but a specific serotype could not be determined; toxin type for these cases is listed as ABE in Tables 1 and 2. The median age of patients was 45 years (range: 26–65); 27 (68%) were male and 13 (33%) were female. Two (2, 5%) deaths were reported.
The 26 cases of probable wound botulism were reported from California (25, 96%) and Texas (1, 4%). All (100%) occurred in persons who injected drugs; 8 (80%) reported black tar heroin use. The median age of cases was 56 years (range: 24–70); 20 (77%) were male and 6 (23%) were female. No deaths were reported.
Four probable cases were part of 2 separate outbreaks:
- California reported an outbreak of 2 probable cases in February linked to injection drug use.
- California reported an outbreak of 2 probable cases in March linked to injection heroin use.
Foodborne botulism cases
Health departments reported 22 cases of foodborne botulism: 18 (82%) were laboratory-confirmed and 4 (18%) were probable (Table 1). Of the 18 laboratory-confirmed cases, 14 (78%) were caused by type A and 4 (22%) were type E.
The 18 cases of laboratory-confirmed foodborne botulism were reported from ten states; Alaska reported the most (4 cases). Confirmed or suspected foods linked to cases are described in Table 2. Eight confirmed cases were part of outbreaks:
- Alaska reported a type E outbreak of 2 cases linked to home-prepared seal oil.
- Alaska reported a type E outbreak of 2 cases linked to fermented beluga whale.
- Florida reported a type A outbreak of 2 cases linked to an unknown source.
- Georgia reported a type A outbreak of 2 cases linked to home-canned potatoes and sausages.
The median age of patients with laboratory-confirmed foodborne botulism was 57 years (range: 22–77); 11 (61%) were male and 7 (39%) were female. Two deaths were reported.
Four probable foodborne botulism cases were reported. Two cases were reported from Alaska; one with a suspected link to seal oil and the other to "stink heads", a traditional Alaska native dish consisting of fish heads fermented in the ground. Hawaii and Massachusetts reported one case each, but a specific food exposure was not identified for either case. No deaths were reported.
Other cases of botulism
Health departments reported 4 cases of botulism of other or unknown etiology from 4 states. The median age of cases was 58 years (range: 10–74) and 1 case (25%) was male; the remainder (3, 75%) were female. By toxin type, 3 (75%) were caused by type A and 1 (25%) by type F.
One case reported from Minnesota was suspected to be adult intestinal botulism, a rare form of botulism thought to have a mechanism similar to that of infant botulism.
No definitive route of transmission was identified for the other 3 cases, in which the patients did not consume a suspect food, have any wounds, or have any known risk factors for adult intestinal colonization. Two deaths were reported.
Tables
| Transmission Category | Cases | Median Age (range) |
Deaths | Sex, n (%) | Toxin Type, n (%) | Outbreaks* |
|---|---|---|---|---|---|---|
| Infant | 181 | 3 months (12 days – 11 months) | 0 | Male: 91 (50); Female: 90 (50) |
A: 72 (40), B: 107 (59), Ba: 1 (<1), Bf: 1 (<1) |
0 |
| Wound | 40 | 45 (26–65) years | 2 | Male: 27 (68); Female: 13 (33) |
A: 29 (73), B: 6 (15), ABE: 5 (13) |
0 |
| Foodborne | 18 | 57 (22–77) years | 2 | Male: 11 (61); Female: 7 (39) |
A: 14 (78), E: 4 (22) |
4 |
| Other |
4 | 58 (10–74) years | 2 | Male: 1 (25); Female: 3 (75) |
A: 3 (75), F: 1 (25) |
0 |
| Transmission Category | Cases | Median Age (range) |
Deaths | Sex, n (%) | Toxin Type, n (%) | Outbreaks* |
|---|---|---|---|---|---|---|
| Wound¶ | 26 | 56 (24–70) years | 0 | Male: 20 (77); Female: 6 (23) |
Not applicable | 2 |
| Foodborne‡ | 4 | 54 (39–67) years | 0 | Male: 1 (25); Female: 3 (75) |
Not applicable | 0 |
*Outbreak defined as two or more cases resulting from a common exposure.
¶Probable wound botulism is defined as a clinically compatible case with no suspected exposure to contaminated food and with a history in the 2 weeks before illness began of either a fresh contaminated wound or injection drug use.
‡Probable foodborne botulism is defined as a clinically compatible case with an epidemiologic link (e.g., ingestion of a home-canned food within the previous 48 hours).
| Month | State | Confirmed or Suspected Food | Toxin Type | Cases |
|---|---|---|---|---|
| January | Alaska | Seal oil | E | 2 |
| January | Kentucky | Improperly stored clam chowder | A | 1 |
| March | Arizona | Home-canned beans | A | 1 |
| May | Florida | Unknown | A | 2 |
| June | Alaska | Fermented beluga whale | E | 2 |
| June | Georgia | Unknown | A | 1 |
| August | Maine | Unknown | A | 1 |
| September | California | Unknown | A | 1 |
| September | Colorado | Unknown | A | 1 |
| September | South Carolina | Home-canned meat* | A | 1 |
| September | Wisconsin | Unknown | A | 1 |
| November | Arizona | Commercially canned soup (packaging defect)* | A | 1 |
| November | Florida | Home-canned potatoes | A | 1 |
| December | Georgia | Home-canned potatoes and sausages* | A | 2 |
*Foods followed by an asterisk were confirmed as the source by detection of toxin in food. In foods without an asterisk, toxin was not detected, or food item was not available for testing; food vehicle was suspected based on clinical history, epidemiologic evidence, or reported method of preparation or storage.