Volume 29, Number 9—September 2023
CME ACTIVITY - Synopsis
Characteristics of Hard Tick Relapsing Fever Caused by Borrelia miyamotoi, United States, 2013–2019
Table 2
Clinical and laboratory findings for persons who have confirmed and possible hard tick relapsing fever caused by Borrelia miyamotoi identified by public health surveillance, United States, 2013–2019*
Characteristic | Confirmed, n = 165 | Possible, n = 133 | p value |
---|---|---|---|
Hospitalized |
20 (12) |
19 (14) |
0.61 |
Median duration of illness, d† (IQR) |
3 (2–7) |
9 (3–29) |
0.03 |
Required symptoms | |||
Fever | 157 (95) | 108 (81) | <0.0001 |
Chills |
115 (70) |
87 (65) |
0.27 |
Supporting signs and symptoms | |||
Headache | 118 (72) | 96 (72) | 0.85 |
Myalgia | 104 (63) | 94 (71) | 0.20 |
Arthralgia | 79 (48) | 84 (63) | 0.02 |
Malaise/fatigue | 125 (76) | 99 (74) | 0.55 |
Rash | 21 (13) | 28 (21) | 0.06 |
Abdominal pain | 16 (10) | 27 (20) | 0.01 |
Nausea | 55 (33) | 36 (27) | 0.26 |
Vomiting | 23 (14) | 15 (11) | 0.44 |
Diarrhea | 8 (5) | 17 (13) | 0.01 |
Dizziness | 26 (16) | 33 (25) | 0.06 |
Confusion | 7 (4) | 24 (18) | <0.0001 |
Photophobia | 8 (5) | 11 (8) | 0.29 |
Leukopenia‡ | 31 (46) | 8 (22) | 0.02 |
Thrombocytopenia§ | 40 (58) | 9 (25) | 0.001 |
Increased levels of aminotransferases¶ |
27 (45) |
13 (36) |
0.41 |
Other symptoms | |||
Recurring fevers | 37 (22) | 47 (35) | 0.01 |
Shortness of breath | 5 (3) | 14 (11) | 0.01 |
Cough | 15 (9) | 10 (8) | 0.53 |
Anorexia | 32 (19) | 26 (20) | 0.99 |
Jaundice | 2 (1) | 4 (3) | 0.21 |
Lymphadenopathy | 0 (0) | 0 (0) | NA |
Cognitive impairment/mood disturbance | 7 (4) | 21 (16) | 0.0004 |
Meningitis/encephalitis | 0 (0) | 5 (4) | 0.01 |
Neutropenia | 6 (4) | 2 (2) | 0.11 |
Abnormal chest radiograph | 11 (7) | 2 (2) | 0.04 |
*Values are no. (%) unless indicated otherwise. IQR, interquartile range; NA, not available. †Defined as duration from symptom onset to first seeking medical care. ‡Information regarding a patient’s leukocyte count was available for 68 confirmed and 37 possible cases. §Information regarding a patient’s platelet count was available for 69 confirmed and 36 possible cases. ¶Information regarding a patient’s alanine and aspartate aminotransferase levels was available for 60 confirmed and 36 possible cases.