Background
Methods
Volunteers and study design
Questionnaires
Definitions
Destinations
Number | (%a) | |
---|---|---|
Sex (missing data = 0) | ||
Male | 173 | (38) |
Female | 287 | (62) |
Age, median (IQR) (missing data = 0) | 35 (27.0–54.0) | |
0–17, children | 35 | (8) |
18–35, young adults | 196 | (43) |
36–55, middle aged | 120 | (26) |
56–, older travelers | 109 | (24) |
Underlying diseases (missing data = 0) | 192 | (42) |
Asthma, atopy and/or allergy | 56 | (12) |
Hypertension | 51 | (11) |
Psychiatric disorder or medication | 25 | (5) |
Cardiovascular disease | 14 | (3) |
GI disorder b | 13 | (3) |
Neurological disorder | 12 | (3) |
DM | 9 | (2) |
Rheumatic disease | 6 | (1) |
Other disease and conditions | 78 | (17) |
Contraceptives or postmenopausal hormone replacement therapy | 53 | (12) |
Duration of travel, median in days (IQR) (missing data = 2) | 16 (12.8–27.3) | |
1 week or less (missing data = 0) | 27 | (6) |
More than a week and less than a month | 334 | (73) |
1–5 months | 99 | (22) |
Purpose of travel (missing data = 1) | ||
Vacation | 383 | (83) |
Business | 38 | (8) |
Other/multiple c | 38 | (8) |
Geographic region (missing data = 0) d | ||
South-Eastern Asia | 107 | (23) |
Eastern Africa | 96 | (21) |
Western Africa, Middle Africa | 86 | (19) |
Southern Asia | 68 | (15) |
Latin America and the Caribbean | 41 | (9) |
Southern Africa | 26 | (6) |
Europe, Northern America | 15 | (3) |
Northern Africa, Western Asia | 12 | (3) |
Eastern Asia, Central Asia | 9 | (2) |
Statistics
Results
Cohort population and prophylactic measures
Protected before consultation, N (%a) | Vaccinated at consultation, N (%a) | Protected according to recommendations given for the region visited, N (%a) | |
---|---|---|---|
Tetanus (missing data = 4) | 353 (77) | 96 (21) | 449 (98) |
MMR (missing data = 43) | 393 (94) | 21 (5) | 414 (99) |
Hepatitis A (missing data = 3) | 325 (71) | 130 (28) | 440 (100) |
Hepatitis B (missing data = 4) | 178 (39) | 124 (27) | 72 (73) |
Yellow Fever (missing data = 2) | 112 (24) | 153 (33) | 182 (96) |
Polio (missing data = 4) b | 140 (31) | 84 (18) | 104 (63) |
Typhoid fever (missing data = 3) | 38 (8) | 63 (14) | 47 (65) |
oral | 16 (4) | 59 (13) | |
injected | 22 (5) | 4 (1) | |
Japanese encephalitis (missing data = 3) c | 15 (3) | 30 (7) | 18 (53) |
Other (missing data = 3) d | 14 (3) | 58 (13) |
Number | (%a) | |
---|---|---|
Prophylactic antimalarial use among those recommended (missing data = 6) | 289 | (98) |
Atovaquone and proguanil | 135 | (30) |
Mefloquine | 70 | (15) |
Doxycycline | 55 | (12) |
Chloroquine | 25 | (6) |
Other / not known | 2 | (0) |
Changed drug b | 2 | (0) |
Failure in use c | 7 | (2) |
Antimicrobials (other than doxicycline) (missing data = 0) d | 81 | (18) |
Fluoroquinolone | 53 | (12) |
Macrolide | 9 | (2) |
Nitroimidazole (metronidazole or tinidatzole) | 7 | (2) |
Amoxicillin | 5 | (1) |
Tetracycline | 1 | (0) |
Other / not known | 25 | (5) |
Two or more antimicrobials (without doxycycline) | 15 | (3) |
Treatment for malaria (missing data = 0) e | 4 | (1) |
Gastrointestinal medication (missing data = 0) | 127 | (28) |
Loperamide | 115 | (25) |
Medicinal charcoal | 7 | (2) |
Other (laxative, spasmolyte, co-phenotrope) | 10 | (2) |
Two or more gastrointestinal medications | 5 | (1) |
Analgesic (missing data = 0) | 123 | (27) |
NSAID | 67 | (15) |
Paracetamol | 59 | (13) |
Other / not known | 16 | (3) |
Two or more analgesics | 18 | (4) |
Antiemetic (missing data = 0) | 4 | (1) |
PPI or antacid (missing data = 4) | 36 | (8) |
PPI | 26 | (6) |
Antacid (salts/H2) | 10 | (2) |
Probiotics and prebiotics (missing data = 3) f | 270 | (59) |
Starting before travel | 11 | (2) |
Using only during travel | 123 | (27) |
Starting before and using during travel | 136 | (30) |
Travel information and behavior
Number (%) | Destination % | Sex % | Age group (years) % | Duration of travel (days) % | Purpose of travel % | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Africa | Asia | other | p-value | male | female | p-value | 0–17 | 18–35 | 36–55 | 56– | p-value | 1–7 | 8–29 | 30–160 | p-value | vacation | business | other | p-value | ||
Age group (missing data = 0) | <0.001* | 0.833 | <0.001* | 0.056 | |||||||||||||||||
0–17 | 35 (8) | 8 | 7 | 11 | 8 | 7 | 30 | 7 | 3 | 9 | 0 | 3 | |||||||||
18–35 | 196 (43) |
32
|
55
|
41
|
43
|
42
| 22 |
36
|
72
|
42
| 37 |
61
| |||||||||
36–55 | 120 (26) | 30 | 23 | 23 | 27 | 25 |
33
| 29 | 13 | 26 |
39
| 16 | |||||||||
56– | 109 (24) | 31 | 15 | 25 | 21 | 25 | 15 | 28 | 12 | 24 | 24 | 21 | |||||||||
Duration of travel, days (missing data = 0) | <0.001* | 0.473 | <0.001* | <0.001d* | |||||||||||||||||
1–7 | 27 (6) | 2 | 6 | 20 | 7 | 5 | 23 | 3 | 8 | 4 | 6 | 13 | 0 | ||||||||
8–29 | 334 (73) |
81
|
63
|
73
|
72
|
73
|
69
|
61
|
82
|
85
|
79
|
53
| 29 | ||||||||
30–160 | 99 (22) | 17 | 31 | 7 | 20 | 22 | 9 | 36 | 11 | 11 | 15 | 34 |
71
| ||||||||
Purpose of travel (missing data = 1) a | 0.034d* | 0.002* | 0.056 | <0.001d* | |||||||||||||||||
vacation | 383 (84) |
78
|
88
|
91
|
86
|
82
|
97
|
81
|
83
|
84
|
81
|
91
|
60
| ||||||||
business | 37 (8) | 12 | 5 | 4 | 11 | 7 | 0 | 7 | 13 | 8 | 19 | 6 | 13 | ||||||||
other/multiple | 35 (8) | 10 | 7 | 5 | 3 | 11 | 3 | 12 | 5 | 7 | 0 | 3 | 27 | ||||||||
Accommodation (missing data = 11) b | <0.001* | 0.008* | <0.001* | <0.001* | <0.001* | ||||||||||||||||
hotel | 188 (42) |
39
| 40 |
61
|
46
|
40
| 34 | 31 |
50
|
55
|
85
|
46
| 15 |
44
|
45
| 18 | |||||
home of a local | 71 (16) | 23 | 9 | 14 | 9 | 20 | 26 | 16 | 11 | 17 | 15 | 12 | 29 | 12 | 16 |
50
| |||||
guest house | 190 (42) |
39
|
52
| 25 | 45 | 41 |
40
|
53
| 39 | 28 | 0 | 42 |
56
|
44
| 39 | 32 | |||||
Location (missing data = 22) b | <0.001* | 0.083 | 0.088 | <0.001* | 0.494 | ||||||||||||||||
city | 143 (33) | 24 | 34 |
57
| 28 | 36 | 44 | 27 | 36 | 38 |
88
| 31 | 23 | 33 | 38 | 25 | |||||
countryside/jungle | 295 (67) |
76
|
66
| 43 |
72
|
64
|
56
|
73
|
66
|
62
| 12 |
69
|
77
|
67
|
62
|
75
| |||||
Used other than bottled water (missing data = 3) b | 25 (5) | 8 | 3 | 5 | 0.144 | 6 | 5 | 0.499 | 3 | 4 | 8 | 6 | 0.373 | 0 | 5 | 7 | 0.336 | 5 | 11 | 5 | 0.379d |
Ate uncooked meat/fish (missing data = 4) | 58 (13) | 9 | 16 | 18 | 0.045* | 11 | 14 | 0.446 | 6 | 17 | 13 | 6 | 0.016* | 4 | 12 | 18 | 0.080 | 13 | 13 | 11 | 0.961d |
Ate salads (missing data = 26) | 341 (79) | 77 | 78 | 85 | 0.427 | 79 | 78 | 0.904 | 59 | 83 | 81 | 74 | 0.009* | 69 | 78 | 83 | 0.288 | 80 | 70 | 78 | 0.404 |
Diet (missing data = 159) | 0.087 | 0.018* | 0.010* | 0.288 | 1.000d | ||||||||||||||||
omnivore | 274 (91) |
92
|
88
| 100 |
96
|
88
|
100
|
85
|
92
|
97
|
100
|
92
|
88
|
91
|
91
|
93
| |||||
vegetarian | 27 (9) | 8 | 12 | 0 | 4 | 12 | 0 | 15 | 8 | 3 | 0 | 8 | 13 | 9 | 9 | 7 | |||||
Used milk as part of diet (missing data = 161) | 293 (98) | 99 | 97 | 96 | 0.226d | 99 | 97 | 0.426d | 96 | 98 | 99 | 97 | 0.599d | 100 | 99 | 96 | 0.347d | 98 | 100 | 100 | 1.000d |
Site of meals (missing data = 12) b | <0.001* | 0.099 | <0.001* | 0.660 | 0.042* | ||||||||||||||||
restaurant more than 50 % | 372 (83) |
70
|
96
|
87
|
87
|
81
|
53
|
86
|
86
|
83
|
89
|
83
|
81
|
84
|
83
|
68
| |||||
own household and sometimes elsewhere | 76 (17) | 30 | 4 | 13 | 13 | 19 | 47 | 14 | 14 | 17 | 11 | 17 | 19 | 16 | 17 | 32 | |||||
Alcohol consumption (missing data = 67) c | 0.112 | <0.001* | 0.001* | 0.117 | 0.025* | ||||||||||||||||
0–2 units per day | 281 (61) |
72
|
74
|
59
|
61
|
78
|
100
|
70
|
64
|
71
|
65
|
69
|
80
|
70
|
64
|
91
| |||||
3– units per day | 112 (24) | 28 | 26 | 41 | 39 | 22 | 0 | 30 | 36 | 29 | 35 | 31 | 20 | 30 | 36 | 9 | |||||
Did not always use utensils (missing data = 23) | 126 (29) | 28 | 34 | 18 | 0.070 | 28 | 29 | 0.877 | 39 | 40 | 24 | 10 | <0.001* | 17 | 22 | 55 | <0.001* | 26 | 39 | 49 | 0.004* |
Did not wash hands always/often (missing data = 13) | 61 (14) | 10 | 16 | 18 | 0.147 | 17 | 12 | 0.138 | 9 | 21 | 9 | 7 | 0.001* | 11 | 13 | 17 | 0.573 | 14 | 14 | 11 | 0.840 |
No WC as a toilet (missing data = 7) | 74 (16) | 22 | 13 | 5 | 0.004* | 17 | 16 | 0.747 | 16 | 19 | 18 | 10 | 0.235 | 0 | 16 | 21 | 0.037* | 16 | 14 | 24 | 0.411 |
Had fresh water contact (missing data = 160) | 109 (36) | 27 | 47 | 28 | 0.001* | 38 | 35 | 0.584 | 26 | 50 | 33 | 14 | <0.001* | 6 | 31 | 59 | <0.001* | 37 | 24 | 46 | 0.243 |
Walking barefoot often/sometimes (missing data = 7) | 322 (71) | 64 | 80 | 69 | 0.002* | 74 | 69 | 0.326 | 88 | 79 | 68 | 55 | <0.001* | 65 | 70 | 77 | 0.359 | 74 | 59 | 55 | 0.015* |
Unprotected sex with local (missing data = 27) | 8 (2) | 4 | 1 | 0 | 0.067d | 2 | 2 | 1.000d | 0 | 1 | 4 | 1 | 0.239d | 0 | 2 | 3 | 0.632d | 2 | 0 | 3 | 0.587d |
Other close contact with local (kissing / sharing meals) (missing data = 26) | 82 (19) | 23 | 17 | 9 | 0.055 | 17 | 20 | 0.336 | 18 | 25 | 19 | 8 | 0.007* | 8 | 15 | 36 | <0.001* | 17 | 24 | 33 | 0.039* |
Had insect stings (missing data = 22) | 335 (76) | 75 | 81 | 67 | 0.058 | 75 | 77 | 0.657 | 59 | 88 | 75 | 62 | <0.001* | 19 | 77 | 93 | <0.001* | 76 | 65 | 91 | 0.032* |
Traveler profiles
Traveler profiles by age
Traveler profiles by destinations
Illness
Contracted illness a % | Odds ratio (95 % confidence interval) | p-value | ||
---|---|---|---|---|
Total (missing data = 1) | 79 | |||
Sex (missing data = 0) | ||||
Male | 75 | 1.0 | ||
Female | 81 | 1.5 | (1.0–2.4) | 0.079* |
Age group (missing data = 0) | <0.001* | |||
0–17 | 66 | 1.0 | ||
18–35 | 89 | 4.3 | (1.9–9.9) | 0.001 |
36–55 | 73 | 1.4 | (0.6–3.2) | 0.380 |
56– | 71 | 1.3 | (0.6–2.8) | 0.582 |
Geographic region (missing data = 0) | <0.001* | |||
Europe, Northern America | 20 | 1.0 | ||
Latin America and the Caribbean | 66 | 7.7 | (1.9–32.0) | 0.005 |
Northern Africa, Western Asia | 67 | 8.0 | (1.4–45.8) | 0.019 |
Southern Africa | 62 | 6.4 | (1.4–28.4) | 0.015 |
Western Africa, Middle Africa | 79 | 14.9 | (3.8–58.5) | <0.001 |
Eastern Africa | 84 | 21.6 | (5.4–85.8) | <0.001 |
Eastern Asia, Central Asia | 56 | 5.0 | (0.8–31.0) | 0.084 |
South-Eastern Asia | 87 | 26.6 | (6.7–106.1) | <0.001 |
Southern Asia | 91 | 41.3 | (9.1–188.5) | <0.001 |
Duration of travel, days (missing data = 0) | <0.001* | |||
1–7 | 52 | 1.0 | ||
8–29 | 77 | 3.0 | (1.4–6.7) | 0.006 |
30–160 | 94 | 14.4 | (4.7–44.1) | <0.001 |
Purpose of travel (missing data = 1) | 0.813 | |||
Vacation | 78 | 1.0 | ||
Business | 82 | 1.2 | (0.5–2.9) | 0.636 |
Other/multiple b | 82 | 1.2 | (0.5–2.9) | 0.636 |
Accommodation (missing data = 11) c | <0.001* | |||
Hotel | 68 | 1.0 | ||
Home of a local | 87 | 3.2 | (1.5–6.8) | 0.003 |
Guest house | 87 | 3.1 | (1.8–5.2) | <0.001 |
Location (missing data = 22) c | ||||
City | 71 | 1.0 | ||
Countryside/jungle | 83 | 2.0 | (1.3–3.3) | 0.003* |
Used other than bottled water (missing data = 3) c | 76 | 0.8 | (0.3–2.2) | 0.710 |
Ate uncooked meat/fish (missing data = 4) | 66 | 0.4 | (0.2–0.8) | 0.006* |
Ate salads (missing data = 26) | 78 | 0.7 | (0.4–1.2) | 0.192 |
Diet (missing data = 159) | ||||
Omnivore | 82 | 1.0 | ||
Vegetarian | 89 | 1.8 | (0.5–6.2) | 0.353 |
Used milk as part of diet (missing data = 161) | 83 | 1.0 | (0.1–8.5) | 1.000e |
Site of meals (missing data = 12) c | ||||
Restaurant more than 50 % of meals | 79 | 1.0 | ||
Own household and sometimes elsewhere | 79 | 1.0 | (0.5–1.8) | 0.996 |
Alcohol consumption (missing data = 67) d | ||||
0–2 units per day | 81 | 1.0 | ||
3– units per day | 74 | 0.7 | (0.4–1.1) | 0.102 |
Did not always use utensils (missing data = 23) | 85 | 1.7 | (1.0–3.0) | 0.058* |
Did not wash hands always/often (missing data = 13) | 72 | 0.6 | (0.3–1.2) | 0.138 |
No WC as a toilet (missing data = 7) | 85 | 1.6 | (0.8–3.2) | 0.159 |
Had fresh water contact (missing data = 160) | 84 | 1.7 | (0.9–3.1) | 0.109 |
Walking barefoot often/sometimes (missing data = 7) | 79 | 1.0 | (0.6–1.7) | 0.990 |
Unprotected sex with local (missing data = 27) | 100 | 1.0 | (1.0–1.0) | 0.213e |
Other close contact with local (missing data = 26) | 88 | 2.2 | (1.1–4.4) | 0.030* |
Had insect stings (missing data = 22) | 84 | 3.1 | (1.9–5.1) | <0.001* |
Proportion of those contracting | AOR (95 % CI) for contracting illness among | ||
---|---|---|---|
illness among travelers with | travelers with the given risk factor in multivariable | ||
the given risk factor (%) | analysis with multiple imputations c | p-value | |
Gender | |||
male | 75 | 1.00 | |
female | 81 | 1.73 (1.03–2.91) | 0.040* |
Age, years b |
N/A
| 1.06 (0.994–1.14) | 0.076 |
Age, quadratic term b |
N/A
| 0.999 (0.998–1.00) | 0.018* |
Geographic region |
N/A
| ||
Europe, Northern America | 20 | 1.00 | |
Latin America and the Caribbean | 66 | 7.90 (1.66–37.6) | 0.009* |
Northern Africa, Western Asia | 67 | 11.9 (1.82–78.0) | 0.010* |
Southern Africa | 62 | 9.72 (1.85–51.2) | 0.007* |
Western Africa, Middle Africa | 79 | 15.5 (3.50–68.7) | <0.001* |
Eastern Africa | 84 | 18.5 (4.08–83.8) | <0.001* |
Eastern Asia, Central Asia | 56 | 6.41 (0.930–44.2) | 0.059 |
South-Eastern Asia | 87 | 21.2 (4.48–100) | <0.001* |
Southern Asia | 91 | 32.4 (6.24–168) | <0.001* |
Duration of travel, days b |
N/A
| 1.025 (1.00–1.05) | 0.048* |
Accommodation |
N/A
| ||
hotel | 68 | 1.00 | |
home of a local | 87 | 2.36 (0.922–6.06) | 0.073 |
guest house | 87 | 1.78 (0.940–3.36) | 0.077 |
Eating uncooked meat/fish | |||
did not eat uncooked meat/fish | 81 | 1.00 | |
ate uncooked meat/fish | 66 | 0.303 (0.147–0.625) | 0.001* |
During journey, N | Ongoing or started on arrival, N | Newly onset during follow-up, N | |
---|---|---|---|
N/459 (%a) | N/453 (%a) | N/233 (%a) | |
Any symptom | 351 (76) | 113 (25) | 74 (32) |
travelers' diarrhea | 312 (68) | 78 (17) | 5 (2) |
skin problem b | 78 (17) | 2 (0) | 9 (4) |
fever >37,5 °C | 74 (16) | 6 (1) | 20 (9) |
vomiting | 55 (12) | 2 (0) | 1 (0) |
respiratory tract infection | 26 (6) | 17 (4) | 9 (4) |
urinary tract infection | 17 (4) | 1 (0) | 4 (2) |
ear infection | 5 (1) | 4 (1) | 1 (0) |
other gastrointestinal symptoms | 19 (4) | 2 (0) | 4 (2) |
other symptoms | 16 (3) | 6 (1) | 40 (17) |
Contacts to health care | 47 (10) | 1 (0) | 50 (21) |
Outpatient contact with health care c | 44 (10) | 1 (0) | 46 (20) |
travelers’ diarrhea | 20 (4) | 0 (0) | 16 (7) |
skin problem d | 9 (2) | 0 (0) | 5 (2) |
respiratory tract infection | 8 (2) | 0 (0) | 5 (2) |
ear infection | 4 (1) | 0 (0) | 1 (0) |
malaria / suspected malaria | 3 (1) | 0 (0) | 0 (0) |
musculosceletal problem | 2 (0) | 0 (0) | 6 (3) |
urinary tract infection | 2 (0) | 0 (0) | 2 (1) |
other reason | 3 (1) | 1 (0) | 11 (5) |
Inpatient (hospitalization) | 3 (1) | 0 (0) | 4 (2) |
travelers’ diarrhea | 2 (0) | 0 (0) | 1 (0) |
fever >37,5 °C | 0 (0) | 0 (0) | 1 (0) |
respiratory tract infection | 0 (0) | 0 (0) | 1 (0) |
suspected malaria | 0 (0) | 0 (0) | 1 (0) |
other reason | 1 (0) | 0 (0) | 0 (0) |