Volume 20, Number 9—September 2014
Dispatch
Asymptomatic, Mild, and Severe Influenza A(H7N9) Virus Infection in Humans, Guangzhou, China
Table 2
Demographic, epidemiologic, and clinical characteristics of patients with severe and mild influenza A(H7N9) cases, Guangzhou, China, April 1, 2013–March 7, 2014*
| Characteristic | Severe cases, n = 16 | Mild cases, n = 4† |
|---|---|---|
| Sex ratio, M:F | 11:5 | 1:3 |
| Age, y, median (range) |
66 (29–83) |
5 (4–17) |
| Age group, y | ||
| 0–14 | 0 | 3 (75) |
| 15–59 | 5 (31) | 1 (25) |
| >60 |
11 (69) |
0 |
| Type of residence | ||
| Urban | 12 (75) | 4 (100) |
| Rural |
4 (25) |
0 |
| Occupation | ||
| Retired | 11 (69) | 0 |
| Housewife | 2 (13) | 0 |
| Farmer | 2 (13) | 0 |
| Tofu vendor in retail wet market | 1 (6) | 0 |
| Kindergarten student | 0 | 3 (75) |
| Primary or high school student |
0 |
1 (25) |
| History of poultry exposure‡ | ||
| Direct contact | 6§ (38) | 0 |
| Indirect contact | 9¶ (56) | 1# (25) |
| Unknown |
3 (19) |
3 (75) |
| Underlying medical conditions** |
12 (75) |
0 |
| Preliminary diagnosis at the first hospital visit | ||
| Influenza | 0 | 3 (75) |
| Upper respiratory tract infection | 6 (38) | 1 (25) |
| Pneumonia |
10†† (63) |
0 |
| Required hospitalization | 16 (100) | 1 (25) |
| Illness progressed to pneumonia | 16 (100) | 0 |
| Received oseltamivir treatment | 15 (94) | 4 (100) |
| Admitted to intensive care unit | 14 (88) | 0 |
| No. hospitals visited, median (IQR) |
3 (1–4) |
1 (1–2) |
| Time from illness onset to first medical care, median (IQR) | 5 d (1–12 d) | 6h (3–24h) |
| For patients in >60 y age group |
7 d (2–12 d) |
|
| Time from illness onset to antiviral therapy, median (IQR) | 7 d (3–12 d) | 1 d (6 h–4 d) |
| Time from illness onset to laboratory confirmation, median (IQR) | 8 d (7–13 d) | 3 d (2–5 d) |
| Length of illness, median (IQR) |
24 d (11–32 d) |
7 d (6–8 d) |
| Outcome | ||
| Recovered and discharged | 4 (25) | 4 (100) |
| Still in hospital‡‡ | 1 (6) | 0 |
| Died | 11 (69) | 0 |
*Values are no. (%) patients except as indicated. LPM, live poultry market; IQR, interquartile range.
†Includes the confirmed mild case detected from follow-up of close contacts.
‡Direct contact: bought poultry, slaughtered poultry, handled poultry meat, raised backyard poultry. Indirect contact: visited LPMs.
§Four case-patients raised backyard chickens, 3 slaughtered live chickens, and 1 handled chicken meat.
¶Five case-patients visited LPMs daily; 4 visited LPMs several times.
#Case-patient’s father managed a live poultry stall in a contaminated LPM; case-patient visited the stall several times.
**Diabetes, hypertension, uremia, chronic obstructive pulmonary disease, and coronary heart disease.
††Nine case-patients were >60 y of age.
‡‡As of April 7, 2013.
1These first authors contributed equally to this article.
2These senior authors contributed equally to this article.