Clustering cases of Chlamydia psittaci pneumonia mimicking COVID-19 pneumonia

Table 1 The clinical characteristics and laboratory tests of patients with coronavirus disease 2019 and psittacosis

	Patient 0	Patient 1	Patient 2	Patient 3	Patient 4	Patient1	Patient2	Psittacosis (n = 6)	COVID-19 (n = 31)	P value
Age	62	36	29	32	26	47	48	34.00 (28.25-47.25)	50.00 (32.00-66.00)	0.073
Sex	Male	Male	Female	Female	Male	Male	Male	NA	NA	0.660
Male								4	16
Female								2	15
Hemoglobin (g/dL); (male normal range 130-175; female normal range 115-150)	124	142	135	134	163	157	143	142.50 (134.75-158.50)a	135.00 (120.00-141.00)	0.054
White blood cell count (× 109/L); (normal range 3.5-9.5)	7.14	10.43	10.07	11.7	10.53	10.26	14.36	10.48 (10.21-12.37)	4.62 (3.31-6.17)	0.000
Neutrophil count (× 109/L); (normal range 1.8-6.3)	5.92	7.57	6.61	8.66	8.41	6.3	11.76	7.99 (6.53-9.44)	2.89 (1.95-3.89)	0.000
Lymphocyte count (× 109/L); (normal range 1.1-3.2)	0.66	2.04	2.33	2.21	1.11	1.28	1.43	1.74 (1.24-2.24)	1.09 (0.71-1.67)	0.044
Platelet count (× 109/L); (normal range 125-350)	186	369	249	241	193	214	204	227 (201-279)	183 (124-227)	0.035
Eosinophilic count (× 109/L); (normal range 0.02-o.52)	0	0.1	0.01	0	0	0	0	0.000 (0.000-0.325)	0.100 (0.000-0.400)	0.265
C-reactive protein (mg/L); (normal range 0.0-5.0)	127.17	12.17	31.87	50.55	58.01	112.13	141.35	54.28 (26.95-119.44)	15.60 (4.77-47.73)	0.035
Sodium (mmol/liter)	NA	140.9	1136.2	134.2	136.1	129.7	137.4	136.15 (133.08-138.28)	135.90 (133.40-137.40)	0.857
Potassium (mmol/liter)	NA	4.09	3.42	3.42	3.94	4.11	3.52	3.73 (3.42-4.10)	4.02 (3.58-4.37)	0.302
Calcium (mmol/liter)	NA	2.11	2.28	2.03	2	2.2	2.16	2.14 (2.02-2.22)	1.20 (1.18-1.22)	0.000
The number of detected sequences of C. psittaci	NA	274	3	82	254	NA	NA	NA	NA	NA

^aThe data presented are the medians (IQR). COVID-19: Coronavirus disease 2019; NA: Not applicable.

Table 2 The imaging findings of patients with coronavirus disease 2019 and psittacosis

	Psittacosis (n = 6)	COVID-19 (n = 13)	P value
Predominant lesion type			0.221
GGO	0 (0)	5 (38.5)
Consolidation	3 (50)	5 (38.5)
Mixed GGO and consolidation	3 (50)	3 (23.1)
Air bronchogram	6 (100)	8 (61.5)	0.128
Vascular enlargement	1 (16.7)	12 (92.3)	0.003
Margin (uneasily differentiated)	6 (100)	8 (61.5)	0.128
Reticulation	5 (75)	9 (69.2)	1.000
Pleural effusions	6 (100)	1 (7.7)	0.002
Craniocaudal distribution			0.026
Upper lung predominant	0 (0)	2 (15.4)
Lower lung predominant	6 (100)	4 (30.8)
No craniocaudal distribution	0 (0)	7 (53.8)
Transverse distribution			0.255
Central	0 (0)	0 (0)
Peripheral	6 (100)	9 (69.2)
No transverse distribution	0 (0)	4 (30.8)
Lung region distribution			0.001
Unilateral	6 (100)	2 (15.4)
Bilateral	0 (0)	11 (84.6)
Number of involved lung lobes			0.006
1	6 (100)	2 (15.4)
2	0 (0)	3 (23.1)
3	0 (0)	0 (0)
4	0 (0)	5 (38.5)
5	0 (0)	5 (38.5)

Note: The data are presented as the numbers (percentages). GGO: Ground-glass opacity.