Table 1.

Characteristics of subjects tested for CHIKV during the outbreak in 2020

Parameter	Total tested	Positive		Negative		Sig	OR (95% CI)
		N	%	N	%
Number of subjects	1194	331	27.7	863	72.3
Month
January	147	19	12.9	128	87.1	< 0.001
February	140	40	28.6	100	71.4
March	134	36	26.9	98	73.1
April	94	25	26.6	69	73.4
May	97	39	40.2	58	59.8
June	51	4	7.8	47	92.2
July	125	32	25.6	93	74.4
August	102	35	34.3	67	65.7
September	77	21	27.3	56	72.7
October	91	29	31.9	62	68.1
November	71	28	39.4	43	60.6
December	65	23	35.4	42	64.6
Season
Rainy season (May–Oct)	543	160	29.5	383	70.5	0.220	1.2 (0.9–1.5)
Dry season (Nov–Apr)	651	171	26.3	480	73.7
Site
Battambang	88	7	8.0	81	92.0	< 0.001
Kampong Speu	303	60	19.8	243	80.2
Kandal	507	166	32.7	341	67.3
Kratie	193	82	42.5	111	57.5
Preah Vihear	61	8	13.1	53	86.9
Sihanoukville	42	8	19.0	34	81.0
Area
Urban	810	226	27.9	584	72.1	0.844	1.0 (0.8–1.4)
Rural	384	105	27.3	279	72.7
Age
Mean (SD)	25.7 (± 17.8)	28.3 (± 17.3)		24.7 (± 17.9)		0.002
Median	22.5	25.0		21.0
IQR	11–38	14–40		10–36
Age group
Adult (age ≥ 18 years)	712	234	32.9	478	67.1	< 0.001	1.9 (1.5–2.6)
Children	482	97	20.1	385	79.9
02–05 years	118	20	16.9	98	83.1	< 0.001
06–17 years	364	77	21.2	287	78.8
18–45 years	510	176	34.5	334	65.5
46–65 years	174	48	27.6	126	72.4
> 65 years	28	10	35.7	18	64.3
Gender
Male	589	168	28.5	421	71.5	0.543	1.1 (0.8–1.4)
Female	605	163	26.9	442	73.1
Education
No education	648	183	28.2	465	71.8	0.413
Primary	238	58	24.4	180	75.6
Secondary and higher	308	90	29.2	218	70.8
Occupation
Employed	182	51	28.0	131	72.0	0.915	1.0 (0.7–1.4)
Unemployed	1012	280	27.7	732	72.3
Symptom
Fever (100%)	1194	331	27.7	863	72.3	–	–
Headache	1153	323	28.0	830	72.0	0.235	1.6 (0.8–3.7)
Sore throat	927	244	26.3	683	73.7	0.05	0.7 (0.5–1.0)
Chills	885	259	29.3	626	70.7	0.042	1.4 (1.1–1.8)
Cough	877	219	25.0	658	75.0	< 0.001	0.6 (0.5–0.8)
Malaise	815	223	27.4	592	72.6	0.682	0.9 (0.7–1.2)
Muscle aches	493	151	30.6	342	69.4	0.061	1.3 (1.0–1.7)
Joint pain	332	109	32.8	223	67.2	0.015	1.4 (1.1–1.9)
Nausea	255	106	41.6	149	58.4	< 0.001	2.3 (1.7–3.0)
Vomit	132	57	43.2	75	56.8	< 0.001	2.2 (1.5–3.2)
Abdominal cramp	67	18	26.9	49	73.1	0.887	1.0 (0.5–1.7)
Shortness of breath	65	17	26.2	48	73.8	0.787	0.9 (0.5–1.6)
Lesion	62	36	58.1	26	41.9	< 0.001	3.9 (2.3–6.7)
Rash	32	10	31.3	22	68.8	0.643	1.2 (0.6–2.5)
Diarrhea	31	9	29.0	22	71.0	0.851	1.1 (0.5–2.3)
Seizure	10	1	10.0	9	90.0	0.225	0.3 (0.1–1.8)
Bloody urine	1	1	100.0	0	0.0	–	–
Bleeding	1	0	0.0	1	100.0	–	–
Jaundice	1	1	100.0	0	0.0	–	–