Table 2.

Prevalence and factors associated with chikungunya virus exposure in humans, Nigeria, 2011–2018.

Variable	n/N	Seroprevalence % (95% CI)	Unadjusted Odds Ratio (95% CI)	p-Value	Adjusted Odds Ratio (95% CI)	p-Value
Age (continuous)	290/701	41.3 (37.6, 45.1)	1.01 (1.00, 1.02)	<0.001	1.01 (1.01, 1.02)	<0.001
0–17	29/126	23.0 (15.9, 31.3)	REF
18–90	261/575	45.3 (41.2, 49.5)	2.78 (1.77, 4.34)	<0.001	2.15 (1.33, 3.45)	0.002
Gender
Female	132/329	40.1 (34.7, 45.6)	0.90 (0.67, 1.22)	0.528
Male	158/372	42.4 (37.3, 47.6)	REF
Location, Year
Ibadan, 2018	103/300	34.3 (28.9, 40.0)	0.44 (0.31, 0.63)	<0.001	0.67 (0.16, 2.72)	0.577
Jos, 2017	66/177	37.2 (30.1, 44.8)	0.50 (0.33, 0.75)
Abuja, 2011	121/224	54.0 (47.2, 60.6)	REF
Occupation
Butcher/Meat seller	70/141	49.6 (41.1, 58.1)	1.81 (1.21, 2.72)	<0.001	0.63 (0.16, 2.39)	0.500
Livestock Trader/Vet	13/27	48.1 (28.6, 68.0)	1.71 (0.77, 3.77)		0.57 (0.12, 2.57)	0.472
Abattoir worker	32/46	69.5 (54.2, 82.2)	4.21 (2.15, 8.23)		1.66 (0.39, 7.01)	0.491
Unknown	66/177	37.2 (30.1, 44.8)	1.09 (0.74, 1.60)		0.37 (0.09, 1.47)	0.162
Others	189/310	60.9 (55.2, 66.4)	REF
Animal exposure
Unknown	66/177	37.2 (30.1, 44.8)	0.96 (0.60, 1.52)	0.205	-	-
Yes	172/388	44.3 (39.3, 49.4)	1.28 (0.86, 1.91)		1.17 (0.69, 1.97)	0.550
No	52/136	38.2 (30.0, 46.9)	REF
Health status
Sick individual	169/477	35.4 (31.1, 39.9)	0.46 (0.33, 0.65)	< 0.001
Non-sick individual	121/224	54.0 (47.2, 60.6)	REF
Presence of fever
Yes	237/595	39.8 (35.8, 43.8)	0.66 (0.43, 1.00)	0.051	1.03 (0.59, 1.80)	0.899
No	53/106	50.0 (40.1, 59.8)	REF
Malaria parasite
Unknown	187/401	46.6 (41.6, 51.6)	0.96 (0.56, 1.63)	<0.001
Yes	73/237	30.8 (24.9, 37.1)	0.48 (0.27, 0.86)		0.43 (0.22, 0.82)	0.011
No	30/63	47.6 (34.8, 60.5)	REF

n = number positive for anti-chikungunya virus IgG; N = total samples examined; CI = confidence interval.