Construction sites as an important driver of dengue transmission: implications for disease control

BMC Infectious Diseases

Table 2 Summary of construction site-associated clusters in which the first known case was notified from the construction site or from the surrounding areas

	2013				2014				2015				2016
Total no. of clusters	50				88				41				50
No. of clusters that notified the first case from a construction site^a	Yes		No		Yes		No		Yes		No		Yes		No
	35		12		54		28		25		12		31		9
Cluster size^b	≥10	< 10	≥10	< 10	≥10	< 10	≥10	< 10	≥10	< 10	≥10	< 10	≥10	< 10	≥10	< 10
No. of clusters	24	11	9	3	19	35	11	17	6	19	3	9	6	25	3	6
No. of cases	1038	44	298	10	1546	112	836	54	425	59	112	30	231	79	107	25
Average cases per cluster	43.3	4	33.1	3.3	81.4	3.2	76.4	3.2	70.8	3.1	37.3	3.3	38.5	3.2	35.7	4.2
Odds ratio^c (95% CI)	0.73 (0.16–3.22)				0.84 (0.33–2.15)				0.95 (0.20–4.68)				2.08 (0.4–10.8)

^aNumbers given here are less than the total number of clusters stated because of the non-availability of index case information from certain clusters
^b≥10 = major clusters; < 10 = minor clusters
^cOdds ratio of construction site-associated clusters expanding into major clusters. CI = confidence interval

ISSN: 1471-2334