Table 1.

Main characteristics and risk factors of the 4 dually infected CT-positive and NG-positive cases

	Case 1	Case 2	Case 3	Case 4
Sex	female	female	female	female
Age	17 yr	17 yr	17 yr	18 yr
Ethnicity	Dutch	Surinamese	Dutch	Surinamese
Level of urbanisation *	high urban	very high urban	very high urban	high urban
Level of education	unknown	intermediate	low	high
Symptoms:
Intermenstrual and/or postcoital bleeding	+	-	+	-
Painfull/frequent mixturation	+	+	+	+
Lower abdominal pain	-	+	+	+
Lifetime partners	2–5	6–10	6–10	6–10
Partners previous 6 months	1	1	2–5	2–5
New partner previous 2 months	-	-	+	+
Condom use last sexual contact	-	-	-	-
History of previous STI	+	-	+	-

* According to Area Address Density: very high urban (> 2500 addresses/km²); high urban (1500–2500 addresses/km²); moderate urban (1000–1500 addresses/km²);) low urban (500–1000 addresses/km²); and rural (<500 addresses/km²) http://www.cbs.nl.