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Table 2 Characteristics of the trips made outside of Swaziland (positive and negative cases), with a percentage (%) of the total group size (n) and 95% confidence intervals (95% CI)

From: Travel patterns and demographic characteristics of malaria cases in Swaziland, 2010–2014

Variable Characteristics Risk factors
Positive cases Negative cases p2) OR (95% CI) Pr(>|z|)
n % (95% CI) n % (95% CI)    
Total 947   306     
Reason of travel      0.003   
Lives/staying there 51 5.39 (3.94–6.82) 37 12.09 (8.44–15.74)   1  
Business 51 5.39 (3.97–6.82) 30 9.8 (6.47–13.14)   1.23 (0.67–2.3) 0.5063
Holiday 19 2.01 (1.11–2.9) 11 3.59 (1.51–5.68)   1.25 (0.54–3.02) 0.6049
Other 6 0.63 (0.13–1.14) 15 4.9 (2.48–7.32)   0.29 (0.1–0.79) 0.0194
Visiting friends/relatives 448 47.31 (44.13–50.49) 213 69.61 (64.45–74.76)   1.53 (0.96–2.4) 0.068
Didn’t respond* 372 39.28 (36.7–42.39) 0     
Travel protection      0.902   
Any protection 173 18.27 (15.81–20.73) 55 17.97 (13.67–22.28)   1  
No protection 773 81.63 (79.16–84.09) 251 82.03 (77.72–86.33)   0.98 (0.7–1.36) 0.902
Didn’t respond* 1 0.11 (−0.1–0.31) 0     
Travel protection      0.045   
Bed net 83 8.76 (6.96–10.57) 38 12.42 (8.72–16.11)   1  
None 773 81.63 (79.16–84.09) 251 82.03 (77.72–86.33)   1.41 (0.93–2.11) 0.10005
Repellent coil 28 2.96 (1.88–4.04) 9 2.94 (1.05–4.83)   1.42 (0.63–3.46) 0.41109
Chemoprophylaxis (chemop) 53 5.6 (4.14–7.06) 8 2.61 (0.83–4.4)   3.03 (1.37–7.45) 0.00934
Bed net + repellent coil 4 0.42 (0.01–0.84) 0     
Bed net + chemop 4 0.42 (0.01–0.84) 0     
Chemop + repellent coil 1 0.11 (−0.1–0.31) 0     
Didn’t respond* 1 0.11 (−0.1–0.31) 0     
Bed net at home      <0.0001   
Bed net 134 14.15 (11.93–16.37) 112 36.6 (31.2–42)   1  
None 813 85.85 (83.63–88.07) 194 63.4 (58–68.9)   3.5 (2.61–4.71) <0.0001
Admin unit/Country      <0.0001   
KwaZulu-Natal (South Africa) 16 1.69 (0.87–2.51) 37 12.09 (8.44–15.74)   1  
Eastern Cape (South Africa) 0   1 0.33 (−0.31–0.97)    
Free State (South Africa) 0   1 0.33 (−0.31–0.97)    
Gauteng (South Africa) 4 0.42 (0.01–0.84) 22 7.19 (4.3–10.08)   0.42 (0.11–1.32) 0.162596
Limpopo (South Africa) 2 0.21 (−0.08–0.5) 7 2.29 (0.61–3.96)   0.66 (0.09–3.1) 0.628196
Mpumalanga (South Africa) 19 2.01 (1.11–2.9) 76 24.84 (20–29.68)   0.58 (0.27–1.26) 0.164403
North West (South Africa) 2 0.21 (−0.08–0.5) 3 0.98 (−0.12–2.08)   1.54 (0.19–10.18) 0.652284
Western Cape (South Africa) 0   1 0.33 (−0.31–0.97)    
Gaza (Mozambique) 123 12.99 (10.85–15.13) 5 1.63 (0.21–3.05)   56.89 (21.13–185.28) <0.0001
Inhambane (Mozambique) 281 29.67 (26.76–32.58) 17 5.56 (2.99–8.12)   38.22 (18.26–84.63) <0.0001
Manica (Mozambique) 0   1 0.33 (−0.31–0.97)    
Maputo (Mozambique) 71 7.5 (5.82–9.17) 45 14.71 (10.74–18.67)   3.65 (1.85–7.47) 0.000263
Maputo City (Mozambique) 315 33.26 (30.26–36.26) 86 28.1 (23.07–33.14)   8.47 (4.57–16.34) <0.0001
Nampula (Mozambique) 2 0.21 (−0.08–0.5) 0     
Nassa (Mozambique) 1 0.11 (−0.1–0.31) 0     
Sofala (Mozambique) 14 1.48 (0.71–2.25) 0     
Tete (Mozambique) 3 0.32 (−0.04–0.67) 0     
Zambezia (Mozambique) 4 0.42 (0.01–0.84) 0     
Cabo Delgado (Mozambique) 1 0.11 (−0.1–0.31) 0     
Equatorial Guinea 4 0.42 (0.01–0.84) 0     
Ethiopia 1 0.11 (−0.1–0.31) 0     
Ghana 1 0.11 (−0.1–0.31) 0     
Nigeria 1 0.11 (−0.1–0.31) 1 0.33 (−0.31–0.97)   2.31 (0.09–60.96) 0.561948
Malawi 2 0.21 (−0.08–0.5) 0     
Rwanda 1 0.11 (−0.1–0.31) 0     
Tanzania 1 0.11 (−0.1–0.31) 0     
Zambia 4 0.42 (0.01–0.84) 0     
Zimbabwe 3 0.32 (−0.04–0.67) 3 0.98 (−0.12–2.08)   2.31 (0.39–13.71) 0.335023
Uganda 3 0.32 (−0.04–0.67) 0     
Didn’t respond* 68 7.18 (5.54–8.82) 0     
Border crossing      <0.0001   
Mananga 7 0.74 (0.32–1.59) 31 10.13 (7.09–14.21)   1  
Mhlumeni/Goba 255 26.93 (24.15–29.9) 70 22.88 (18.37–28.07)   8.99 (4.75–17.77) <0.0001
Lomahasha/Namaacha 250 26.4 (23.64–29.35) 70 22.88 (18.37–28.07)   8.81 (4.66–17.43) <0.0001
Ngwenya/Oshoek 15 1.58 (0.92–2.66) 37 12.09 (8.76–16.4)   0.56 (0.19–1.5) 0.25901
Lavumisa/Golela 12 1.27 (0.69–2.27) 22 7.19 (4.66–10.84)   1.35 (0.53–3.4) 0.52929
Informal crossings 9 0.95 (0.46–1.86) 21 6.86 (4.4–10.45)   1.06 (0.39–2.81) 0.91193
Matsamo/Jeppe’s Reef 5 0.53 (0.19–1.3) 15 4.9 (2.87–8.13)   0.82 (0.23–2.56) 0.74437
Mbuzini 1 0.11 (0.01–0.68) 11 3.59 (1.9–6.53)   0.22 (0.01–1.31) 0.16956
Matsapha Airport 8 0.84 (0.39–1.73) 1 0.33 (0.02–2.09)   19.73 (3.23–382.87) 0.0069
Salitje/Onverwacht 0   5 1.63 (0.6–3.99)    
Mahamba 3 0.32 (0.08–1) 2 0.65 (0.11–2.6)   3.7 (0.56–30.31) 0.17419
Sandlane/Nerston 0   4 1.31 (0.42–3.54)    
Sicunusa/Houtkop 0   3 0.98 (0.25–3.08)    
Other (total)+ 8 0.84 (0.39–1.73) 14 4.58 (2.61–7.73)   1.41 (0.48–4.03) 0.52395
Other 3 0.32 (0.08–1) 3 0.98 (0.25–3.08)    
Sicancweni (other) 2 0.21 (0.04–0.85) 1 0.33 (0.02–2.09)    
Nsalitje (other) 0   2 0.65 (0.11–2.6)    
Phocweni (other) 2 0.21 (0.04–0.85) 0     
Tsambokhulu (other) 0   2 0.65 (0.11–2.6)    
Eticancweni (other) 0   1 0.33 (0.02–2.09)    
Insubane (other) 0   1 0.33 (0.02–2.09)    
Lubombo (other) 0   1 0.33 (0.02–2.09)    
Mahlahlane (other) 0   1 0.33 (0.02–2.09)    
Malabo international airport (other) 1 0.11 (0.01–0.68) 0     
Sicanco (other) 0   1 0.33 (0.02–2.09)    
Sitsasaweni (other) 0   1 0.33 (0.02–2.09)    
Didn’t respond* 374 39.49 (36.38–42.7) 0     
Means of transport      <0.0001   
Kombi (van) 256 27.03 (24.25–30) 175 57.19 (51.43–62.77)   1  
Large bus 139 14.68 (12.52–17.13) 60 19.61 (15.4–24.6)   1.58 (1.11–2.28) 0.0120
Airplane 9 0.95 (0.46–1.86) 2 0.65 (0.11–2.6)   3.08 (0.78–20.34) 0.1538
Bicycle 0   1 0.33 (0.02–2.09)    
Personal car 147 15.52 (13.31–18.02) 50 16.34 (12.47–21.07)   2.01 (1.39–2.94) 0.0003
Ride share 10 1.06 (0.54–2) 1 0.33 (0.02–2.09)   6.84 (1.29–126.02) 0.0680
Truck 1 0.11 (0.01–0.68) 0     
Walked 12 1.27 (0.69–2.27) 17 5.56 (3.37–8.91)   0.48 (0.22–1.03) 0.0614
Didn’t respond* 373 39.39 (36.27–42.59) 0     
  1. Risk factors are presented as odd ratios (OR) with 95% confidence intervals (95% CI) for the univariate model. p values from Wald test (Pr(>|z|)) for individual variables and p from X2 of the model tested against the null hypothesis. Those variables with (*) were not included in the model. Note: some individuals carried out more than one trip. Variables with the (+) indicate the total of other border crossing points not geolocated, and identified as ‘other’ in brackets