Seasonal patterns and spatial variation of Borrelia burgdorferi (sensu lato) infections in Ixodes ricinus in the Netherlands

Table 5 Results trend over time (years) for each location

Location	NIP^a			DON^b			DIN^b
	Estimate	Odds ratio	p	Estimate	Ratio	p	Estimate	Ratio	p
	β	e ^β	p	Estimate	Ratio	p	Estimate	Ratio	p
Bilthoven	− 0.1949	0.823	0.0037	0.1669	1.1816	0.0071	− 0.0473	0.9538	0.4939
Dronten	− 0.0700	0.932	0.3200	-0.1908	0.8263	0.0180	− 0.2273	0.7967	0.0100
Ede	− 0.1787	0.836	0.0014	0.0152	1.0153	0.7629	− 0.224	0.7993	7.68e-06
Gieten	− 0.0453	0.956	0.3890	0.1024	1.1078	0.0729	0.0493	1.0505	0.433
Hoog Baarlo	− 0.2172	0.805	0.0035	0.1622	1.1761	0.0037	− 0.1464	0.8638	0.0185
Kwade Hoek	0.1292	1.030	0.1316	− 0.0101	0.9900	0.9357	0.1211	1.1287	0.5589
Montferland	− 0.1024	0.903	0.0458	0.0365	1.0372	0.3709	− 0.0799	0.9232	0.218
Schiermonnikoog	0.0109	1.011	0.8920	0.0004	1.0004	0.9928	− 0.0631	0.9388	0.4740
Twiske	− 0.1877	0.829	0.0003	0.0966	1.1014	0.0359	− 0.0926	0.9116	0.2075
Vaals	NA^c	NA^c	NA^c	− 0.0866	0.9170	0.2849	0.0327	1.0332	0.7296
Veldhoven	− 0.0074	0.993	0.9256	0.2385	1.2693	5.72e-08	0.1069	1.1128	0.2268
Wassenaar	− 0.0547	0.947	0.0419	0.0959	1.1006	0.0241	0.0747	1.0776	0.0926
All locations	− 0.0843	0.919	4.04e-05	0.0705	1.0730	0.0011	− 0.0414	0.9594	0.1130

Estimated effect of the numerical value “Year” in model, which indicates the trend over time (over years)
Model outcomes in italics indicate that the model had convergence problems, and we used the squared absolute difference between the month and June (M = (|6-Month|)² instead of Month
^aFor the NIP, the estimate β is obtained using the beta-binomial model, with a logit link. The corresponding estimated odds ratio (calculated as e^β), indicates the ratio between the odds of a tick being infected in 1 year and the next, with an odds ratio > 1 indicating an increase in the prevalence over time and an odds ratio < 1 indicating a decrease
^b For the DON and DIN (estimated from negative binomial models with log link), the estimated β can be used to calculate the ratio (e^β) of the estimated numbers of ticks between two consecutive years, with an odds ratio > 1 indicating an increase in numbers and an odds ratio < 1 indicating a decrease in the numbers
^cNA indicates that the model-fitting algorithm did not converge

ISSN: 1756-3305