A comparative study of clinical manifestations, haematological and serological responses after experimental infection with Anaplasma phagocytophilum in two Norwegian sheep breeds

Table 1 Mean and standard deviation (± SD) of different clinical variables in 5-month-old lambs of two Norwegian Sheep breeds, Norwegian White (NW) and Old Norse (ON), respectively, infected with one variant of A. phagocytophilum

	2008			2009
	NW	ON	P-value	NW	ON ^#	P-value
Incubation period (days)	3.0 ± 0.0	2.9 ± 0.3	ns	3.0 ± 0.0	9.6 ± 2.4	p < 0.0001
Max. temp. (°C)	41.87 ± 0.18	41.64 ± 0.11	ns	41.86 ± 0.13	40.96 ± 0.54	p < 0.001
Duration of fever (days)	8.9 ± 2.77	5.6 ± 1.02	p < 0.01	8.0 ± 3.07	5.4 ± 3.11	Ns
Magnitude of fever (mm ² )	912 ± 158	503 ± 89	p < 0.001	737 ± 231	275 ± 174	p < 0.001
Nadir of neutropenia (<0.7 × 10 ⁹ litre ^-1 )	0.22 ± 0.06	0.22 ± 0.08	ns	0.26 ± 0.10	0.28 ± 0.15	Ns
Duration of neutropenia (days)	9.1 ± 2.38	10.1 ± 2.21	ns	6.7 ± 2.24	5.7 ± 2.49	Ns
Max. infection rate (%)	49.0 ± 3.46	44.6 ± 5.66	ns	52.9 ± 1.79	46.6 ± 9.76	Ns
Weight loss (%) ^a	- 10.7 ± 3.21	-9.5 ± 4.63	ns	-9.6 ± 2.81	1.4 ± 4.20	p < 0.001

^a weight loss was measured one week after inoculation; ns - not significant
^# only seven lambs were infected
The study was performed in two subsequent years, 2008 and 2009, respectively. Ten lambs in each group were inoculated. A two-sample t test was used for statistical analysis

ISSN: 1751-0147