Isolation of herpesvirus and Newcastle disease virus from White Storks (Ciconia ciconia) maintained at four rehabilitation centres in northern Germany during 1983 to 2001 and failure to detect antibodies against avian influenza A viruses of subtypes H5 and H7 in these birds

Figures & data

Table 1.  Number of White Storks examined at each centre and number of samples obtained from peripheral white blood cells, swabs from the pharynx and cloaca, and cloacal content.

		Types and total number of samples obtained from storks
Rehabilitation centre	Number of storks examined	Peripheral white blood cells: virus isolation^a	Peripheral blood plasma: antibody tests^b	Swabs from pharynx and cloaca: virus isolation^a	Cloacal content: bacteriology and parasitology^c
V	116	552	154	23	552
L	58	156	20	1	156
S	16	122	17	10	156
B	63	118	0	0	118
Total	253	948	191	34	948
^aVirus isolation in CEF cultures. Most but not all storks were repeatedly tested.
^bA total of 191 blood plasma samples from spring 1984 to 2000 were used in virus neutralization tests in CEF cultures for detection of neutralizing antibodies against stork herpesvirus, in haemagglutination inhibition tests for antibodies against APMV-1 and for avian influenza A virus of subtypes H5 and H7.
^cCultures for aerobic bacteria and microscopic examination for intestinal parasites.

Table 2.  Number of White Storks at four rehabilitation centres and rate of herpesvirus isolations from blood plasma.

	Number of herpesvirus isolations from White Storks
Rehabilitation centre	Number of tested storks	Herpesvirus isolated	No herpesvirus isolated	% rate isolation of number of tested storks
V	116	52	64	44.8
L	58	17	41	29.3
S	16	4	12	25.0
B	63	10	53	15.9
Total	253	83	170	32.8

Table 3.  Frequency of stork herpesvirus isolations from peripheral blood leukocytes as affected by the season of sampling.

		Number of samples tested
Rehabilitation centre	Season of sampling	Positive	Negative	Total	% positive of total tested	χ^2	P value
V	Spring	73	197	270	30.5
	Autumn	23	259	282	8.9	34.227	<0.001
L	Spring	17	57	74	23.0
	Autumn	4	78	82	4.9	10.933	<0.001
S	Spring	4	55	59	6.8	Not applicable^a
	Autumn	5	58	63	7.9		0.060
B	Spring	5	17	22	22.7
	Autumn	7	89	96	7.3	4.668	0.031
Sub-total	Spring	99	326	425	23.3
	Autumn	39	484	523	7.5	47.282	<0.001
Total	Spring+	138	810	948	14.6	–	–
	Autumn
^aChi-squared test not applicable due to small numbers.

Table 4.  Frequencies of stork herpesvirus isolations as affected by the number of bleedings for viraemia per stork.

		Number of blood samplings from each stork and herpesvirus isolations
		1 to 8 samplings				9 to 16 samplings				17 to 24 samplings				25 to 32 samplings
Rehabilitation centre	Number of storks	n	+ve	−ve	% +ve	n	+ve	−ve	% +ve	n	+ve	−ve	% +ve	n	+ve	−ve	% +ve
V	116	98	38	60	38.8	10	7	3	70.0	5	5	0	100.0	3	3	0	100.0
L	58	58	17	41	29.3	0				0				0
S	16	11	1	10	9.1	3	2	1	66.7	2	1	1	50.0	0
B	63	62	10	52	16.1	1	0	1	0	0				0
Total	253	229	55	163	28.8	14	9	5	64.3	7	6	1	85.7	3	3	0	100.0
+ve, positive; −ve, negative.

Table 5.  Herpesvirus neutralizing antibodies in relation to isolations of stork herpesvirus.

	Neutralizing antibodies (log2) titres against stork herpesvirus in blood plasma samples with or without herpesvirus isolations
Herpesvirus isolation	≤2^a	3	4	5	6	7	8	9	10	11	Number of antibody-positive/number of tested samples
Yes	9	0	0	7	3	1	2	1	1	0	15/24
No	4	3	30	40	35	27	14	10	2	2	163/167
^aTitres of log2<2 are interpreted as non-specific.

Table 6.  APMV-1 haemagglutination inhibition titres of plasma samples.

		Number of blood plasma samples with HI titre^a in log2
Rehabilitation centre	Number tested	≤3	4	5	6	7	≥8
V	154	139	0	1	2	5	7
L	20	19	1
S	17	17
Total	191	175	1	1	2	5	7
^aTitres of log2<3 are interpreted as non-specific (OIE, 2000).