Infected or not: are PCR-positive oropharyngeal swabs indicative of low pathogenic influenza A virus infection in the respiratory tract of Mallard Anas platyrhynchos?

Table 1 Detection of influenza A virus by RRT-PCR, virus isolation, and immunohistochemistry in Mallards from Ottenby

	RRT-PCR (Ct value)		Virus isolation		Immunohistochemistry
Individual	Oropharyngeal	Cloacal	Oropharyngeal	Cloacal	Respiratory	Gastrointestinal	Number of cells
138909	Neg^a	Neg	NA^b	NA	Neg	Pos^c	Cloacal bursa: 56 cells
138920	33.96	36.91	H4N6 E2^d	Neg	Neg	Neg
138964	36.14	33.7	H5N3 E2^d	H5N3 E1^d	Neg	Pos	Jejunum: 2 sections, 99 cells; Colon: 2 sections, 28 cells
138984	36.21	30.71	H4N6 E1^d	Neg	Neg	Pos	Cloacal bursa: 2 sections, 62 cells
139211	33.59	29.34	Neg	Neg	Neg	Neg

^aNeg: not detected.
^bNA: not analysed.
^cPos: detected.
^dPassage number, where E1 is the first passage, E2 is the second passage, and E3 is the third passage.

ISSN: 1297-9716