Phylogeography, phylodynamics and transmission chains of bovine viral diarrhea virus subtype 1f in Northern Italy.
Bovine viral diarrhea virus (BVDV) type 1 in Italy is characterized by high genetic diversity, with at least 20 subtypes. Subtype 1f is endemic in a restricted geographic area, meaning that it has local distribution. We investigated the population dynamics of BVDV-1f in Northern Italy and characterized the transmission chains of a subset of samples from Piedmont and Aosta Valley regions. A total of 51 samples from 1966 to 2013 were considered and 5' UTR sequences were used for phylogeography. A subset of 12 samples was selected for Npro gene sequencing and further characterization of the transmission chains using both molecular and epidemiological data. Phylogeography estimated the root of BVDV-1f tree in Veneto in 1965. Four significant subclades included sequences clustering by region: Lombardy (n=3), Lombardy and Emilia-Romagna (n=7), Piedmont (n=17), Piedmont and Aosta Valley (n=21). The Piedmont-only subclade has a ladder-like branching structure, while the Piedmont and Aosta Valley subclade has a nearly complete binary structure. In the subset, the outbreak reconstruction identified one sample from Piedmont as the most probable source of infection for the Aosta Valley cases. An ad hoc questionnaire submitted to public veterinarians revealed connections between sampled and non-sampled farms by means of trades, exhibitions and markets. According to the phylogeography, BVDV-1f moved westward, entering from Veneto, and spreading to Lombardy and Emilia-Romagna in the early 1990s, and finally to Piedmont and Aosta Valley in the first decade of 2000s. Both phylogeographic analyses on the whole dataset and on the selection of Npro dataset pointed out that subtype 1f entered Aosta Valley from Piedmont. The integration of molecular and epidemiological data revealed connections between farms, and such approach should be considered in any control plan. In Aosta Valley, the study showed that BVDV1f can be controlled only monitoring the introduction of cattle from Piedmont region.
Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle D'Aosta, Via Bologna 148, 10154 Turin, Italy. Electronic address: francesco.cerutti@izsto.it.
Francesco
F
Cerutti
Department of Veterinary Medicine, University of Milan, Via Celoria 10, 20133 Milan, Italy. Electronic address: camilla.luzzago@unimi.it.
Camilla
C
Luzzago
Department of Veterinary Medicine, University of Milan, Via Celoria 10, 20133 Milan, Italy. Electronic address: stefania.lauzi@unimi.it.
Stefania
S
Lauzi
Department of Clinical Sciences "Luigi Sacco", Section of Infectious Diseases, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy. Electronic address: erika.ebranati@unimi.it.
Erika
E
Ebranati
Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle D'Aosta, Via Bologna 148, 10154 Turin, Italy. Electronic address: claudio.caruso@izsto.it.
Claudio
C
Caruso
Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle D'Aosta, Via Bologna 148, 10154 Turin, Italy. Electronic address: loretta.masoero@izsto.it.
Loretta
L
Masoero
Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 9, 25124 Brescia, Italy. Electronic address: anamaria.morenomartin@izsler.it.
Ana
A
Moreno
Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle D'Aosta, Via Bologna 148, 10154 Turin, Italy. Electronic address: pierluigi.acutis@izsto.it.
Pier Luigi
PL
Acutis
Department of Clinical Sciences "Luigi Sacco", Section of Infectious Diseases, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy. Electronic address: gianguglielmo.zehender@unimi.it.
Gianguglielmo
G
Zehender
Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle D'Aosta, Via Bologna 148, 10154 Turin, Italy. Electronic address: simone.peletto@izsto.it.
Simone
S
Peletto
D000818:Animals; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000453:epidemiology / Q000635:transmission* / Q000821:virology*; D002417:Cattle / Q000821:virology*; D030241:Diarrhea Virus 1, Bovine Viral / Q000145:classification* / Q000235:genetics*; D007558:Italy / Q000453:epidemiology; D017720:Molecular Epidemiology; D010802:Phylogeny; D058974:Phylogeography
BVDV; Italy; Molecular epidemiology; Phylodynamics; Phylogeography; Transmission chain