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BLV Prevalence

BLV in North America

In the 1960s and 1970s, the prevalence of BLV in US and Canadian cattle was approximately 10%. Because BLV-induced tumors (lymphoma) were the only impact recognized at that time, the US and Canadian cattle industries decided that BLV was not sufficiently costly to warrant control. Since that time, the prevalence of BLV in the US has crept up and now nearly 50% of all U.S. dairy cattle are now infected30. According to USDA surveys, 83% of US dairy herds have at least one infected animal, and an estimated 39% of beef cow calf herds have at least one BLV-infected animal.

Prevalence in Select U.S. States and Canadian Provinces:

State/Province

Percentage of Herds Infected

Percentage of Infected Cows within BLV Positive Herds

Michigan

87

23-46

Saskatchewan

89

37

Manitoba

97

61

New Brunswick

77

29

Prince Edward Island

63

17

Nova Scotia

70

16

Alberta

87

27

 

International BLV

At around the same time that North American dairy industries chose not to pursue BLV, many other countries opted to initiate BLV control programs, such that currently 21 countries have successfully eradicated BLV from all their cattle herds. Bovine leukemia virus was eradicated from all cattle in 12 European countries as of 2003, and from 8 additional European countries and New Zealand as of 2011. Additionally, BLV has been eradicated from most regions of Poland, Portugal, and Italy. In Western Australia, BLV has been successfully eradicated from dairy herds, but the government has decided to not attempt eradication of BLV from beef herds, which have a very low prevalence of infected cattle. In these countries, eradication was achieved mainly by testing and culling or segregating positive cattle56.

World prevalence map31

Countries Where BLV is Currently Absent31:

Country

Date of Last Occurrence

Andorra

1994

Chinese Taipei

2006

Cyprus

1995

Czech Republic

2010

Denmark

1990

Egypt

1997

Estonia

2013

Finland

2008

Georgia

1996

Ireland

1999

Kazakhstan

2007

Kyrgyzstan

2008

New Zealand

2008

Norway

2002

Slovenia

2006

South Africa

2012

Spain

1994

Sweden

2007

Switzerland

2005

Tunisia

2005

United Kingdom

1996

 

Countries Where Clinical Disease is Present31:

Argentina, Brazil, Canada, Chile, Colombia, Costa Rica, Dominican Republic, Ecuador, Former Yug. Rep. of Macedonia, Guatemala, Honduras, Israel, Japan, South Korea, Nicaragua, Russia, Ukraine, USA, Uruguay, Uzbekistan

Countries Where BLV is Present, but does not Exhibit Clinical Signs or is Restricted to a Certain Area31:

Australia, France, Greece, Hungary, Italy, Latvia, Lithuania, Mexico, Moldova, Portugal, Germany*

*Germany is officially labeled as BLV free, but has had multiple recent cases.