Highly pathogenic avian influenza virus (H5N1) infection in red foxes fed infected bird carcasses. Emerging Infectious Diseases

• Main Authors: Leslie A. Reperant, Geert Van Amerongen, Guus F. Rimmelzwaan, Andrew P. Dobson, Albert D. M. E. Osterhaus, Thijs Kuiken
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2008
• Subjects: Canis lupus; harbor seal; Phoca vitulina
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.189.1987; http://www.cdc.gov/eid/content/14/12/pdfs/1835.pdf

Eating infected wild birds may put wild carnivores at high risk for infection with highly pathogenic avian infl u-enza (HPAI) virus (H5N1). To determine whether red foxes (Vulpes vulpes) are susceptible to infection with HPAI virus (H5N1), we infected 3 foxes intratracheally. They excreted virus pharyngeally for 3–7 days at peak titers of 10 3.5 –10 5.2 median tissue culture infective dose (TCID 50) per mL and had severe pneumonia, myocarditis, and encephalitis. To determine whether foxes can become infected by the presumed natural route, we fed infected bird carcasses to 3 other red foxes. These foxes excreted virus pharyngeally for 3–5 days at peak titers of 10 4.2 –10 4.5 TCID 50 /mL, but only mild or no pneumonia developed. This study demonstrates that red foxes fed bird carcasses infected with HPAI virus (H5N1) can excrete virus while remaining free of severe disease, thereby potentially playing a role in virus dispersal. Influenza A viruses rarely infect species of the order Carnivora. However, since 2003, highly pathogenic avian influenza (HPAI) viruses of subtype H5N1 have infected a wide range of carnivore species. Within the past 30 years, and before the emergence of HPAI viruses (H5N1), 5 documented outbreaks of influenza virus infections occurred in 2 carnivore species—the harbor seal (Phoca vitulina) (1–4), and the American mink (Mustela vison) (5). In both species, the infection resulted in respiratory disease. In addition, influenza virus infection has been detected by virus culture or serologic examination in other carnivores, namely, domestic dogs (Canis lupus familiaris) (6,7), domestic cats (Felis catus) (8,9), and bears kept in captivity (species