Cowpox virus transmission from pet rats to humans, France

Abstract

In early 2009, four human cases of cowpox virus cutaneous infection in northern France, resulting from direct contact with infected pet rats (Rattus norvegicus), were studied. Pet rats, originating from the same pet store, were shown to be infected by a unique virus strain. Infection was then transmitted to humans who purchased or had contact with pet rats.

Figure 1

Cowpox virus infection in 3 persons in northern France caused by transmission from infected pet rats. Cutaneous lesions caused by cowpox virus are shown in patient 1 (A), patient 3 (B) and patient 4 (C, D). The 2 latter patients had lymphangitis associated with the local lesion. Panel C was obtained on January 30, 2009, panel D on February 6, 2009. Negative-staining electron microscopy showed mulberry forms with conspicuous but short, randomly arranged surface tubules (E) and capsule forms with deeper stain penetration (F), both highly suggestive of poxvirus. Scale bar for panels E and F = 100 nm.

Figure 2

Phylogenetic tree based on nucleotide sequences in the hemagglutinin gene. Sequence information corresponds to virus acronym/strain/GenBank accession number. Phylogenetic study was conducted using MEGA software version 4.0 (www.megasoftware.net). Genetic distances were calculated with the pairwise distance method. Phylogenetic tree were constructed with the neighbor-joining method. CPXV, cowpox virus; ECTV, ectromelia virus; VARV, variola virus; CMLV, camelpox virus; VACV, vaccinia virus; HSPV, horsepox virus; MPXV, monkeypox virus. Scale bar indicates genetic diversity at the nucleotide level.