Orthopoxvirus variola infection of Cynomys ludovicianus (North American Black tailed prairie dog)
ABSTRACT Since the eradication of Smallpox, researchers have attempted to study Orthopoxvirus pathogenesis and immunity in animal models in order to correlate results human smallpox. A solely human pathogen, Orthopoxvirus variola fails to produce authentic smallpox illness in any other animal species tested to date. In 2003, an outbreak in the USA of Orthopoxvirus monkeypox, revealed the susceptibility of the North American black-tailed prairie dog (Cynomys ludovicianus) to infection and fulminate disease. Prairie dogs infected with Orthopoxvirus monkeypox present with a clinical scenario similar to ordinary smallpox, including prodrome, rash, and high mortality. This study examines if Black-tailed prairie dogs can become infected with O. variola and serve as a surrogate model for the study of human smallpox disease. Substantive evidence of infection is found in immunological seroconversion of animals to either intranasal or intradermal challenges with O. variola, but in the absence of overt illness.
- [Show abstract] [Hide abstract]
ABSTRACT: We developed a multiplex polymerase chain reaction (PCR) assay that simultaneously detects three types of flea-associated microorganisms. Targets for the assay were sequences encoding portions of the gltA, a 17-kDa antigen, and pla genes of Bartonella spp. Strong et al., Rickettsia spp. da Rocha-Lima, and Yersinia pestis Yersin, respectively. A total of 260 flea samples containing bloodmeal remnants were analyzed from fleas collected from abandoned prairie dog (Cynomys ludovicianus) burrows at the site of an active plague epizootic in Jefferson County, CO. Results indicated that 34 (13.1%) fleas were positive for Bartonella spp., 0 (0%) were positive for Rickettsia spp., and 120 (46.2%) were positive for Y. pestis. Twenty-three (8.8%) of these fleas were coinfected with Bartonella spp. and Y. pestis. A second group of 295 bloodmeal-containing fleas was collected and analyzed from abandoned burrows in Logan County, CO, where a prairie dog die-off had occurred 2-4 mo before the time of sampling. Of these 295 fleas, 7 (2.4%) were positive for Bartonella spp., 0 (0%) were positive for Rickettsia spp., and 46 (15.6%) were positive for Y. pestis. Coinfections were not observed in fleas from the Logan County epizootic site. The multiplex PCR also was used to identify Y. pestis and Bartonella in prairie dog blood and tissues. This report represents the first identification of Bartonella from prairie dogs and their fleas. Prairie dog fleas were tested with PCR, and the Bartonella PCR amplicons produced were sequenced and found to be closely related to similar sequences amplified from Bartonella that had been isolated from prairie dog blood samples. Phylogenetic analyses indicate that the sequences of bartonellae from prairie dogs and prairie dog fleas cluster tightly within a clade that is distinct from those containing other known Bartonella genotypes.Journal of Medical Entomology 06/2003; 40(3):329-37. DOI:10.1603/0022-2585-40.3.329 · 1.82 Impact Factor
- Indian Journal of Medical Sciences 09/1957; 11(8):580-7. · 1.67 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: During May and June 2003, an outbreak of febrile illness with vesiculopustular eruptions occurred among persons in the midwestern United States who had had contact with ill pet prairie dogs obtained through a common distributor. Zoonotic transmission of a bacterial or viral pathogen was suspected. We reviewed medical records, conducted interviews and examinations, and collected blood and tissue samples for analysis from 11 patients and one prairie dog. Histopathological and electron-microscopical examinations, microbiologic cultures, and molecular assays were performed to identify the etiologic agent. The initial Wisconsin cases evaluated in this outbreak occurred in five males and six females ranging in age from 3 to 43 years. All patients reported having direct contact with ill prairie dogs before experiencing a febrile illness with skin eruptions. We found immunohistochemical or ultrastructural evidence of poxvirus infection in skin-lesion tissue from four patients. Monkeypox virus was recovered in cell cultures of seven samples from patients and from the prairie dog. The virus was identified by detection of monkeypox-specific DNA sequences in tissues or isolates from six patients and the prairie dog. Epidemiologic investigation suggested that the prairie dogs had been exposed to at least one species of rodent recently imported into the United States from West Africa. Our investigation documents the isolation and identification of monkeypox virus from humans in the Western Hemisphere. Infection of humans was associated with direct contact with ill prairie dogs that were being kept or sold as pets.New England Journal of Medicine 02/2004; 350(4):342-50. DOI:10.1056/NEJMoa032299 · 54.42 Impact Factor