Plague Research Today is a free monthly online journal that collates and summarizes the latest research about Plague, including details on bubonic plague, yersinia pestis, infection, types, treatment.

Oropsylla hirsuta (Siphonaptera: Ceratophyllidae) Can Support Plague Epizootics in Black-Tailed Prairie Dogs (Cynomys ludovicianus) by Early-Phase Transmission of Yersinia pestis.

Wilder AP, Eisen RJ, Bearden SW, Montenieri JA, Gage KL, Antolin MF

Bacterial Diseases Branch, Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado., Department of Biology, Colorado State University, Fort Collins, Colorado.

Plague, caused by the bacterium Yersinia pestis, often leads to rapid decimation of black-tailed prairie dog colonies. Flea-borne transmission of Y. pestis has been thought to occur primarily via blocked fleas, and therefore studies of vector efficiency have focused on the period when blockage is expected to occur (>/=5 days post-infection [p.i.]). Oropsylla hirsuta, a prairie dog flea, rarely blocks and transmission is inefficient >/=5 days p.i.; thus, this flea has been considered incapable of explaining rapid dissemination of Y. pestis among prairie dogs. By infecting wild-caught fleas with Y. pestis and exposing naïve mice to groups of fleas at 24, 48, 72, and 96 h p.i., we examined the early-phase (1-4 days p.i.) efficiency of O. hirsuta to transmit Y. pestis to hosts and showed that O. hirsuta is a considerably more efficient vector at this largely overlooked stage (5.19% of fleas transmit Y. pestis at 24 h p.i.) than at later stages. Using a model of vectorial capacity, we suggest that this level of transmission can support plague at an enzootic level in a population when flea loads are within the average observed for black-tailed prairie dogs in nature. Shared burrows and sociality of prairie dogs could lead to accumulation of fleas when host population is reduced as a result of the disease, enabling epizootic spread of plague among prairie dogs.

Published 5 May 2008 in Vector Borne Zoonotic Dis.
Full-text of this article is available online (may require subscription).

Articles on Plague published 2 May 2008:

A missense mutation causes aspartase deficiency in Yersinia pestis.   Microbiology, 154: 1271-80.

It is established that cells of Yersinia pestis, the causative agent of bubonic plague, excrete l-aspartic acid at the expense of exogenous l-glutamic acid during expression of the low-calcium response. Results of enzymic analysis provided here suggest that a previously defined deficiency of aspartase (AspA) accounts for this phenomenon rather than an elevated oxaloacetate pool. The only known distinction between most sequenced isolates of aspA from Y. pestis and the active gene in Yersinia ... [Abstract] [Full-text]

Articles on Plague published 1 May 2008:

No Evidence of Deer Mouse Involvement in Plague (Yersinia pestis) Epizootics in Prairie Dogs.   Vector Borne Zoonotic Dis.

Plague, the disease caused by the bacterium Yersinia pestis, can have devastating impacts on black-tailed prairie dog (Cynomys ludovicianus) colonies. One suggested mechanism behind sporadic prairie dog die-offs involves an alternative mammal host, such as the deer mouse (Peromyscus maniculatus), which often inhabits prairie dog colonies. We examined the flea populations of deer mice to investigate the potential of flea-borne transmission of plague between deer mice and prairie dogs in northern ... [Abstract] [Full-text]

Articles on Plague published 25 April 2008:

Erectile dysfunction and Peyronie's disease in patient with retroperitoenal fibrosis.   Int Urol Nephrol.

OBJECTIVE: The aim of this study is to determine the sexual dysfunction in patient with retroperitoneal fibrosis (RPF) and also we explored probability of Peyronie's disease (PD) in this patient group and to compare this with the controls. MATERIALS AND METHODS: Ten of 17 male RPF patients formed the basis of this study. Patient's age, concomitant diseases were recorded. The diagnosis of PD was based on a palpable penile plaque or acquired penile curvature. Age-matched 88 patients who were ... [Abstract] [Full-text]

Articles on Plague published 21 April 2008:

Yersinia pestis caf1 variants and the limits of plague vaccine protection.   Infect Immun, 76(5): 2025-36.

Yersinia pestis, the highly virulent agent of plague, is a biological weapon. Strategies that prevent plague have been sought for centuries, and immunization with live, attenuated (nonpigmented) strains or subunit vaccines with F1 (Caf1) antigen is considered effective. We show here that immunization with live, attenuated strains generates plague-protective immunity and humoral immune responses against F1 pilus antigen and LcrV. Y. pestis variants lacking caf1 (F1 pili) are not only fully ... [Abstract] [Full-text]

Different genes govern Yersinia pestis pathogenicity in Caenorhabditis elegans and human lice.   Microb Pathog, 44(5): 435-7.

To assess the role of virulence factors identified in Caenorhabditis elegans in the transmission of plague by lice, we infected 100 lice by feeding them on rabbits and made them bacteremic; the rabbits had been intravenously inoculated with 10(9) CFU of six different mutant Yersinia pestis strains of lower pathogenicity for C. elegans, obtained from the KIM5 strain. This strain lacks genes used for biofilm formation. High mortality rates were observed in all lice, which excreted viable bacteria ... [Abstract] [Full-text]

Articles on Plague published 14 April 2008:

Infectious agents of bioterrorism: a review for emergency physicians.   Emerg Med Clin North Am, 26(2): 517-47.

The terrorist attacks on the United States in 2001 and the anthrax release soon after brought the issue of bioterrorism to the forefront in the medical community. Bioterrorism is the use of a biologic weapon to create terror and panic. Biologic weapons, or bioweapons, can be bacteria, fungi, viruses, or biologic toxins. Because the emergency department represents the front line of defense for the recognition of agents of bioterrorism, it is essential that emergency physicians have the ability ... [Abstract] [Full-text]

Articles on Plague published 10 April 2008:

Characterisation of Yersinia pestis isolates from natural foci of plague in the Republic of Georgia, and their relationship to Y. pestis isolates from other countries.   Clin Microbiol Infect, 14(5): 429-36.

Forty Yersinia pestis isolates from endemic foci of plague in the Republic of Georgia, and six Y. pestis isolates from neighbouring former Soviet Union countries, were analysed for their biochemical and phenotypic properties, and their genetic relatedness was compared with Y. pestis strains KIM and CO92 by pulsed-field gel electrophoresis (PFGE). In addition, 11 Y. pestis isolates from the USA, together with published nucleotide sequences from Y. pestis strains KIM, CO92 and 91001, were ... [Abstract] [Full-text]

Articles on Plague published 9 April 2008:

Uniquely insidious: Yersinia pestis biofilms.   Trends Microbiol, 16(4): 158-64.

Bubonic plague, one of history's deadliest infections, is transmitted by fleas infected with Yersinia pestis. The bacteria can starve fleas by blocking their digestive tracts, which stimulates the insects to bite repeatedly and thereby infect new hosts. Direct examination of infected fleas, aided by in vitro studies and experiments with the nematode Caenorhabditis elegans, have established that Y. pestis forms a biofilm in the insect. The extracellular matrix of the biofilm seems to contain a ... [Abstract] [Full-text]

© 2005-2008 Plague Research Today. All Rights Reserved.