Experimental Plague in the California Ground Squirrel

Williams, J. E.; Moussa, M. A.; Cavanaugh, Dan C.

doi:10.1093/infdis/140.4.618

Cited by 18 publications

(13 citation statements)

References 12 publications

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“…The results on reinoculation of T. brantsii also confirmed the results of previous authors (Chen & Meyer, 1974;Williams, Moussa & Cavanaugh, 1979); animals which survive challenge with low doses of Y. pestis without seroconversion remain susceptible to the organism on subsequent reinoculation. Of the five T. brantsii which remained seronegative after initial exposure, one died and four seroconverted after a second challenge with 2 x 103 organisms.…”

Section: Discussionsupporting

confidence: 89%

“…Chen & Meyer (1974) reported a variable duration of antibody response in experimentally infected Rattus spp. while Williams, Moussa & Cavanaugh (1979) noted that plague antibody titres in experimentally infected C. beecheyi remained unchanged from 6-42 weeks post infection.…”

Section: Discussionmentioning

confidence: 93%

“…Williams, Moussa & Cavanaugh (1979) reported that the response of C. beecheyi to experimental infection with a range of plague organisms up to the maximum (2-4 x 104) of a single flea bite (Burroughs, 1947) was that 280 of the squirrels died, 190 seroconverted and the remaining 53 % survived without seroconversion. Our results for the experimental plague infection of T. leucoqaster (below 2-4 x 104 bacilli) revealed similar ratios of 10 % mortality, 330 seroconversion and 570 survival without seroconversion.…”

Section: Discussionmentioning

confidence: 99%

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Experimental plague infection in South African wild rodents

Shepherd

Leman

Hummitzsch

1986

J. Hyg.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

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Experimental plague infection in South African wild rodents

Shepherd

Leman

Hummitzsch

1986

J. Hyg.

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“…The larger doses given to rats may explain the higher rate of seroconversions in the rats than in the other species, which succumbed to the larger doses of bacteria. This dosage relationship to seroconversion has been documented also by Williams et al (19) in parenteral inoculations of ground squirrels.…”

Section: H After Ig Inoculation Of 8 X 105 Organismssupporting

confidence: 72%

Experimental Yersinia pestis infection in rodents after intragastric inoculation and ingestion of bacteria

Butler¹,

Fu²,

Furman³

et al. 1982

Infect Immun

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To clarify the pathogenesis of oral plague infection, we studied the susceptibility of three species of rodents to intragastric inoculation of Yersinia pestis, described the pathology and progression of infection, and measured antibody responses to fraction IA antigen of Y. pestis. The 50% lethal doses of bacteria by intragastric inoculation for Mus musculus, Zygodontomys pixuna, and Rattus rattus were log10 = 6.32, 5.46, and 9.62, respectively, which were at least 1,000-fold higher than the values obtained by subcutaneous inoculation. M. musculus was shown to be susceptible to lethal infection also when bacteria were ingested in drinking water. Microscopic pathology was consistent with heavy systemic infection. Quantitative cultures of tissues at different times after intragastric inoculation revealed that infections of blood, liver, and spleen preceded infections of Peyer's patches and mesenteric lymph nodes. Stool cultures were negative. The strain of Y. pestis used for inoculation was killed when exposed to a buffered solution at pH less than or equal to 3. Antibody responses were observed in some of the surviving rodents after intragastric challenge. These results showed that Y. pestis was an effective oral pathogen that produced fatal systemic infections and self-limited infections with immunity but did not produce enteric pathology or lead to fecal excretion of bacteria.

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“…The California ground squirrel, the major host of O . montana , reportedly has an ID 50 of >250 CFU [37]. Based on the previous reports that O .…”

Section: Discussionmentioning

confidence: 99%

Comparative Ability of Oropsylla montana and Xenopsylla cheopis Fleas to Transmit Yersinia pestis by Two Different Mechanisms

et al. 2017

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BackgroundTransmission of Yersinia pestis by flea bite can occur by two mechanisms. After taking a blood meal from a bacteremic mammal, fleas have the potential to transmit the very next time they feed. This early-phase transmission resembles mechanical transmission in some respects, but the mechanism is unknown. Thereafter, transmission occurs after Yersinia pestis forms a biofilm in the proventricular valve in the flea foregut. The biofilm can impede and sometimes completely block the ingestion of blood, resulting in regurgitative transmission of bacteria into the bite site. In this study, we compared the relative efficiency of the two modes of transmission for Xenopsylla cheopis, a flea known to become completely blocked at a high rate, and Oropsylla montana, a flea that has been considered to rarely develop proventricular blockage.Methodology/Principal findingsFleas that took an infectious blood meal containing Y. pestis were maintained and monitored for four weeks for infection and proventricular blockage. The number of Y. pestis transmitted by groups of fleas by the two modes of transmission was also determined. O. montana readily developed complete proventricular blockage, and large numbers of Y. pestis were transmitted by that mechanism both by it and by X. cheopis, a flea known to block at a high rate. In contrast, few bacteria were transmitted in the early phase by either species.ConclusionsA model system incorporating standardized experimental conditions and viability controls was developed to more reliably compare the infection, proventricular blockage and transmission dynamics of different flea vectors, and was used to resolve a long-standing uncertainty concerning the vector competence of O. montana. Both X. cheopis and O. montana are fully capable of transmitting Y. pestis by the proventricular biofilm-dependent mechanism.

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Experimental Plague in the California Ground Squirrel

Cited by 18 publications

References 12 publications

Experimental plague infection in South African wild rodents

Experimental plague infection in South African wild rodents

Experimental Yersinia pestis infection in rodents after intragastric inoculation and ingestion of bacteria

Comparative Ability of Oropsylla montana and Xenopsylla cheopis Fleas to Transmit Yersinia pestis by Two Different Mechanisms

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