plague Archives - Prairie Dog Pals

Effects of Deltamethrin Treatment on Small Mammal and Ectoparasite Population Dynamics and Plague Prevalence in a North American Mixed-Grass Prairie System.

January 28, 2019 by PDP

Author information

Department of Biology, University of South Dakota, Vermillion, South Dakota.

Abstract

Sylvatic plague affects many species in North American prairie ecosystems. Deltamethrin is commonly used to manage fleas in potential outbreak areas. Understanding the role of small mammals and their ectoparasites in sylvatic plague maintenance is pertinent to understanding the ecology of plague and its persistence in nature. This study examined the effects of plague management using deltamethrin on communities of small mammals, their flea faunas, and Yersinia pestis prevalence. We trapped small mammals from 2014 to 2016 on the Lower Brule Indian Reservation (LOBR), South Dakota, and analyzed the effects of deltamethrin treatment on small mammal populations, flea loads, and Y. pestis prevalence. We collected higher flea loads from small mammals on sites not treated with deltamethrin (1.10 fleas per animal) than from deltamethrin-treated sites (1.03 fleas per animal). We observed significant negative trends in mean flea load per animal between pre- and post-treatment collections. We detected no significant effects of deltamethrin treatment on animal captures pre- and post-treatment, but observed significant differences in animal captures by experimental unit. We detected no serological evidence for the presence of Y. pestis antibodies in small mammals and 1.2% Y. pestis prevalence across all sampled fleas. Although there is little overlap in the species of fleas infesting small mammals and prairie dogs, the occurrence of flea spillover has been documented. In our study, treatment with deltamethrin reduced flea loads on small mammals by up to 49%. Our data suggest that although the efficacy of deltamethrin on the LOBR-a mixed-grass system-may not be as high as that found in a comparable study in a short-grass system, deltamethrin is still a useful tool in the management of plague.

KEYWORDS:

; South Dakota; deltamethrin; fleas; plague management; small mammals

Third cat tests positive for bubonic plague in Wyoming

January 16, 2019 by PDP

For the third time in recent months, a cat has tested positive for bubonic plague in Wyoming, the state’s Department of Health reports. No human cases have been identified, but health officials warn the disease can be passed to people from infected animals.

Evaluation of Five Pulicides to Suppress Fleas on Black-Tailed Prairie Dogs:

January 13, 2019 by PDP

1. Vector Borne Zoonotic Dis. 2019 Jan 8. doi: 10.1089/vbz.2018.2339. [Epub ahead of

print]

Evaluation of Five Pulicides to Suppress Fleas on Black-Tailed Prairie Dogs:

Encouraging Long-Term Results with Systemic 0.005% Fipronil.

Eads DA(1), Biggins DE(2), Bowser J(2), Broerman K(2), Livieri TM(3), Childers

E(4), Dobesh P(5), Griebel RL(5).

Author information:

(1)1 Department of Biology, Colorado State University, Fort Collins, Colorado.

(2)2 U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado.

(3)3 Prairie Wildlife Research, Wellington, Colorado.

(4)4 National Park Service, Badlands National Park, Interior, South Dakota.

(5)5 U.S. Forest Service, Wall, South Dakota.

Plague, a flea-borne disease, hampers efforts to restore populations of

black-footed ferrets (Mustela nigripes), which occupy colonies of prairie dogs

(Cynomys spp.) in North America. Plague is managed by infusing prairie dog

burrows with DeltaDust® 0.05% deltamethrin, a pulicide that kills fleas.

Experiments are needed to identify pulicides that can be used in rotation with

DeltaDust for integrated plague management. In South Dakota, USA, we tested the

efficacy of four pulicide dusts when applied at a rate of 8

g per burrow on

colonies of black-tailed prairie dogs (Cynomys ludovicianus): Sevin® 5% carbaryl;

Dusta-cide® 6% malathion; Alpine® 0.25% dinotefuran with 95% diatomaceous earth;

and Tri-Die® 1% pyrethrum with 40% amorphous silica and 10% piperonyl butoxide.

We also tested systemic 0.005% fipronil, which was distributed as

cup of laced

grain per burrow. We sampled prairie dogs on 3294 occasions and detected 10,041

fleas. Sevin and Dusta-cide suppressed fleas but only for 1 month. Neither Alpine

nor Tri-Die had any noticeable, consistent effect on fleas. Fipronil suppressed

fleas by 97-100% for 3 months. The residual effect of fipronil persisted for

∼

months. Efficacy of fipronil seems comparable with DeltaDust, which exhibited a

residual effect for

∼

10 months in prior studies. Continued research is needed to

optimize fipronil treatments for plague management on prairie dog colonies.

DOI: 10.1089/vbz.2018.2339

PMID: 30620249

https://www.ncbi.nlm.nih.gov/portal/utils/file_backend.cgi?Db=p

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Parasitism of Black-Tailed Prairie Dogs by Linognathoides cynomyis (Phthiraptera: Polyplacidae).

September 22, 2018 by PDP

Abstract

The following study investigates louse parasitism of black-tailed prairie dogs (Cynomys ludovicianus (Ord, Rodentia: Sciuridae)) on 20 plots at 13 colonies in the short-grass prairie of New Mexico, USA, June-August, 2011-2012. Among 124 lice collected from 537 prairie dogs during 1,207 sampling events in which anesthetized animals were combed for ectoparasites, all of the lice were identified as Linognathoides cynomyis (Kim, Phthiraptera: Polyplacidae). Data were analyzed under an information-theoretic approach to identify factors predicting louse parasitism. Lice were most prevalent on plots with high densities of prairie dogs. At the scale of hosts, lice were most abundant on prairie dogs in poor body condition (with low mass:foot ratios) and prairie dogs harboring large numbers of fleas (Siphonaptera, mostly Oropsylla hirsuta (Baker, Siphonaptera: Ceratophyllidae) and Pulex simulans (Baker,Siphonaptera: Pulicidae)). Lice have been implicated as supplemental vectors of the primarily flea-borne bacterium Yersinia pestis (Yersin, Enterobacteriales: Yersiniaceae), a re-emerging pathogen that causes sylvatic plague in prairie dog populations. Coparasitism by lice and fleas, as found herein, might enhance plague transmission. L. cynomyis deserves attention in this context.

4,000-year-old genomes point to origins of bubonic plague

June 14, 2018 by PDP

Geneticists are a step closer to understanding how plague evolved into one of the great scourges of human history. Yersinia pestis, the bacterium that causes bubonic plague, spreads through the bites of infected fleas. In the flea’s gut, plague bacteria multiply until a mass of bacteria blocks the passage to the flea’s stomach. The starving flea bites a host and feeds frantically, but since it can’t swallow its meal, it ends up regurgitating blood and bacteria back into its prey’s bloodstream, spreading the disease to a new host.