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PLoS Neglected Tropical Diseases Aug 2018The Qinghai-Tibet plateau is a natural plague focus and is the largest such focus in China. In this area, while Marmota himalayana is the primary host, a total of 18...
The Qinghai-Tibet plateau is a natural plague focus and is the largest such focus in China. In this area, while Marmota himalayana is the primary host, a total of 18 human plague outbreaks associated with Tibetan sheep (78 cases with 47 deaths) have been reported on the Qinghai-Tibet plateau since 1956. All of the index infectious cases had an exposure history of slaughtering or skinning diseased or dead Tibetan sheep. In this study, we sequenced and compared 38 strains of Yersinia pestis isolated from different hosts, including humans, Tibetan sheep, and M. himalayana. Phylogenetic relationships were reconstructed based on genome-wide single-nucleotide polymorphisms identified from our isolates and reference strains. The phylogenetic relationships illustrated in our study, together with the finding that the Tibetan sheep plague clearly lagged behind the M. himalayana plague, and a previous study that identified the Tibetan sheep as a plague reservoir with high susceptibility and moderate sensitivity, indicated that the human plague was transmitted from Tibetan sheep, while the Tibetan sheep plague originated from marmots. Tibetan sheep may encounter this infection by contact with dead rodents or through being bitten by fleas originating from M. himalayana during local epizootics.
Topics: Animals; DNA, Bacterial; Disease Reservoirs; Genome, Bacterial; Humans; Marmota; Phylogeny; Plague; Polymorphism, Single Nucleotide; Sheep; Sheep Diseases; Yersinia pestis; Zoonoses
PubMed: 30114220
DOI: 10.1371/journal.pntd.0006635 -
BMC Infectious Diseases Jul 2014Qinghai-Tibetan Plateau of China is known to be the plague endemic region where marmot (Marmota himalayana) is the primary host. Human plague cases are relatively low...
BACKGROUND
Qinghai-Tibetan Plateau of China is known to be the plague endemic region where marmot (Marmota himalayana) is the primary host. Human plague cases are relatively low incidence but high mortality, which presents unique surveillance and public health challenges, because early detection through surveillance may not always be feasible and infrequent clinical cases may be misdiagnosed.
METHODS
Based on plague surveillance data and environmental variables, Maxent was applied to model the presence probability of plague host. 75% occurrence points were randomly selected for training model, and the rest 25% points were used for model test and validation. Maxent model performance was measured as test gain and test AUC. The optimal probability cut-off value was chosen by maximizing training sensitivity and specificity simultaneously.
RESULTS
We used field surveillance data in an ecological niche modeling (ENM) framework to depict spatial distribution of natural foci of plague in Qinghai-Tibetan Plateau. Most human-inhabited areas at risk of exposure to enzootic plague are distributed in the east and south of the Plateau. Elevation, temperature of land surface and normalized difference vegetation index play a large part in determining the distribution of the enzootic plague.
CONCLUSIONS
This study provided a more detailed view of spatial pattern of enzootic plague and human-inhabited areas at risk of plague. The maps could help public health authorities decide where to perform plague surveillance and take preventive measures in Qinghai-Tibetan Plateau.
Topics: Humans; Models, Statistical; Plague; Population Surveillance; Risk Factors; Tibet
PubMed: 25011940
DOI: 10.1186/1471-2334-14-382 -
Journal of Vector Ecology : Journal of... Jun 2019Plague is a flea-borne disease of mammalian hosts. On the grasslands of western North America, plague stifles populations of Cynomys spp. prairie dogs (PDs). To manage...
Plague is a flea-borne disease of mammalian hosts. On the grasslands of western North America, plague stifles populations of Cynomys spp. prairie dogs (PDs). To manage plague, PD burrows are treated with 0.05% deltamethrin dust that can suppress flea numbers and plague transmission. Here, we evaluate the degree and duration of deltamethrin flea control with three PD species at six sites across four U.S. states. Data were simultaneously collected at paired plots. Burrows from one randomly assigned member of each pair were treated with deltamethrin; non-treated plots served as experimental baselines. Flea control was strong ≤two months after treatment, remained moderate one year later, and was statistically detectable for up to two years at some sites. Flea abundance was lower in plots with higher rates of deltamethrin application. After burrow treatments, flea abundance increased over time, reaching >one per PD within 255 to 352 days. Nevertheless, annual treatments of burrows with deltamethrin provided PDs with substantial protection against plague. Even so, deltamethrin should be further evaluated and combined with other tools under an integrated approach to plague management. Integrated plague management should help to conserve PDs and species that associate with them, including the endangered black-footed ferret (Mustela nigripes).
Topics: Animals; Flea Infestations; Insecticides; Nitriles; Plague; Pyrethrins; Risk Factors; Sciuridae; United States
PubMed: 31124240
DOI: 10.1111/jvec.12327 -
Journal of Medical Entomology Nov 2015Early-phase transmission (EPT) of Yersinia pestis by unblocked fleas is a well-documented, replicable phenomenon with poorly defined mechanisms. We review evidence... (Review)
Review
Early-phase transmission (EPT) of Yersinia pestis by unblocked fleas is a well-documented, replicable phenomenon with poorly defined mechanisms. We review evidence demonstrating EPT and current knowledge on its biological and biomechanical processes. We discuss the importance of EPT in the epizootic spread of Y. pestis and its role in the maintenance of plague bacteria in nature. We further address the role of EPT in the epidemiology of plague.
Topics: Animals; Disease Outbreaks; Humans; Insect Vectors; Plague; Siphonaptera; Yersinia pestis
PubMed: 26336267
DOI: 10.1093/jme/tjv128 -
Revista Da Sociedade Brasileira de... 2020
Topics: Animals; Brazil; Disease Notification; Humans; Plague; Risk Factors; Yersinia pestis
PubMed: 32187330
DOI: 10.1590/0037-8682-0136-2019 -
The Indian Medical Gazette Nov 1946
Topics: Humans; Meningitis; Plague
PubMed: 20287034
DOI: No ID Found -
MMWR. Morbidity and Mortality Weekly... Mar 2020Plague, an acute zoonosis caused by Yersinia pestis, is endemic in the West Nile region of northwestern Uganda and neighboring northeastern Democratic Republic of the...
Plague, an acute zoonosis caused by Yersinia pestis, is endemic in the West Nile region of northwestern Uganda and neighboring northeastern Democratic Republic of the Congo (DRC) (1-4). The illness manifests in multiple clinical forms, including bubonic and pneumonic plague. Pneumonic plague is rare, rapidly fatal, and transmissible from person to person via respiratory droplets. On March 4, 2019, a patient with suspected pneumonic plague was hospitalized in West Nile, Uganda, 4 days after caring for her sister, who had come to Uganda from DRC and died shortly thereafter, and 2 days after area officials received a message from a clinic in DRC warning of possible plague. The West Nile-based Uganda Virus Research Institute (UVRI) plague program, together with local health officials, commenced a multipronged response to suspected person-to-person transmission of pneumonic plague, including contact tracing, prophylaxis, and education. Plague was laboratory-confirmed, and no additional transmission occurred in Uganda. This event transpired in the context of heightened awareness of cross-border disease spread caused by ongoing Ebola virus disease transmission in DRC, approximately 400 km to the south. Building expertise in areas of plague endemicity can provide the rapid detection and effective response needed to mitigate epidemic spread and minimize mortality. Cross-border agreements can improve ability to respond effectively.
Topics: Adult; Democratic Republic of the Congo; Epidemics; Female; Humans; Plague; Public Health Practice; Travel-Related Illness; Uganda; Young Adult
PubMed: 32134908
DOI: 10.15585/mmwr.mm6909a5 -
Vector Borne and Zoonotic Diseases... Aug 2022In April 2021, a plague outbreak was identified within one family shortly after emerging from hibernation, during plague surveillance in the plague foci of the...
In April 2021, a plague outbreak was identified within one family shortly after emerging from hibernation, during plague surveillance in the plague foci of the Qinghai-Tibet Plateau. A total of five marmots were found dead of near the same burrow; one live marmot was positive of fraction 1 (F1) antibody. Comparative genome analysis shows that few single nucleotide polymorphisms were detected among the nine strains, indicating the same origin of the outbreak. The survived marmot shows a high titer of F1 antibody, higher than the mean titer of all marmots during the 2021 monitoring period ( = 391.00, = 2.81, < 0.01). Marmots live with during hibernation when the pathogen is inhibited by hypothermia. But they wake up during or just after hibernation with body temperature rising to 37°C, when goes through optimal growth temperature, increases virulence, and causes death in marmots. A previous report has shown human plague cases caused by excavating marmots during winter; combined, this study shows the high risk of hibernation marmot carrying . This analysis provides new insights into the transmission of the highly virulent in plague foci and drives further effort upon plague control during hibernation.
Topics: Animals; Disease Outbreaks; Hibernation; Humans; Marmota; Plague; Rodent Diseases; Yersinia pestis
PubMed: 35787155
DOI: 10.1089/vbz.2022.0010 -
Proceedings. Biological Sciences Apr 2014Currently, large-scale transmissions of infectious diseases are becoming more closely associated with accelerated globalization and climate change, but quantitative...
Currently, large-scale transmissions of infectious diseases are becoming more closely associated with accelerated globalization and climate change, but quantitative analyses are still rare. By using an extensive dataset consisting of date and location of cases for the third plague pandemic from 1772 to 1964 in China and a novel method (nearest neighbour approach) which deals with both short- and long-distance transmissions, we found the presence of major roads, rivers and coastline accelerated the spread of plague and shaped the transmission patterns. We found that plague spread velocity was positively associated with wet conditions (measured by an index of drought and flood events) in China, probably due to flood-driven transmission by people or rodents. Our study provides new insights on transmission patterns and possible mechanisms behind variability in transmission speed, with implications for prevention and control measures. The methodology may also be applicable to studies of disease dynamics or species movement in other systems.
Topics: China; Climate; Climate Change; Communicable Diseases, Emerging; Droughts; Floods; Humans; Pandemics; Plague
PubMed: 24523275
DOI: 10.1098/rspb.2013.3159 -
Revista Da Sociedade Brasileira de... 2017In Brazil, the plague is established in several foci located mainly in the northeastern part of the country, where it alternates between active and quiescent periods....
INTRODUCTION
In Brazil, the plague is established in several foci located mainly in the northeastern part of the country, where it alternates between active and quiescent periods. These foci in the State of Ceará have high epidemiological importance. In addition to other plague detection activities, plague areas can be monitored through serological surveys of dogs and cats (domestic carnivores), which, following feeding on plague-infected rodents, can develop mild to severe forms of the disease and produce long-lasting antibodies. This study aimed to characterize the circulation dynamics and spatial distribution of Yersinia pestis antibodies in dogs and cats in plague foci areas of Ceará.
METHODS
An ecological study was conducted to analyze the temporal series and spatial distribution of secondary data obtained from domestic carnivore serum surveillance in Ceará's plague areas from 1990 to 2014.
RESULTS
Joinpoint analysis revealed that the overall trend was a reduction in antibody-positive animals. The mean proportion of antibody-positivity during the whole study period was 1.5% (3,023/203,311) for dogs, and 0.7% (426/61,135) for cats, with more than 4% antibody-positivity in dogs in 1997 and 2002. Antibody titers ranging from 1/16 to 1/64 were frequent. Despite fluctuations and a significant reduction, in recent years, there were antibody-positive animals annually throughout the study period, and the localities containing antibody-positive animals increased in number.
CONCLUSION
Yersinia pestis is actively circulating in the study areas, posing a danger to the human population.
Topics: Animals; Antibodies, Bacterial; Brazil; Cat Diseases; Cats; Dog Diseases; Dogs; Plague; Population Surveillance; Prevalence; Seroepidemiologic Studies; Spatio-Temporal Analysis; Yersinia pestis
PubMed: 29340453
DOI: 10.1590/0037-8682-0278-2017