scholarly journals Vector Tick Transmission Model of Spotted Fever Rickettsiosis

2019 ◽  
Vol 189 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Tais B. Saito ◽  
Jeremy Bechelli ◽  
Claire Smalley ◽  
Shahid Karim ◽  
David H. Walker
Keyword(s):  
Spotted Fever ◽  
Transmission Model ◽  
Vector Tick ◽  
Tick Transmission

scholarly journals Susceptibility of Inbred Mice to Rickettsia parkeri

2012 ◽  
Vol 80 (5) ◽  
pp. 1846-1852 ◽  
Author(s):  
Britton J. Grasperge ◽  
Kathryn E. Reif ◽  
Timothy D. Morgan ◽  
Piyanate Sunyakumthorn ◽  
Joseph Bynog ◽  
...  
Keyword(s):  
Inbred Mice ◽  
Spotted Fever ◽  
Inbred Mouse ◽  
Transmission Model ◽  
Mouse Strains ◽  
Spotted Fever Group ◽  
Limited Information ◽  
Rickettsia Parkeri ◽  
Content Type ◽  
Boutonneuse Fever

ABSTRACTRickettsia parkeri, a member of the spotted fever groupRickettsia, is the causative agent of American boutonneuse fever in humans. Despite the increased recognition of human cases, limited information is available regarding the infection of invertebrate and vertebrate hosts for this emerging tick-borne disease. Toward the development of a viable transmission model and to further characterize the pathology associated withR. parkeriinfection, inbred mouse strains (A/J, BALB/c, C3H/HeJ, and C3H/HeN) were intravenously and intradermally inoculated with 105low-passage-numberR. parkeri(Portsmouth strain), and infection, gross pathology, and histopathology were scored. Additionally, a quantitative real-time PCR (qPCR) was performed to estimate rickettsial load in heart, lung, spleen, and liver tissues of infected mice at 19 days postinoculation. Of the A/J, BALB/c, and C3H/HeN mice, none displayed universal pathology consistent with sustained infection. Compared to age-matched control mice, the intravenously inoculated C3H/HeJ mice exhibited marked facial edema and marked splenomegaly upon gross examination, while the intradermally inoculated mice developed characteristic eschar-like lesions. The C3H/HeJ mice also exhibited the greatest concentrations of rickettsial DNA from heart, lung, liver, and spleen samples when examined by qPCR. The similarity of the pathology of human disease and sustained infection suggests that the C3H/HeJ strain of mice is a promising candidate for subsequent experiments to examine the tick transmission, dissemination, and pathology ofR. parkeririckettsiosis.

Mitbringsel aus den Ferien

Praxis ◽  
2005 ◽  
Vol 94 (47) ◽  
pp. 1869-1870
Author(s):  
Balestra ◽  
Nüesch
Keyword(s):  
Rocky Mountains ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
Rickettsia Conorii ◽  
Rocky Mountain Spotted Fever ◽  
Klinische Diagnose ◽  
Rickettsia Rickettsii

Eine 37-jährige Patientin stellt sich nach der Rückkehr von einer Rundreise durch Nordamerika mit einem Status febrilis seit zehn Tagen und einem makulösem extremitätenbetontem Exanthem seit einem Tag vor. Bei suggestiver Klinik und Besuch der Rocky Mountains wird ein Rocky Mountain spotted fever diagnostiziert. Die Serologie für Rickettsia conorii, die mit Rickettsia rickettsii kreuzreagiert, war positiv und bestätigte die klinische Diagnose. Allerdings konnte der beweisende vierfache Titeranstieg, möglicherweise wegen spät abgenommener ersten Serologie, nicht nachgewiesen werden. Nach zweiwöchiger antibiotischer Therapie mit Doxycycline waren Status febrilis und Exanthem regredient.

A Case of Japanese Spotted Fever, for which Differential Diagnosis was Required with Severe Fever with Thrombocytopenia Syndrome (SFTS)

2016 ◽  
Vol 78 (2) ◽  
pp. 156-160
Author(s):  
Kanami SAITO ◽  
Toshihiro SATO ◽  
Takashi TAKAGI ◽  
Masanori KAWAGUCHI ◽  
Syogo URABE ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Spotted Fever ◽  
Severe Fever

Minimal Transmission in an Influenza A (H3N2) Human Challenge-Transmission Model with Exposure Events in a Controlled Environment

2019 ◽  
Author(s):  
Jonathan S. Nguyen-Van-Tam ◽  
Ben Killingley ◽  
Joanne Enstone ◽  
Michael Hewitt ◽  
Jovan Pantelic ◽  
...  
Keyword(s):  
Influenza A ◽  
Transmission Model ◽  
Controlled Environment

Mosquito and Tick-borne Illnesses in the United States. Guidelines for the Recognition and Empiric Treatment of Zoonotic Diseases in the Wilderness.

2019 ◽  
Vol 19 (3) ◽  
pp. 238-257
Author(s):  
Suresh Antony
Keyword(s):  
United States ◽  
Lyme Disease ◽  
Spotted Fever ◽  
Disease Process ◽  
Rocky Mountain ◽  
The United States ◽  
Health Care Facilities ◽  
Diagnostic Tools ◽  
Rocky Mountain Spotted Fever ◽  
Number Of Patients

Background:In the United States, tick-borne illnesses account for a significant number of patients that have been seen and treated by health care facilities. This in turn, has resulted in a significant morbidity and mortality and economic costs to the country.Methods:The distribution of these illnesses is geographically variable and is related to the climate as well. Many of these illnesses can be diagnosed and treated successfully, if recognized and started on appropriate antimicrobial therapy early in the disease process. Patient with illnesses such as Lyme disease, Wet Nile illness can result in chronic debilitating diseases if not recognized early and treated.Conclusion:This paper covers illnesses such as Lyme disease, West Nile illness, Rocky Mountain Spotted fever, Ehrlichia, Tularemia, typhus, mosquito borne illnesses such as enteroviruses, arboviruses as well as arthropod and rodent borne virus infections as well. It covers the epidemiology, clinical features and diagnostic tools needed to make the diagnosis and treat these patients as well.

scholarly journals Model-based evaluation of school- and non-school-related measures to control the COVID-19 pandemic

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ganna Rozhnova ◽  
Christiaan H. van Dorp ◽  
Patricia Bruijning-Verhagen ◽  
Martin C. J. Bootsma ◽  
Janneke H. H. M. van de Wijgert ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Additional Benefit ◽  
Transmission Model ◽  
Time Points ◽  
School Based ◽  
Admission Data ◽  
Age Structured ◽  
The Impact ◽  
Pandemic Wave

AbstractThe role of school-based contacts in the epidemiology of SARS-CoV-2 is incompletely understood. We use an age-structured transmission model fitted to age-specific seroprevalence and hospital admission data to assess the effects of school-based measures at different time points during the COVID-19 pandemic in the Netherlands. Our analyses suggest that the impact of measures reducing school-based contacts depends on the remaining opportunities to reduce non-school-based contacts. If opportunities to reduce the effective reproduction number (Re) with non-school-based measures are exhausted or undesired and Re is still close to 1, the additional benefit of school-based measures may be considerable, particularly among older school children. As two examples, we demonstrate that keeping schools closed after the summer holidays in 2020, in the absence of other measures, would not have prevented the second pandemic wave in autumn 2020 but closing schools in November 2020 could have reduced Re below 1, with unchanged non-school-based contacts.

scholarly journals Evolution of disease transmission during the COVID-19 pandemic: patterns and determinants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Zhu ◽  
Blanca Gallego
Keyword(s):  
Public Health ◽  
Disease Transmission ◽  
Clustering Algorithm ◽  
Health Interventions ◽  
Transmission Model ◽  
Model Parameters ◽  
Public Health Interventions ◽  
Forecasting Accuracy ◽  
Time Lagged ◽  
The Impact

AbstractEpidemic models are being used by governments to inform public health strategies to reduce the spread of SARS-CoV-2. They simulate potential scenarios by manipulating model parameters that control processes of disease transmission and recovery. However, the validity of these parameters is challenged by the uncertainty of the impact of public health interventions on disease transmission, and the forecasting accuracy of these models is rarely investigated during an outbreak. We fitted a stochastic transmission model on reported cases, recoveries and deaths associated with SARS-CoV-2 infection across 101 countries. The dynamics of disease transmission was represented in terms of the daily effective reproduction number ($$R_t$$ R t ). The relationship between public health interventions and $$R_t$$ R t was explored, firstly using a hierarchical clustering algorithm on initial $$R_t$$ R t patterns, and secondly computing the time-lagged cross correlation among the daily number of policies implemented, $$R_t$$ R t , and daily incidence counts in subsequent months. The impact of updating $$R_t$$ R t every time a prediction is made on the forecasting accuracy of the model was investigated. We identified 5 groups of countries with distinct transmission patterns during the first 6 months of the pandemic. Early adoption of social distancing measures and a shorter gap between interventions were associated with a reduction on the duration of outbreaks. The lagged correlation analysis revealed that increased policy volume was associated with lower future $$R_t$$ R t (75 days lag), while a lower $$R_t$$ R t was associated with lower future policy volume (102 days lag). Lastly, the outbreak prediction accuracy of the model using dynamically updated $$R_t$$ R t produced an average AUROC of 0.72 (0.708, 0.723) compared to 0.56 (0.555, 0.568) when $$R_t$$ R t was kept constant. Monitoring the evolution of $$R_t$$ R t during an epidemic is an important complementary piece of information to reported daily counts, recoveries and deaths, since it provides an early signal of the efficacy of containment measures. Using updated $$R_t$$ R t values produces significantly better predictions of future outbreaks. Our results found variation in the effect of early public health interventions on the evolution of $$R_t$$ R t over time and across countries, which could not be explained solely by the timing and number of the adopted interventions.

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