Hantavirus infection in rodents and haemorrhagic fever with renal syndrome in Shaanxi province, China, 1984–2012

2014 ◽  
Vol 143 (2) ◽  
pp. 405-411 ◽  
Author(s):  
P. B. YU ◽  
H. Y. TIAN ◽  
C. F. MA ◽  
C. A. MA ◽  
J. WEI ◽  
...  
Keyword(s):  
Prevalence Rate ◽  
Generalized Linear Model ◽  
Disease Surveillance ◽  
Shaanxi Province ◽  
Hantavirus Infection ◽  
Infection Prevalence ◽  
Haemorrhagic Fever ◽  
Disease Epidemics ◽  
The Relationship ◽  
Rodent Abundance

SUMMARYThe transmission of haemorrhagic fever with renal syndrome (HFRS) is deeply influenced by the reservoir and hantavirus prevalence rate. In this study, a surveillance on human HFRS cases, relative rodent abundance, and hantavirus infection prevalence was conducted in Shaanxi province, China, during 1984–2012. A generalized linear model with Poisson-distributed residuals and a log link was used to quantify the relationship between reservoir, virus and HFRS cases. The result indicated that there was a significant association of HFRS incidence with relative rodent density and the prevalence rate. This research provides evidence that the changes of infection prevalence in the reservoir could lead directly to the emergence of a new epidemic. It was concluded that the measurement of a number of these variables could be used in disease surveillance to give useful advance warning of potential disease epidemics.

Environmental variability and the transmission of haemorrhagic fever with renal syndrome in Changsha, People's Republic of China

2012 ◽  
Vol 141 (9) ◽  
pp. 1867-1875 ◽  
Author(s):  
H. XIAO ◽  
L. D. GAO ◽  
X. J. LI ◽  
X. L. LIN ◽  
X. Y. DAI ◽  
...  
Keyword(s):  
Disease Surveillance ◽  
Environmental Variability ◽  
Southern Oscillation ◽  
Host Population ◽  
Haemorrhagic Fever ◽  
Rodent Host ◽  
Transmission Potential ◽  
Republic Of China ◽  
Disease Occurrence ◽  
Disease Epidemics

SUMMARYThe transmission of haemorrhagic fever with renal syndrome (HFRS) is influenced by climatic, reservoir and environmental variables. The epidemiology of the disease was studied over a 6-year period in Changsha. Variables relating to climate, environment, rodent host distribution and disease occurrence were collected monthly and analysed using a time-series adjusted Poisson regression model. It was found that the density of the rodent host and multivariate El Niño Southern Oscillation index had the greatest effect on the transmission of HFRS with lags of 2–6 months. However, a number of climatic and environmental factors played important roles in affecting the density and transmission potential of the rodent host population. It was concluded that the measurement of a number of these variables could be used in disease surveillance to give useful advance warning of potential disease epidemics.

scholarly journals Eight Simple Guidelines for Improved Understanding of Transformations and Nonlinear Effects

2021 ◽  
pp. 109442812199190
Author(s):  
Mikko Rönkkö ◽  
Eero Aalto ◽  
Henni Tenhunen ◽  
Miguel I. Aguirre-Urreta
Keyword(s):  
Generalized Linear Model ◽  
Functional Form ◽  
Nonlinear Models ◽  
Nonlinear Effects ◽  
Recent Past ◽  
Organizational Research ◽  
Common Practices ◽  
Individual Variables ◽  
The Individual ◽  
The Relationship

Transforming variables before analysis or applying a transformation as a part of a generalized linear model are common practices in organizational research. Several methodological articles addressing the topic, either directly or indirectly, have been published in the recent past. In this article, we point out a few misconceptions about transformations and propose a set of eight simple guidelines for addressing them. Our main argument is that transformations should not be chosen based on the nature or distribution of the individual variables but based on the functional form of the relationship between two or more variables that is expected from theory or discovered empirically. Building on a systematic review of six leading management journals, we point to several ways the specification and interpretation of nonlinear models can be improved.

scholarly journals The relationship of arsenic levels in drinking water and the prevalence rate of skin lesions in Bangladesh.

1999 ◽  
Vol 107 (9) ◽  
pp. 727-729 ◽  
Author(s):  
M Tondel ◽  
M Rahman ◽  
A Magnuson ◽  
I A Chowdhury ◽  
M H Faruquee ◽  
...  
Keyword(s):  
Drinking Water ◽  
Prevalence Rate ◽  
Skin Lesions ◽  
Relationship Of ◽  
The Relationship

Increased Income, Energy Choice and Environment Sustainable Development : Based on the Survey in Western Mountainous Areas in China

2011 ◽  
Vol 361-363 ◽  
pp. 1606-1609
Author(s):  
Xiu Jun Tai
Keyword(s):  
Sustainable Development ◽  
Rural Households ◽  
Shaanxi Province ◽  
Western China ◽  
Energy Structure ◽  
Mountainous Areas ◽  
Additional Insight ◽  
The Relationship ◽  
Xi’An City ◽  
Energy Choice

The relationship between increasing income of rural households and energy choice is explored. Previous studies have been equivocal because they ignored the consideration of out-migration, which is a distinctive characteristic of present China . This study provides additional insight by considering income structure and energy structure of rural households in western China. The research was conducted in Zhouzhi County in the jurisdiction of Xi’an city, Shaanxi Province, China. Through questionnaire survey, 1074 rural households’ detailed information about their livelihoods were obtained. After descriptive statistics analysis and econometrics model analysis, we provide evidence that migration income plays a important role when rural households choosing modern energy such as electricity or gas, which shows higher income housholds like to choose cleaner but expensive energy. We also find out-migration can reduce family firewood consumption, transforming the use of firewood to other cleaner forms of energy, which can keep the ecological environment sustainable development.

scholarly journals An outbreak of haemorrhagic fever with renal syndrome linked with mountain recreational activities in Zagreb, Croatia, 2017

2018 ◽  
Vol 146 (10) ◽  
pp. 1236-1239
Author(s):  
Z. Lovrić ◽  
B. Kolarić ◽  
M. L. Kosanović Ličina ◽  
M. Tomljenović ◽  
O. Đaković Rode ◽  
...  
Keyword(s):  
Risk Factors ◽  
Logistic Regression ◽  
Conditional Logistic Regression ◽  
Hantavirus Infection ◽  
Haemorrhagic Fever ◽  
Recreational Activity ◽  
Odds Ratios ◽  
Recreational Activities

AbstractIn 2017 Zagreb faced the largest outbreak of haemorrhagic fever with renal syndrome (HFRS) to date. We investigated to describe the extent of the outbreak and identify risk factors for infection. We compared laboratory-confirmed cases of Hantavirus infection in Zagreb residents with the onset of illness after 1 January 2017, with individually matched controls from the same household or neighbourhood. We calculated adjusted matched odds ratios (amOR) using conditional logistic regression. During 2017, 104 cases were reported: 11–81 years old (median 37) and 71% (73) male. Compared with 104 controls, cases were more likely to report visiting Mount Medvednica (amOR 60, 95% CI 6–597), visiting a forest (amOR 46, 95% CI 4.7–450) and observing rodents (amOR 20, 95% CI 2.6–159). Seventy per cent of cases (73/104) had visited Mount Medvednica prior to infection. Among participants who had visited Mount Medvednica, cases were more likely to have drunk water from a spring (amOR 22, 95% CI 1.9–265), observed rodents (amOR 17, 95% CI 2–144), picked flowers (amOR 15, 95% CI 1.2–182) or cycled (amOR 14, 95% CI 1.6–135). Our study indicated that recreational activity around Mount Medvednica was associated with HFRS. We recommend enhanced surveillance of the recreational areas during an outbreak.

scholarly journals Characteristics of Nontuberculous Mycobacterial Infections at a Midwestern Tertiary Hospital: A Retrospective Study of 365 Patients

2020 ◽  
Vol 7 (6) ◽  
Author(s):  
Claire E Hannah ◽  
Bradley A Ford ◽  
Jina Chung ◽  
Dilek Ince ◽  
Karolyn A Wanat
Keyword(s):  
Risk Factors ◽  
Mycobacterium Avium ◽  
Disease Surveillance ◽  
Mycobacterium Avium Complex ◽  
Retrospective Chart Review ◽  
Common Species ◽  
Tertiary Hospital ◽  
Population Based ◽  
Clinical Findings ◽  
Infection Prevalence

Abstract Background The prevalence of infections due to nontuberculous mycobacteria (NTM) is increasing worldwide, yet little is known about the epidemiology and pathophysiology of these ubiquitous environmental organisms. Pulmonary disease due to Mycobacterium avium complex is most prevalent, but many other NTM species can cause disease in virtually any organ system. As NTM becomes an increasingly common cause of morbidity and mortality, more information is needed about the epidemiology of NTM disease. Methods We conducted a retrospective chart review of all patients with cultures that grew NTM at a Midwestern tertiary hospital from 1996 to 2017. Information on demographics, medical history, clinical findings, treatment, and outcome was obtained from medical records of all NTM isolates. American Thoracic Society/Infectious Diseases Society of America criteria were used to define pulmonary NTM infections. Results We identified 1064 NTM isolates, 365 of which met criteria for NTM infection. Pulmonary cases predominated (185 of 365; 50.7%), followed by skin/soft tissue (56 of 365; 15.3%), disseminated (40 of 365; 11%), and lymphatic (28 of 365; 7.7%) disease. Mycobacterium avium complex was the most common species (184 of 365; 50.4%). Individuals aged >50 years were most affected (207 of 365; 56.7%). Common comorbidities included structural lung disease (116 of 365; 31.8%), use of immunosuppressive medications (78 of 365; 21.4%), malignancy (59 of 365; 16.2%), and human immunodeficiency virus (42 of 365; 11.5%). Conclusions This large cohort provides information on the demographics, risk factors, and disease course of patients with pulmonary and extrapulmonary NTM infections. Most patients had medical comorbidities that resulted in anatomic, genetic, or immunologic risk factors for NTM infection. Further population-based studies and increased disease surveillance are warranted to further characterize NTM infection prevalence and trends.

scholarly journals Variation in Angiostrongylus cantonensis infection in definitive and intermediate hosts in Hawaii, a global hotspot of rat lungworm disease

Parasitology ◽  
2020 ◽  
pp. 1-10
Author(s):  
Chris N. Niebuhr ◽  
Shane R. Siers ◽  
Israel L. Leinbach ◽  
Lisa M. Kaluna ◽  
Susan I. Jarvi
Keyword(s):  
Disease Surveillance ◽  
Strong Predictor ◽  
Management Strategies ◽  
Angiostrongylus Cantonensis ◽  
Infection Prevalence ◽  
Intermediate Hosts ◽  
Related Factors ◽  
Crucial Component ◽  
Wild Host ◽  
Rat Lungworm

Abstract Angiostrongylus cantonensis (rat lungworm) is a tropical and subtropical parasitic nematode, with infections in humans causing angiostrongyliasis (rat lungworm disease), characterized by eosinophilic meningitis. Hawaii has been identified as a global hotspot of infection, with recent reports of high infection rates in humans, as well as rat definitive and snail intermediate hosts. This study investigated variation in A. cantonensis infection, both prevalence and intensity, in wild populations of two species of rats (Rattus exulans and R. rattus) and one species of snail (Parmarion martensi). An overall infection prevalence of 86.2% was observed in P. martensi and 63.8% in rats, with R. exulans (77.4%) greater than R. rattus (47.6%). We found infections to vary with environmental and host-related factors. Body mass was a strong predictor of infection in all three species, with different patterns seen between sexes and species of rats. Infection prevalence and intensity for R. exulans were high in May 2018 and again in February 2019, but generally lower and more variable during the intervening months. Information on sources of variability of infection in wild host populations will be a crucial component in predicting the effectiveness of future disease surveillance or targeted management strategies.

Influence of rodent abundance on nesting success of prairie waterfowl

2008 ◽  
Vol 86 (6) ◽  
pp. 497-506 ◽  
Author(s):  
Rodney W. Brook ◽  
Maria Pasitschniak-Arts ◽  
David W. Howerter ◽  
François Messier
Keyword(s):  
Prairie Pothole Region ◽  
Microtus Pennsylvanicus ◽  
Nesting Success ◽  
Curvilinear Relationship ◽  
Prairie Pothole ◽  
Predator Prey ◽  
Management Plans ◽  
Study Sites ◽  
The Relationship ◽  
Rodent Abundance

Most waterfowl nesting failure in the prairie biome is attributed to predation. However, the contribution of small mammal abundance to the prairie predator–prey cycle and how this affects waterfowl productivity is not known. We modelled seasonal variability of nesting success, including a number of habitat and nest-related variables, to quantify influence of rodent abundance for prairie nesting waterfowl for six study sites in the Prairie Pothole Region of Canada, 1996–1998. We estimated there is a curvilinear relationship between the abundance of meadow voles ( Microtus pennsylvanicus (Ord, 1815)) and the nesting success of ducks. The relationship has characteristics of the alternate prey hypothesis at low vole density and characteristics of the shared prey hypothesis at higher densities. At low vole densities, duck nests appear to be buffered from predation by voles but, at higher densities, nesting success was affected negatively. We recommend that predator–prey dynamics should be included as an integral part of management plans for nesting waterfowl and suggest further research using rigorous experiment design to elucidate mechanisms and pathways responsible for this observed relationship.

scholarly journals Effects of Initial Epidemic Conditions, Sporulation Rate, and Spore Dispersal Gradient on the Spatio-Temporal Dynamics of Plant Disease Epidemics

1998 ◽  
Vol 88 (10) ◽  
pp. 1000-1012 ◽  
Author(s):  
X.-M. Xu ◽  
M. S. Ridout
Keyword(s):  
Spatial Pattern ◽  
Power Law ◽  
Temporal Dynamics ◽  
Initial Conditions ◽  
Disease Incidence ◽  
Disease Status ◽  
Spatio Temporal ◽  
Disease Epidemics ◽  
Sporulation Rate ◽  
The Relationship

A stochastic model that simulates the spread of disease over space and time was developed to study the effects of initial epidemic conditions (number of initial inocula and their spatial pattern), sporulation rate, and spore dispersal gradient on the spatio-temporal dynamics of plant disease epidemics. The spatial spread of disease was simulated using a half-Cauchy distribution with median dispersal distance μ (units of distance). The rate of temporal increase in disease incidence (βI, per day) was influenced jointly by μ and by the sporulation rate λ (spores per lesion per day). The relationship between βI and μ was nonlinear: the increase in βI with increasing μ was greatest when μ was small (i.e., when the dispersal gradient was steep). The rate of temporal increase in disease severity of diseased plants (βS) was affected mainly by λ: βS increased directly with increasing λ. Intraclass correlation (κt), the correlation of disease status of plants within quadrats, increased initially with disease incidence, reached a peak, and then declined as disease incidence approached 1.0. This relationship was well described by a power-law model that is consistent with the binary form of the variance power law. The amplitude of the model relating κt to disease incidence was affected mainly by μ: κt decreased with increasing μ. The shape of the curve was affected mainly by initial conditions, especially the spatial pattern of the initial inocula. Generally, the relationship of spatial autocorrelation (ρt,k), the correlation of disease status of plants at various distances apart, to disease incidence and distance was well described by a four-parameter power-law model. ρt,k increased with disease incidence to a maximum and then declined at higher values of disease incidence, in agreement with a power-law relationship. The amplitude of ρt,k was determined mainly by initial conditions and by μ: ρt,k decreased with increasing μ and was lower for regular patterns of initial inocula. The shape of the ρt,k curve was affected mainly by initial conditions, especially the spatial pattern of the initial inocula. At any level of disease incidence, autocorrelation declined exponentially with spatial lag; the degree of this decline was determined mainly by μ: it was steeper with decreasing μ.

Trypanosoma cruzi Infection Prevalence and Bloodmeal Analysis in Triatomine Vectors of Chagas Disease From Rural Peridomestic Locations in Texas, 2013–2014

2016 ◽  
Vol 53 (4) ◽  
pp. 911-918 ◽  
Author(s):  
Rodion Gorchakov ◽  
Lillian P. Trosclair ◽  
Edward J. Wozniak ◽  
Patricia T. Feria ◽  
Melissa N. Garcia ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Disease Surveillance ◽  
Public Awareness ◽  
Parasite Burden ◽  
Etiologic Agent ◽  
Infection Prevalence ◽  
Transmission Cycle ◽  
High Infection ◽  
History Of

Abstract Protozoan pathogen Trypanosoma cruzi (Chagas, 1909) is the etiologic agent of Chagas disease, which affects millions of people in Latin America. Recently, the disease has been gaining attention in Texas and the southern United States. Transmission cycle of the parasite involves alternating infection between insect vectors and vertebrate hosts (including humans, wildlife, and domestic animals). To evaluate vector T. cruzi parasite burden and feeding patterns, we tested triatomine vectors from 23 central, southern, and northeastern counties of Texas. Out of the 68 submitted specimens, the majority were genetically identified as Triatoma gerstaeckeri (Stal, 1859), with a few samples of Triatoma sanguisuga (LeConte, 1855), Triatoma lecticularia (Stal, 1859), Triatoma rubida (Uhler, 1894), and Triatoma protracta woodi (Usinger, 1939). We found almost two-thirds of the submitted insects were polymerase chain reaction-positive for T. cruzi. Bloodmeal sources were determined for most of the insects, and 16 different species of mammals were identified as hosts. The most prevalent type of bloodmeal was human, with over half of these insects found to be positive for T. cruzi. High infection rate of the triatomine vectors combined with high incidence of feeding on humans highlight the importance of Chagas disease surveillance in Texas. With our previous findings of autochthonous transmission of Chagas disease, urgent measures are needed to increase public awareness, vector control in and around homes, and Chagas screening of residents who present with a history of a triatomine exposure.

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