2. Transmission at different scales

Author(s):  
Marta L. Wayne ◽  
Benjamin M. Bolker

The term ‘transmission’ defines infectious disease. Respiratory viruses such as influenza are airborne; diseases such as HIV and hepatitis are transmitted through direct, usually sexual, exchange of bodily fluids; water-borne diseases such as cholera can survive in the environment; and vector-borne pathogens have evolved to use other organisms, especially blood-sucking insects and mites, to travel from one host to another. ‘Transmission at different scales’ considers the filters for encounter and compatibility, mathematical modelling of epidemic dynamics, and the key factors of virulence, resistance, and tolerance.

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1164
Author(s):  
Weiwei Ling ◽  
Pinxia Wu ◽  
Xiumei Li ◽  
Liangjin Xie

By using differential equations with discontinuous right-hand sides, a dynamic model for vector-borne infectious disease under the discontinuous removal of infected trees was established after understanding the transmission mechanism of Huanglongbing (HLB) disease in citrus trees. Through calculation, the basic reproductive number of the model can be attained and the properties of the model are discussed. On this basis, the existence and global stability of the calculated equilibria are verified. Moreover, it was found that different I0 in the control strategy cannot change the dynamic properties of HLB disease. However, the lower the value of I0, the fewer HLB-infected citrus trees, which provides a theoretical basis for controlling HLB disease and reducing expenditure.


2012 ◽  
Vol 54 (1-2) ◽  
pp. 23-36 ◽  
Author(s):  
E. K. WATERS ◽  
H. S. SIDHU ◽  
G. N. MERCER

AbstractPatchy or divided populations can be important to infectious disease transmission. We first show that Lloyd’s mean crowding index, an index of patchiness from ecology, appears as a term in simple deterministic epidemic models of the SIR type. Using these models, we demonstrate that the rate of movement between patches is crucial for epidemic dynamics. In particular, there is a relationship between epidemic final size and epidemic duration in patchy habitats: controlling inter-patch movement will reduce epidemic duration, but also final size. This suggests that a strategy of quarantining infected areas during the initial phases of a virulent epidemic might reduce epidemic duration, but leave the population vulnerable to future epidemics by inhibiting the development of herd immunity.


2018 ◽  
Vol 69 (7) ◽  
pp. 1192-1197 ◽  
Author(s):  
Maddalena Peghin ◽  
Ibai Los-Arcos ◽  
Hans H Hirsch ◽  
Gemma Codina ◽  
Víctor Monforte ◽  
...  

Abstract Background The relationship between community-acquired respiratory viruses (CARVs) and chronic lung allograft dysfunction (CLAD) in lung transplant recipients is still controversial. Methods We performed a prospective cohort study (2009–2014) in all consecutive adult patients (≥18 years) undergoing lung transplantation in the Hospital Universitari Vall d’Hebron (Barcelona, Spain). We systematically collected nasopharyngeal swabs from asymptomatic patients during seasonal changes, from patients with upper respiratory tract infectious disease, lower respiratory tract infectious disease (LRTID), or acute rejection. Nasopharyngeal swabs were analyzed by multiplex polymerase chain reaction. Primary outcome was to evaluate the potential association of CARVs and development of CLAD. Time-dependent Cox regression models were performed to identify the independent risk factors for CLAD. Results Overall, 98 patients (67 bilateral lung transplant recipients; 63.3% male; mean age, 49.9 years) were included. Mean postoperative follow-up was 3.4 years (interquartile range [IQR], 2.5–4.0 years). Thirty-eight lung transplant recipients (38.8%) developed CLAD, in a median time of 20.4 months (IQR, 12–30.4 months). In time-controlled multivariate analysis, CARV-LRTID (hazard ratio [HR], 3.00 [95% confidence interval {CI}, 1.52–5.91]; P = .002), acute rejection (HR, 2.97 [95% CI, 1.51–5.83]; P = .002), and cytomegalovirus pneumonitis (HR, 3.76 [95% CI, 1.23–11.49]; P = .02) were independent risk factors associated with developing CLAD. Conclusions Lung transplant recipients with CARVs in the lower respiratory tract are at increased risk to develop CLAD.


2019 ◽  
Vol 23 (3) ◽  
pp. 328-334
Author(s):  
E. Ya. Yanchevskaya ◽  
O. A. Mesnyankina

Mathematical modeling of diseases is an urgent problem in the modern world. More and more researchers are turning to mathematical models to predict a particular disease, as they help the most correct and accurate study of changes in certain processes occurring in society. Mathematical modeling is indispensable in certain areas of medicine, where real experiments are impossible or difficult, for example, in epidemiology. The article is devoted to the historical aspects of studying the possibilities of mathematical modeling in medicine. The review demonstrates the main stages of development, achievements and prospects of this direction.


2013 ◽  
Vol 7 (9) ◽  
pp. 415
Author(s):  
Kasnodihardjo Kasnodihardjo ◽  
Elsa Elsi

Pada tahun 2009, dilakukan penelitian deskriptif di Kecamatan Jatibarang dan Kecamatan Kedokan Bunder untuk mengetahui faktor-faktor sanitasi lingkungan, dan perilaku ibu-ibu dan kejadian penyakit infeksi pada bayi dan anak. Data dikumpulkan menggunakan kuesioner dengan responden ibu rumah tangga yang mempunyai bayi/ anak balita berjumlah 401 orang. Penyakit diare pada bayi/anak disebabkan oleh media tercemar yang masuk ke sistem pencernaan melalui sumber air untuk minum maupun mandi, cuci, kakus (MCK) yang bukan berasal dari ledeng, keluarga yang tidak mempunyai jamban, ibu yang masih jarang mencuci tangan setelah membersihkan kotoran bayi ataupun setelah buang air besar, meminum dan memakan makanan yang tidak dimasak, dan sampah yang dibuang ke lingkungan. Penyakit Infeksi saluran pernapasan atas (ISPA), pneumonia, dan tuberkulosis paru pada bayi/anak kemungkinan disebabkan media tercemar masuk ke sistem pernapasan melalui sampah yang dibakar, membawa (menggendong) anak sewaktu memasak, merokok di dalam rumah berdekatan dengan bayi/anak, menggunakan obat nyamuk bakar, penderita tuberkulosis paru meludah dan membuang dahak di sembarang tempat dan penderita tidur bersama anggota keluarga yang lain. Penyakit tular vektor pada bayi/anak (malaria) kemungkinan disebabkan upaya pen-cegahan gigitan nyamuk dengan repellent kurang efektif dan penggunaan kelambu masih rendah.In 2009 a descriptive study conducted in the subdistrict Jatibarang and Kedokan Bunder to determine the factors of environmental sanitation, infectious disease in baby/child, and mother’s behavior. Data were collect-ed using questionnaires which respondents are 401 housewives who have a baby/child. Occurrence of diarrhea disease in baby/child because of the possibility of contaminated media through the digestive system by water for drinking and toilets which do not originate from the piping network, families who do not have own toilet, mothers who still seldom washing hands after cleaning the baby’s stool or after a bowel movement, drinking and eating food that is not cooked and throw trash to the environment. Occurrence of respiratory diseases, pneumonia and pulmonary tuberculosis in baby/child possibly because the media is polluted through the respiratory system by burning garbage, carrying baby/children while, smoking at home or adjacent with babies/children, the use of mosquito coils, pulmonary tuberkulosis patients spit and throw phlegm in random places and sleeping with other family members. The occurrence of vector borne diseases in baby/child (malaria) because of the possibility of preventing mosquito bites with repellent less effective, the use of mosquito nets still low.


2021 ◽  
Vol 42 (1) ◽  
pp. 41-48
Author(s):  
A.O. Omonona ◽  
S.A. Abioye ◽  
P.O. Odeniran ◽  
I.O. Ademola

Dipteran flies play significant role in disease transmission to human, domestic and wild animals. The distribution and diversity of dipteran flies of medical and veterinary importance in Old Oyo national park and its significant importance were assessed in relation to altitude and ecology. Twelve Nzi traps were set at 50 m equidistance to capture dipteran flies between February and August 2019. A total of 1529 dipteran flies belonging to five families were captured. More dipteran flies (64.9%) were trapped during the dry season than wet season (35.1%) (X2 = 270.8; P < 0.0001; OR = 3.41). Of the total flies caught, 289 representing 18.9% were identified as haematophagus flies. Differences in the total haematophagus fly 2 abundance was not significant across the altitudinal levels (X2 = 0.432; P = 0.511; OR = 1.13). The relative apparent density (RAD) of 0.47, 0.22, 0.13, 0.09, 0.07 and 0.03 (flies/trap/day) was observed in Glossina, Hippobosca, Tabanus, Haematopota, Chrysops, Ancala and, respectively. The diversity index of 0.55 and 0.76 were determined for Glossina spp. and Tabanids respectively. The non-blood sucking flies in order of abundance are Musca domestica (43.6%), Fanniacanicularis (41.9%), Chrysomyia bezziana (8.9%), Lucilia sericata (5.6%). If the value-chain of ecotourism is to be promoted in the park, vector-borne arthropods need to be controlled through the use of integrated methods. Keywords: Ecological survey, haematophagus flies, Old Oyo national Park, RAD


2020 ◽  
Vol 5 ◽  
pp. 409-441 ◽  
Author(s):  
Christopher E. Overton ◽  
Helena B. Stage ◽  
Shazaad Ahmad ◽  
Jacob Curran-Sebastian ◽  
Paul Dark ◽  
...  

2007 ◽  
Vol 17 (Supplement_I) ◽  
pp. S48-S55 ◽  
Author(s):  
Shuji Hashimoto ◽  
Miyuki Kawado ◽  
Yoshitaka Murakami ◽  
Michiko Izumida ◽  
Akiko Ohta ◽  
...  

2011 ◽  
Vol 2011 ◽  
pp. 1-28 ◽  
Author(s):  
Leon Danon ◽  
Ashley P. Ford ◽  
Thomas House ◽  
Chris P. Jewell ◽  
Matt J. Keeling ◽  
...  

The science of networks has revolutionised research into the dynamics of interacting elements. It could be argued that epidemiology in particular has embraced the potential of network theory more than any other discipline. Here we review the growing body of research concerning the spread of infectious diseases on networks, focusing on the interplay between network theory and epidemiology. The review is split into four main sections, which examine: the types of network relevant to epidemiology; the multitude of ways these networks can be characterised; the statistical methods that can be applied to infer the epidemiological parameters on a realised network; and finally simulation and analytical methods to determine epidemic dynamics on a given network. Given the breadth of areas covered and the ever-expanding number of publications, a comprehensive review of all work is impossible. Instead, we provide a personalised overview into the areas of network epidemiology that have seen the greatest progress in recent years or have the greatest potential to provide novel insights. As such, considerable importance is placed on analytical approaches and statistical methods which are both rapidly expanding fields. Throughout this review we restrict our attention to epidemiological issues.


Author(s):  
Kyu-Myoung Lee ◽  
Kyujin Jung

Following the 2003 the severe acute respiratory syndrome (SARS) and the 2015 Middle East Respiratory Syndrome (MERS) outbreak in South Korea, this research aims to explore and examine the factors influencing the response to infectious diseases, which encompasses both communicable and non-communicable diseases. Through a qualitative research method, this research categorizes the factors as inputs, processes and outputs and applies them into the 2003 SARS and MERS outbreak in South Korea. As the results conducted meta-analyses to comprehensively analyze the correlations of factors influencing disaster response from a Korean context, the findings show that the legislative factor had direct and indirect influence on the overall process of infectious disease response and that Leadership of the central government, establishment of an intergovernmental response system, the need for communication, information sharing and disclosure and onsite response were identified as key factors influencing effective infectious disease response.


Sign in / Sign up

Export Citation Format

Share Document