scholarly journals Risk Factors Associated with Seroprevalence of Chlamydia abortus in Sheep Farms in Ceará, Brazil

2021 ◽  
Vol 49 ◽  
Author(s):  
Ana Milena César Lima ◽  
Francisco Selmo Fernandes Alves ◽  
Raymundo Rizaldo Pinheiro ◽  
Samilly Mesquita Alves ◽  
Daniele Alves De Farias ◽  
...  
Keyword(s):  
Risk Factors ◽  
Disease Transmission ◽  
Safety Information ◽  
Productivity Loss ◽  
The State ◽  
Transmission Risk ◽  
Disease Spread ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chlamydia Abortus ◽  
Seropositive Animal

Background: Chlamydia abortus infections (Chlamydiosis) can cause reproductive problems in sheep, such as abortions and birth defects, leading to farm productivity loss. The symptoms, which are similar to other reproductive diseases, and the microbial pathogenesis make the clinical diagnosis difficult. Chlamydia abortus is a zoonotic pathogen, making it a public health issue because it can infect and induce abortions in humans. This study investigated anti-C. abortus antibody levels and infection risk factors in sheep in the State of Ceará, Brazil.Materials, Methods & Results: Forty-three properties from 10 municipalities in 4 mesoregions in the State of Ceará, Brazil (Sertões, metropolitan Fortaleza, North Ceará and Northwest Ceará) with sheep, goats, cattle, and horses were visited. Five hundred and four serological samples from sheep were collected and tested for anti-C. abortus antibodies using an Enzyme-linked Immunosorbent Assay (ELISA) [IDEXX®, Australia] and all procedures were performed in accordance with the manufacturer's instructions at the Clinical Pathology Laboratory of EMBRAPA Goats and Sheep (Sobral, Brazil). Individual questionnaires were completed about sheep breeding practices and to identify possible C. abortus risks. Seropositive results were found in 18.45 % (93/504 individuals) of sheep, and 88.37 % (38/43 properties) of the herds had at least one seropositive animal. The number of seropositive individuals was significantly different between adults and ewes [P < 0.01; Odds Ratio (OR) = 0.510; 95% confidence interval (CI) = 0.306 - 0.850]. Logistic regression modeling identified a missing health certificate request for newly acquired animals as a chlamydiosis risk factor [P = 0.038; OR = 2.672; 95% CI = 1.058 - 6.749].Discussion: The prevalence of anti-C. abortus antibodies in sheep in the State of Ceara emphasizes the importance of testing and tracking the disease spread among herds; these results were similar to studies in other areas of Brazil. Adult sheep that spend more time on the property may have a higher exposure risk because of increased reproductive activity. Misinformation and technical limitations can influence the proper handling of animals avoiding contagion through the correct use of techniques and recommendations. Disease transmission occurs through the digestive tract and between mother and fetus. Therefore, seropositive (infected) sheep may be related to the breeding system practices, such as allowing contact between sheep and other species on the property (goats, cattle, and horses) during breeding. Acquiring animals from external sources without sufficient health information can increase the transmission risk. Contaminated pastures, water, food, and air also increase transmission risk. The lack of technical and practical knowledge regarding disease prevention and control also contributes to disease transmission, resulting in reproductive losses due to high abortion rates. Chlamydia abortus has zoonotic potential and may infect humans without proper safety information. Therefore, future epidemiological studies are required for a better understanding of the primary risk factors for disease occurrence and spread among herds in the region. Chlamydia abortus infection is present in sheep in Ceará, Brazil. Chlamydiosis information programs should be adopted, sanitary measures implemented, and the epidemiological surveillance of sheep herds strengthened.

scholarly journals Livestock movement informs the risk of disease spread in traditional production systems in East Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Divine Ekwem ◽  
Thomas A. Morrison ◽  
Richard Reeve ◽  
Jessica Enright ◽  
Joram Buza ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Production Systems ◽  
Control Strategies ◽  
Herd Size ◽  
Transmission Risk ◽  
Disease Spread ◽  
Transmission Potential ◽  
Spatial And Temporal Scales ◽  
Transmission Distance ◽  
Risk Of Disease

AbstractIn Africa, livestock are important to local and national economies, but their productivity is constrained by infectious diseases. Comprehensive information on livestock movements and contacts is required to devise appropriate disease control strategies; yet, understanding contact risk in systems where herds mix extensively, and where different pathogens can be transmitted at different spatial and temporal scales, remains a major challenge. We deployed Global Positioning System collars on cattle in 52 herds in a traditional agropastoral system in western Serengeti, Tanzania, to understand fine-scale movements and between-herd contacts, and to identify locations of greatest interaction between herds. We examined contact across spatiotemporal scales relevant to different disease transmission scenarios. Daily cattle movements increased with herd size and rainfall. Generally, contact between herds was greatest away from households, during periods with low rainfall and in locations close to dipping points. We demonstrate how movements and contacts affect the risk of disease spread. For example, transmission risk is relatively sensitive to the survival time of different pathogens in the environment, and less sensitive to transmission distance, at least over the range of the spatiotemporal definitions of contacts that we explored. We identify times and locations of greatest disease transmission potential and that could be targeted through tailored control strategies.

Mapping the Potential for Infectious Disease Transmission in a Wide-Body Aircraft Cabin

2019 ◽  
Author(s):  
Seif Mahmoud ◽  
James S. Bennett ◽  
Mohammad H. Hosni ◽  
Byron Jones
Keyword(s):  
Infectious Diseases ◽  
Disease Transmission ◽  
Radial Distance ◽  
Transmission Risk ◽  
Disease Spread ◽  
Health Concern ◽  
Tracer Gas ◽  
Infectious Disease Transmission ◽  
Gas Concentration ◽  
Aircraft Cabin

Abstract With more than two billion passengers annually, in-flight transmission of infectious diseases is a major global health concern. It is widely believed that principal transmission risk associated with air travel for most respiratory infectious diseases is limited to within two rows of an infectious passenger. However, several passengers became infected despite sitting several rows away from the contagious passenger. This work thoroughly investigated the potential for disease spread inside airplane cabins using tracer gas to quantify airborne dispersion. Measurements were conducted in a full-scale, 11-row mock-up of a wide-body aircraft cabin. Heated mannequins to simulate passengers’ thermal load were placed on the cabin seats. Tracer gas was injected at the breathing level at four different hypothetical contagious passenger locations. The tracer gas concentration was measured radially up to 3.35 m away from the injection location representing four rows of a standard aircraft. A four-port sampling tree was used to collect samples at the breathing level at four different radial locations simultaneously. Each port was sampled for 30 minutes. A total of 42 tests were conducted in matching pairs to alleviate potential statistical or measurements bias. The results showed that the airflow pattern inside the mock-up airplane cabin plays a major role in determining tracer gas concentration meaning that the concentration at the same radial distance in different directions are not necessarily the same. Also, due to the air distribution pattern and cabin walls, concentrations at some seats may be higher than the source seat.

scholarly journals Assessment of Airborne Disease Transmission Risk and Energy Impact of HVAC Mitigation Strategies

2021 ◽  
Author(s):  
Michael J. Risbeck ◽  
Martin Z. Bazant ◽  
Zhanhong Jiang ◽  
Young M. Lee ◽  
Kirk H. Drees ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Significant Risk ◽  
Mitigation Strategies ◽  
Transmission Risk ◽  
Disease Spread ◽  
Particle Removal ◽  
Outdoor Air ◽  
Common Basis ◽  
Air Ventilation ◽  
Airborne Disease

The COVID-19 pandemic has focused renewed attention on the ways in which building HVAC systems may be operated to mitigate the risk of airborne disease transmission. The most common suggestion is to increase outdoor-air ventilation rates so as to dilute the concentrations of infectious aerosol particles indoors. Although this strategy does reduce the likelihood of disease spread, it is often much more costly than other strategies that provide equivalent particle removal or deactivation. To address this tradeoff and arrive at practical recommendations, we explain how different mitigation strategies can be expressed in terms of equivalent outdoor air (EOA) to provide a common basis for energy analysis. We then show the effects of each strategy on EOA delivery and energy cost in simulations of realistic buildings in a variety of climates. Key findings are that in-duct filtration is often the most efficient mitigation strategy, while significant risk reduction generally requires increasing total airflow to the system, either through adjusted HVAC setpoints or standalone disinfection devices.

scholarly journals Prevalence and risk factors for Toxoplasma gondii in sheep in the State of Paraíba, Northeastern Brazil

2015 ◽  
Vol 24 (3) ◽  
pp. 383-386 ◽  
Author(s):  
Érico Luís de Barros Correia ◽  
Thais Ferreira Feitosa ◽  
Fabrine Alexandre dos Santos ◽  
Sérgio Santos de Azevedo ◽  
Hilda Fátima de Jesus Pena ◽  
...  
Keyword(s):  
Risk Factors ◽  
Toxoplasma Gondii ◽  
Odds Ratio ◽  
Antibody Test ◽  
The State ◽  
Northeastern Brazil ◽  
Flock Size ◽  
Seropositive Animal ◽  
Indirect Immunofluorescent ◽  
Immunofluorescent Antibody Test

The aims of this survey were to determine the flock-level and animal-level prevalences of anti-Toxoplasma gondii antibodies in sheep in the State of Paraíba, Northeastern Brazil, and to identify risk factors. Blood samples were collected from 540 sheep in 63 flocks in 14 municipalities in the Sertão mesoregion. To serologically diagnose T. gondiiinfection, the indirect immunofluorescent antibody test (IFAT) was used. Flocks with at least one seropositive animal were considered positive. Among the 63 flocks, 28 (44.44%) were positive, and 60 (11.11%) of the 540 animals were seropositive. Variable flock size > 25 animals was identified as a risk factor (odds ratio = 3.2; 95% CI = 1.09 – 9.34; P = 0.033). The results from this survey demonstrate that T. gondii is spread among sheep in the State of Paraíba.

scholarly journals Epidemiological analysis of Toxoplasma gondii infection in sheep in the state of Pernambuco, Brazil

2017 ◽  
Vol 38 (5) ◽  
pp. 3059 ◽  
Author(s):  
Érica Chaves Lúcio ◽  
Juliana De Lima Pimentel ◽  
Saruanna Millena Dos Santos Clemente ◽  
Luenda Menezes Novaes Sá ◽  
Júnior Mário Baltazar Oliveira ◽  
...  
Keyword(s):  
Risk Factors ◽  
Toxoplasma Gondii ◽  
Preventive Measures ◽  
Fluorescent Antibody ◽  
Antibody Test ◽  
The State ◽  
Epidemiological Analysis ◽  
Seropositive Animal ◽  
Questionnaire Form ◽  
Toxoplasma Gondii Infection

The objective of this study was to determine the seroprevalence of anti-Toxoplasma gondii antibodies in sheep from the Agreste and Sertão regions of Pernambuco in Brazil and to analyze the risk factors associated with T. gondii infection. A total of 250 sheep from 14 sheep farms across the state of Pernambuco were used as samples. Indirect Fluorescent Antibody Test (IFAT) was used for the detection of anti-T. gondii antibodies, adopting a cut-off dilution of 1:64. In order to determine risk factors, farm owners were subjected to a questionnaire form enquiring about the aspects of operational hygiene and sanitary systems. Thirty-four of the 250 samples (13.60%, 95% CI= 9.61% - 18.48%) in the study were determined to be positive, and 10 out of 14 (71.42%) of the sheep farms showed at least one seropositive animal. Titers for the 34 positive samples presented 8 samples at 64 (23.53%), 3 at 128 (8.82%), 3 at 256 (8.82%), 13 at 512 (38.23%), and 7 at 1024 (20.60%). After regression logistics, only the supply of silage (p= 0.009; OR=2.79, CI 95%= 1.29 - 6.0) was confirmed as a risk factor. The study was able to conclude that infection with T. gondii was prevalent in the sampled sheep farms in the state of Pernambuco, and that it was imperative to adopt preventive measures in order to effectively curb the identified risk factors.

scholarly journals Methods to infer transmission risk factors in complex outbreak data

2011 ◽  
Vol 9 (68) ◽  
pp. 456-469 ◽  
Author(s):  
Simon Cauchemez ◽  
Neil M. Ferguson
Keyword(s):  
Risk Factors ◽  
Missing Data ◽  
Disease Transmission ◽  
Control Strategies ◽  
Model Fitting ◽  
Structured Populations ◽  
Transmission Risk ◽  
Effective Control ◽  
Reconstruction Methods ◽  
History Of

Data collected during outbreaks are essential to better understand infectious disease transmission and design effective control strategies. But analysis of such data is challenging owing to the dependency between observations that is typically observed in an outbreak and to missing data. In this paper, we discuss strategies to tackle some of the ongoing challenges in the analysis of outbreak data. We present a relatively generic statistical model for the estimation of transmission risk factors, and discuss algorithms to estimate its parameters for different levels of missing data. We look at the problem of computational times for relatively large datasets and show how they can be reduced by appropriate use of discretization, sufficient statistics and some simple assumptions on the natural history of the disease. We also discuss approaches to integrate parametric model fitting and tree reconstruction methods in coherent statistical analyses. The methods are tested on both real and simulated datasets of large outbreaks in structured populations.

scholarly journals 205Zoonotic disease transmission risk in displaced populations

2021 ◽  
Vol 50 (Supplement_1) ◽  
Author(s):  
Gates Scholar Dorien Braam ◽  
Freya Jephcott ◽  
James Wood
Keyword(s):  
Risk Factors ◽  
Disease Transmission ◽  
Disease Risk ◽  
Forced Migration ◽  
Zoonotic Disease ◽  
Humanitarian Assistance ◽  
Transmission Risk ◽  
Case Study Methodology ◽  
Displaced Populations ◽  
Zoonotic Disease Transmission

Abstract Background Repeated spillover events of zoonotic diseases from animals to humans, in combination with unprecedented levels of forced migration, present a major challenge to the global health security agenda. Infectious disease risk is affected by a range of ecological, political and socio-economic drivers. Methods This study uses a qualitative case study methodology to determine how displacement affects the risks of zoonotic disease transmission. Based on key informant interviews and observational studies in Jordan and Pakistan, the study analyses social-structural factors impacting zoonotic disease transmission. Results The study shows that displacement may influence zoonotic disease transmission through its impact on environmental, socio-economic and behavioural factors, influenced by historical, political and socio-economic processes. Sporadic outbreaks of zoonoses including cutaneous leishmaniasis, rabies and Tuberculosis are reported among displaced populations. Risk factors include a decline in health services, increased population density, changes in environment, and reduced quality and availability of shelter, water and nutrition, in turn determining vulnerability to vectors and pathogens. Conclusions Risk factors affecting zoonoses in displacement are complex and interlinked. While the presence of animals may increase the risk in densely populated areas lacking hygiene, livestock may be beneficial to the health status of displaced by improving nutrition. Responses need to be interdisciplinary, multilevel and contextualized. Key messages To mitigate the risk of zoonotic disease transmission during displacement, responses need to include pathogen and vector control, as well as reducing vulnerability to disease, including through access to health and veterinary services and humanitarian assistance.

scholarly journals Soroepidemiological survey of chlamydia abortus infection in bovine in the State of Pernambuco, Brazil

2021 ◽  
Vol 42 (1) ◽  
pp. 229-240
Author(s):  
Adalberto Leite da Silva Neto ◽  
◽  
Bruno Pajeú e Silva ◽  
Érica Chaves Lúcio ◽  
Sérgio Alves do Nascimento ◽  
...  
Keyword(s):  
Risk Factors ◽  
Dairy Cattle ◽  
The State ◽  
Serum Samples ◽  
Chlamydia Abortus ◽  
Management Measures ◽  
Cattle Herds ◽  
Commercial Enzyme Immunoassay ◽  
First Time ◽  
Intensive System

The objective of this study was to conduct a seroepidemiological survey of Chlamydia abortus infection in dairy cattle herds. A total of 303 blood serum samples were collected from 24 property in Vale do Ipanema microregion in the state of Pernambuco, Brazil. For the diagnosis of C. abortus infection, a commercial enzyme immunoassay kit (ELISA) was used. A prevalence of 34.0% (103/303; 95% CI: 28.7%-39.7%) of infected animals was identified. In 79.8% (19/24) of the properties, at least one infected animal was detected. The risk factors identified were: semi-intensive system (OR = 3.47, p ≤ 0.000), extensive system (OR = 8.14; p ≤ 0.000), supply of water in troughs and directly at the fountain (OR = 2.29, p = 0.002), pasture rent (OR = 1.72, p = 0.041), use of artificial insemination (AI) (OR = 3.07, p = 0.002), and use of AI associated with natural mount (OR = 2.22, p = 0.003). The occurrence of C. abortus infection in dairy cattle in the state of Pernambuco, Brazil, was recorded for the first time. It is concluded that the infection by this agent is present in the analyzed herds and that hygienic and sanitary management measures based on the identified risk factors should be implemented to avoid reproductive losses and losses to the producers.

scholarly journals Seroprevalence and Risk Factors Associated with Brucella Infection in Camels in the Puntland State of Somalia

2021 ◽  
Vol 8 (7) ◽  
pp. 137
Author(s):  
Ahmed Said Mohamud ◽  
John Pilate Kothowa ◽  
Ruth Lindizyani Mfune ◽  
Melai Mubanga ◽  
Jacques Godfroid ◽  
...  
Keyword(s):  
Risk Factors ◽  
Small Ruminants ◽  
Epidemiological Data ◽  
Antibody Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Consumption ◽  
Binary Logistic Regression Model ◽  
Serological Tests ◽  
Cross Sectional ◽  
Seropositive Animal

Brucellosis is an important zoonotic disease caused by members of the genus Brucella. Camel brucellosis has been reported in almost all camel-rearing countries in Africa and Asia. A cross-sectional study was conducted between February 2020 and February 2021 in Galkayo, Garowe, and Bosaso districts in the Puntland State of Somalia to investigate the seroprevalence and risk factors of brucellosis in camels. A competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect anti-Brucella antibodies, while a structured questionnaire was used to collect epidemiological data. A total of 441 camel sera were screened against Brucella antibodies. Thirty-one (7%; 95% CI: 4.8–9.8%) samples were positive, and thirteen (54.2%; 95% CI: 32.8–74.4%) out of the twenty-four farms sampled had at least one seropositive animal. Galkayo district had the highest number of Brucella-seropositive camels (10.3%), followed by Bosaso district (8.6%), while Garowe district had the lowest number of seropositive camels (1.4%). The binary logistic regression model revealed that camels in Galkayo district (p = 0.015; OR: 9.428; 95% CI: 1.539–57.755), camels from large herd sizes of >50 animals (p = 0.019; OR: 5.822; 95% CI: 1.336–25.371), and those in contact with small ruminants (p = 0.011; OR: 10.941; 95% CI: 1.728–69.285) were significantly associated with seropositive cases of camel brucellosis in the Puntland State of Somalia. The present study shows that Brucella infections in camels are prevalent in the three districts covered by the study. This poses a public health risk, because milk from these camels is used for human consumption. Studies focusing on the isolation of Brucella strains in camels and investigating brucellosis in ruminants and humans are recommended in the study area. Validation of serological tests—including c-ELISA—for Brucella antibody detection in camels is also needed.

scholarly journals Modeling and Multiobjective Optimization of Indoor Airborne Disease Transmission Risk and Associated Energy Consumption for Building HVAC Systems

2021 ◽  
Author(s):  
Michael James Risbeck ◽  
Martin Z. Bazant ◽  
Zhanhong Jiang ◽  
Young M Lee ◽  
Kirk H Drees ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Disease Transmission ◽  
Weather Conditions ◽  
Infection Risk ◽  
Hvac Systems ◽  
Transmission Risk ◽  
Disease Spread ◽  
Risk Levels ◽  
Occupant Comfort ◽  
Airborne Disease

The COVID-19 pandemic has renewed interest in assessing how the operation of HVAC systems influences the risk of airborne disease transmission in buildings. Various processes, such as ventilation and filtration, have been shown to reduce the probability of disease spread by removing or deactivating exhaled aerosols that potentially contain infectious material. However, such qualitative recommendations fail to specify how much of these or other disinfection techniques are needed to achieve acceptable risk levels in a particular space. An additional complication is that application of these techniques inevitably increases energy costs, the magnitude of which can vary significantly based on local weather. Moreover, the operational flexibility available to the HVAC system may be inherently limited by equipment capacities and occupant comfort requirements. Given this knowledge gap, we propose a set of dynamical models that can be used to estimate airborne transmission risk and energy consumption for building HVAC systems, based on comfort preferences and weather conditions. By combining physics-based material balances with phenomenological models of the HVAC control system, it is possible to predict time-varying airflows and other HVAC variables, which are then used to calculate the key metrics. Through a variety of examples involving real and simulated commercial buildings, we show that our models can be used for monitoring purposes by applying them directly to transient building data as operated, or they may be embedded within a multi-objective optimization framework to evaluate the tradeoff between infection risk and energy consumption. By combining these applications, building managers can determine which spaces are in need of infection risk reduction and how to provide that reduction at the lowest energy cost. The key finding is that both the baseline infection risk and the most energy-efficient disinfection source can vary significantly from space to space and depend sensitively on the weather, thus underscoring the importance of the quantitative predictions provided by the models.

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