Investigation of dissemination of aspergillosis in poultry and possible control measures

Fungi belonging to genus Aspegillus are ubiquitous saprophytic microorganisms which are, in certain circumstances, responsible for clinical infections of respiratory tract in all poultry, particularly in young birds. In case of a lung form, Aspergillus fumigatus, A. niger and A. glaucus are the most frequently isolated fungi. In general, poultry is constantly exposed to these fungi in its environment. Predisposing factors, such as long exposition and highly contaminated environment and litter, high humidity in poultry houses, poor ventilation, malnutrition and stress, all contribute to clinical aspergillosis. Some geographic and seasonal regularities are observed in relation to the distribution of disease outbreaks. In this sense, cases of aspergillosis in our country were more frequently noted in wild areas located northern from the rivers Sava and Danube. Influence of some factors on the outbreak and spreading, as well as predominant clinical features of aspergillosis in poultry were investigated in this paper. Possible prophylactic and intervention measures were discussed. The occurrence of Aspergillus sp. in poultry was analyzed according to the clinical and laboratory investigations performed during the two selected years, 2000 and 2010. Widespread aspergillosis was noted in poultry flocks of different age, both in young and adult birds. During the years 2000 and 2010, acute aspergillosis was found in 12 and 16 commercial flocks of chickens and turkeys, respectively. Ocular infection with Aspergillus was determined in 10 day old broilers from two flocks. Aspergillus sp. was isolated from unhatched eggs (6.86%), litter (23.07%), environmental (36.17%) and hatchery swabs (3.85%). Besides the appropriate antifungal therapy, enforcement of proper sanitary-hygiene measures on poultry farms and hatcheries, as well as microbiological control of feed are considered essential for an efficient control of infection and its spreading.

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A stochastic metapopulation state-space approach to modeling and estimating COVID-19 spread

Mathematical Biosciences and Engineering ◽

10.3934/mbe.2021381 ◽

2021 ◽

Vol 18 (6) ◽

pp. 7685-7710

Author(s):

Yukun Tan ◽

◽

Durward Cator III ◽

Martial Ndeffo-Mbah ◽

Ulisses Braga-Neto ◽

...

Keyword(s):

State Space ◽

State Space Model ◽

Synthetic Data ◽

Public Health Intervention ◽

Disease Outbreaks ◽

Real Data ◽

Epidemiological Data ◽

Transmission Parameters ◽

Intervention Measures ◽

Spatio Temporal

<abstract><p>Mathematical models are widely recognized as an important tool for analyzing and understanding the dynamics of infectious disease outbreaks, predict their future trends, and evaluate public health intervention measures for disease control and elimination. We propose a novel stochastic metapopulation state-space model for COVID-19 transmission, which is based on a discrete-time spatio-temporal susceptible, exposed, infected, recovered, and deceased (SEIRD) model. The proposed framework allows the hidden SEIRD states and unknown transmission parameters to be estimated from noisy, incomplete time series of reported epidemiological data, by application of unscented Kalman filtering (UKF), maximum-likelihood adaptive filtering, and metaheuristic optimization. Experiments using both synthetic data and real data from the Fall 2020 COVID-19 wave in the state of Texas demonstrate the effectiveness of the proposed model.</p></abstract>

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The Effect of Social Distancing and Personal Protective Equipment on the Outbreak of SARS-COVID-2: An Agent-Based Modeling Approach

10.21203/rs.3.rs-616489/v1 ◽

2021 ◽

Author(s):

Sohrab Effati ◽

Eman Tavakoli

Keyword(s):

Personal Protective Equipment ◽

Disease Outbreaks ◽

Agent Based Modeling ◽

Control Measures ◽

Protective Equipment ◽

Human Society ◽

Agent Based ◽

Social Distancing ◽

Contagious Diseases ◽

Biological Phenomena

Abstract Biological phenomena such as disease outbreaks can be modeled as a subset of natural phenomena. Coronaviruses, first identified in the 1960s, are contagious diseases being constantly in the area of research and modeling in human society. The latest version of this group, SARS-COVID-2, has caused the Coronavirus disease one of the greatest pandemics in recent years. Due to the nature of this disease, being aware of the ways of transmission and how to prevent it, including social distancing and the use of personal protective equipment (PPE) to improve the general condition of society is of particular importance. In this study, dynamic systems (Susceptible, Exposed, Infected, Asymptomatic, and Recovered individuals as SEIAR), control systems, and Agent-based modeling (ABM) were used to forecast the behavior of the SARS-COVID-2 virus in the community. The numerical results display the undeniable impact of adhering to hygiene protocols. A significant decline in the number of people with the Coronavirus disease, after applying the control measures, indicates their remarkable impact on reducing the disease peak. Moreover, the result of the Agent-based simulation, which is in four ideal cases, show a significant reduction in the number of death as well.

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Seroprevalences of Newly Discovered Porcine Pestiviruses in German Pig Farms

Veterinary Sciences ◽

10.3390/vetsci6040086 ◽

2019 ◽

Vol 6 (4) ◽

pp. 86 ◽

Cited By ~ 3

Author(s):

Michelitsch ◽

Dalmann ◽

Wernike ◽

Reimann ◽

Beer

Keyword(s):

New Species ◽

Disease Outbreaks ◽

State Level ◽

Test System ◽

Control Measures ◽

Federal States ◽

Diarrhea Virus ◽

German Federal States ◽

Pig Farms ◽

Chimeric Construct

Several novel porcine pestiviruses that are linked to disease outbreaks in commercial pig farms were discovered during recent years. Bungowannah pestivirus (BuPV; new species Pestivirus F) causes sudden death in young pigs, but has only ever been isolated in the Australian region Bungowannah. Atypical porcine pestivirus (APPV; new species Pestivirus K) on the other hand has been found in multiple countries worldwide and is potentially linked to congenital tremor, a disease that causes considerable production problems in pig farms. To assess the seroprevalences of both viruses in German commercial farms during the years 2009/10 and 2018, two approaches were selected. Antibodies against Pestivirus F were detected by a traditional in-house indirect immunofluorescence test against the culture-grown virus isolate, while for the detection of Pestivirus K-specific antibodies, a newly developed test system utilizing a chimeric construct of bovine viral diarrhea virus 1 (BVDV1; species Pestivirus A) containing the E1 and E2 encoding sequences of APPV was established. A total of 1115 samples originating from 122 farms located in seven German federal states were investigated. Antibodies against Bungowannah virus could not be detected, confirming the absence of this virus in other regions than the initially affected Australian pig farm complex. In contrast, antibodies against APPV were highly prevalent throughout Germany at both investigated time points. The seroprevalence at the state level fluctuated to some degree, but the overall percentage remained stable, as is to be expected for an endemic pestivirus lacking any form of control measures.

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Modelling the Evolution of COVID-19 in High-Incidence European Countries and Regions: Estimated Number of Infections and Impact of Past and Future Intervention Measures

Journal of Clinical Medicine ◽

10.3390/jcm9061825 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1825 ◽

Cited By ~ 3

Author(s):

Juan Fernández-Recio

Keyword(s):

Reproduction Number ◽

Mechanistic Model ◽

Control Measures ◽

European Countries ◽

Intervention Measures ◽

High Incidence ◽

Future Outcomes ◽

Long Term Impact ◽

The Impact

A previously developed mechanistic model of COVID-19 transmission has been adapted and applied here to study the evolution of the disease and the effect of intervention measures in some European countries and territories where the disease has had a major impact. A clear impact of the major intervention measures on the reproduction number (Rt) has been found in all studied countries and territories, as already suggested by the drop in the number of deaths over time. Interestingly, the impact of such major intervention measures seems to be the same in most of these countries. The model has also provided realistic estimates of the total number of infections, active cases and future outcomes. While the predictive capabilities of the model are much more uncertain before the peak of the outbreak, we could still reliably predict the evolution of the disease after a major intervention by assuming the subsequent reproduction number from the current study. A greater challenge is to foresee the long-term impact of softer intervention measures, but this model can estimate the outcome of different scenarios and help to plan changes for the implementation of control measures in a given country or region.

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Stakeholder Involvement in Outbreak Management

International Journal of Information Systems for Crisis Response and Management ◽

10.4018/ijiscram.2019070104 ◽

2019 ◽

Vol 11 (2) ◽

pp. 57-78

Author(s):

Magdalena M. Kraaij-Dirkzwager ◽

Lianne G. C. Schol ◽

Tjerk Jan Schuitmaker-Warnaar ◽

Aura Timen ◽

Jim E. Van Steenbergen

Keyword(s):

Time Pressure ◽

Communicable Disease ◽

Stakeholder Participation ◽

Stakeholder Involvement ◽

Disease Outbreaks ◽

Network Governance ◽

Control Measures ◽

Outbreak Management ◽

Collective Interest ◽

Infectious Disease Outbreaks

Infectious diseases remain a threat to public health, requiring the coordinated action of many stakeholders. Little has been written about stakeholder participation and approaches to sharing information, in dynamic contexts and under time pressure as is the case for infectious disease outbreaks. Communicable-disease specialists fear that delays in implementing control measures may occur if stakeholders are not included in the outbreak-management process. Two case studies described in this article show how the needs of stakeholders may vary with time and that early sharing of information takes priority over shared decision-making. The stakeholders itemized their needs and potential contributions in order to arrive at the collective interest of outbreak management. For this, the results suggest the potential for improvement through development of “network governance” including the effective sharing of information in large networks with varying needs. Outbreaks in which conflicting perceptions may occur among the stakeholders require particular attention.

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Public farms: hygiene and zoonotic agents

Epidemiology and Infection ◽

10.1017/s0950268807008072 ◽

2007 ◽

Vol 135 (7) ◽

pp. 1174-1183 ◽

Cited By ~ 12

Author(s):

A. E. HEUVELINK ◽

S. M. VALKENBURGH ◽

J. J. H. C. TILBURG ◽

C. VAN HEERWAARDEN ◽

J. T. M. ZWARTKRUIS-NAHUIS ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Human Exposure ◽

Public Awareness ◽

Zoonotic Diseases ◽

Control Measures ◽

Public And Private ◽

Faecal Material ◽

Standard Questionnaire ◽

Hygiene Measures

SUMMARYIn three successive years, we visited petting farms (n=132), care farms (n=91), and farmyard campsites (n=84), respectively, and completed a standard questionnaire with the objective of determining the hygienic status of these farms and describing hygiene measures implemented to reduce the risk of transmission of zoonotic agents from the animals to humans. For at least 85% of the farms, the overall impression of hygiene was recorded as good. However, more attention must be paid to: informing visitors on hygiene and handwashing, provision of handwashing facilities, and a footwear cleaning facility. Examination of samples of freshly voided faeces resulted in the detection of Shiga toxin-producingEscherichia coliO157 and/orSalmonellaspp. and/orCampylobacterspp. at almost two-thirds (64·9%) of the petting farms, and around half of the care farms (56·0%) and farmyard campsites (45·2%). These data reinforce the need for control measures for both public and private farms to reduce human exposure to livestock faeces and thus the risk of transmission of zoonotic diseases. Public awareness of the risk associated with handling animals or faecal material should be increased.

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Transmission and control in an institutional pandemic influenza A(H1N1) 2009 outbreak

Epidemiology and Infection ◽

10.1017/s0950268811001518 ◽

2011 ◽

Vol 140 (6) ◽

pp. 1102-1110 ◽

Cited By ~ 4

Author(s):

N. ARINAMINPATHY ◽

N. RAPHAELY ◽

L. SALDANA ◽

C. HODGEKISS ◽

J. DANDRIDGE ◽

...

Keyword(s):

High Risk ◽

Infection Control ◽

Pandemic Influenza ◽

Summer School ◽

Influenza A ◽

Control Measures ◽

Infection Control Measures ◽

Influenza A H1n1 ◽

Hygiene Measures ◽

The Impact

SUMMARYA pandemic influenza A(H1N1) 2009 outbreak in a summer school affected 117/276 (42%) students. Residential social contact was associated with risk of infection, and there was no evidence for transmission associated with the classroom setting. Although the summer school had new admissions each week, which provided susceptible students the outbreak was controlled using routine infection control measures (isolation of cases, basic hygiene measures and avoidance of particularly high-risk social events) and prompt treatment of cases. This was in the absence of chemoprophylaxis or vaccination and without altering the basic educational activities of the school. Modelling of the outbreak allowed estimation of the impact of interventions on transmission. These models and follow-up surveillance supported the effectiveness of routine infection control measures to stop the spread of influenza even in this high-risk setting for transmission.

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Summary of 11 Years of Enteric Outbreak Investigations and Criteria To Initiate an Investigation, Province of Quebec, 2002 through 2012

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-530 ◽

2014 ◽

Vol 77 (9) ◽

pp. 1563-1570 ◽

Cited By ~ 5

Author(s):

COLETTE GAULIN ◽

ANDREA CURRIE ◽

GENEVIÈVE GRAVEL ◽

MEGHAN HAMEL ◽

MARIE-ANDREE LEBLANC ◽

...

Keyword(s):

Odds Ratio ◽

Control Measure ◽

Descriptive Analysis ◽

Disease Outbreaks ◽

Disease Outbreak ◽

Control Measures ◽

Primary Control ◽

Enteric Disease ◽

Health Authorities ◽

Outbreak Investigations

This article presents a retrospective analysis of enteric disease outbreak investigations led by or conducted in collaboration with provincial health authorities in the Province of Quebec from 2002 through 2012. Objectives were to characterize enteric disease outbreaks, quantify and describe those for which a source was identified (including the control measures implemented), identify factors that contributed to or impeded identification of the source, and recommend areas for improvement in outbreak investigations (including establishment of criteria to initiate investigations). A descriptive analysis of enteric disease outbreak summaries recorded in a provincial database since 2002 was conducted, and corresponding outbreak reports were reviewed. Among 61 enteric disease outbreaks investigated, primary pathogens involved were Salmonella (46%), Escherichia coli O157:H7 (25%), and Listeria monocytogenes (13%). Sources were identified for 37 (61%) of 61 of the outbreaks, and descriptive studies were sufficient to identify the source for 26 (70%) of these. During the descriptive phase of the investigation, the causes of 21 (81%) of 26 outbreaks were identified by promptly collecting samples of suspected foods based on case interviews. Causes of outbreaks were more likely to be detected by weekly surveillance or alert systems (odds ratio = 6.0, P = 0.04) than by serotyping or molecular typing surveillance and were more likely to be associated with a common event or location (odds ratio = 11.0, P = 0.023). Among the 37 outbreaks for which causes were identified, 24 (65%) were associated with contaminated food, and recalls were the primary control measure implemented (54%). Review of enteric outbreaks investigated at the provincial level in Québec has increased the province's ability to quantify success and identify factors that can promote success. Multiple criteria should be taken into account to identify case clusters that are more likely to be resolved.

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Is Nigeria really on top of COVID-19? Message from effective reproduction number

10.1101/2020.05.16.20104471 ◽

2020 ◽

Author(s):

Adeshina Israel Adekunle ◽

Oyelola Adegboye ◽

Ezra Gayawan ◽

Emma McBryde

Keyword(s):

Public Health ◽

Compartmental Model ◽

Reproduction Number ◽

Transmission Rate ◽

Credible Interval ◽

Control Measures ◽

Maximum Value ◽

Intervention Measures ◽

Death Cases ◽

Epidemiological Parameters

Following the importation of Covid-19 into Nigeria on the 27 February 2020 and then the outbreak, the question is: how do we anticipate the progression of the ongoing epidemics following all the intervention measures put in place? This kind of question is appropriate for public health responses and it will depend on the early estimates of the key epidemiological parameters of the virus in a defined population. In this study, we combined a likelihood-based method using a Bayesian framework and compartmental model of the epidemic of Covid-19 in Nigeria to estimate the effective reproduction number (R(t)) and basic reproduction number (R_0). This also enables us to estimate the daily transmission rate (β) that determines the effect of social distancing. We further estimate the reported fraction of symptomatic cases. The models are applied to the NCDC data on Covid-19 symptomatic and death cases from 27 February 2020 and 7 May 2020. In this period, the effective reproduction number is estimated with a minimum value of 0.18 and a maximum value of 1.78. Most importantly, the R(t) is strictly greater than one from April 13 till 7 May 2020. The R_0 is estimated to be 2.42 with credible interval: (2.37, 2.47). Comparing this with the R(t) shows that control measures are working but not effective enough to keep R(t) below one. Also, the estimated fractional reported symptomatic cases are between 10 to 50%. Our analysis has shown evidence that the existing control measures are not enough to end the epidemic and more stringent measures are needed.

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Fungicide efficacy in peach rusty spot control in Serbia

Pesticidi i fitomedicina ◽

10.2298/pif1003241d ◽

2010 ◽

Vol 25 (3) ◽

pp. 241-249 ◽

Cited By ~ 3

Author(s):

Nenad Dolovac ◽

Novica Miletic ◽

Goran Aleksic ◽

Dusan Savic ◽

Svetlana Zivkovic ◽

...

Keyword(s):

Disease Incidence ◽

Natural Infection ◽

Control Measures ◽

The Past ◽

Protection Method ◽

Technical Control ◽

Efficient Control ◽

Significant Yield ◽

Second Year

Rusty Spot has long been known as a harmful peach disease in many parts of the world. During the past several years, rusty spot infection of the late-maturing peach cultivars (Summerset, Suncrest, Fayette and O?Henry) caused significant yield losses in Serbia. Although the etiology of the disease is still unknown, there are numerous studies attempting to set a strategy for its control and recommend appropriate chemical and other peach protection methods. However, because of specific environmental conditions in Serbia, recommended protection method using repeated fungicide treatments, starting from petal fall, did not prove to be efficient and the rate of infection in some susceptible peach cultivars reached 100%. In 2003 and 2004 a field trial was conducted in order to test the efficacy of fungicides (a.i. kresoxim-methyl, flusilazole and sulfur) for the efficient control of Rusty Spot epidemics. The trial was carried out under conditions of natural infection on the peach cv. Summerset at the locality of Bela Crkva, Serbia. In the untreated control plots, high disease incidence was recorded with the percentage of affected fruit surface ranging from 33.5% in the first, up to the 35.4% in the second year of the trail. Among fungicides included in the trial, kresoxim-methyl proved to be the most efficient (90.25% in the first and 91.12% in the second year of the trial), flusilazole exhibited lower efficacy (87.28% and 80.61%, respectively) while sulfur was the least efficient (82.33% and 80.30%, respectively). Determination of the most efficient fungicide for the peach rusty spot control in Serbia provides basic information for further investigations which will include optimization of treatment terms, as well as additional agro-technical control measures.

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