scholarly journals Mycoplasma gallisepticum infection dynamics in a house finch population: seasonal variation in survival, encounter and transmission rate

2004 ◽  
Vol 73 (4) ◽  
pp. 651-669 ◽  
Author(s):  
Cristina R. Faustino ◽  
Christopher S. Jennelle ◽  
Veronique Connolly ◽  
Andrew K. Davis ◽  
Elliott C. Swarthout ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Transmission Rate ◽  
Mycoplasma Gallisepticum ◽  
House Finch ◽  
Infection Dynamics

scholarly journals Infection dynamics and persistence of hepatitis E virus on pig farms – a review

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
M. Meester ◽  
T. J. Tobias ◽  
M. Bouwknegt ◽  
N. E. Kusters ◽  
J. A. Stegeman ◽  
...  
Keyword(s):  
Risk Factors ◽  
Hepatitis E Virus ◽  
Risk Mitigation ◽  
Transmission Rate ◽  
Hepatitis E ◽  
Main Body ◽  
Genotype 3 ◽  
Infection Dynamics ◽  
Pig Farms ◽  
Slaughter Pigs

Abstract Background Hepatitis E virus (HEV) genotype 3 and 4 is a zoonosis that causes hepatitis in humans. Humans can become infected by consumption of pork or contact with pigs. Pigs are the main reservoir of the virus worldwide and the virus is present on most pig farms. Main body Though HEV is present on most farms, the proportion of infected pigs at slaughter and thus the level of exposure to consumers differs between farms and countries. Understanding the cause of that difference is necessary to install effective measures to lower HEV in pigs at slaughter. Here, HEV studies are reviewed that include infection dynamics of HEV in pigs and on farms, risk factors for HEV farm prevalence, and that describe mechanisms and sources that could generate persistence on farms. Most pigs become infected after maternal immunity has waned, at the end of the nursing or beginning of the fattening phase. Risk factors increasing the likelihood of a high farm prevalence or proportion of actively infected slaughter pigs comprise of factors such as farm demographics, internal and external biosecurity and immunomodulating coinfections. On-farm persistence of HEV is plausible, because of a high transmission rate and a constant influx of susceptible pigs. Environmental sources of HEV that enhance persistence are contaminated manure storages, water and fomites. Conclusion As HEV is persistently present on most pig farms, current risk mitigation should focus on lowering transmission within farms, especially between farm compartments. Yet, one should be aware of the paradox of increasing the proportion of actively infected pigs at slaughter by reducing transmission insufficiently. Vaccination of pigs may aid HEV control in the future.

scholarly journals Potential impact of seasonal forcing on a SARS-CoV-2 pandemic

2020 ◽  
Author(s):  
Richard A. Neher ◽  
Robert Dyrdak ◽  
Valentin Druelle ◽  
Emma B. Hodcroft ◽  
Jan Albert
Keyword(s):  
Seasonal Variation ◽  
Infection Control ◽  
Transmission Rate ◽  
Health Care Systems ◽  
Control Measures ◽  
Rate Variation ◽  
Small Peak ◽  
Infection Control Measures ◽  
Care Systems ◽  
Novel Coronavirus

A novel coronavirus (SARS-CoV-2) first detected in Wuhan, China, has spread rapidly since December 2019, causing more than 80,000 confirmed infections and 2,700 fatalities (as of Feb 27, 2020). Imported cases and transmission clusters of various sizes have been reported globally suggesting a pandemic is likely.Here, we explore how seasonal variation in transmissibility could modulate a SARS-CoV-2 pandemic. Data from routine diagnostics show a strong and consistent seasonal variation of the four endemic coronaviruses (229E, HKU1, NL63, OC43) and we parameterize our model for SARS-CoV-2 using these data. The model allows for many subpopulations of different size with variable parameters. Simulations of different scenarios show that plausible parameters result in a small peak in early 2020 in temperate regions of the Northern Hemisphere and a larger peak in winter 2020/2021. Variation in transmission and migration rates can result in substantial variation in prevalence between regions.While the uncertainty in parameters is large, the scenarios we explore show that transient reductions in the incidence rate might be due to a combination of seasonal variation and infection control efforts but do not necessarily mean the epidemic is contained. Seasonal forcing on SARS-CoV-2 should thus be taken into account in the further monitoring of the global transmission. The likely aggregated effect of seasonal variation, infection control measures, and transmission rate variation is a prolonged pandemic wave with lower prevalence at any given time, thereby providing a window of opportunity for better preparation of health care systems.

scholarly journals Dynamics of Conjunctivitis and Mycoplasma Gallisepticum Infections in House Finches

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 327-333 ◽  
Author(s):  
Barry K. Hartup ◽  
Jean M. Bickal ◽  
Andre A. Dhondt ◽  
David H. Ley ◽  
George V. Kollias
Keyword(s):  
Breeding Season ◽  
Annual Variation ◽  
Seasonal Fluctuation ◽  
Host Density ◽  
Mycoplasma Gallisepticum ◽  
Disease Prevalence ◽  
Significant Decline ◽  
Carpodacus Mexicanus ◽  
House Finch ◽  
House Finches

Abstract Conjunctivitis, an infectious disease caused by Mycoplasma gallisepticum (MG), has produced a significant decline in eastern House Finches (Carpodacus mexicanus) of North America. In this paper, we present findings from two complementary studies designed to clarify annual and seasonal trends of MG infections in House Finches from the northeastern United States. The first was a field study of House Finches common to urban and residential habitat from Mercer County, New Jersey. We documented conjunctivitis in 11% (188/1,651) of the birds examined. Conjunctivitis prevalence in House Finches ranged from 0 to 43% per month, and exhibited marked seasonal fluctuation (elevations during fall and winter months and lower disease prevalence during the breeding season). There was excellent intermethod agreement on disease prevalence when measured by either presence of physical signs (conjunctivitis) or MG infection (kappa = 0.75). During the peak of the breeding season (April through June), conjunctivitis was present in a greater proportion of males lacking a cloacal protuberance than males with a cloacal protuberance (P < 0.01), but was similar between breeding and nonbreeding females. The second study, a volunteer survey, revealed the proportion of northeastern U.S. monitoring sites with at least one diseased House Finch each month ranged from a peak of 59% (August 1995) to a minimum of 12% (July 1999). Subsequent to the epidemic peak of disease in 1995, a series of recurring cycles occurred, with elevations in those proportions noted in late fall and winter and minima during the breeding season. Mycoplasmal conjunctivitis now appears endemic among House Finches of that region and demonstrates dynamics consistent with annual variation in host density.

scholarly journals Differing House Finch Cytokine Expression Responses to Original and Evolved Isolates of Mycoplasma gallisepticum

2018 ◽  
Vol 9 ◽  
Author(s):  
Michal Vinkler ◽  
Ariel E. Leon ◽  
Laila Kirkpatrick ◽  
Rami A. Dalloul ◽  
Dana M. Hawley
Keyword(s):  
Mycoplasma Gallisepticum ◽  
Cytokine Expression ◽  
House Finch

scholarly journals Attenuated Phenotype of a Recent House Finch-Associated Mycoplasma gallisepticum Isolate in Domestic Poultry

2017 ◽  
Vol 85 (6) ◽  
Author(s):  
K. Pflaum ◽  
E. R. Tulman ◽  
J. Beaudet ◽  
X. Liao ◽  
K. V. Dhondt ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Mycoplasma Gallisepticum ◽  
Respiratory Pathogen ◽  
House Finch ◽  
Eastern United States ◽  
Content Type ◽  
House Finches ◽  
Domestic Poultry ◽  
Significant Difference ◽  
The Difference

ABSTRACT Mycoplasma gallisepticum, known primarily as a respiratory pathogen of domestic poultry, has emerged since 1994 as a significant pathogen of the house finch (Haemorhous mexicanus) causing severe conjunctivitis and mortality. House finch-associated M. gallisepticum (HFMG) spread rapidly and increased in virulence for the finch host in the eastern United States. In the current study, we assessed virulence in domestic poultry with two temporally distant, and yet geographically consistent, HFMG isolates which differ in virulence for house finches—Virginia 1994 (VA1994), the index isolate of the epidemic, and Virginia 2013 (VA2013), a recent isolate of increased house finch virulence. Here we report a significant difference between VA1994 and VA2013 in their levels of virulence for chickens; notably, this difference correlated inversely to the difference in their levels of virulence for house finches. VA1994, while moderately virulent in house finches, displayed significant virulence in the chicken respiratory tract. VA2013, while highly virulent in the house finch, was significantly attenuated in chickens relative to VA1994, displaying less-severe pathological lesions in, and reduced bacterial recovery from, the respiratory tract. Overall, these data indicate that a recent isolate of HFMG is greatly attenuated in the chicken host relative to the index isolate, notably demonstrating a virulence phenotype in chickens inversely related to that in the finch host.

scholarly journals Temperature and population density influence SARS-CoV-2 transmission in the absence of nonpharmaceutical interventions

2021 ◽  
Vol 118 (25) ◽  
pp. e2019284118
Author(s):  
Thomas P. Smith ◽  
Seth Flaxman ◽  
Amanda S. Gallinat ◽  
Sylvia P. Kinosian ◽  
Michael Stemkovski ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Population Density ◽  
Transmission Rate ◽  
The United States ◽  
Transmission Intensity ◽  
Epidemiological Modeling ◽  
Policy Interventions ◽  
Using Data ◽  
Nonpharmaceutical Interventions ◽  
The Impact

As COVID-19 continues to spread across the world, it is increasingly important to understand the factors that influence its transmission. Seasonal variation driven by responses to changing environment has been shown to affect the transmission intensity of several coronaviruses. However, the impact of the environment on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains largely unknown, and thus seasonal variation remains a source of uncertainty in forecasts of SARS-CoV-2 transmission. Here we address this issue by assessing the association of temperature, humidity, ultraviolet radiation, and population density with estimates of transmission rate (R). Using data from the United States, we explore correlates of transmission across US states using comparative regression and integrative epidemiological modeling. We find that policy intervention (“lockdown”) and reductions in individuals’ mobility are the major predictors of SARS-CoV-2 transmission rates, but, in their absence, lower temperatures and higher population densities are correlated with increased SARS-CoV-2 transmission. Our results show that summer weather cannot be considered a substitute for mitigation policies, but that lower autumn and winter temperatures may lead to an increase in transmission intensity in the absence of policy interventions or behavioral changes. We outline how this information may improve the forecasting of COVID-19, reveal its future seasonal dynamics, and inform intervention policies.

Sign in / Sign up

Export Citation Format

Share Document