Search results for "disease outbreak"

Nowcasting COVID‐19 incidence indicators during the Italian first outbreak

2020

A novel parametric regression model is proposed to fit incidence data typically collected during epidemics. The proposal is motivated by real-time monitoring and short-term forecasting of the main epidemiological indicators within the first outbreak of COVID-19 in Italy. Accurate short-term predictions, including the potential effect of exogenous or external variables are provided. This ensures to accurately predict important characteristics of the epidemic (e.g., peak time and height), allowing for a better allocation of health resources over time. Parameter estimation is carried out in a maximum likelihood framework. All computational details required to reproduce the approach and replica…

Low-altitude outbreaks of human fascioliasis related with summer rainfall in Gilan province, Iran

2011

Following human fascioliasis outbreaks in 1988 and 1999 in Gilan province, northern Iran, efforts are now made to shed light on the seasonal pattern of fascioliasis transmission in this endemic area, taking into account snail host populations, climatic conditions and human cases. Populations of the intermediate host snail (Lymnaea spp.) peak in May and November, while there is a fourfold increase in the rate of human fascioliasis in February compared to that of September. Transmission is likely to occur mainly in late autumn and sporadically in late spring. Rainfall, seasonally analysed in periods of 3 years, indicates that accumulated summer rainfall may be related with the 1988 and 1999 h…

Outside-host growth of pathogens attenuates epidemiological outbreaks.

2012

Opportunist saprotrophic pathogens differ from obligatory pathogens due to their capability in host-independent growth in environmental reservoirs. Thus, the outside-host environment potentially influences host-pathogen dynamics. Despite the socio-economical importance of these pathogens, theory on their dynamics is practically missing. We analyzed a novel epidemiological model that couples outside-host density-dependent growth to host-pathogen dynamics. Parameterization was based on columnaris disease, a major hazard in fresh water fish farms caused by saprotrophic Flavobacterium columnare. Stability analysis and numerical simulations revealed that the outside-host growth maintains high pr…

Molecular epidemiology and forensic genetics: application to a hepatitis C virus transmission event at a hemodialysis unit.

2002

Molecular phylogenetic analyses are frequently used in epidemiologic testing, although only occasionally in forensics. Their acceptability is hampered by a lack of statistical confidence in the conclusions. However, maximum likelihood testing provides a sound statistical framework for the testing of phylogenetic hypotheses relevant for forensic analysis. We present the results of applying this method to a small hepatitis C outbreak produced in a hospital hemodialysis unit that involved 6 patients. Polymerase chain reaction products from a 472-nt fragment of the E1-E2 region, including the hypervariable region, HVR-1, of the hepatitis C virus genome were cloned, and an average of 10 clones/p…

Recombination drives genome evolution in outbreak-related Legionella pneumophila isolates.

2014

Legionella pneumophila is a strictly environmental pathogen and the etiological agent of legionellosis. It is known that non-vertical processes have a major role in the short-term evolution of pathogens, but little is known about the relevance of these and other processes in environmental bacteria. We report the whole-genome sequencing of 69 L. pneumophila strains linked to recurrent outbreaks in a single location (Alcoy, Spain) over 11 years. We found some examples where the genome sequences of isolates of the same sequence type and outbreak did not cluster together and were more closely related to sequences from different outbreaks. Our analyses identify 16 recombination events responsibl…

Genotyping of a nosocomial outbreak of pandemic influenza A/H1N1 2009

2011

Background: Epidemiological surveys have revealed outbreaks of pandemic influenza A (H1N1) 2009 in several different contexts. Molecular characterization of the influenza virus could help to provide a more accurate description of these outbreaks. Objective: To genotype pandemic influenza A (H1N1) 2009 isolates from an epidemiologically defined nosocomial outbreak. Study design: We sequenced the neuraminidase (NA) and hemagglutinin (HA) influenza A (H1N1) 2009 genes from ten HIV-positive patients involved in an epidemiologically defined outbreak in the Clinical Microbiology and Infectious Diseases (CMID) Department. Sequences were aligned to search for specific genetic features of the involv…

Glochidial infection by the endangered Margaritifera margaritifera (Mollusca) increased survival of salmonid host (Pisces) during experimental Flavob…

2021

AbstractCo-infections are common in host-parasite interactions, but studies about their impact on the virulence of parasites/diseases are still scarce. The present study compared mortality induced by a fatal bacterial pathogen, Flavobacterium columnare between brown trout infected with glochidia from the endangered freshwater pearl mussel, Margaritifera margaritifera, and uninfected control fish during the parasitic period and after the parasitic period (i.e. glochidia detached) in a laboratory experiment. We hypothesised that glochidial infection would increase host susceptibility to and/or pathogenicity of the bacterial infection. We found that the highly virulent strain of F. columnare c…

An outbreak of HBV and HCV infection in a paediatric oncology ward: Epidemiological investigations and prevention of further spread

2003

Hospital-acquired hepatitis B (HBV) and C virus (HCV) infections continue to occur despite increased awareness of this problem among the medical community. One hundred six patients were infected in a haematology oncology ward for children, over the time period 1996 to 2000. Serum samples from 45 such patients and 3 from infected medical personnel were used for nucleic acid amplification. HBV core, as well as HCV core and hypervariable region 1 (HVR1) nucleotide sequences, were analysed by phylogenetic tree analysis, in order to characterise the epidemiological pattern of viral transmission on the ward. Samples from 32 patients were positive for HBV-DNA or HCV-RNA by PCR. Ten patients were p…

The international Ebola response: heroes and bystanders in the chronicle of an epidemic foretold.

2014

The Deadly Quartet (Covid-19, Old Age, Lung Disease, and Heart Failure) Explains Why Coronavirus-Related Mortality in Northern Italy Was So High

2020

Since its outbreak in China at the end of 2019, the new coronavirus disease (COVID-19) was characterized by both easy spreading and high mortality. The latter proved to be way more elevated in the North of Italy -with a peak of 18.4% in region Lombardia and even 31% in the city of Bergamo and surrounding county- than in the rest of the world. In an attempt to conceptualize the reasons for such a dramatic situation, four key elements have been identified: COVID-19 itself, old age, lung disease, and heart failure. Their harmful combination has been named “The deadly quartet”. The underlying risk factors, among which a lot of them are distinctive features of the population in northern Italy, …