Questions tagged [epidemiology]
The study of the distribution, incidence, and potential control of a disease.
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Reproduction number in SAIQR model
$$ \dot S (t)=\Lambda-\beta_1 S(t)A(t)-\beta_2S(t)I(t)-\mu S(t)$$
$$ \dot A (t)= \beta_1 S(t)A(t)+\beta_2S(t)I(t)-(\mu+\alpha) A(t)$$
$$ \dot I (t)=\alpha A(t)-(\mu+\theta)I(t)$$
$$ \dot Q (t)=\theta ...
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Was there a flu season in paleolithic times?
In temperate climates, flu viruses rise and recede with winter. This is for a number of reasons, including lack of vitamin D production in darkness (which weakens the immune system), dry air (humidity ...
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Is taking antimalarial drugs a confounder when exposure is "having sprayed insecticide in the house" and the outcome is "malaria infection"
Morning all,
I am curious as to whether the concept of confounding applies in the following situation: Specifically I want to know if "taking antimalarials" is a confounding variable.
The ...
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Why is China experiencing such a surge in acute cases of COVID?
The majority of western nations have lifted most if not all COVID restrictions, however we are not seeing a massive rise in serious cases of COVID-19.
Why is it different in China? Do they have a ...
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Can the Monkeypox virus be spread by mosquitoes?
I am wondering if the Monkeypox virus could be spread by mosquitoes since it is part of the Smallpox family.
While doing some online research on this possibility, I came across this abstract taken ...
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Why don't viruses reach broad concentration outdoors in a city like allergens?
Why don't airborne viruses reach concentrations that infect most people vulnerable outdoors in a city the way an allergen can cause inflammation to everyone sensitive to it. Both are (often) ...
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Can SARS-COV2 strain competition be modelled by inter-species lotka volterra equations?
Currently studying infectious diseases epidemiology and never studied ecology. But I was wondering if the interspecies Lotka Volterra equations could model and explain strain dominance.
r = could be ...
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Does specific immunity affect the incubation period of viruses?
My interest was inspired by the observed variation in incubation times for different strains of Covid-19, however I ask the question in the broader sense as it seems hard to find an answer in general.
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Would this be classified as a cross-sectional study design?
Let's say I'm conducting a study in which persons recently diagnosed with an infectious disease were recruited to provide a variety of different specimens and answer standardized clinical survey ...
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Why do some viruses get deadlier over time?
I was wondering what reasons are that make some viruses become more lethal over time.
By "more lethal", I am not referring to acquiring more mutations which make the virus more infectious ...
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Fluctuations in disease burden of respiratory viruses (especially influenza/coronaviruses)
Compared to peaks in terms of disease burden (morbidity and mortality, or incidence of severely symptomatic cases and deaths caused by a viral strain within a population), is the relatively light ...
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How can the recurrence risk ratio be calculated?
The recurrence risk ratio is calculated as follows:
$$ \lambda_s = \frac{\text{risk of sibling}}{\text{risk in population}}$$
where the risk of sibling refers to the risk that a sibling has to get the ...
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Why there aren't any pandemic diseases by prions?
Learning biology in school, I became interested in the fact that there aren't any diseases by prions which are globally infectious (as far as I know), unlike diseases by viruses (ex. COVID-19, SARS ...
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Virus variant transmissibility: empirical data or spike protein shape?
Well first I am not in the field of Biology or Medical Sciences. Since these days we are waiting scientists to tell us if the Indian variant of SARS Cov 2 is more transmissible than the original virus,...
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Which viruses still present today caused a deadly pandemic/epidemic in the past?
The current Covid-19 pandemic and its virus Sars-Cov-2 can be dangerous, especially for vulnerable groups like the elders. But however, I have seen studies that this virus become less dangerous in the ...
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Relationship between BMI and age?
I'm trying to study how age as a confounder may affect the relationship between commute mode and BMI (and design a research proposal).
To explain age as a potential confounder, I compared age to ...
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Covid-19 is a respiratory illness. So how could you catch it by touch?
The U.S. department of agriculture put out a statement in February 2021 in which they wished to underscore that at the time there is no epidemiologic or scientific information that COVID-19 spreads ...
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The probability meaning of Covid variants
In the CDC webpage about Covid-19's variants the next sentence appears:
This (the United Kingdom) variant spreads more easily and quickly
than other variants.
In the ECDC paper about Covid-19's ...
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How are vaccines mass-produced?
I have a background in product design and so am familiar with with how most things are mass-produced — food, machines, etc. But I've been able to find very little information on how vaccines are mass-...
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What is the consensus in the scientific community over COVID-19's mode of transmission?
I've read from many news and scientific sources that COVID spreads primarily through respiratory droplets, but I've also read multiple sources that have said we don't entirely know yet. Is it fomites, ...
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Do partial (nighttime) curfews curb the spread of epidemics (and via which mechanisms)? [closed]
Do partial (e.g., nighttime) curfews curb the spread of epidemics?
What is the (epidemiological) mechanism by which partial curfews curb the spread of epidemics?
Is there evidence from past or present ...
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Are there any examples of viruses that have jumped from reptile to human?
I know that there are plenty of examples of zoonosis occurring from reptiles to humans that involve bacterial pathogens, (e.g. Salmonella) but are there any instances of viruses being transferred from ...
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COVID-19 deaths by year of birth?
Are there (global, country, etc.) data of COVID-19 deaths (or hospitalization) by year of birth? I was able to found them only by "age group", the meaning of this being usually an interval ...
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What kind of people are more likely to catch COVID-19?
It is well known that people of old age or with respiratory problems are more vulnerable by the effects of COVID-19. However, I wasn't able to find information on any similar trends on catching the ...
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About how many covid-19 virus particles is required in the human body before infection and sickness follows?
Our immune systems are often able to destroy germs and virus particles.
About how many of them does it take to make a 70 year old healthy male sick ? Any ideas ?
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Why is there no herd immunity against common cold coronaviruses?
In discussions of herd immunity against SARS-CoV-2 the underlying assumption usually appears to be that the virus basically stops spreading once a sufficient percentage of the population has overcome ...
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How to fit simulated with measured data having systematic errors?
Consider a given time series of measured data, i.e. the number of persons tested positive for COVID-19. And consider a simulation - consisting of a model, possibly fed with some parameters estimated a ...
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Are the social-distancing measures implemented against SARS-CoV-2 also suppressing the spread of other viruses?
With social-distancing measures being implemented in many countries I would expect other viruses, like the ones that cause seasonal flus, to have also a hard time propagating in these circumstances. ...
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Factors of infection rate
I refer to J.H. Jones' Notes on R0.
Preliminaries
The standard SIR model consists of a system of three differential equations
$$ds/dt = -\beta s i$$
$$di/dt = \beta s i - \nu i$$
$$dr/dt = \nu i$...
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Interpreting the reciprocal of $R_0$
$R_0$ is the average number of secondary cases arising from a single infectious individual in a fully susceptible population.
In many of the compartmental models for epidemiology, the parameter $\...
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How to model social structure in SIR models
I refer to J.H. Jones' Notes on R0.
More details in this question at Mathematics SE: How does the reproduction number depend on characteristics of the physical contact graph of a population?
The ...
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The role of duration of infectiousness in SIR models
I refer to J.H. Jones' Notes on R0.
The basic SIR model - as described in Jones' Notes - considers three factors that make up the reproduction number:
$\tau$ = the transmissibility (i.e., ...
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Why are men more susceptible to severe COVID-19?
It seems that globally, men are more susceptible to severe COVID-19 than women:
https://www.theguardian.com/world/2020/mar/26/men-are-much-more-likely-to-die-from-coronavirus-but-why
This is seen in ...
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Do we know if dogs are asymptomatic transmiters of sars-cov-2?
Dogs do not use mask when going for a walk nor they observe the security distance. On the contrary, they frequently join their noses, and put their noses where other dogs had put them before or had ...
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COVID-19 Infection rate related to population size?
Recently, in the UK's daily government briefing they started showing the graphs that compare national death rates, adjusted by the population size of each country.
I understand the various reasons ...
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Is there a vaccine against the plague (Yersinia pestis)?
There seems to be recurrent events of infections of the plage (Yersinia pestis), from the well known Justinian plague to the Black Death and to recent years. In fact, two cases were reported in China ...
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What does (deaths / (resolved + deaths)) describe in an emerging epidemic?
It would seem in a emerging epidemic, where the time to resolve a disease is long, an evaluation might be used such as:
(predictive mortality rate) = (deaths) / (deaths + resolved)
Is this a ...
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What happens to a virus SARS-CoV-2 on an object?
Many articles say that "the coronavirus" — they probably speak of the SARS-CoV-2 — can "remain alive" for so many hours on some surfaces, so many days on some other surfaces. For example, "the virus ...
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Why does the SARS-CoV2 virus not remain infectious forever? Or does it?
Given that the majority of biologists do not currently consider viruses to be alive, a virus can never die. It can, however, get destroyed by long exposures to soapy water, alcohol, and apparently ...
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How verified experimentally is the Marginal Value Theorem for viruses?
Reading some Stanford notes on R0, they get to MVT and optimal virulence:
Consider a directly-transmitted infection from which there is no recovery (e.g., Herpes Simplex). The population ...
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Can swarming locusts act as a vector for any human pathogens?
What human pathogens can the locusts currently swarming in Africa act as a vector for?
E.g. can the locust swarm 'become a reservoir for' SARS-CoV-2? Measles? Ebola?
user4466
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Why do some viruses cease being a problem even though no vaccine or cure is found?
No vaccine or cure has been found for SARS-CoV or MERS-CoV yet the world is not too concerned about them. How can it be? Did all people who had those viruses die or do viruses just randomly decide to ...
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Could an exposure to a small amount of viruses result in an easier course of the disease?
According to Gunther Hartmann (Professor of Clinical Chemistry and Pharmacology at the University of Bonn) cited in this article (Süddeutsche Zeitung, in German)
Die Zahl der Erreger hat bei ...
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Are specific primers or detectors, or both, used in COVID-19 tests?
I am trying to learn about the rRT-PCR testing procedure used to test for COVID-19, but I am slightly confused on one point. Are highly specific primers used with a non-specific detector, or are ...
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How likely is to develop an infection from a single virion entering a single cell? [closed]
Is there any research (including mathematical or computational modelling) regarding how likely it is to infect an organism starting from a single virion entering a single cell?
I am interested in any ...
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Does the Abbott ID NOW coronavirus test return a positive result if you take it while you're still in the incubation period? [closed]
It seems like Abbott's ID Now test works by detecting the virus directly as opposed to checking for antibodies? If the test result is negative does that mean you don't have the virus? Or does that not ...
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If rabies always kills its hosts, must there be some animal that is an asymptomatic carrier?
I searched a lot on the Internet, but I am not clear about the spread of the rabies virus. As I understand, rabies kills any animal it infects—cats, dogs, foxes, bats, humans. If it kills all of its ...
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Do we know of any "species ending bugs"?
Are we aware of a "bug" (virus, bacterium, prion, ...) that has completely exterminated an entire species? Either through direct observation or maybe some form of archeological evidence? If not, are ...
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Can far-UVC light be safely used as germicide? (help understanding a paper)
I've been trying to familiarize myself with the literature on far UVC light as a germicide. My question mostly pertains to figure 4 of this paper. The paper investigates the efficacy of 207 nm light ...
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If every person between 15-60 had an immune system equal to the healthiest people, would this affect the spread of coronavirus? [closed]
Has anyone calculated the speed or breadth of the spread of something like coronavirus (or any cold, flu, airborne pathogen) based on how well the population can master the virus with their immune ...
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