42 votes
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Why do diseases in the tap water of developing countries affect people from developed countries more?

You can expect that someone drinking from a water source regularly will develop immunity to the pathogens in that water source by being repeatedly exposed to them. However, it's not quite right to say ...
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28 votes
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Loss of taste and smell during a SARS-CoV-2 infection

This is not completely clear to say the least, but there are some hints. Please keep in mind that there was not much time for extensive research, since this disease is still quite new. What seems ...
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9 votes
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We know that the hepatitis C virus can live on surfaces for at least six weeks. Maybe longer. The infectivity study ended after just six weeks; why?

They ran out of samples Their test is destructive, they can't test the same sample twice. They planned out a number of samples to test for each time period and tested them. At the end of six weeks, ...
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9 votes
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Is COVID-19 more deadly than swine flu?

“Swine flu” is an obsolete name. The official name for the virus that was briefly called “swine flu” is “H1N1pdm09”. H1N1pdm09 has a mortality rate of around 0.01-0.1%. That’s roughly 10- to 20-...
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9 votes
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Acquiring Covid-19 vaccination through kissing with viral vector vaccinated person

No, this is not possible, as the vectors used for the vaccination cannot replicate anymore. Some of the genes necessary for this step have been removed from the viral genome to prevent the ...
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9 votes

Why do OX5034 GM mosquitos require the presence of tetracycline to survive? What does the drug do in this case?

They don't go into any detail on the sites you link to and I don't have time to look into patents, but from the context it sounds like they may be using a tetracycline repressible promoter. This is ...
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  • 5,292
9 votes

How does the first organism infected by a disease get infected?

Viruses evolve like all other biological species. The family of SIVs that gave rise to HIV goes back millions of years across many hosts. Just like you can build a "family tree" out of ...
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7 votes
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Did most pandemics originate from Asia/China?

According to Merriam-Webster Dictionary a Pandemic is: an outbreak of a disease that occurs over a wide geographic area and affects an exceptionally high proportion of the population : a pandemic ...
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6 votes

Why are vaccines containing attenuated microorganisms preferable to those containing dead microorganisms instead?

It's not necessarily true that attenuated vaccines are "preferable" to killed vaccines. It's a case by case basis. In some cases one or the other simply isn't possible or practical. It may not be ...
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6 votes

Can a vaccine or antidote be administrated via gases or sprays?

There are a number of currently used aerosolized vaccines throughout the world. Generally, these are studied and administered in single individual doses. There are advocates for the use of larger, ...
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  • 8,691
6 votes

Does avoiding medication that alleviates symptoms shorten the length of a cold?

It is plausible but by no means established that antipyretics (fever suppressors) in particular could increase the duration of infection/symptoms, because fever is part of a functional immune response....
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6 votes
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what will be the effect of cockroach bite?

I have reared cockroaches by the thousands, for years. Three species, but mainly the infamous Periplaneta americana which I am sure everyone has at least heard about (see picture at the end). First ...
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6 votes
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Where can I find disease diagnosis datasets?

CDC Wonder, a health database of the US Center of Disease Control and Prevention (CDC), has weekly data for Nationally Notifiable Infectious Diseases and Conditions, United States: Weekly Tables from ...
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6 votes
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Why do gram-negative bacteria attack the digestive system more than gram-positive ones?

Gastrointestinal infections can be caused by Gram positive and negative bacteria: Gram-positive: Staphylococcus aureus Clostridium difficile, botulinum and perfringens Listeria monocytogenes ...
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6 votes
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Can an infectious diseases come from a plant?

Question “Are there viruses that infect plants that can mutate to infect humans?” Answer None appear to have been reported so far. It is difficult to provide supporting evidence for an ...
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6 votes
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Why do OX5034 GM mosquitos require the presence of tetracycline to survive? What does the drug do in this case?

The other answers are correct and on the right track, but I will expand on them with the specific mechanism for these mosquitos. The following paper discusses the engineering behind strain OX513A upon ...
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  • 17.5k
6 votes

Why did Rivers replace Koch's postulates?

If you read his 1937 article, Rivers himself makes a case for why Koch's postulates are too restrictive and that all the postulates need not be satisfied to confidently associate a pathogen with a ...
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5 votes
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Don't understand figures in this citizen-science mosquito ID project

In the second figure – What does the color scale and color coding represent? Each color is an individual mosquito species, arranged the same from top to bottom on all plots. Here, on the ...
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  • 181
5 votes
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Why is bacterial meningitis worse than viral meningitis?

One needs to be careful making broad generalizations about meningitis. The term simply refers to inflammation of the meninges (the outer layer surrounding the brain and spinal cord). Meningitis can ...
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5 votes

Does avoiding medication that alleviates symptoms shorten the length of a cold?

The common cold as a clinical syndrome is not any particular viral infection, but a cluster of symptoms that follow a stereotypical course. It's generally associated with an initial viral infection ...
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5 votes
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How is the carrying capacity of a logistic growth model calculated?

@Remi.b is correct that you haven't given us very much information, but I think we can reconstruct what's going on. Suppose the population growth rate is written out as $$ \frac{dN}{dt} = N ( b - \...
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4 votes

Rabies transmission via barking

Between 1956 and 1977, 4 human cases of rabies virus infection were attributed to aerosolized rabies virus; Possible but very rare. https://academic.oup.com/jid/article/195/8/1144/816583
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4 votes

Is it possible to contract the plague by kissing a wild chipmunk?"

The causative agent of the plague, Yersinia pestis, can be indirectly (via a flea vector) or directly (via exposure to infectious fluid or a bite) transmitted by rodents. In the western United States ...
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4 votes
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Can endemic diseases be acute?

Endemic and chronic/acute are unrelated properties of a disease. Endemic is a description of the frequency of a disease in a population or in an area. Chronic/Acute is a description of the state or ...
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4 votes
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COVID-19 deaths by year of birth?

Data are usually binned in broad age groups partly because that's all the detail that's useful in some context, and because access to more detailed data often involves access to strongly controlled, ...
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4 votes

HPV. How do viruses persist outside the body?

bob1's answer is good, but I was already working on this one so I'll go ahead and post the parts that aren't redundant: What does it mean for a virion to lose infectiousness? To be 'infectious' a ...
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  • 3,260
4 votes
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How does the first organism infected by a disease get infected?

The key term to find information pertinent to this question is Zoonosis (link to the Wikipedia article). However, one should not generalize zoonotic origin to all the diseases affecting humans - in ...
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3 votes
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Reproduction number of a SIR model with mortality

The only answer that makes numerical sense is 1. The product of two rates beta and delta (recovery * death) doesn't mean anything in SIR. And in answer three you're doubling the rate of infection (...
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3 votes
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A study found that the hepatitis C virus can live on surfaces for six weeks. Did they end the study before the seventh week began?

The place to find this information would be the Methods section of the paper. We spotted 33 µL of plasma spiked with HCVcc on the 24-well plates. They were either immediately tested for viable ...
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3 votes
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Can a vaccine or antidote be administrated via gases or sprays?

Yes. This has been possible since the 1990's. In the US recently, the flu vaccine was recently offered as a nasal spray. There is current research being done to aerosolize several vaccines. Public ...
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