8

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, they were done. It doesn't really matter The point of the paper is that HCV is infectious long-term on surfaces when not cleaned properly, indicating there is ...


6

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, sealed exposure chambers for rapid administration of vaccines to large numbers of people, possibly in the field, for example in a tent like this figure from the ...


6

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 of all: Cockroaches do bite, and they have powerful mandibles. This is in the paper below: https://doi.org/10.1371/journal.pone.0141226 Many people think they ...


5

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 possible to make a vaccine that's attenuated enough, for example. Or a killed vaccine may not be effective. Here are some pros and cons of attenuated vaccines: ...


5

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 occur due to a number of causes, most notably viral and bacterial infections, but can also also be due to fungi, parasites, toxins, cancer, etc. There is a vast ...


5

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 left, all species are gathered on one plot, with the y-axis now labeled “Species.”   The sounds of many mosquitoes apparently have ...


4

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


4

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 in particular, Y. pestis is endemic, and ground squirrels, prairie dogs, chipmunks, and woodrats are important reservoirs (see Cecil Medicine Ch. 320). US ...


4

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 course of a disease in an individual. For example, influenza is endemic in North America: the frequency goes up and down, there's always a few people who have ...


3

It's not that people didn't want to use hemagglutinin as a target for antivirals, it's that they haven't been able to get the antivirals through the approval process yet. There are a number of experimental inhibitors (see for example Progress of small molecular inhibitors in the development of anti-influenza virus agents) but the approval and licensing ...


3

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 virus or stored at 4°C, 22°C, and 37°C for up to 6 weeks before testing. They tested their samples for (up to) 6 weeks. At the time of the 6th week they still ...


3

This is going to be an answer with less thorough sourcing, as I can't find the discussion of the common cold syndrome I recall in either Harrison's or Cecil, which is a shame, because, as far as I can remember, it was very good and really helped me get a grasp on how to approach clinical syndromes in infectious disease. The common cold as a clinical ...


3

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 health officials have an interest in this method due to it being less expensive to produce, more people can receive the vaccine in a shorter time frame, and less ...


3

The picture is too blurry for an exact determination. From what I see it might be Metcalfa pruinosa or a related species, which is an insect of the order of the Hemipteri. It's a widespread parasite of ornamental plants. Here a page about it http://ag.udel.edu/research/delphacid/species/Metcalfa.htm if true, what you posted are the nymph, and you might be ...


3

This sort of thing happened to one of my plants. When I took a closer look at the plant, it was a group of white aphids. The brown coloration of the leaves of your cherry tree was relevant because aphids can sometimes kill the entire plant that they feed off of. I did not take a picture of the plant, but I found one online: https://entnemdept.ifas.ufl.edu/...


3

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 (alpha). Looking at the other way, for R_0 it doesn't matter how people leave the Infected class, once you're either dead or recovered you no longer are ...


3

One might argue that since replication takes place in erythroblasts (Brown, Anderson, & Young, 1993), that it's not actually a respiratory infection either. Fluids are simply more hospitable to the virus and more transmissible. As for the rash, perhaps it is because the P antigen receptor that erythrovirus uses to infect erythroblasts is also ...


2

After V.cholerae gets into the human intestine it starts to multiply its numbers, and then becomes virulent after sufficiently expanding its numbers. This virulence drives the diarrhea which in part causes the bacteria to slough off into the intestinal lumen, and then into the external environment again. So in short it uses the human intestine to increase ...


2

According to wikipedia there are two different way to distinguish stage of the disease. One is from McCallan and one from the World health organisation (WHO). For the second one, on WHO website, you can find their grading card with eyes images. You can download it with also a little description. Hope it helps.


2

The question could be rephrased Can a measle virus be created anew and not via reproduction from another virus? The answer to which is "no". The falsified idea that new life forms can jump pop up out of nowhere is called spontaneous generation. Spontaneous generation do not occur. Note however that sometimes it may look like as if a new epidemic came ...


2

Only two viruses have been eliminated in the wild to date: Smallpox (humans) and Rinderpeste (cattle). As the question notes, smallpox stocks still exist. So do Rinderpeste stocks; see Identifying and Reducing Remaining Stocks of Rinderpest Virus, which is from 2015, but has no indication that the stocks were to be destroyed in the near future. The only ...


2

N. fowleri infection can occur after nasal and sinus irrigation, swimming and other exposures to contaminated water. The infectious agent in this case is the trophozoite, not the cyst. Boiling water contaminated with this amoebae kills it, preventing infection. Though it does thrive in warm water (37 C), it doesn't survive in steam (100 C). Despommier's ...


2

If the amino acid sequence of both proteins is the same, what determines whether the synthesized protein will take the disease-causing tertiary structure or the normal one? PrP-C and PrP-Sc do indeed have the same primary structure. However, they differ in secondary and tertiary structure. The protein can take more than one shape (conformation), where ...


2

First, I don't understand why you are more worried about viruses of extinct species, instead of ancient viruses of species that haven't gone extinct. Clearly the infectious potential of the latter is greater for the current species. I haven't heard a peep in published literature about the dangers of resurrecting mammoth viruses, but surely recreating (in ...


1

Are there potential biohazards in this line of research, where dormant viruses that have otherwise gone extinct (along with the extinct host) and which now may have the potential to be reactivated? There are always potential biohazards. If you dig into the unknown, you can't tell in advance what you can find. Said that I would like to point the ...


1

To make the diagnosis of syphilis, the most common tests fall in two categories : Non-specific tests like VDRL test & Rapid Plasma Reagin (RPR) test : those detect antibodies against cardiolipin, present in the treponema but also in our cells. Specific/treponemal tests like TPPA/TPHA & FTA-ABS : antibodies titers against antigen specific to T. ...


1

As @swbarnes says: Every time you expose a population of bacteria to an antibiotic, you select for organisms with resistance-granting genes. But you're asking about the situation where you're not 'sick' when you're taking them, and how it affects future infections. To understand why that's a bad thing, you need to understand a couple more things. ...


1

Every time you expose a population of bacteria to an antibiotic, you select for organisms with resistance-granting genes. Bacteria can pass plasmids full of genes back and forth. So if you get a nasty E.coli infection, do you really want one of your usual bacteria with a resistance-granting gene sitting right next to it? Let's say you are so sick you go ...


1

Since I didn't get an answer, I'll mention what I did. My goal was to understand a particular disease well enough to talk intelligently about it while focusing mostly on the statistics. So learning Epidemiology from the ground up wouldn't have been practical in the 4-5 months I had. I started with a high level patient-oriented book, C. diff in 30 Minutes. ...


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