9

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

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. From Graham et al 1990 (a small [n=56] randomized trial of the use of antipyretic pain relievers in volunteers experimentally infected with rhinovirus): ...


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 ...


6

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 1996 to 2020 on the state level for antrax, brucellosis, dengue fever, leptospirosis, malaria, meningococcal disease, Q fever, rabies, etc. Weekly tables since ...


6

Gastrointestinal infections can be caused by Gram positive and negative bacteria: Gram-positive: Staphylococcus aureus Clostridium difficile, botulinum and perfringens Listeria monocytogenes Bacillus cereus Gram-negative: Salmonella enteritidis and typhi Campylobacter jejuni Shigella Escherichia coli Vibrio cholerae and parahaemolyticus Helicobacter ...


5

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 and you can isolate infectious particles early in the course of the illness, but by the time most people go to the doctor there is no active infection. Because of ...


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

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

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 ...


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

Prophylaxis is typically prior to exposure. Condoms, for example, were historically referred to as prophylactics, in that they prevent pregnancy and many STIs. The reason the pre-exposure bit is given special attention in this context is that it refers to use of drugs with substantial risk of harm. Because of their associated risk, these drugs were ...


3

I am curious, is there any known disease/infection that is very severe normally, but ends up having little to no effect on the lives of asymptomatic carriers? HIV is an obvious example, where so-called "long-term nonprogressors" successfully suppress HIV replication sufficiently that they do not develop AIDS but are unable to clear the infection entirely [1]...


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

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

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

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 ...


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