Questions tagged [infection]

An infection is caused by the invasion of by pathogenic organisms (bacteria, viruses or worms) into a host. These pathogenic organisms live and multiply in its host and cause diseases by this.

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96
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3answers
15k views

What's the evidence against SARS-CoV-2 being engineered by humans?

A couple of colleagues suggested in a discussion that the virus that causes COVID-19 appears to be made by humans, since nature could not have produced such an efficient virus — that spreads so fast ...
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2answers
11k views

What is the benefit of fever during infections?

When people get sick, they often develop a fever. What is the effect of an increased body temperature on viruses and bacteria in the body? Is it beneficial to the infected body? Importantly, often ...
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2answers
45k views

Why don't we develop immunity against common cold?

We all suffer from common cold, and that, frequently. Why have we not developed immunity against it till now? By immunity I mean immunity as a species.
36
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7answers
5k views

Has there even been a clinical study where healthy volunteers consented to be infected with a pathogen?

I am curious if there has ever been a (modern) clinical study where a healthy volunteer was purposefully infected with a pathogen in order to test the effectiveness of a therapeutic or preventative ...
28
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3answers
3k views

Why was disease transfer to the Americas one-way?

It is well known that the European colonists brought many infectious diseases to the Americas, and that these had a deadly effect on the native populations, because they had no immunity to them. Were ...
26
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2answers
8k views

Is the Common Cold an Immune Overreaction?

It's my understanding that the majority of symptoms associated with the common cold (runny nose, inflamed sinus, slight fever) are essentially the result of the immune system's response. I've never ...
26
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3answers
6k views

Did the Zika virus mutate?

The Zika virus was already present and known to the world (mostly in Southeast Asia) before the current outbreak. Why has the virus caused such an extreme outbreak? Has it mutated from its ...
18
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1answer
4k views

Do we actually get more sick (flu/cold) during winter?

The word flu derives from the Italian phrase "influenza de freddo" meaning "influence of the cold". Indeed it is that time of the year when my colleagues seem to have the flu/cold more often than not....
12
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2answers
2k views

How long does the Ebola virus remain infectious on contaminated items or surfaces?

I'm sure there will be variation depending on what the contaminated item or surface is made of - linens, I could imagine, would remain dangerous for longer than a door-knob. But if the items are not ...
11
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4answers
299 views

Is there a period after you have had a cold when you cannot get a cold again?

I always assumed colds ran on a 'no tagbacks' principle: once it's out of your system, it takes a while before you can get a cold again. Is there any truth to this, or can rhinoviruses hit you at any ...
10
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4answers
30k views

Does a microwave oven disinfect food?

Imagine I am preparing food -- just about to put it into a microwave oven -- and some of it falls on the floor. Assuming it got some bacteria or other organisms (viruses?) on it, will the microwave ...
10
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1answer
328 views

Septic Shock: I'll kill myself before you kill me

Most of the deaths caused by extracellular bacteria don't actually result directly form their action. Rather, it results from an overreaction of the immune system to antigens such as LPS and LTA (...
10
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4answers
1k views

How can insects survive without an adaptive immune system?

How can insects survive in a world full of pathogens that are able to defeat the innate immune system?
10
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1answer
205 views

What is the difference between influenza A and B viruses that causes their distinct seasonal patterns?

I recently learned from an answer at health.SE* that influenza B tends to occur later in the season compared to influenza A. According to the graph in that answer, during this year’s flu season the ...
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2answers
2k views

To what extent is Ebola airborne? (aerosols)

Recently, CIDRAP at the University of Minnesota announced that Ebola may be more transmissible through aerosols than previously thought. I lack the familiarity with the field to critically evaluate ...
8
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4answers
406 views

Organisms as potential Bio-Weapons?

Question: Given that with genetic engineering we can customize organisms as bio-weapons. Which species have the most worrying potential to be weaponized for mass destruction? Background: ...
8
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1answer
224 views

Is Zika suspected of causing birth defects only if contracted during pregnancy?

There seems to be growing evidence that a recently spreading strain of Zika virus is in fact linked to microencephaly and other birth defects in newborns (see here, here, and here for examples). I ...
7
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1answer
24k views

How the conjunctivitis virus spread just by seeing a person's eye who is infected

Conjunctivitis or 'pink eye'. I have a few questions on conjunctivitis. When I was suffering from conjunctivitis, my doctor advised me to wear sunglasses so that no one else gets infected. I wonder ...
6
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1answer
104 views

What (if anything) about tuberculosis makes producing a highly effective vaccine difficult?

What about tuberculosis makes it difficult to produce a safe vaccine that is effective at producing an immunogenic response in >99% of individuals against all strains of the bacteria? I am aware of ...
5
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5answers
501 views

Can an influenza virus carry other infectors with it?

This idea came to my mind when thinking about how many people become ill in many locations with similar symptoms (fever and rough cough) from Influenza. There are of course different types of ...
5
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2answers
21k views

Does drinking alcohol having UTI may help to kill the bacteria?

It's well known that ethyl alcohol kills bacteria. And amount of alcohol in urine may be detected by EtG tests (as long as 3-4 days after intake). Does drinking alcohol in reasonable amount by ...
5
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1answer
191 views

Why are victims of Covid19 being wrapped in plastic?

Several articles describe the unique ways Covid-19 patients are being buried. For example, in this Reuters article about Israel: These included decontaminating and hermetically wrapping bodies in ...
5
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2answers
158 views

Reproduction number of a SIR model with mortality

We know that reproduction number $\mathcal{R}_0$ is $\frac{\alpha}{\beta}$ for the following system, such that if $\mathcal{R}_0>1$, there is an epidemic in the population. Now, assume the system ...
5
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1answer
1k views

Why is the upper respiratory tract so vulnerable to infections?

Wikipedia has the following statement on its Upper respiratory tract infection page: In United States URIs are the most common infectious illness in the general population. What is it about the ...
4
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2answers
119 views

Do organisms use detergents to fight off viruses?

Common advice against contracting bacteria or viruses is to wash your hands because soap dissolves the viruses' shell. Does any organism exploit this effect to protect against infection, e.g. by ...
4
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1answer
108 views

Why are the bacteria that cause hospital-acquired infections resistant to many antibiotics?

Why are the bacteria that cause hospital-acquired infections resistant to many antibiotics, and why don't hospital acquired infections exist elsewhere ? The infections that are caused in hospitals ...
4
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1answer
7k views

How does a virus take control over the host cell?

When the virus integrates its DNA with the hosts and enters the lytic pathway, do the viral proteins that produced destroy the cells DNA? Do they deactivate it? Also does the cell function in the same ...
4
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2answers
693 views

How does your body know when it is infected so it can invoke a fever?

How does your body know when it is infected with a virus or bacteria so it can invoke a fever or ramp up the immune system?
3
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3answers
2k views

If ants have an antibiotic gland, how can they spread hospital infections?

Wikipedia describes how antibiotics are produced in ants: "Metapleural glands ... are responsible for the production of an antibiotic fluid that then collects in a reservoir ... also referred ...
3
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1answer
1k views

Why does a Urinary Tract Infection cause a strong, persistent urge to urinate?

There are plenty of articles on the fact the a urinary tract infection (UTI) causes frequent and urgent urination. For example; on this National Institutes of Health webpage. My question is: Why ...
3
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2answers
379 views

TB disease - treatment and infection

Background: I'm currently performing research in mathematical biology, specifically on the treatment dynamics of HIV and TB co-infection. Question: Can a person infected with TB disease, who are ...
3
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2answers
295 views

what will be the effect of cockroach bite?

I know the cockroaches are creepy for humans. But I want to know why humans are afraid of cockroaches and what will be the effect of there bite on my body. Can I touch them or if they walk over my ...
3
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3answers
6k views

Why should benzalkonium chloride (an antifungal agent) be used during your laundry machine's “rinse” cycle, not its “wash” cycle?

I'll first provide lots of background information. My actual question is at the very end. Background The spread of athlete's foot Athlete's foot is a fungal infection which is mildly contagious. ...
3
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1answer
110 views

When infected with malaria, how many parasites are within a human host?

When infected with malaria, how many P. falciparum cells are within a human host? And how does this compare with the average infection parasitemia of A. gambiae? I can't seem to find a reliable source ...
3
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2answers
159 views

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., ...
3
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1answer
486 views

Is the Basic Reproduction Number in epidemiology dependent on population size?

I am assuming that the basic reproduction number $R_0$ of a disease depends on the population size (or the number of susceptible individuals). When $R_0$ is reported it seems to be without such ...
3
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2answers
414 views

Can suppression of the immune system help cure chronic diseases?

I am not a biologist, but recently while reading an article on Scholarpedia about self-organization I encountered a fascinating biological observation concerning immune response to infections. To ...
3
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1answer
178 views

Is it possible to get infected with HIV from old blood?

Let's say that someone uses a needle which has some old blood infected with HIV. In this case, is it possible for them to get infected with HIV?
3
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3answers
1k views

Why do 6-8% of diphtheria patients do not develop natural immunity after being affected?

I am thinking of why some patients do not have natural immunity after exposure to the A-B toxin of diphthria. I think the A-B exotoxin is the key factor causing this disease and should trigger memory ...
3
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1answer
51 views

Pox virus infection process

How does Pox virus duplicate it's genome? Does it bring DNA polymerase or RNA polymerase into the host cell?
3
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1answer
442 views

How can a pathogenic bacterium be avirulent?

Streptococcus pneumoniae R6 is a pathogenic bacterial strain but it is avirulent. How can a pathogen be avirulent. What does it mean if a pathogenic bacterium is avirulent?
3
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1answer
635 views

Does long term use of antibiotics in humans actually lead to a greater risk of infection?

I've read about the overuse of antibiotics leading to antibiotic resistant strains of bacteria, so generally does long term use of antibiotics breed these strains in the bodies of antibiotic users and ...
3
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1answer
178 views

How does the adaptive immune system store information?

I am quite curious about this: Where and how is knowledge that the adaptive immune system accumulates stored? What is the "memory size limit" of this storage method if there is any? Why cant this ...
3
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1answer
292 views

Could the growth rates of Vibrio vulnificus be affected by an oil spill?

I live on the Gulf Coast, and Vibrio vulnificus has recently made the news due to an increase in the number of reported infections. Naturally, it has people around here worried. I live in an area that ...
3
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1answer
2k views

Elevated position effect on recovery times from upper respiratory infections at rest?

In nursing school, they advice for people with upper respiratory infections to be in a slightly elevated position at the head region when sleeping. My intuition of the reason is that the lymphatic ...
3
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0answers
76 views

How can Haemophilus influenzae survive and grow alone in the human body?

Haemophilus influenzae gets its name from the fact, that it requires nutrients from blood in order to grow. More specifically, I see it mentioned that in vitro they often exhibit the pheomenon that ...
3
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0answers
59 views

Can immune cells be recruited to an area of inflammation, and later go on to a second?

With regards to innate or adaptive immune cells... can naive/immature cells such as neutrophils, monocytes, macrophage/dendritic cells or adaptive T-cells be recruited to an area of inflammation, for ...
3
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0answers
164 views

Whole gene sequence analysis to determine source infection [closed]

Is it possible to use whole gene sequence analysis to distinguish between a common source infection and a person-person disease transmission?
3
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0answers
41 views

Wolbachia - cytoplasmic incompatibility

I read that cytoplasmic incompatibility in Wolbachia occurs when wolbachia-infected male insects mate with wolbachia-free female insects and produce non-viable offspring. By contrast, wolbachia-...
2
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2answers
155 views

Why do people use anti-inflammatory drugs?

Why people should take anti-inflammatory drugs, when inflammation is a physiological way to defend our organism?