Good morning to my lovely readers

It is the best time of week again - Friday. In fact, this will be my first weekend working as a seasonal presenter for London Zoo on Sundays, so if you are around come and find me and say hi! Today's post title may sound slightly alarming, but by the end of this post, you will understand that it is not a gross over exaggeration.

Before I introduce you to the creepy crawlies a quick crash course in terminology is required: 

Anthropophilic: The Vector shows a strong preference for taking blood meals from humans. 

Zoophilic: The vector shows a strong preference for taking their blood meals from animals. 

Endophagy: A vector that takes their blood meal indoors.

Exophagy: A vector that consumes blood from their victim outdoors.

Endophily: When the vector eventually rests they remain indoors or sheltered from the external surroundings. 

Exophily: When the vector eventually rests they remain outdoors.

Allow me to introduce you to some of the vectors behind some of the worst diseases: 

What a great way to introduce you all to the world of vector-borne diseases. Now, these are not all the vectors known to us on Planet Earth but they are the ones that I selected for today  - make sure you keep an eye out for the next few to complete the series. 
As always everybody it was my greatest pleasure blogging for you. I am now of to learn more of my ZSL scripts for Sunday. 
Have an awesome weekend

Science in the City
xoxo

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Topaz

Greetings everybody

Happy Friday to all of you lovely readers. This week we are focusing on Tuberculosis.

What is Tuberculosis? 

Quick dip into history! Tuberculosis has been following humans closely throughout their history, signs of infection have been found in mummies. 

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Tuberculosis is a communicable respiratory disease (infectious) caused by a bacteria known as Mycobacterium tuberculosis. Tuberculosis manifests itself in many different species, as such not all forms are caused by that one bacteria. M. tuberculosis is the strain commonly associated with disease in humans, however, it's part of a larger group known as the Mycobacterium. tuberculosis complex. 

This complex includes the following tuberculosis-causing species: 

• Mycobacterium bovis - clue in the name. This strain mainly affects bovines but can be transmitted to mammalian hosts - like us. 
• Mycobacterium africanum - main culprit for tuberculosis transmission in West Africa. 
• Mycobacterium microti - Infects small rodents primarily
• Mycobacterium pinnipedii - Infects seals
• Mycobacterium caprae - this species is thought to be able to infect animals including humans. 

All species included in the Mycobacterium tuberculosis complex are classed as obligate pathogens. An obligate pathogen must become active inside the host for it to become infectious and ensure successful transmission from one host to the next. 

Why is tuberculosis such a worrying threat to global health? As we have seen, it is widespread amongst a variety of species. Some of the species involved in the M. tuberculosis complex are able to cross the species barrier separating animal health from human health. 

Transmission:

Size matters:

The individual bacterial agents (M. tuberculosis) involved in the transmission of this disease are very small in size. An infected individual will sneeze or cough releasing these infectious agents, their size allows for them to remain in the air for a length of time spanning from minutes to hours. Inhalation of just one M. tuberculosis will lead to the host (human or animal) becoming infected with Tuberculosis. Once again the size of this bacteria allows it to migrate from our airways to the terminal structure of our respiratory system - the alveoli. 

Perfect storm for tuberculosis transmission: 

M. tuberculosis has many mechanisms that aid its virulence found inside the bacterial genes. The bacteria that cause tuberculosis are becoming resistant to many of the drugs on the market to treat it. For more on drug resistance and why it matters click here 

Once activated M. tuberculosis triggers many symptoms that can remain mild for many months such as a cough, fever, and weight loss. This allows for the infected individual to infect others, and average 10-15 people can get infected in this way. Tuberculosis has made use of our globalized world to aid its success in transmission. Population expansion, overcrowding and the unregulated movement of people has allowed Tuberculosis to affect all four corners of the world.

Tracking the stages of this disease: 

1. M. tuberculosis bacteria is engulfed by alveolar macrophages (an immune cell) when the bacteria arrives in the lungs. Once engulfed macrophages produce chemical distress signals (chemokines and cytokines) to recruit other immune cells to the site of infection. 
2. Inside the macrophage, the bacteria begin replicating exponentially. They block the cell activating bactericidal mechanisms (processes that would lead to the extermination of the bacteria). Eventually, the bacteria cause the premature unprogrammed death of the macrophage known as necrosis. 
3. Released bacteria are then taken in by other macrophages responding to the distress signals. The process continues causing growth in necrosis tissue. 
4. It is 2-4 weeks after the initial infection when T cells (the bodies biggest and badest immune cells) are primed, prepped and ready to target the Mycobacterium 
5. These cells stop disease progression by halting bacterial replication. A combination of T lymphocytes, macrophages, and other immune cells form a wall around the site of infection (necrosis tissue and infected macrophages) 
6. The formation of this granuloma leads to the containment of the disease in 90% of infected individuals and halts the progression. 

The threat of Latent TB: 

We know the outcome for 90% of individuals affected by Tuberculosis, what about the remaining 10%? 

M. tuberculosis has one last trick up its sleeve. The bacteria retains the ability to resuscitate itself and become active all over again. 

Whilst most of the bacteria are killed in the granulomas, some manage to block the mechanisms that will lead to their destruction such as: 

• Preventing the fusion of phagosomes (these are air bubbles like vesicles filled with bacteria inside macrophages) with lysosomes (vesicles containing digestive enzymes that break down bacteria). 
• Preventing antigen presentation by MHC class 1, Class 2, and CD1 molecules. By preventing this it makes it impossible for our immune system to launch an attack because it doesn't know the target! 
• Prevents immune cells creating an inhospitable environment. 

Blocking these mechanisms allow the bacteria to enter a dormant/latent state and remain in our alveoli without detection. 

Latent Tuberculosis shows its true insidious nature during this phase.  Bacteria will continue to remain dormant waiting until our bodies immune system becomes weakened by another type of infection (e.g. HIV). Stimulated by the weakened immune system Tuberculosis is activated, allowing for the continued replication as well as disseminating throughout the body.  

Deadly dynamic duo a phrase not saved for superheroes: 

HIV and Tuberculosis are perfect bed buddies. HIV decimates the immune systems of those infected. In its absence,   M. tuberculosis ceases the opportunity and starts its path of destruction all over again. 

Check out the map below showing the prevalence of individuals infected with both TB and HIV!

Tuberculosis is a threat as a cause of multiple factors; its size, ability to disseminate around the body, route of transmission, growing antibiotic resistance, the threat of latent infections. WHO estimates that a third of the world's population may suffer from latent TB- a ticking time bomb. In the year of 2014 Tuberculosis killed 1.5 million people and was responsible for 1/3 HIV deaths. We have no idea if or when latent Tuberculosis will be activated, there was a case where a man had fallen ill to Tuberculosis that had remained dormant for 30 years (it was gained by his father). 

That was your biology fix for this weekend guys, as always I want to know what you guys thought. Did you find this interesting and if you guys want any diseases looked into any greater detail leave a comment down below!

Biobunch, 

Over and out! 

NOTIFICATION: I will be changing the name of the blog in the month of December! Please keep up to date with the change in name as I value every one of you as readers. 

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Greetings everybody

Hope you have all had an amazing week. It is time for that lovely fix of science you get from me on Friday! This week is all about looking into the world's antibiotic resistance crisis; What is it? Why should we care? And how we have reached a crisis point?. Let's launch into it then.

What is antimicrobial resistance and why should we care about it? 

WHO (World Health Organisation) defines antimicrobial resistance as the change seen in bacteria, fungi, viruses and parasites once exposed to antimicrobial drugs. Antimicrobial resistance carries the potential of plunging the world back into the dark ages of the pre-antibiotic era. What does this mean for me, you, your family and friends? Bad news. If we are unable to keep up with constantly changing microorganisms as they continue to accumulate resistance to antibiotics, deaths from the common cold and flu would rise and once simple and curable bacterial infections will lead to hospitalisation.

Let's talk money for a moment:

An independent report was published releasing the results of the impact Antimicrobial resistance would have on our future economy. I have extracted the main results from the report to read the full report click here.

They calculated the costs based on two inevitabilities in a world where antimicrobial resistance is common:

Increased mortality - deaths directly caused by the resistance of microorganisms would greatly reduce the size of the working-age population.

Increased morbidity -  these were characterised as being prolonged periods of time taken off work due to sickness. In the short-term, this would cause a temporary reduction in the workforce and in severe cases lead to a long term loss in team productivity.

It was estimated that by the year 2050 the world economy would have lost a whopping $2.1 trillion if the levels of resistance remain low. However, if this problem is not handled and resistance increases globally, the loss could peak at $124.5 trillion. If those numbers were not enough to highlight the effect this biological crisis has on the world, it is important to note that they are an underestimate. The report only considered two aspects of the economies challenges, the cost of healthcare (longer stays and an increased demand for intensive care) as well as funding to manufacture new antibiotics were not factored into the analysis.  A number not yet totalled but based on the underestimate... it's a cost best to keep as minimal as possible.

How did we get to this crisis point? 

Antimicrobial resistance is a story that stretches all the way back to the very first microorganisms. Chemical warfare has been a strategy used against rivalling microorganisms in competition for resources for centuries. Ever since the first weapon was used against another, microorganisms had to learn how to evade or neutralise those threats. Those chemicals used by one microorganism to disadvantage another or completely destroy it gave us the inspiration for many antibiotics, antivirals and antifungals on the market today. This widespread exposure of microorganisms to antimicrobials has led to accelerated development of resistance because we have placed the pressure on them to do so. In simple terms, the microbes must 'adapt' or 'perish'. Survival of the fittest. 

Since then, it has been an arms race between humanity's innovation of antimicrobials and the microorganisms ability to acquire resistance to it. If you are a betting person you would not like the 'odds' take a look at the image below showing the number of antibiotics released over the years. 

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In the picture below, a scientist is holding up two Petrii dishes. If you observe them closely you will notice that on each petri dish there are small white circles. Each one of those is a small paper disc dipped in a different antibiotic, the aim is to grow a certain type of bacterium on the plate and see how effective each antibiotic is at killing the bacteria.  The first petri dish shows you that the anitbiotics are effective at killing the bacterium (observe the zone surrounding each circle that is completly clear of any bacteria). Compare this to the second petri dish, the antibiotics are largely ineffective in killing of the bacteria - sadly this is the situation we are heading towards. 

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The overuse and misuse of current antibiotics:

Lack of new innovative drugs is not the only factor playing into the accelerated growth of antimicrobial-resistant microorganisms. Some of the blame falls on individuals within the public. Every time a doctor has prescribed you a course of antibiotics to help you with some form of bacterial infection, you begin taking it religiously out of desperation to feel better. As the symptoms begin to subside you start missing a dosage or two or perhaps, you skip the last day completely. This could leave the last few remaining bacterium behind and these guys are placed under a selective pressure 'adapt resistance' or 'die in the next dosage'. If you were a bacterium which would you pick? Below is an image showing just a few ways become resistant to antibiotics. 

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Antibiotic misuse relates to the scenario where a doctor gives you antibiotics for some form of infection that is so mild, that the body should be left to fight it on its own. For resistance to happen microorganisms must be in contact with some form of an antibiotic. In the case of giving antibiotics for a mild bacterial infection, you  may think what is the real harm. If it becomes resistant then the body will overcome it anyway, right? You would be correct. There would be no worry if the mild infecting bacterium kept the code of resistance to itself. The nasty thing about bacteria is that they like to share these codes for resistance with each other. Suddenly a more severely infecting bacterium has the code to resistance to multiple different drugs that it itself has never come in contact with. 

These are reasons that many have heard before and you will hear more and more as this issue becomes more and more public. I went in search for the lesser known ways of how we got to where we are today. 

The real monster lurking in our sewers:

Antibacterial products discarded into the sewage from our own communities and even hospitals   all collect to form the perfect reservoir for antibiotic resistance to cultivate. This hotspot of antibiotics, pollutants, detergents, and disinfectants creates such a hostile living environment that it truly drives the incentive of each bacterium to develop resistance to multiple chemicals designed to kill them. 

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There are many ways that resistant microorganisms can be transferred onto us. Take a look at the image below to check out a few more. 

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21st Century Problem in need of a Solution... 

We could panic after this post. You would be well within your right but as I have been told by one of my students I am incredibly optimistic. It will be a tough battle to fight, one of the greatest in our history perhaps due to it global impact on both our health as well as our economies. Microorganisms have had to adapt under increased exposure to antimicrobials. I believe that 'Necessity is the mother of invention' as such in the face of an enemy we will overcome it. We are left with two choices 'Adapt' or 'Die'. Which do you choose? 

Biobunch

Over and Out 

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Unknown

Greetings everyone,

Today marks a marvellous day because it is the second post of the new series 'Biology Behind' every other week we will take a theory, a disease, or a natural phenomenon and look at how biology drives it into being! so without further a dew we give to you today's post...

In the UK there are approximately 700,000 people out of a population of 61 million who are diagnosed with dementia, and it was found that more than 70 diseases/disorders are associated with this condition.

 

Post highlight: Did you know that Dementia is actually not a disease in itself such as Alzheimer's, it is in fact diseases that can eventually lead to dementia!

Like most conditions, dementia is pretty hard to define however we found one that seemed to be widely accepted. Dementia is thought to be a progressive deterioration in cognitive function, more than what is expected to be from normal aging and is due to damage or disease. 

The symptoms that are associated with dementia are split into two different categories

1. Cognitive symptoms: impairments in language, praxis, judgement, visuospatial function and related mental activities.
2.  Non-cognitive symptoms: disturbance in behaviour, mood, belief and experience (hallucinations).

Now that we have outlined the symptoms that come with dementia, it is important to note that although dementia is a development from other diseases there are 'types' of dementia.

So, we know that dementia is not a disease but caused by a disease, we know that when talking about the symptoms of dementia that we can break it down into two separate categories, no we move onto what factors or diseases can lead to dementia. 

Alzheimer's disease: unsurprisingly, this is the most common cause of dementia. The chemistry and structure of the brain in an Alzheimer's patient changes and their brain cells begin to die prematurely.

Stroke (vascular problems): this is as a cause with problems of the blood vessels. All blood vessels leading to the brain are extremely important as the brain needs a rich and continuous supply of oxygen and when interrupted brain cells begin to die causing vascular dementia.

Dementia with Lewy bodies: this is where tiny spherical clusters of protein build up within the nerve cell, thereby affecting chemical signalling between one nerve cell and the next. It affects the patients memory, concentration and ability to speak, it is also often mistaken for Parkinson's Disease.

Frontotemporal dementia: this dementia includes Picks disease (this is considered to be a progressive form of dementia involving localised atrophy of the brain.) In this form the front part of the brain is damaged which in the short term affects behaviour and personality and then later on the memory starts to become affected.

Other diseases that can lead to dementia are: progressive supra nuclear palsy; Korsakoffs syndrome; Binswangers disease; HIV and AID's and Creutzfeldt-Jakob disease; common Parkinson's disease; Huntington's disease; Motor Neurone disease and Multiple Sclerosis. People with high blood glucose levels have a higher risk of dementia even without diabetes.

This brings us to the end of our post! we hope that you enjoyed this post and make sure that you visit our blog again on Wednesday for the animal of the week wondering what it is well you are going to have to come back and see! And we will leave you with this fact it has been proven that being by lingual or having the ability to speak  another language other than your own could help in preventing dementia.Well in that case...

@Biobunch.
Cambio y fuera!

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