As regularly happens in the middle of a cricketing World Cup, conversation turns to which players would comprise the best ever cricket team. I am no exception, although being an Infectious Diseases Physician, here’s my variation on the theme.
I’ve tried to work out which bacteria, viruses, fungi or parasites would make a fearsome cricketing Test XI that could pulverize any immune system it encountered. Well, here’s my team:
The Test XI
1. Tuberculosis (opener)
2. Strongyloides (opener)
3. Rabies (premier batsman)
4. Avian influenza (premier batsman)
5. Multiresistant MRSA (batsman)
6. Epstein-Barr virus (all-rounder)
7. HIV (wicketkeeper and captain)
8. Dengue (spinner)
9. Campylobacter (spinner)
10. Ebola (fast bowler)
11. Group A streptococcus (fast bowler)
The Openers (Numbers 1 and 2)
Good opening Test batsmen need to negotiate the new ball; therefore, they need to be watchful early on with a solid defence. Once established in the middle and having seen off the new ball, they can consolidate and become more aggressive.
My choice: Tuberculosis and Strongyloides
Tuberculosis (TB) is a bacterial infection that everyone knows. Although less of a celebrity, Strongyloides is a parasitic infection found all over the world. TB and strongyloides are ideal infections to open the innings because they both share an ability known as latency. When they initially infect a person, the immune system can wall them off and stop them making someone sick. The problem here though is that the organisms aren’t dead. They are in a dormant state, waiting for the immune system (our body’s “new ball”) to weaken so it can reactivate. So it happens that when our immune system wears down with age, illness or through powerful medications, then these infections can come alive with some gusto, rapidly spreading all over the body and making people desperately ill - the ideal opening batsmen.
The Premier Batsmen
(Numbers 3 and 4)
These are the star batsmen of the team. Even though they prefer the openers to see off the new ball, these players are of such class that they can plunder any bowling attack at any stage of the innings.
My choice: Rabies and Avian Influenza (H5N1, bird flu)
Transmitted to humans from infected animals, the rabies virus causes a severe brain infection known as encephalitis. In people with rabies who didn’t get immunized before or after being exposed, this infection is nearly universally fatal - an infection almost without hope.
Avian influenza has one flaw - it hasn’t made the evolutionary jump to efficiently allow humans to infect other humans. But it kills around 60% of people that it infects - a staggering death rate for influenza or any infection in general! It is worth remembering that swine flu (H1N1) has a death rate many thousands of times less than avian influenza - and look how much trouble swine flu caused.
Number 5 batsman
Although an important position, this batsman doesn’t have the skill to negotiate the new ball early in his innings. Likewise he may not have the technical brilliance of his predecessors at 3 or 4; however, he’ll still be a classy player.
My choice: MRSA (multiresistant)
Staphylococcus aureus is a common bacterium found in our skin and noses. Multiresistant methicillin-resistant Staphylococcus aureus (or MRSA) is a more resistant form found mainly in hospitals. While it can quietly live on our skin without causing problems, MRSA can cause serious problems if it enters a wound or the bloodstream. Unfortunately, such opportunities are rife in the hospital environment in which it is found. When it enters the bloodstream, it can kill up to 30% of its victims, infecting heart valves, joints, bones and brains on the way.
Number 6 (All-rounder)
Although the term “all-rounder” is loosely used these days, the true all-rounder is a player who excels in all facets of the game.
My choice: Epstein-Barr virus (EBV)
In young people, EBV can cause glandular fever, also known as infectious mononucleosis or “mono”. In addition, like the “opening batsmen” (TB and strongyloides), it lies latent in our bodies and can relapse later in life. Finally, EBV can cause different cancers such as lymphoma and nasopharyngeal carcinoma. With glandular fever, latent infection and cancer in its repertoire, EBV is a true all-rounder.
Wicketkeeper/Captain (Number 7)
Both wicketkeepers and captains have the difficult task of motivating their charges and bringing the best out of them. In addition, a wicketkeeper is expected to be able to bat competently.
My choice: HIV
HIV works by attacking the immune system, depleting a subset of cells called CD4 cells. By doing so, it allows infectious agents that usually wouldn’t make people sick, to generate life-threatening illness. Organisms such as Pneumocystis, Cryptococcus and Toxoplasma transform from innocent bystanders into harbingers of disease-ridden doom. In other words, HIV lets these normally harmless organisms realise their deadly potential - like any good captain or wicketkeeper would do. In addition, HIV has its own artillery and by itself can induce a variety of ailments such as dementia, meningitis and blood abnormalities.
The Spinners (Numbers 8 and 9)
A good spinner uses drift and slight variations in action to deceive batsmen into a fatal shot. They are the illusionists of the game.
My choices: Dengue and Campylobacter
Both these organisms can bamboozle the immune system. When someone gets a dengue infection for the second time, the immune system mounts its response to the original infection. Not only is this ineffective in fighting the new dengue virus but the immune response can be so strong that it can harm the individual.
The Campylobacter bacterium causes diarrhoea which eventually settles; however, some parts of Campylobacter are structurally similar to the human nervous system. This similarity can confuse our immune system into attacking our own nervous system. This leads to a type of life-threatening paralysis called Guillain-Barré syndrome, usually seen a few weeks after the Campylobacter infection - a lethal form of deception.
The Fast Bowlers
(Numbers 10 and 11)
These are athletes who rely on rage and frightening speed to intimidate and occasionally injure opposing batsmen. They are aggression personified.
My choices: Ebola virus and Group A Streptococcus
The word “Ebola” is enough to strike fear into most people. This African virus can cause epidemics that rapidly infect whole villages and spread from person to person. Death is excruciating with internal organs often haemorrhaging and turning to mush. Death is also common with 50-90% of sick people dying.
Group A Streptococcus (GAS) is a common skin bacterium; however, some strains can produce toxins that can rapidly induce multi-organ failure and kill even the healthiest individuals. Another vicious form of GAS is necrotising fasciitis where an innocuous skin infection turns into a relentless consumption of flesh which eats its way down deep into the guts or bones. Antibiotics are useless - extensive repeated surgery is the only cure.
So there you have it - eleven deadly bugs possessing different qualities to cause medical mayhem. While my choices may be contentious, you’d have to agree that it is a group of infections that would challenge any immune system.
( Sanjaya Senanayake is an Associate Professor of Medicine at the Australian National University and a Consultant Physician in
Infectious Diseases) |
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