Antivirals Relenza and Tamiflu can combat the flu virus
Since these medicines are also effective against bird flu countries such as the US have been stockpiling vast amounts against a potential pandemic.
Unfortunately it seems the virus is building up resistance – and when a real pandemic strikes we may not have any firing power left in our arsenal.
Antibiotics are also routinely abused by the agricultural sector: livestock farmers add them to feed to promote growth and prevent disease. Resistant bugs then find their way from animals and animal products to humans.
TB sidesteps science
Tuberculosis has also learnt to sidestep science. An unusually tough and slow growing microbe, TB is usually treated effectively with a combination of four drugs which are taken together for six months.
If patients are inadequately treated – either because they don’t take the prescribed treatment in the correct way or because low-quality medication is used – so-called multi-drug-resistant TB (MDR-TB) may result.
Although it’s no more contagious than ‘‘normal’’ TB this is an important health issue because treatment is longer and requires more expensive medication.
Recently South Africa has seen the emergence of extensively drug-resistant TB (XDR-TB), which is also resistant to some of the second-line medications. We’re running out of treatment options.
Of course, in South Africa TB has a sinister comrade-in-arms: the human immunodeficiency virus (HIV) which causes Aids. In this partnership an age-old bacterium and a fairly new virus have forged an unholy alliance: almost half of all patients newly diagnosed with TB are also infected with HIV.
Ready, aim, fire!
Far from racing to the rescue the pharmaceutical industry seems to be running out of answers. Some of the biggest companies – Bristol-Myers-Squibb, Eli Lilly, Roche and most recently Bayer – have abandoned research into new antibiotic drugs in favour of more lucrative pursuits.
Just seven new antibiotics have passed clinical trials since the year 2000, compared with 30 in the previous decade.
After the bravado of the previous century we now have new respect for germs – especially as it seems at the moment they’re winning the war.
The news is not all bad though. Antiretrovirals, although certainly not a cure, have revolutionised the treatment of patients with HIV/Aids, allowing them to strengthen their immune system andlive a virtually normal life.
Search for new therapies
The search for new therapies continues with help coming from unexpected sources. In 2006, after screening 250 000 natural extracts, scientists at Merck Pharmaceuticals published details of anew antibiotic gleaned from a soil sample taken in South Africa.
Called platensimycin it kills many kinds of bacteria – including MRSA – and if it passes clinical trials it will become only the third completely new class of antibiotic developed in the past four decades.
And in the forests of northern Europe researchers have found a small black mushroom that contains the first of what may be a powerful new class of antibiotics and antivirals called defensins (a type of protein that’s active against bacteria and enveloped viruses).
In some ways modern science has never been better equipped to deal with the threat of emerging disease, with better laboratory techniques such as gene sequencing allowing us to identify and diagnose illnesses much earlier.
But as Dr Joe Jarvis, a local infectious disease expert who’s researching a type of fungal meningitis afflicting patients with HIV, points out, ‘‘Preventing a future in which germs are once again widespread killers is going to take more than just inventing new magic bullets.’’
On a global level strategies have to include more rational use of antibiotics in healthcare and agriculture and, of course, improved techniques in developing new medicines.
Public health authorities should remain on high alert to contain outbreaks before they become epidemics. In the developing world, where epidemics of cholera and dysentery are spawned by war, poverty, overcrowding and poor sanitation, the provision of a clean water supply and access to primary healthcare remain of the utmost importance.