When introductions go bad

My first sighting of the red squirrel was in Camperdown Park in Dundee in 2003. I remember that scene vividly. I had since tried desperately to see this elusive animal again but to no avail, save a brief sighting, again in Camperdown Park, in Autumn 2010. This is because although red squirrel, which is native to UK and  is  protected in Europe, is outnumbered by its foreign relative, the grey squirrel that was introduced to the UK from America. Grey squirrel has several competitive advantages including its resistance to squirrel parapox virus which is fatal to the red (grey squirrels are vectors), increased fecundity, and greater ability to digest a wider variety of food. In fact, the future of the red squirrel in the British Isles is rather precarious. The Forestry Commission estimates that there there are only 140,000 red squirrels compared to over 2.5 million greys.

Recently during a holiday near Lake Geneva, Switzerland, I encountered 2 red squirrels and 1 black squirrel  (resembled the red squirrel with respect to the ear tufts, but with a black/grey rather than red coat). You can see a video here in Youtube:  http://www.youtube.com/watch?v=g4SqcK9CME8

There is a lot of debate on how the introduction of alien species can affect the native species and tilt ecosystems, but studies indicate that certain ecosytems could be more vulnerable that others. As early as 1958, Charles Elton claimed that ecosystems with higher species diversity were less subject to invasive species as there are  fewer available niches. A recent paper by Eisenhauer et al shows that species diversity could stabilise communities during invasions. It appears as if biodiversity of ecosystems provides increased resilience against onslaughts including that by foreign invaders. Caution should be exercised when foreign species are introduced. In light of these observations, a  proposed law in Brazil is of importance. A recent correspondence in Nature by Vitule et al (May 2012) warns of the repecussions of a new law that, if approved, would allow farming of foreign fish species in cages. The fishes that are being considered for introduction are tilapia and carp. The authors warn that the indigenious aquatic ecosystem would be disrupted if these  introduced species were to escape and would jeopardise the aquatic biodiversity which is already fragile due to  human activities such as pollution and construction.

References:
Vitule JR (2012). Ecology: Preserve Brazil's aquatic biodiversity. Nature, 485 (7398) PMID: 22596145
Eisenhauer N, Scheu S, & Jousset A (2012). Bacterial diversity stabilizes community productivity. PloS one, 7 (3) PMID: 22470577
http://www.europeansquirrelinitiative.org/the_threat.html


Red Squirrel image source: Sarah Stephen

Painting with the same brush: herbal medicine

Britons spend 4.5 billion GBP (60 billion GBP worldwide) on alternative medicine treatments, with the 150,000 alternative therapists in the UK being visited by one in five UK residents.

The above is a fact gleaned from the Economist, one of my favourite magazines which occupy a lofty position along with National Geographic, Nature, PNAS, and Science. They have, however, a rather interesting (and persistent) stance on alternative medicine: ‘Virtually all alternative medicine is bunk; but the placebo effect is rather interesting’.

Alternative medicine is a comprehensive term referring to a mish mash of traditional, indigenous, and unconventional medical practices such as acupuncture, aromatherapy, chiropractic, homeopathy, reflexology, reiki, and many more. Indeed, some of the practices does merit healthy scepticism. I cannot deny that there are quacks in alternative medicine and that many (if not all) do exaggerate the supposed benefits of the drugs/treatments. But then, all conventional medicine cannot be discarded as dangerous chemicals and expensive treatments which expand the bank accounts of GPs and pharmas. Neither can all unconventional medicine be discarded as outdated, bizarre, and toxic. It is up to the patient to make a well-informed decision. But it is highly debatable whether herbal medicine/ethnopharmacology should be painted with the same brush.

The Economist grudgingly admits that a few treatment (‘mostly herbs containing active drug molecules, do have proven benefits’). Yet, their conclusion is that it is none other than the placebo effect, i.e. ‘the strange and inadequately explained tendency of certain medical conditions to respond to anything the patient thinks is directed at treating them, even when the treatment in question could not possibly have a direct effect on the disease’. In other words, a treatment, per se, would have no effect on the condition, but the belief in its efficacy works wonders, resulting in somatic changes. Apparently, this works most effectively with psychological problems (or anything pertaining to emotions) such as depression and pain. And ‘the alternative-medicine industry plainly excels as a placebo delivery service’. The article concludes by pointing out that practitioners of conventional medicine could be less clinically detached, and more caring and attentive to the patient.

The fact is that many (not ‘few’ as claimed by the Economist) of the conventional medicines are/were derived from herbal products (Analgesics such as Aspirin from Salix, Morphine, Codeine from Papaver somniferum; Digitalin from Digitalis purpurea; Malarial drugs such as Quinine from Cinchona and Artemsinin from Artemisia annua; Reserpine from Rauwolfia serpentina; Physostigmine from Physostigma venenosum; Tubocurarine from Chondrodendron; for cancer-Vinblastine/Vincristine from Catharanthus roseus/Vinca rosea, Etoposide from Podophyllum, Paclitaxel/Docetaxel/Taxol from Taxus, Combretastatins from Combretum caffrum….. to state a few).

Many such herbal remedies have been used since time immemorial in indigenous medicines around the world. Indeed, adopting these remedies directly may pose the concerns of drug toxicology, side effects, and general effectiveness. It is equally likely that their effects may not be significant, whilst studies by pharmas (on their chemically synthesised products) might show significant results (one must not overlook the importance of sample size in getting significant results!). Furthermore, pharmas have more than sufficient capital to invest in large-scale research to test drug efficacy and toxicology prior to clinical trials. An ethnopharmacological research team lacks such resources.

Ma et al (2005) identified plant-derived medicines as becoming the next major commercial development in biotechnology. Their abstract states: ‘The advantages they offer in terms of production scale and economy, product safety, ease of storage and distribution cannot be matched by any current commercial system; they also provide the most promising opportunity to supply low-cost drugs and vaccines to the developing world’. Perhaps one emphatic evidence is in the form of the numerous clinical trials being conducted in the US on plant-derived medicines .

Conventional drugs too have side effects which we often overlook- after all, we blindly trust our GPs, believing that any medicine prescribed is fool-proof (reading the medicine's own fine print should throw at least some light on this). Extracting the active ingredients from a herb (thanks to coming across its usage in some traditional medicine), commercialising it and reaping the benefits, only to criticise the practice which had already identified its benefits centuries ago- a dog biting the hand that feeds?

What next? Chucking out vegetables?

References :
Ma, J. K-C., Chikwamba, R., Sparrow, P., Fischer, R., Mahoney, R., and R.M. Twyman (2005). Plant-derived pharmaceuticals – the road forward. Trends in Plant Science, Vol. 10, Issue 12, pp. 580-585.

Alternative medicine: Trust me, I've got a licence

Regulating alternative medicine: But does it work?

Medicine: There is no alternative





Image: Gingko biloba (© Creativ Studio Heinemann/Westend61/Corbis)

Super bugs and Super sleuths : E.coli outbreak in Europe

Earlier this week on Monday came reports from Germany that 6 people who consumed raw vegetables were killed and hundreds rendered ill . Initial investigations pointed towards consumptions of raw cucumber, lettuce and tomatoes. The fatalities were attributed to hemolytic-uremic syndrome, or HUS, from E. Coli. Since then, more people have died and the infection has spread to different parts of Europe . Cases have been reported from Sweden, Austria, Denmark, France, Netherlands, Norway, Spain, Switzerland and the United Kingdom. At the initial stages opinions about whether the strain was new differed between scientists. Scientists at the Beijing Genomic Institute called it a new "super-toxic" E. coli strain whilst the U.S. Centers for Disease Control and Prevention said that it was a known strain.

Today the WHO announced that the German strain was novel and that it had never been isolated before in humans. With the death toll having risen to 18, whilst over 1000 people remain ill, German scientists are desperately trying to sequence the bacterial genome. The news from WHO also indicates that the strain had never been found in any animals which signifies that it could have come directly from the environment into humans. The scientific community is awaiting with bated breath for the results from sequencing of the genome of this deadly strain of bacteria . The sequence of this strain of E.coli might explain the differential infection pattern observed- the bacteria is mostly infecting adults, and generally women.

Emergence of super-bugs are of grave concern. In April, the Lancet reported bacteria carrying a gene that confers resistance to a major class of antibiotics identified in samples of drinking water and sewage effluents from New Delhi. This gene blaNDM-1 encodes the enzyme New Delhi metallo-β-lactamase 1 (NDM-1). Bacteria can pass genes easily through plasmids. The enzyme blocks the activity of a range of antibiotics. NDM-1-positive strains of both species have previously been found in hospitals in India and Pakistan and have already been seen in the United Kingdom and elsewhere in patients, some of whom had previously been in hospitals in the Indian subcontinent.

The problem with virulent bacteria as with most infectious agents is that it is hard to be confined. As of now, the source of the German E.coli strain has not been pin pointed. With bacterial outbreaks such as this there is nothing called a ‘local problem’ but a ‘global problem’ and combating it requires a concerted effort where the blame game doesn’t help much.

References:

German E. coli outbreak caused by previously unknown strain (Nature, June 2nd, 2011)

World health officials scramble to stem deadly E. coli outbreak (CNN, June 2nd, 2011)

EHEC outbreak: Rare strain of E. coli unknown in previous outbreaks (WHO, June 2nd, 2011)

Kumarasamy KK, Toleman MA, Walsh TR, Bagaria J, Butt F, Balakrishnan R, Chaudhary U, Doumith M, Giske CG, Irfan S, Krishnan P, Kumar AV, Maharjan S, Mushtaq S, Noorie T, Paterson DL, Pearson A, Perry C, Pike R, Rao B, Ray U, Sarma JB, Sharma M, Sheridan E, Thirunarayan MA, Turton J, Upadhyay S, Warner M, Welfare W, Livermore DM, & Woodford N (2010). Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. The Lancet infectious diseases, 10 (9), 597-602 PMID: 20705517

Poirel L, Hombrouck-Alet C, Freneaux C, Bernabeu S, & Nordmann P (2010). Global spread of New Delhi metallo-β-lactamase 1. The Lancet infectious diseases, 10 (12) PMID: 21109172