The Pharmaceutical Journal Vol 267 No 7174 p726
17 November 2001

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Health on the farm [more]
Persistent resistance [more]
Music and emotion [more]

Health on the farm

Some people think of farming environments as places where people are extremely lucky if they do not develop hay fever, assorted animal infections and a range of allergies. After all, an unusually high incidence of respiratory complaints might be expected in humans who spend much of their time in an atmosphere where damp alternates with dry dust derived from manures, pesticides and germ-laden soil, so that they breathe in the resultant moulds, fungi, bacteria and synthetic chemicals. However, this is apparently far from the actual situation.

An article by a group of allergologists in Austria and other countries in the region in The Lancet for 6 October shows, on the contrary, that long-term exposure to farm atmosphere from an early age induces a powerful protective effect against the development of asthma, hay fever and atopic sensitisation. We should pity the poor city dweller for whom these benefits of the open-air life are not available. Rural areas in Austria, Germany and Switzerland were selected for the survey, in which parents of about 3,000 children in school grades 1 to 6 answered a questionnaire on respiratory and allergic diseases. Children of parents who reported at least one wheezing attack in a child during the past 12 months were judged to be asthmatic. Atopic dermatitis and hay fever were judged on a medical diagnosis. Assessments were made of a child's exposure to stables and farm and pet animals, of the duration of breast-feeding, and consumption of home-grown food and farm milk.

Complete data were available for 310 farmers' children of mean age 9.42 years and 493 children from non-farming families. The prevalence of symptoms of hay fever and asthma was significantly lower in farm children than in others. The lowest frequency was in children exposed to a farm environment in their first year of life. Exposure from the first to the fifth year produced most significant results. Raw farm milk, richer in lipopolysaccharide than pasteurised milk, was assumed to be a protective factor. Moreover, regular contact with farm animals, even in children who did not grow up on a farm from infancy, apparently protected against allergies.

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Persistent resistance

I remember many years ago attending conferences where the growing problem of resistance to antibiotics and other antibacterial agents was discussed and was pronounced serious and demanding urgent solution. Such practices as the use of suboptimal doses of antibiotics in humans, their inappropriate administration, as for the common cold, and the widespread use of antibiotics to speed the rearing of cattle, were roundly condemned, although there were mutterings from the manufacturers concerned. Today, it appears, we are facing the same problem, and the health hazard from inappropriate antimicrobial treatment has grown.

Three studies and an editorial published in The New England Journal of Medicine for 18 October emphasise the grave hazard we face, and the wide extent of misuse of antibacterials in animal feeds throughout the world. In Europe and North America these have now been used for nearly half a century, the drugs involved being identical to or closely related to those employed in human therapy, including penicillins, tetracyclines, cephalosporins, fluoroquinolones, avomycin and virginiamycin. There is controversy over the amounts concentrated in animal feeding, but it is estimated that 50 per cent of all antimicrobials produced in the United States are consumed for non-therapeutic purposes, mainly for growth promotion.

There is a movement to ban subtherapeutic uses in animals since it has been discovered that 20 per cent of samples of minced meat obtained from supermarkets were contaminated with salmonella, most isolates being resistant to at least one antibiotic. Another pathogen, campylobacter, is frequently isolated from poultry from the same source. At least 17 per cent of chickens in the market in four states in the US carried enterococcal strains resistant to quinopristin-dalfopristin, this being attributed to the widespread use of virginiamycin in chicken feed. Chickens and pigs carried glycopeptide-resistant and streptogramin-resistant strains of enterococci that could colonise the intestinal tract of healthy humans. This effect has been attributed to the use of avoparcin in animal feed in Europe.

It is claimed that more than 80 per cent of infections with salmonella and campylobacter in humans come from food animals, and that a high proportion of them involve antimicrobial resistance. Using antimicrobials in food animals selects for resistant strains and enhances their persistence in the environment. But not all resistance can be ascribed to animal feed treatment. Inappropriate therapeutic use in humans accounts for much of the resistant infections in hospitals.

The claimed economic losses for food producers if antimicrobials were abolished could be minimised or even overcome by improvement in animal husbandry, quality of feed and hygiene.

Antibiotics should be used in animals only on precise veterinary indications, and drugs that have important implications for human therapy, such as fluoroquinolones and cephalosporins,should be prohibited in animal husbandry. Subtherapeutic use of any agents in growth promotion is to be condemned out of hand.

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Music and emotion

There seems to be no end to the interesting investigations into the effects of music good and bad, loud and soft, rhythmic or undisciplined, upon the human body and mind. A commentary published in Science for 12 October, on the work of some Canadian neuroscientists in respect of the physiological responses to different types of music, adds to the already complex picture of the role which music plays in ordinary human life and therapeutic procedures.

Recent research indicates that music, whether pleasant or unpleasant for the hearer, evokes clear physiological responses that may appeal to our deepest and most hidden instinctual drives. The notion itself is far from new, but there is always more to add to it from time to time.

In a series of experiments involving 10 musicians (five men and five women), subjects were asked to choose their personally most spine-tingling compositions. While they listened to the piece of their choice, their autonomic nervous responses, indicated by heart rate, respiration rate and depth, and muscular contractions, were measured. At the same time, brain activity determined by positron emission tomography was measured. It was found that accelerated autonomic activity was accompanied by increase in those areas of the brain concerned with emotion, arousal and anticipation of reward. Such responses are not related to physical survival as are those relating to food and sexual activity, but closely resemble the more primitive of human responses, although they are essentially cultural and not instinctive in nature.

Investigations have shown that exposure to musical dissonances stimulates those brain centres that are concerned with learning, memory and anxiety and that this is distinct from the stimulant effects of pleasurable music of melodic and rhythmic nature. Exposure to music of different calibres offers one useful means of studying the emotional backgrounds of individuals.

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