Bronchial asthma, or asthma in general, is the most common chronic childhood illness. It is a leading cause of visits to the emergency room and a cause for frequent hospital admissions among children 0-4 years old. It is also a frequent reason as to why students take an absence from school. Hence, it is not surprising that this is a common cause of concern for parents when their children are diagnosed with bronchial asthma.
Several factors have been implicated as causing bronchial asthma in children. Genetics play a huge role in its transmission with the strongest determining factor for developing asthma being atopy, a genetic predisposition to the development of immunoglobulin (Ig) E-mediated response to common airborne allergens. To date, more than one hundred gene sites have been linked to influencing the susceptibility to asthma. Other factors linked are environmental changes (e.g. wind, temperature fluctuations, and exposure to allergens or air pollutants), indoor inhalant allergens (e.g. house dust mite feces, cat dander, cockroach saliva, and dog dander), and outdoor fungus and pollens. Infections, especially respiratory, can precipitate and exacerbate asthmatic attacks. Emotional stress and hyperventilation due to physical stress and exercise are also triggers.
Despite a marked improvement in asthma management, the prevalence of the disease all over the world is still increasing. Childhood asthma seems more common in modern metropolitan locations and richer countries and is linked with other allergic conditions. On the other hand, children living in rural areas of developing countries and farming communities with domestic animals are less likely to experience asthma and allergy.
Braun-Fahrlaender et al. did the first study about the protective effect of farm living in the development of atopy and allergic disease in children. There were several studies, mostly done in Europe, which have repeatedly shown that there was a decrease in the prevalence of allergic sensitization, hay fever, and asthma in children living on a farm (hence termed as ‘farm effect’).
According to the ‘hygiene hypothesis’ stated by Strachan et al., the protective effect of farm living depends on environmental exposures to non-infectious microbial and non-microbial agents abundantly present in a rural environment. Studies of the asthma-protective and allergy-protective effects of a farming lifestyle show that protection is strongest when exposure happens during the prenatal period or during the first 2-3 years of life. The development of the immune system is the primary target. Contact of the mother with different farm animal species and barns plus consumption of farm-produced butter increased the production of cells in the baby’s cord blood, improving the immune system.
A recent study in Finland shows that contact with farm animals in early childhood reduces the risk of atopic sensitization, asthma diagnosed by a doctor, and allergic disease by the time the patient is thirty-one years of age. The protective effect that exposure to stables and drinking of unprocessed cow’s milk have for asthma and atopy was again proven by Illi et al. Their study showed that protection was typically associated with traditional farms that bred cattle and cultivated grain and corn for animal feeding and bedding. Contact with cows, contact with straw, and consumption of farm milk were enough to show the overall farm effect for asthma. Hence the question: what in those exposures induce the protection?
The environmental microbes were assessed and showed the diversity of microorganisms to which farm children were exposed. The microbial diversity (both bacteria and fungi) was higher in farmhouse dust and similar to those from animal sheds and barns. Cowshed dust is also rich in oligosaccharides, which protects the allergic airway from inflammation. The strong association between asthma protection and high environmental microbial diversity is the most suggestive clue that has come up about the factors and mechanisms regarding the farm effect. Studies in mice show that commensal bacteria (especially in the gut) act as gatekeepers of both immune development and immune function. More studies are being done in this field. Mazur et al. observed a decreased prevalence of atopy and allergic disease in children from families having three or more pets compared to children who only had one pet. Remo Frei, an immunologist based in Zurich, Switzerland, says early childhood contact with animals and the consumption of food of animal origin seems to regulate the inflammatory reactions of the immune system through sialic acid. We all look forward to more studies regarding the ‘farm effect’ in relation to asthma and allergies, most especially in the local scenario.
Asthma Prevention Tips for Parents
- Stick to your child’s asthma action plan. This should cover the directions given by your child’s doctor on what medicines to take and when, how to avoid triggers, what to do between flare-ups, and how to recognize and manage them if they happen. Following this plan will teach how to care for your child and know when to call the doctor for help.
- Take medicines as prescribed. The doctor should note which medicines your child needs and how to take them.
- Identify and avoid triggers. Identify your child’s triggers and help them avoid those things.
- Make sure your child gets a yearly flu vaccine.
- Use tools when necessary. Keep an asthma diary to keep track of your child’s attacks and see how well the treatment is working. Use a peak flow meter when feasible.
- Know the signs of a flare-up. This will help you adjust their medicine intake.
- Know what to do for a severe flare-up. It is a must to know your child's symptoms to see if they need medical care or a trip to the emergency room. Have quick-relief medicine handy at all times in case your child needs it.