A recent study published in Pediatrics suggests that children who are exposed to pets in the first year of life have fewer upper respiratory tract infections (URI). Most children have between 3-6 episodes of URIs before they are 1 year old. Factors such as exposure to older siblings, daycare, lack of breastfeeding, parental history of asthma, and smoking exposure have been associated with an increased incidence of URIs. In the past 10 years there have been a great deal of research evaluating differences in the immune response in children who are exposed to dogs and those who are not.
The study evaluated almost 400 children and were grouped into the amount of indoor exposure to cats or dogs: 1. No contact 2. Low contact (16 hours/day). The patients were also grouped into 1. No breastfeeding 2. Some breastfeeding and 3. Exclusive breastfeeding. Other factors were also examined such as month of birth and family histories of asthma or allergies. The most significant group that had the fewest ear infections and required fewer doses of antibiotics were the “Low contact” dog group. The study indicated that cats have an overall protective effect in preventing wheezing but less protective in infections than dog exposure. The group where the dogs spent less than 6 hours indoors had the most protective effect against infections and URIs. This may be due to the fact that the dog spent more time outdoors and brought in more dirt into the home.
It appears that the evidence indicates that early animal contacts may help the immune system mature, which leads to a better immune response and shorter durations of infections. Although these studies are preliminary, it supports other research that indicates that living in an environment that is too sterile may not be as beneficial as we thought. Studies looking into the “hygiene hypothesis” believe that individuals who live in industrial countries are not exposes to as many microbes therefore their immune systems are not routinely challenged. This may lead to autoimmune and allergic conditions where the immune system attacks parts of the body or become hypersensitive to routine allergens.