: 545, 550 In a letter about landmarks in the history of smallpox vaccine, written to and quoted from by Derrick Baxby, Donald Henderson, chief of the Smallpox Eradication Unit from 1967 to 1977 wrote; "Copeman and Collier made an enormous contribution for which neither, in my opinion ever received due credit".Smallpox vaccine was inoculated by scratches into the superficial layers of the skin, with a wide variety of instruments used to achieve this. They ranged from simple needles to multi-pointed and multi-bladed spring-operated instruments specifically designed for the purpose.A major contribution to smallpox vaccination was made in the 1960s by Benjamin Rubin, an American microbiologist working for Wyeth Laboratories. Based on initial tests with textile needles with the eyes cut off transversely half-way he developed the bifurcated needle. This was a sharpened two-prong fork designed to hold one dose of reconstituted freeze-dried vaccine by capillarity. Easy to use with minimum training, cheap to produce ($5 per 1000), using one quarter as much vaccine as other methods, and repeatedly re-usable after flame sterilization, it was used globally in the WHO Smallpox Eradication Campaign from 1968.: 472–73, 568–72  Rubin estimated that it was used to do 200 million vaccinations per year during the last years of the campaign. Those closely involved in the campaign were awarded the "Order of the Bifurcated Needle". This, a personal initiative by Donald Henderson, was a lapel badge, designed and made by his daughter, formed from the needle shaped to form an "O". This represented "Target Zero", the objective of the campaign.
Antibiotic-associated diarrhea (AAD) results from an imbalance in the colonic microbiota caused by antibiotics. Microbiotal alteration changes carbohydrate metabolism with decreased short-chain fatty acid absorption and an osmotic diarrhea as a result. Another consequence of antibiotic therapy leading to diarrhea is overgrowth of potentially pathogenic organisms such as Clostridium difficile. It is defined as frequent loose and watery stools with no other complications. Cause
Clostridium difficile, also known more commonly as C. diff, accounts for 10 to 20% of antibiotic-associated diarrhea cases, because the antibiotics administered for the treatment of certain disease processes such as inflammatory colitis also inadvertently kill a large portion of the gut flora, the normal flora that is usually present within the bowel. With this lower level of "healthy" bacteria present, the overgrowth of C. diff is then responsible "for elaborating the enterotoxin". Treatment
Meta-analyses have concluded that probiotics may protect against antibiotic-associated diarrhea in both children and adults. Evidence is insufficient, however, regarding an effect on rates of C. difficile colitis.Efficacy of probiotic AAD prevention is dependent on the probiotic strain(s) used and on the dosage. Up to a 50% reduction of AAD occurrences has been found. No side effects have been reported. Caution is advised when using probiotics in immunocompromised individuals or those who have a compromised intestinal barrier because of the risk of an infection caused by the probiotic supplements. == References ==