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An investigation of the possible interactions between combinations of vaccines and pyridostigmine bromide (PB) has been undertaken in the guinea pig. This study is part of a research programme funded by the UK Government to determine any effects of the pretreatment regimes given to UK Forces during the Persian Gulf conflict of 1990-1991. The study was designed to simulate PB administration and to model multiple vaccination protocols that were experienced by UK Forces, modelling a "worst case" situation in which all ten vaccines and PB were administered within a short period of time. Seven of the vaccines were health and hygiene (H+H) vaccines given to protect against endemic diseases and two vaccines to protect against the biological warfare agents anthrax and plague. In addition, pertussis vaccine was administered as an adjuvant to reduce the time to achieve immunity against anthrax. Four groups of eight animals were treated with 1/20th, 1/10th or 1/5th human doses of vaccines or vehicles, respectively. The PB or saline was delivered by implanted 28 day mini-osmotic pumps to achieve a mean red blood cell acetylcholinesterase (AChE) inhibition of around 30%. Body weight, temperature, immunological response, biochemical indices and spontaneous activity were monitored for 72 days. Although immunological responses to bacterial vaccines were observed, there were no remarkable findings in the parameters measured other than minor changes in body weight (4.9% decrease at the 1/5th human dose of vaccines) and temperature increases in response to vaccination. Animals in all groups remained generally healthy and active without visible adverse signs throughout the study. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.

Patent and pathologic infections of the human hookworm Necator americanus were established in the common marmoset (Callithrix jacchus). In a pilot study, a laboratory strain of N. americanus was compared with a fresh field isolate. Pathology was more severe in animals infected with a fresh isolate. In all animals, infection was associated with increased total plasma IgE and production of IgG specific to adult worm excretory/secretory (ES) products. Histamine was released by basophils in response to IgE, ES products, and a recombinant hookworm allergen, calreticulin. The pilot study indicated the potential of this animal model of hookworm infection and led us to investigate the consequences of infecting a further cohort with the fresh field isolate. This second study confirmed our initial findings, that it is possible to investigate the human hookworm N. americanus in a model exhibiting many of the characteristics of the immunology of hookworm infection in its definitive host.