Alterations in plasma copper, zinc, amino acids, and seromucoid during Rocky Moutain spotted fever in guinea pigs.

Guinea pigs inoculated with virulent Rickettsia rickettsii responded with a significant increase in plasma copper concentration within 1 day, preceding fever and detectable rickettsemia by 2 and 4 days, respectively. A decrease in serum zinc concentration coinciding with peak rickettsemia was detectable on Day 5. Evidence of altered host nitrogen metabolism during this illness included a doubling of plasma seromucoid concentration and a significant rise in the plasma phenylalanine/tyrosine ratio.