Comparison of paired whole milk and dried filter paper samples for anti-enterotoxin and anti-rotavirus activities

Milk specimens, 75 from cows immunized against cholera toxin and 35 from a human population in which enterotoxigenic Escherichia coli and rotaviral infections are endemic, were collected as paired filter paper and frozen whole milk samples. Each pair was tested for antibody activity against heat-labile E. coli and Vibrio cholerae enterotoxins. Additionally, 12 of the 35 paired human milk samples stored as frozen whole milk and dried on filter paper were tested for anti-rotavirus immunoglobulin A. Anti-enterotoxin and anti-rotavirus immunoglobulin A titers in milk dried on filter paper compared favorably with those of their frozen whole milk pairs. Filter paper samples offered considerable advantages for field collection, transportation, and storage over frozen liquid samples.