Facilitates hematophagy by preventing ADP-dependent platelet aggregation in the host. May reduce probing time by facilitating the speed of locating blood. a ribonucleoside 5'-triphosphate + 2 H2O = a ribonucleoside 5'-phosphate + 2 H(+) + 2 phosphate Salivary gland specific. Not detectable in females on the first day after eclosion, but is detectable on the second day. It is maximally expressed by day 4. The N-terminus is blocked. Causes an allergic reaction in human. Belongs to the 5'-nucleotidase family.