Hi.. Thanks for the query.. Well, blood in saliva that is more prominent while spitting and brushing is most probably due to deep gum infection or gingivitis.. It does not look like anything serious and looks from.oozing from gums only.. So my advice to you is to consult a Dentist and get evaluated.. If the gum infection is suspected to be deep then a Panoramic x ray can be done to check for bone resorption which can cause loosening and loss of teeth.. So a deep scaling and currettage followed by a course of antibiotics like Metronidazole and massaging the gums with antiseptic oral ointment like Chlorhexidine and antiseptic mouthwash gargle can help.. Hope this information is helpful to you.. Regards..