Baguioen, Michael A.2026-06-092026-06-092017-05Baguioen, M. A. (2017). Incidence of canine heartworm (Dirofilaria immitis) infection in Sapilang, Bacnotan, La Union. [Unpublished Undergraduate Thesis]. Don Mariano Marcos Memorial State University - North La Union Campus, Sapilang, Bacnotan, La Union. Lakasa ti Sirib, DMMMSU Institutional Repository.https://lakasa.dmmmsu.edu.ph/handle/123456789/1779This study was conducted to determine the: presence of canine heartworm (Dirofilaria immitis) in Sapilang, Bacnotan, La Union; incidence rate of canine heartworm infection in Sapilang, Bacnotan, La Union; incidence rate of canine heartworm infection in the different areas of Sapilang, Bacnotan, La Union; incidence of microfilaremia in antigen kit tested positive dogs; and occurrence of microfilaria in the peripheral circulation of antigen test kit positive dogs in relation to the time of blood collection. A total of 80 dogs from three areas aged above one year were used in the study. The presence of canine heartworm (D. immitis) was tested by the use of Antigen Test Kit (VetScan). The presence of microfiaria of the infected dogs was examined through Wet Blood Smear and Modified Knott’s Test. Data gathered were statistically analyzed using frequency and percentage under descriptive method. Canine heartworm infection was present in Sapilang, Bacnotan, La Union with a high incidence rate of 32.5 percent which varied in the three areas, where area I recorded the highest (65.52%), followed by area II (25.00%) while area III had the least incidence (3.70%). More than ninety percent (92. 31%) of the infected dogs had microfilaria in the circulating blood which were found during all the time of blood collection.en-USThesis