Platelet Aggregation in Dogs Infected with Dirofilaria immitis

Abstract

The ability of platelets to aggregate in response to various stimuli was evaluated in 3 Dirofilaria immitisinfected dogs as well as 4 healthy dogs. Platelets from the normal dogs aggregated irreversibly at a concentration of 20μM of adenosine diphosphate (ADP), and reversibly with the monophasic pattern at 2.5μM of ADP. The aggregation of platelets was also observed at 3 different concentrations of collagen (2.5, 5 and 10μ/ml). Platelets from the infected dogs aggregated biphasically and irreversibly at 2.5μM of ADP, at which concentration of ADP only a reversible aggregation of platelets was induced from the normal dogs. The maximum aggregation rate and percent aggregation by 3 min of platelets from the infected dogs were remarkably higher than those from the normal dogs. The elevated platelet aggregation rate at 2.5μM ADP in 2 infected dogs decreased to the level of that in the normal dogs after the administration of acetylsalicylic acid at 0.5mg/kg body weight once a day for 5 to 8 weeks.