The lymphatic pathology of chronic Brugia pahangi infection in the dog.

The dog infected with Brugia pahangi is an excellent model for studying the clinical and immunological pathogenesis of lymphatic filarial infection and disease. Dogs demonstrated a range of clinical changes including varying levels of microfilaraemia, episodic lymphadenopathy, lymphangitis, and limb oedema similar to the clinical spectrum reported in man. Histologically, tissues from parasite-infected dogs were characterized by fibrosis of the lymph nodes and their afferent and efferent lymphatic ducts in the infected limbs. Some nodes were atrophied while others were characterized by reactive hyperplasia. Duct walls of some afferent lymphatics were thickened with a mononuclear inflammatory infiltrate. Parasite antigen deposition was detected in the subcapsular sinuses and middle of germinal centres of infected popliteal lymph nodes, using an immunohistochemical technique.