Use of 99mTc-sulfur colloid to assess lymphatic dysfunction in filarial infection.

Investigations of lymphatic dysfunction in animals infected with filarial parasites has been hampered by a paucity of techniques to measure efficiency of lymphatic drainage. In this study a 99mTc-sulfur colloid technique was used to assess the efficiency of lymphatic drainage in Patas monkeys infected with filarial nematodes. In all 15 uninfected hind limbs there was rapid and consistent appearance of labeled colloid in the primary lymph node (popliteal) and subsequently in the secondary nodes (abdomino-pelvic) in 11 of 15 limbs. In contrast, in all eight limbs tested 1-9 months after infection there was reduced rate of migration of the colloid and initial appearance in the abdomino-pelvic region: subsequent accumulation was seen in the popliteal region in only four of the limbs. This data indicated that lymphatic vessels were blocked and that collateral vessels channeled the colloid to the secondary lymph nodes. The lymph flow patterns demonstrated by the isotope technique were supported at autopsy.

Chronic infection of cats with Brugia malayi and streptococcus.

An elephantoid condition was seen in the affected limbs of 5 of 6 cats at necropsy 12 to 18 months after initial infection with Brugia malayi. Repeated infection with Brugia and exposure to an opportunistic streptococcus appeared to enhance the production and persistence of edematous and fibrotic tissues surrounding the affected lymphatics.