The fate of intraperitoneally inoculated infective third-stage larvae (L,) of the nematode Brugia malayi Lichtenstein and the status of the peritoneal macrophage function were investigated in the susceptible rodent hosts Mastomys natalensis Roberts and Meriones unguiculatus Milne-Edwards (jird). Jirds and M. natalensis were inoculated intraperitoneally with 125 and 250 L, and the worm burden and peritoneal macrophage function in the two species were compared at different days post-in-oculation (DPI). None of the infected M. natalensis had adult worms in the peritoneal cavity; very few degenerating L, surrounded by peritoneal cells were recovered 7 and 15 DPI. In contrast, all the infected jirds showed the parasite in different stages of development and the worm burden at different days PI was more in 250 L, dose group than in 125 L3 dose group. The phagocytic function of peritoneal macrophages of normal M. natalensis was twice higher than that of jirds. This function was found significantly suppressed in both host species at 15 DPI; at 35 DPI, the activity was still at this low level in the jird, while that in M. natalensis reverted to uninfected age- and sex-matched control levels. These findings demonstrate that the peritoneal environment of M. natalensis is not conducive to the development of B. malayi and this is probably related to high macrophage activity in the peritoneum of this host compared to that found in the jird.
The nematode Philometra rubra (Leidy, 1856) (Philometridae) is redescribed from subgravid females found in the abdominal cavity of the fish Morone saxatilis (Walbaum) from South Carolina, USA in November 2008. The species is characterized by the presence of 14 cephalic papillae arranged in two circles, a relatively long oesophagus with a distinct anterior inflation, and well-developed papilla-like caudal projections. Cephalic papillae of the external circle differ from those in other congeners in that the dorso-lateral and ventro-lateral papillae are large, dome-shaped, whereas the dorso-dorsal and ventro-ventral papillae are small.