T. K. Jeffers

PULMONARY LESIONS IN DISSEMINATED VISCERAL COCCIDIOSIS OF SANDHILL AND WHOOPING CRANES

Fifty cranes, consisting of 46 sandhill (Grus canadensis) and four whooping cranes (Cms americana), were studied. Eighteen sandhill cranes and the four whooping cranes were naturally infected with disseminated visceral coccidiosis (DVC). The remaining sandhill cranes were chicks experimentally infected with oocysts of Eimeria reichenowi and/or E. gruis; five chicks served as controls. There were no clinical signs attributed to respiratory infection. Necropsy of naturally infected adult birds revealed nodules in many organs, including the lung, air sacs, trachea and nares. Artificially infected sandhill cranes and the whooping crane chicks that died from DVC had congestion and consolidated areas in the lung with frothy fluid in the airways. Grossly visible nodules were observed from 10 days postinoculation. Granulomatous pneumonia and tracheitis were observed with light microscopy. Lesions were associated with merogonic and gametogonic stages of eimerian coccidia. Granulomas and granulomatous foci contained parasitized large mononuclear cells. Merogonic stages were seen in lymphoid cells by ultrastructural examination. Oocysts were observed in the trachea and bronchial mucosa and admixed with exudate in the airways, indicating that crane eimerians can complete their life cycle at these sites. Of the few eimeriid coccidia that have extraintestinal stages of development in birds and mammals, only the species in cranes complete their life cycle in both the digestive and respiratory tracts.

The infectivity of Eimeria sporozoites recovered from Monensin medicated chickens 1

Sporozoites of embryo-adapted lines of Eimeria tenella, E. brunetti and E. necatrix were recovered from monensin medicated chickens. The viability of these sporozoites was compared with that of sporozoites recovered from unmedicated birds by assessing their infectivity in chicken embryos. Sporozoites of the three species of Eimeria recovered from 100 parts/10(6) monensin-medicated birds produced infections in embryos which were 94 to 98% less severe than infections resulting from the inoculation of sporozoites recovered from unmedicated chickens. A concomitant scanning electron microscope study revealed no apparent ultrastructural damage to the exposed sporozoites. Timed medication experiments in chickens showed that medication with monensin for the period covering sporozoite penetration in vivo was almost completely effective, being comparable to continuous medication. Medication started before infection (to ensure tissue concentrations of monensin) but terminating 5 to 7 hours before the oocysts were inoculated was ineffective.