USE OF PARASITE-SPECIFIC MONOCLONAL ANTIBOIDES TO STUDY INVASION AND EARLY DEVELOPMENT OF EIMERIA GRUIS IN THE FLORIDA SANDHILL CRANE (GRUS CANADENSIS)

Authors: Augustine, Patricia; KLEIN, P - PATUXENT WILDLIFE RES, MD; Danforth, Harry

Submitted to: Journal of Zoo and Wildlife Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Several species of coccidia are common parasites of the world's extant 15 species of cranes. These species, under certain conditions, may cause severe illness and mortality, especially in chicks under 2 weeks of age, and increase susceptibility to other stress factors. Unlike other coccidial infections that normally are restricted to the intestine, Eimeria infection in the Sandhill and Whooping cranes is disseminated throughout the visceral organs. Although parasite development during the acute stage of the infection has been described, little is known about the initial invasion by the sporozoites and their subsequent early development, primarily because these stages are difficult to identify by routine histologic staining. To overcome this obstacle, 2 parasite-specific monoclonal antibodies were used to visualize the coccidial stages in tissues of Florida sand hill cranes. The first antibody revealed that at 6 hours after crane chicks were infected with coccidia, sporozoites were found to invade only in limited areas of the intestine, and to accumulate in specific sites within these areas. The second antibody labeled parasite stages at 14 days after infection, not only in the intestine but in other organs. Because of its characteristics, the second antibody is likely to also label very early developmental stages, and disclose the point at which the parasite leaves the intestine and infects other organs. These data are crucial in planning strategies to control coccidiosis in captive and wild crane populations.

Technical Abstract: Eimeria gruis and E. reichenowi are common coccidial parasites of a number of species of cranes. Neither the site for invasion nor the dynamics of early development of the crane coccidia are known, primarily because of the difficulty of identifying sporozoites and early developmental stages by conventional staining methods. In the present study, monoclonal antibodies (McAb), elicited against Eimeria spp. of chickens and turkeys, were found to cross-react with sporozoites and developmental stages of E. gruis in the tissues of Florida sandhill cranes. These McAb were used to 1) define the area of the intestine that was invaded by sporozoites of E. gruis, and 2) demonstrate the feasibility of using McAb to study the early development of E. gruis in the intestines and visceral organs of cranes. At 6 hr postinoculation (PI), E. gruis sporozoites were found primarily from just proximal to Meckle's diverticulum in the jejunum to the ileocecal juncture. Fewer were found in the ceca and rectum, and none in the duodenum. Most of the sporozoites were in the middle third of the villi and within the lamina propria. At 14 days PI, developmental stages were detected in the intestine (ceca and jejunum), liver, and lungs, but not in the heart, kidney, or brain. Because McAb 1207 reacts with early as well as later developmental stages of chicken and turkey coccidia, it is probable that it would also react with early developmental stages of the crane coccidia, and, therefore, would be a valuable tool for examining the dynamics of early development by these species.