The Epizootiology of Eustrongylidosis in Wading Birds (Ciconiiformes) in Florida

Abstract

A total of 2,167 individuals representing 15 species of wading birds was examined for infection with the nematode Eustrongylides ignotus in Florida (USA). Ten of the species were infected with the greatest prevalences occurring in great blue herons (Ardea herodius) (33%), great egrets (Casmerodius albus) (22%), and snowy egrets (Egretta thula) (19%). Among nestlings, prevalences increased with age. This parasite was estimated to cause at least 80% mortality among nestling ciconiiforms at one colony in Everglades National Park, and was found in 15% of nestling ardeids throughout the state. Despite wide sampling efforts, infected fish (second intermediate hosts) were only found at six sites in Florida, all of which had been physically altered, such as with canals and ditches, and had an anthropogenic (human-caused) source of nutrient pollution. Colonies near sources of infected fish experienced significantly higher prevalences of eustrongylidosis that did colonies for which no source of infected fish could be found within 20 km. Higher prevalences were found at freshwater and estuarine mainland colonies than at marine colonies. Densities of aquatic oligochaetes, which may act as first intermediate hosts, were highest at sites containing infected fish and at sites with a source of nutrient pollution. Conservation and management of wading bird species should include consideration of this disease, epizootics of which seem to be linked to nutrient pollution.

Helminth and arthropod parasites of the brown pelican, Pelecanus occidentalis , in Puerto Rico, with a compilation of all metazoan parasites reported from this host in the Western Hemisphere

“…Our specimens were in poor condition and could not be identified to the species level, but a search of the literature failed to reveal a report of this nematode in pelicans. These worms cause epizootics in nesting wading birds (Spalding et al, 1993). Immature forms of Eustrongylides ignotus (Jägerskiöld, 1909) were reported as a new Caribbean record in Puerto Rican fishes by BunkleyWilliams & Williams (1994).…”

The belowground intersection of nutrients and buoyancy in a freshwater marsh

“…The 122 ha area converted to open water is about 100 cm deep, and so the amount of carbon released from the marsh is about 450 thousand mt C year -1 . There are other issues, including that the un-managed distribution of pathogens into a nutrient-and organicrich system is a fertile growth medium for organisms potentially compromising the health of people and avians (Anza et al 2014;Coyner et al 2003;Spalding et al 1993;Petrie et al 2016), and that contaminates local streams-a subject that can be explored in more detail elsewhere. The consequences potentially apply to other marshes with significant vertical water movements and eutrophic conditions.…”

Altered Predation Susceptibility of Mosquitofish Infected With Eustrongylides Ignotus

“…In Florida (USA) the number of reproducing wading birds (Ciconiiformes) has declined dramatically over the past 40 yr (Ogden, 1994). Spalding et al (1993) reported that infection with the parasitic nematode Eustrongylides ignotus was a major mortality factor in nestling wading birds in Florida, causing losses of over 80% in some colonies. Birds become infected with this parasite after consuming fish.…”