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. 2022 Sep 8:19:155-160.
doi: 10.1016/j.ijppaw.2022.09.001. eCollection 2022 Dec.

Death by massive air sac fluke (Trematoda: Bothriogaster variolaris) infection in a free-ranging snail kite (Rostrhamus sociabilis)

Eduardo A Díaz  1 , Gustavo Donoso  1 , Juan D Mosquera  2 , Darío X Ramírez-Villacís  2   3 , Gerardo González  1 , Sonia Zapata  2 , Diego F Cisneros-Heredia  1   4
Affiliations

Death by massive air sac fluke (Trematoda: Bothriogaster variolaris) infection in a free-ranging snail kite (Rostrhamus sociabilis)

Eduardo A Díaz et al. Int J Parasitol Parasites Wildl. .

Abstract

Helminths are not usually considered important pathogens for birds of prey. There is a single published report of mortality in raptors due to an air sac trematode infection. We report a well-documented death case from massive infection by an air sac trematode of the family Cyclocoelidae in a wild-caught, juvenile male Snail Kite (Rostrhamus sociabilis) in Ecuador. The necropsy of a Snail Kite revealed more than 200 trematodes among air sacs, lungs, heart, gizzard, proventriculus, and liver. Within air sacs and lungs, mature flukes were associated with sacculitis, bronchitis, pneumonia, and atelectasis. Using an integrative taxonomic approach with morphological and molecular data, we identified the parasites as Bothrigaster variolaris (Trematoda: Cyclocoelidae: Ophthalmophaginae). This case provides the first evidence for the pathologic presence of air sac trematodes associated with morbidity in birds of prey in South America. Our results suggest that cyclocoelids may cause debilitation and significant clinical lesions in birds of prey, with potentially fatal consequences.

Keywords: Airways; Bird of prey; Cyclocoelidae; Parasitosis; Pneumatic bones.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Image 1
Graphical abstract
Fig. 1
Fig. 1
Trematodes in serosa of heart and proventriculus of Snail Kite (Rostrhamus sociabilis): A. Close up image of a trematode (arrow) in the pericardium during necropsy. B. Histologic capture of a trematode (arrow) present in the serosa of the proventriculus (H&E).
Fig. 2
Fig. 2
Trematodes in respiratory system and pneumatic bone of a Snail Kite (Rostrhamus sociabilis): A. Macroscopic image of the lungs, with presence of trematodes (arrows) found during necropsy. B. Trematodes (arrows) colonising the lumen of a tertiary bronchus (10x H&E) C. Trematodes (arrows) in an abdominal air sac (10x H&E) D. A parasite (arrow) in the coracoid bone (10x H&E).
Fig. 3
Fig. 3
Trematodes in the liver of a Snail Kite (Rostrhamus sociabilis): A. Trematodes (arrows) in the serosa of proventriculus, gizzard and liver found during postmortem procedure. B. Miracidium (arrow) in the liver parenchyma (40x H&E).
Fig. 4
Fig. 4
Trematodes in the right abdominal air sac, serosa of gastrointestinal tract and celomic cavity of a Snail Kite (Rostrhamus sociabilis).
Fig. 5
Fig. 5
Bayesian inference phylogenetic tree of the Echinostomatoidea superfamily showing the position of trematodes extracted from Snail Kite from Ecuador (in bold). The tree was built using small subunit of the ribosomal RNA gene (18 S rDNA) in Beast v1.10.4. Bayesian posterior probability values ≥ 0.5 are shown in branches. Family, genus, and species from each sequence are listed along with their accession number. Family delimitations are indicated with grey boxes. Sequences of Schinostomatoidea and Opisthorchioidea were used as outgroups. Scale bar indicates number of expected substitutions per site.
Fig. 6
Fig. 6
Full body (A), anterior end (B) and posterior end (C) of trematode Bothrigaster variolaris from a Snail Kite (Rostrhamus sociabilis). T = midbody testes, V = ventral sucker, p = pharynx, O = postesticular ovary, E = eggs.
See this image and copyright information in PMC

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