Helmintos parasitos de pombos (Columba livia) de criatórios de Minas Gerais, Brasil: diagnóstico, tratamento e dinâmica de infecção

Abstract

Domestic pigeons (Columba livia) are birds associated with humanity since ancient times and are still bred for different purposes, including pigeon racing. Although a rich helminth fauna is recorded in these birds worldwide, aspects of the taxonomy, diagnosis and treatment of these parasites are not completely known. In the present study, a coproparasitological survey was carried out in pigeons from seven breeding sites from localities of the Mesoregião Metropolitana de Belo Horizonte, Minas Gerais, between September 2021 and February 2022. Fecal samples from birds were collected and processed by the spontaneous sedimentation method. Three aliquots of fecal sediment were evaluated under an optical microscope per sample to investigate the helminth developmental stages. In order to complement the diagnosis, pigeons found dead during the period were necropsied for recovery and specific identification of adult worms. Attempts of anthelmintic treatment using the commercial formulation containing Praziquantel and Pyrantel Pamoate were carried out in one of the breeding sites. New fecal exams were made at 7- and 14-days post-treatment (DPT) to evaluate the efficacy of this therapeutic intervention. In total, 211 fecal samples of pigeons were collected and examined, of which 81 (38%) were positive for helminths. All seven breeding sites had positive samples, with the percentage of infection ranging from 2% to 100%. Six species of helminths were identified in the evaluated samples. The renal trematode Paratanaisia bragai was found in 4 dovecotes, with a percentage of positive samples ranging from 3% to 92%. Infection by cestodes identified as Raillietina allomyodes was observed in only one breeding site (percentage of infection: 33%). The intestinal nematode Ascaridia columbae was found in 5 breeding sites, with infection rates ranging from 2 to 42%. In one of the dovecotes, two nematodes found in the proventriculus, Synhimantus (Dispharynx) nasuta and Tetrameres fissispina, were also found (infection rates of 8% and 17%, respectively). Eggs of Capillaridae, morphometrically indistinguishable from Baruscapillaria obsignata, were observed in 5 breeding sites and the percentage of positivity ranged between 3% and 52%. Regarding the anthelmintic treatment of pigeons infected by the helminths mentioned above, the therapeutic schedule used in one of the breeding sites evaluated resulted in negativity in all animals up to 14 DPT. In addition, an improvement in the consistency of the droppings was observed in most animals. On the other hand, the re-study of these same pigeons three months after the treatment revealed reinfection with P. bragai, in addition to a high frequency of infection with A. columbae. Although a new treatment cycle also resulted in negativity after a short time, the process of reinfection with P. bragai was verified in a new coproparasitological survey carried out nine months later, pointing out difficulties inherent to the control of helminthiases of pigeons. The data obtained represent the first survey carried out in pigeon farms in the region and may serve as subsidies for future studies involving the improvement of the health profile of breeding pigeons. Furthermore, this is the first controlled study concerning the anthelmintic treatment of birds infected with P. bragai.