First record of helminths parasitizing Vanellus chilensis (Aves, Charadriiformes) in Acre state, southwestern Brazilian Amazon

The southern lapwing, Vanellus chilensis, is a bird frequently seen in most of Brazil. Although it is widely distributed in other Brazilian biomes, including some parts of the Brazilian Amazon, it has only been recorded in the western Amazonian state of Acre since 2000. We report the presence of intestinal parasites in individuals of V. chilensis from the Cazumbá-Iracema Extractive Reserve in Acre through a coproparasitological analysis. Seven of the nine sampled individuals were parasitized. We observed larvae of Strongyloides sp. (28.5% of the samples), and eggs of Ascaridia sp. (28.5%), Ancylostoma sp. (14.2%), and Choanotaenia sp. (42.8%). These parasites are reported for the first time parasitizing V. chilensis in Brazil. The parasitized birds may act as reservoirs and were recorded in a peridomicile area, which may facilitate their contact with domestic birds.

As V. chilensis does not undertake any major postreproductive migration, it is considered to be a sedentary species, although it may travel short distances to avoid flooding and other changes in the local environment (Guimarães et al. 2016). It is a typical bird from South America, but its distribution has already expanded to Central and North VOL. 51(3) 2021: 255 -259 ACTA AMAZONICA America (Wiersma and Kirwan 2020). It has also extended to the Amazon biome (Guilherme and Czaban 2015;Guimarães et al. 2016), where it has colonized areas that have been deforested for cattle ranching, with rivers and roads providing dispersal corridors that have allowed the species to reach the interior of the biome (Guilherme and Czaban 2015; Borges et al. 2017). Vanelus chilensis is considered to be an invasive species in the Brazilian state of Acre, where it can now be found on river margins during the dry season, as well as in cattle pastures and urban environments (Guilherme and Czaban 2015; Guilherme 2016).
The helminth fauna of V. chilensis is little known. The existing studies are restricted to some regions of Brazil and Argentina, with records of individuals parasitized by Platyhelminthes Gegenbaur, 1859, Acanthocephala Rudolphi, 1808 and Nematoda Rudolphi, 1808 (Travassos and Freitas 1940;Rêgo 1968;Pinto and Noronha 1972;Vicente et al. 1995;Avancini 2009;Silveira 2016). Here we report the first record of the presence of intestinal parasites in V. chilensis in the Amazon biome based on coproparasitological tests.   (ii) spontaneous sedimentation; and (iii) centrifugal flotation with saturated sucrose solution under optical microscopy. All the parasite specimens observed during these analyses were photographed and measured using 10x and 40x magnification (Axio Scope A1). The parasites were identified based on the diagnostic characteristics described by Foret (2005) and Zajac and Conboy (2011). Testimony material was deposited in the Helminthological Collection of the Instituto Oswaldo Cruz (CHIOC 38988 -38991).
Eleven lapwings were captured in the mist nets, of which, nine (82%) provided fecal samples. The analysis of these samples revealed the presence of parasites in 77.8% (n = 7) of the cases. Four helminth taxa were identified, three nematodes and one cestode (Figure 3). Eggs of the cestode Choanotaenia sp. were the most common, present in three (42.8%) of the seven samples. Larvae of Strongyloides sp. were observed in two (28.5%), eggs of Ascaridia sp. in two (28.5%) and eggs of Ancylostoma sp. in one (14.2%) of the samples. Overall, 58 helminth eggs or larvae were found, of which almost half (48%, n = 28) were Choanotaenia sp. eggs, 24% (n = 14) were Ascaridia sp. eggs, 17% (n = 10) were Ancylostoma sp. eggs, and 10% (n = 6) were larvae of Strongyloides sp. (Figure 3).
Helminths have already been recorded parasitizing V. chilensis in a number of Brazilian states (Table 1), based on necropsy and the analysis of internal organs. Overall, six species of Nematoda, four species of Digenea, four species of Cestoda, and four of Acanthocephala were recorded. Travassos and Freitas (1940) reported the infection of two southern lapwings by cestodes during a scientific survey of a railroad in Mato Grosso do Sul, Brazil, but did not identify the taxon.
We observed V. chilensis in peridomicile areas in very close proximity to human residences, which may facilitate their contact with domestic birds. Ascaridia galli, Strongyloides sp., and Choanotaenia sp. are all known to parasitize domestic birds (Olivares et al. 2006;Siqueira and Marques 2016;Marques et al. 2019;Neto et al. 2020) and, in the same region in Acre where the individuals of V. chilensis were captured, we have recorded parasites of three taxa (Strongyloides sp., Ascaridia sp., and Strongylida) in other bird species (Souza et al. 2020), which indicates possible transmission between local birds that share the same environment.
Wild animals are considered to be potential hosts and reservoirs of parasitic diseases, and wild birds, whether freeranging or in captivity, may act as reservoirs of diseases that may be transmitted to humans (Souza et al. 2018). This emphasizes the importance of further research to catalogue the parasitological fauna of wild birds in the study region, together with molecular analyses to verify the possible presence of parasites with zoonotic potential that may infect the local human population.

ACKNOWLEDGMENTS
We would like to thank Mrs. Maria Marilene Rufino, the adminsitrator of the Cazumbá-Iracema Extractive Reserve, for her support during fieldwork, with special thanks to the residents of the Cazumbá Reserve for their help with the bird captures, in particular, Mr. José Acácio and Mrs. Francisca da Rocha.