Investigation of Respiratory Metastrongyloids and Other Endoparasites in Domestic Cats Living in the States of Rio de Janeiro and Rio Grande do Sul, Brazil

The metastrongyloids <i>Aelurostrongylus abstrusus</i> and <i>Troglostrongylus brevior</i>, and the capillariid <i>Capillaria aerophila</i>, are major respiratory nematodes infecting cats. In recent decades these nematodes have been recorded in several areas of the world and have called for epizootiological studies to update knowledge on their distribution. While <i>A. abstrusus</i> is known to occur in some areas of Brazil, the presence of <i>T. brevior</i> remains uncertain, and feline infections with <i>C. aerophila</i> have never been reported. This study has investigated the occurrence of lungworms with or without other endoparasitoses in domestic cat populations of selected areas of Brazil. Individual faecal samples were collected from 537 cats, i.e., 521 in metropolitan area of Rio de Janeiro and 16 in Porto Alegre (Rio Grande do Sul). All samples were examined with Sheather's flotation, and 521 of them also with the Baermann test. DNA was extracted from 425 Baermann sediments and molecularly examined for <i>A. abstrusus</i> and <i>T. brevior</i>. The most frequent parasites found at the copromicroscopy were Ancylostomatidae (n. 30, 5.8%), <i>Toxocara cati</i> (14, 2.7%), and <i>Cystoisospora felis</i> (n. 8; 1.5%). Larvae of <i>A. abstrusus</i> were identified by Baermann in 3 samples from Rio de Janeiro, while at PCRs, <i>A. abstrusus</i> DNA was amplified in 10 samples from Rio de Janeiro (n. 3), Seropédica (n. 3), Niterói (n. 3), and Porto Alegre (n. 1). The results indicate that <i>A. abstrusus</i> is enzootic in the investigated areas of Brazil and underline the usefulness of PCR when larvae are not detected by copromicroscopy or when only a single stool sample is analysed. Epizootiological implications, along with the absence of <i>T. brevior</i> in the examined cats and the presence of zoonotic endoparasites, are discussed.