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. 2023 Oct 13;32(3):e005623.
doi: 10.1590/S1984-29612023057. eCollection 2023.

A molecular and morphological study of Ascaris suum in a human-pig contact scenario in northeastern Brazil

Polyanna Araújo Alves Bacelar  1   2 , Jéssica Pereira Dos Santos  2 , Deiviane Aparecida Calegar  1 , Denilson de Araújo E Silva  2 , Daniella Nobre Leal  2 , Brenda Bulsara Costa Evangelista  2 , Elis Regina Chaves Dos Reis  3 , Jacenir Reis Dos Santos Mallet  2   4 , Filipe Anibal Carvalho-Costa  1 , Lauren Hubert Jaeger  5 , Kerla Joeline Lima Monteiro  2
Affiliations

A molecular and morphological study of Ascaris suum in a human-pig contact scenario in northeastern Brazil

Polyanna Araújo Alves Bacelar et al. Rev Bras Parasitol Vet. .

Abstract
in English, Portuguese

The aim of the present study was to assess morphologic and genetic data on ascariasis in swine (Sus scrofa domesticus) and humans in low-resource rural and periurban communities in the state of Piauí, Brazil. Our cross-sectional survey included 100 fecal samples obtained from swine and 682 samples from humans. Fifteen pigs were necropsied. Human and porcine fecal samples were examined to identify Ascaris eggs. Parasites obtained in the swine necropsies were studied using scanning electron microscopy (SEM), and the mitochondrial gene encoding the cytochrome oxidase 1 (cox1) enzyme was partially amplified and sequenced for molecular taxonomy and phylogenetic analyses. The overall prevalence of Ascaris eggs in the swine fecal samples was 16/100 (16%). No Ascaris eggs were identified in the human fecal samples. SEM of six worms recovered from pigs demonstrated morphological characteristics of A. suum. Cox1 sequences were compatible with A. suum reference sequences. Original and reference (GenBank) nucleotide sequences were organized into clusters that did not segregate the parasites by host species or and region. The largest haplogroups were dominated by haplotypes H01, H02 and H31. In the communities studied, there was no epidemiological evidence of the zoonotic transmission of ascariasis at the human-swine interface.

O presente estudo teve como objetivo acessar dados morfológicos e genéticos sobre a ascaridíase em suínos (Sus scrofa domesticus) e humanos, em comunidades rurais e periurbanas no estado do Piauí. O estudo transversal incluiu 100 amostras fecais de suínos e 682 amostras obtidas de humanos. Quinze suínos foram necropsiados. Amostras fecais suínas e humanas foram examinadas para detecção de ovos de Ascaris. Os parasitas adultos, obtidos nas necropsias, foram estudados através de microscopia eletrônica de varredura (MEV), e o gene mitocondrial codificante da enzima citocromo oxidase 1 (cox1) foi parcialmente amplificado e sequenciado para análises filogenéticas e de taxonomia molecular. A prevalência de Ascaris em amostras fecais de suínos foi 16/100 (16%), não sendo identificado nenhum caso de infecção por este parasita em humanos. A análise por MEV de parasitas recuperados de suínos demonstrou características morfológicas de Ascaris suum. As sequências nucleotídicas de cox1 foram compatíveis com A. suum. As sequências originais e de referência (obtidas no GeneBank) foram organizadas em clusters que não segregaram os parasitas por hospedeiro ou região geográfica. Os maiores haplogrupos foram dominados pelos haplótipos H01, H02 e H31. Nas comunidades estudadas, não foi evidenciada transmissão zoonótica de A. suum na interface suíno-humana.

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Conflict of interest statement

Conflict of interest: None declared.

Figures

Figure 1
Figure 1. Phylogenetic tree generated from Ascaris spp. mitochondrial cox1 nucleotide sequences (383 bp). Bootstrap values >70% are reported. Toxocara canis, Bayliascaris procyonis and Parascaris equorum as outgroups. Further details of reference strains can be found in Supplementary Material Table S1.
Figure 2
Figure 2. Median-joining network from Ascaris spp. mitochondrial cox1 nucleotide sequences (383 bp). The area of the circle is proportional to the sequence number.
Figure 3
Figure 3. Scanning electron micrographs demonstrating the morphological characteristics of the mouthparts of adult parasites obtained by necropsy of swine. The morphology of the mouth opening and denticles is compatible with Ascaris suum.
See this image and copyright information in PMC

References

    1. Almeida MM, Monteiro KJL, Bacelar PAA, Santos JP, Freitas SPC, Evangelista BBC, et al. Interactions between malnutrition, soil-transmitted helminthiasis and poverty among children living in periurban communities in Maranhao State, Northeastern Brazil. Rev Inst Med Trop São Paulo. 2020;62:e73. doi: 10.1590/s1678-9946202062073. - DOI - PMC - PubMed
    1. Alves EBS, Conceição MJ, Leles D. Ascaris lumbricoides, Ascaris suum, or “Ascaris lumbrisuum”? J Infect Dis. 2016;213(8):1355. - PubMed
    1. Alves JR, Macedo HW, Ramos AN, Jr, Ferreira LF, Gonçalves MLC, Araújo A. Parasitoses intestinais em região semi-árida do Nordeste do Brasil: resultados preliminares distintos das prevalências esperadas. Cad Saude Publica. 2003;19(2):667–670. doi: 10.1590/S0102-311X2003000200034. - DOI - PubMed
    1. Ansel M, Thibaut M. Value of the specific distinction between Ascaris lumbricoïdes Linné 1758 and Ascaris suum Goeze 1782. Int J Parasitol. 1973;3(3):317–319. doi: 10.1016/0020-7519(73)90109-4. - DOI - PubMed
    1. Arizono N, Yoshimura Y, Tohzaka N, Yamada M, Tegoshi T, Onishi K, et al. Ascariasis in Japan: is pig-derived Ascaris infecting humans? Jpn J Infect Dis. 2010;63(6):447–448. doi: 10.7883/yoken.63.447. - DOI - PubMed