Home » Volumes » Volume 49 November/December 2016 » Meloidogyne eggs in human stool in Northeastern Brazil

Meloidogyne eggs in human stool in Northeastern Brazil

Fred Luciano Neves Santos1 Alina Maria Gonzaga Carlos de Souza2 Filipe Dantas-Torres3

1Laboratório de Patologia e Biointervenção, Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil. 2Laboratório Datalab, Grupo Promedica, Salvador, Bahia, Brazil. 3Laboratório de Imunoparasitologia, Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Pernambuco, Brazil.

DOI: 10.1590/0037-8682-0110-2016

Root-knot nematodes (Meloidogyne spp.) are among the most economically damaging genera of plant-parasitic nematodes worldwide1. Although they are not pathogenic to humans, their eggs may eventually be found in human stools2 and owing to their similarity with eggs of pathogenic nematodes must be correctly identified to avoid unnecessary treatments. Recently, researchers reported the presence of eggs similar to those of Trichostrongylus spp. (identified as Meloidogyne eggs) in three (0.5%) of 586 stool samples collected from East Kwaio, Solomon Islands2. From 2008 to 2014, 332,132 stool samples, referred to a private laboratory network (Datalab) in Salvador, Brazil, were examined using the Lutz method; 61 (0.02%) were positive for Meloidogyne eggs (Figure 1).

FIGURE 1 Meloidogyne egg showing a thin, hyaline shell and refractive internal corpuscles located between the shell and the morula, resembling lipid droplets. 

Meloidogyne eggs may be identified based on their shape, size, and absence or presence of characteristic internal structures3Meloidogyne eggs have thin hyaline shells without visible markings, elongate-ovoid with rounded ends. One of the sides can be concave or slightly flattened. They measure 82-120µm in length × 24-43µm in width and can be seen inside a juvenile cell mass in the first division phase or in a fully formed larva. They may present internal refractive corpuscles, located between the shell and the morula, which are important to distinguish them from eggs of Trichostrongylus spp. and hookworms. The presence of corpuscles, resembling air-sacs, on one of the poles, between the morula and the shell is very characteristic, although not always present. However, during its development, the concavity and the air-sacs may disappear, and the egg becomes plano-convex or even biconvex.


1. Jones JT, Haegeman A, Danchin EGJ, Gaur HS, Helder J, Jones MG, et al. Top 10 plant-parasitic nematodes in molecular plant pathology. Mol Plant Pathol 2013; 14:946-961. [ Links ]

2. Bradbury RS, Speare R. Passage of Meloidogyne eggs in human stool: forgotten, but not gone. J Clin Microbiol 2015; 53:1458-1459. [ Links ]

3. Pardinti VC, Ferreira CJ, Moura DM, Mendonça AR. Ocorrência de ovos de Trichostrongylus sp. e Meloidogynesp. em exames coproparasitológicos de rotina. Rev Méd Minas Gerais 1999; 9:100-102. [ Links ]

Received: March 23, 2016; Accepted: May 09, 2016

Corresponding author: Dr. Fred Luciano Neves Santos. e-mail: fred.santos@bahia.fiocruz.brflucianons@gmail.com

The authors declare that there is no conflict of interest