Is Gnathostoma turgidum an Annual Parasite of Opossums? Drastic Seasonal Changes of Infection in Didelphis virginiana in Mexico

• Published in: The Journal of parasitology Vol. 95; no. 4; pp. 908 - 912
• Main Authors: Nawa, Yukifumi, de la Cruz-Otero, Maríadel Carmen, Zazueta-Ramos, Magda Luz, Bojórquez-Contreras, Angel, Sicairos-Félix, Josefina, Campista-León, Samuel, Torres-Montoya, Edith Hilario, Sánchez-Gonzales, Sergio, Guzmán-Loreto, Roberto, Delgado-Vargas, Francisco, Díaz-Camacho, Sylvia Páz
• Format: Journal Article
• Language: English
• Published: Lawrence, KS American Society of Parasitologists 01.08.2009; Allen Press Inc
• Subjects: Animals; Biological and medical sciences; Diaphragm - parasitology; Didelphis - parasitology; Didelphis virginiana; Dry season; Female; Fundamental and applied biological sciences. Psychology; General aspects; General aspects and techniques. Study of several systematic groups. Models; Gnathostoma; Gnathostoma - anatomy & histology; Gnathostoma - physiology; Humans; Infections; Intestines - parasitology; Invertebrates; Life Cycles-Survey; Liver; Liver - parasitology; Longitudinal studies; Male; Mammalia; Mexico - epidemiology; Microscopy; Nematoda; Nematodes; Opossums; Parasite hosts; Parasites; Parasitology; Peritoneum - parasitology; Predation; Prevalence; Rainy seasons; Seasonal variations; Seasons; Spirurida Infections - epidemiology; Spirurida Infections - parasitology; Spirurida Infections - veterinary; Stomach; Stomach - parasitology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Winter; Worms; Central America; Mexico; America; Infection; Vertebrata; Didelphis virginiana; Mammalia; Seasonal variation; Marsupialia; Helmintha; Parasite; Nemathelminthia; Invertebrata; Nematoda; Gnathostoma
• ISSN: 0022-3395; 1937-2345
• DOI: 10.1645/GE-1988.1

Gnathostoma turgidum is a nematode that parasitizes the stomach of opossums, Didelphis virginiana. Despite its wide distribution in the Americas, its natural life cycle is poorly understood. Recently, we found an endemic area for G. turgidum infection in Sinaloa, Mexico (Díaz-Camacho et al., 2009). Based on sporadic surveys for several years, the prevalence was apparently high in summer and extremely low in winter. To confirm that this is really a seasonal variance, we conducted a longitudinal survey on G. turgidum infection in opossums from November 2007 to November 2008. The results showed amazing seasonal changes in the prevalence, with synchronized migration and maturation of worms in opossums. Between February and March, many juvenile worms, with occasional AL3, were found in the liver, but no worms were found in the stomach. Mature adult worms began to appear in the stomach around April and rapidly increased in number toward July, when all worms resided in the stomach. Then, the worms disappeared almost completely by November. These results suggest that G. turgidum is an annual parasite of the opossum, D. virginiana, in Mexico.