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Volume 22, Number 8—August 2016
Letter

Baylisascaris procyonis Parasites in Raccoons, Costa Rica, 2014

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To the Editor: Baylisascaris procyonis (Ascaridoidea: Ascarididae) parasites are facultatively heteroxenous nematodes that are widely distributed in the United States and Canada, where prevalence rates reach 70%–90%. They colonize the small intestine of their final host, the northern raccoon (Procyon lotor), whose feces can contain up to 25 × 103 eggs/g. Under ideal environmental conditions (100% humidity and 24°C), eggs become infective in soil (1,2). When ingested by other mammalian hosts, third-stage larvae can produce pathologic changes called larva migrans, which can lead to chronic neurologic disorders and even death (1,3). B. procyonis parasite infection of humans occurs by the fecal–oral route (ingestion of eggs in contaminated food) (1). Small children are particularly vulnerable through accidental geophagia. Public health concerns arise where raccoon and human populations overlap.

As elsewhere, raccoons in Costa Rica have expanded their range into human-dominated areas, becoming common in the Greater Metropolitan Area, an ≈2,000-km2 portion of the Central Valley, home to 2.6 million persons. During the past decade, the government wildlife agency (Ministerio de Ambiente y Energía [MINAE]) reported a steep increase in raccoon-related complaints (4).

We examined raccoons for which a nuisance complaint was received by MINAE at 8 locations inside the Greater Metropolitan Area and report the southernmost range extension of B. procyonis parasites (previously not detected at latitudes below 31° N; Costa Rica [8°–11° N] is substantially farther south [2]). B. procyonis parasites in kinkajous (Potos flavus) have been reported, but that parasite was subsequently determined to be B. potosis (5,6).

For 10 months in 2014, raccoons were trapped in wooded areas and residential gardens by using baited traps (Havahart, Lititz, PA, USA) over 315 trap-nights. Fecal samples were collected from the animals and from communal latrines near the trapping sites, and the Sheather flotation technique was used to detect eggs in the feces (1). During raccoon necropsies, any adult roundworms (including B. procyonis) found in the gastrointestinal tract were fixed in 70% and 100% ethanol for morphologic and molecular identification, respectively.

Parasites were examined by light microscopy. Those identified as B. procyonis were counted and sexed. Voucher specimens of B. procyonis were deposited in the Natural History Museum, London, UK (accession no. NHMUK 2015.2.23 1–2). Nematodes were assigned to the genus Baylisascaris on the basis of genus-specific features. Species-specific features of B. procyonis (shape of lip denticles, male pericloacal rough areas, and male tail shape [7]) were used to distinguish B. procyonis from B. columnaris (6,7). Eggs were identified according to size and shell thickness. The shell has a characteristic soft granular surface (3). Mean size of the oval eggs was 57.0 μm (range 59.34–55.48) by 70.3 μm (range 51.5–72.1) (13).

We used DNA extracted from B. procyonis parasites to amplify the mitochondrial cytochrome c oxidase 2 gene, ribosomal ITS1–5.8S-ITS2, and ribosomal 28S genes by using the primers and protocol described by Franssen et al. (8). We found 100% identity between the sequences from B. procyonis parasites from Costa Rica and those from North America (GenBank accession nos. AF179908 [cytochrome c oxidase 2 region], JQ403615 [ITS1–5.8S-ITS2 region], and KC434770 [28S region]).

We found B. procyonis parasites in 10 of 20 captured raccoons (Table), from which 137 adult worms (78 females, 59 males) were recovered. Infection intensity was 1–60 parasites/raccoon (mean 12.5). Average specimen length was 11.6 cm (range 8.1–20 cm). B. procyonis infection was found in raccoons at all 8 locations.

Our sampling locations included 2 playgrounds and 1 school yard. A previous study found high prevalence of Toxocara spp. nematode eggs in dog feces from the same geographic region (9). Because egg identification can be difficult and that study was based exclusively on morphologic description without molecular confirmation or electron microscopy, it is possible that some B. procyonis eggs were misidentified as Toxocara spp. Both Toxocara spp. and B. procyonis parasites can cause larva migrans, the latter being more aggressive. In the Greater Metropolitan Area and Costa Rica in general, free-ranging dogs are common, including at playgrounds and school yards, sites also vulnerable to nocturnal visits by raccoons. Dogs can have patent B. procyonis parasite infections and can play a role in transmission of the parasite from raccoons to humans.

In Costa Rica, cases of larva migrans have been reported. The Unidad de Investigación y Análisis, Registros y Estadísticas de Salud at the National Children’s Hospital, San José, Costa Rica, reported 135 cases of larva migrans ocularis and 21 cases of visceral larva migrans caused by nonspecifically identified ascarids during 2005–2014 (unpub. data). However, these diagnoses were based on IgG serologic testing results (Martinez J., National Children’s Hospital; pers. comm., 2015), which do not identify ascarid species. Western blot testing would improve accuracy (10).

The eco-epidemiology of B. procyonis parasites in tropical settings is relevant to public health because it might play a yet-unrecognized role in larva migrans pathology, which can be severe. Increased contact between raccoons and humans also warrants further investigation to improve understanding and minimize zoonotic risk.

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Acknowledgments

This work was funded by a grant from the Fondo Institucional de Desarrollo Académico-2013-Universidad Nacional-Universidad de Costa Rica, Fondo del Sistema-Consejo Nacional de Rectores (ACUERDO-VI-167-2013).

The study was approved by Research Ethics Board permits (FCSA-EMV-CBA-007-2013); the Universidad Nacional de Costa Rica, Universidad de Costa Rica Institutional Committee for the Use and Care of Laboratory Animals (CICUA-130-13), and the Institutional Review Board of MINAE (ACCVC-OH-512).

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Mario BaldiComments to Author , Gilbert Alvarado, Steve Smith, Mario Santoro, Natalie Bolaños, Carlos Jiménez, Sabine E. Hutter, and Chris Walzer

Author affiliations: University of Veterinary Medicine, Vienna, Austria (M. Baldi, S. Smith, S.E. Hutter, C. Walzer); Universidad Nacional, Heredia, Costa Rica (M. Baldi, N. Bolaños, C. Jiménez); Universidad de Costa Rica, San Pedro, Costa Rica (G. Alvarado); Istituto Zooprofilattico Sperimentale del Mezzogiorno, Naples, Italy (M. Santoro)

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References

  1. Kazacos  KR. Baylisascaris procyonis and related species. In: Samuel WM, Pybus MJ, Kocan AA, editors. Parasitic diseases of wild mammals. 2nd ed. Ames (IA): Iowa State University Press; 2001. p. 301–41.
  2. Hernandez  SM, Galbreath  B, Riddle  DF, Moore  AP, Palamar  MB, Levy  MG, Baylisascaris procyonis in raccoons (Procyon lotor) from North Carolina and current status of the parasite in the USA. Parasitol Res. 2013;112:6938. DOIPubMed
  3. Roussere  GP, Murray  WJ, Raudenbush  CB, Kutilek  MJ, Levee  DJ, Kazacos  KR. Raccoon roundworm eggs near homes and risk for larva migrans disease, California communities. Emerg Infect Dis. 2003;9:151622. DOIPubMed
  4. Soto  M. Raccoons causing problems inside the Greater Metropolitan Area [in Spanish] [cited 2015 Jul 11]. http://wfnode01.nacion.com/2010-09- 05/AldeaGlobal/NotasSecundarias/AldeaGlobal2507351.aspx
  5. Tokiwa  T, Nakamura  S, Taira  K, Une  Y. Baylisascaris potosis n. sp., a new ascarid nematode isolated from captive kinkajou, Potos flavus, from the Cooperative Republic of Guyana. Parasitol Int. 2014;63:5916. DOIPubMed
  6. Overstreet  RM. Baylisascaris procyonis (Stefanski and Zarnowski, 1951) from the kinkajou, Potos flavus, in Colombia. J Parasitol. 1970;37:1925.
  7. Anderson  RC, Chabaud  AG, Willmott  S. Keys to the nematode parasites of vertebrates: archival volume. Wallingford (UK): CAB International; 2009. p. 463.
  8. Franssen  F, Xie  K, Sprong  H, van der Giessen  J. Molecular analysis of Baylisascaris columnaris revealed mitochondrial and nuclear polymorphisms. Parasit Vectors. 2013;6:124. DOIPubMed
  9. Paquet-Durand  I, Hernández  J, Dolz  G, Zuñiga  JJ, Schnieder  T, Epe  C. Prevalence of Toxocara spp., Toxascaris leonina and ancylostomidae in public parks and beaches in different climate zones of Costa Rica. Acta Trop. 2007;104:307. DOIPubMed
  10. Dangoudoubiyam  S, Kazacos  KR. Differentiation of larva migrans caused by Baylisascaris procyonis and Toxocara species by Western blotting. Clin Vaccine Immunol. 2009;16:15638. DOIPubMed

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Cite This Article

DOI: 10.3201/eid2208.151627

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Table of Contents – Volume 22, Number 8—August 2016

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Page created: July 15, 2016
Page updated: July 15, 2016
Page reviewed: July 15, 2016
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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