International Journal of Public Health

, Volume 56, Issue 1, pp 15–24 | Cite as

Toxocara infection in the United States: the relevance of poverty, geography and demography as risk factors, and implications for estimating county prevalence

  • Peter CongdonEmail author
  • Patsy Lloyd
Original Article



To estimate Toxocara infection rates by age, gender and ethnicity for US counties using data from the National Health and Nutrition Examination Survey (NHANES).


After initial analysis to account for missing data, a binary regression model is applied to obtain relative risks of Toxocara infection for 20,396 survey subjects. The regression incorporates interplay between demographic attributes (age, ethnicity and gender), family poverty and geographic context (region, metropolitan status). Prevalence estimates for counties are then made, distinguishing between subpopulations in poverty and not in poverty.


Even after allowing for elevated infection risk associated with poverty, seropositivity is elevated among Black non-Hispanics and other ethnic groups. There are also distinct effects of region. When regression results are translated into county prevalence estimates, the main influences on variation in county rates are percentages of non-Hispanic Blacks and county poverty.


For targeting prevention it is important to assess implications of national survey data for small area prevalence. Using data from NHANES, the study confirms that both individual level risk factors and geographic contextual factors affect chances of Toxocara infection.


Toxocara infection Poverty Ethnicity Geographic prevalence Bayesian 


  1. Acevedo-Garcia D (2000) Residential segregation and the epidemiology of infectious diseases. Soc Sci Med 51:1143–1161CrossRefPubMedGoogle Scholar
  2. Adams R, Howard N, Tucker G, Appleton S, Taylor A, Chittleborough C, Gill T, Ruffin R, Wilson D (2009) Effects of area deprivation on health risks and outcomes: a multilevel, cross-sectional, Australian population study. Int J Public Health 54:183–192CrossRefPubMedGoogle Scholar
  3. Beck A (2000) The human–dog relationship: a tale of two species, Chap 1. In: Macpherson C, Meslin F, Wandeler A (eds) Dogs, zoonoses and public health. CABI Publishing, Wallingford, pp 1–16CrossRefGoogle Scholar
  4. Blizzard L, Hosmer D (2006) Parameter estimation and goodness-of-fit in log binomial regression. Biometrical J 48:5–22CrossRefGoogle Scholar
  5. Brooke J (1984) 6 Years of canine-waste law: all in all, a cleaner New York, Sect. I. New York Times 25 (16 June)Google Scholar
  6. Centre for Disease Control (2007) Documentation, codebook, and frequencies; surplus sera laboratory component: antibody to Toxocara larva migrans. NHANES III, Series 11 Data Files 26A. Available via Accessed 30 March 2010
  7. Cooper P (2008) Toxocara canis infection: an important and neglected environmental risk factor for asthma? Clin Exp Allergy 38:551–553CrossRefPubMedGoogle Scholar
  8. De Andrade Lima Coelho R, De Carvalho L, Perez E, Araki K, Takeuchi T (2005) Prevalence of toxocariasis in northeastern Brazil based on serology using recombinant Toxocara canis antigen. Am J Trop Med Hyg 72:103–107PubMedGoogle Scholar
  9. Despommier D (2003) Toxocariasis: clinical aspects, epidemiology, medical ecology, and molecular aspects. Microbiol Rev 16:265–272CrossRefGoogle Scholar
  10. Deutz A, Fuchs K, Auer H, Kerbl U, Aspock H, Kofer J (2005) Toxocara infestations in Austria: a study on the risk of infection of farmers, slaughterhouse staff, hunters and veterinarians. Parasitol Res 97:390–394CrossRefPubMedGoogle Scholar
  11. Fan C, Lan H, Hung C, Chung W, Liao C, Du W, Su K (2004) Seroepidemiology of Toxocara canis infection among mountain aboriginal adults in Taiwan. Am J Trop Med Hyg 71:216–221PubMedGoogle Scholar
  12. Genchi C, Di Sacco B, Gatti S, Sangalli G, Scaglia M (1990) Epidemiology of human toxocariasis in northern Italy. Parassitologia 32:313–319PubMedGoogle Scholar
  13. Glickman L, Schantz P (1981) Epidemiology and pathogenesis of zoonotic toxocariasis. Epidemiol Rev 3:230–250PubMedGoogle Scholar
  14. Graubard B, Korn E, Midthune D (1997) Testing goodness-of-fit for logistic regression with survey data. In: Proceedings of the section on survey research methods. American Statistical Association, Alexandria, pp 170–174Google Scholar
  15. Habluetze A, Traldia G, Ruggieri S, Attilia A, Scuppa P, Marchetti R, Menghini G, Esposito F (2003) An estimation of Toxocara canis prevalence in dogs, environmental egg contamination and risk of human infection in the Marche region of Italy. Vet Parasitol 113:243–252CrossRefGoogle Scholar
  16. Havasiova K, Dubinsky P, Stefancíkova A (1993) A seroepidemiological study of human Toxocara infection in the Slovak Republic. J Helminthol 67:291–296CrossRefPubMedGoogle Scholar
  17. Herrmann N, Glickman L, Schantz P, Weston M, Domanski L (1985) Seroprevalence of zoonotic toxocariasis in the United States: 1971–1973. Am J Epidemiol 122:890–896PubMedGoogle Scholar
  18. Hotez P (2007) Neglected diseases and poverty in ‘‘the other America’’: the greatest health disparity in the United States? PLoS Negl Trop Dis 1(3):e149. doi: 10.1371/journal.pntd.0000149
  19. Hotez P (2008) Neglected infections of poverty in the United States of America. PLoS Negl Trop Dis 2(6):e256. doi: 10.1371/journal.pntd.0000256
  20. Hotez P, Wilkins P (2009) Toxocariasis: America’s most common neglected infection of poverty and a helminthiasis of global importance? PLoS Negl Trop Dis 3(3):e400. doi: 10.1371/journal.pntd.0000400
  21. Ibrahim J, Lipsitz S, Chen M (1999) Missing covariates in generalized linear models when the missing data mechanism is nonignorable. J Roy Stat Soc B 61:173–190CrossRefGoogle Scholar
  22. Kaplan M, Kamanli A, Kalkan A, Kuk S, Gülkesen A, Ardiçoğlu O, Demırdağ K (2005) Toxocariasis seroprevalence in patients with rheumatoid arthritis. Turkiye Parazitol Derg 29:251–254PubMedGoogle Scholar
  23. Lunn D, Thomas A, Best N, Spiegelhalter D (2000) WinBUGS—a Bayesian modelling framework: concepts, structure, and extensibility. Stat Comput 10:325–337CrossRefGoogle Scholar
  24. Lynch N, Wilkes L, Hodgen A, Turner K (1988) Specificity of Toxocara ELISA in tropical populations. Parasite Immunol 10:323–337CrossRefPubMedGoogle Scholar
  25. Macpherson C (2005) Human behaviour and the epidemiology of parasitic zoonoses. Int J Parasitol 35:1319–1331CrossRefPubMedGoogle Scholar
  26. Magnaval J, Galindo V, Glickman L, Clanet M (1997) Human Toxocara infection of the central nervous system and neurological disorders: a case–control study. Parasitology 115:537–543CrossRefPubMedGoogle Scholar
  27. Merlo J, Yang M, Chaix B, Lynch J, Råstam L (2005) A brief conceptual tutorial on multilevel analysis in social epidemiology: investigating contextual phenomena in different groups of people. J Epidemiol Community Health 59:729–736CrossRefPubMedGoogle Scholar
  28. Mizgajskaa H (2001) Eggs of Toxocara in the environment and their public health implications. J Helminthol 75:147–151Google Scholar
  29. Morenoff J, Lynch J (2004) What makes a place healthy? Neighborhood influences on racial/ethnic disparities in health over the life course. In: Anderson N, Bulatao R, Cohen B (eds) Critical perspectives on racial and ethnic differences in health in late life. National Academy Press, Washington, DC, pp 406–449Google Scholar
  30. Nathwani D, Laing R, Currie P (1992) Covert toxocariasis as a cause of recurrent abdominal pain in childhood. Br J Clin Pract 46:271PubMedGoogle Scholar
  31. Nelson S, Greene T, Ernhart C (1996) Toxocara canis infection in preschool age children: risk factors and the cognitive development of preschool children. Neurotoxicol Teratol 18:167–174CrossRefPubMedGoogle Scholar
  32. Nicoletti A, Sofia V, Mantella A, Vitale G, Contrafatto D, Sorbello V, Biondi R, Preux P, Garcia H, Zappia M, Bartoloni A (2008) Epilepsy and toxocariasis: a case–control study in Italy. Epilepsia 49:594–599CrossRefPubMedGoogle Scholar
  33. Noordin R, Smith H, Mohamad S, Maizels R, Fong M (2005) Comparison of IgG-ELISA and IgG4-ELISA for toxocara serodiagnosis. Acta Trop 93:57–62CrossRefPubMedGoogle Scholar
  34. Paquet-Durand I, Hernández J, Dolz G, Zuñiga J, Schnieder T, Epe C (2007) Prevalence of Toxocara spp., Toxascaris leonina and ancylostomidae in public parks and beaches in different climate zones of Costa Rica. Acta Trop 104:30–37CrossRefPubMedGoogle Scholar
  35. Plaut M, Zimmerman E, Goldstein R (1996) Health hazards to humans associated with domesticated pets. Annu Rev Pub Health 17:221–215Google Scholar
  36. Roddie G, Stafford P, Holland C, Wolfe A (2008) Contamination of dog hair with eggs of Toxocara canis. Vet Parasitol 152:85–93CrossRefPubMedGoogle Scholar
  37. Stensvold C, Skov J, Møller L, Jensen P, Kapel C, Petersen E, Nielsen H (2009) Seroprevalence of human Toxocariasis in Denmark. Clin Vaccine Immunol 16:1372–1373CrossRefPubMedGoogle Scholar
  38. Tolan M, Laufer R (2009) Toxocariasis: an overview. eMedicine (Parasitology). Available via Accessed 30 March 2010
  39. United States Department of Agriculture (USDA) (2004) Rural poverty at a glance. Rural Development Research Report Number 100, USDA Economic Research Service, Washington, DCGoogle Scholar
  40. Won K, Kruszon-Moran D, Schantz P, Jones J (2008) National seroprevalence and risk factors for zoonotic Toxocara infection. Am J Trop Med Hyg 79:552–557PubMedGoogle Scholar

Copyright information

© Swiss School of Public Health 2010

Authors and Affiliations

  1. 1.Department of Geography, Center for StatisticsQueen Mary University of LondonLondonUK
  2. 2.National Minority Quality ForumWashington, DCUSA
  3. 3.Department of Epidemiology and Biostatistics, School of Public Health and Health ServicesGeorge Washington UniversityWashington, DCUSA

Personalised recommendations