Abstract
OBJECTIVE: The goal of this study was to evaluate temporal and spatial variations in the reporting of cases of giardiasis and cryptosporidiosis to a passive surveillance system, and to assess the relationship of those variations to source of drinking water, adjusting for socioeconomic variables. METHODS: The authors analyzed temporal and spatial patterns for 4,058 cases of giardiasis and 230 cases of cryptosporidiosis reported to the Massachusetts Department of Public Health for 1993-1996. They linked each reported case to a database containing information on source of residential water supply and socioeconomic characteristics and evaluated the association between these factors and reporting rates using regression techniques. RESULTS: Reports of giardiasis and cryptosporidiosis were highest for the mixed unfiltered drinking water supply category. Reports of giardiasis were associated with income levels. Increases in reporting for both giardiasis and cryptosporidiosis were seen in summer to early fall. During a suspected outbreak of cryptosporidiosis n the city of Worcester in 1995, a significant increase in reported cases was also observed in the Boston metropolitan area. Following the suspected outbreak, weekly giardiasis rates increased slightly in Worcester and the Boston metropolitan area, while reporting of cryptosporidiosis increased dramatically. CONCLUSIONS: Consistently collected passive surveillance data have the potential to provide valuable information on the temporal variation of disease incidence as well as geographic factors. However, passive surveillance data, particularly in the initial period of surveillance, may be highly sensitive to patterns of diagnosis and reporting and should be interpreted with caution.
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Selected References
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- Addiss D. G., Davis J. P., Roberts J. M., Mast E. E. Epidemiology of giardiasis in Wisconsin: increasing incidence of reported cases and unexplained seasonal trends. Am J Trop Med Hyg. 1992 Jul;47(1):13–19. doi: 10.4269/ajtmh.1992.47.13. [DOI] [PubMed] [Google Scholar]
- Birkhead G., Vogt R. L. Epidemiologic surveillance for endemic Giardia lamblia infection in Vermont. The roles of waterborne and person-to-person transmission. Am J Epidemiol. 1989 Apr;129(4):762–768. doi: 10.1093/oxfordjournals.aje.a115191. [DOI] [PubMed] [Google Scholar]
- Dennis D. T., Smith R. P., Welch J. J., Chute C. G., Anderson B., Herndon J. L., von Reyn C. F. Endemic giardiasis in New Hampshire: a case-control study of environmental risks. J Infect Dis. 1993 Jun;167(6):1391–1395. doi: 10.1093/infdis/167.6.1391. [DOI] [PubMed] [Google Scholar]
- Isaac-Renton J., Moorehead W., Ross A. Longitudinal studies of Giardia contamination in two community drinking water supplies: cyst levels, parasite viability, and health impact. Appl Environ Microbiol. 1996 Jan;62(1):47–54. doi: 10.1128/aem.62.1.47-54.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Krause W., Abraham A., Lehmann D. Cryptosporidienbefunde bei Kindern mit Enteritis-Symptomatik aus dem Regierungsbezirk Leipzig 1987-1992. Appl Parasitol. 1995 Feb;36(1):66–71. [PubMed] [Google Scholar]
- Lévesque B., Rochette L., Levallois P., Barthe C., Gauvin D., Chevalier P. Etude de l'incidence de la giardiase au Québec (Canada) et de l'association avec la source et la qualité de l'eau potable. Rev Epidemiol Sante Publique. 1999 Oct;47(5):403–410. [PubMed] [Google Scholar]
- Mac Kenzie W. R., Hoxie N. J., Proctor M. E., Gradus M. S., Blair K. A., Peterson D. E., Kazmierczak J. J., Addiss D. G., Fox K. R., Rose J. B. A massive outbreak in Milwaukee of cryptosporidium infection transmitted through the public water supply. N Engl J Med. 1994 Jul 21;331(3):161–167. doi: 10.1056/NEJM199407213310304. [DOI] [PubMed] [Google Scholar]
- Proctor M. E., Blair K. A., Davis J. P. Surveillance data for waterborne illness detection: an assessment following a massive waterborne outbreak of Cryptosporidium infection. Epidemiol Infect. 1998 Feb;120(1):43–54. doi: 10.1017/s0950268897008327. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roberts C. L., Morin C., Addiss D. G., Wahlquist S. P., Mshar P. A., Hadler J. L. Factors influencing Cryptosporidium testing in Connecticut. J Clin Microbiol. 1996 Sep;34(9):2292–2293. doi: 10.1128/jcm.34.9.2292-2293.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rodríguez-Hernández J., Canut-Blasco A., Martín-Sánchez A. M. Seasonal prevalences of Cryptosporidium and Giardia infections in children attending day care centres in Salamanca (Spain) studied for a period of 15 months. Eur J Epidemiol. 1996 Jun;12(3):291–295. doi: 10.1007/BF00145419. [DOI] [PubMed] [Google Scholar]
- Skeels M. R., Sokolow R., Hubbard C. V., Andrus J. K., Baisch J. Cryptosporidium infection in Oregon public health clinic patients 1985-88: the value of statewide laboratory surveillance. Am J Public Health. 1990 Mar;80(3):305–308. doi: 10.2105/ajph.80.3.305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Steiner T. S., Thielman N. M., Guerrant R. L. Protozoal agents: what are the dangers for the public water supply? Annu Rev Med. 1997;48:329–340. doi: 10.1146/annurev.med.48.1.329. [DOI] [PubMed] [Google Scholar]
- Wolfson J. S., Richter J. M., Waldron M. A., Weber D. J., McCarthy D. M., Hopkins C. C. Cryptosporidiosis in immunocompetent patients. N Engl J Med. 1985 May 16;312(20):1278–1282. doi: 10.1056/NEJM198505163122002. [DOI] [PubMed] [Google Scholar]
