Towards a US national estimate of the risk of endemic waterborne disease – sero-epidemiologic studies

Abstract

Worldwide literature on serological methods and sero-surveys on waterborne pathogens has been reviewed. Outbreak investigation and research reports have also been examined to aid understanding of the serological response and transmission dynamics. The aim was to seek an estimate of seroprevalence and to determine if this could inform the US national estimate of risk for endemic waterborne infection associated with public water supplies. Antibody responses indicate infection, both symptomatic and asymptomatic, so probably give a truer indication of prevalence. Outbreak data can probably be regarded as the upper bound for seroprevalence estimations. Antibody is not necessarily protective per se but is a good indicator for at least partial resistance to symptomatic infection; absence of antibody will normally imply susceptibility.Pathogens transmitted by water are commonly transmitted by other routes. However, the fact that other transmission routes are more common does not detract from the potential protective effect of immunity when waterborne transmission occurs. Data indicate that seroprevalence varies widely, reflecting geographic, social and hygiene factors, but is generally greater where surface water sources are used rather than groundwater. Areas of low seroprevalence may expect a high attack rate in the event of contamination of their water supply.Key words | Campylobacter, Cryptosporidium, ELISA, endemic infection, E. coli 0157, Giardia, molecular studies, noroviruses, outbreaks, sero-epidemiology, seroprevalence, waterborne pathogens, western blot ABBREVIATIONS DEFINITIONS AND GENERAL ASPECTS OF IMMUNOLOGYEpidemiology, at its simplest, is the study of the occurrence (number and frequency) and distribution of cases by person This paper is in the public domain: verbatim copying and redistribution of this paper are permitted in all media for any purpose, provided this notice is preserved along with the paper's original DOI. Anyone using the paper is requested to properly cite and acknowledge the source as J. The outcome of the contamination of water supply and transmission to consumers depends on complex dynamics with various, usually ill characterised, factors-the organism, the exposed persons (and their levels of immunity) and the environment (Casemore 1994(Casemore , 1995Meinhardt et al. 1996).In order to better understand the natural history of waterborne infections and the complexities of the dynamics of transmission (see Figure 1), epidemiological investigations can be enhanced by serologic studies . The purpose of this paper concerns the national estimate of risk of endemic infection from water. However, reports on immunological studies and on the investigation of outbreaks are fundamental to the understanding of endemic infection and illness. In general terms, prevalence in outbreaks likely represents the upper boundary for endemic infection estimates.Sero-epidemiology is a form of study in which the demonstration of antibodies to the organism of interest is used as a surrogate or marker for the d...

A Cryptosporidium hominis outbreak in North-West Wales associated with low oocyst counts in treated drinking water

“…The excess of adult cases suggests that the water supply had not previously been a source of infection for a sufficient period of time to permit an increase in susceptible persons in the population. This is in contrast to experience with other more contaminated, usually lowland, surface water supplies, consumers of which generally show an increased sero-prevalence and lower attack rates in the event of an outbreak (Casemore 2006).…”

“…It has not usually been possible to relate oocyst numbers to risk level and the numbers found in association with outbreaks has varied widely. Three factors in particular are important: oocyst viability, species of isolate, and immunity of those exposed (Casemore 2006).…”

Multiplex Assay Detection of Immunoglobulin G Antibodies That Recognize Giardia intestinalis and Cryptosporidium parvum Antigens

“…In contrast to the Cryptosporidium assays just described, most of the assays that detect antibodies to Giardia have used crude trophozoite or cyst antigens, and a sensitive and specific recombinant protein-based serologic assay has not yet been reported (12,17). The immunodominant Giardia antigen is the variant-specific surface protein (VSP), a cysteine-rich (11 to 12% Cys) protein that covers the entire surface of the parasite (reviewed in reference 2).…”

Drinking Water Quality and Occurrence of Giardia in Finnish Small Groundwater Supplies

“…The impact of small supplies on the disease burden of their users remains unknown. The life-long consumption of drinking water from a contaminated source could, on the other hand, also lead to acquired immunity [23,24].…”