Water-borne diseases related to recreational water

This section presents statistics on three potentially water-borne diseases in New Zealand: campylobacteriosis, cryptosporidiosis and giardiasis. 

These gastrointestinal diseases cause symptoms like diarrhoea and vomiting. Contaminated recreational water is one way that people may contract these diseases. Other ways include contact with drinking water, farm animals, sick animals, faecal matter, or other symptomatic people; and eating contaminated food [1].

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Over 8600 cases of campylobacteriosis, cryptosporidiosis and giardiasis were notified in 2014
Recreational water contact reported for over 190 cases

Over 8600 cases of campylobacteriosis, cryptosporidiosis and giardiasis were notified in 2014

In 2014, there were 6552 notifications of campylobacteriosis (142 per 100,000 population), 542 notifications of cryptosporidiosis (14 per 100,000 population) and 1541 notifications of giardiasis (37 per 100,000 population) (Figure 1). Campylobacteriosis cases have accounted for the majority of notified water-borne disease notifications since 2001.

The rate of campylobacteriosis cases dropped from 2006 to 2008. This decrease was likely due to interventions to reduce contamination of poultry around this time [2].

Figure 1

Recreational water contact reported for over 190 cases

In 2014, there were 114 notifications of campylobacteriosis (2.8 per 100,000 population), 17 notifications of cryptosporidiosis (0.5 per 100,000 population) and 60 notifications of giardiasis (1.5 per 100,000 population) with recreational water contact as a risk factor in New Zealand.

Not all cases reported risk factors, so these numbers may be an underestimate.  

Figure 2

Information about the data

Notifications of campylobacteriosis, cryptosporidiosis and giardiasis 

Source: Institute of Environmental Science and Research (ESR)

This section presents the number of cases of campylobacteriosis, cryptosporidiosis and giardiasis notified in 2010.

  • Notifications of diseases may underestimate the true number of cases of diseases, as not everyone will go to a doctor when sick.
  • Cases that had been overseas during the incubation period were excluded as they were unlikely to be infected in New Zealand. 
  • Not every case reported a ‘risk factor’ (such as untreated drinking water and recreational water contact). The reported number of water-borne disease cases by risk factor is smaller than the actual number.

References

 1. ESR. 2015. Notifiable and Other Diseases in New Zealand: Annual Report 2014. Porirua, New Zealand. Available online: https://surv.esr.cri.nz/surveillance/annual_surveillance.php

2. Sears A, Baker MG, Wilson N, Marshall J, Muellner P, Campbell DM, et al. 2011. Marked campylobacteriosis decline after interventions aimed at poultry, New Zealand. Emerging Infectious Diseases 17(6).