# Detection of Giardia and Cryptosporidium in surface water of a subarctic city

## TL;DR

This study found Giardia and Cryptosporidium parasites in 60% of water samples from a subarctic city, highlighting potential health risks.

## Contribution

The study provides the first detection data of Giardia and Cryptosporidium in surface water from Anchorage, Alaska.

## Key findings

- Giardia or Cryptosporidium was detected in 60% of sampled waterbodies.
- Six waterbodies tested positive for both parasites.
- Fewer than 10 cysts or oocysts were found per 10L of water.

## Abstract

Giardia and Cryptosporidium spp. are globally distributed protozoan parasites that can cause gastrointestinal disease in humans and animals. These zoonotic parasites and their ecological relationships have been understudied in Alaska and elsewhere, despite being identified as priority zoonotic pathogens. We aimed to detect and characterize Giardia and Cryptosporidium spp. in waterbodies within Anchorage, Alaska, USA using two methods, including the Environmental Protection Agency (EPA) Method 1623 that relies on microscopy and a molecular detection approach. The molecular approach was ultimately unsuccessful and therefore only data obtained using Method 1623 are presented. Giardia or Cryptosporidium spp. was detected from nine of 15 urban streams and lakes sampled (60 %), six of which were positive for both parasites (40 %). Fewer than 10 cysts or oocysts were detected in 10 L of surface water. Further research to characterize Giardia and Cryptosporidium beyond the genus level would help elucidate the zoonotic potential and ecology of these parasites within the region and more broadly in Alaska.

•We sampled surface water for Giardia and Cryptosporidium spp. in sub-Arctic Alaska.•Low levels of one or both parasites were detected in 60 % of waterbodies sampled.•Further research could elucidate zoonotic potential of parasites in this region.

We sampled surface water for Giardia and Cryptosporidium spp. in sub-Arctic Alaska.

Low levels of one or both parasites were detected in 60 % of waterbodies sampled.

Further research could elucidate zoonotic potential of parasites in this region.