Molecular characterization of human Cryptosporidium spp. isolates after an unusual increase in late summer 2012.

Jeroen H Roelfsema,Wilfrid Van Pelt,Joke W B Van Der Giessen,Simone M Cacciò,Michiel Kroes,Hein Sprong,Laetitia M Kortbeek,Katsuhisa Takumi

doi:10.1186/s13071-016-1397-5

Abstract

BackgroundDuring the late summer 2012, a number of medical microbiological laboratories (MMLs) reported an unusual increase in cases of cryptosporidiosis, a gastrointestinal infection caused by the protozoan parasites Cryptosporidium spp. Prompted by this signal, the National Institute of Public Health and the Environment (RIVM) started an epidemiological investigation into possible causes. Simultaneously, samples diagnosed at MMLs were sent to RIVM for genotyping, aiming to further identify the possible source of the increase.MethodsGenotyping was performed by sequencing a fragment of the GP60 gene. Additional genotyping was performed on a subset of samples using six microsatellite markers. Population genetic analysis was performed using BEAST.ResultsThe majority of the samples were typed as C. hominis, and a single GP60 genotype (IbA10G2) largely predominated. Genotyping microsatellite markers further supported the circulation of a single genetic type. Population genetic analysis with genotypes found in previous years is inconsistent with a decrease in effective population size.ConclusionsThe conclusion of this finding is that the rise reflects more an overall increase and not a common source outbreak.

Highlights

During the late summer 2012, a number of medical microbiological laboratories (MMLs) reported an unusual increase in cases of cryptosporidiosis, a gastrointestinal infection caused by the protozoan parasites Cryptosporidium spp
We used a combination of a PCR on C. parvum, developed by Hadfield et al [24] and a PCR we developed for C. hominis
Origin of samples The unusually high increase of cryptosporidiosis was reported by MMLs in The Netherlands

Summary

Introduction

During the late summer 2012, a number of medical microbiological laboratories (MMLs) reported an unusual increase in cases of cryptosporidiosis, a gastrointestinal infection caused by the protozoan parasites Cryptosporidium spp. Prompted by this signal, the National Institute of Public Health and the Environment (RIVM) started an epidemiological investigation into possible causes. Cryptosporidium spp. are protozoan parasites and are widespread in a diverse range of hosts such as mammals including humans, birds and fish. Because of the global distribution of Cryptosporidium spp., these parasites can infect humans everywhere around the world. There are more than twenty recognized species of Cryptosporidium [2, 3]. Some species have a strong preference for a limited range of hosts, such as C. hominis, found

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