Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Apr 4;13(4):821.
doi: 10.3390/microorganisms13040821.

Multilocus Variable-Number Tandem-Repeat Analysis as an Investigation Tool in Cryptosporidium parvum Outbreaks in Finland and Sweden in 2022

Kristiina Suominen  1 , Anni Vainio  1 , Pirkko Hokkanen  2 , Riikka Åberg  2 , Sanna Isosomppi  3 , Eeva Särelä  3 , Wioleta Kitowska  1   4 , Ana Cristina Gonzalez-Perez  1   5 , Jukka Ollgren  1 , Ioana Bujila  6 , Karin Troell  7   8 , Anette Hansen  9 , Mats Lindblad  10 , Ruska Rimhanen-Finne  1
Affiliations

Multilocus Variable-Number Tandem-Repeat Analysis as an Investigation Tool in Cryptosporidium parvum Outbreaks in Finland and Sweden in 2022

Kristiina Suominen et al. Microorganisms. .

Abstract

Cryptosporidium is a significant cause of foodborne outbreaks. The 60 kDa glycoprotein gene (gp60) is most often used for subtyping Cryptosporidium species but is not always sufficient for defining clusters and infections sources. The Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) scheme has been developed to better differentiate between subtypes. A cryptosporidiosis outbreak, with 35 cases, was detected in Finland in September 2022. At the same time, in Sweden, three cryptosporidiosis outbreaks, with 107 cases, were detected, leading to international collaboration. In both countries, salad mixes were suspected as being the outbreak source. In the Finnish outbreak, the suspected salad mixes were produced in Sweden. In the Swedish outbreaks, salad mixes from two different producers were suspected. Twenty-nine patient samples which were positive for Cryptosporidium parvum (11 from Finland and 18 from Sweden) were sent for MLVA. The Finnish outbreak samples had different gp60 subtypes and MLVA profiles compared to the Swedish samples. In our investigation, MLVA differentiated C. parvum subtypes in more detail than gp60 typing. MLVA suggested no connection between the Finnish and Swedish outbreaks. A traceback investigation supported this conclusion. To detect outbreaks and identify infection sources, the timely subtyping of patient samples is crucial and should be implemented in routine surveillance and outbreak investigations.

Keywords: MLVA scheme; cohort study; cryptosporidiosis; disease outbreaks; epidemiology; foodborne; molecular typing; subtype.

PubMed Disclaimer

Conflict of interest statement

W.K. and A.C.G.-P. are fellows of the ECDC Fellowship Programme, supported financially by the European Centre for Disease Prevention and Control. The views and opinions expressed herein do not state or reflect those of the ECDC. The ECDC is not responsible for the data and information collation and analysis and cannot be held liable for the conclusions or opinions drawn. All of the other authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Figures

Figure 1
Figure 1
Cryptosporidiosis cases (N = 35) by date of symptom onset, September–October 2022, Helsinki, Finland.
Figure 2
Figure 2
Traceback of salad mix batches linked to Cryptosporidium parvum cases at Hotel X and Café Y in Helsinki, Finland, and in three outbreaks in Sweden, from September to October 2022. Either salad mix batch 1 or 2 was served at Hotel X, which is shown with dashed arrows. Abbreviations beginning with FI or SE in parentheses refer to the patient samples in Table 2.
See this image and copyright information in PMC

References

    1. Checkley W., White A.C., Jr., Jaganath D., Arrowood M.J., Chalmers R.M., Chen X.M., Fayer R., Griffiths J.K., Guerrant R.L., Hedstrom L., et al. A review of the global burden, novel diagnostics, therapeutics, and vaccine targets for cryptosporidium. Lancet Infect. Dis. 2015;15:85–94. doi: 10.1016/S1473-3099(14)70772-8. - DOI - PMC - PubMed
    1. Feng Y., Ryan U.M., Xiao L. Genetic diversity and population structure of Cryptosporidium. Trends Parasitol. 2018;34:997–1011. doi: 10.1016/j.pt.2018.07.009. - DOI - PubMed
    1. Cacciò S.M., Chalmers R.M. Human cryptosporidiosis in Europe. Clin. Microbiol. Infect. 2016;22:471–480. doi: 10.1016/j.cmi.2016.04.021. - DOI - PubMed
    1. Shrivastava A.K., Kumar S., Smith W.A., Sahu P.S. Revisiting the global problem of cryptosporidiosis and recommendations. Trop. Parasitol. 2017;7:8–17. - PMC - PubMed
    1. Hunter P.R., Hughes S., Woodhouse S., Raj N., Syed Q., Chalmers R.M., Verlander N.Q., Goodacre J. Health sequelae of human cryptosporidiosis in immunocompetent patients. Clin. Infect. Dis. 2004;39:504–510. doi: 10.1086/422649. - DOI - PubMed

LinkOut - more resources