Exploring transmission dynamics of the Sarcoptes scabiei mite in humans by combining molecular typing and epidemiological variables, the Netherlands 2016-2023

Abstract

Background: Scabies, an infestation of the mite Sarcoptes scabiei, has seen an increase in clinical diagnoses in the Netherlands since 2011. This study aimed to analyse PCR-positive S. scabiei skin samples through partial genome sequencing and to link findings to patient epidemiological characteristics.

Methods: Skin samples were collected from individuals in the Netherlands between January 2016 and January 2023. On the PCR-positive S. scabiei skin samples, partial mitochondrial cytochrome c oxidase subunit 1 gene (cox1) sequencing was performed to assess genetic variability. Epidemiological information was collected through interviews. We examined associations between cox1 subtypes, epidemiological factors and treatment outcomes.

Results: Sequencing results were obtained from 128 patients, with epidemiological information available for 55 (43%) of these patients. Fifteen distinct cox1 subtypes were identified. Subtype 01 was most prevalent (45%) and present across all age groups and social settings. The remaining subtypes were less common and not consistently found in all contexts. Five clusters were identified, each with identical cox1 subtypes. Comparative analysis with GenBank sequences revealed genetic similarities with strains from Australia, the USA and China, suggesting the global distribution and transmission of specific subtypes. A substantial proportion (73%) of patients with scabies required multiple treatments to eradicate the infestation, with no subtype-related differences.

Conclusions: This is the first study linking S. scabiei sequencing results to patient epidemiological data. Several subtypes clustered in specific geographic regions and social contexts, underscoring localised transmission patterns. Further research with larger sample sizes is needed to enhance our understanding of the transmission of this mite. This study provides valuable insights that will strengthen scabies control efforts.

Keywords: Sarcoptes scabiei; cox1; Cytochrome c; Mite; Molecular typing; Scabies.

Fig. 1

Neighbour joining tree of partial cox1 sequences in samples from 128 patients, 1 sample from the Northern chamois (Rupicapra rupicapra) and 6 reference sequences from GenBank. Members of each clade (A-D) are shown in different branch colours. Accession numbers: AB779595.1: water buffalo Egypt; AY493381.1: hominis 8 Panama; AY493382.1: hominis 208 Australia; AY493388.1: hominis 10 Australia; AY493395.1: canis 9 USA; KJ748528.1: canis 5 China. Cox1, Cytochrome c oxidase subunit 1 gene

Fig. 2

Geographical distribution Scarcoptes scabiei cox1 subtypes across the Netherlands. cox1, Cytochrome c oxidase subunit 1 gene