The enigma of the dog mummy from Ancient Egypt and the origin of ‘Rhipicephalus sanguineus’

Domenico Otranto,Jean-Bernard Huchet,Filipe Dantas-Torres,Alessio Giannelli,Cecile Callou

doi:10.1186/1756-3305-7-2

Abstract

BackgroundTicks belonging to the Rhipicephalus sanguineus group are amongst the most important vectors of pathogenic microorganisms to dogs and humans. However, the taxonomy of this species group is still the subject of debate, especially because there is no type specimen or reliable morphological description for Rhipicephalus sanguineus sensu stricto. Recently, a comprehensive morphological and genetic study on representative tick specimens from Europe, Africa, Americas, and Oceania, revealed the existence of at least four morphologically and genetically distinct species under the name ‘R. sanguineus’ infesting dogs from different countries.MethodsHerein, we examined morphologically tick specimens retrieved on a dog mummy from Ancient Egypt (ca. 1st century – 4th century A.D.). The dog mummy and associated ticks were found during an archaeological expedition conducted in El Deir.ResultsScanning electron micrographs allowed us to assess their identity as belonging to the R. sanguineus group. In addition on the basis of the scutal punctation pattern, spiracular plates, width of dorsal tail of spiracular plates relative to the adjacent festoon, female genital aperture, male adanal plates and accessory shields, these ticks were tentatively identified as Rhipicephalus sp. II (=temperate species).ConclusionsIt can be concluded that R. sanguineus group ticks have infested dogs living in the Mediterranean region since ancient times. This finding represents the oldest record of ticks on any animal species and adds a new piece in the complex puzzle regarding tick parasitism on dogs and humans and their role as vectors of pathogens.

Highlights

Ticks belonging to the Rhipicephalus sanguineus group are amongst the most important vectors of pathogenic microorganisms to dogs and humans
All ticks were unengorged except for one female, and they were identified as belonging to the genus Rhipicephalus, based on the following general characters: eyes present, anal groove posterior to anus, basis capituli hexagonal in shape, palpi short, coxae I deeply cleft, spiracular plates comma-shaped, and male adanal plates and accessory shields present
Females presented the following characters: dorsal scutum shield-shaped, with sinuous posterior margin (Figure 2A); outer edge of cervical grooves clearly defined either by slope or punctations; dorsal tail of spiracular plate narrow (Figure 2B); genital aperture broadly U-shaped (Figure 2C); posteromedian spur on coxa I longer than the posterolateral spur; angles of basis capituli at about mid-length; porose areas small, rounded and well separated (Figure 2D). Based on these key characters, all ticks were identified as belonging to the R. sanguineus group

Summary

Introduction

Ticks belonging to the Rhipicephalus sanguineus group are amongst the most important vectors of pathogenic microorganisms to dogs and humans. The taxonomy of this species group is still the subject of debate, especially because there is no type specimen or reliable morphological description for Rhipicephalus sanguineus sensu stricto. A comprehensive morphological and genetic study on representative tick specimens from Europe, Africa, Americas, and Oceania, revealed the existence of at least four morphologically and genetically distinct species under the name ‘R. sanguineus’ infesting dogs from different countries. A comprehensive study was undertaken on representative tick specimens belonging to the R. sanguineus group from 17 countries in Europe, Africa, Americas, and Oceania [4]. In the absence of a consensus on the identity of R. sanguineus sensu stricto, the taxonomical status and actual distribution of these species remains enigmatic

Methods

Results

Conclusion