Transstadial Transmission from Nymph to Adult of Coxiella burnetii by Naturally Infected Hyalomma lusitanicum.

Julia González,Raquel Martín-Hernández,Marta G González,A Sonia Olmeda,Félix Valcárcel,José M Tercero,María Sánchez

doi:10.3390/pathogens9110884

Julia González, Raquel Martín-Hernández + Show 5 more

Open Access

https://doi.org/10.3390/pathogens9110884

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Journal: Pathogens	Publication Date: Oct 25, 2020
Citations: 10	License type: CC BY 4.0

Affiliation: Centro Regional de Selección y Reproducción Animal

Abstract

Coxiella burnetii (Derrick) Philip, the causative agent of Q fever, is mainly transmitted by aerosols, but ticks can also be a source of infection. Transstadial and transovarial transmission of C. burnetii by Hyalomma lusitanicum (Koch) has been suggested. There is a close relationship between this tick species, wild animals and C. burnetii but the transmission in a natural environment has not been demonstrated. In this study, we collected 80 engorged nymphs of H. lusitanicum from red deer and wild rabbits. They moult to adults under laboratory conditions and we feed them artificially through silicone membranes after a preconditioning period. C. burnetii DNA was tested in ticks, blood and faeces samples using real-time PCR. The pathogen was found in 36.2% of fed adults, demonstrating that transstadial transmission from nymph to adult occurs in nature. The presence of DNA in the 60.0% of blood samples after artificial feeding confirms that adults transmit the bacteria during feeding. Further studies are needed about co-feeding and other possible transmission routes to define the role of this tick species in the cycle of C. burnetii.

Highlights

Coxiella burnetii (Derrick 1939) Philip 1948 is the agent of Q fever, an important zoonotic disease with a broad range of hosts involved [1]
A range of IS1111 copies can be present in the Coxiella-like endosymbionts of ticks [14], the sequencing of the selected positive amplicons confirmed the specific detection of C. burnetti
We detected C. burnetii DNA in 36.2% of newly moulted adult ticks. This prevalence was higher than the prevalence levels reported for H. lusitanicum [7] and other tick species (Duron et al, 2015), usually below 10%

Summary

Introduction

Coxiella burnetii (Derrick 1939) Philip 1948 is the agent of Q fever, an important zoonotic disease with a broad range of hosts involved [1]. In Northern Spain, where Hyalomma spp ticks were not found, C. burnetii DNA was detected in a low rate in ticks [5,6], while a high number of ticks were positive in Central Spain [7,8]. In this latest area, wild animals as red deer (Cervus elaphus L.) and wild rabbits (Oryctolagus cuniculus L.) seem to be more important as a source of infection than domestic animals, and Hyalomma lusitanicum (Koch) ticks are suspected to be the vector of this pathogen in the habitat [7,8,9,10]. Transstadial and transovarial transmission of C. burnetii by this tick species has been suggested, but its vector capacity has yet to be confirmed

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