Proceeding of Veterinary and Animal Science Days 2016, 8th- 10th June, Milan, Italy 

HAF © 2013 

Vol. III, No. 1s  ISSN: 2283-3927 

   

 

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Keywords 

Ixodes ricinus, Midichloria 

mitochondrii, serological 

screening, mammalian hosts, 

marker. 
 

CORRESPONDING AUTHOR 

Valentina Serra 

valentina.serra@unimi.it 

 

JOURNAL HOME PAGE 

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Molecular and serological evidences of 

Midichloria mitochondrii transmission to 

vertebrate hosts during the tick bite. 

V. Serraa*, A. Cafisoa, C. Bazzocchia,b 

a Department of Veterinary Medicine, University of Milan, Via Celoria 10, 
20133 Milan, Italy 

b Joint Research Center for Epidemiology and Molecular Surveillance of 
Infections, University of Milan, 20133 Milan, Italy 

 

Abstract 

The tick Ixodes ricinus is vector of many pathogens important for human and animal health (Parola 

and Raoult, 2001; Socolovschi, 2009). Midichloria mitochondrii (order Rickettsiales; family 

Midichloriaceae) is an endosymbiont present in the salivary glands of 100% of Ixodes ricinus females. 

Two lines of evidence suggest a transmission of M. mitochondrii in mammalians during the tick bite: 1) 

detection of circulating DNA in blood samples of different animal species; 2) seropositivity toward a 

M. mitochondrii protein (FliD) in humans and dogs exposed to tick bite (Mariconti 2012; Bazzocchi 

2013). Here we present serological and molecular results demonstrating the circulation of M. 

mitochondrii also in Capreolus capreolus (the host of choice for adult and nymph stages of I. ricinus), 

confirming that this host is a good subject to study the spread of tick-borne pathogens. 

Based on these results, FliD protein and other M. mitochondrii markers could thus be extremely useful 

to determine the risk of infection by I. ricinus pathogens in given areas, and for investigating the 

epidemiological association of a variety of pathological alterations with this tick. 

Here we show results of the screening of 218 human sera (50 from non endemic areas used as negative 

controls and 168 from subjects exposed to tick bite) collected in different areas of Germany. Results 

showed that 48 out of 168 sera were positive to M. mitochondrii.  

These results have posed the basis for the development of a serological test for investigating the 

exposure of humans and animals to this tick species. 
 

References 

Bazzocchi, C., Mariconti, M., Sassera, D., Rinaldi, L., Martin, E., Cringoli, G., Urbanelli, S., Genchi, C., Bandi, C., Epis,  S., 2013. Molecular and serological evidence 

for the circulation of the tick symbiont Midichloria (Rickettsiales: Midichloriaceae) in different mammalian species. Parasites & Vectors 6, 350–56. 

Mariconti, M., Epis, S., Gaibani, P., Valle, C. dalla, Sassera, D., Tomao, P., Fabbi, M., Castelli, F., Marone, P., Sambri, V ., Bazzocchi, C., Bandi, C., 2012. Humans 

parasitized by the hard tick Ixodes ricinus are seropositive to Midichloria mitochondrii:  is Midichloria a novel pathogen, or just a marker of tick bite? Pathogens 

and Global Health 106, 391–396. 

Parola, P., Raoult, D., 2001. Ticks and tickborne bacterial diseases in humans: an emerging infectious threat. Clinical Infectious Diseases 32, 897–928. 

Socolovschi, C., Mediannikov, O., Raoult, D., Parola, P., 2009. The relationship between spotted fever group Rickettsiae and ixodid ticks. Veterinary Research 

40, 34. 

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