Tick-borne rickettsiae are emerging pathogens belonging to the Spotted Fever Group (SFG). Among them, Rickettsia africae is the most widespread SFG rickettsia in sub-Saharan Africa, where it causes African tick-bite fever; Rickettsia aeschlimannii is characterized by a more heterogeneous geographical distribution and causes symptoms similar to Meditteranean Spotted Fever, symptoms which have been reported so far in African patients or in patients travelling from Africa. In the framework of two research-development projects, in Ethiopia and in Burkina Faso –cofinanced by Regione Piemonte, programme for Decentralised Development Cooperation, and by UNITO_MIUR, local research funds (ex-60%)- we developed a quantitative PCR assay to detect R.aeschlimannii and R.africae OmpA gene. According to our preliminary data, R.aeschlimannii was found to infect Hyalomma rufipes, H.truncatum, and H.impeltatum ticks, randomly collected from nomadic herds (cattle, small ruminants and camels) in villages located in Filtu and Dollo districts, Libaan zone, Somali region of Ethiopia; the overall prevalence was 80% (95% confidence intervals, IC: 56.3-94.3). In Burkina Faso, H.truncatum and H.rufipes were collected from cattle in different provinces throughout the Country, and 36.2% were infected by R.aeschlimannii (95% CI: 22.7-51.5). A very high R.africae prevalence (81.2%; 95%CI: 63.6-92.82) was registered in Amblyomma variegatum ticks from the same animals. This is the first detection of the two pathogens in Burkina Faso and in the Somali Region of Ethiopia. As recorded in other African countries, R.aeschlimannii and R.africae show a high prevalence in Hyalomma and Amblyomma spp. ticks, which are their main vectors and reservoirs. Although the zoonotic potential of these pathogens is known and clinical cases are described quite often in travellers from Africa, further studies are needed to assess the extent of the zoonotic risk and prevalence of infection in livestock keepers, local villagers and population, who have high contact rates with ticks and their vertebrate hosts.

Rickettsia aeschlimannii and Rickettsia africae in ticks collected from livestock in Burkina Faso and Ethiopia

TOMASSONE, Laura;GREGO, Elena;DE MENEGHI, Daniele
2014-01-01

Abstract

Tick-borne rickettsiae are emerging pathogens belonging to the Spotted Fever Group (SFG). Among them, Rickettsia africae is the most widespread SFG rickettsia in sub-Saharan Africa, where it causes African tick-bite fever; Rickettsia aeschlimannii is characterized by a more heterogeneous geographical distribution and causes symptoms similar to Meditteranean Spotted Fever, symptoms which have been reported so far in African patients or in patients travelling from Africa. In the framework of two research-development projects, in Ethiopia and in Burkina Faso –cofinanced by Regione Piemonte, programme for Decentralised Development Cooperation, and by UNITO_MIUR, local research funds (ex-60%)- we developed a quantitative PCR assay to detect R.aeschlimannii and R.africae OmpA gene. According to our preliminary data, R.aeschlimannii was found to infect Hyalomma rufipes, H.truncatum, and H.impeltatum ticks, randomly collected from nomadic herds (cattle, small ruminants and camels) in villages located in Filtu and Dollo districts, Libaan zone, Somali region of Ethiopia; the overall prevalence was 80% (95% confidence intervals, IC: 56.3-94.3). In Burkina Faso, H.truncatum and H.rufipes were collected from cattle in different provinces throughout the Country, and 36.2% were infected by R.aeschlimannii (95% CI: 22.7-51.5). A very high R.africae prevalence (81.2%; 95%CI: 63.6-92.82) was registered in Amblyomma variegatum ticks from the same animals. This is the first detection of the two pathogens in Burkina Faso and in the Somali Region of Ethiopia. As recorded in other African countries, R.aeschlimannii and R.africae show a high prevalence in Hyalomma and Amblyomma spp. ticks, which are their main vectors and reservoirs. Although the zoonotic potential of these pathogens is known and clinical cases are described quite often in travellers from Africa, further studies are needed to assess the extent of the zoonotic risk and prevalence of infection in livestock keepers, local villagers and population, who have high contact rates with ticks and their vertebrate hosts.
2014
Annual Scientific Conference of the European College of Veterinary Public Health (ECVPH), 2014: Evidence-informed decision-making within Veterinary Public Health
Copenhagen
6-10/10/2014
Proceedings of the Annual Scientific Conference and the Annual General Meeting of the European College of Veterinary Public Health, 6-8 October 2014, University of Copenhagen, Copenhagen, Denmark.
Søren Saxmose Nielsen, University of Copenhagen
38
39
http://ecvph.org/meetings-a-events/details/39-ECVPH%20AGM%20?Annual_Scientific_Conference_2014=
Tick-borne rickettsiae; Ethiopia; Burkina Faso; zoonoses
L. Tomassone; E. Grego; E. Chiavassa; H. Adakal; P. Rodighiero; G. Pressi; G. Callà; S. Gebre; B. Zeleke; D. De Meneghi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/158283
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