Rickettsia africae, Western Africa

New insights into the systematics of the afrotropical Amblyomma marmoreum complex (Acari: Ixodidae) and the genome of a novel Rickettsia africae strain using morphological and metagenomic approaches

The Amblyomma marmoreum complex includes afrotropical species, such as Amblyomma sparsum, a three-host tick that parasitizes reptiles, birds, and mammals, and is a recognized vector of Ehrlichia ruminantium. However, the lack of morphological, genetic and ecological data on A. sparsum has caused considerable confusion in its identification. In this study, we used microscopy and metagenomic approaches to analyze A. sparsum ticks collected from a puff adder snake (Bitis arietans) in southwest Senegal (an endemic rickettsioses area) in order to supplement previous morphological descriptions, provide novel genomic data for the A. marmoreum complex, and describe the genome of a novel spotted fever group Rickettsia strain. Based on stereoscope and scanning electron microscopy (SEM) morphological evaluations, we provide high-quality images and new insights about punctation and enameling in the adult male of A. sparsum to facilitate identification for future studies. The metagenomic approach allowed us assembly the complete mitochondrial genome of A. sparsum, as well as the nearly entire chromosome and complete plasmid sequences of a novel Rickettsia africae strain. Phylogenomic analyses demonstrated a close relationship between A. sparsum and Amblyomma nuttalli for the first time and confirmed the position of A. sparsum within the A. marmoreum complex. Our results provide new insights into the systematics of A. sparsum and A. marmoreum complex, as well as the genetic diversity of R. africae in the Afrotropical region. Future studies should consider the possibility that A. sparsum may be a vector for R. africae.

First Molecular Identification of Rickettsia aeschlimannii and Rickettsia africae in Ticks from Ghana

The threats from vector-borne pathogens transmitted by ticks place people (including deployed troops) at increased risk for infection, frequently contributing to undifferentiated febrile illness syndromes. Wild and domesticated animals are critical to the transmission cycle of many tick-borne diseases. Livestock can be infected by ticks, and serve as hosts to tick-borne diseases such as rickettsiosis. Thus, it is necessary to identify the tick species and determine their potential to transmit pathogens. A total of 1,493 adult ticks from three genera-Amblyomma, Hyalomma, and Rhipicephalus-were identified using available morphological keys and were pooled (n = 541) by sex and species. Rickettsia species were detected in 308 of 541 (56.9%) pools by genus-specific quantitative polymerase chain reaction assay (Rick17b). Furthermore, sequencing of the outer membrane protein A and B genes (ompA and ompB) of random samples of Rickettsia-positive samples led to the identification of Rickettsia aeschlimannii and Rickettsia africae with most R. africae DNA (80.2%) detected in pools of Amblyomma variegatum. We report the first molecular detection and identification of the rickettsial pathogens R. africae and R. aeschlimannii in ticks from Ghana. Our findings suggest there is a need to use control measures to prevent infections from occurring among human populations in endemic areas in Ghana. This study underscores the importance of determining which vector-borne pathogens are in circulation in Ghana. Further clinical and prevalence studies are needed to understand more comprehensively the clinical impact of these rickettsial pathogens contributing to human disease and morbidity in Ghana.

Low genetic diversity and population structuring of Amblyomma hebraeum and Rickettsia africae from coastal and inland regions in the Eastern Cape Province of South Africa

Amblyomma hebraeum is the main vector of Rickettsia africae, the causative agent of African tick bite fever in southern Africa. Because pathogen dispersal is known to be influenced by tick adaptations to climate or host species, this study aimed to analyse the genetic diversity of A. hebraeum and R. africae infection of ticks collected from cattle in the Eastern Cape province of South Africa. DNA was extracted, amplified, and sequenced for the COI and ITS2 markers from A. hebraeum samples and the 17 kDa and ompA genes for rickettsial detection. Between six and ten haplotypes were identified from 40 COI and 31 ITS2 sequences; however, no population structuring was observed among sites (ΦST = 0.22, p < 0.05). All A. hebraeum isolates clustered with southern Africa GenBank isolates. Rickettsia africae was detected in 46.92% (95% CI = 41%-53%, n = 260) of ticks. All R. africae isolates clustered with strain PELE and Chucks, which were reported previously from South Africa. These results confirm that A. hebraeum populations are undergoing a recent population expansion driven by cattle movement, facilitating local and long dispersal events across the Eastern Cape province.

Molecular and MALDI-TOF MS characterisation of Hyalomma aegyptium ticks collected from turtles and their associated microorganisms in Algeria

The identification of ticks and their associated pathogens is important for knowledge on tick-borne diseases. The objective of this study was to use morphological, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and/or molecular biology tools to identify ticks collected from turtles in north-eastern Algeria, as well as to investigate the microorganisms associated with these ticks. A total of 471 adult ticks were collected and identified morphologically as Hyalomma aegyptium, of which 248 (52.7%) were female and 223 (47.3%) were male. amongst them, 230 specimens were randomly selected for molecular and MALDI-TOF MS analysis. Molecular biology confirmed that our ticks were Hy. aegyptium. MALDI-TOF MS analysis revealed that 100% of the spectra were of excellent quality. Four spectra were selected to update our own database MALDI-TOF MS arthropod. The blind test of the 226 remaining spectra showed that all ticks were correctly identified, with scores ranging from 1.774 to 2.655 with a mean of 2.271 ± 0.16 of which, 223 (98.6%) had log score value (LSV)>1.8. Molecular biology screening showed that the ticks carried the DNA of Borrelia turcica, Rickettsia africae, Rickettsia aeschlimannii, Rickettsia sibirica mongolitimonae and with the Anaplasmataceae were close to a potentially new, undescribed Ehrlichia sp. This study confirms that MALDI-TOF MS is a reliable tool for the identification of ticks and that ticks collected from turtles in Algeria are carriers of several species of microorganisms which may be responsible for diseases in humans and animals.

Morphological, molecular and MALDI-TOF MS identification of ticks and tick-associated pathogens in Vietnam

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising and reliable tool for arthropod identification, including the identification of alcohol-preserved ticks based on extracted leg protein spectra. In this study, the legs of 361 ticks collected in Vietnam, including 251 Rhiphicephalus sanguineus s.l, 99 Rhipicephalus (Boophilus) microplus, two Amblyomma varanensis, seven Dermacentor auratus, one Dermacentor compactus and one Amblyomma sp. were submitted for MALDI-TOF MS analyses. Spectral analysis showed intra-species reproducibility and inter-species specificity and the spectra of 329 (91%) specimens were of excellent quality. The blind test of 310 spectra remaining after updating the database with 19 spectra revealed that all were correctly identified with log score values (LSV) ranging from 1.7 to 2.396 with a mean of 1.982 ± 0.142 and a median of 1.971. The DNA of several microorganisms including Anaplasma platys, Anaplasma phagocytophilum, Anaplasma marginale, Ehrlichia rustica, Babesia vogeli, Theileria sinensis, and Theileria orientalis were detected in 25 ticks. Co-infection by A. phagocytophilum and T. sinensis was found in one Rh. (B) microplus.

Tick species from cattle in the Adama Region of Ethiopia and pathogens detected

Ticks will diminish productivity among farm animals and transmit zoonotic diseases. We conducted a study to identify tick species infesting slaughter bulls from Adama City and to screen them for tick-borne pathogens. In 2016, 291 ticks were collected from 37 bulls in Adama, which were ready for slaughter. Ticks were identified morphologically. Total genomic DNA was extracted from ticks and used to test for Rickettsia spp. with real-time PCR. Species identification was done by phylogenetic analysis using sequencing that targeted the 23S-5S intergenic spacer region and ompA genes. Four tick species from two genera, Amblyomma and Rhipicephalus, were identified. Amblyomma cohaerens was the dominant species (n = 241, 82.8%), followed by Amblyomma variegatum (n = 22, 7.5%), Rhipicephalus pulchellus (n = 19, 6.5%), and Rhipicephalus decoloratus (n = 9, 3.0%). Among all ticks, 32 (11%) were positive for Rickettsia spp. and 15 (5.2%) of these were identified as R. africae comprising at least two genetic clades, occurring in A. variegatum (n = 10) and A. cohaerens (n = 5). The remainder of Rickettsia-positive samples could not be amplified due to low DNA yield. Furthermore, another 15 (5.2%) samples carried other pathogenic bacteria: Ehrlichia ruminantium (n = 9; 3.1%) in A. cohaerens, Ehrlichia sp. (n = 3; 1%) in Rh. pulchellus and A. cohaerens, Anaplasma sp. (n = 1; 0.5%) in A. cohaerens, and Neoehrlichia mikurensis (n = 2; 0.7%) in A. cohaerens. All ticks were negative for Bartonella spp., Babesia spp., Theileria spp., and Hepatozoon spp. We reported for the first time E. ruminatium, N. mikurensis, Ehrlichia sp., and Anaplasma sp. in A. cohaerens. Medically and veterinarily important pathogens were mostly detected from A. variegatum and A. cohaerens. These data are relevant for a One-health approach for monitoring and prevention of tick-borne disease transmission.

New records of bacteria in different species of fleas from France and Spain

In this study, we assessed the presence of vector-borne microorganisms in different species of fleas collected from different hosts in diverse areas of South-Western Europe by molecular methods. A total of 319 fleas belonging to eight different species was tested for the presence of eight microorganisms. Wolbachia spp. endosymbionts were detected in Ctenocephalides felis, Pulex irritans, Archaeopsylla erinacei and Ctenophthalmus baeticus boisseauorum specimens. Rickettsia felis, an emerging pathogen, was detected in C. felis, A. erinacei and Ct. b. boisseauorum. Rickettsia typhi, the agent of murine typhus was detected for the first time in A. erinacei and Mycobacterium spp. were detected for the first time in fleas (C. felis, P. irritans and A. erinacei). Lastly, five different species of Bartonella were detected in fleas' DNA in this study, including a possible new bacterium belonging to this genus. With this study, we updated the knowledge of the flea-borne bacteria present in the South-West of Europe reinforcing the idea about the necessity to expand and increase the current knowledge on flea-borne pathogens.

Molecular detection and characterisation of protozoan and rickettsial pathogens in ticks from cattle in the pastoral area of Karamoja, Uganda

Ticks and tick-borne diseases (TBDs) significantly affect cattle production and the livelihoods of communities in pastoralist areas. Data on protozoan and rickettsial pathogens in ticks infesting cattle in Uganda is scanty; while it is an indicator of the likelihood of disease transmission and occurrence. A cross-sectional study was conducted amongst cattle in the Karamoja Region, northeastern Uganda, from July through September 2017, to determine the tick species diversity, identify protozoan and rickettsial pathogens in the ticks, and characterise pathogenic species by sequence and phylogenetic analyses. About 50 % of the ticks detected from each predilection site on each animal were collected from 100 purposively-selected cattle from 20 randomly-selected herds. Twelve tick species belonging to the genera Amblyomma, Rhipicephalus and Hyalomma were identified, the most abundant being Amblyomma lepidum (93.9 %), followed by Amblyomma variegatum (2.0 %) and Rhipicephalus evertsi evertsi (1.0 %). Tick species that have not been reported in recent studies amongst cattle in Uganda were found, namely Rhipicephalus pravus, Rhipicephalus praetextatus and Rhipicephalus turanicus. The ticks were grouped into 40 pools, by species and location, and the reverse line blot (RLB) hybridisation assay was used to detect pathogens from the ticks. The most frequently detected tick-borne parasites were Theileria mutans, Theileria velifera and Theileria parva, each observed in 25 % (10/40) of the tick pools. Tick-borne pathogens, namely Babesia rossi, Babesia microti and Theileria sp. (sable) that are not common to, or not known to infect, cattle were identified from ticks. The gene encoding Ehrlichia ruminantium pCS20 region, the Ehrlichia and Anaplasma 16S rRNA gene, and T. parva p67 sporozoite antigen gene were amplified, cloned and sequenced. Seven novel E. ruminantium pCS20 variants were identified, and these grouped into two separate clusters with sequences from other parts of Africa and Asia. The T. parva p67 sequences were of the allele type 1, and parasites possessing this allele type are commonly associated with East Coast fever in eastern Africa. Analysis of the Ehrlichia and Anaplasma 16S rRNA gene sequences showed that they were closely related to Rickettsia africae and to a new Ehrlichia species variant recently found in China. Our R. africae 16S rRNA sequences grouped with R. africae isolates from Nigeria, Egypt and Benin. The information on tick species diversity and pathogens in the various tick species provides an indicator of potential transmission amongst cattle populations, and to humans, and can be useful to estimate disease risk and in control strategies.

Multi-country investigation of the diversity and associated microorganisms isolated from tick species from domestic animals, wildlife and vegetation in selected african countries

In many areas of Africa, recent studies highlighted the great impact of ticks on animal and human health throughout the continent. On the other hand, very limited information on the bacterial endosymbionts of the African ticks and their pattern of co-infections with other bacteria are found in literature, notwithstanding their pivotal role in tick survival and vector efficiency. Thus, we investigated the distribution of selected pathogenic and symbiotic bacteria in hard ticks collected from wild, domestic animals and from vegetation in various ecological zones in Africa and their co-occurrence in the same tick host. Overall, 339 hard ticks were morphologically identified as belonging to the genera Amblyomma, Dermacentor, Hyalomma, Haemaphysalis, Ixodes and Rhipicephalus. Molecular screening provided information on pathogens circulation in Africa, detecting spotted fever group rickettsiae, Anaplasma spp., Ehrlichia ruminantium, Borrelia garinii, Babesia spp., Theileria spp. and Coxiella burnetii. Furthermore, our work provides insights on the African scenario of tick-symbiont associations, revealing the presence of Coxiella, Francisella and Midichloria across multiple tick populations. Coxiella endosymbionts were the most prevalent microorganisms, and that with the broadest spectrum of hosts, being detected in 16 tick species. Francisella was highly prevalent among the Hyalomma species tested and correlated negatively with the presence of Coxiella, showing a potential competitive interaction. Interestingly, we detected a positive association of Francisella with Rickettsia in specimens of Hy. rufipes, suggesting a synergistic interaction between them. Finally, Midichloria was the most prevalent symbiont in Rhipicephalus sanguineus sensu lato from Egypt.

Tick-borne pathogens, including Crimean-Congo haemorrhagic fever virus, at livestock markets and slaughterhouses in western Kenya

Vectors of emerging infectious diseases have expanded their distributional ranges in recent decades due to increased global travel, trade connectivity and climate change. Transboundary range shifts, arising from the continuous movement of humans and livestock across borders, are of particular disease control concern. Several tick-borne diseases are known to circulate between eastern Uganda and the western counties of Kenya, with one fatal case of Crimean-Congo haemorrhagic fever (CCHF) reported in 2000 in western Kenya. Recent reports of CCHF in Uganda have highlighted the risk of cross-border disease translocation and the importance of establishing inter-epidemic, early warning systems to detect possible outbreaks. We therefore carried out surveillance of tick-borne zoonotic pathogens at livestock markets and slaughterhouses in three counties of western Kenya that neighbour Uganda. Ticks and other ectoparasites were collected from livestock and identified using morphological keys. The two most frequently sampled tick species were Rhipicephalus decoloratus (35%) and Amblyomma variegatum (30%); Ctenocephalides felis fleas and Haematopinus suis lice were also present. In total, 486 ticks, lice and fleas were screened for pathogen presence using established molecular workflows incorporating high-resolution melting analysis and identified through sequencing of PCR products. We detected CCHF virus in Rh. decoloratus and Rhipicephalus sp. cattle ticks, and 82 of 96 pools of Am. variegatum were positive for Rickettsia africae. Apicomplexan protozoa and bacteria of veterinary importance, such as Theileria parva, Babesia bigemina and Anaplasma marginale, were primarily detected in rhipicephaline ticks. Our findings show the presence of several pathogens of public health and veterinary importance in ticks from livestock at livestock markets and slaughterhouses in western Kenya. Confirmation of CCHF virus, a Nairovirus that causes haemorrhagic fever with a high case fatality rate in humans, highlights the risk of under-diagnosed zoonotic diseases and calls for continuous surveillance and the development of preventative measures.

Molecular identification and characterization of Rickettsia spp. and other tick-borne pathogens in cattle and their ticks from Huambo, Angola

Ticks are one of the most common vectors of a broad variety of pathogenic agents that significantly affects cattle production causing reduced productivity and important economic losses, while simultaneously having an impact on human health due to the zoonotic risk. In much of the territory of Angola urban population has grown rapidly in recent decades, sharing today close contact with large farms that are generally owned by city residents, providing the ideal conditions for vector-borne pathogens (VBP) transmission between animals and humans. Here we studied the occurrence of Rickettsia, Anaplasma, Ehrlichia, Babesia and Theileria in domestic cattle (n = 98) from Huambo, Angola, and their ticks (n = 116) to obtain a more detailed knowledge into the spectrum of tick-borne agents circulating in this population. We morphologically identified Amblyomma variegatum, Rhipicephalus decoloratus and R. evertsi mimeticus ticks, further confirmed by molecular analysis of the 12S rDNA and 16S rDNA genes. Although none of the bovine blood showed to be positive for R. africae by the ompB, ompA and gltA assays, five ticks showed to be positive for R. africae by the ompB, ompA and the gltA PCRs. Two 18S rRNA sequences were retrieved from bovine blood and one sequence from A. variegatum tick, showing 100% identity with Theileria mutans. By using a PCR targeting the 16S rRNA gene of Anaplama spp. we have also obtained six bovine blood samples showing 99-100 % nucleotide sequence identity with A. capra, two showing 98 % nucleotide sequence identity with A. phagocytophilum and three showing 98-100 % nucleotide sequence identity with A. platys. None of the ticks were positive. The present study shows the presence of a wide range of vector-borne diseases in domestic cattle and their ticks in Huambo province, Angola. Given the lack of both animal and human health infrastructures in this rural region, swift diagnosis and treatment is hampered which could produce a more severe impact on health.

Zoonotic Parasites of Reptiles: A Crawling Threat

Reptiles are reservoirs of a wide range of pathogens, including many protozoa, helminths, pentastomids, and arthropod parasitic species, some of which may be of public health concern. In this review we discuss the zoonotic risks associated with human–reptile interactions. Increased urbanization and introduction of exotic species of reptile may act as drivers for the transmission of zoonotic parasites through the environment. In addition, being a part of human diet, reptiles can be a source of life-threatening parasitoses, such as pentastomiasis or sparganosis. Finally, reptiles kept as pets may represent a risk to owners given the possibility of parasites transmitted by direct contact or fecal contamination. Awareness of reptile-borne zoonotic parasitoses is important to advocate control, prevention, and surveillance of these neglected diseases.

Species of protozoa, helminths, pentastomids, and arthropod vectors exploit reptiles as definitive or paratenic hosts, which may represent a public health concern.

The zoonotic risk is associated with human–reptile interactions and includes environmental contamination, reptile consumption, or keeping reptiles as pets.

Exotic reptile species may introduce new zoonotic parasites in a previously nonendemic region.

Pentastomiasis and sparganosis are life-threatening food-borne parasitoses.

In our households, if precautions are not taken, reptiles may transmit zoonotic parasites by direct contact or fecal contamination.

Trained veterinarians, physicians, and public health officials are important to advocate for proper diagnostics, parasite identification and treatment, as well as for surveillance strategies and food inspection in areas where reptiles are consumed.

The Trick of the Hedgehog: Case Report and Short Review About Archaeopsylla erinacei (Siphonaptera: Pulicidae) in Human Health

Fleas are ectoparasites of various animals, including Homo sapiens Linnaeus, 1758 (Primates: Hominidae). Among the species relevant to the human health field, either due to their dermatopathological potential or because of their role as vectors of microorganisms responsible for infectious diseases, such as plague or murine typhus, are the human flea, oriental rat flea, closely related cat and dog fleas, and chigoe flea. However, other species can accidentally infest humans. We have herein reported two unusual cases of humans infested and bitten by Archaeopsylla erinacei, the hedgehog flea. This species has been identified using stereomicroscopy, on the base of key characteristics. Furthermore, a brief literature review has revealed that hedgehog fleas could carry human-infectious agents, such as Rickettsia felis Bouyer et al. 2001 (Rickettsiales: Rickettsiaceae) or Bartonella henselae Regnery et al.1992 (Rhizobiales: Bartonellaceae). Using molecular biology, we thus tested nine A. erinacei specimens taken from these patients, for several bacteria species commonly associated with hematophagous arthropods, implicated in human pathology. However, all our samples were proven negative. The role of A. erinacei in human epidemiology has never been evaluated to date. This report sought to remind us that these fleas can be accidental parasites in humans. In addition, recent findings pertaining to bacteria of medical interest that are present in these insects should be brought to the fore, given that the question of their role as vectors in human infections remains unanswered and deserves further investigation.

Molecular epidemiology and phylogeny of spotted fever group Rickettsia in camels (Camelus dromedarius) and their infesting ticks from Tunisia

Rickettsia species are adapted to a wide range of specific animal hosts. Camels (Camelus dromedarius) have been identified as a carrier of various zoonotic pathogens and became a focus of growing public health interest. This study reported the occurrence of rickettsial infection in camels and infesting ticks from five Tunisian governorates. Based on ompB PCR, eight out of 293 camels (2.7%) were found to be infected with Rickettsia spp. Furthermore, 13 tick specimens of Hyalomma impeltatum (10.4%) and 9 of H. dromedarii (8.0%) harboured DNA of Rickettsia bacteria with an overall prevalence rate of 9.2% (22/237). Molecular prevalence of Rickettsia infection varied significantly according to tick infestation for camels and among tick genders. Five rickettsial species, showing a potential public health interest, were revealed by sequencing. Based on ompB partial sequences, five species were identified corresponding to R. aeschlimannii, R. monacensis, R. helvetica and R. massiliae in camels and to R. africae, R. aeschlimannii, R. monacensis and R. helvetica in ticks. Based on ompA typing, three species were revealed corresponding to R. africae and R. monacensis in camels and to R. africae, R. aeschlimannii and R. monacensis in ticks. This is the first report consolidating the hypothesis that camels may serve as potential hosts for Rickettsia spp. and Hyalomma spp. ticks as possible vectors in arid and Saharan areas of Tunisia. The present data highlight the importance of preventive measures and survey that must be implemented in camel herds in order to limit the spread of these vector-borne bacteria to animals and humans.

Developing Research in Infectious and Tropical Diseases in Africa: The Paradigm of Senegal

Infectious diseases represent one of the greatest potential barriers to achievement of the third Sustainable Development Goals in African countries and around the world because they continue to pose major public health challenges. The surveillance of infectious diseases has recently assumed greater importance in most African countries, both because of the emergence of infectious diseases and because strains of pathogens that cause tuberculosis, malaria, cholera, dysentery, and pneumonia have developed resistance to common and inexpensive antimicrobial drugs. However, data on the pathogen-specific causes of infectious diseases are limited. Developing research in infectious and tropical diseases in Africa is urgently needed to better describe the distribution of pathogen-borne diseases and to know which pathogens actually cause fever. This research is critical for guiding treatment and policies in Africa. More effective diagnostics are also needed for these diseases, which often are misdiagnosed or diagnosed too late. A comprehensive review of this type of research is presented here.

A New Collection of Amblyomma parvitarsum (Acari: Ixodidae) in Peru, With Description of a Gynandromorph and Report of Rickettsia Detection

Adult stages of Amblyomma parvitarsum Neumann parasitize wild and domestic camelids of the genera Lama and Vicugna in highlands of Andean Plateau and Patagonia. Within the Peruvian Andes, few reports have documented this tick-host association, and although reported in Chile and Argentina, Rickettsia-infected A. parvitarsum remains undocumented for this country. Here we report a new collection of A. parvitarsum from Peru, the finding of the first gynandromorph for the species and high prevalence of Rickettsia in adult stages.

Tick-, Flea-, and Louse-Borne Diseases of Public Health and Veterinary Significance in Nigeria

Mosquito-borne diseases are common high-impact diseases in tropical and subtropical areas. However, other non-mosquito vector-borne pathogens (VBPs) may share their geographic distribution, seasonality, and clinical manifestations, thereby contributing their share to the morbidity and mortality caused by febrile illnesses in these regions. The purpose of this work was to collect and review existing information and identify knowledge gaps about tick, flea-, and louse-borne diseases of veterinary and public health significance in Nigeria. Full-length articles about VBPs were reviewed and relevant information about the vectors, their hosts, geographic distribution, seasonality, and association(s) with human or veterinary diseases was extracted. Specific laboratory tools used for detection and identification of VBPs in Nigeria were also identified. A total of 62 original publications were examined. Substantial information about the prevalence and impacts of ticks and fleas on pet and service dogs (18 articles), and livestock animals (23 articles) were available; however, information about their association with and potential for causing human illnesses was largely absent despite the zoonotic nature of many of these peri-domestic veterinary diseases. Recent publications that employed molecular methods of detection demonstrated the occurrence of several classic (Ehrlichia canis, Rickettsia africae, Bartonella sp.) and emerging human pathogens (R. aeschlimannii, Neoehrlichia mikurensis) in ticks and fleas. However, information about other pathogens often found in association with ticks (R. conorii) and fleas (R. typhi, R. felis) across the African continent was lacking. Records of louse-borne epidemic typhus in Nigeria date to 1947; however, its current status is not known. This review provides an essential baseline summary of the current knowledge in Nigeria of non-mosquito VBPs, and should stimulate improvements in the surveillance of the veterinary and human diseases they cause in Nigeria. Due to increasing recognition of these diseases in other African countries, veterinary and public health professionals in Nigeria should expand the list of possible diseases considered in patients presenting with fever of unknown etiology.

Molecular detection of pathogens in ticks infesting cattle in Nampula province, Mozambique

Ticks are ectoparasites that can act as vectors of a large number of pathogens in wild and domestic animals, pets, and occasionally humans. The global threat of emerging or re-emerging tick-borne diseases supports the need for research focused in the zoonotic transmission, especially in countries like Mozambique where rural populations are in close contact with domestic animals. The present study aims to: (1) identify tick species infesting cattle from Monapo and Nacala Porto, districts of Nampula province, Mozambique; and (2) investigate the presence of pathogens in the collected ticks. A total of 646 ticks were collected from cattle and morphologically identified as Amblyomma variegatum, Rhipicephalus microplus, and R. evertsi evertsi. For convenience, 72 A. variegatum and 15 R. microplus from Monapo, and 30 A. variegatum from Nacala Porto were screened for the presence of the selected pathogens: Rickettsia spp. (A. variegatum), and Babesia/Theileria spp. and Anaplasma/Ehrlichia spp. (R. microplus). Rickettsia africae was detected in four of the 72 A. variegatum collected in Monapo (5.6%). Additionally, one R. microplus tick (6.7%) was positive for Theileria velifera, one positive for Colpodella spp., one positive for Candidatus Midichloria mitochondrii, and another one positive for Anaplasma ovis. Using the present approach, no microorganisms were detected in tick samples from Nacala Porto. These findings expand our knowledge about the repertoire of tick-borne microorganisms in ticks in Nampula province, Mozambique.

Molecular and MALDI-TOF identification of ticks and tick-associated bacteria in Mali

Ticks are considered the second vector of human and animal diseases after mosquitoes. Therefore, identification of ticks and associated pathogens is an important step in the management of these vectors. In recent years, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising method for the identification of arthropods including ticks. The objective of this study was to improve the conditions for the preparation of tick samples for their identification by MALDI-TOF MS from field-collected ethanol-stored Malian samples and to evaluate the capacity of this technology to distinguish infected and uninfected ticks. A total of 1,333 ticks were collected from mammals in three distinct sites from Mali. Morphological identification allowed classification of ticks into 6 species including Amblyomma variegatum, Hyalomma truncatum, Hyalomma marginatum rufipes, Rhipicephalus (Boophilus) microplus, Rhipicephalus evertsi evertsi and Rhipicephalus sanguineus sl. Among those, 471 ticks were randomly selected for molecular and proteomic analyses. Tick legs submitted to MALDI-TOF MS revealed a concordant morpho/molecular identification of 99.6%. The inclusion in our MALDI-TOF MS arthropod database of MS reference spectra from ethanol-preserved tick leg specimens was required to obtain reliable identification. When tested by molecular tools, 76.6%, 37.6%, 20.8% and 1.1% of the specimens tested were positive for Rickettsia spp., Coxiella burnetii, Anaplasmataceae and Borrelia spp., respectively. These results support the fact that MALDI-TOF is a reliable tool for the identification of ticks conserved in alcohol and enhances knowledge about the diversity of tick species and pathogens transmitted by ticks circulating in Mali.

Anaplasma, Ehrlichia and rickettsial pathogens in ixodid ticks infesting cattle and sheep in western Oromia, Ethiopia

Although ticks are widely distributed in all agro-ecological zones of Ethiopia, information on tick-borne pathogens is scarce. This study was conducted to determine the presence of Anaplasma spp., Ehrlichia spp., and Rickettsia spp. in Rhipicephalus evertsi and Rhipicephalus (Boophilus) decoloratus collected from cattle and sheep at Bako, western Oromia, Ethiopia, using polymerase chain reaction and sequencing. Anaplasma ovis and Anaplasma spp., Ehrlichia ruminantium and Ehrlichia spp. were detected in Rh. decoloratus, whereas only A. ovis was detected in Rh. evertsi. Both tick species were found to harbor DNA belonging to Rickettsia spp., and Rickettsia africae. Our findings highlight the risk of infection of animals and humans with these zoonotic tick-borne bacteria in Ethiopia.

SPOTTED FEVER GROUP RICKETTSIA RETINITIS IN A TRAVELER TO AFRICA

PURPOSE

To describe a case of rickettsial retinitis in a traveler returning from Africa.

METHOD

Case description.

RESULTS

A 67-year-old woman returning from an excursion in the jungles of Africa presented with a 2-day history of floaters and decreased vision in the right eye. In the two preceding weeks, she had experienced fever, malaise, a black eschar on the right elbow, and a rash on her extremities. Examination revealed panuveitis with a solitary, white retinal lesion adjacent to a retinal vessel in the posterior pole of each eye. Extensive diagnostic workup revealed a positive serology for rickettsial antibodies. Her treatment consisted of a course of oral doxycycline.

CONCLUSION

Rickettsial retinitis is an emerging ocular infection in several endemic areas. This case description constitutes the first report of spotted fever group rickettsial retinitis in a traveler to Africa.

High prevalence of Rickettsia africae variants in Amblyomma variegatum ticks from domestic mammals in rural western Kenya: implications for human health

Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya. Of the 100 serum specimens tested from each species of domestic ruminant 43% of goats, 23% of sheep, and 1% of cattle had immunoglobulin G (IgG) antibodies to the SFG rickettsiae. None of these sera were positive for IgG against typhus group rickettsiae. We detected Rickettsia africae-genotype DNA in 92.6% of adult Amblyomma variegatum ticks collected from domestic ruminants, but found no evidence of the pathogen in blood specimens from cattle, goats, or sheep. Sequencing of a subset of 21 rickettsia-positive ticks revealed R. africae variants in 95.2% (20/21) of ticks tested. Our findings show a high prevalence of R. africae variants in A. variegatum ticks in western Kenya, which may represent a low disease risk for humans. This may provide a possible explanation for the lack of African tick-bite fever cases among febrile patients in Kenya.

Multiple Pathogens Including Potential New Species in Tick Vectors in Côte d'Ivoire

BACKGROUND

Our study aimed to assess the presence of different pathogens in ticks collected in two regions in Côte d'Ivoire.

METHODOLOGY/PRINCIPAL FINDINGS

Real-time PCR and standard PCR assays coupled to sequencing were used. Three hundred and seventy eight (378) ticks (170 Amblyomma variegatum, 161 Rhipicepalus microplus, 3 Rhipicephalus senegalensis, 27 Hyalomma truncatum, 16 Hyalomma marginatum rufipes, and 1 Hyalomma impressum) were identified and analyzed. We identified as pathogenic bacteria, Rickettsia africae in Am. variegatum (90%), Rh. microplus (10%) and Hyalomma spp. (9%), Rickettsia aeschlimannii in Hyalomma spp. (23%), Rickettsia massiliae in Rh. senegalensis (33%) as well as Coxiella burnetii in 0.2%, Borrelia sp. in 0.2%, Anaplasma centrale in 0.2%, Anaplasma marginale in 0.5%, and Ehrlichia ruminantium in 0.5% of all ticks. Potential new species of Borrelia, Anaplasma, and Wolbachia were detected. Candidatus Borrelia africana and Candidatus Borrelia ivorensis (detected in three ticks) are phylogenetically distant from both the relapsing fever group and Lyme disease group borreliae; both were detected in Am. variegatum. Four new genotypes of bacteria from the Anaplasmataceae family were identified, namely Candidatus Anaplasma ivorensis (detected in three ticks), Candidatus Ehrlichia urmitei (in nine ticks), Candidatus Ehrlichia rustica (in four ticks), and Candidatus Wolbachia ivorensis (in one tick).

CONCLUSIONS/SIGNIFICANCE

For the first time, we demonstrate the presence of different pathogens such as R. aeschlimannii, C. burnetii, Borrelia sp., A. centrale, A. marginale, and E. ruminantium in ticks in Côte d'Ivoire as well as potential new species of unknown pathogenicity.

Rickettsia spp. in seabird ticks from western Indian Ocean islands, 2011-2012

We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances.

Spotted fever group rickettsiae in ixodid ticks in Oromia, Ethiopia

In Ethiopia, information on the transmission of human zoonotic pathogens through ixodid ticks remains scarce. To address the occurrence and molecular identity of spotted fever group rickettsiae using molecular tools, a total of 767 ixodid ticks belonging to thirteen different species were collected from domestic animals from September 2011 to March 2014. Rickettsia africae DNA was detected in 30.2% (16/53) Amblyommma variegatum, 28.6% (12/42) Am. gemma, 0.8% (1/119) Am. cohaerens, 18.2% (4/22) Amblyomma larvae, 6.7% (2/60) Amblyomma nymphs, 0.7% (1/139) Rhipicephalus (Boophilus) decoloratus and 25% (1/4) nymphs of Rh. (Bo.) decoloratus. A markedly low prevalence of R. africae was recorded in both Am. cohaerens and Rh. (Bo.) decoloratus (p<0.0001) compared with that in Am. variegatum and Am. gemma. The prevalence of R. africae was markedly low in the western districts (Gachi and Abdela) (p<0.0001); however, the prevalence of R. africae was relatively high in the central (Ada'a, Wolmara and Arsi) and eastern (Arero, Moyale and Yabelo) districts, where Am. variegatum and Am. gemma were predominantly associated with R. africae, respectively. R. aeschlimannii DNA was detected in 45.4% (5/11) Hyalomma marginatum rufipes and 2.2% (1/46) Hy. truncatum. Moreover, the first report of R. massiliae DNA in 1.9% (1/52) Rhipicephalus praetextatus ticks in Ethiopia is presented herein. Altogether, these results suggest that the transmission of spotted fever group rickettsiae through ixodid ticks is a potential risk for human health in different parts of Ethiopia. Clinicians in this country should consider these pathogens as a potential cause of febrile illness in patients.

Looking in ticks for human bacterial pathogens

Ticks are considered to be second worldwide to mosquitoes as vectors of human diseases and the most important vectors of disease-causing pathogens in domestic and wild animals. A number of emerging tick-borne pathogens are already discovered; however, the proportion of undiagnosed infectious diseases, especially in tropical regions, may suggest that there are still more pathogens associated with ticks. Moreover, the identification of bacteria associated with ticks may provide new tool for the control of ticks and tick-borne diseases. Described here molecular methods of screening of ticks, extensive use of modern culturomics approach, newly developed artificial media and different cell line cultures may significantly improve our knowledge about the ticks as the agents of human and animal pathology.

Molecular identification of pathogenic bacteria in eschars from acute febrile patients, Senegal

Fever caused by Rickettsia felis was recently shown to play an important role in infectious diseases morbidity in sub-Saharan Africa. We collected 68 cotton swabs from fever-associated eschars in four different regions of Senegal. In 5 of 68 eschar samples (7.4%), we have identified DNA from R. felis. In 49 of 68 eschar samples (72.1%), we have identified DNA from Staphylococcus aureus. In 35 of 68 eschar samples (51.5%), we have identified DNA from Streptococcus pyogenes, and in 4 of 68 eschar samples (5.9%), we have identified DNA from Streptococcus pneumoniae. In 34 cases, S. aureus was found together with S. pyogenes. DNA from R. felis was also found in swabs from the skin of the healthy Senegalese villagers (3 of 60; 5%) but not French urbanites. The presence of S. aureus and S. pyogenes was significantly associated with the presence of eschars in febrile patients compared with the healthy skin from the control group. Finally, we confirmed that Senegal is an endemic region for R. felis, which is found in both eschars and healthy skin swabs.

Identification of rickettsial pathogens in ixodid ticks in northern Senegal

The spotted fevers, caused by the Rickettsia bacteria, are a group of emerging diseases that are responsible for significant human morbidity. In Africa, the distribution of different species of Rickettsia in their tick vectors is poorly studied. We have collected 1169 hard ticks from 5 different species in the northern Senegal, close to the Saharan border. In a far northern collection site, corresponding to the Rickettsia africae distribution area, we collected three Amblyomma variegatum ticks infected by R. africae. Rickettsia africae was also identified in a Hyalomma marginatum rufipes tick, which may represent the secondary host for the pathogen. Rickettsia aeschlimannii was identified in H. m. rufipes, Rhipicephalus evertsi evertsi, and Hyalomma impeltatum ticks.

Case report of African tick-bite fever from Poland

A confirmed case of rickettsiosis acquired in South Africa and recognized in Poland was described. The patient fulfilled clinical criteria highly suggestive of African tick bite fever, such as eschars, regional lymphadenitis, cutaneous rash within 10 days after his return from sub-Saharan Africa. Infection with Rickettsia africae was confirmed by polymerase chain reaction and sequencing.

Common epidemiology of Rickettsia felis infection and malaria, Africa

This study aimed to compare the epidemiology of Rickettsia felis infection and malaria in France, North Africa, and sub-Saharan Africa and to identify a common vector. Blood specimens from 3,122 febrile patients and from 500 nonfebrile persons were analyzed for R. felis and Plasmodium spp. We observed a significant linear trend (p<0.0001) of increasing risk for R. felis infection. The risks were lowest in France, Tunisia, and Algeria (1%), and highest in rural Senegal (15%). Co-infections with R. felis and Plasmodium spp. and occurrences of R. felis relapses or reinfections were identified. This study demonstrates a correlation between malaria and R. felis infection regarding geographic distribution, seasonality, asymptomatic infections, and a potential vector. R. felis infection should be suspected in these geographical areas where malaria is endemic. Doxycycline chemoprophylaxis against malaria in travelers to sub-Saharan Africa also protects against rickettsioses; thus, empirical treatment strategies for febrile illness for travelers and residents in sub-Saharan Africa may require reevaluation.

High prevalence of spotted fever group rickettsiae in Amblyomma variegatum from Uganda and their identification using sizes of intergenic spacers

The spotted fever group (SFG) rickettsiae are obligate intracellular bacteria transmitted by ticks that cause several tick-borne rickettsioses in humans worldwide. This study was intended to determine the prevalence of SFG rickettsiae in Amblyomma variegatum from 7 districts across Uganda. In addition to sequencing of gltA and ompA genes, identification of Rickettsia species based on the sizes of highly variable intergenic spacers, namely, dksA-xerC, mppA-purC, and rpmE-tRNA(fMet) was carried out. Application of multiplex PCR for simultaneous amplification of 3 spacers combined with capillary electrophoresis separation allowed simple, accurate, and high-throughput fragment sizing with considerable time and cost savings. Rickettsia genus-specific real-time PCR detected 136 positives out of 140 samples, giving an overall prevalence of 97.1%. Most samples (n=113) had a size combination of 225, 195, and 341 bp for dksA-xerC, mppA-purC, and rpmE-tRNA(fMet), respectively, which was identical to that of R. africae, a causative agent of African tick bite fever. In addition, several samples had size variants in either dksA-xerC or rpmE-tRNA(fMet). Nonetheless, the partial sequences of gltA and ompA genes of samples of all size combinations showed the greatest similarity to R. africae (99.3-100% for gltA and 98.1-100% for ompA). Given these results, it is highly possible that the tested ticks were infected with R. africae or closely related species. This is a first report on molecular genetic detection of R. africae and its high endemicity in Uganda. Clinicians in this country should be aware of this pathogen as a cause of non-malarial febrile illness. This study provided a starting point for the development of Rickettsia species identification based on the sizes of intergenic spacers. The procedure is simple, rapid, and cost-effective to perform; hence it might be particularly well suited for preliminary species identification in epidemiological investigations. The results may be more detailed and reliable when simultaneous sequencing analysis is performed.

Update on tick-borne rickettsioses around the world: a geographic approach

Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases.

Detection of a new Borrelia species in ticks taken from cattle in Southwest Ethiopia

We collected 284 ticks in Ethiopia (109 Amblyomma cohaerens, 173 Rhipicephalus decoloratus, and 2 Rhipicephalus praetextatus). We found no rickettsiae and bartonellae. In 7.3% of the A. cohaerens, we found a Borrelia sp. that may represent a new species distant from both relapsing fever group and Lyme borreliae.

Point-of-care laboratory of pathogen diagnosis in rural Senegal

BACKGROUND

In tropical Africa, where the spectrum of the bacterial pathogens that cause fevers is poorly understood and molecular-based diagnostic laboratories are rare, the time lag between test results and patient care is a critical point for treatment of disease.

METHODOLOGY/PRINCIPAL FINDINGS

We implemented POC laboratory in rural Senegal to resolve the time lag between test results and patient care. During the first year of the study (February 2011 to January 2012), 440 blood specimens from febrile patients were collected in Dielmo and Ndiop villages. All samples were screened for malaria, dengue fever, Borrelia spp., Coxiella burnetii, Tropheryma whipplei, Rickettsia conorii, R. africae, R. felis, and Bartonella spp.

CONCLUSIONS/SIGNIFICANCE

We identified DNA from at least one pathogenic bacterium in 80/440 (18.2%) of the samples from febrile patients. B. crocidurae was identified in 35 cases (9.5%), and R. felis DNA was found in 30 cases (6.8%). The DNA of Bartonella spp. was identified in 23/440 cases (4.3%), and DNA of C. burnetii was identified in 2 cases (0.5%). T. whipplei (0.2%) was diagnosed in one patient. No DNA of R. africae or R. conorii was identified. Among the 7 patients co-infected by two different bacteria, we found R. felis and B. crocidurae in 4 cases, B. crocidurae and Bartonella spp. in 2 cases, and B. crocidurae and C. burnetii in 1 case. Malaria was diagnosed in 54 cases. In total, at least one pathogen (bacterium or protozoa) was identified in 127/440 (28.9%) of studied samples. Here, the authors report the proof of concept of POC in rural tropical Africa. Discovering that 18.2% of acute infections can be successfully treated with doxycycline should change the treatment strategy for acute fevers in West Africa.

Vectors of rickettsiae in Africa

Vector-borne diseases are caused by parasites, bacteria, or viruses transmitted by the bites of hematophagous arthropods. In Africa, there has been a recent emergence of new diseases and the re-emergence of existing diseases, usually with changes in disease epidemiology (e.g., geographical distribution, prevalence, and pathogenicity). In Africa, rickettsioses are recognized as important emerging vector-borne infections in humans. Rickettsial diseases are transmitted by different types of arthropods, ticks, fleas, lice, and mites. This review will examine the roles of these different arthropod vectors and their geographical distributions.

Treatable bacterial infections are underrecognized causes of fever in Ethiopian children

Febrile illnesses remain a major cause of morbidity and mortality in resource-poor countries, but too often, tests are not available to determine the causes, leading to misdiagnosis and inappropriate treatment. To determine the cause of febrile illnesses, we recovered the malaria smears from 102 children presenting with fever to Soddo Christian Hospital in Wolaitta Soddo, Ethiopia. DNA was isolated from the smears and evaluated by real-time polymerase chain reaction. We identified pathogen DNA with probes for Plasmodium spp., Streptococcus pneumoniae, Rickettsia spp., Salmonella spp., and Borrelia spp. Overall, we showed that it is possible to isolate high-quality DNA and identify treatable pathogens from malaria blood smears. Furthermore, our data showed that bacterial pathogens (especially Pneumococcus, Rickettsia spp., and Borrelia spp.) are common and frequently unrecognized but treatable causes of febrile illnesses in Ethiopian children.

Molecular identification of tick-borne pathogens in Nigerian ticks

A molecular epidemiology investigation was undertaken in two Nigerian states (Plateau and Nassarawa) to determine the prevalence of pathogens of veterinary and public health importance associated with ticks collected from cattle and dogs using PCR, cloning and sequencing or reverse line blot techniques. A total of 218 tick samples, Amblyomma variegatum (N=153), Rhipicephalus (Boophilus) decoloratus (N=45), and Rhipicephalus sanguineus (N=20) were sampled. Pathogens identified in ticks included piroplasmids (Babesia spp., Babesia bigemina and Babesia divergens), Anaplasma marginale and Rickettsia africae. Piroplasmids were identified in A. variegatum, A. marginale was found in R. decoloratus, while R. africae was detected in all tick species examined. Ehrlichia spp. and Theileria spp. were not identified in any of the ticks examined. Of the 218 ticks examined, 33 (15.1%) contained pathogen DNA, with the presence of B. divergens and R. africae that are zoonotic pathogens of public health and veterinary importance. The variety of tick-borne pathogens identified in this study suggests a risk for the emergence of tick-borne diseases in domestic animals and humans, especially amongst the Fulani pastoralists in Plateau and Nassarawa states of Nigeria.

Tick-borne rickettsioses, neglected emerging diseases in rural Senegal

BACKGROUND

Rickettsioses are one of the most important causes of systemic febrile illness among travelers from developed countries, but little is known about their incidence in indigenous populations, especially in West Africa.

METHODOLOGY/PRINCIPAL FINDINGS

Overall seroprevalence evaluated by immunofluorescence using six rickettsial antigens (spotted fever and typhus group) in rural populations of two villages of the Sine-Saloum region of Senegal was found to be 21.4% and 51% for spotted fever group rickettsiae for Dielmo and Ndiop villages, respectively. We investigated the role of tick-borne rickettsiae as the cause of acute non-malarial febrile diseases in the same villages. The incidence of rickettsial DNA in 204 blood samples from 134 (62M and 72F) febrile patients negative for malaria was studied. DNA extracted from whole blood was tested by two qPCR systems. Rickettsial DNA was found in nine patients, eight with Rickettsia felis (separately reported). For the first time in West Africa, Rickettsia conorii was diagnosed in one patient. We also tested 2,767 Ixodid ticks collected in two regions of Senegal (Niakhar and Sine-Saloum) from domestic animals (cows, sheep, goats, donkeys and horses) by qPCR and identified five different pathogenic rickettsiae. We found the following: Rickettsia aeschlimannii in Hyalomma marginatum rufipes (51.3% and 44.8% in Niakhar and Sine-Saloum region, respectively), in Hyalomma truncatum (6% and 6.8%) and in Rhipicephalus evertsi evertsi (0.5%, only in Niakhar); R. c. conorii in Rh. e. evertsi (0.4%, only in Sine-Saloum); Rickettsia massiliae in Rhipicephalus guilhoni (22.4%, only in Niakhar); Rickettsia sibirica mongolitimonae in Hyalomma truncatum (13.5%, only in Sine-Saloum); and Rickettsia africae in Rhipicephalus evertsi evertsi (0.7% and 0.4% in Niakhar and Sine-Saloum region, respectively) as well as in Rhipicephalus annulatus (20%, only in Sine-Saloum). We isolated two rickettsial strains from H. truncatum: R. s. mongolitimonae and R. aeschlimannii.

CONCLUSIONS/SIGNIFICANCE

We believe that together with our previous data on the high prevalence of R. africae in Amblyomma ticks and R. felis infection in patients, the presented results on the distribution of pathogenic rickettsiae in ticks and the first R. conorii case in West Africa show that the rural population of Senegal is at risk for other tick-borne rickettsioses, which are significant causes of febrile disease in this area.