Molecular detection of Rickettsia felis and Bartonella henselae in dog and cat fleas in Central Oromia, Ethiopia

Detection of Bacterial Infections and Malaria among Blood Culture-Negative Samples of Hospitalized Febrile Patients from a Tertiary Hospital in Ethiopia

Febrile illnesses contribute significantly to morbidity and mortality in sub-Saharan Africa, but the lack of diagnostic facilities and the broad spectrum of pathogens can lead to inadequate clinical management. The timely and reliable identification of the causative pathogens in febrile patients is the basis for the administration of optimal treatment. We aimed to evaluate the performance of a multiplex polymerase chain reaction (PCR) among blood culture-negative patients presenting with febrile diseases in Central Ethiopia. From April 2016 to June 2018, we collected blood samples from adults and children ≥1 year of age admitted with febrile diseases to the Asella Referral and Teaching Hospital, which is located at an altitude of 2,400 m. Total nucleic acids were extracted from frozen plasma samples using a MagNA Pure 96 instrument (Roche, Mannheim, Germany). The multiplex PCR assays were used in combination with LightCycler multiplex DNA master mix (Roche) on a LightCycler 480 instrument (Roche). We used the pathogen-specific assays targeted to Plasmodium spp., Borrelia spp., Rickettsia spp., Leptospira spp., Salmonella spp., and arboviruses. We tested plasma samples of 511 patients and found positive results for Plasmodium spp. (13, 2.5%), Borrelia spp. (12, 2.3%), and Rickettsia species (7, 1.3%); in total, pathogens were detected in 32 of the samples (6.3%). No pathogen was detected by multiplex PCR in 94% of blood culture-negative samples. Even if the pathogens identified by PCR were not necessarily causes of fever, molecular testing using a multiplex PCR can contribute to pathogen diagnosis in a proportion of febrile patients in the highland part of Ethiopia and help to improve the clinical management.

Epidemiological Survey on Tick-Borne Pathogens with Zoonotic Potential in Dog Populations of Southern Ethiopia

Dogs are known to host several tick-borne pathogens with zoonotic potential; however, scant information is available on the epidemiology of these pathogens in low-income tropical countries and in particular in sub-Saharan Africa. With the aim of investigating a wide range of tick-borne pathogens (i.e., Rickettsia spp., Anaplasma spp., Erhlichia spp., Borrelia spp., Hepatozoon spp. and Babesia spp.), 273 blood samples were collected from dogs in selected districts of Ethiopia and analyzed by real-time and/or end-point PCR. The results of the study showed that Hepatozoon canis was the most prevalent pathogen (53.8%), followed by Anaplasma phagocythophilum (7.0%), Babesia canis rossi (3.3%), Ehrlichia canis (2.6%) and Anaplasma platys (2.2%). Furthermore, five samples tested positive for Borrelia spp., identified as Borrelia afzelii (n = 3) and Borrelia burgdorferi (n = 2), and two samples for Rickettsia spp., identified as Rickettsia conorii (n = 1) and Rickettsia monacensis (n = 1). The finding of Anaplasma phagocythophilum and different species of the genera Borrelia and Rickettsia with zoonotic potential was unexpected and alarming, and calls for further investigation on the roles of dogs and on the tick, species acting as vector in this specific context. Other pathogens (Hepatozoon canis, Babaesia canis rossi, Anaplasma platys, Ehrlichia canis) are already known to have an important impact on the dogs' health but have minor zoonotic potential as they were rarely or never reported in humans. Dogs from rural areas were found to be at higher risk for different pathogens, probably due to the presence of other wild canids in the same environment. The findings of the present study contribute to a better knowledge of the epidemiology of tick-borne pathogens, which is relevant to human and animal health.

Didelphis spp. opossums and their parasites in the Americas: A One Health perspective

Medium sized opossums (Didelphis spp.) are among the most fascinating mammals of the Americas, playing important ecological roles (e.g., dispersal of seeds and control of insect populations) in the environment they inhabit. Nevertheless, as synanthropic animals, they are well adapted to human dwellings, occupying shelters within the cities, peripheral areas, and rural settings. These marsupials can harbor numerous pathogens, which may affect people, pets, and livestock. Among those, some protozoa (e.g., Leishmania infantum, Trypanosoma cruzi, Toxoplasma gondii), helminths (e.g., Ancylostoma caninum, Trichinella spiralis, Alaria marcianae, Paragonimus spp.) and arthropods (e.g., ticks, fleas) present substantial public health and veterinary importance, due to their capacity to cause disease in humans, domestic animals, and wildlife. Here, we reviewed the role played by opossums on the spreading of zoonotic parasites, vectors, and vector-borne pathogens, highlighting the risks of pathogens transmission due to the direct and indirect interaction of humans and domestic animals with Didelphis spp. in the Americas.

Flea-borne pathogens in the cat flea Ctenocephalides felis and their association with mtDNA diversity of the flea host

Flea-borne pathogens were screened from 100 individual cat fleas using a PCR approach, of which 38 % were infected with at least one bacterium. Overall, 28 % of the flea samples were positive for Bartonella as inferred from ITS DNA region. Of these, 25 % (7/28) were identified as Bartonella clarridgeiae, 42.9 % (12/28) as Bartonella henselae consisted of two different strains, and 32.1 % (9/28) as Bartonella koehlerae, which was detected for the first time in Malaysia. Sequencing of gltA amplicons detected Rickettsia DNA in 14 % of cat flea samples, all of them identified as Rickettsia asembonensis (100 %). None of the flea samples were positive for Mycoplasma DNA in 16S rRNA gene detection. Four fleas were co-infected with Bartonella and Rickettsia DNAs. Statistical analyses reveal no significant association between bacterial infection and mtDNA diversity of the cat flea. Nevertheless, in all types of pathogen infections, infected populations demonstrated lower nucleotide and haplotype diversities compared to uninfected populations. Moreover, lower haplotype numbers were observed in infected populations.

Fleas and flea-borne diseases of North Africa

North Africa has an interesting and rich wildlife including hematophagous arthropods, and specifically fleas, which constitute a large part of the North African fauna, and are recognised vectors of several zoonotic bacteria. Flea-borne organisms are widely distributed throughout the world in endemic disease foci, where components of the enzootic cycle are present. Furthermore, flea-borne diseases could re-emerge in epidemic form because of changes in the vector-host ecology due to environmental and human behaviour modifications. We need to know the real incidences of flea-borne diseases in the world due to this incidence could be much greater than are generally recognized by physicians and health authorities. As a result, diagnosis and treatment are often delayed by health care professionals who are unaware of the presence of these infections and thus do not take them into consideration when attempting to determine the cause of a patient's illness. In this context, this bibliographic review aims to summarise the main species of fleas present in North Africa, their geographical distribution, flea-borne diseases, and their possible re-emergence.

Infection rate and molecular characterization of Echidnophaga gallinacea in chickens from Matrouh Governorate, Egypt

Echidnophaga gallinacea is the sticktight flea of chickens. It causes dermatitis and ulcers in the skin and carries some disease-causing agents such as Rickettsia and Bartonella. This study was conducted to detect the infection rate and elucidate the molecular characterization of E. gallinacea in chickens from El-Dabaa City, Matrouh Governorate, Egypt. The fleas were collected from infected chickens and identified morphologically. The internal transcribed spacer-1 (ITS-1) gene PCR method was used for molecular characterization. Based on the morphology, the collected fleas were confirmed as E. gallinacea. The overall infection rate was 5%, with 4.5% in female and 10% in male chickens. ITS-1 PCR revealed a specific band of 488 bp. The ITS-1 gene sequence from Egypt occurred in the same phylogenetic clade as that from Cameroon, with a percentage identity of 98.47%.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as a useful tool for the rapid identification of wild flea vectors preserved in alcohol

Flea identification is a significant issue because some species are considered as important vectors of several human pathogens that have emerged or re-emerged recently, such as Bartonella henselae (Rhizobiales: Bartonellaceae) and Rickettsia felis (Rickettsiales: Rickettsiaceae). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been evaluated in recent years for the identification of multicellular organisms, including arthropods. A preliminary study corroborated the usefulness of this technique for the rapid identification of fleas, creating a preliminary database containing the spectra of five species of flea. However, longterm flea preservation in ethanol did not appear to be an adequate method of storage in the context of specimen identification by MALDI-TOF MS profiling. The goal of the present work was to assess the performance of MALDI-TOF MS in the identification of seven flea species [Ctenocephalides felis (Siphonaptera: Pulicidae), Ctenocephalides canis, Pulex irritans (Siphonaptera: Pulicidae), Archaeopsylla erinacei (Siphonaptera: Pulicidae), Leptopsylla taschenbergi (Siphonaptera: Ceratophyllidae), Stenoponia tripectinata (Siphonaptera: Stenoponiidae) and Nosopsyllus fasciatus (Siphonaptera: Ceratophyllidae)] collected in the field and stored in ethanol for different periods of time. The results confirmed that MALDI-TOF MS can be used for the identification of wild fleas stored in ethanol. Furthermore, this technique was able to discriminate not only different flea genera, but also the two congeneric species C. felis and C. canis.

Fleas from domestic dogs and rodents in Rwanda carry Rickettsia asembonensis and Bartonella tribocorum

Fleas (Siphonaptera) are ubiquitous blood-sucking parasites that transmit a range of vector-borne pathogens. The present study examined rodents (n = 29) and domestic dogs (n = 7) living in the vicinity of the Volcanoes National Park, Rwanda, for fleas, identified flea species from these hosts, and detected Bartonella (Rhizobiales: Bartonellaceae) and Rickettsia (Rickettsiales: Rickettsiaceae) DNA. The most frequently encountered flea on rodents was Xenopsylla brasiliensis (Siphonaptera: Pulicidae). In addition, Ctenophthalmus (Ethioctenophthalmus) calceatus cabirus (Siphonaptera: Hystrichopsyllidae) and Ctenocephalides felis strongylus (Siphonaptera: Pulicidae) were determined using morphology and sequencing of the cytochrome c oxidase subunit I and cytochrome c oxidase subunit II genes (cox1 and cox2, respectively). Bartonella tribocorum DNA was detected in X. brasiliensis and Rickettsia asembonensis DNA (a Rickettsia felis-like organism) was detected in C. felis strongylus. The present work complements studies that clarify the distributions of flea-borne pathogens and potential role of fleas in disease transmission in sub-Saharan Africa. In the context of high-density housing in central sub-Saharan Africa, the detection of B. tribocorum and R. asembonensis highlights the need for surveillance in both rural and urban areas to identify likely reservoirs.

Ectoparasites infesting dogs and cats in Bishoftu, central Oromia, Ethiopia

A total of 200 dogs and 137 cats were examined for the presence of fleas, ticks and lice in Bishoftu, central Oromia, Ethiopia from September 2009 through April 2010. At least one ectoparasite species was found on 97% (194/200) of the dogs and 90.5% (124/137) of the cats. On dogs, fleas (Ctenocephalides felis (95%), Pulex irritans (20.5%), Echidnophaga gallinacea (9%) and Xenopsylla cheopis (0.5%)), ticks (Haemaphysalis leachi (17.5%), Amblyomma variegatum (8.5%), Rhipicephalus sanguineus (8%), Rhipicephalus pulchellus (5.5%) and Rhipicephalus (Boophilus) decoloratus (2.5%)) and lice (Heterodoxus spiniger (5%), Linognathus setosus (1.5%) and Trichodectes canis (0.5%)) were identified. On cats, fleas (C. felis (61.7%), E. gallinacea (24.1%), P. irritans (1.5%) and X. cheopis (0.7%)) and ticks (Ha. leachi (10.9%), Am. variegatum (1.5%) and Rh. sanguineus (0.7%)) were identified. C. felis was identified as the predominant ectoparasite on both dogs and cats. The overall frequency and count of ectoparasites was higher on dogs than on cats. Significantly higher overall frequency of fleas on young versus adult cats (p = .01) was recorded. However, ticks were significantly higher on adult cats than on young cats (p = .01). In conclusion, this study demonstrated great species diversity and high frequency of ectoparasites on dogs and cats in the study area. Further studies are required to investigate the role of these ectoparasites in transmission of zoonotic pathogens to humans and animals in Ethiopia.

Comparison of Zoonotic Bacterial Agents in Fleas Collected from Small Mammals or Host-Seeking Fleas from a Ugandan Region Where Plague Is Endemic

Fleas play critical roles in transmitting some infections among animals and from animals to humans. Detection of pathogens in fleas is important to determine human risks for flea-borne diseases and can help guide diagnosis and treatment. Our findings of high prevalence rates of B. elizabethae and R. felis in fleas in the Arua and Zombo districts of Uganda implicate these agents as potential causative agents of undiagnosed febrile illnesses in this area.

Fleas (n = 407) were collected from small mammals trapped inside huts and surroundings of homesteads in five villages within the Arua and Zombo districts of Uganda. The most common flea species were Dinopsyllus lypusus (26%) and Xenopsylla cheopis (50%). Off-host fleas (n = 225) were collected inside huts by using Kilonzo flea traps. The majority of the off-host fleas were Ctenocephalides felis (80%). All fleas were examined for the presence of Bartonella spp., Rickettsia spp., and Yersinia spp. Bartonella DNA was detected in 91 fleas, with an overall prevalence of 14%. Bartonella prevalence was significantly higher in rodent or shrew fleas than in off-host fleas (22% versus 1%). The majority of Bartonella-positive fleas were of the species D. lypusus (61%), X. cheopis (20%), and Ctenophthalmus calceatus (14%). Sequencing analysis identified 12 Bartonella genetic variants, 9 of which belonged to the zoonotic pathogen B. elizabethae species complex. Rickettsia DNA was detected in 143 fleas, giving an overall prevalence of 23%, with a significantly higher prevalence in off-host fleas than in rodent or shrew fleas (56% versus 4%). The majority (88%) of Rickettsia-positive fleas were C. felis and were collected from Kilonzo traps, while a small portion (10%) were X. cheopis collected from rodents. Sequencing analysis identified six Rickettsia genogroups that belonged either to zoonotic R. felis or to the closely related “Candidatus Ricksettia asemboensis” and “Candidatus Ricksettia sengalensis.” Yersinia DNA was not detected in the fleas tested. These observations suggested that fleas in northwestern Uganda commonly carry the zoonotic agents B. elizabethae and R. felis and potentially play an important role in transmitting these infections to humans.

IMPORTANCE Fleas play critical roles in transmitting some infections among animals and from animals to humans. Detection of pathogens in fleas is important to determine human risks for flea-borne diseases and can help guide diagnosis and treatment. Our findings of high prevalence rates of B. elizabethae and R. felis in fleas in the Arua and Zombo districts of Uganda implicate these agents as potential causative agents of undiagnosed febrile illnesses in this area.

High Prevalence of Rickettsia spp. in Dog Fleas (Siphonaptera: Pulicidae) in Rural Uganda

Fleas are known vectors of zoonotic agents. Thirty-five fleas, including 28 Ctenocephalides felis (Bouché), four Pulex irritans (L.), and three Echidnophaga gallinacea (Westwood) from 19 rural dogs from southwestern Uganda were analyzed for the presence of Rickettsia spp. (ompB, gltA, and 17 kDa fragment genes) and Bartonella spp. (rpoB and ITS genes) by PCR. Rickettsial DNA was detected in 27 out of 28 of Ct. felis and in two out of four P. irritans. None of the E. gallinacea specimens harbored Rickettsia DNA. Rickettsia felis was confirmed in 12 Ct. felis and in the two P. irritans specimens with positive PCR-results. In addition, the presence of Candidatus Rickettsia asemboensis was evidenced in 15 Ct. felis. Bartonella spp. was not amplified in any sample. Our survey indicates that R. felis, the agent of the flea-borne spotted fever, is present in the study area. Besides, this is the first description of Ca. R. asemboensis in Uganda.

Bacterial arthropod-borne diseases in West Africa

Arthropods such as ticks, lice, fleas and mites are excellent vectors for many pathogenic agents including bacteria, protozoa and viruses to animals. Moreover, many of these pathogens can also be accidentally transmitted to humans throughout the world. Bacterial vector-borne diseases seem to be numerous and very important in human pathology, however, they are often ignored and are not well known. Yet they are in a phase of geographic expansion and play an important role in the etiology of febrile episodes in regions of Africa. Since the introduction of molecular techniques, the presence of these pathogens has been confirmed in various samples from arthropods and animals, and more rarely from human samples in West Africa. In this review, the aim is to summarize the latest information about vector-borne bacteria, focusing on West Africa from 2000 until today in order to better understand the epidemiological risks associated with these arthropods. This will allow health and veterinary authorities to develop a strategy for surveillance of arthropods and bacterial disease in order to protect people and animals.

Emerging infectious diseases with cutaneous manifestations: Viral and bacterial infections

Given increased international travel, immigration, and climate change, bacterial and viral infections that were once unrecognized or uncommon are being seen more frequently in the Western Hemisphere. A delay in diagnosis and treatment of these diseases can lead to significant patient morbidity and mortality. However, the diagnosis and management of these infections is fraught with a lack of consistency because there is a dearth of dermatology literature on the cutaneous manifestations of these infections. We review the epidemiology, cutaneous manifestations, diagnosis, and management of these emerging bacterial and viral diseases.

Limited Evidence for Rickettsia felis as a Cause of Zoonotic Flea-Borne Rickettsiosis in Southern California

Over 90% of human flea-borne rickettsioses cases in California are reported from suburban communities of Los Angeles and Orange counties and are presumed to be associated with either Rickettsia typhi or Rickettsia felis infection. Ctenocephalides felis (Bouché) is considered the principal vector for both rickettsiae, and R. felis has largely replaced R. typhi as the presumptive etiologic agent based on the widespread incidence of R. felis in cat flea populations. However, with no evidence to confirm R. felis as the cause of human illness in southern California, coupled with recent findings that showed R. felis to be widespread in cat fleas statewide, we propose that this hypothesis should be reconsidered. Evidence of only limited numbers of R. typhi-infected cat fleas in the environment may indicate a very rare infection and explain why so few cases of flea-borne rickettsioses are reported each year in southern California relative to the population.

Morphological, molecular and MALDI-TOF mass spectrometry identification of ixodid tick species collected in Oromia, Ethiopia

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) technology has recently been reported as a promising method for arthropods identification. More recently, our laboratory reported the correct identification of tick species via the MALDI-TOF MS protein spectra profiling of legs from fresh specimens. The aim of the present study was to assess the use of MALDI-TOF MS for correct identification of ixodid tick species preserved in 70 % ethanol during field collection in Ethiopia. Following morphological identification of 12 tick species, the legs from 85 tick specimens were subjected to MALDI-TOF MS. Spectral analysis revealed an intra-species reproducibility and inter-species specificity that were consistent with the morphological classification. To support the results of the MALDI-TOF MS tick species identification, 41 tick specimens comprising 3 to 5 specimens per tick species were used to create a reference spectra database, which was evaluated using the spectra of the 44 remaining tick specimens. The blind tests revealed that 100 % of the tick specimens studied by MALDI-TOF MS were correctly identified. A relevant Log score value (LSV) of >1.8 was recorded for all of the tick species studied by MALDI-TOF MS, except for Rhipicephalus praetextatus. The morphological and MALDI-TOF MS identifications were confirmed by sequencing the 12S ribosomal RNA (rRNA) gene of 40 tick specimens belonging to 11 ixodid species. Taken together, the results of the present study indicate that MALDI-TOF MS is a reliable tool for tick species identification, even after preservation in ethanol, provided that a reference spectra database is built from specimens that represent the respective species stored under the same conditions.

Possible Role of Rickettsia felis in Acute Febrile Illness among Children in Gabon

Infection is widespread but most prevalent among young, rural residents with fever.

Rickettsia felis has been reported to be a cause of fever in sub-Saharan Africa, but this association has been poorly evaluated in Gabon. We assessed the prevalence of this bacterium among children <15 years of age in 4 areas of Gabon; the locations were in urban, semiurban, and rural areas. DNA samples from 410 febrile children and 60 afebrile children were analyzed by quantitative PCR. Overall, the prevalence of R. felis among febrile and afebrile children was 10.2% (42/410 children) and 3.3% (2/60 children), respectively. Prevalence differed among febrile children living in areas that are urban (Franceville, 1.3% [1/77]), semiurban (Koulamoutou, 2.1% [3/141]), and rural (Lastourville, 11.2% [15/134]; Fougamou, 39.7% [23/58]). Furthermore, in a rural area (Fougamou), R. felis was significantly more prevalent in febrile (39.7% [23/58]) than afebrile children (5.0% [1/20]). Additional studies are needed to better understand the pathogenic role of R. felis in this part of the world.

Rickettsia felis, an Emerging Flea-Borne Rickettsiosis

Rickettsia felis is an emerging insect-borne rickettsial pathogen and the causative agent of flea-borne spotted fever. First described as a human pathogen from the USA in 1991, R. felis is now identified throughout the world and considered a common cause of fever in Africa. The cosmopolitan distribution of this pathogen is credited to the equally widespread occurrence of cat fleas (Ctenocephalides felis), the primary vector and reservoir of R. felis. Although R. felis is a relatively new member of the pathogenic Rickettsia, limited knowledge of basic R. felis biology continues to hinder research progression of this unique bacterium. This is a comprehensive review examining what is known and unknown relative to R. felis transmission biology, epidemiology of the disease, and genetics, with an insight into areas of needed investigation.

Wild Red Foxes (Vulpes vulpes) as Sentinels of Parasitic Diseases in the Province of Soria, Northern Spain

Four hundred red foxes (Vulpes vulpes) were examined for ecto- (arthropods) and endoparasites (Leishmania spp., Trichinella spp., and intestinal parasites). Different species of flea (total prevalence, 40.50%), tick (16.25%), mite (7.25%), and fly (1.50%) were identified. The most prevalent flea was Pulex irritans (found on 29% of the foxes); the most prevalent tick, mite, and fly were Ixodes canisuga (on 5%), Sarcoptes scabiei (on 5.25%), and Hippobosca equina (on 1%), respectively. The endoparasites identified included Leishmania spp. (found in 12% of the foxes), Trichinella spp. (in 15.5%, with T. britovi the most prevalent species in 15.25%), Cestoda (in 72.75%, with Mesocestoides spp. the most prevalent in 69.50%), and intestinal ascarids (in 73.25%, with Ancylostoma caninum the most prevalent in 12.50%). No animal was free of parasites. The present results suggest that foxes can act as sentinels of diseases transmitted by ecto- and endoparasites.

Enzootic plague foci, Algeria

In Algeria, PCR sequencing of pla, glpD and rpoB genes found Yersinia pestis in 18/237 (8%) rodents of five species, including Apodemus sylvaticus, previously undescribed as pestiferous; and disclosed three new plague foci. Multiple spacer typing confirmed a new Orientalis variant. Rodent survey should be reinforced in this country hosting reemerging plague.

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.