Surveillance of Egyptian fleas for agents of public health significance: Anaplasma, Bartonella, Coxiella, Ehrlichia, Rickettsia, and Yersinia pestis.
01 Jul 2006-American Journal of Tropical Medicine and Hygiene (American Society of Tropical Medicine and Hygiene)-Vol. 75, Iss: 1, pp 41-48
TL;DR: Serologic surveys in Egypt have documented human and animal exposure to vector-borne bacterial pathogens, but the presence and distribution of these agents in arthropods has not been determined and fleas were collected from mammals trapped in 17 cities throughout Egypt.
Abstract: Serologic surveys in Egypt have documented human and animal exposure to vector-borne bacterial pathogens, but the presence and distribution of these agents in arthropods has not been determined. Between July 2002 and July 2003, fleas were collected from 221 mammals trapped in 17 cities throughout Egypt. A total of 987 fleas were collected, representing four species (Ctenocephalides felis, Echidnophaga gallinacea, Leptopsylla segnis, and Xenopsylla cheopis); 899 of these fleas were X. cheopis from rats (Rattus spp.). Fleas were tested for DNA from Anaplasma spp., Bartonella spp., Coxiella burnetii, Ehrlichia spp., Rickettsia spp., and Yersinia pestis. Rickettsia typhi, the agent of murine typhus, was detected in X. cheopis and L. segnis from rats from nine cities. A spotted-fever group Rickettsia sp. similar to "RF2125" was detected in E. gallinacea, and two unidentified spotted fever group Rickettsia were detected in two X. cheopis. Novel Bartonella genotypes were detected in X. cheopis and L. segnis from three cities. Coxiella burnetii was detected in two fleas. Anaplasma, Ehrlichia, and Y. pestis were not detected.
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TL;DR: An overall review of flea biology and the distribution of the flea-borne diseases of public health importance throughout the world, their principal flea vectors, and the extent of their public health burden is reviewed.
318 citations
Cites background from "Surveillance of Egyptian fleas for ..."
...The cat flea is extremely common on cats and dogs in many temperate and tropical regions, but it also infests opossums,(27) raccoons,(27) and rats.(28) It represents the great majority of fleas in human homes....
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TL;DR: A review of Bartonella transmission by sandflies, lice and fleas, the potential for transmission by other vectors, and data supporting transmission by ticks suggests there is substantial opportunity for the potential uptake of these blood‐borne bacteria by a variety of arthropod vectors that feed on animals and people.
Abstract: Bartonella species are gram-negative bacteria that infect erythrocytes, endothelial cells and macrophages, often leading to persistent blood-borne infections. Because of the ability of various Bartonella species to reside within erythrocytes of a diverse number of animal hosts, there is substantial opportunity for the potential uptake of these blood-borne bacteria by a variety of arthropod vectors that feed on animals and people. Five Bartonella species are transmitted by lice, fleas or sandflies. However, Bartonella DNA has been detected or Bartonella spp. have been cultured from numerous other arthropods. This review discusses Bartonella transmission by sandflies, lice and fleas, the potential for transmission by other vectors, and data supporting transmission by ticks. Polymerase chain reaction (PCR) or culture methods have been used to detect Bartonella in ticks, either questing or host-attached, throughout the world. Case studies and serological or molecular surveys involving humans, cats and canines provide indirect evidence supporting transmission of Bartonella species by ticks. Of potential clinical relevance, many studies have proposed co-transmission of Bartonella with other known tick-borne pathogens. Currently, critically important experimental transmission studies have not been performed for Bartonella transmission by many potential arthropod vectors, including ticks.
279 citations
TL;DR: To assess the presence of rickettsial pathogens in ticks from Egypt, ticks from domestic and peridomestic animals were collected between June 2002 and July 2003 and DNA extracts from 1019 ticks were tested for Anaplasma marginale, Coxiella burnetii, Rickettsia aeschlimannii, and four novel genotypes similar to “Anaplasma platys.”
Abstract: To assess the presence of rickettsial pathogens in ticks from Egypt, we collected ticks from domestic and peridomestic animals between June 2002 and July 2003. DNA extracts from 1019 ticks were tested, using PCR and sequencing, for Anaplasma spp., Bartonella spp., Coxiella burnetii, Ehrlichia spp., and Rickettsia spp. Ticks included: 29 Argas persicus, 10 Hyalomma anatolicum anatolicum, 55 Hyalomma anatolicum excavatum, 174 Hyalomma dromedarii, 2 Hyalomma impeltatum, 3 Hyalomma marginatum rufipes, 55 unidentified nymphal Hyalomma, 625 Rhipicephalus (Boophilus) annulatus, 49 Rhipicephalus sanguineus, and 17 Rhipicephalus turanicus. Ticks were collected predominantly (>80%) from buffalo, cattle, and camels, with smaller numbers from chicken and rabbit sheds, sheep, foxes, a domestic dog, a hedgehog, and a black rat. We detected Anaplasma marginale, Coxiella burnetii, Rickettsia aeschlimannii, and four novel genotypes similar to: “Anaplasma platys,” Ehrlichia canis, Ehrlichia spp. reported from Asian ticks, and a Rickettsiales endosymbiont of Ixodes ricinus.
145 citations
Cites background or methods from "Surveillance of Egyptian fleas for ..."
...DNA from Coxiella burnetii has also been detected in fleas and lice from Egypt (Loftis et al. 2006; Reeves et al. 2006)....
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...Sequencing and GenBank accession numbers PCR amplicons were sequenced as previously described (Loftis et al. 2006)....
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...The assays have sensitivities of ~10 gene copies per microliter of DNA extract (Jiang et al. 2004; Li et al. 2001; Loftis et al. 2006); the assay for the multicopy IS1111 element of Coxiella burnetii has a sensitivity of approximately one organism per microliter....
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..., such as those detected in Egyptian fleas (Loftis et al. 2006)....
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...The serologic reactivity to spotted-fever group Rickettsia previously reported in animals and people from Egypt could also result from unrecognized infections with R. aeschlimanii or other Rickettsia spp., such as those detected in Egyptian fleas (Loftis et al. 2006)....
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TL;DR: 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.
Abstract: 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.
126 citations
TL;DR: The epidemiological and pathological features of Rickettsia are summarized and the genomic findings that help the understanding of the evolution of pathogenicity including the deleterious mutations of repair systems and the toxin-antitoxin systems are discussed.
125 citations
References
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TL;DR: The sensitivity of the commonly used progressive multiple sequence alignment method has been greatly improved and modifications are incorporated into a new program, CLUSTAL W, which is freely available.
Abstract: The sensitivity of the commonly used progressive multiple sequence alignment method has been greatly improved for the alignment of divergent protein sequences. Firstly, individual weights are assigned to each sequence in a partial alignment in order to down-weight near-duplicate sequences and up-weight the most divergent ones. Secondly, amino acid substitution matrices are varied at different alignment stages according to the divergence of the sequences to be aligned. Thirdly, residue-specific gap penalties and locally reduced gap penalties in hydrophilic regions encourage new gaps in potential loop regions rather than regular secondary structure. Fourthly, positions in early alignments where gaps have been opened receive locally reduced gap penalties to encourage the opening up of new gaps at these positions. These modifications are incorporated into a new program, CLUSTAL W which is freely available.
63,427 citations
"Surveillance of Egyptian fleas for ..." refers methods in this paper
...Sequences were aligned using ClustalW.46 Unrooted parsimony analysis (1,002 bp) of the aligned sequences was performed using the Phylip 3.62 software package,47 and 100 bootstrap replicates were performed....
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...Sequences were aligned using ClustalW.(46) Unrooted parsimony analysis (1,002 bp) of the aligned sequences was performed using the Phylip 3....
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Journal Article•
16,851 citations
TL;DR: Comparison of gltA sequences could be a complementary approach to 16S rDNA sequencing for inferring bacterial evolution, especially when unstable phylogenetic models are obtained from ribosomal sequences because of high levels of sequence similarity between the bacteria studied.
Abstract: Using PCR and an automated laser fluorescent DNA sequencer, we amplified and sequenced a 1,234-bp fragment of the citrate synthase-encoding gene (gltA) of 28 bacteria belonging to the genus Rickettsia. Comparative sequence analysis showed that most of the spotted fever group (SFG) rickettsiae belonged to one of two subgroups. The first subgroup included Rickettsia massiliae, strain Bar 29, Rickettsia rhipicephali, “Rickettsia aeschlimanni,” and Rickettsia montana, which have been isolated only from ticks. The second subgroup was larger and included the majority of the human pathogens and also rickettsiae isolated only from ticks; the members of this subgroup were strain S, Rickettsia africae, “Rickettsia mongolotimonae,” Rickettsia sibirica, Rickettsia parkeri, Rickettsia conorii, Rickettsia rickettsii, the Thai tick typhus rickettsia, the Israeli tick typhus rickettsia, the Astrakhan fever rickettsia, “Rickettsia slovaca,” and Rickettsia japonica. The sequence analysis also showed that the tick-borne organisms Rickettsia helvetica and Rickettsia australis and the mite-borne organism Rickettsia akari were associated with the SFG cluster; that Rickettsia prowazekii and Rickettsia typhi, two representatives of the typhus group, clustered together; and that Rickettsia canada, Rickettsia bellii, and the AB bacterium probably represent three new groups. We compared the phylogenetic trees inferred from citrate synthase gene sequences and from 16S ribosomal DNA (rDNA) sequences. For rickettsial phylogeny, the citrate synthase approach was more suitable, as demonstrated by significant bootstrap values for all of the nodes except those in the larger subgroup defined above. We also compared phylogenetic analysis results obtained in a comparison of the sequences of both genes for all of the representatives of the domain Bacteria for which the gltA sequence was determined. We believe that comparison of gltA sequences could be a complementary approach to 16S rDNA sequencing for inferring bacterial evolution, especially when unstable phylogenetic models are obtained from ribosomal sequences because of high levels of sequence similarity between the bacteria studied.
509 citations
"Surveillance of Egyptian fleas for ..." refers methods in this paper
...In addition, the citrate synthase gene of Rickettsia was amplified from E. gallinacea, using primers RCPS877F and RCPS1258R.42 A PCR assay that amplifies the pla gene of Y. pestis was used as described by Stevenson and others43 with the following modification: if a sample tested negative after 40 cycles of amplification, the assay was nested, using the same primers, for an additional 30 cycles of amplification....
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...using primers RCPS877F and RCPS1258R.(42) A PCR assay that amplifies the pla gene of Y....
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TL;DR: The current understanding of the microbiology, pathogenesis, and clinical manifestations associated with this pathogen are summarized but focus primarily on discussing various ecological factors responsible for the recent recognition of this important and potentially life-threatening tick-borne disease.
Abstract: Ehrlichia chaffeensis is an obligately intracellular, tick-transmitted bacterium that is maintained in nature in a cycle involving at least one and perhaps several vertebrate reservoir hosts. The moderate to severe disease caused by E. chaffeensis in humans, first identified in 1986 and reported for more than 1,000 patients through 2000, represents a prototypical “emerging infection.” Knowledge of the biology and natural history of E. chaffeensis, and of the epidemiology, clinical features, and laboratory diagnosis of the zoonotic disease it causes (commonly referred to as human monocytic ehrlichiosis [HME]) has expanded considerably in the period since its discovery. In this review, we summarize briefly the current understanding of the microbiology, pathogenesis, and clinical manifestations associated with this pathogen but focus primarily on discussing various ecological factors responsible for the recent recognition of this important and potentially life-threatening tick-borne disease. Perhaps the most pivotal element in the emergence of HME has been the staggering increases in white-tailed deer populations in the eastern United States during the 20th century. This animal serves as a keystone host for all life stages of the principal tick vector (Amblyomma americanum) and is perhaps the most important vertebrate reservoir host for E. chaffeensis. The contributions of other components, including expansion of susceptible human populations, growth and broadening geographical distributions of other potential reservoir species and A. americanum, and improvements in confirmatory diagnostic methods, are also explored.
451 citations
TL;DR: Patients suspected of having human granulocytic ehrlichiosis (HGE) should be treated with a tetracycline-class antibiotic while awaiting the outcome of confirmatory laboratory testing.
Abstract: Human granulocytic ehrlichiosis is a recently recognized tick-borne infectious disease, and to date >600 patients have been identified in the United States and Europe. Most patients have presented with a non-specific febrile illness occurring within 4 weeks after tick exposure or tick bite. The risk for serious illness or death increases with advancing age and delayed onset of therapy. Routine laboratory testing may reveal reduced white blood cell and platelet concentrations and mildly elevated hepatic transaminase activity in peripheral blood. A high index of suspicion is necessary to arrive at a timely clinical diagnosis. Patients suspected of having human granulocytic ehrlichiosis (HGE) should be treated with a tetracycline-class antibiotic while awaiting the outcome of confirmatory laboratory testing.
264 citations