<i>Ehrlichia chaffeensis:</i>
            a Prototypical Emerging Pathogen

Paddock, CD; Childs, J E

doi:10.1128/cmr.16.2.355.2003

Cited by 120 publications

(259 citation statements)

References 205 publications

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“…The rate found here sounds high but was similar to the rate found among 726 febrile patients without acute rickettsial infection from the city of Juiz de Fora (Costa 2004), and also to others reported elsewhere (Paddock & Childs 2003). In one of the few serologic surveys in South America, Ripoll et al (1999) found 14% of positivity in Argentina but rates have ranged from 2 to 20% throughout the world (Paddock & Childs 2003). Ehrlichia species particularly E. canis have been recently isolated from Brazilian dogs (Machado 2004) indicating the presence of bacteria belonging to this genus in Brazil.…”

Section: Discussionsupporting

confidence: 57%

“…even when using higher cutoffs or without-multiple/cross reactivity seropositivity, expressive numbers of people were positive for E. chaffeensis. The rate found here sounds high but was similar to the rate found among 726 febrile patients without acute rickettsial infection from the city of Juiz de Fora (Costa 2004), and also to others reported elsewhere (Paddock & Childs 2003). In one of the few serologic surveys in South America, Ripoll et al (1999) found 14% of positivity in Argentina but rates have ranged from 2 to 20% throughout the world (Paddock & Childs 2003).…”

Section: Discussionmentioning

confidence: 66%

“…Rickettsial agents are important emerging and reemerging infectious diseases worldwide (Raoult & Roux 1997, Parola & Raoult 2001, Paddock & Childs 2003 and scant information on such conditions can be found either in Brazil or South America (WHO 1993, Rozental et al 2002, Walker 2004a. Until recently the rickettsiales order comprised the genus Rickettsia, Coxiella, Bartonella, Orientia, Anaplasma, and Ehrlichia (Raoult & Roux 1997) and despite of the resulting withdraw of some of them from this order especially due to 16S rRNA studies, they all can be functionally considered rickettsial agents (Raoult & Roux 1997, Walker 2004b.…”

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confidence: 99%

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Antibodies to Rickettsia rickettsii, Rickettsia typhi, Coxiella burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis among healthy population in Minas Gerais, Brazil

Costa

Brigatte

Greco

2005

Mem. Inst. Oswaldo Cruz

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Rickettsial diseases except those belonging to spotted fever group rickettsioses are poorly studied in South America particularly in Brazil where few epidemiological reports have been published. We describe a serosurvey for Rickettsia rickettsii, R. typhi, Coxiella burnetii, Bartonella henselae, B. quintana, and Ehrlichia chaffeensis in 437 healthy people from a Brazilian rural community. The serum samples were tested by indirected micro-immunoflourescence technique and a cutoff titer of 1:64 was used. The seroprevalence rates for R. rickettsii, R. typhi, C. burnetii, B. henselae, B. quintana, and E. chaffeensis were respectively 1.6% (7 samples (WHO 1993, Rozental et al. 2002, Walker 2004a. Until recently the rickettsiales order comprised the genus Rickettsia, Coxiella, Bartonella, Orientia, Anaplasma, and Ehrlichia (Raoult & Roux 1997) and despite of the resulting withdraw of some of them from this order especially due to 16S rRNA studies, they all can be functionally considered rickettsial agents (Raoult & Roux 1997, Walker 2004b.Most of the available publications of Brazilian rickettsial infections have focused on spotted fever group rickettsioses especially R. rickettsii infections (Lemos et al. 1994, Del Guercio et al. 1997, Rozental et al. 2002, Galvão et al. 2003. This issue has been extensively reviewed recently by Galvão (2004). Despite of the fact that new rickettsial agents have been described more recently in Brazil (Oliveira et al. 2002), the whole scenario of rickettsial infections still have black holes reinforcing the nonexistence concept for such infections in this part of the world.The Piau county as well as the southern part of the state of Minas Gerais had been considered free of any rickettsial diseases until 1994 when a family cluster of Brazilian spotted fever was reported (Hallack et al. 1996). Thereafter reports of Brazilian spotted fever have been Given these above mentioned facts and the much-appropriated local ecologic conditions for rickettsial infections we choose this particular region for studying the seroprevalence rates for R. typhi, C. burnetii, B. henselae, B. quintana, and E. chaffeensis as well as R. rickettsii infections among healthy individuals from a Brazilian rural community. MATERIALS AND METHODSSerum samples from 437 healthy individuals of both sexes aged from 5 to 92 years old, living in the county of Piau, state of Minas Gerais, Brazil were tested for the presence of R. rickettsii, R. typhi, C. burnetii phase I and phase II, B. henselae, B. quintana, and E. chaffeensis IgG and IgM antibodies. This county (Fig. 1), located at latitude 21º30'34''S and longitude 43º19'25''W, has 3008 inhabitants, 58% of them living in the small village and the remainders scattered throughout the county, mostly in small farms. The local economics is somehow linked to cattle farming and the entire population has continuous contact with several domestic animals. Tick attack history is widespread affecting roughly 100% of the population. From March to April 2001, health officials offe...

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Section: Discussionsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 66%

mentioning

confidence: 99%

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Antibodies to Rickettsia rickettsii, Rickettsia typhi, Coxiella burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis among healthy population in Minas Gerais, Brazil

Costa

Brigatte

Greco

2005

Mem. Inst. Oswaldo Cruz

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“…Humans are incidental hosts of these pathogens, and the recent emergence of ehrlichiosis in humans has been associated with changes in ecology, demographics, and host susceptibility. 1 Ehrlichia chaffeensis, [2][3][4] Ehrlichia ewingii, 5,6 and Ehrlichia canis 7,8 cause ehrlichioses of medical and veterinary importance, with E. chaffeensis and E. canis being the primary agents of severe and sometimes fatal human monocytotropic ehrlichiosis (HME) and canine monocytic ehrlichiosis (CME), respectively. E. chaffeensis was first identified as an agent of human disease in 1987 in the United States, 2 whereas globally distributed E. canis was first identified in Africa as early as 1935 9 and in North America in 1962.…”

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confidence: 99%

Detection of Medically Important Ehrlichia by Quantitative Multicolor TaqMan Real-Time Polymerase Chain Reaction of the dsb Gene

Doyle

Labruna

Breitschwerdt

et al. 2005

The Journal of Molecular Diagnostics

211

117

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Ehrlichia species are the etiological agents of emerging and life-threatening tick-borne human zoonoses, in addition to causing serious and fatal infections in companion animals and livestock. We developed the first tricolor TaqMan real-time polymerase chain reaction assay capable of simultaneously detecting and discriminating medically important ehrlichiae in a single reaction. Analytical sensitivity of 50 copies per reaction was attained with templates from Ehrlichia chaffeensis, Ehrlichia ewingii, and Ehrlichia canis by amplifying the genus-specific disulfide bond formation protein gene (dsb). Ehrlichia genus-specific dsb primers amplified DNA from all known Ehrlichia species but not from other rickettsial organisms including Anaplasma platys, Anaplasma phagocytophilum, Rickettsia conorii, or Rickettsia typhi. High species specificity was attained as each species-specific TaqMan probe (E. chaffeensis, E. ewingii, and E. canis) identified homologous templates but did not cross-hybridize with heterologous Ehrlichia templates at concentrations as high as 10 8 copies. Identification of E. chaffeensis, E. ewingii, and E. canis from natural and experimental infections, previously confirmed by polymerase chain reaction and serological or microscopic evidence, demonstrated the comparable specificity and sensitivity of the dsb real-time assay. This assay provides a powerful tool for prospective medical diagnosis for human and canine ehrlichioses and for ecologic and epidemiological studies involving arthropod and mammalian hosts. (J Mol Diagn 2005, 7:504 -510)

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“…Ehrlichia chaffeensis is the agent of human monocytic ehrlichiosis (HME), a zoonotic tickborne disease found in the United States and possibly worldwide [1,2]. This organism is classified in the order Rickettsiales, family Anaplasmataceae, which includes vector-borne, obligate intracellular bacteria that reside within parasitophorous vacuoles [3].…”

Section: Introductionmentioning

confidence: 99%

Development of a p28-based PCR assay for Ehrlichia chaffeensis

Wagner

Bremer

Rikihisa

et al. 2004

Molecular and Cellular Probes

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Detection of Ehrlichia chaffeensis is necessary to study interactions between the parasite and its vertebrate and invertebrate hosts. The purpose of this study was to develop a sensitive, specific PCR assay for E. chaffeensis based on the outer membrane protein gene, p28. Candidate primer sets were identified and ranked based on annealing scores, similarities to three major p28 sequence clusters, dissimilarity to E. canis p30, an ortholog of p28, and the proximities of flanking primer sequences for nested PCR. The relative sensitivities of five optimized single-step and two nested PCR assays were determined, and the most sensitive assay was found to be a single-step PCR that was as much as 1000-fold more sensitive than a standard 16S rDNA-based nested PCR assay. This p28-based PCR assay amplified the target amplicon from isolates representative of all three major clusters of known p28 sequences, and this assay did not amplify template prepared from either of the two species most closely related to E. chaffeensis, E. canis and E. muris. These results indicate that this sensitive, specific and isolate-universal single-step PCR assay will be a useful tool in characterizing the transmission of this important zoonotic pathogen.

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Ehrlichia chaffeensis: a Prototypical Emerging Pathogen

Cited by 120 publications

References 205 publications

Antibodies to Rickettsia rickettsii, Rickettsia typhi, Coxiella burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis among healthy population in Minas Gerais, Brazil

Antibodies to Rickettsia rickettsii, Rickettsia typhi, Coxiella burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis among healthy population in Minas Gerais, Brazil

Detection of Medically Important Ehrlichia by Quantitative Multicolor TaqMan Real-Time Polymerase Chain Reaction of the dsb Gene

Development of a p28-based PCR assay for Ehrlichia chaffeensis

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