Last data update: Apr 29, 2024. (Total: 46658 publications since 2009)
Records 1-30 (of 58 Records) |
Query Trace: Nicholson WL[original query] |
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A mutation associated with resistance to synthetic pyrethroids is widespread in US populations of the tropical lineage of Rhipicephalus sanguineus s.l
Stone NE , Ballard R , Bourgeois RM , Pemberton GL , McDonough RF , Ruby MC , Backus LH , López-Pérez AM , Lemmer D , Koch Z , Brophy M , Paddock CD , Kersh GJ , Nicholson WL , Sahl JW , Busch JD , Salzer JS , Foley JE , Wagner DM . Ticks Tick Borne Dis 2024 15 (4) 102344 The brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.), is an important vector for Rickettsia rickettsii, causative agent of Rocky Mountain spotted fever. Current public health prevention and control efforts to protect people involve preventing tick infestations on domestic animals and in and around houses. Primary prevention tools rely on acaricides, often synthetic pyrethroids (SPs); resistance to this chemical class is widespread in ticks and other arthropods. Rhipicephalus sanguineus s.l. is a complex that likely contains multiple unique species and although the distribution of this complex is global, there are differences in morphology, ecology, and perhaps vector competence among these major lineages. Two major lineages within Rh. sanguineus s.l., commonly referred to as temperate and tropical, have been documented from multiple locations in North America, but are thought to occupy different ecological niches. To evaluate potential acaricide resistance and better define the distributions of the tropical and temperate lineages throughout the US and in northern Mexico, we employed a highly multiplexed amplicon sequencing approach to characterize sequence diversity at: 1) three loci within the voltage-gated sodium channel (VGSC) gene, which contains numerous genetic mutations associated with resistance to SPs; 2) a region of the gamma-aminobutyric acid-gated chloride channel gene (GABA-Cl) containing several mutations associated with dieldrin/fipronil resistance in other species; and 3) three mitochondrial genes (COI, 12S, and 16S). We utilized a geographically diverse set of Rh sanguineus s.l. collected from domestic pets in the US in 2013 and a smaller set of ticks collected from canines in Baja California, Mexico in 2021. We determined that a single nucleotide polymorphism (T2134C) in domain III segment 6 of the VGSC, which has previously been associated with SP resistance in Rh. sanguineus s.l., was widespread and abundant in tropical lineage ticks (>50 %) but absent from the temperate lineage, suggesting that resistance to SPs may be common in the tropical lineage. We found evidence of multiple copies of GABA-Cl in ticks from both lineages, with some copies containing mutations associated with fipronil resistance in other species, but the effects of these patterns on fipronil resistance in Rh. sanguineus s.l. are currently unknown. The tropical lineage was abundant and geographically widespread, accounting for 79 % of analyzed ticks and present at 13/14 collection sites. The temperate and tropical lineages co-occurred in four US states, and as far north as New York. None of the ticks we examined were positive for Rickettsia rickettsii or Rickettsia massiliae. |
Field-collected ticks from Benton County, Arkansas, and prevalence of associated pathogens
Panella NA , Nicholson WL , Komar N , Burkhalter KL , Hughes HR , Theuret DP , Blocher BH , Sexton C , Connelly R , Rothfeldt L , Kenney JL . J Med Entomol 2024 The recovery of a Haemaphysalis longicornis Neumann (Acari: Ixodidae) tick from a dog in Benton County, Arkansas, in 2018 triggered a significant environmental sampling effort in Hobbs State Park Conservation Area. The objective of the investigation was to assess the tick population density and diversity, as well as identify potential tick-borne pathogens that could pose a risk to public health. During a week-long sampling period in August of 2018, a total of 6,154 ticks were collected, with the majority identified as Amblyomma americanum (L), (Acari: Ixodidae) commonly known as the lone star tick. No H. longicornis ticks were found despite the initial detection of this species in the area. This discrepancy highlights the importance of continued monitoring efforts to understand the dynamics of tick populations and their movements. The investigation also focused on pathogen detection, with ticks being pooled by species, age, and sex before being processed with various bioassays. The results revealed the presence of several tick-borne pathogens, including agents associated with ehrlichiosis (n = 12), tularemia (n = 2), and Bourbon virus (BRBV) disease (n = 1), as well as nonpathogenic rickettsial and anaplasmosis organisms. These findings emphasize the importance of public health messaging to raise awareness of the risks associated with exposure to tick-borne pathogens. Prevention measures, such as wearing protective clothing, using insect repellent, and conducting regular tick checks, should be emphasized to reduce the risk of tick-borne diseases. Continued surveillance efforts and research are also essential to improve our understanding of tick-borne disease epidemiology and develop effective control strategies. |
Prevalence and risk factors for Q fever, spotted fever group rickettsioses, and typhus group rickettsioses in a pastoralist community of northern Tanzania, 2016-2017
Moorthy GS , Rubach MP , Maze MJ , Refuerzo RP , Shirima GM , Lukambagire AS , Bodenham RF , Cash-Goldwasser S , Thomas KM , Sakasaka P , Mkenda N , Bowhay TR , Perniciaro JL , Nicholson WL , Kersh GJ , Kazwala RR , Mmbaga BT , Buza JJ , Maro VP , Haydon DT , Crump JA , Halliday JEB . Trop Med Int Health 2024 BACKGROUND: In northern Tanzania, Q fever, spotted fever group (SFG) rickettsioses, and typhus group (TG) rickettsioses are common causes of febrile illness. We sought to describe the prevalence and risk factors for these zoonoses in a pastoralist community. METHODS: Febrile patients ≥2 years old presenting to Endulen Hospital in the Ngorongoro Conservation Area were enrolled from August 2016 through October 2017. Acute and convalescent blood samples were collected, and a questionnaire was administered. Sera were tested by immunofluorescent antibody (IFA) IgG assays using Coxiella burnetii (Phase II), Rickettsia africae, and Rickettsia typhi antigens. Serologic evidence of exposure was defined by an IFA titre ≥1:64; probable cases by an acute IFA titre ≥1:128; and confirmed cases by a ≥4-fold rise in titre between samples. Risk factors for exposure and acute case status were evaluated. RESULTS: Of 228 participants, 99 (43.4%) were male and the median (interquartile range) age was 27 (16-41) years. Among these, 117 (51.3%) had C. burnetii exposure, 74 (32.5%) had probable Q fever, 176 (77.2%) had SFG Rickettsia exposure, 134 (58.8%) had probable SFG rickettsioses, 11 (4.8%) had TG Rickettsia exposure, and 4 (1.8%) had probable TG rickettsioses. Of 146 participants with paired sera, 1 (0.5%) had confirmed Q fever, 8 (5.5%) had confirmed SFG rickettsioses, and none had confirmed TG rickettsioses. Livestock slaughter was associated with acute Q fever (adjusted odds ratio [OR] 2.54, 95% confidence interval [CI] 1.38-4.76) and sheep slaughter with SFG rickettsioses case (OR 4.63, 95% CI 1.08-23.50). DISCUSSION: Acute Q fever and SFG rickettsioses were detected in participants with febrile illness. Exposures to C. burnetii and to SFG Rickettsia were highly prevalent, and interactions with livestock were associated with increased odds of illness with both pathogens. Further characterisation of the burden and risks for these diseases is warranted. |
Acquisition of Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) by Haemaphysalis longicornis (Acari: Ixodidae) through co-feeding with infected Dermacentor variabilis (Acari: Ixodidae) in the laboratory
Johnson B , Snellgrove AN , McBride SE , Hartzer K , Levin ML , Nicholson WL . J Med Entomol 2023 60 (6) 1380-1387 Haemaphysalis longicornis (Neumann) is an invasive ixodid tick originating from eastern Asia which recently has become established in the United States. In its native range, this tick can transmit several pathogens to animals and humans, but little is known about its ability to acquire and transmit pathogens native to the United States. Geographic overlap with ticks such as Dermacentor variabilis (Say), a known vector of Rickettsia rickettsii, makes investigation into the interactions between H. longicornis and D. variabilis of interest to the public health community. Previous studies have shown that H. longicornis can serve as a competent vector of R. rickettsii under laboratory settings, but there is little information on its ability to acquire this pathogen via other biologically relevant routes, such as co-feeding. Here, we assess the ability of H. longicornis nymphs to acquire R. rickettsii through co-feeding with infected D. variabilis adults on a vertebrate animal model under laboratory conditions. The median infection prevalence in engorged H. longicornis nymphs across 8 cohorts was 0% with an interquartile range (IQR) of 4.13%. Following transstadial transmission, the median infection prevalence in flat females was 0.7% (IQR = 2.4%). Our results show that co-feeding transmission occurs at low levels in the laboratory between these 2 species. However, based on the relatively low transmission rates, this may not be a likely mechanism of R. rickettsii introduction to H. longicornis. |
Investigating the etiology of acute febrile illness: a prospective clinic-based study in Uganda
Kigozi BK , Kharod GA , Bukenya H , Shadomy SV , Haberling DL , Stoddard RA , Galloway RL , Tushabe P , Nankya A , Nsibambi T , Mbidde EK , Lutwama JJ , Perniciaro JL , Nicholson WL , Bower WA , Bwogi J , Blaney DD . BMC Infect Dis 2023 23 (1) 411 BACKGROUND: Historically, malaria has been the predominant cause of acute febrile illness (AFI) in sub-Saharan Africa. However, during the last two decades, malaria incidence has declined due to concerted public health control efforts, including the widespread use of rapid diagnostic tests leading to increased recognition of non-malarial AFI etiologies. Our understanding of non-malarial AFI is limited due to lack of laboratory diagnostic capacity. We aimed to determine the etiology of AFI in three distinct regions of Uganda. METHODS: A prospective clinic-based study that enrolled participants from April 2011 to January 2013 using standard diagnostic tests. Participant recruitment was from St. Paul's Health Centre (HC) IV, Ndejje HC IV, and Adumi HC IV in the western, central and northern regions, which differ by climate, environment, and population density. A Pearson's chi-square test was used to evaluate categorical variables, while a two-sample t-test and Krukalis-Wallis test were used for continuous variables. RESULTS: Of the 1281 participants, 450 (35.1%), 382 (29.8%), and 449 (35.1%) were recruited from the western, central, and northern regions, respectively. The median age (range) was 18 (2-93) years; 717 (56%) of the participants were female. At least one AFI pathogen was identified in 1054 (82.3%) participants; one or more non-malarial AFI pathogens were identified in 894 (69.8%) participants. The non-malarial AFI pathogens identified were chikungunya virus, 716 (55.9%); Spotted Fever Group rickettsia (SFGR), 336 (26.2%) and Typhus Group rickettsia (TGR), 97 (7.6%); typhoid fever (TF), 74 (5.8%); West Nile virus, 7 (0.5%); dengue virus, 10 (0.8%) and leptospirosis, 2 (0.2%) cases. No cases of brucellosis were identified. Malaria was diagnosed either concurrently or alone in 404 (31.5%) and 160 (12.5%) participants, respectively. In 227 (17.7%) participants, no cause of infection was identified. There were statistically significant differences in the occurrence and distribution of TF, TGR and SFGR, with TF and TGR observed more frequently in the western region (p = 0.001; p < 0.001) while SFGR in the northern region (p < 0.001). CONCLUSION: Malaria, arboviral infections, and rickettsioses are major causes of AFI in Uganda. Development of a Multiplexed Point-of-Care test would help identify the etiology of non-malarial AFI in regions with high AFI rates. |
Using next generation sequencing for molecular detection and differentiation of Anaplasma phagocytophilum variants from host seeking Ixodes scapularis ticks in the United States.
Hojgaard A , Osikowicz LM , Rizzo MF , Ayres BN , Nicholson WL , Eisen RJ . Ticks Tick Borne Dis 2022 13 (6) 102041 Anaplasmosis is increasingly common in the United States, with cases being reported over an expanding geographic area. To monitor for changes in risk of human infection, the U.S. Centers for Disease Control and Prevention monitors the distribution and abundance of host-seeking vector ticks (Ixodes scapularis and Ixodes pacificus) and their infection with Anaplasma phagocytophilum. While several variants of A. phagocytophilum circulate in I. scapularis, only the human-active variant (Ap-ha) appears to be pathogenic in humans. Failure to differentiate between human and non-human variants may artificially inflate estimates of the risk of human infection. Efforts to differentiate the Ap-ha variant from the deer variant (Ap-V1) in ticks typically rely on traditional PCR assays coupled with sequencing of PCR products. However, laboratories are increasingly turning to Next Generation Sequencing (NGS) to increase testing efficiency, retain high sensitivity, and increase specificity compared with traditional PCR assays. We describe a new NGS assay with novel targets that accurately segregate the Ap-ha variant from other non-human variants and further identify unique clades within the human and non-human variants. Recognizing that not all investigators have access to NGS technology, we also developed a PCR assay based on one of the novel targets so that variants can be visualized using agarose gel electrophoresis without the need for subsequent sequencing. Such an assay may be used to improve estimates of human risk of developing anaplasmosis in North America. |
Rickettsial agents detected in ixodid ticks (Acari: Ixodidae) collected from Sus scrofa (Artiodactyla: Suidae) in Florida and South Carolina
Ayres BN , James AM , Wehtje ME , Nicholson WL . J Entomol Sci 2022 57 (3) 351-362 Feral swine, Sus scrofa L., have become a nuisance to landowners across the United States by damaging agriculture, property, and ecosystems. Additionally, these animals have been found to host various ixodid ticks including Amblyomma americanum (L.), Amblyomma maculatum Koch, Dermacentor variabilis (Say), and Ixodes scapularis Say, which can maintain and transmit several rickettsial pathogens to livestock, wildlife, and humans. Though previous research has identified the maintenance cycle of several rickettsial pathogens in ticks and native wildlife, little is known about the role S. scrofa plays in supporting ixodid ticks and the pathogens these ticks could be harboring. This study sought to identify rickettsial agents (Rickettsiales: Anaplasmataceae and Rickettsiaceae) in ticks collected from S. scrofa obtained in Florida and South Carolina. Overall, ticks from four species (A. americanum, D. variabilis, I. scapularis, and A. maculatum) totaling 258 collected individuals were obtained from S. scrofa (n = 45). We found an Ehrlichia chaffeensis Anderson et al. infection prevalence in A. americanum of 2.7% and 2.9% in Florida and South Carolina, respectively. A Rickettsia parkeri Lackman et al. prevalence of 100% and 33% was found in A. maculatum from Florida and South Carolina, respectively. Additionally, a 0.9% infection prevalence of R. parkeri was identified in A. americanum collected in South Carolina. A 1.9% Ehrlichia ewingii Anderson et al. infection prevalence was documented in collected A. americanum in South Carolina. Further studies are warranted to better understand the role S. scrofa plays in the natural maintenance of rickettsial agents in various regions of the United States. © 2022 Georgia Entomological Society Inc.. All rights reserved. |
First detection of human pathogenic variant of Anaplasma phagocytophilum in field-collected Haemaphysalis longicornis, Pennsylvania, USA.
Price KJ , Ayres BN , Maes SE , Witmier BJ , Chapman HA , Coder BL , Boyer CN , Eisen RJ , Nicholson WL . Zoonoses Public Health 2021 69 (2) 143-148 The Asian longhorned tick, Haemaphysalis longicornis, an invasive species associated with human pathogens, has spread rapidly across the eastern USA. Questing H. longicornis ticks recovered from active surveillance conducted from 1 May to 6 September, 2019 throughout Pennsylvania were tested for rickettsial pathogens. Of 265 ticks tested by PCR for pathogens, 4 (1.5%) were positive for Anaplasma phagocytophilum. Sequence analysis of the 16S rRNA gene confirmed two positives as A. phagocytophilum-human agent variant. This is the first reported detection of A. phagocytophilum-human pathogenic strain DNA in exotic H. longicornis collected in the USA. |
Incidence Estimates of Acute Q Fever and Spotted Fever Group Rickettsioses, Kilimanjaro, Tanzania, from 2007 to 2008 and from 2012 to 2014
Pisharody S , Rubach MP , Carugati M , Nicholson WL , Perniciaro JL , Biggs HM , Maze MJ , Hertz JT , Halliday JEB , Allan KJ , Mmbaga BT , Saganda W , Lwezaula BF , Kazwala RR , Cleaveland S , Maro VP , Crump JA . Am J Trop Med Hyg 2021 106 (2) 494-503 Q fever and spotted fever group rickettsioses (SFGR) are common causes of severe febrile illness in northern Tanzania. Incidence estimates are needed to characterize the disease burden. Using hybrid surveillance-coupling case-finding at two referral hospitals and healthcare utilization data-we estimated the incidences of acute Q fever and SFGR in Moshi, Kilimanjaro, Tanzania, from 2007 to 2008 and from 2012 to 2014. Cases were defined as fever and a four-fold or greater increase in antibody titers of acute and convalescent paired sera according to the indirect immunofluorescence assay of Coxiella burnetii phase II antigen for acute Q fever and Rickettsia conorii (2007-2008) or Rickettsia africae (2012-2014) antigens for SFGR. Healthcare utilization data were used to adjust for underascertainment of cases by sentinel surveillance. For 2007 to 2008, among 589 febrile participants, 16 (4.7%) of 344 and 27 (8.8%) of 307 participants with paired serology had Q fever and SFGR, respectively. Adjusted annual incidence estimates of Q fever and SFGR were 80 (uncertainty range, 20-454) and 147 (uncertainty range, 52-645) per 100,000 persons, respectively. For 2012 to 2014, among 1,114 febrile participants, 52 (8.1%) and 57 (8.9%) of 641 participants with paired serology had Q fever and SFGR, respectively. Adjusted annual incidence estimates of Q fever and SFGR were 56 (uncertainty range, 24-163) and 75 (uncertainty range, 34-176) per 100,000 persons, respectively. We found substantial incidences of acute Q fever and SFGR in northern Tanzania during both study periods. To our knowledge, these are the first incidence estimates of either disease in sub-Saharan Africa. Our findings suggest that control measures for these infections warrant consideration. |
First record of the Asian longhorned tick Haemaphysalis longicornis in Missouri
Roberts L , Brauer B , Nicholson WL , Ayres BN , Thompson KR , Claborn DM . J Am Mosq Control Assoc 2021 37 (4) 296-297 The Asian longhorned tick, Haemaphysalis longicornis, is an invasive species, originally from eastern Asia, and was first reported in the USA in New Jersey. It is now reported in several eastern states. In 2018, researchers reported H. longicornis in northwest Arkansas (Benton County). This tick species is a proven vector of livestock and human diseases, which prompted the current survey of ticks in southwest Missouri. A tick drag in Greene County, Missouri, produced 2 H. longicornis nymphs on June 9, 2021. This is the first report of this species for both the state and county. |
Established population of the Gulf Coast tick, Amblyomma maculatum (Acari: Ixodidae), infected with Rickettsia parkeri (Rickettsiales: Rickettsiaceae), in Connecticut
Molaei G , Little EAH , Khalil N , Ayres BN , Nicholson WL , Paddock CD . J Med Entomol 2021 58 (3) 1459-1462 We identified an established population of the Gulf Coast tick (Amblyomma maculatum Koch) infected with Rickettsia parkeri in Connecticut, representing the northernmost range limit of this medically relevant tick species. Our finding highlights the importance of tick surveillance and public health challenges posed by geographic expansion of tick vectors and their pathogens. |
Risk factors for and seroprevalence of tickborne zoonotic diseases among livestock owners, Kazakhstan
Head JR , Bumburidi Y , Mirzabekova G , Rakhimov K , Dzhumankulov M , Salyer SJ , Knust B , Berezovskiy D , Kulatayeva M , Zhetibaev S , Shoemaker T , Nicholson WL , Moffett D . Emerg Infect Dis 2020 26 (1) 70-80 Crimean-Congo hemorrhagic fever (CCHF), Q fever, and Lyme disease are endemic to southern Kazakhstan, but population-based serosurveys are lacking. We assessed risk factors and seroprevalence of these zoonoses and conducted surveys for CCHF-related knowledge, attitudes, and practices in the Zhambyl region of Kazakhstan. Weighted seroprevalence for CCHF among all participants was 1.2%, increasing to 3.4% in villages with a known history of CCHF circulation. Weighted seroprevalence was 2.4% for Lyme disease and 1.3% for Q fever. We found evidence of CCHF virus circulation in areas not known to harbor the virus. We noted that activities that put persons at high risk for zoonotic or tickborne disease also were risk factors for seropositivity. However, recognition of the role of livestock in disease transmission and use of personal protective equipment when performing high-risk activities were low among participants. |
Sensitivity of C-reactive protein for the identification of patients with laboratory-confirmed bacterial infections in northern Tanzania
Althaus T , Lubell Y , Maro VP , Mmbaga BT , Lwezaula B , Halleux C , Biggs HM , Galloway RL , Stoddard RA , Perniciaro JL , Nicholson WL , Doyle K , Olliaro P , Crump JA , Rubach MP . Trop Med Int Health 2019 25 (3) 291-300 OBJECTIVE: Identifying febrile patients requiring antibacterial treatment is challenging, particularly in low-resource settings. In Southeast Asia, C-reactive protein (CRP) has been demonstrated to be highly sensitive and moderately specific in detecting bacterial infections, and to safely reduce unnecessary antibacterial prescriptions in primary care. As evidence is scant in sub-Saharan Africa, we assessed the sensitivity of CRP in identifying serious bacterial infections in Tanzania. METHODS: Samples were obtained from inpatients and outpatients in a prospective febrile illness study at two hospitals in Moshi, Tanzania, 2011-2014. Bacterial bloodstream infections (BSI) were established by blood culture, and bacterial zoonotic infections were defined by >/=4-fold rise in antibody titer between acute and convalescent sera. The sensitivity of CRP in identifying bacterial infections was estimated using thresholds of 10, 20, and 40 mg/L. Specificity was not assessed because determining false positive CRP results was limited by the lack of diagnostic testing to confirm non-bacterial etiologies and because ascertaining true negative cases was limited by the imperfect sensitivity of the diagnostic tests used to identify bacterial infections. RESULTS: Among 235 febrile outpatients and 569 febrile inpatients evaluated, 31 (3.9%) had a bacterial BSI and 61 (7.6%) had a bacterial zoonosis. Median (interquartile range) CRP values were 173 (80-315) mg/L in bacterial BSI, and 108 (31-208) mg/L in bacterial zoonoses. The sensitivity (95% Confidence Intervals) of CRP was 97% (83-99%), 94% (79-98%), 90% (74-97%) for identifying bacterial BSI, and 87% (76-93%), 82% (71-90%), 72% (60-82%) for bacterial zoonoses, using thresholds of 10, 20 and 40mg/L respectively. CONCLUSION: CRP was moderately sensitive for bacterial zoonoses and highly sensitive for identifying BSIs. Based on these results, operational studies are warranted to assess the safety and clinical utility of CRP for the management of non-malaria febrile illness at first-level health facilities in sub-Saharan Africa. |
Bourbon virus in wild and domestic animals, Missouri, USA, 2012-2013
Jackson KC , Gidlewski T , Root JJ , Bosco-Lauth AM , Lash RR , Harmon JR , Brault AC , Panella NA , Nicholson WL , Komar N . Emerg Infect Dis 2019 25 (9) 1752-1753 Since its recent discovery, Bourbon virus has been isolated from a human and ticks. To assess exposure of potential vertebrate reservoirs, we assayed banked serum and plasma samples from wildlife and domestic animals in Missouri, USA, for Bourbon virus-neutralizing antibodies. We detected high seroprevalence in raccoons (50%) and white-tailed deer (86%). |
Diversity and structure of the bacterial microbiome of the American dog tick, Dermacentor variabilis, is dominated by the endosymbiont Francisella
Travanty NV , Ponnusamy L , Kakumanu ML , Nicholson WL , Apperson CS . Symbiosis 2019 79 (3) 239-250 The American dog tick, Dermacentor variabilis Say, is the principal vector of spotted fever group rickettsiae that cause illness in people. Because the composition and structure of microbial communities in D. variabilis are poorly understood, we conducted high-throughput amplicon sequencing of the 16S rRNA gene to characterize the bacterial communities of adult D. variabilis ticks collected from field populations in North Carolina. Sequence analyses were performed using QIIME 2 with the DADA2 plugin and taxonomic assignments using the Greengenes database. After quality filtering and rarefaction, the bacterial DNA sequences were assigned to 432 operational taxonomic units (OTUs) and were dominated by a single OTU classified as Francisella spp. Subsequent cloning, sequencing and phylogenic analysis of nearly full length 16S rRNA gene fragments revealed that most Francisella were similar to Francisella-like endosymbionts (FLEs) of D. variabilis reported previously. One cloned Francisella, however, was genetically distinct and more related to the FLE of D. occidentalis. The core microbiome of D. variabilis was comprised of Francisella spp., Sphingomonas spp., Delftia spp., and Hymenobacter spp. The taxonomic resolution and detection of less abundant bacterial taxa, including Rickettsia, are discussed. Alpha diversity metrics revealed lower bacterial community diversity in females. Beta-diversity also distinguished the composition of female bacterial communities from those of males. These findings advance current knowledge of the microbial ecology and structure and composition of D. variabilis microbiome and sets the foundation for further studies to determine the influence of microbiota on vector susceptibility to pathogens. |
Seroprevalence of spotted fever group rickettsiae in canines along the United States-Mexico border
Pieracci EG , De La Rosa JDP , Rubio DL , Perales MES , Drexler NA , Nicholson WL , De La Rosa JJP , Chung IH , Kato C , Barton Behravesh C , Enriquez MAG , Roldan JFG , Villarino ME . Zoonoses Public Health 2019 66 (8) 918-926 Portions of northern Mexico are experiencing a re-emergence of Rocky Mountain spotted fever (RMSF), a tickborne disease caused by Rickettsia rickettsii, a member of the spotted fever group of rickettsiae (SFGR). Infection with R. rickettsii can result in serious and life-threatening illness in people and dogs. Canine seroprevalence has been used as a sentinel for human RMSF in previous studies. This study aims to quantify SFGR seroprevalence in canines in three northern Mexican states and identify risk factors associated with seropositivity. A total of 1,136 serum samples and 942 ticks were obtained from dogs participating in government sterilization campaigns and from animal control facilities in 14 Mexican cities in three states. SFGR antibodies were detected using indirect immunofluorescence antibody assays at titre values >/=1/64. Six per cent (69 dogs) showed antibodies to SFGR, with the highest seroprevalence reported in Baja California (12%), Coahuila (4%) and Sonora (4%). Dogs from Baja California had three times higher odds of having SFGR antibodies compared to dogs from Sonora (OR = 3.38, 95% CI, 1.81-6.37). Roughly one quarter (25%) of surveyed dogs were parasitized by ticks (Rhipicephalus sanguineus sensu lato) at the time of sample collection. A portion of collected ticks were tested for rickettsial DNA using polymerase chain reaction. Positive samples were then sequenced, showing evidence of SFGR including R. massiliae, R. parkeri and R. rickettsii. Dogs that spent the majority of time on the street, such as free-roaming or community-owned dogs, showed a greater risk of tick infestation, seropositivity, bearing seropositive ticks, and may play a pivotal role in the spread of SFGR among communities. Estimating the seroprevalence of SFGR in the canine population can help public health campaigns target high-risk communities for interventions to reduce human RMSF cases. |
Reported county-level distribution of the American dog tick (Acari: Ixodidae) in the contiguous United States
Lehane A , Parise C , Evans C , Beati L , Nicholson WL , Eisen RJ . J Med Entomol 2019 57 (1) 131-155 In the United States, tick-borne diseases are increasing in incidence and cases are reported over an expanding geographical area. Avoiding tick bites is a key strategy in tick-borne disease prevention, and this requires current and accurate information on where humans are at risk for exposure to ticks. Based on a review of published literature and records in the U.S. National Tick Collection and National Ecological Observatory Network databases, we compiled an updated county-level map showing the reported distribution of the American dog tick, Dermacentor variabilis (Say). We show that this vector of the bacterial agents causing Rocky Mountain spotted fever and tularemia is widely distributed, with records derived from 45 states across the contiguous United States. However, within these states, county-level records of established tick populations are limited. Relative to the range of suitable habitat for this tick, our data imply that D. variabilis is currently underreported in the peer-reviewed literature, highlighting a need for improved surveillance and documentation of existing tick records. |
Serologic assessment for exposure to spotted fever group rickettsiae in dogs in the Arizona-Sonora border region
Yaglom HD , Nicholson WL , Casal M , Nieto NC , Adams L . Zoonoses Public Health 2018 65 (8) 984-992 Rocky Mountain spotted fever (RMSF) is a severe tick-borne rickettsial illness. In the south-western United States and Mexico, RMSF displays unique epidemiologic and ecologic characteristics, including Rhipicephalus sanguineus sensu lato (brown dog tick) as the primary vector. Expansion and spread of the disease from hyperendemic regions of Arizona or Mexico to new areas is a key public health concern. Dogs are thought to play an important role in the emergence and circulation of R. rickettsii in these regions and are often one of earliest indicators of RMSF presence. A canine serosurvey was conducted in 2015 among owned and stray dogs at rabies clinic and animal shelters in three southern Arizona counties where RMSF had not previously been identified. Of the 217 dogs sampled, 11 (5.1%) tested positive for spotted fever group rickettsia (SFGR) IgG antibodies, with seropositivity ranging from 2.9% to 12.2% across the three counties. Large dogs were significantly more likely than small dogs to have positive titres reactive with R. rickettsii; no additional statistically significant relationships were observed between seropositivity of canine age, sex, neuter or ownership status. In addition, 17 (7.8%) dogs had ticks attached at the time of sampling, and stray dogs were significantly more likely to have ticks present than owned dogs (p < 0.001). All 57 ticks collected were identified as Rh. sanguineus s.l., and four (7%) had DNA evidence of genera-wide Rickettsia species. The results of this project demonstrated canine seroprevalence levels lower than those previously reported from dogs in highly endemic areas, indicating a low risk of SFGR transmission to humans in the southern Arizona border region at this time. Continued surveillance is critical to identify SFGR emergence in new geographic regions and to inform prevention efforts for humans and dogs in those areas. |
Prevalence of Rickettsia Species (Rickettsiales: Rickettsiaceae) in Dermacentor variabilis Ticks (Acari: Ixodidae) in North Carolina.
Kakumanu ML , Ponnusamy L , Sutton H , Meshnick SR , Nicholson WL , Apperson CS . J Med Entomol 2018 55 (5) 1284-1291 The American dog tick, Dermacentor variabilis (Say), is a vector of spotted fever group (SFG) rickettsiae, including Rickettsia rickettsii the causative organism of Rocky Mountain spotted fever (RMSF). In North Carolina, SFG rickettsioses (including RMSF) are a leading cause of tick-borne illness. Knowledge of the infection rate and geographic distribution of D. variabilis ticks infected with Rickettsia spp. provides information on the spatial distribution of public health risk. Accordingly, we extracted genomic DNA from adult D. variabilis collected from field habitats in 32 North Carolina counties from 2009 to 2013. A nested PCR assay of the 23S-5S intergenic spacer (IGS) region of Rickettsia coupled with reverse line blot hybridization (RLBH) with species-specific probes was used to detect and identify rickettsiae to species. Approximately half of the 532 tick DNA samples exhibited a band of the expected size on agarose gels, indicating infection with Rickettsia spp. RLBH analyses showed R. amblyommatis (formerly 'Candidatus R. amblyommii'), R. parkeri, and R. montanensis were predominant, while other Rickettsia species detected included R. conorii-like, R. massiliae, R. rhipicephali, R. canadensis, R. bellii, and some unknown Rickettsia spp. Some ticks were infected with more than one Rickettsia species. Notably, several Rickettsia-positive ticks harbored R. rickettsii. DNA sequencing was performed on a portion of the 23S-5S IGS amplicons and the results were concordant with RLB assay results. We conclude that Rickettsia spp. are common in D. variabilis in North Carolina. Geographic patterns in the occurrence of Rickettsia-infected D. variabilis ticks across the counties sampled are discussed. |
Bourbon virus in field-collected ticks, Missouri, USA
Savage HM , Burkhalter KL , Godsey MS Jr , Panella NA , Ashley DC , Nicholson WL , Lambert AJ . Emerg Infect Dis 2017 23 (12) 2017-2022 Bourbon virus (BRBV) was first isolated in 2014 from a resident of Bourbon County, Kansas, USA, who died of the infection. In 2015, an ill Payne County, Oklahoma, resident tested positive for antibodies to BRBV, before fully recovering. We retrospectively tested for BRBV in 39,096 ticks from northwestern Missouri, located 240 km from Bourbon County, Kansas. We detected BRBV in 3 pools of Amblyomma americanum (L.) ticks: 1 pool of male adults and 2 pools of nymphs. Detection of BRBV in A. americanum, a species that is aggressive, feeds on humans, and is abundant in Kansas and Oklahoma, supports the premise that A. americanum is a vector of BRBV to humans. BRBV has not been detected in nonhuman vertebrates, and its natural history remains largely unknown. |
Isolation and characterization of a unique strain of Rickettsia parkeri associated with the hard tick Dermacentor parumapertus Neumann in the western United States.
Paddock CD , Allerdice ME , Karpathy SE , Nicholson WL , Levin ML , Smith TC , Becker T , Delph RJ , Knight RN , Ritter JM , Sanders JH , Goddard J . Appl Environ Microbiol 2017 83 (9) In 1953, investigators at the Rocky Mountain Laboratories in Hamilton, Montana, described the isolation of a spotted fever group Rickettsia (SFGR) species from Dermacentor parumapertus collected from black-tailed jackrabbits (Lepus californicus) in northern Nevada. Several decades later, investigators characterized this SFGR by using mouse serotyping methods and determined that it represented a distinct rickettsial serotype, related closely to Rickettsia parkeri; nonetheless, the parumapertus agent was not further characterized or studied. No extant isolates of the parumapertus agent remain in any rickettsial culture collection around the world which precludes contemporary phylogenetic placement of this enigmatic SFGR. To rediscover the parumapertus agent, adult-stage D. parumapertus ticks were collected from black-tailed jackrabbits shot or encountered as road-kills in Arizona, Utah, or Texas during 2011-2016. A total of 339 ticks were collected and evaluated for infection with Rickettsia species. From 112 D. parumapertus collected in south Texas, 16 (14.3%) contained partial ompA sequences with closest identity (99.6%) to Rickettsia sp. Atlantic rainforest, a recently identified pathogenic SFGR that causes a mild rickettsiosis in several states of Brazil. A pure isolate, designated strain Black Gap, was cultivated in Vero E6 cells and sequence analysis of the rrs, gltA, sca0, sca5 and sca4 genes also revealed closest genetic identity to Rickettsia sp. Atlantic rainforest. Phylogenetic analysis of the five concatenated rickettsial genes place Rickettsia sp. Black Gap and Rickettsia sp. Atlantic rainforest with R. parkeri in a distinct and well-supported clade.Importance. We suggest that Rickettsia sp. Black Gap and Rickettsia sp. Atlantic rainforest represent nearly identical strains of R. parkeri, and that Rickettsia sp. Black Gap, or a very similar strain of R. parkeri, represents the parumapertus agent. Close genetic relatedness among these taxa, as well as the response of guinea pigs infected with Black Gap strain, suggest that R. parkeri Black Gap could cause disease in humans. The identification of this organism could also account, at least in part, for remarkable differences in severity ascribed to RMSF among various regions of the American West during the early 20th century. We suggest that wide variation in case-fatality rates attributed to RMSF could have occurred by the inadvertent inclusion of cases of milder disease caused by R. parkeri Black Gap. |
Prevalence and clinical presentation of Rickettsia, Coxiella, Leptospira, Bartonella and chikungunya virus infections among hospital-based febrile patients from December 2008 to November 2009 in Bangladesh
Faruque LI , Zaman RU , Gurley ES , Massung RF , Alamgir AS , Galloway RL , Powers AM , Bai Y , Kosoy M , Nicholson WL , Rahman M , Luby SP . BMC Infect Dis 2017 17 (1) 141 BACKGROUND: We conducted a study to identify Rickettsia, Coxiella, Leptospira, Bartonella, and Chikungunya virus infections among febrile patients presenting at hospitals in Bangladesh. METHODS: We collected blood samples from patients at six tertiary hospitals from December 2008 to November 2009 and performed laboratory tests at the United States Centers for Disease Control and Prevention (CDC). RESULTS: Out of 720 enrolled patients, 263 (37%) were infected with Rickettsia; 132 patients had immunofluorescence antibody titer >64 against spotted fever, 63 patients against scrub typhus fever and 10 patients against typhus fever. Ten patients were identified with Coxiella. We isolated Leptospira from two patients and Bartonella from one patient. Ten patients had antibodies against Chikungunya virus. The proportion of patients who died was higher with rickettsial fever (5%) compared to those without a diagnosis of rickettsial infection (2%). None of the patients were initially diagnosed with rickettsial fever. CONCLUSIONS: Rickettsial infections are frequent yet under-recognized cause of febrile illness in Bangladesh. Clinical guidelines should be revised so that local clinicians can diagnose rickettsial infections and provide appropriate drug treatment. |
Rickettsia amblyommatis sp. nov., a spotted fever group Rickettsia associated with multiple species of Amblyomma ticks in North, Central and South America
Karpathy SE , Slater KS , Goldsmith CS , Nicholson WL , Paddock CD . Int J Syst Evol Microbiol 2016 66 (12) 5236-5243 In 1973, investigators isolated a rickettsial organism, designated strain WB-8-2T, from an adult Amblyomma americanum tick collected at Land Between the Lakes National Recreation Area, TN, USA. This organism is now recognized as highly prevalent in A. americanum, as well as several other Amblyomma species found throughout the Western hemisphere. It has been suggested that cross-reactivity to WB-8-2T and similar strains contributes to the increasing number of spotted fever cases reported in the USA. In 1995, investigators provided preliminary evidence that this strain, as well as another strain from Missouri, represented a distinct taxonomic unit within the genus Rickettsia by evaluating sequences of the 16S rRNA and 17 kDa protein genes. However, the bacterium was never formally named, despite the use of the designation 'Rickettsia amblyommii' and later 'Candidatus Rickettsia amblyommii', for more than 20 years in the scientific literature. Herein, we provide additional molecular evidence to identify strain WB-8-2T as a representative strain of a unique rickettsial species and present a formal description for the species, with the proposed name modified to Rickettsia amblyommatis sp. nov. to conform to the International Code of Nomenclature of Prokaryotes. We also establish a pure culture of strain WB-8-2T and designate it as the type strain for the species. The type strain is WB-8-2T (=CRIRC RAM004T=CSURP2882T). |
Diagnosis and management of tickborne rickettsial iseases: Rocky mountain spotted fever and other spotted fever group rickettsioses, ehrlichioses, and anaplasmosis - United States
Biggs HM , Behravesh CB , Bradley KK , Dahlgren FS , Drexler NA , Dumler JS , Folk SM , Kato CY , Lash RR , Levin ML , Massung RF , Nadelman RB , Nicholson WL , Paddock CD , Pritt BS , Traeger MS . MMWR Recomm Rep 2016 65 (2) 1-44 Tickborne rickettsial diseases continue to cause severe illness and death in otherwise healthy adults and children, despite the availability of low-cost, effective antibacterial therapy. Recognition early in the clinical course is critical because this is the period when antibacterial therapy is most effective. Early signs and symptoms of these illnesses are nonspecific or mimic other illnesses, which can make diagnosis challenging. Previously undescribed tickborne rickettsial diseases continue to be recognized, and since 2004, three additional agents have been described as causes of human disease in the United States: Rickettsia parkeri, Ehrlichia muris-like agent, and Rickettsia species 364D. This report updates the 2006 CDC recommendations on the diagnosis and management of tickborne rickettsial diseases in the United States and includes information on the practical aspects of epidemiology, clinical assessment, treatment, laboratory diagnosis, and prevention of tickborne rickettsial diseases. The CDC Rickettsial Zoonoses Branch, in consultation with external clinical and academic specialists and public health professionals, developed this report to assist health care providers and public health professionals to 1) recognize key epidemiologic features and clinical manifestations of tickborne rickettsial diseases, 2) recognize that doxycycline is the treatment of choice for suspected tickborne rickettsial diseases in adults and children, 3) understand that early empiric antibacterial therapy can prevent severe disease and death, 4) request the appropriate confirmatory diagnostic tests and understand their usefulness and limitations, and 5) report probable and confirmed cases of tickborne rickettsial diseases to public health authorities. |
Surveillance for Heartland virus (Bunyaviridae: Phlebovirus) in Missouri during 2013: First detection of virus in adults of Amblyomma americanum (Acari: Ixodidae)
Savage HM , Godsey MS Jr , Panella NA , Burkhalter KL , Ashley DC , Lash RR , Ramsay B , Patterson T , Nicholson WL . J Med Entomol 2016 53 (3) 607-612 During 2013, we collected and tested ticks for Heartland virus (HRTV), a recently described human pathogen in the genus Phlebovirus (Bunyaviridae), from six sites in northwestern Missouri. Five sites were properties owned by HRTV patients, and the sixth was a conservation area that yielded virus in ticks during 2012. We collected 39,096 ticks representing five species; however, two species, Amblyomma americanum (L.) (97.6%) and Dermacentor variabilis (Say) (2.3%), accounted for nearly all ticks collected. We detected 60 HRTV-positive tick pools and all were composed of A. americanum: 53 pools of nymphs, six pools of male adults, and one pool of female adults. This is the first record of HRTV in adult ticks. Virus was detected at five properties that yielded A. americanum ticks, including properties owned by four of five patients. Virus was detected at two sites that yielded virus in 2012. Detection of virus in multiple years indicates that the virus persists in ticks within a relatively small geographic area, although infection rates (IR) may vary greatly among sites and between years at a site. IR per 1,000 A. americanumin northwestern Missouri during the April-July 2013 study period were as follows: all adults, IR = 1.13; adult females, IR = 0.33; adult males, IR = 1.90; and nymphs, IR = 1.79. The IR in nymphs, the stage with the largest data set, corresponds to 1/559 infected ticks. Having robust estimates of IR in various stages for A. americanum should lead to more accurate public health messaging and a better understanding of virus transmission. |
Incident tick-borne infections in a cohort of North Carolina outdoor workers
Wallace JW , Nicholson WL , Perniciaro JL , Vaughn MF , Funkhouser S , Juliano JJ , Lee S , Kakumanu ML , Ponnusamy L , Apperson CS , Meshnick SR . Vector Borne Zoonotic Dis 2016 16 (5) 302-8 Tick-borne diseases cause substantial morbidity throughout the United States, and North Carolina has a high incidence of spotted fever rickettsioses and ehrlichiosis, with sporadic cases of Lyme disease. The occupational risk of tick-borne infections among outdoor workers is high, particularly those working on publicly managed lands. This study identified incident tick-borne infections and examined seroconversion risk factors among a cohort of North Carolina outdoor workers. Workers from the North Carolina State Divisions of Forestry, Parks and Recreation, and Wildlife (n = 159) were followed for 2 years in a randomized controlled trial evaluating the effectiveness of long-lasting permethrin-impregnated clothing. Antibody titers against Rickettsia parkeri, Rickettsia rickettsii, "Rickettsia amblyommii," and Ehrlichia chaffeensis were measured at baseline (n = 130), after 1 year (n = 82), and after 2 years (n = 73). Titers against Borrelia burgdorferi were measured at baseline and after 2 years (n = 90). Baseline seroprevalence, defined as indirect immunofluorescence antibody titers of 1/128 or greater, was R. parkeri (24%), R. rickettsii (19%), "R. amblyommii" (12%), and E. chaffeensis (4%). Incident infection was defined as a fourfold increase in titer over a 1-year period. There were 40 total seroconversions to at least one pathogen, including R. parkeri (n = 19), "R. amblyommii" (n = 14), R. rickettsii (n = 9), and E. chaffeensis (n = 8). There were no subjects whose sera were reactive to B. burgdorferi C6 antigen. Thirty-eight of the 40 incident infections were subclinical. The overall risk of infection by any pathogen during the study period was 0.26, and the risk among the NC Division of Forest Resources workers was 1.73 times that of workers in other divisions (95% confidence interval [CI]: 1.02, 2.92). The risk of infection was lower in subjects wearing permethrin-impregnated clothing, but not significantly (risk ratio = 0.81; 95% CI: 0.47, 1.39). In summary, outdoor workers in North Carolina are at high risk of incident tick-borne infections, most of which appear to be asymptomatic. |
Development and Validation of an Improved PCR Method Using the 23S-5S Intergenic Spacer for Detection of Rickettsiae in Dermacentor variabilis Ticks and Tissue Samples from Humans and Laboratory Animals.
Kakumanu ML , Ponnusamy L , Sutton HT , Meshnick SR , Nicholson WL , Apperson CS . J Clin Microbiol 2016 54 (4) 972-9 A novel nested PCR assay was developed to detect Rickettsia spp. in ticks and tissue samples from humans and laboratory animals. Primers were designed for the nested run to amplify a variable region of the 23S-5S intergenic spacer of Rickettsia spp. The newly designed primers were evaluated using genomic DNA from 11 Rickettsia species, belonging to the spotted fever, typhus, and ancestral groups and in parallel compared to other Rickettsia-specific PCR targets (ompA, gltA and 17-kDa). The new 23S-5S nested PCR assay amplified all 11 Rickettsia spp. but the assays employing other PCR targets did not. The novel nested assay was sensitive enough to detect one copy of a cloned 23S-5S IGS fragment from "Candidatus R. amblyommii". Subsequently, the detection efficiency of the 23S-5S nested assay was compared to the other three assays using genomic DNA extracted from 40 adult Dermacentor variabilis ticks. The nested 23S-5S assay detected Rickettsia DNA in 45% of the ticks while the amplification rate of the three other assays ranged between 5-20%. The novel PCR assay was validated using clinical samples from humans and laboratory animals that were known to be infected with pathogenic species of Rickettsia. The nested 23S-5S PCR assay was coupled with reverse line blot hybridization with species-specific probes for high-throughput detection and simultaneous identification of the species of Rickettsia in the ticks. Rickettsia amblyommii, R. montanensis, R. felis and R. bellii were frequently identified species along with some potentially novel Rickettsia that were closely related to R. bellii and R. conorii. |
Human infection with Ehrlichia muris-like pathogen, United States, 2007-2013
Johnson DK , Schiffman EK , Davis JP , Neitzel DF , Sloan LM , Nicholson WL , Fritsche TR , Steward CR , Ray JA , Miller TK , Feist MA , Uphoff TS , Franson JJ , Livermore AL , Deedon AK , Theel ES , Pritt BS . Emerg Infect Dis 2015 21 (10) 1794-9 An Ehrlichia muris-like (EML) pathogen was detected among 4 patients in Minnesota and Wisconsin during 2009. We characterized additional cases clinically and epidemiologically. During 2004-2013, blood samples from 75,077 patients from all 50 United States were tested by PCR from the groEL gene for Ehrlichia spp. and Anaplasma phagocytophilum. During 2007-2013, samples from 69 (0.1%) patients were positive for the EML pathogen; patients were from 5 states: Indiana (1), Michigan (1), Minnesota (33), North Dakota (3), and Wisconsin (31). Most (64%) patients were male; median age was 63 (range 15-94) years; and all 69 patients reported likely tick exposure in Minnesota or Wisconsin. Fever, malaise, thrombocytopenia, and lymphopenia were the most common symptoms. Sixteen (23%) patients were hospitalized (median 4 days); all recovered, and 96% received doxycycline. Infection with the EML pathogen should be considered for persons reporting tick exposure in Minnesota or Wisconsin. |
Serological investigation of heartland virus (Bunyaviridae: Phlebovirus) exposure in wild and domestic animals adjacent to human case sites in Missouri 2012-2013
Bosco-Lauth AM , Panella NA , Root JJ , Gidlewski T , Lash RR , Harmon JR , Burkhalter KL , Godsey MS , Savage HM , Nicholson WL , Komar N , Brault AC . Am J Trop Med Hyg 2015 92 (6) 1163-7 Heartland virus (HRTV; Bunyaviridae, Phlebovirus) has recently emerged as the causative agent of human disease characterized by thrombocytopenia and leukopenia in the United States. The lone star tick (Amblyomma americanum L.) has been implicated as a vector. To identify candidate vertebrate amplification hosts associated with enzootic maintenance of the virus, sera and ticks were sampled from 160 mammals (8 species) and 139 birds (26 species) captured near two human case residences in Andrew and Nodaway Counties in northwest Missouri. HRTV-specific neutralizing antibodies were identified in northern raccoons (42.6%), horses (17.4%), white-tailed deer (14.3%), dogs (7.7%), and Virginia opossums (3.8%), but not in birds. Virus isolation attempts from sera and ticks failed to detect HRTV virus. The high antibody prevalence coupled with local abundance of white-tailed deer and raccoons indicates these species as candidate amplification hosts. |
Bartonella spp. bacteremia in blood donors from Campinas, Brazil.
Pitassi LH , de Paiva Diniz PP , Scorpio DG , Drummond MR , Lania BG , Barjas-Castro ML , Gilioli R , Colombo S , Sowy S , Breitschwerdt EB , Nicholson WL , Velho PE . PLoS Negl Trop Dis 2015 9 (1) e0003467 Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%). Sixteen donors (3.2%) were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions. |
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