Relapsing fever - a forgotten disease revealed

Cutler, Sally J.

doi:10.1111/j.1365-2672.2009.04598.x

Cited by 127 publications

(112 citation statements)

References 42 publications

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“…7 and 8). All infected organ types produced greater infectious virus replication than the initial inoculum control (with no organs) at multiple time points 4 LGTV GFP replication in infected synganglion culture. Magnification, ϫ10 (organ with GFP filter imaging).…”

Section: Resultsmentioning

confidence: 99%

Flavivirus Infection ofIxodes scapularis(Black-Legged Tick)Ex VivoOrganotypic Cultures and Applications for Disease Control

Grabowski¹,

Tsetsarkin

Long³

et al. 2017

mBio

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Ixodes scapularis ticks transmit many infectious agents that cause disease, including tick-borne flaviviruses (TBFVs). TBFV infections cause thousands of human encephalitis cases worldwide annually. In the United States, human TBFV infections with Powassan virus (POWV) are increasing and have a fatality rate of 10 to 30%. Additionally, Langat virus (LGTV) is a TBFV of low neurovirulence and is used as a model TBFV. TBFV replication and dissemination within I. scapularis organs are poorly characterized, and a deeper understanding of virus biology in this vector may inform effective countermeasures to reduce TBFV transmission. Here, we describe short-term, I. scapularis organ culture models of TBFV infection. Ex vivo organs were metabolically active for 9 to 10 days and were permissive to LGTV and POWV replication. Imaging and videography demonstrated replication and spread of green fluorescent protein-expressing LGTV in the organs. Immunohistochemical staining confirmed LGTV envelope and POWV protein synthesis within the infected organs.LGTV-and POWV-infected organs produced infectious LGTV and POWV; thus, the ex vivo cultures were suitable for study of virus replication in individual organs. LGTVand POWV-infected midgut and salivary glands were subjected to double-stranded RNA (dsRNA) transfection with dsRNA to the LGTV 3= untranslated region (UTR), which reduced infectious LGTV and POWV replication, providing a proof-of-concept use of RNA interference in I. scapularis organ cultures to study the effects on TBFV replication. The results contribute important information on TBFV localization within ex vivo I. scapularis organs and provide a significant translational tool for evaluating recombinant, live vaccine candidates and potential tick transcripts and proteins for possible therapeutic use and vaccine development to reduce TBFV transmission.IMPORTANCE Tick-borne flavivirus (TBFV) infections cause neurological and/or hemorrhagic disease in humans worldwide. There are currently no licensed therapeutics or vaccines against Powassan virus (POWV), the only TBFV known to circulate in North America. Evaluating tick vector targets for antitick vaccines directed at reducing TBFV infection within the arthropod vector is a critical step in identifying efficient approaches to controlling TBFV transmission. This study characterized infection of female Ixodes scapularis tick organ cultures of midgut, salivary glands, and synganglion with the low-neurovirulence Langat virus (LGTV) and the more pathogenic POWV. Cell types of specific organs were susceptible to TBFV infection, and a difference in LGTV and POWV replication was noted in TBFV-infected organs. This tick organ culture model of TBFV infection will be useful for various applications,

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Section: Resultsmentioning

confidence: 99%

Flavivirus Infection ofIxodes scapularis(Black-Legged Tick)Ex VivoOrganotypic Cultures and Applications for Disease Control

Grabowski¹,

Tsetsarkin

Long³

et al. 2017

mBio

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“…African TBRF is associated with proximity to tick-infested burrows and huts [8,9]. In contrast, LBRF is caused by B. recurrentis, which is transmitted by body louse (P. humanus corporis).…”

Section: Introductionmentioning

confidence: 99%

Knowledge, Attitude and Practices of High Risk Populations on Louse- Borne Relapsing Fever in Bahir Dar City, North-West Ethiopia

Yimer¹

2014

SJPH

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Background: Louse-borne relapsing fever (LBRF) is an acute febrile illness caused by Borrelia recurrentis (B. recurrentis). It is transmitted by body lice, Pediculus humanus corporis (P. humanus corporis). LBRF is more prevalent in high risk populations such as prisoners, street children and yekolotemaries (traditional students of the Ethiopian Orthodox Church with low levels of socio economic status and poor personal hygiene). Thus, this study was conducted to assess the knowledge, attitude and practices (KAPs) among high risk populations towards LBRF prevention in Bahir Dar city. Methods: A cross-sectional survey was conducted on KAPs of high risk populations regarding LBRF from November to December, 2012. Data was collected using a standardized pre-tested closed ended questionnaire by face to face interviews to address socio demographic characteristics, KAPs and sources of information regarding LBRF prevention. The overall KAPs of the study participants were analyzed using the sum score of each outcome based on Bloom's cut-off point (60-80%). Having a score above the cut-off point was equated with having high levels of knowledge, positive attitude and good practice. Results: Of the 407 study participants, 383 (94.1%) were males with the mean age of 31 years. Among the study participants, 243 (59.7%) had no formal education. The response rate of the participants was 98.2%. Overall, 222 (54.5%) of the study participants had low knowledge, 247(60.7%) had neutral attitude (30-39 scores out of 50 item-questions on LBRF) and 320 (78.6%) had fair practice (20-25 scores out of 32 item-questions). Prisoners had the highest knowledge, attitude and practices followed by street children and yekolotemaries towards LBRF prevention (p < 0.001). Conclusion: The overall KAPs of the high risk populations towards prevention of LBRF were poor. However, prisoners had highest level followed by street children and yekolotemaries. Moreover, the sources of information on LBRF received by the high risk populations have determined their KAP levels towards LBRF prevention. This showed that information on LBRF using television, radio and through their friends is essential to bring knowledge and attitudinal change towards LBRF prevention.

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“…12 The body louse is the main vector of three pathogenic bacteria: Bartonella quintana, the agent of trench fever; Borrelia recurrentis, the agent of louse-borne relapsing fever; and Rickettsia prowazekii, the agent of epidemic typhus. 13,14 B. quintana is a Gram-negative bacterium that causes trench fever, bacillary angiomatosis, endocarditis, chronic bacteremia, and chronic lymphadenopathy. 15 It has typically been transmitted by body lice, but recently, DNA of B. quintana has also been found in head lice collected from homeless individuals in Nepal, 9 the United States, 16 France, 17 Senegal, 11 and Ethiopia.…”

Section: Introductionmentioning

confidence: 99%

Detection of Bartonella quintana in African Body and Head Lice

Sangaré¹,

Boutellis²,

Drali³

et al. 2014

The American Society of Tropical Medicine and Hygiene

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Abstract. Currently, the body louse is the only recognized vector of Bartonella quintana, an organism that causes trench fever. In this work, we investigated the prevalence of this bacterium in human lice in different African countries. We tested 616 head lice and 424 body lice from nine African countries using real-time polymerase chain reaction targeting intergenic spacer region 2 and specific B. quintana genes. Overall, B. quintana DNA was found in 54% and 2% of body and head lice, respectively. Our results also show that there are more body lice positive for B. quintana in poor countries, which was determined by the gross domestic product, than in wealthy areas (228/403 versus 0/21, P 0.001). A similar finding was obtained for head lice (8/226 versus 2/390, P = 0.007). Our findings suggest that head lice in Africa may be infected by B. quintana when patients live in poor economic conditions and are also exposed to body lice.

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Relapsing fever - a forgotten disease revealed

Cited by 127 publications

References 42 publications

Flavivirus Infection ofIxodes scapularis(Black-Legged Tick)Ex VivoOrganotypic Cultures and Applications for Disease Control

Flavivirus Infection ofIxodes scapularis(Black-Legged Tick)Ex VivoOrganotypic Cultures and Applications for Disease Control

Knowledge, Attitude and Practices of High Risk Populations on Louse- Borne Relapsing Fever in Bahir Dar City, North-West Ethiopia

Detection of Bartonella quintana in African Body and Head Lice

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