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Silva-Ramos CR, Faccini-Martínez ÁA. Clinical, epidemiological, and laboratory features of Rickettsia africae infection, African tick-bite fever: A systematic review. LE INFEZIONI IN MEDICINA 2022; 29:366-377. [PMID: 35146341 DOI: 10.53854/liim-2903-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/27/2021] [Indexed: 11/03/2022]
Abstract
African tick-bite fever (ATBF), caused by Rickettsia africae, is the main tick-borne rickettsiosis and the second most frequent cause of fever after malaria in travelers returning from sub-Saharan Africa. General descriptions on ATBF were made in the first two decades after recognized as a new infectious entity, and since then, many authors have contributed to the knowledge of the disease by reporting clinical cases in scientific literature. We developed a systematic review that evaluated all available evidence in the literature regarding clinical, epidemiological, and laboratory features of confirmed R. africae rickettsiosis cases. We followed the recommendations made by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guide. A total of 48 scientific publications (108 confirmed cases) were analyzed in order to extract data for developing this review. Overall, our results show that R. africae rickettsiosis is more frequent in males in the age group of 18-64 years, more than 80% of the cases occurred in European travelers, South Africa was the country where most infections were acquired, and almost 40% of cases occurred in clusters. Clinically, more than 80% of the cases had fever and eschar (55% developed multiple eschars), rash was present in less than the half of cases, and lymphangitis was not a common sign (11%). Headache, myalgia and regional lymphadenopathy were predominant nonspecific clinical manifestation (mean of 60%, 49% and 51%, respectively). Our results show that at least 70% of R. africae cases had altered laboratory parameters, most often showing an increase in transaminases and C-reactive protein. Tetracycline-class antibiotics, as monotherapy, were used in most (>90%) of the patients. Overall, only 4% of cases had complications, 12% required hospitalization, and there was a 100% rate of clinical recovery.
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Affiliation(s)
- Carlos Ramiro Silva-Ramos
- Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Álvaro A Faccini-Martínez
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Committee of Tropical Medicine, Zoonoses and Travel Medicine, Asociación Colombiana de Infectología, Bogotá, Colombia
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Essbauer S, Hofmann M, Kleinemeier C, Wölfel S, Matthee S. Rickettsia diversity in southern Africa: A small mammal perspective. Ticks Tick Borne Dis 2017; 9:288-301. [PMID: 29174365 DOI: 10.1016/j.ttbdis.2017.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 11/01/2017] [Accepted: 11/09/2017] [Indexed: 10/18/2022]
Abstract
Worldwide, including Africa, rickettsioses are recognized as emerging or re-emerging infections. To date, little is known about the diversity of Rickettsia species that are naturally associated with small mammals in southern Africa. The aim of the study was to screen a diversity of small mammals for the presence of rickettsial DNA. Animals were trapped at 38 localities in South Africa and Namibia. In total, 1616 ear-tissue samples from 23 species representing 17 genera were tested using real-time (rt)PCR and multi-locus sequence typing (MLST). Of the 1616 samples 251 (15.5%) were positive in an initial rtPCR. In 16 of the 23 investigated animal species rickettsial DNA was detected with an average prevalence of 15.7%. We herein describe for the first time four Rickettsia (R.) species known to be pathogenic for humans in rodents from South Africa, R. conorii, R. massiliae, R. felis and R. helvetica. In addition, by MLST and subsequent phylogenetic analyses so far undescribed Rickettsia species, Candidatus Rickettsia africaustralis, Candidatus Rickettsia rhabdomydis, and Candidatus Rickettsia muridii were confirmed. Further four new genotypes, genotype Rickettsia hofmannii, genotype Rickettsia stutterheimensis, genotype Rickettsia hogsbackensis and genotype Rickettsia kaalplaasensis, respectively, are described. The data indicate a surprisingly high diversity of Rickettsia in small mammals in South Africa and might indicate their possible role as reservoirs for Rickettsia. Ecological questions concerning their natural hosts such as small mammals, but also the role of livestock or pet animals, require further investigation. Particularly, data on the relevance of these rickettsiae for diseases in humans are of further interest.
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Affiliation(s)
- Sandra Essbauer
- Bundeswehr Institute of Microbiology, Department Virology and Rickettsiology, Neuherbergstr. 11, 80937 Muenchen, Germany.
| | - Mirja Hofmann
- Bundeswehr Institute of Microbiology, Department Virology and Rickettsiology, Neuherbergstr. 11, 80937 Muenchen, Germany
| | - Christoph Kleinemeier
- Bundeswehr Institute of Microbiology, Department Virology and Rickettsiology, Neuherbergstr. 11, 80937 Muenchen, Germany
| | - Silke Wölfel
- Bundeswehr Institute of Microbiology, Department Virology and Rickettsiology, Neuherbergstr. 11, 80937 Muenchen, Germany
| | - Sonja Matthee
- Department of Conservation Ecology and Entomology, Stellenbosch University, Matieland, South Africa
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Ndip LM, Biswas HH, Nfonsam LE, LeBreton M, Ndip RN, Bissong MA, Mpoudi-Ngole E, Djoko C, Tamoufe U, Prosser AT, Burke DS, Wolfe ND. Risk factors for African tick-bite fever in rural central Africa. Am J Trop Med Hyg 2011; 84:608-13. [PMID: 21460018 PMCID: PMC3062457 DOI: 10.4269/ajtmh.2011.10-0191] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
African tick-bite fever is an emerging infectious disease caused by the spotted fever group Rickettsia, Rickettsia africae, and is transmitted by ticks of the genus Amblyomma. To determine the seroprevalence of exposure to R. africae and risk factors associated with infection, we conducted a cross-sectional study of persons in seven rural villages in distinct ecological habitats of Cameroon. We examined 903 plasma samples by using an indirect immunofluorescence assay for antibodies to R. africae and analyzed demographic and occupational data collected from questionnaires. Of the 903 persons tested, 243 (26.9%) had IgG/IgM/IgA reactive with R. africae. Persons from four of the seven village sites were significantly more likely to be seropositive (P < 0.05), and lowland forest sites tended to have higher seroprevalences. These results suggest that African tick-bite fever is common in adults in rural areas of Cameroon and that ecological factors may play a role in the acquisition of R. africae infection.
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Affiliation(s)
- Lucy M Ndip
- Department of Biochemistry and Microbiology, University of Buea, Buea, Cameroon
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Svendsen CB, Milman N, Nielsen HW, Krogfelt KA, Larsen KR. A prospective study evaluating the presence of Rickettsia in Danish patients with sarcoidosis. ACTA ACUST UNITED AC 2010; 41:745-52. [PMID: 19685374 DOI: 10.1080/00365540903177727] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Rickettsia helvetica has previously been proposed as an aetiological agent in sarcoidosis. The purpose of the present study was to detect possible signs of Rickettsia infection in a Danish population of patients with sarcoidosis. Twenty-six patients with newly diagnosed sarcoidosis were prospectively enrolled in the study. The diagnosis was confirmed by biopsy in 18 and by clinical characteristics in 8 patients; 11 patients with different non-sarcoid lung diseases were recruited as controls. We obtained information regarding tick exposure and sarcoid disease manifestations by a structured interview. Evidence of rickettsial infection was assessed by an immunofluorescence assay testing for antibodies towards Rickettsia as well as specific real-time polymerase chain reaction (PCR) on lung biopsy specimens. We performed fluorescent in situ hybridization (FISH) on the biopsies to detect rickettsial and eubacterial rRNA. One sarcoidosis patient had serum rickettsial IgG antibodies above the chosen cut-off level. We found no positive rickettsial PCR or FISH analyses in any of the biopsy specimens. One sarcoid patient sample and 1 control sample contained unidentified bacteria. There was no difference in the reported frequency of tick bite between patients and controls. In conclusion, we found no evidence of Rickettsia being involved in the pathogenesis of sarcoidosis in Denmark.
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Affiliation(s)
- Claus Bo Svendsen
- Department of Bacteriology, Mycology and Parasitology, Statens Serum Institute, Copenhagen, Denmark.
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Lepidi H, Fournier PE, Raoult D. Histologic features and immunodetection of African tick-bite fever eschar. Emerg Infect Dis 2006; 12:1332-7. [PMID: 17073080 PMCID: PMC3294730 DOI: 10.3201/eid1209.051540] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Immunohistochemical detection of rickettsial antigens may be useful in diagnosis. African tick-bite fever (ATBF) is a rickettsiosis caused by Rickettsia africae. We describe histologic features and immunodetection of R. africae in cutaneous inoculation eschars from 8 patients with ATBF, which was diagnosed by culture or association of positive PCR detection and positive serologic results. We used quantitative image analysis to compare the pattern of inflammation of these eschars with those from Mediterranean spotted fever. We evaluated the diagnostic value of immunohistochemical techniques by using a monoclonal antibody to R. africae. ATBF eschars were histologically characterized by inflammation of vessels composed mainly of significantly more polymorphonuclear leukocytes than are found in cases of Mediterranean spotted fever (p<0.05). Small amounts R. africae antigens were demonstrated by immunohistochemical examination in 6 of 8 patients with ATBF. Neutrophils in ATBF are a notable component of the host reaction, perhaps because ATBF is a milder disease than the other rickettsioses. Immunohistochemical detection of rickettsial antigens may be useful in diagnosing ATBF.
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Abstract
In Europe, rickettsioses are long-known infectious diseases. Until recently, it was thought that Mediterranean spotted fever due to Rickettsia conorii was the only tick-borne rickettsiosis in Europe. In the last decade new Rickettsia spp. have been implicated in human pathology (R. slovaca, R. sibirica mongolotimonae, R. helvetica). Furthermore, cases of infection due to flea-borne rickettsioses (R. typhi, R. felis) have been described. Finally, although no outbreak of epidemic typhus has been reported yet in central and southern Europe, we should be aware of the possibility of reemergence of this disease in Europe. Other rickettsioses exist that have not yet been implicated in human pathology. We should consider that climate changes and other factors could contribute to the emergence and reemergence of other new diseases.
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Affiliation(s)
- J R Blanco
- Area de Enfermedades Infecciosas, Complejo San Millán-San Pedro-de La Rioja, Hospital de La Rioja, Avd. Viana 1, 26001, Logroño (La Rioja), Spain.
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Oteo JA, Portillo A, Blanco JR, Ibarra V, Santibáñez S. [Rickettsia africae infection. Three cases confirmed by PCR]. Med Clin (Barc) 2004; 122:786-8. [PMID: 15207109 DOI: 10.1016/s0025-7753(04)74386-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE African tick bite fever or Rickettsia africae infection has been recognized as an emerging health problem in the last few years. The aim of this study was to describe 3 cases of Spanish tourists who suffered from R. africae infection after visiting South Africa. PATIENTS AND METHOD Three patients with a suspected rickettsial disease according to epidemiological and clinical manifestations (fever, eschar and exanthema) were studied. Antibodies against Rickettsia conorii were determined by IFI assays. Semi-nested PCR reactions (rOmpA) and subsequent sequence analysis of the amplified products were also carried out. RESULTS Epidemiological and clinical aspects of this rickettsiosis are described. For diagnosis of this rickettsial disease, conventional serological assays (IFI) were less useful than semi-nested rOmpA PCR reactions, which showed a sensitivity of 100% in our samples. CONCLUSIONS Three cases of R. africae infection are reported. PCR and subsequent sequencing of the amplicons are useful for the microbiological confirmation of this type of infection. We must think about African tick-bite fever as a possible diagnosis in patients with a febrile rash after returning from endemic areas.
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Affiliation(s)
- José A Oteo
- Servicio de Medicina Interna y Enfermedades Infecciosas, Hospital de La Rioja, Logroño, España.
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Jackson Y, Chappuis F, Loutan L. African tick-bite fever: four cases among Swiss travelers returning from South Africa. J Travel Med 2004; 11:225-8. [PMID: 15541225 DOI: 10.2310/7060.2004.19006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND African tick-bite fever (ATBF) is a recently described disease belonging to the spotted fever group. It is caused by Rickettsia africae, and cases are mainly diagnosed in travelers returning from sub-Saharan Africa. METHODS We report four cases of ATBF among Swiss travelers returning from a 1-month trip in rural South Africa. Diagnosis was made on the basis of clinical, epidemiologic and serologic findings that we describe in detail. Serology was performed using microimmunofluorescence (MIF) assay 2 weeks, 6 weeks and 14 months after the commencement of symptoms. RESULTS All patients developed the typical eschar and a rash; two had a local lymphadenopathy and one a lymphangitic reaction. Two patients developed transient neuropsychiatric symptoms such as headache, irritability and depressed mood. All four patients had rises in both IgM and IgG classes of anti-R. africae antibodies. After 1 year, only two patients still had measurable circulating antibodies. Cross-reactions with R. conorii were noted. Three patients were cured after a short course of doxycycline; one required 15 days of treatment. CONCLUSIONS ATBF is a benign disease increasingly being diagnosed in travelers. After ruling out malaria, ATBF diagnosis relies upon a detailed travel history and the classical findings of influenza-like symptoms, fever, one or more necrotic eschars, and rash. Serologic tests usually help to confirm the diagnosis. Neuropsychiatric symptoms specifically associated with ATBF are reported here for the first time.
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Affiliation(s)
- Yves Jackson
- Unit of Travel and Migration Medicine, Department of Community Medicine, University Hospital Geneva, Geneva, Switzerland
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Ndip LM, Bouyer DH, Da Rosa APT, Titanji V, Tesh RB, Walker DH. Acute spotted fever rickettsiosis among febrile patients, Cameroon. Emerg Infect Dis 2004; 10:432-7. [PMID: 15109409 PMCID: PMC3322773 DOI: 10.3201/eid1003.020713] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although potential arthropod vectors are abundant in Cameroon, acute febrile illnesses are rarely evaluated for arboviral or rickettsial infections. Serum samples from 234 acutely febrile patients at clinics in Tiko and Buea, Cameroon, were examined for antibodies to Rickettsia africae and African alphaviruses and flaviviruses. These serum samples did not contain antibodies against typhoid, and blood malarial parasites were not detected. Serum samples of 32% contained immunoglobulin M antibodies reactive with R. africae by immunofluorescence assay and were reactive with outer membrane proteins A and B of R. africae by immunoblotting. These findings established a diagnosis of acute rickettsiosis, most likely African tick-bite fever. Hemagglutination inhibition testing of the serum samples also detected antibodies to Chikungunya virus (47%) and flaviviruses (47%). High prevalence of antibodies to arboviruses may represent a major, previously unrecognized public health problem in an area where endemic malaria and typhoid fever have been the principal diagnostic considerations.
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Affiliation(s)
- Lucy M. Ndip
- University of Buea, Buea, South West Province, Cameroon
| | | | | | | | - Robert B. Tesh
- University of Texas Medical Branch, Galveston, Texas, USA
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Jensenius M, Fournier PE, Raoult D. Tick-borne rickettsioses in international travellers. Int J Infect Dis 2004; 8:139-46. [PMID: 15109588 DOI: 10.1016/j.ijid.2003.06.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2003] [Revised: 06/24/2003] [Accepted: 06/25/2003] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Tick-borne rickettsioses are of emerging importance in today's travel medicine but have until recently received little attention. We describe the current knowledge of tick-borne rickettsioses as they relate to international travel, their microbiological diagnosis, treatment, possible prevention, and future prospects. METHODS Literature-based review and personal observations. RESULTS During the last decade, some 400 cases of tick-borne rickettsioses have been reported in international travellers, the vast majority being African tick bite fever caused by Rickettsia africae and Mediterranean spotted fever caused by Rickettsia conorii. Only a minority of infected travellers can recall a preceding tick bite. Most patients present with a mild-to-moderately severe flu-like illness typically accompanied by a cutaneous rash and an inoculation eschar at the site of the tick bite, but potentially life-threatening disease with disseminated vaculitis is occasionally seen. Definite microbiological confirmation of tick-borne rickettsioses by isolation or antigen detection is only available at reference laboratories and diagnosis must in most cases rely on clinical and epidemiological data supported by serology. Doxycycline is the recommended treatment for tick-borne rickettsioses and prevention is based on personal protective measures against tick bites when travelling in endemic areas. CONCLUSION Tick-borne rickettsiosis should be suspected in febrile returnees from endemic areas, especially in cases with skin eruptions. Travellers to endemic areas should be encouraged to use personal protective measures against tick bites.
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Affiliation(s)
- Mogens Jensenius
- Department of Internal Medicine, Aker University Hospital, Oslo, Norway.
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Ndip LM, Bouyer DH, Travassos Da Rosa APA, Titanji VPK, Tesh RB, Walker DH. Acute spotted fever rickettsiosis among febrile patients, Cameroon. Emerg Infect Dis 2004. [PMID: 15109409 DOI: 10.32012/eid1003.020713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Although potential arthropod vectors are abundant in Cameroon, acute febrile illnesses are rarely evaluated for arboviral or rickettsial infections. Serum samples from 234 acutely febrile patients at clinics in Tiko and Buea, Cameroon, were examined for antibodies to Rickettsia africae and African alphaviruses and flaviviruses. These serum samples did not contain antibodies against typhoid, and blood malarial parasites were not detected. Serum samples of 32% contained immunoglobulin M antibodies reactive with R. africae by immunofluorescence assay and were reactive with outer membrane proteins A and B of R. africae by immunoblotting. These findings established a diagnosis of acute rickettsiosis, most likely African tick-bite fever. Hemagglutination inhibition testing of the serum samples also detected antibodies to Chikungunya virus (47%) and flaviviruses (47%). High prevalence of antibodies to arboviruses may represent a major, previously unrecognized public health problem in an area where endemic malaria and typhoid fever have been the principal diagnostic considerations.
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Affiliation(s)
- Lucy M Ndip
- University of Buea, Buea, South West Province, Cameroon
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Jensenius M, Fournier PE, Hellum KB, Wesslén L, Caruso G, Priø T, Løhne K, Vene S, Raoult D, Myrvang B. Sequential changes in hematologic and biochemical parameters in African tick bite fever. Clin Microbiol Infect 2003; 9:678-83. [PMID: 12925109 DOI: 10.1046/j.1469-0691.2003.00713.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the sequential changes and to estimate the frequencies of abnormalities in some commonly measured biological variables in patients with African tick bite fever (ATBF), an emerging spotted fever group (SFG) rickettsiosis in international travelers to rural sub-Saharan Africa. METHODS A study was done of hemoglobin, total leukocyte count, absolute lymphocyte count, blood platelet count and serum levels of C-reactive protein (S-CRP), alanine aminotransferase (S-ALAT), aspartate aminotransferase, lactic dehydrogenase, gamma-glutamyl transferase, alkaline phosphatase, bilirubin, sodium and creatinine during the first two weeks of illness and prior to the institution of antirickettsial therapy in 108 patients with travel-associated ATBF. RESULTS There were significant falls in mean total leukocyte count, mean absolute lymphocyte count, and mean platelet count, and significant increases in mean S-CRP and S-ALAT. During the first ten days of illness, elevated S-CRP, lymphopenia and elevated S-ALAT were detected in 91.7%, 73.3% and 40.7% of patients, respectively. Most abnormalities were mild. For 55 patients who underwent both S-CRP and absolute lymphocyte count determination, at least one parameter was abnormal in 52 (94.5%) patients. CONCLUSIONS The sequential changes in many biological parameters during the acute phase of ATBF mimic those reported in other SFG rickettsioses. Mild abnormalities are frequent, with increased S-CRP and lymphopenia being the two most consistent findings.
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Affiliation(s)
- M Jensenius
- Department of Internal Medicine, Department of Clinical Chemistry, Aker University Hospital, Oslo, Norway.
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Jensenius M, Fournier PE, Vene S, Hoel T, Hasle G, Henriksen AZ, Hellum KB, Raoult D, Myrvang B. African tick bite fever in travelers to rural sub-Equatorial Africa. Clin Infect Dis 2003; 36:1411-7. [PMID: 12766836 DOI: 10.1086/375083] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Accepted: 02/06/2003] [Indexed: 11/03/2022] Open
Abstract
To estimate the incidence of, identify risk factors for, and describe the clinical presentation of travel-associated African tick bite fever (ATBF), a rapidly emerging disease in travel medicine, we prospectively studied a cohort of 940 travelers to rural sub-Equatorial Africa. Diagnosis was based on suicide polymerase chain reaction and the detection of specific antibodies to Rickettia africae in serum samples by multiple-antigen microimmunofluorescence assay, Western blotting, and cross-adsorption assays. Thirty-eight travelers, 4.0% of the cohort and 26.6% of those reporting flulike symptoms, had ATBF diagnosed. More than 80% of the patients had fever, headache, and/or myalgia, whereas specific clinical features such as inoculation eschars, lymphadenitis, cutaneous rash, and aphthous stomatitis were seen in < or = 50% of patients. Game hunting, travel to southern Africa, and travel during November through April were found to be independent risk factors. Our study suggests that ATBF is not uncommon in travelers to rural sub-Saharan Africa and that many cases have a nonspecific presentation.
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Affiliation(s)
- Mogens Jensenius
- Department of Internal Medicine, Aker University Hospital, Oslo, Norway.
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14
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Pretorius AM, Jensenius M, Clarke F, Ringertz SH. Repellent efficacy of DEET and KBR 3023 against Amblyomma hebraeum (Acari: Ixodidae). JOURNAL OF MEDICAL ENTOMOLOGY 2003; 40:245-248. [PMID: 12693855 DOI: 10.1603/0022-2585-40.2.245] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The bont tick, Amblyomma hebraeum Koch, is the principal vector of Rickettsia africae, the agent of African tick bite fever, in southern Africa. In contrast to most other hard ticks, members of the genus Amblyomma exhibit a characteristic attack host-seeking behavior. The efficacy of topically applied 20% lotions of DEET (diethyl-3-methylbenzamide), the currently considered reference repellent substance, and KBR 3023, a recently developed piperidine compound, was evaluated against laboratory-reared A. hebraeum nymphs on treated fingers. Both substances repelled >85% of nymph attacks at 0 and 1 h postapplication. At 2, 3, and 4 h, the repellent efficacies of DEET were 84%, 68% and 71%, whereas those of KBR 3023 were 56, 55, and 54%. The observed differences between the two test substances were statistically significant only at 2 h postapplication. This first study of topical repellents against A. hebraeum suggests that 20% lotions of DEET and KBR 3023 are effective for 2 and 1 h, respectively, but that the repellent efficacies decrease thereafter.
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Affiliation(s)
- Anne-Marié Pretorius
- Department of Medical Microbiology, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa.
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Bottieau E, Clerinx J, Colebunders R, Van Gompel A. Fever after a stay in the tropics. Part 2: Common imported tropical diseases. Acta Clin Belg 2002; 57:301-8. [PMID: 12723247 DOI: 10.1179/acb.2002.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- E Bottieau
- Instituut voor Tropische Geneeskunde, Departement Klinische Wetenschappen, Nationalestraat 155, 2000 Antwerpen, België.
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Durrheim DN, Braack L, Grobler D, Bryden H, Speare R, Leggat PA. Safety of travel in South Africa: the Kruger National Park. J Travel Med 2001; 8:176-91. [PMID: 11703901 DOI: 10.2310/7060.2001.24239] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- D N Durrheim
- Communicable Disease Control, Mpumalanga Department of Health, South Africa
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Raoult D, Fournier PE, Fenollar F, Jensenius M, Prioe T, de Pina JJ, Caruso G, Jones N, Laferl H, Rosenblatt JE, Marrie TJ. Rickettsia africae, a tick-borne pathogen in travelers to sub-Saharan Africa. N Engl J Med 2001; 344:1504-10. [PMID: 11357153 DOI: 10.1056/nejm200105173442003] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND African tick-bite fever occurs after contact with ticks that carry Rickettsia africae and that parasitize cattle and game. Sporadic reports suggest that this infection has specific clinical and epidemiologic features. METHODS We studied patients who were tested for a rickettsial disease after returning from a visit to Africa or Guadeloupe. To assess the value of the microimmunofluorescence assay, Western blotting, and cross-adsorption assays, we compared the results of these tests in 39 patients in whom African tick-bite fever had been confirmed by the polymerase-chain reaction assay, cell culture, or both; 50 patients with documented R. conorii infection; and 50 blood donors. These diagnostic criteria were then applied to 376 additional patients who had returned from southern Africa and 2 who had returned from Guadeloupe and whose serum was being tested for rickettsial disease. RESULTS In the 39 patients with direct evidence of R. africae infection, the combination of microimmunofluorescence assay, Western blotting, and cross-adsorption assays showing antibodies specific for R. africae had a sensitivity of 0.56; however, each test had a positive predictive value and a specificity of 1.0. An additional 80 patients were found to have an R. africae infection on the basis of these serologic criteria. Infections with R. africae were acquired by visitors to 11 African countries and Guadeloupe. The illness was generally mild and was characterized by a rash in 46 percent of the patients; the rash was usually maculopapular or vesicular and rarely purpuric. Ninety-five percent of patients had an inoculation eschar or eschars, and 54 percent of these patients had multiple eschars, a finding that is unusual in patients with rickettsial infection. CONCLUSIONS In this series, R. africae was the cause of nearly all cases of tick-bite rickettsiosis in patients who became ill after a trip to sub-Saharan Africa.
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Affiliation(s)
- D Raoult
- Unité des Rickettsies, Faculté de Médecine, Université de la Méditerranée, Marseilles, France.
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Ki-Zerbo G, Tall F, Nagalo K, Ledru E, Durand G, Patey O. Séroprévalence des rickettsioses et de la fièvre Q chez les patients fébriles à l'hôpital de Bobo-Dioulasso (Burkina Faso). Med Mal Infect 2000. [DOI: 10.1016/s0399-077x(00)89140-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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