First report of African tick-bite fever in a South American traveler

Abstract

We report a clinical case of African tick-bite fever in a Brazilian traveler right after his return from South Africa. Definitive diagnosis was supported by seroconversion between acute-phase and convalescent-phase serum samples, detection of rickettsial DNA in skin lesions, and in vitro culture of Rickettsia africae from the patient’s skin. Most of the previous reported cases of African tick-bite fever were confirmed solely by serological or/and molecular methods. Through this first confirmed case of African tick-bite fever in Brazil, it is quite possible that other cases are occurring unnoticed by the health authorities, requiring a greater vigilance in traveler’s medicine in South America.

Rickettsia africae an Agent of African Tick Bite Fever in Ticks Collected from Domestic Animals in Eastern Cape, South Africa

“…Lorusso et al [30] were the first people to report about R. africae in ticks in Uganda where R. conorii had previously been reported by Socolovschi et al [29] as being prevalent. Similarly, Angerami et al ( [31] reported ATBF in a Brazilian who visited South Africa upon his return to Brazil. He had eschar and symptoms characteristics of ATBF which was confirmed by both immunological and molecular diagnostic methods to be infected by R. africae.…”

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp. in some communal farms in the Eastern Cape Province, South Africa

“…Furthermore, about nine pathogenic Rickettsia species (R. africae, R. parkeri, R. mongolotimonae, R. conorii, R. honei, R. rickettsii, R. raoultii, R. australis, and R. rhipicephalis) belonging to the spotted fever group Rickettsiae were detected in different tick samples collected in this study. R. africae had been previously reported from ticks removed from different animals and humans in South Africa, thus its detection was expected [35,36,37], from its well-known vector; A. hebraeum. Subsequently, about 24 sequences, from the 74 obtained sequences for ompB gene of Rickettsia sp., showed between 98.9% -99.3% homology with Rickettsia parkeri (KY124259, CP003341, AF123717, and KY1131111).…”

“…As a rare acute and multi-systemic febrile disease, spotted fever has been described to have mortality rate of over 50% in the absence of proper prophylaxis [33]. A. hebraeum with a signi cant aggression for biting humans has been documented as a well-known vector of Rickettsia africae, a zoonotic tick-borne bacterial pathogen that is the etiologic agent of African tick-bite fever in sub-Sahara Africa with a morbidity rate of > 50% [34,35]. Thus, R. africae infection has been described, after malaria, to be liable for most febrile illnesses diagnosed in tourists returning from southern Africa [17,36].…”

Evidence of pathogenic zoonotic tick-borne Rickettsia and Borrelia spp.  in some communal farms in the Eastern Cape Province, South Africa

“…As a rare acute and multi-systemic febrile disease, spotted fever has been described to have mortality rate of over 50% in the absence of proper prophylaxis (Prado et al, 2018). A. hebraeum with a significant aggression for biting humans has been documented as a wellknown vector of Rickettsia africae, a zoonotic tick-borne bacterial pathogen that is the etiologic agent of African tick-bite fever in sub-Sahara Africa with a morbidity rate of > 50% 47 . Thus, R. africae infection has been described, after malaria, to be liable for most febrile illnesses diagnosed in tourists returning from southern Africa 21,34 .…”