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One presented IgG antibody titre of 128 and IgM antibody titre of 32 and the other two seroreactive sera presented IgG antibody titre of 256 and IgM antibody titre of 32

One presented IgG antibody titre of 128 and IgM antibody titre of 32 and the other two seroreactive sera presented IgG antibody titre of 256 and IgM antibody titre of 32. and IgG antibodies with endpoint titres of 128 and 256. These findings supported a diagnosis of exposure amongst these patients and highlight that rickettsioses may be among the cause of unknown febrile syndromes in Angola. Therefore, physicians must be aware of this reality and must include this vector-borne disease as part of aetiologies that should be considered and systematically tested in order to delineate appropriate strategies of diagnostic and control of in Angola. 1. Introduction Rickettsioses are vector-borne diseases of medical importance, particularly in African countries where an increasing number of cases have been reported amongst residents and tourists [1]. Despite its public Rabbit Polyclonal to Cytochrome P450 4F3 health importance, the epidemiological characteristics linked Trichostatin-A (TSA) to rickettsial diseases are poorly defined in the African continent [2]. species are strictly intracellular, Gram-negative bacteria from the order Rickettsiales comprising 30 recognized species and numerous uncharacterized strains [3]. Ticks are vectors Trichostatin-A (TSA) and reservoirs for several rickettsial agents, but some spp. are transmitted by fleas, lice, and mites Trichostatin-A (TSA) [4]. These bacteria present several antigenically distinct groups, with those belonging to the spotted fever group (SFG) remaining an important cause of human and animal diseases, characterized by vascular invasion and tissue necrosis [5]. The classical triad of clinical manifestations of SFG infection includes fever, eschar, and rash [6]; however, these vary depending on the rickettsial species involved. In Angola, a high percentage of the population lives in suburban neighbourhoods, characterized by adobe and cement constructed houses with limited access to public basic resources such as potable water, energy supply, health, and education. These highly unhealthy living conditions associated with domestic animals in close proximity increase the exposure to ectoparasites and to the pathogens that they might harbour. Many studies report rickettsioses acquired by travellers, but the majority refers to sub-Saharan Africa tourists who develop African tick-bite fever (ATBF) [1]. In African countries, fevers of unknown origin can have different aetiologies including rickettsial infection but, due to the overlapping symptomatology with other endemic diseases (e.g., malaria, dengue, HIV, and brucellosis) that also cause fever, as well as the lack of available diagnostic tests and laboratory resources [7], rickettsioses are often underdiagnosed [2]. The aim of this study was to perform the laboratory diagnosis of spp. exposure among febrile patients from Angola with malaria and yellow fever already clinically and laboratory discarded. 2. Methods 2.1. Sample Collection Between February 2016 and March 2017, a total of 87 serum specimens were obtained from public hospitals, as part of the Febrile Syndrome Surveillance Programme of Angola. These serum specimens were collected from patients from different cities (Benguela, Cabinda, Huambo, Luanda, and Malanje) and provinces (Hula, Kwanza Sul, Kwanza Norte, Lunda Norte, and Zaire) of Angola and were selected for this study if belonging to individuals presenting fever for at least four days (37.5C) and with at least one of the following inclusion criteria: malaise, myalgia, arthralgia, nausea, vomiting, and rash. These selected serum specimens were also malaria and yellow fever negative, previously tested through peripheral blood smear, malaria antigen detection test (SD BIOLINE), and RT-PCR, respectively. A questionnaire including patient demographic (age and gender) and epidemiological data (province and municipality of origin, type of residence, household characteristics, season of specimen collection, access to potable water, contact with animals, and clinical manifestations) was filled for each patient by the health care professionals. 2.2. Serological Testing Sera were tested by an in-house immunofluorescence assay (IFA) using strain as antigen, prepared at the Portuguese National Institute of Health Dr. Ricardo Jorge, as previously reported [8]. Along with fever, exposure was defined when the sera presented both IgG titre 64 and IgM titre 32, according to.