Detection of Rickettsia Africae in Patients and Ticks Along the Coastal Region of Cameroon

Abstract

Rickettsia africae was identified in seven (6%) of 118 patients with acute fevers of unknown etiology proven not to be malaria or typhoid fever from clinics along the coastal region of Cameroon by polymerase chain reaction (PCR) amplification and sequencing of the citrate synthase (gltA) and outer membrane protein A (ompA) genes of Rickettsia. The majority (71%) of the patients were female. Clinical manifestations included fever (100%), headache (71%), myalgia (71%), arthralgia (43%), pulmonary involvement (29%), and diffuse rash (14%). Moreover, R. africae was detected by PCR amplification and sequence analysis of the gltA and ompA genes in 62 (75%) of 83 adult Amblyomma variegatum ticks collected from cattle in the same region. These results confirm the presence of a previously unrecognized infectious disease in the indigenous Cameroonian population, as well as extend the established range of R. africae.

Molecular screening of ticks for the presence of Rickettsia species: A public health concern

“…The most likely reason for the dissimilarities in our findings could be attributed to the differences in protocols as different primer pairs we adopted in the studies. Other SFG rickettsial that have been detected in South Africa include Rickettsia conorii conorii, R. aeschlimannii and R. sibrica monogolitimonae [51,52] of which none was detected in our study.…”

Tick-Borne Rickettsioses around the World: Emerging Diseases Challenging Old Concepts

“…Despite high seroprevalence to R. africae among native Africans, nearly all acute cases of ATBF described in the literature have occurred in European or American travelers (145,205,273). Recently however, Ndip et al reported cases of ATBF documented by serology (26 patients) and molecular techniques (7 patients) among indigenous patients in Cameroon (212,213).…”

Human Ehrlichioses and Rickettsioses in Cameroon

“…Efforts to determine the epidemiology and ecology later re-emerged in 2004 when anti-rickettsial IgM antibodies were detected in some Cameroonian patients along the coastal region of Cameroon (Ndip et al, 2004a). These results were further confirmed by detection of R. africae DNA in about 6% of acutely ill febrile patients (Ndip et al, 2004b). Human infections or the agent has been detected in all regions of southern Cameroon where epidemiologic investigations have been made (Figure 3).…”

“…The agent was later isolated in A. hebraeum ticks in Zimbabwe in 1990, and in 1992, the first isolate from a patient was obtained Kelly et al, 1994). The pathogen has been detected in many other African countries including Senegal , Ethiopia (Stephany et al, 2009) and Cameroon (Ndip et al, 2004a;Ndip et al, 2004b). In the following, we give a synopsis of our current knowledge of African tick bite fever in Cameroon.…”

“…Ixodid ticks (hard ticks) of the genus Amblyomma have been recognized as the vectors (Kelly, 2001). In Cameroon, A. variegatum (Figure 1b) www.intechopen.com has been identified as the potential vector with about 75% of ticks (male and female) collected from cattle found to be infected with R. africae (Ndip et al, 2004b). Reports from other studies have indicated that R. africae infection in Amblyomma ticks frequently has a high prevalence (up to 100%) reported in ticks collected in some disease-endemic countries (Dupont et al, 1994;Parola et al, 2001).…”