Reemergence of Rickettsiosis in Oran, Algeria

Abstract

The presumptive cases of Mediterranean spotted fever have been identified in 1993 and since that time, its frequency has steadily increased. The prospective study, in summer 2004, was conducted in order to present the descriptive clinic and epidemiology, to identify more severe forms, the presence of the multiple eschars, and different rickettsial strains caused the disease in our region. In Oran, the cases were diagnosed clinically. In Marseille, serum specimens were tested by IFA using the panel of eight rickettsial antigen; Western blot and cross-adsorption studies were also performed in order to confirm the diagnosis. Ninety-three patients clinically diagnosed were recorded from July 3 to October 28, 2004. Eighty percent were male, the mean age was 44.3 years, 90% were exposed to dog and 32% reported tick bites. Clinical signs were as follow: presence of underlying disease (44%), sudden onset (78%), fever (100%), loss of weight (63%), conjunctivitis (43%), and a tache noire was noticed in 70%. Interestingly, two patients had two and three eschars, respectively. The rash was maculopapular (palm and sole) and purpuric in nine cases. Doxycycline was the most antibiotic (91%) with favourable outcome in 91% of the cases. Malignant form with death is reported for three patients (3.2%). Among the 93 patients, 104 serum from 65 patients were tested (serums of others patients were lost or ticket not found on tube. Sixty-three patients out of 65 had a positive serology by IFA with cross-reactive antibodies especially between R. conorii, R. felis and/or R. typhi. Two others negative serology were: one precocious serum and second from the patient, which presented symptoms of MSF and tested two serums, Western blot and cross-adsorption.

Questions on Mediterranean Spotted Fever a Century after Its Discovery

“…However, in 1995, a peak of MSF disease with 236 cases was noticed in this country and reached 716 cases in 1997 (12). In Oran, Algeria, the fi rst case of MSF was diagnosed in 1993; since that time, the number of cases has steadily increased to reach 134 in 2004 (2). Figure 4 illustrates the distribution and incidence of R. conorii conorii infection in countries where MSF is endemic.…”

“…For example, in Oran, Algeria, the fi rst case of MSF was clinically diagnosed in 1993. Since that time, the number of cases has steadily increased (2). In some other countries of the Mediterranean basin, such as Italy and Portugal, incidence of MSF has substantially increased in the past 10 years.…”

Rickettsia aeschlimanniiInfection, Algeria

“…In North Africa, cases of rickettsioses are rarely documented (2). In Algeria, only Mediterranean spotted fever caused by R. conorii has been described (3).…”

“…Serum samples were sent to Marseille, France, where they were analyzed by an IF assay, using 9 SFG rickettsial antigens (R. conorii conorii, R. conorii israelensis, R. africae, R. sibirica mongolitimonae, R. aeschlimannii, R. massiliae, R. helvetica, R. slovaca, and R. felis) and a typhus group antigen (R. typhi) (3). The IF assay result was considered positive 1) if immunoglobulin (Ig) G titers were >128 and/or IgM titers were >64 for R. conorii and 2) if IgG titers were >64 and/or IgM titers were >32 for other rickettsial antigens (3). When cross-reactions between several antigens were noted, rickettsial antigen was considered to represent the infectious agent if titers of IgG and/or IgM antibody against this antigen were at least 2-fold higher than titers of IgG and/or IgM antibody against other rickettsial antigens (3,4).…”

“…The IF assay result was considered positive 1) if immunoglobulin (Ig) G titers were >128 and/or IgM titers were >64 for R. conorii and 2) if IgG titers were >64 and/or IgM titers were >32 for other rickettsial antigens (3). When cross-reactions between several antigens were noted, rickettsial antigen was considered to represent the infectious agent if titers of IgG and/or IgM antibody against this antigen were at least 2-fold higher than titers of IgG and/or IgM antibody against other rickettsial antigens (3,4). When the difference in titers among several antigens was lower than 2-fold, WB assays and cross-adsorption studies were performed (4,5).…”