Spotted fever group rickettsiae in southern Africa--a review and current concepts

Until recently our understanding of spotted fever group (SFG) rickettsioses in southern Africa was based on research carried out in the 1930s and 1940s. In the last decade there have been considerable advances in the techniques available to study rickettsias and the application of these in southern Africa has greatly increased our knowledge of the organisms in the region and the epidemiology of diseases they cause. In this review we describe the new advances used to study rickettsias and the current data available on SFG rickettsioses in the region.     

Two cases of spotted fever group rickettsiosis contracted in southern parts of Africa

The effect of Ogi-Keishi-Gomotsu-To-Ka-Kojin (OKGK), a traditional Chinese herbal medicine (Kampo medicine), on cholesterol metabolism was studied in male Sprague-Dawley rats. Intake of OKGK at doses of 1.38 g/kg for 4 weeks significantly reduced total cholesterol levels in the serum and liver of hypercholesterolemia rats fed a cholesterol-enriched diet. OKGK suppressed cholesterol absorption through the intestine and stimulated excretion of cholesterol into feces as bile acids. Biochemical study indicated that OKGK treatment enhanced cholesterol 7alpha-hydroxylase activity the rate limiting enzyme of cholic acid synthesis, in the liver without any effect on the rate limiting enzyme of cholesterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. Further, cholesterol-enriched diet containing cholic acid suppressed cholesterol 7alpha-hydroxylase activity, whereas OKGK administration reversed the suppression. In conclusion, these results supported the idea that OKGK may be an effective agent for treatment of patients with hypercholesterolemia.     

Spotted fever imported into Norway in 1997

Tick-borne rickettsioses are important zoonoses in many tropical and subtropical areas. There has recently been an increase in the number of reported cases among tourists returning to Scandinavia. In this article we present all five serologically confirmed cases of tick-borne rickettsioses imported into Norway in 1997. The patients were Norwegian tourists who had visited South Africa (three cases), Zimbabwe, and Italy. Four cases had typical eschar and three had maculopapular exanthema. The patients were treated with either doxycycline or ciprofloxacin. No complications were reported. The diagnosis of tick-borne rickettsiosis was confirmed by the detection of specific IgM antibodies to Rickettsia conorii using micro-immunofluorescence in serum samples.     

Spotted fever after travel to South Africa

Three patients developed fever, malaise and a typical maculopapular rash a few days after returning to Norway from South Africa. In South Africa they had been bitten by ticks several times while hunting. Two patients, with lesions compatible with eschar, were hospitalized, and a diagnosis of rickettsial spotted fever was established based on the clinical presentation and positive Rickettsia conorii serology. Rickettsial diseases are extremely rare in Scandinavia, and a survey on rickettsioses is presented in this paper.     

Carbamazepine hypersensitivity and rickettsiosis mimicking Kawasaki disease

We report on two patients whose clinical presentation resembled that of Kawasaki disease. The first patient was a boy with epilepsy, whose symptoms first appeared following treatment with carbamazepine. The second boy had Mediterranean Spotted Fever. The significance of medical history in avoiding overdiagnosis of Kawasaki disease is emphasized.     

Antigenic relationships among phlebotomus fever group arboviruses and their implication for the epidemiology of sandfly fever

The antigenic relationships of 21 known or presumed Phlebotomus fever group serotypes and of 2 ungrouped, solvent sensitive, sandfly-associated arboviruses (Pacui and Charleville) were studied by complement fixation, plaque neutralization, and hemagglutination-inhibition methods. Results of complement fixation and neutralization tests were specific, allowing clear separation of the various serotypes, while those of the hemagglutination-inhibition test showed broader crossing and lack of specificity. Pacui virus was shown to be a member of the Phlebotomus fever serogroup. Six new Phlebotomus fever group serotypes are also described, increasing the known members of the group to 22. The implications of these and other recent data about the epidemiology of sandfly fever are discussed.     

Role of T lymphocyte subsets in immunity to spotted fever group Rickettsiae

To evaluate the roles of CD4 and CD8 T lymphocytes in immunity to disseminated endothelial infection with Rickettsia conorii (Malish 7 strain), these T cell subsets were depleted or adoptively transferred into subsequently infected C3H/HeN mice. CD4 T lymphocyte-depleted and sham-depleted mice underwent a similar course of illness with a sublethal rickettsial dose, cleared the infection by day 10, and recovered on days 10 to 11. In contrast, mice depleted of CD8 lymphocytes or CD4 and CD8 lymphocytes died or remained persistently infected through day 15 with the ordinarily sublethal dose. Endothelium was the major site of rickettsial persistence, including sites in the vital organs, brain, and lungs of CD8 lymphocyte-depleted mice. In nondepleted animals, CD8 T lymphocytes were observed in apposition to endothelial cells on day 10 at the time of rickettsial clearance. Adoptive transfer of immune CD4 or CD8 T lymphocytes protected mice against a lethal dose of R. conorii in the disseminated endothelial target model. Nonimmune CD4 or CD8 lymphocytes and immune lymphocytes that had passed through columns that depleted both CD4 and CD8 lymphocytes failed to protect mice against R. conorii. These studies represent the first analysis of the role of T lymphocyte subsets in immunity to spotted fever group rickettsiae and the first demonstration that clearance of spotted fever group rickettsiae from endothelial cells requires immune CD8 T lymphocytes.     

Genotypic identification and phylogenetic analysis of the spotted fever group rickettsiae by pulsed-field gel electrophoresis

Using pulsed-field gel electrophoresis, we studied the chromosomes of spotted fever group rickettsiae. We digested the DNA of 16 species currently known to belong to this group with SmaI, EagI, and BssHII. The genome size of 13 rickettsiae was between 1,200 and 1,300 kb. "Rickettsia massiliae" and "R. helvetica" genome sizes were 1,370 and 1,397 kb, respectively, and that of R. bellii was 1,660 kb. It was possible to obtain distinctive patterns for each species, but in R. conorii, 10 isolates exhibited the same profiles, showing that pulsed-field gel electrophoresis is a good interspecies identification tool. We achieved a phylogenetic analysis of these bacteria by using the Dice coefficient and UPGMA and Package Philip programming. We established a dendrogram of the genetic relationships between the different species showing the existence of a cluster in the spotted fever group rickettsiae including R. conorii, R. rickettsii, R. parkeri, R. sibirica, "R. africae," "R. slovaca," Thai tick typhus rickettsia, and Israeli tick typhus rickettsia. We located three genes previously cloned and sequenced (genes encoding the R. rickettsii surface proteins of 120 and 190 kDa and the R. prowazekii citrate synthase gene), using Southern hybridization. The genes encoding citrate synthase and the surface protein of 190 kDa were usually located on the same band, and it is hypothesized that they are relatively close on the chromosome.     

Isolation of Legionella and free-living amoebae at hot spring spas in Kanagawa, Japan

Microbiological contamination of hot spring bath water is a public health concern. A province-wide survey was carried out to determine the extent and distribution of both Legionella and free-living amoebae contamination. Among 30 samples of hot spring bath from 12 sites in Kanagawa, Japan, L. pneumophila was detected in 21 water samples from 11 sites, ranging from 10(1)-10(3) CFU/100 ml. Serogroups 3, 5 and 6 of L. pneumophila were predominantly isolated from the samples. Naegleria (46.7%), Platyamoeba (33.3%), Acanthamoeba (10.0%) and 2 other genera of free-living amoebae were detected in 22 samples from 11 sites. One or more genera of host amoebae of Legionella occurred in 17 samples (56.7%) from 9 sites. Another thing to be noted is that 13 water samples contained N. lovaniensis. Although N. lovaniensis is nonpathogenic, it is considered an indicator organism for places that are suitable for the growth of N. fowleri, a causative agent of primary amoebic meningoencephalitis in man.     

Seroprevalence of Bartonella henselae and Toxoplasma gondii infections among pet cats in Kanagawa and Saitama Prefectures

Seroprevalence of Bartonella henselae and Toxoplasma gondii was investigated among 471 pet cats obtained from seven private animal hospitals in Kanagawa and Saitama Prefectures during the period from May 1994 to June 1995. 'Furthermore, 67 randomly selected from the 471 serum samples were examined for the feline immunodeficiency virus (FIV) antibody and feline leukemia virus (FeLV) antigen. The antibody to B. henselae was examined by an indirect immunofluorescent antibody test. T. gondii, FIV and FeLV infections in cats were detected with respective commercial kits. Of the cat serum samples tested, 43 (9.1%) were found to be seropositive for B. henselae and 41 (8.7%) for T. gondii. The B. henselae-positive rate (12.9%) of male cats was significantly higher than that (5.2%) of female cats. On the other hand, T. gondii-positive rate was 9.1% in male and 8.7% in female cats and there was no significant difference in the positivity between sexes. The positive rate in each hospital varied from 0 to 19.5% for B. henselae and 4.9 to 18.8% for T. gondii. The ages of B. henselae- and T. gondii-positive cats were distributed from < 1-year-old to 14-year-old and the seropositivity increased with age of cats. Of the 67 cat serum samples, 16 and 6 cases were positive for FIV and FeLV, respectively. There was no relationship between these viral and B. henselae infections in cats.     

Taxonomic relationships among spotted fever group rickettsiae as revealed by antigenic analysis with monoclonal antibodies

The spotted fever group (SFG) is made up of more than 20 different rickettsial species and strains. Study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. In this study, we determined taxonomic relationships among the SFG rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. A total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodominant proteins or on the lipopolysaccharide-like antigens of strains of Rickettsia africae, Rickettsia conorii, Rickettsia massiliae, Rickettsia akari, Rickettsia sibirica, and Rickettsia slovaca, were used in the study. The distribution and expression of the epitopes among 29 SFG rickettsiae and Rickettsia bellii were assessed by determination of reaction titers in a microimmunofluorescence assay. The results were scored as numerical taxonomic data, and cluster analysis was used to construct a dendrogram. The architecture of this dendrogram was consistent with previous taxonomic studies, and the implications of this and other findings are discussed.     

Isolation of a spotted fever group rickettsia from the Pacific Coast tick, Ixodes pacificus, in Oregon

A rickettsia of the spotted fever group was isolated on three occasions from Ixodes pacificus in western Oregon. These isolations, and additional evidence furnished by complement fixation tests on guinea pigs inoculated with other Oregon ticks of this species, indicate that the association of this rickettsia with the Pacific Coast tick may be widespread. This is the first isolation of a spotted fever group rickettsia from I. pacificus. Because the Oregon isolates are mildly virulent for guinea pigs they resemble the Western U and Rickettsia montana strains of rickettsiae. However, preliminary evidence from cross-immunofluorescence tests of mouse antisera suggests the Tillamook and Grants Pass strains are antigenically different from all known spotted fever group agents.     

Concurrent dengue hemorrhagic fever and typhoid fever infection in adult: case report

In Indonesia as well as in many developing countries both typhoid fever and dengue hemorrhagic fever (DHF) are still endemic and prevalent. In Indonesia the incidence of DHF in 1994 was 9.72/100,000 population with CFR of 2.5% and each year about 640,000-1,500,000 cases of typhoid fever were reported with mortality of 1.6-3%. The concurrent infection of both diseases may occur in one patient.     

Eczema and hay fever in schoolchildren

In a questionnaire survey of 2,813 children aged 4 to 19 years, eczema prevalence was 7.8% but rose to 21.3% in those with asthma. The prevalence was 5.9% in non-asthmatics. The hay fever prevalence was 12.3% but rose to 36% in those with asthma. The prevalence was 8.9% in non-asthmatics. Hay fever was more common in urban than rural children, but there was no town/country difference for eczema.