Clinical and laboratory findings of spotted fever in Israeli children.

In a prospective study of 70 Israeli children with spotted fever the major clinical features were fever (100%), skin rash (98.5%), myalgia (54%) and vomiting (40%). Thrombocytopenia (75%) and hyponatremia (62.5%) were common, but were not associated with increased mortality. Antibodies to Rickettsia conorii were detected by the indirect immunofluorescent antibody assay. In one patient Rickettsia was grown from blood. Contacts with dogs were reported in 17 of 40 patients questioned, and in only 2 was a canine tick bite obvious. Hospitalization was required in 11 (16%) patients. There was 1 fatality. The rickettsia responsible for spotted fever in Israel appears to be an antigenic variant of R. conorii. Early recognition and treatment of this disease permits rapid eradication of the rickettsiae and facilitates complete recovery.

Serological cross-reactions between Rickettsia typhi, Proteus vulgaris OX19, and Legionella bozemanii in a series of febrile patients.

The sera of 19 patients with a febrile disease of undetermined etiology were positive in the indirect immunofluorescence assay (IFA) to Legionella bozemanii serogroup 1 (Lb) and Rickettsia typhi (Rt). To both antigens, high titers of IgG-class and IgM-class antibodies were demonstrated. Several of the patients also had positive IFA and Weil-Felix reactions to Proteus vulgaris OX19 (PX 19). A sharp reduction of the serotiters to all three antigens was achieved by absorption of the sera with any one of the organisms. We demonstrated, by crossed immunoelectrophoresis with an Lb extract and a rabbit reference anti-Lb serum, that a heat-stable and trypsin-resistant antigen (antigen no. 1) reacted consistently with patients' sera that had been incorporated into an intermediate gel. Sera from five patients with high-titer IFA reactions to Rt, but no reaction to Lb, showed no interaction with antigen no. 1.

Prevalence of antibodies to Legionella species in a series of patients in Israel.

A collection of serum specimens from 77 patients at various hospitals or clinics in Israel was used to determine the usefulness of the enzyme-linked immunosorbent assay (ELISA) with a multivalent antigen for the detection of legionella antibodies. Rickettsial infection rather than legionellosis was suspected in most of these patients. The multivalent antigen was derived from Legionella pneumophila serogroups 1-6, L. bozemanii WIGA, and L. micdadei TATLOCK. A preliminary test of the multivalent antigen with specific rabbit antisera had shown that homologous reactions were not appreciably reduced in strength or specificity by the presence of the heterologous antigens. The results with the human sera revealed that 28 patients (36%) had reciprocal dilution titers greater than or equal to 1,280 and 43 (56%) had titers greater than or equal to 320. Tests with univalent antigens identified L. bozemanii as the only or principal antigen reacting with 13 of these sera. In contrast to the sera reacting with other legionella antigens, the great majority (11 of 13) of L. bozemanii-positive sera reacted also with Rickettsia typhi. The data suggest that most, but not all, reactions with L. bozemanii were elicited by a cross-reacting R. typhi antigen. These results were confirmed by cross-absorption tests.

Spotted fever and murine typhus in the Negev desert region of Israel, 1981.

During 1981, 52 cases of rickettsiosis caused by the spotted fever group of rickettsiae were reported in a population of 250 000 living in the Negev desert region of Israel. Retrospectively, at least 5 of these cases were serologically shown to have been caused by Rickettsia typhi, the agent of murine typhus. Most cases of rickettsial disease occurred in the summer months and one half of all cases occurred in children aged 9 years or less. While the specificity of a physician's diagnosis of the rickettsial diseases appears to be high (i.e., few cases of other diseases are misdiagnosed as either spotted fever or murine typhus), the sensitivity of the physician's diagnosis may be lower (i.e., many cases of these diseases presenting as fevers of unknown origin are not diagnosed as rickettsial disease). These findings may also be important for other countries of the region.

Rickettsial antibody prevalence in southern Israel: IgG antibodies to Coxiella burnetii, Rickettsia typhi, and spotted fever group rickettsiae among urban- and rural-dwelling and Bedouin women.

A retrospective serological survey was carried out using sera obtained from women at childbirth in the southern desert region of Israel to determine exposure experience to three rickettsial agents: Coxiella burnetii, Rickettsia typhi, and spotted fever group rickettsiae. Using the indirect fluorescent antibody method for determining IgG antibodies, it was found that about 40% of all sera examined demonstrated antibodies to one or more rickettsiae. Bedouin women appeared to be at greater risk of having antibodies to C. burnetii and spotted fever group rickettsiae than did Jewish residents of Beersheba, agricultural settlements, and development towns. The residents of development towns appeared to be at lower risk of developing antibodies to spotted fever group rickettsiae than did other populations sampled. Possible reasons for these differences are discussed.

Preparation and use of erythrocyte-globulin conjugates to Lassa virus in reversed passive hemagglutination and inhibition.

Conditions were defined for functional covalent coupling of anti-Lassa virus globulins to glutaraldehyde-fixed chicken erythrocytes. Tolylene-2,4-diisocyanate in a reaction mixture containing not more than 0.01 M NaCl produced uniformly good conjugates which were used in reversed passive hemagglutination (RPH) and reversed passive hemagglutination inhibition (RPHI) tests to detect Lassa virus antigens in infected cell cultures and specific antigens in Vero cell cultures. Identical results were obtained with this method and with immunofluorescent-antibody (IFA) staining in the detection and identification of Lassa virus isolated from human and rodent specimens from West Africa. The RPHI method was equal to IFA for serological diagnosis of acute human Lassa virus infection and superior to IFA, complement fixation, and a radioimmunoassay procedure for detection of Lassa virus antibodies in a human population where this infection is endemic.

Recrudescent typhus: fluctuations in titers of complement-fixing and microagglutinating antibodies to rickettsia prowazeki in persons with a history of epidemic typhus.

Abstract A study on recrudescent typhus was conducted among 294 volunteers most of whom had contracted typhus in Eastern Europe and who immigrated to Israel after the Second World War. The main aim of the study was to determine whether persons, once infected, might subsequently suffer relapses without clinical signs which could presumably serve as sources of the microorganism in the interepidemic period and might be responsible for the initiation of new epidemics. The selection of volunteers was based on the reliability of their histories and on the absence of murine typhus in their present environment. Those under study were interviewed at regular 2-3 months' intervals during which blood samples were taken from them. Six blood samples were obtained from 262 individuals and at least 3 samples from the rest. Complement-fixation and microagglutination tests were carried out in order to establish the presence of antibodies specific for epidemic typhus. In 12% of the volunteers no demonstrable antibodies were found, while 67% considered to have such antibodies showed no significant titer fluctuations. However, 21% of the volunteers exhibited 4- to 8-fold fluctuations in titer in at least one of the tests used-a result which suggests the possibility of serological relapse.