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Biomedical subjects

J G Olson

Publications and source records attributed to J G Olson.

84 records · Page 5Linked to original sources
PubMed1979

Forecasting the onset of a scrub typhus epidemic in the Pescadores Islands of Taiwan using daily maximum temperatures.

Daily maximum atmospheric temperatures were used to forecast the seasonal onset of scrub typhus in the Pescadores Islands of Taiwan. The day of the year on which the temperature first reached 30 degrees C was selected as the predictive base. Predictions for 1977 closely matched observed events. The model provides an easy and effective means to forecast the start of scrub typhus epidemics in the Pescadores Islands and could be used for such practical purposes as determining when prophylactic antibiotics should be administered to subjects whose risk of infection with Rickettsia tsutsugamushi is high.

Disease Outbreaks↗
PubMed1977

Epidemiological and serological study of scrub typhus among Chinese military in the Pescadores islands of Taiwan.

An outbreak of 69 cases of scrub typhus occurred among Chinese military personnel stationed in the Pescadores Islands, Taiwan Province, Republic of China between May and November 1975. A retrospective epidemiological study of this outbreak indicated that military personnel over 40 were more likely to have scrub typhus than those under 40. High risk groups included the Garrison Force (home guard), anti-aircraft gunners and infantry and armoured units stationed at Hsing-jen. The onset of symptoms in 69% occurred within one year of residence in the Pescadores. The clinical course of scrub typhus and the serological response to infection were also studied. Eschar formation, fever, headache chills and lymph node enlargement were the predominant clinical manifestations noted. The indirect immunofluorescent antibody test (IFAT) demonstrated diagnostic (four-fold) rises in antibody titres to Rickettsia tsutsugamushi reference strains in 36 of 41 paired sera tested. 11 of 19 patients from whom only single sera were obtained had IFA titres presumptive of scrub typhus (greater than or equal to 1:160). Of 19 patients experiencing possible primary infections, 13 (68%) responded with antibodies directed against more than one reference strain of R. tsutsugamushi. These results suggest that several antigenically diverse strains of R. tsutsugamushi may be active in the Pescadores.

Animals↗
PubMed1977

Rickettsia tsutsugamushi infection and scrub typhus incidence among Chinese military personnel in the Pescadores Islands.

Personnel assigned to infantry units of the army of the Republic of China (Taiwan) stationed in the Pescadores Islands experienced the highest incidence rate of scrub typhus (4%) and the highest rate of Rickettsia tsutsugamushi infection (12%) of the units studied during 1976. The ratio of scrub typhus to infection with R. tsutsugamushi was 30%. Non-immune personnel, when infected, were more likely to develop scrub typhus than were those who had previously been infected. There was a correlation between clinical illness and high antibody titers developed in response to the infection.

Humans↗
PubMed1976

Epidemic appearance of a new influenza strain in Asia.

An outbreak of influenza associated with increased absenteeism among school-age children occurred during May and June 1975 in Tapei, Taiwan. The virus strain has recently been shown to be antigenically similar to A/Victoria/3/75 which is now active in other areas of the Pacific.

Adolescent↗
PubMedDate not supplied

A serological survey of rural dogs and cats on the southwestern Canadian prairie for zoonotic pathogens.

A survey for antibodies against agents of plague, tularemia, and Rocky Mountain spotted fever (RMSF), and against Sin Nombre hantavirus (SNV), Bartonella henselae and B. clarridgeiae was conducted in the summer of 1995 using serum from rural dogs and cats living in the vicinity of four public parks in southeastern Alberta and southwestern Saskatchewan. Antibodies to all pathogens were detected in all survey areas. Overall prevalence rates were 0.075 for Yersinia pestis, 0.089 for Francisella tularensis, 0.025 for Rickettsia rickettsii (dogs only), and 0.029, 0.178 and 0.186 for SNV, B. henselae and B. clarridgeiae, respectively (cats only). This serological survey of rural dogs and cats was more sensitive and efficient than previous surveys based on collection and culture of rodents and ectoparasites. All six pathogens appear endemic to the region. Surveillance for plague, tularemia, RMSF and SNV, and management of associated public risks should be done in endemic regions.

Animals↗
PubMedDate not supplied

[Plasmodium falciparum travels by train from Ethiopia to Djibouti].

To investigate the role of the Djibouti-Ethiopian railway as a potential vehicle for inter-regional spread of malaria vectors and malaria parasites, we performed a double-sided study, both entomological and parasitological, during November 1989, at the frontier post of Guelile where the trains from Ethiopia enter the Republic of Djibouti. No malaria-transmitting mosquitoes were collected either from the daily passenger train or from the weekly vegetables train. One hundred and five passengers entering Djibouti by train from Ethiopia had a thick film examined for malaria parasites. Five smears were positive for Plasmodium falciparum, among them two showed gametocytes. We conclude that the railway may be an effective route for the propagation of the human malaria parasite between Ethiopia and Djibouti. Indeed, passengers infected abroad could import plasmodia into Djibouti and thus become the index cases for local malaria outbreaks, in case the climatic and entomological prerequisites essential for sustaining malaria transmission are present.

Animals↗
PubMedDate not supplied

[Dissimilar glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in the Afars and the Somalis of Djibouti].

In order to determine the prevalence of deficient activity of the enzyme glucose-6-phosphate dehydrogenase (G-6-PD) among the inhabitants of the east African Republic of Djibouti, we analyzed by the methaemoglobin reduction test the blood of 170 Djiboutian males, 81 Afars and 89 Somalis. Eight subjects were found to be G-6-PD deficient, 1 Afar and 7 Somalis (1.2% versus 8%; P = 0.02). We conclude that in Djibouti, health care providers should consider the presence of potential G-6-PD deficiency in their patients, especially in males of the Somali ethnic group. Indeed, many medications are contraindicated in the G-6-PD deficient subjects, and primaquine and pyrimethamine-sulfadoxine (FANSIDAR) have to be considered dangerous anti-malarial drugs for Somali males as long as their level of G-6-PD activity has not been determined. Since in Djibouti many acute falciparum cases are presenting with severe icteric anaemia, we hypothesize that some of these haemolytic anaemias might not be caused by the parasitic infection alone, but that some malaria patients might become aggravated through the administration of haemolytic drugs in case they are G-6-PD deficient. Finally, we propose that our study should be expanded to include the systematic determination of the variants of the enzyme in all subjects found G-6-PD deficient, since the clinical manifestations of G-6-PD deficiency are directly related to the type of variant present.

Antimalarials↗
PubMedDate not supplied

Use of Bartonella antigens for serologic diagnosis of cat-scratch disease at a national referral center.

BACKGROUND: Bartonella henselae (formerly the genus Rochalimaea) has recently been isolated from patients with cat-scratch disease and their cats, and since September 1992 the Centers for Disease Control and Prevention has offered an indirect fluorescent antibody assay for Bartonella-specific antibody. METHODS: Physicians submitted serum samples from patients suspected of having cat-scratch disease or other Bartonella-associated illness and completed a questionnaire that recorded clinical information. Indirect fluorescent antibody assay was performed with the use of antigen derived from three Bartonella species: B henselae, Bartonella quintana, and Bartonella elizabethae. RESULTS: During 16 months, 3088 serum samples were received. The largest numbers of specimens and the highest percentages positive (titer, > or = 64) were observed in the fall and winter. Clinical histories of the first 600 patients for whom serum samples and completed information forms were received were examined in detail; seropositivity was significantly associated with cat contact, cat age of less than 1 year, cat scratch, presence of an inoculation papule, and regional adenopathy. Of 91 patients whose illness met a strict clinical definition of cat-scratch disease, 86 (95%) had titers of 64 or greater to either B henselae or B quintana. A fourfold rise or fall in titer was observed in 87 of 132 patients with paired serum samples. CONCLUSIONS: The indirect fluorescent antibody assay for Bartonella-specific antibody is sensitive for the diagnosis of cat-scratch disease. Redefinition of cat-scratch disease on the basis of cause and use of this assay as a diagnostic criterion is recommended.

Adolescent↗