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Biomedical subjects

J D MacLean

Publications and source records attributed to J D MacLean.

At least 37 records · Page 2Linked to original sources
PubMed1993

Screening for schistosomiasis, filariasis, and strongyloidiasis among expatriates returning from the tropics.

The clinical utility of eosinophil determinations, stool examinations, and serological studies for detection of parasitic infection was examined in an asymptomatic expatriate population by retrospective chart review. The screened population consisted of 1,605 patients attending a tropical medicine clinic. The sensitivity of eosinophil counts as a screening test for infection with filaria, schistosomes, or Strongyloides stercoralis was 38%, and its positive predictive value was 9%. A cost-efficacy analysis of the use of three diagnostic tests in screening for infection with filaria (n = 23), schistosomes (n = 34), or Strongyloides (n = 7) was performed. The use of stool examination and serological screening together had a sensitivity of 89%, at a total cost similar to that of a conventional strategy involving a stool examination and an eosinophil count, which would have picked up only 61% of our cases. In this population, eosinophil counts contribute little to the diagnostic accuracy obtained with stool examination and serological screening, and the low specificity of eosinophil counts generates high costs.

Adolescent↗
PubMed1992

Epidemiologic and serologic definition of primary and secondary trichinosis in the Arctic.

A large outbreak of trichinosis acquired from walrus in Salluit in 1987 provided the immunologic and epidemiologic data from which two distinct clinical syndromes were identified. The first syndrome is the classic myopathic form with edema, fever, myalgia, and rash. The second is a persistent diarrheal illness with little edema or myalgia. The clinical presentations are paralleled by distinct differences in type and development of antibody response. The clinical and serologic profiles of the two syndromes support the hypothesis that the myopathic form represents a primary infection of Trichinella nativa, while the second represents a secondary infection in previously sensitized individuals.

Adolescent↗
PubMed1992

Intestinal parasite infection in the Kampuchean refugee population 6 years after resettlement in Canada.

A follow-up prevalence study was done in 1989 of the same Kampuchean refugee population (247 subjects) that had been screened and treated for intestinal parasite infection 6 years earlier. A control group (102 subjects) included Kampuchean refugees who had arrived in Montreal at about the same time. These groups did not differ in age, sex, family size, or number of months spent in refugee camps. Statistically significant prevalence differences were observed in the rescreened group between 1982-1983 (63.7%) and 1989 (21.9%) and between the rescreened group and the control group (39.2%). These differences are largely attributable to the elimination of Ascaris infection and decreases in Giardia and hookworm infections. However, Strongyloides infection decreased only slightly (from 15% to 11%) in the rescreened group, while 12% of the control group was infected. Despite an early screening and treatment program, there remain important health risks in this immigrant population due to long-lived potentially pathogenic parasites.

Adult↗
PubMed1992

A case of human ehrlichiosis acquired in Mali: clinical and laboratory findings.

We report on the clinical, epidemiologic, and laboratory characteristics of the first case of human ehrlichiosis acquired outside the United States caused by an Ehrlichia sp. other than E. sennetsu. The patient, a 24-year-old woman, presumably acquired the infection in Mali in northern Africa; the diagnosis was made when she returned to North America. The patient reported a fever and diarrhea a week before she left Mali; the diarrhea resolved, but the fever and chills continued. She also reported intermittent tingling in both hands and feet and muscle discomfort. Her temperature was 37.8 degrees C and her pulse rate was 100 per minute. She had two erythematous maculopapules (0.5 x 0.7 mm) on her thigh and ankle that resembled infected insect bites. Her hemoglobin level was 148 g/l with normal indices, and her white blood cell count was 10, 500/mm3 with many atypical lymphocytes and platelets. This report is intended to increase physicians' awareness of ehrlichiosis in foreign travelers and other patients, and suggests the need for further research to determine the prevalence and distribution of this disease.

Adult↗
PubMed1990

An outbreak of toxoplasmosis in pregnant women in northern Québec.

An ongoing screening program for toxoplasmosis identified a cluster of four women from northern Québec who, over a 4-month period, seroconverted during their pregnancy. An epidemiologic investigation was carried out in an attempt to identify the source of this infection. All potential risk factors were assessed by a questionnaire administered to 22 Inuit women who had delivered babies in the previous year. Seroconversion was significantly associated with skinning of animals for fur (P = .015) and frequent consumption of caribou meat (P = .034). Compared to seronegative women, women who were seropositive were more than four times more likely to have eaten dried seal meat (P = .067), more than six times more likely to have eaten seal liver (P = .064), and more than eight times more likely to have consumed raw caribou meat more than once per week (P = .054). These observations have contributed to the development of guidelines for the prevention of toxoplasmosis in seronegative pregnant women in this arctic region.

Adolescent↗
PubMed1990

Seroepidemiology of Strongyloides infection in the Southeast Asian refugee population in Canada.

As part of a screening and treatment program for intestinal parasite infections offered to newly arrived Southeast Asian refugees in Canada between July 1982 and February 1983, a total of 232 sera were tested for Strongyloides infection using an enzyme-linked immunosorbent assay (immunoglobulin G). These results were compared with coprologic results and eosinophil counts. The seroprevalence was 76.6% (131 of 171) among Kampucheans, 55.6% (15 of 27) among Laotians, and 11.8% (4 of 34) among Vietnamese. A statistically significant relation (p less than 0.001) was found between Strongyloides serology and Strongyloides infection on stool examination (prevalence, 24.7%) among Kampucheans. Eosinophilia (greater than or equal to 10%) was found to be significantly associated with both infection measures. Using coprologic results as the "gold standard," the properties of the serologic test were estimated to be: sensitivity (95%), specificity (29%), positive predictive value (30%), and negative predictive value (95%). These estimates should be regarded as minimal values, as stool examination for Strongyloides infection can be an unreliable diagnostic reference. Further evaluation of the discrepancies observed between coprologic and serologic testing is required to determine the usefulness of these tests in epidemiologic studies.

Adolescent↗
PubMed1989

Trichinosis in the Canadian Arctic: report of five outbreaks and a new clinical syndrome.

Trichinosis is a serious but understudied medical problem in the Arctic. Forty-nine consecutive cases in the Inuit population of northeastern Canada are described. Most developed the disease after eating raw walrus, and the clinical presentation of most of these cases differed from previously reported descriptions of classic trichinosis due to Trichinella spiralis. Unlike the classic syndrome of a brief period of diarrhea followed by fever, myalgia, muscle weakness, and edema, the most common presentation in these cases was a prolonged diarrhea without fever and with brief muscle symptoms. High peripheral eosinophilia, high Trichinella antibody serotiters, and little direct or indirect evidence of muscle invasion in many of those with the chronic diarrheal presentation suggest a new clinical syndrome due to a different species of Trichinella seen in the Arctic or to reinfection with Trichinella.

Animals↗
PubMed1989

Effect of screening and treatment on imported intestinal parasite infections: results from a randomized, controlled trial.

A randomized, controlled trial was undertaken to evaluate the effects of a screening program for intestinal parasite infection in newly arrived Southeast Asian refugees to Montréal, Québec, Canada, during 1982-1983. Families assigned to the screened groups were examined, infected persons were treated and followed until they were infection-free, and all screened families were reexamined at six months. Families assigned to the control groups were examined at six months only. Statistically significant prevalence differences in unadjusted and adjusted estimates over the six-month study period were found between screened persons and controls for each of three groups of refugees from Kampuchea, Laos, and Vietnam, respectively. In general, the greatest prevalence differences ascribed to the screening program were observed in hookworm and Ascaris lumbricoides infections. Continued high levels of Giardia lamblia and Strongyloides stercoralis infection were observed at six months; this raises concerns over the effective therapeutic management of infected persons, the risk of local transmission, and the relevance of screening for intestinal parasites in new arrivals from endemic areas.

Asia, Southeastern↗
PubMed1989

Absence of significant differences in intestinal parasite prevalence estimates after examination of either one or two stool specimens.

The authors undertook a retrospective search of intestinal parasite laboratory records obtained from 200 consecutive-day pairs of stool specimens to compare prevalence estimates from the first and second stool examinations. The laboratory results had previously been recorded as part of a screening program offered to Southeast Asian refugees arriving in Montréal, Québec, Canada, between July 1982 and February 1983. No statistically significant differences in either overall prevalences or parasite-specific prevalences were observed. This suggests that, at least in some population-based situations, single stool examinations provide estimates of intestinal parasite prevalence which are as valid as those from the routine examination of two consecutive-day specimens. Blinded studies must be undertaken to accurately assess the true value of multiple specimen submission in epidemiologic studies.

Asia, Southeastern↗
PubMed1989

Disaccharidase activity in the small intestine of gerbils (Meriones unguiculatus) during primary and challenge infections with Giardia lamblia.

The sequence of changes in the activity of six disaccharidases in the small intestine of gerbils during primary and secondary G lamblia infections was examined. The primary G lamblia infection induced a transient reduction in disaccharidase activity which was related to the highest trophozoite burden in the small intestine. During the primary exposure, a 30% to 85% decrease in the activity of enzymes was observed on days 10 and 20 after infection. Secondary exposure of gerbils to G lamblia caused a sharp decrease in disaccharidase activity as early as 24 h after challenge. The reduction in the enzyme activity was not influenced by the size of the challenge inoculum and occurred even when there were no live trophozoites in the small intestine. Disaccharidase deficiency could also be induced by challenge with the soluble extract of the trophozoites. Multiple challenge administrations of G lamblia trophozoites to gerbils induced a persistent disaccharidase deficiency. The results indicate that disaccharidase deficiency associated with the primary G lamblia infection probably represents a direct effect of the parasite on the brush border of the small intestine. On the other hand, the observed disaccharidase deficiency in the secondary G lamblia infection appears to be induced by the local immune responses of the host.

Animals↗