A collection of 2,209 isolates of six polysaccharide capsule types of Haemophi/us influenzoe, including 1,975 serotype b isolates recovered in 30 countries was characterized for electrophoretically demonstrable allele profiles at 17 metabolic enzyme loci. Two hundred eighty distinct multilocus genotypes were distinguished, and cluster analysis revealed two primary phylogenetic divisions. The population structure of encapsulated H. influenzae is clonal. Currently, most of the invasive disease worldwide is caused by serotype b strains of nine clones, Strains producing serotype c, e, and f capsules belong to single divisions and have no close genetic relationships to strains of other serotypes, Serotype a and b strains occur in both primary phylogenetic divisions, probably as a result of transfer and recombination of serotype-specific sequences of the cap region between clonal lineages. A close genetic relatedness between serotype d isolates and some strains of serotypes a and b was identified, There are strong patterns of geographic variation, on an intercontinental scale, in both the extent of genetic diversity and the clonal composition of populations of encapsulated strains, The analysis suggests that the present distribution of clones is, in part, related to patterns of racial or ethnic differentiation and historical demographic movements of the human host populations.
Pulsed-field gel electrophoresis and gene typing were able to differentiate among 3,597
Bordetella pertussis
isolates circulating in Alberta and Québec Provinces, Canada, from 1985 to 1994 and distinguish them from the strains used in vaccine production. This study provides a baseline for continued surveillance of prevalent and emerging strains of
B. pertussis
in Canada.
We describe a case of severe tuberculous pancreatitis in a 26-year-old woman with miliary tuberculosis. Recognition of this complication is important as it may interfere with adequate absorption of anti-tuberculous drugs and it can lead to unnecessary laparotomy.
Eight cases of neurocysticercosis were encountered at the two major neurological centers affiliated with McGill University in Montreal in 4 years. All patients were immigrants who had been in Canada for a period of 1 to 18 years and came from South America (three cases), Haiti (three cases), and Greece (two cases). Five patients had parenchymal cysts and presented with epilepsy; three had the racemose form and presented with hydrocephalus. Four patients with parenchymal cysts were treated by removal of the cysticercus and did well. One patient with numerous cysts was treated with praziquantel with good clinical and radiological results. Two patients with the racemose form were treated by cyst aspiration, cerebrospinal fluid (CSF) diversion, and praziquantel and did well. Another patient with the racemose form, seen before the advent of praziquantel, died of cysticercosis infection. Neurocysticercosis is not uncommon in the immigrant population of large North American cities. Single symptomatic cysts can be evacuated surgically with good results; multiple parenchymatous cysts can be treated with praziquantel. Patients with the racemose form who are treated with CSF diversion and praziquantel do well, although those who are only treated surgically die of their disease.
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