PubMed Health⌕ Search

Biomedical subjects

D M MCLEAN

Publications and source records attributed to D M MCLEAN.

At least 19 recordsLinked to original sources
PubMed1965

ENTEROVIRAL SYNDROMES IN TORONTO, 1964.

Virological or serological investigations of 72 children in Toronto and environs, who were hospitalized between January and October 1964 with a variety of syndromes, revealed evidence of enteroviral infection in 29 subjects. Coxsackie B2 was the dominant enterovirus, being isolated from feces and/or cerebrospinal fluid (CSF) of three children with aseptic meningitis, three with pleurodynia, one with myalgia and one with pericarditis; four additional patients showed rising antibody titres to this virus. Coxsackie B1 virus, which has not been isolated in Toronto since 1950, was recovered from feces of three patients with pleurodynia, CSF of one patient with myalgia, and peritoneal fluid of a child with primary peritonitis; one patient with pericarditis showed a rising antibody titre to Coxsackie B1 virus. Coxsackie B3, B4 and Echo 23 viruses were associated with one case each of pleurodynia. Coxsackie B5 virus infected five patients with aseptic meningitis, and one each with pericarditis and myocarditis.

Canada↗
PubMed1964

POWASSAN VIRUS: SUMMER INFECTION CYCLE, 1964.

Between May 1, and September 15, 1964, neutralizing antibody to Powassan virus was detected in sera from 163 of 464 forest mammals captured in the Powassan-North Bay area of northern Ontario. These included 159 of 358 groundhogs and four of 43 red squirrels. Acquisition of antibody by juvenile groundhogs occurred principally during July and August. Powassan virus strains were isolated from tick pools containing two to 15 Ixodes cookei per pool which were removed from eight of 91 groundhogs in three townships during May, July and August. Virus was also recovered from blood of two groundhogs during May. Powassan virus was re-isolated from five of six tick pools and two blood clots by inoculation of swine kidney tissue cultures. These findings strongly suggest that during 1964 Powassan virus was maintained in nature by a cycle involving groundhogs and I. cookei ticks.

Animals↗
PubMed1964

ENTEROVIRAL AND MUMPS MENINGITIS IN TORONTO, 1963.

Virological investigations of 115 children with the aseptic meningitis syndrome during 1963 resulted in the isolation of enteroviruses from cerebrospinal fluid (CSF) and/or feces of 21 of 48 children who had no association with mumps. For the third successive year, Echo 9 was the dominant enterovirus in cases of aseptic meningitis in Toronto children, but no rashes were associated with Echo 9 meningitis during 1963, in contradistinction to previous years. Mumps virus was isolated from CSF of 25 patients by inoculation of rhesus monkey kidney cultures, and rising or elevated mumps antihemagglutinin titres in paired sera from a further 33 cases provided laboratory evidence of infection with mumps virus in 58 of 67 patients with mumps meningoencephalitis. No enlargement of salivary glands was noted in 20 laboratory-proved cases of mumps meningoencephalitis. Enteroviral meningitis occurred principally during summer, but the peak of mumps meningoencephalitis occurred during late winter.

Adolescent↗
PubMed1964

POWASSAN VIRUS: MORPHOLOGY AND CYTOPATHOLOGY.

Powassan virus, a North American tickborne group B arbovirus, multiplied after simultaneous inoculation into bottles or tubes of virus and trypsinized suspension of continuous-line cultures of rhesus monkey kidney cells, strain LLC-MK2. Cytopathic effects comprising cell rounding and cytoplasmic vacuolation were first observed five days after inoculation. Mixture of Powassan antiserum with virus before inoculation into tissue cultures inhibited the appearance of cytopathic effects. Hemagglutinins for rooster erythrocytes, optimally at pH 6.4 and 22 degrees C., first appeared in tissue culture supernatant fluids four days after inoculation.Electron microscopic observation of thin sections of infected tissue culture cells showed virus particles 360-380 A.U. along outer cell membranes and edges of cytoplasmic vacuoles. In phosphotungstic acid negatively stained preparations, intact virus particles, 400-450 A.U. total diameter, were observed inside infected cells. In particles in which the peripheral layer became discontinuous, geometrically arranged subunits compatible with cubic symmetry were observed.

Animals↗
PubMed1964

MUMPS MENINGOENCEPHALITIS, TORONTO, 1963.

Between January and June 1963, 45 children were hospitalized with mumps meningoencephalitis. Of 39 patients with laboratory evidence of mumps infection, 24 had parotitis and 15 showed no salivary gland involvement. Cerebrospinal fluids from 18 of 40 patients yielded mumps virus by inoculation of rhesus monkey kidney cultures; 33 subjects, including 12 of the 18 virus excretors, showed rising or elevated levels of mumps antihemagglutinin during convalescence. Between May 1959 and June 1963, mumps virus was recovered from cerebrospinal fluids of 50 of 126 cases of mumps meningoencephalitis; virus isolation rates were highest during the peak incidence of mumps meningoencephalitis in winter and early spring.Mumps vaccine (inactivated) was administered to 34 parents with no history of mumps, shortly after their children developed mumps. Mumps occurred in three of 17 parents without prevaccination mumps antihemagglutinins, and in two others, but in none of 15 who had prevaccination antibodies.

Antibodies↗
PubMed1963

MYXOVIRUSES ASSOCIATED WITH ACUTE LARYNGOTRACHEOBRONCHITIS IN TORONTO, 1962-63.

Between November 1962 and March 1963, myxoviruses were isolated from 95 of 224 children (40.5%), most of whom were aged less than three years, who were admitted to The Hospital for Sick Children, Toronto, with acute laryngotracheobronchitis (tracheitis or croup). Viral isolates included 87 strains of Parainfluenza-1, five of Parainfluenza-3, and three of Influenza A2. An epidemic of Influenza A2 afflicted Toronto during March 1963, at which time this virus was isolated from tracheitis patients.Myxoviruses were isolated from nasopharyngeal secretions of 285 of 794 tracheitis patients between November 1960 and March 1963. Parainfluenza-1 virus was the dominant serotype, being found in 241 (30.0%) of subjects. Three peaks of Parainfluenza-1 virus isolations were observed in December 1960, March 1962 and November 1962, and this serotype has been isolated during all months except June and July. Although most of the 28 Parainfluenza-3 virus infections occurred between November and February, this strain has also been isolated during summer. Strains of Influenza A2 and Influenza B viruses have been isolated from tracheitis patients during epidemics of influenza in Toronto due to these agents.

Antibodies↗
PubMed1963

Enterovirus infections in Toronto during 1962.

Of 37 children from Toronto and surrounding districts who developed aseptic meningitis during summer 1962, 17 excreted Echo 9 virus in feces and/or cerebrospinal fluid, 12 of whom showed rising or elevated Echo 9 antibody levels in paired sera. A further two patients yielded Echo 14 virus from cerebrospinal fluid, one of whose feces also contained this virus, and both patients showed rising Echo 14 antibody titres. Morbilliform rashes without rhinitis or conjunctivitis were encountered in three Echo 9 excretors who had aseptic meningitis and in six patients without meningitis, three of whom yielded Echo 9 virus.Paralytic poliomyelitis was encountered in three patients, all of whom excreted polioviruses which showed aluminum marker characteristics of virulent strains. One Type III patient presented with twitching and left-sided hemiparesis.Febrile reactions accompanied by headache or other symptoms were observed in seven children who ingested Sabin trivalent poliovirus vaccine one to 17 days previously. All made complete clinical recoveries. Polioviruses with aluminum or temperature markers typical of attenuated vaccine strains were isolated from feces of all patients, including Type III from five patients, Type I from three patients and Type II from one patient.

Child↗
PubMed1963

Powassan and Silverwater viruses: ecology of two Ontario arboviruses.

Powassan virus was isolated from a pool of Ixodes marxi ticks collected during late August 1962, from a red squirrel, Tamiasciurus hudsonicus, and from blood obtained from a red squirrel during early October 1962 near Powassan, Ontario, where a child contracted fatal encephalitis due to this virus in September 1958. The frequent detection of Powassan virus neutralizing antibody in sera of squirrels captured during autumn, but rarely at other seasons, and the frequent I. marxi infestation of squirrels, some of which contain antibody, but the lack of occurrence of I. marxi on other forest rodents, suggest that I. marxi ticks are vectors and squirrels are reservoirs of Powassan virus infection. Isolation of Silverwater virus from Haemaphysalis leporis-palustris ticks which infested a snowshoe hare Lepus americanus near Powassan demonstrates the presence of this agent in the Powassan area also.

Animals↗
PubMed1962

Smallpox in Toronto, 1962.

A 14-year-old boy was seen on August 17, 1962, with a vesicular eruption of five days' duration. The vesicles were about 0.5 cm. in diameter, loculated, mainly distributed centrifugally, and all were at the same stage of development. On August 8, he left his residence in a rural area of southern Brazil where alastrim is endemic. His last smallpox vaccination was received at least six years ago. Alastrim virus was isolated from vesicle fluid obtained on August 17 and 19 by inoculation of chorioallantoic membranes of embryonated eggs. A fourfold rising level of vaccinia antihemagglutinin in paired serum samples was consistent with infection by alastrim virus. The patient has since recovered uneventfully.

Brazil↗