Biomedical subjects
A O Carter
Publications and source records attributed to A O Carter.
The effectiveness of a prenatal education programme for the prevention of congenital toxoplasmosis.
A 10 min education programme was developed which, if effective in changing the behaviour of pregnant women, would eliminate or greatly reduce the risk of congenital toxoplasmosis. It was taught in 26 randomly selected (case) prenatal classes offered to women early in their pregnancy. The remaining 26 (control) classes received routine class material which did not mention toxoplasmosis. A questionnaire was administered to all women prior to this early class (pre-test) and again after the last prenatal class, held just prior to delivery (post-test). Changes in pet, food and personal hygiene behaviour between the pre- and post-test were determined and a score calculated by adding points for change towards those behaviours recommended in the programme and subtracting points for change in the opposite direction. Cat owners in case classes had a significantly higher score in pet hygiene behaviour than those in control classes (P less than 0.05). No significant difference was found between the food or personal hygiene scores of women in case and control classes, possibly because of low power. However, although behaviours did not differ on the pre-test, women in case classes had significantly better cooking methods for roast beef and hamburger on the post-test (P less than 0.05 and P less than 0.01 respectively). It is concluded that this programme is effective and should be offered to all women in order to reduce congenital toxoplasmosis incidence.
Epidemiologic study of deaths and injuries due to tornadoes.
A case-control study, using both matched and unmatched controls, was carried out on individuals who were injured or killed by a series of tornadoes that passed through Ontario, Canada, on May 31, 1985. Many serious injuries (25%) and almost all (83%) deaths were the result of becoming airborne, while most minor injuries (94%) were due to being struck by objects. Head injury was the most common injury type. Few (21%) of those in buildings chose the recommended location, and most (61%) were not in the least damaged part. Most (91%) had less than one minute's warning, and only 47% had a functioning radio at the time the tornado hit. The following risk factors for injury and death were identified: poor building anchorage; location other than in a basement, especially outdoors; age over 70 years; and high wind strength. These findings support previous findings and point to measures which have potential for preventing death or serious injury in future tornadoes: adequate warning systems and public education to ensure that individuals understand the warning and respond by seeking appropriate shelter. Those in adequately anchored buildings should shelter in an interior room or basement. Those who are outdoors, in poorly anchored buildings, mobile homes, or portable classrooms require access to an adequately anchored building, preferably with a basement, during severe storm warnings. This should be arranged by local authorities.
A severe outbreak of Escherichia coli O157:H7--associated hemorrhagic colitis in a nursing home.
In September 1985, an outbreak of Escherichia coli O157:H7 enteritis affected 55 of 169 residents and 18 of 137 staff members at a nursing home. The outbreak was characterized by two phases: a primary wave whose source was probably a contaminated sandwich meal and a secondary wave compatible with person-to-person transmission of infection. Among the elderly residents, the incubation period was 4 to 9 days (mean, 5.7 +/- 1.2). Older age and previous gastrectomy increased the risk of acquiring the infection (P = 0.01 and 0.03, respectively). Antibiotic therapy during exposure was associated with acquiring a secondary infection (P = 0.001). Hemolytic uremic syndrome developed in 12 affected residents (22 percent), 11 of whom died. Overall, 19 (35 percent) of the affected residents died, 17 (31 percent) from causes attributable to their infection. Antibiotic therapy after the onset of symptoms was associated with a higher case fatality rate in the more severe cases, possibly because patients with more severe disease tended to be treated with antibiotics. There were no complications or deaths among the affected members of the staff. Evidence of infection by verotoxin-producing E. coli O157:H7 was detected in 30 of 70 cases on the basis of isolation of this organism or demonstration of free verotoxin in stools. All isolates belonged to the same phage type. The high morbidity and mortality associated with this condition emphasize the need for proper food hygiene, rapid identification of outbreaks of disease, and prompt institution of infection-control techniques among the institutionalized elderly.
Congenital toxoplasmosis: epidemiologic features and control.
Toxoplasmosis is caused by the parasite Toxoplasma gondii. It is acquired from undercooked meat or from food or fomites contaminated by cat feces. The disease can be transmitted to the fetus only during maternal parasitemia, which is associated with primary infection. Extrapolation from current data suggests that there are 140 to 1400 cases of congenital toxoplasmosis per year in Canada and that 70 to 280 of the infants are severely affected at birth; many of the others suffer sequelae later in life. Serologic diagnosis of primary infection in the mother is quite sensitive and specific. Diagnosis in the infant is more difficult and may take several months. Prenatal treatment of the woman and postnatal treatment of the infant are hampered by the lack of proven efficacy as well as ethical and compliance problems. Preventive serologic screening and prophylaxis have the same drawbacks. Educating young women to avoid infection is an inexpensive, low-risk intervention that would be the preferred preventive strategy if it could be shown to be effective. Immunization may prove to be the most cost-effective method of preventing congenital toxoplasmosis if a safe and effective vaccine is developed.
First aid treatment of electric shock.
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Electric current flow through human skin at power frequency voltages.
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Effects of power frequency voltages on amputated human limb.
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Bone density estimates and risk factors for osteoporosis in young women.
The bone mineral density (BMD) of the calcaneus was estimated in 185 young women from the United Arab Emirates, using SAHARA ultrasound. All participants completed a questionnaire on factors potentially associated with osteoporosis. In all, 29 (15.7%) of the women were classified as having osteopenia and none as having osteoporosis. Participants with osteopenia were more likely to have had a later onset of menarche, irregular periods, lower body mass index, and a positive family history of osteoporosis. Only late menarche and low body mass index, however, were independent predictors of osteopenia.
Eradication of indigenous poliomyelitis in Canada: impact of immunization strategies.
During the period 1950-1954, surveillance for paralytic poliomyelitis in Canada revealed an average of 1,914 cases (13.2 cases per 100,000) annually. The licensing and widespread use of inactivated poliovirus vaccine (IPV) in 1955 coincided with a marked decline in disease rates. Due to incomplete vaccine coverage of the population, a resurgence began in 1958 and peaked in 1959, despite an observed vaccine efficacy of 96% for 3 doses of IPV. The introduction and widespread use of oral poliovirus vaccine (OPV) started in 1960 and coincided with a decline in disease rates. Virtual elimination of the natural disease was achieved in the 1970s in all provinces regardless of the specific immunization program chosen (IPV or OPV alone or combined). From 1965 to 1988, 51 cases of paralytic poliomyelitis were reported in Canada. Thirty-five of these cases, all but one occurring before 1980, were attributed to wild virus infection, (14 caused by imported virus and 21 assumed to be endemic). Sixteen cases were OPV-associated: 4 in vaccine recipients and 12 in contacts of OPV recipients. Vaccine-associated paralysis in recipients and contacts occurred at the rate of one case per 9.5 million and 3.2 million vaccine doses distributed, respectively. The risk of paralysis attributable to OPV therefore is small compared to the overall benefit of the vaccine. Both IPV and OPV appear equally effective, and theoretically, a combination of the two (IPV followed by OPV) provides the best risk benefit ratio. Occasional exposure of the Canadian population to imported wild virus requires that high levels of population immunity be maintained.
Estimation of vaccine coverage in Ontario children.
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