PubMed Health⌕ Search

Biomedical subjects

H V Wyatt

Publications and source records attributed to H V Wyatt.

At least 19 recordsLinked to original sources
PubMed1979

Poliomyelitis in the fetus and the newborn. A comment on the new understanding of the pathogenesis.

A survey of the literature shows that although poliovirus may be recovered from fetuses whose mothers have paralytic poliomyelitis, there is no evidence that the fetuses themselves are affected. It is suggested that if postnatal poliomyelitis results from an autoallergic response not developed in the fetus, then poliovirus cannot enter the CNS of the fetus. When a mother has paralytic poliomyelitis at delivery the neonate has a 40 per cent chance of poliomyelitis, with a case fatality rate of about 50 per cent. It is suggested that most of these neonates become infected by virus entry into the exposed olfactory and nasal nerve endings after the membranes have burst. This would explain the very short incubation period and the high case and case fatality rates.

Female↗
PubMed1978

Abortive poliomyelitis or minor illness as a clue to genetic susceptibility.

The model of genetic susceptibility to poliomyelitis has been used to examine minor illness caused by poliovirus infection. It is suggested that persons who are genetically susceptible but who have not converted to phenotypic susceptibility are those who develop minor illness. The overall rates of the sum of paralytic and minor illness are close to the predicted 26%. For families with a case of illness, the prediction that 58%--71% of the children become ill has been examined. The rates of illness in children of different ages in the same families should be similar. Data from a number of epidemics is shown to be consistent with the predictions of the model.

Adolescent↗
PubMed1978

Genetic susceptibility to wild and vaccine polio virus: genotypes and their frequency.

The frequency of proposed genotypes which predispose to poliomyelitis, is tabled. Susceptibility is due to a gene or linkage group of genes with a frequency of 2% for the homozygote and 24% for the heterozygote. Two subgroups are identified where a second gene might make the persons susceptible to vaccine strains of virus. Cutter vaccinees might form a third group with increased susceptibility under special circumstances. The age at which genetic susceptibility changes to phenotypic susceptibility may be modified by physical factors such as those due to congenital syphilis and Salvarsan, and thalidomide.

Adult↗
PubMed1978

Polio immunization: benefits and risks.

There are epidemiological as well as legal risks to polio immunization. The physician should compare the risks of vaccination with the risks which attend nonvaccination. Another view of the incidence of paralysis following oral poliovaccine (OPV) shows that the risk is about 1.6 cases per 10(6) nonimmune children given OPV and that this rises to about ten cases per 10(6) nonimmune adults exposed to OPV. There is little evidence of reversion to virulence of the virus and it is proposed that susceptibility of vaccinees and contacts to OPV is genetic. The risk of contracting poliomyelitis from either vaccine or wild virus rises about tenfold from the age of about three years to about ten years and thereafter remains constant. The risk of vaccinating children must be balanced against a tenfold risk of vaccinating when older and against a very much higher risk of paralysis or death from a wild virus. Present vaccination policies have virtually eliminated wild virus from the United States but have left many nonimmunes. The consequences of reintroduction of wild virus are examined, and the legal implications of genetic susceptibility are briefly discussed.

Disease Outbreaks↗
PubMed1977

Investigating an epidemic: a seven-part simulation used in teaching.

A seven-part exercise is described, based on published accounts of a school epidemic. Students have to complete each part before receiving the next: cumulative mistakes are therefore avoided. Analysis over four years shows consistent patterns of student responses. Details of statistical tests of the data are given.

Child↗
PubMedDate not supplied

Poliomyelitis in developing countries: lower limb paralysis and injections.

The distribution of muscle paralysis due to poliomyelitis is different in temperate and tropical countries. In temperate countries, 49% of children with paralysis were affected only in the legs compared with 85% in developing countries, 79% and 89% respectively had affected legs with other paralysis. This suggests that correction for lameness surveys is unnecessary. Muscles frequently injected and those with adjacent motor neurone tracts in the central nervous system were much more frequently affected in Nigerian than in UK children, whereas paralysis in other muscles was less frequent than in the UK children. This and other evidence points to a major causal role for injections in the high prevalence of polio in developing countries. Proof may however be impossible to obtain because less than 0.5% of all injections are followed by paralysis. There may also be damage to motor neurones, without paralysis, which may lead to later disabilities. Injections should be given to young children only when absolutely necessary.

Adolescent↗
PubMedDate not supplied

Unnecessary injections and paralytic poliomyelitis in India.

The effect of prior injections on the pattern and severity of paralytic poliomyelitis has been examined by a retrospective analysis of case notes from an outpatient pediatric clinic in South India. Of 262 children with acute polio, 176 had received unnecessary injections < 48 h before paralysis and 12 had received diphtheria-pertussis-tetanus or provocative injections. Two children injected in the right arm had paralysis in that limb only. Children with no injections (controls) had an equal chance of paralysis (0.73) in each left and right leg. Children with injections in the right or left gluteus or in both had a 19% greater chance of paralysis in the injected leg(s), whereas uninjected legs had a 31% lower chance of paralysis. Injected leg muscles were weaker than those of control children. Legs of control children were stronger than those with one leg injected and much stronger than those with both injected. More than 96% of the children had at least one leg paralysed. Age and vaccine status did not affect the results of injections. After injections there was greater likelihood of death or lack of recovery of muscle strength. About three-quarters of the children had received unnecessary injections; of these 60% had more severe paralysis and a non-paralytic attack became paralytic in 40%. If oral medicines for fevers and diarrhoea replaced unnecessary injections, the prevalence and severity of paralytic polio would be reduced.

Arm↗