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Biomedical subjects

W H Mosley

Publications and source records attributed to W H Mosley.

67 records · Page 4Linked to original sources
PubMed1968

Serological studies in cholera. 2. The vibriocidal antibody response of cholera patients determined by a microtechnique.

A microtechnique is described for the determination of vibriocidal antibodies to Vibrio cholerae, using 0.025 ml of fingertip blood or venous serum per test. This test could be used in epidemiological surveys, or as a routine test on patients admitted to hospital.Fourfold or greater rises in vibriocidal titre were noted for 96.5% of 370 bacteriologically confirmed cholera patients in an endemic area of East Pakistan (91.5% for the 94 children under 5 years in the study group). It is necessary to test sera against both Ogawa and Inaba serotypes of V. cholerae, as a significant titre rise was found against the homologous serotype only in 11% of the cases, and against the heterologous serotype only in 2%.Six serologically positive but bacteriologically negative persons were found to be household contacts of confirmed cholera patients (and 3 of the contacts had been vaccinated against cholera within 1 week before testing); 3 other cases (1.6%) were considered to be false positives.The vibriocidal test using fingertip blood was compared with daily rectal swabbing for the detection of cholera carriers among 153 household contacts of cholera patients, who had not received cholera vaccine within 2 weeks before testing; 16% gave a positive vibriocidal titre, while V. cholerae was isolated from 13% only.

Adolescent↗
PubMed1968

Serological studies in cholera. 3. Serum toxin neutralization--rise in titre in response to infection with Vibrio cholerae, and the level in the "normal" population of East Pakistan.

A method has been evaluated for the titration of antibodies to Vibrio cholerae, based on the ability of sera containing such antibodies to neutralize the inflammatory effect of a factor from V. cholerae cultures on the skin of test animals.Ninefold or greater rises in toxin-neutralization titre were found in 73% of 111 bacteriologically confirmed cholera patients in an endemic area of East Pakistan, and in 2.5% of bacteriologically negative patients. This method compares well with the microtechniques developed for the titration of vibrio-agglutinating and vibriocidal antibodies to V. cholerae.The toxin-neutralization method has the advantage that no titre rise is produced in response to vaccination with the whole-cell vaccine in current use in East Pakistan.Relatively high toxin-neutralization titres were noted among children under 15 years of age without vibriocidal or agglutinating antibodies, and without a history of prior infection with V. cholerae.

Adolescent↗
PubMed1968

A serological survey for cholear antibodies in rural east Pakistan. 1. The distribution of antibody in the control population of a cholera-vaccine field-trial area and the relation of antibody titre to the pattern of endemic cholera.

Controlled cholera vaccine field trials were held in Matlab Bazar in rural East Pakistan in 1963 and 1964. In July-September 1965, a serological survey for cholera antibodies was carried out on a random sample of the field-trial population. Results are given for the control group only, as representative of the pattern found in an endemic cholera area. Only 2% of the blood samples from children under 10 years of age were found to have detectable agglutinating antibody (titres of 1:20 or more), while the proportion in the age-group over 30 years was 27%-30%. Tests for vibriocidal antibody showed that none of the blood samples from children under 1 year of age contained detectable antibody, while 87%-90% of those from adults over 30 years did so. The rise in the geometric mean vibriocidal titre showed an almost linear correlation with a sharp fall in the cholera case rate with age. Since a similar survey in a non-endemic area (Czechoslovakia) did not reveal any rise in antibody titre with age, and since cholera epidemics in areas without recent experience of the disease are characterized by a higher incidence rate in adults than in children, it is suggested that the antibody titres give a measure of the level of immunity in a population.

Adolescent↗
PubMed1968

Cholera vaccine field trials in east Pakistan. 2. Effectiveness in the field.

A cholera-vaccine field trial in a rural area of East Pakistan where cholera is highly endemic has indicated that a high-potency whole-cell vaccine can provide significant protection against disease due to Vibrio cholerae for at least 18 months. This vaccine gave more than 70% protection during the first cholera season after vaccination. In the second cholera season after the administration of a single dose of vaccine, protection fell in those under 5 years of age, while continuing at significantly effective levels in older persons.Purified Ogawa antigen (lipopolysaccharide) afforded significant protection to adults against disease due to the heterologous Inaba serotype, but only protected children against milder diarrhoeas.The effect of cholera vaccine on the incidence of infections among family contacts of cholera patients was variable. Vaccine had no effect on the proportion of asymptomatic infections.Diarrhoeal disease associated with V. cholerae occurred predominantly among children, while protection was most marked among adults. Adverse reactions were practically restricted to the adults, suggesting that children will not only tolerate a larger dose, but actually require a larger dose for maximum protection against infection.

Adolescent↗
PubMed1968

A serological survey for cholera antibodies in rural east Pakistan. 2. A comparison of antibody titres in the innunized and control populationd of a cholera-vaccine field-trial area and the relation of antibody titre to cholera case rate.

Controlled field trials of a highly antigenic cholera vaccine were held in Matlab Bazar in rural East Pakistan in 1963 and again in 1964. In July-September 1965, a serological survey for cholera antibodies was carried out on a random sample of the field-trial population. This survey revealed that it was possible to demonstrate the effect of a single injection of the cholera vaccine per head on the proportion of the population with detectable vibriocidal and agglutinating antibody 10 and 22 months after injection. More significantly, the reduction in cholera case rate caused by the vaccine could be correlated with the rise in vibriocidal antibody after vaccination, suggesting that the serological response to vaccine in man may be a useful measure of vaccine potency. The survey also indicated that in this endemic cholera area, with a high level of immunity in adults, a single injection of cholera vaccine was in fact a booster dose for the majority of the population. Thus, the results of cholera vaccine field trials in endemic areas cannot be directly extrapolated to predict the effects of the same vaccine in non-endemic areas.

Adolescent↗
PubMed1968

The relationship of vibriocidal antibody titre to susceptibility to cholera in family contacts of cholera patients.

A bacteriological and serological study of family contacts of 81 cholera patients was carried out in Dacca, East Pakistan. In the 10-day follow-up, 78 (16.7%) of 466 contacts were found to be infected with Vibrio cholerae; half of them were symptomatic and 29 had to be admitted to hospital. A study of serum pairs revealed a 4-fold, or greater, rise in titre in 86% of those infected in whom diarrhoea was present, and in 77% of individuals with inapparent infections. The infection rate fell markedly with age. Serological tests for vibriocidal antibody on blood specimens collected at the initiation of the follow-up revealed higher titres with increasing age. Vibrio cholerae infection, whether symptomatic or asymptomatic, predominantly occurred in individuals with low titres.

Adolescent↗
PubMed1965

Studies of cholera El Tor in the Philippines. I. Characteristics of cholera El Tor in Negros Occidental Province, November 1961 to September 1962.

After freedom from cholera for over a quarter of a century, the Philippines in 1961 experienced an epidemic of cholera. The disease, shown to be caused by the El Tor strain of cholera vibrio, was clinically indistinguishable from classical Asian cholera. Studies were undertaken in Negros Occidental Province from August to October 1962 to characterize various aspects of the epidemics in this province. This paper describes the general characteristics of the epidemics in Negros Occidental from November 1961 through September 1962.Two types of epidemic occurred. The first, explosive in nature, suggested a common source of spread of infection; the second, with a more protracted course, seemed to be due to person-to-person spread of disease. In the second epidemic, a single hospitalized case in a household and a single hospitalized case in a community were the most common findings, suggesting that infection did not spread easily or, if easily spread, caused significant disease on rare occasions only.

Adolescent↗
PubMed1965

Studies of cholera El Tor in the Philippines. 2. A retrospective investigation of an explosive outbreak in Bacolod City and Talisay, November 1961.

The introduction of cholera into many of the islands of the Philippines in 1961 often occurred in an explosive manner. The disease was introduced into Bacolod City and Talisay in Negros Occidental Province in such a manner in November 1961. The authors describe the results of an analysis of hospital and health department records in Bacolod City and Talisay and the results of interviews conducted with adult patients 10 months after the explosive outbreak.The results suggest that infection during the initial explosive wave of cases in Bacolod City and Talisay in November 1961 was transmitted principally by shrimp that were consumed raw.

Adolescent↗
PubMed1965

Studies of cholera El Tor in the Philippines. 3. Transmission of infection among household contacts of cholera patients.

As part of a broad epidemiological investigation of cholera El Tor in the Philippines, the authors cultured rectal swabs obtained from the household contacts of cholera patients hospitalized in the Negros Occidental Provincial Hospital from August through October 1962. Additional infected persons were found in 25 (60%) of the 42 households with confirmed cases and in 55 (18%) of 302 household contacts of confirmed patients. Since only five of the 55 infected household contacts developed illness severe enough to require hospitalization, it was apparent that those with severe illness accounted for but a small proportion of the total infections. Asymptomatic infections were rarely found outside the households with proven cases, suggesting that close person-to-person contact was necessary for the spread of infection. Asymptomatic carriers as well as symptomatic patients appeared to play significant roles in the transmission of infection.

Adolescent↗
PubMed1965

Studies of cholera El Tor in the Philippines. 4. Transmission of infection among neighbourhood and community contacts of cholera patients.

As part of a broad study on the epidemiology of cholera El Tor in the Philippines, the authors conducted bacteriological surveys among the community contacts of suspect cholera patients hospitalized in the Negros Occidental Provincial Hospital from August through October 1962. Fourteen (2%) of 698 community contacts of persons with confirmed cholera patients were found on initial culture to be infected.Intensive studies in two communities suggested that infection was spread primarily by close personal contact; in a third community, contamined well-water presumably served as a vehicle for the transmission of infection. Diagnosed and undiagnosed cases, undiagnosed cholera deaths and asymptomatic infections all played a role in cholera transmission.The studies tend to confirm that the second or recurrent epidemic in Negros Occidental was primarily caused by person-to-person spread. Although the seemingly isolated or sporadic cases were sometimes associated with a more general distribution of the cholera vibrio, the cholera infections invariably were highly localized among close contacts even within densely populated areas with poor sanitation.

Adult↗