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Biomedical subjects

J H Nakano

Publications and source records attributed to J H Nakano.

At least 19 recordsLinked to original sources
PubMed1987

Serological survey for human monkeypox infections in a selected population in Zaire.

About 3460 persons living in Kole zone of East Kasai, in Zaire, were examined and their sera screened initially by a haemagglutination-inhibition test. Of these, 667 (19%) were positive. Radioimmunoassay adsorption tests for the presence of monkeypox- or vaccinia-specific antibodies gave unequivocal results in 300 of these sera; the remaining 47 were nonspecific. Monkeypox-specific antibodies were found in sera of 27 individuals, of all ages and both sexes, giving an overall prevalence rate of monkeypox virus-specific antibodies of 0.8%. The prevalence rate was four times higher in the 5 to 9 year age group (1.3%) than in children aged 0 to 4 years (0.3%), and was highest (2.4%) in the 15 to 19 year age group. There was no significant difference in the prevalence rates between the sexes. As might be expected, there are substantially higher prevalence rates in persons living in forest galleries than in those in savannah, and among those living in areas where human monkeypox cases had occurred in the past compared with those living in other localities. Nineteen children whose sera showed specific monkeypox antibodies were re-examined. Twelve showed facial and body skin changes suggesting the presence of vesiculo-pustular disease in the past; four of these had been known registered monkeypox cases. Seven children had neither signs nor history of past vesiculo-pustular disease, suggesting that they had suffered from subclinical infection with monkeypox virus.

Antibodies, Viral↗
PubMed1986

Human monkeypox: a study of 2,510 contacts of 214 patients.

A study of 2,510 contacts of 214 patients with human monkeypox was conducted in Zaire from 1980 to 1984. Among the contacts of 130 primary cases of human monkeypox, a further 22 co-primary and 62 secondary cases were detected, and an additional fourteen people who had no evidence of clinical disease had positive serological results. A majority of the clinical and subclinical cases of monkeypox occurred in children less than 10 years of age. Immunity in vaccinated persons now appears to be waning because 16 overt cases occurred in contacts who had been vaccinated. The overall attack rate for contacts without a vaccination scar (7.2%) differed significantly from the attack rate for those who had been vaccinated in the past (0.9%). The attack rate for household contacts was significantly higher than that for other contacts, among both unvaccinated (four times higher) and vaccinated (seven times higher) household contacts. Many unvaccinated contacts living in the same household as the index case under conditions of maximum exposure, however, escaped not only the disease but also infection.

Adolescent↗
PubMed1986

Four generations of probable person-to-person transmission of human monkeypox.

This paper examines an outbreak of five cases of human monkeypox which occurred in children belonging to two families living in the West Kasai region of Zaire during May-July 1983. Epidemiologic investigations suggest that the first case was infected from an animal source, possibly a monkey, and that each of the other four cases was infected from a previous human case. Three of these cases of presumed person-to-person transmission occurred in close household contacts. The other case infection occurred either by casual contact within the hospital compound, or possibly because of infection due to use of the same syringe for injections. Human monkeypox is the most important orthopoxvirus infection in the post-smallpox eradication period. The disease is a zoonosis and person-to-person transmission is rather difficult. Thus, this episode is a rare event and special analysis of the circumstances is discussed. However, it supports the necessity to carry out surveillance and research on this disease as recently reported by Arita et al.

Animals↗
PubMed1985

Can variola-like viruses be derived from monkeypox virus? An investigation based on DNA mapping.

The results are presented of a special study to determine whether variola-like "whitepox" viruses could arise as white pock variants of monkeypox virus after one or a few mutations. DNA mapping by cross-hybridization of restriction endonuclease DNA fragments was carried out on 18 orthopoxviruses relevant to this study, including variola and monkeypox viruses and white (non-haemorrhagic) pock producers recovered from chorioallantoic membranes infected with red (haemorrhagic) pock-producing monkeypox viruses. The distinctiveness of the DNA maps of true variola and monkeypox viruses indicated that spontaneous production of "whitepox" from monkeypox virus was genetically impossible. These and other observations led to the conclusion that the "whitepox" viruses recovered from monkeypox virus stocks had an exogenous origin.

Animals↗
PubMed1983

Microtiter determination of measles hemagglutination inhibition antibody with filter papers.

Epidemiological studies of measles and measles immunization frequently require determination of measles antibody status. In developing countries, where venipuncture is frequently unacceptable and where refrigerated storage of serum specimens is often unavailable, microtiter techniques not requiring refrigeration are required. We developed a filter paper technique that measures measles hemagglutination inhibition antibody and meets these criteria. Comparison of separately collected venous blood and peripheral blood collected on filter paper demonstrated 97% agreement in terms of presence or absence of antibody. In 30 of 32 measles specimens, 94% of titers were the same or varied by less than 2 twofold dilutions.

Antibodies, Viral↗
PubMed1982

Further field testing of the more heat-stable measles vaccines in Cameroon.

Two of the more heat-stable measles vaccines were field tested in Cameroon. Both maintained the minimum required infectivity titre and the ability to induce seroconversion after storage unreconstituted at 37 degrees C for 14 days. One of the vaccines, studied after reconstitution, maintained its ability to induce seroconversion after reconstitution and storage at 25 degrees C for 48 hours and at 37 degrees C for at least four hours. The increased heat stability of the studied vaccines will not eliminate the need for a well-monitored system of vaccine conservation and distribution but will ease the rigid cold-storage requirements of conventional measles vaccines.

Antibodies, Viral↗
PubMed1981

Multiple genetic changes can occur in the oral poliovaccines upon replication in humans.

Poliovirus isolates of serotypes 2 and 3 from patients whose paralytic poliomyelitis cases were classified as oral vaccine-associated were analysed by oligonucleotide mapping of the virus genomes and by polyacrylamide gel electrophoresis of the virus proteins. Oligonucleotide maps of all isolates were similar to the maps of the corresponding oral vaccine strain. No two isolates gave identical maps. Most maps differed from that of the vaccine strain by at least one oligonucleotide spot. Maps of some isolates revealed numerous differences, indicating that multiple (greater than 100) genetic changes had occurred in the vaccine virus genomes during replication in one or two individuals. In contrast, maps of some neural tissue isolates showed minimal differences from the reference vaccine maps, raising the possibility that neurovirulence may be restored by a small number of genetic changes. For many isolates, changes were also detected in the mobilities of processing rates of the virus proteins.

Adult↗
PubMed1981

Immunofluorescence staining for detection of variola virus.

In September 1975 Bangladesh was the only country in the world with endemic variola major, and the eradication of the disease was imminent. A rapid and accurate laboratory diagnostic method was required to supplement immunodiffusion in agar gel and culture on chorioallantoic membrane of embryonated egg available at the Institute of Public Health in Dacca, Bangladesh. To determine its effectiveness, a new, improved immunofluorescence (IF) staining technique was introduced. Laboratory specimens (scabs or vesicular or pustular impressions) were collected from patients who had, or were suspected of having, smallpox. Seventy-eight of 144 specimens collected were found to be IF positive for smallpox. As the number of laboratory-positive cases far exceeded the number of clinically diagnosed smallpox cases, IF-positive cases were reinvestigated and subsamples of the IF-positive specimens were tested at a World Health Organization poxvirus reference laboratory at the Centers for Disease Control in Atlanta, Ga. The results indicated 100% sensitivity for the IF technique (no false-negative results) in diagnosing variola major but also showed a high rate of false-positive results. Consequently, IF could not be recommended as a routine screening test for smallpox.

Animals↗
PubMed1981

Characterization of antibodies to orthopoxviruses in human sera by radioimmunoassay.

Serological surveillance of suspected orthopoxvirus infections in man is important for confirming the success of the worldwide smallpox eradication programme. An adsorption radioimmunoassay (RIA) was used to differentiate sera from patients who were naturally infected with human monkeypox or variola virus, and individuals who were immunized with vaccinia virus. The antisera were adsorbed with uninfected chicken chorioallantoic membrane (CAM) and vaccinia-infected CAM before reacting in RIA with vaccinia, monkeypox, and variola antigens. Each serum group showed characteristic patterns of residual antibody activity which made it possible to identify antibody specificities.When 45 human sera were tested by this method, 71% were identified as having vaccinia, variola, or monkeypox adsorption characteristics, while the remaining 29% could not be identified. Of the identified sera, 9 were characteristic of vaccinia, 8 of variola, and 15 of monkeypox. Six of the 15 monkeypox sera were virologically confirmed monkeypox infections, 6 were suspected monkeypox infections but were not virologically confirmed, and 3 were of unknown aetiology.The adsorption RIA provides a method of identifying serologically the poxvirus responsible for infection long after the acute phase of illness.

Animals↗
PubMed1981

Occupationally-acquired smallpox in an IgM-deficient health worker.

A 21-year-old Indian who worked as a vaccinator in the smallpox programme developed an atypical case of variola major despite several previous, successful vaccinations. The clinical course of the disease was unusual, as there were two distinctly separate "crops" of smallpox. The disease began less than one month after a successful vaccination, which therefore gave the briefest period of protection recorded for this reliable immunization. The patient was found to have a virtually complete IgM deficiency with normal levels of circulating antibody against orthopox virus.

Adult↗
PubMed1980

A study of the specificities of sequential antisera to variola and monkeypox viruses by radioimmunoassay.

The specificities of antisera during development of the humoral antibody response to poxvirus antigens were examined in monkeys injected with chimp-9 whitepox virus or monkeypox virus. Sera were obtained from 3 African green (vervet) monkeys inoculated with chimp-9 whitepox virus, 1 rhesus monkey inoculated with monkeypox virus, and 2 rhesus monkeys inoculated with soluble monkeypox viral antigen. The sequentially obtained sera from each animal were adsorbed with uninfected chicken chorioallantoic membranes (CAM) or vaccinia virus-infected CAM. The adsorbed sera were tested by radioimmunoassay to determine the specificity of the residual antibodies to vaccinia, variola, and monkeypox viruses. The adsorbed sera at different stages of the immune response showed increasing specificity with time after inoculation. Generally, antibodies in sera collected earlier than 21-27 days after immunization could not be identified after adsorption, but late sera could be identified unequivocally.

Epitopes↗
PubMed1978

Naturally acquired measles immunity in Nepal and Sri Lanka.

Serological surveys of naturally acquired measles antibodies in children 6--72 months of age were done in Nepal and Sri Lanka. The prevalences of naturally acquired measles immunity are compared by age groups with serological studies done in other countries. Suggestions are made regarding age ranges for measles vaccination programs.

Humans↗
PubMed1977

Serological relatedness of monkeypox, variola, and vaccinia viruses.

Closely related human and monkey orthopoxviruses were differentiated by serologic techniques. Antiviral sera were tested by immunodiffusion for reactivity against six different viral antigens prepared from either infected cell cultures or infected chorioallantoic membranes (CAMs) of embryonated eggs. Portions of each antiserum were separately absorbed with heterologous antigens from infected CAMs to remove common reactivity. The absorbed sera formed immunodiffusion precipitates with both types of antigen preparation and revealed specific-character differences that made it possible to classify the viruses as variola, vaccinia, or monkeypox. Cross-complement fixation tests were also used to examine the immunologic reactivities of antisera to detergent-treated, purified preparations of three orthopoxviruses. Only common reactivities were detected by this method, however, and differentiating reactivities were not observed.

Complement Fixation Tests↗