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Biomedical subjects

Z Jezek

Publications and source records attributed to Z Jezek.

At least 19 recordsLinked to original sources
PubMed2001

[Ebola fever: an emerging disease].

One of the most fatal diseases encountered by mankind so far is Ebola fever. Ebola fever is caused by a highly pathogenic virus from the Filoviridae family which is found in nature in four different sub-types which differ among others also by their pathogenicity for man. The hitherto detected EBO sub-types are stable do not change in the course of an epidemic nor in the course of the patient's illness, nor during passage of the virus from one subject to another. The author presents a historical review of epidemics, nosocomial and laboratory infections, spread and epizoonosis caused by the Ebola virus. The author presents a detailed clinical picture describing the frequency and evolution of different clinical symptoms and signs based on the observation of 103 patients infected with the Ebola virus in Kikwit, Zaire (nowadays Democratic Republic of Congo) in 1995. In the laboratory diagnosis individual tests are mentioned assessing the presence of the virus, viral antigens and antibodies, incl. the most recent immunohistochemical test. The author mentions the problem of patient care and his therapy, incl. available antiviral drugs and passive immunotherapy. He also discusses the possibility and probability of spread of the Ebola virus into our environment. He mentions principles for transport of subjects with suspected disease, demands for their strict isolation and maximum protection of the attending staff incl. barrier nursing technique. The author discusses also principles of epidemiological work, detection and isolation of sources, identification and follow up of contacts and epidemiological supervision of affected areas. Past epidemics made it possible to assemble many scientific findings and practical experience. These make it possible to cope nowadays with any attack of the Ebola virus not only in areas of its epizootic occurrence.

Diagnosis, Differential↗
PubMed2000

[20 years without smallpox].

It is 20 years since the 33rd World Health Assembly (WHA) declared that "worldwide eradication of smallpox" was achieved. This was the outcome of many years intensive work of the World Health Organization (WHO) and its member countries. In 1958 the WHA adopted the recommendation that WHO should initiate the eradication of smallpox on a worldwide scale. In 1967 the eradication activities in hitherto endemic countries became more intense. Smallpox affected 31 countries and 15 countries recorded from occasional cases. Every year more than 10 million people contracted the disease and two million of them died. A ten-year limit for the eradication was set. Gradually smallpox were eradicated in South America, then in Asia and last in Africa where the last case of endemic smallpox was recorded in 1977 in Somalia. WHO ensured international collaboration, close coordination of activities and mobilization of financial, personal and material resources. It ensured also that tested methods were fully applied in the affected countries regardless of their political, religious and cultural differences. In the eradication activities participated hundreds of thousands of local and 700 health professionals from abroad, incl. 20 Czechoslovak epidemiologists. The worldwide costs of eradication amounted to some 300 million dollars, i.e. some 23 million per year. The most important contribution of the eradication of smallpox was in addition to the termination of human suffering, worldwide financial savings estimated to 1-2 billion US dollars per year. These saved personal and financial resources could be used for other important health projects. The eradication of variola was defined as eradication of clinical forms of smallpox not as the final eradication of the variola virus. The importance of laboratories keeping the variola virus increased steeply at the time when clinical cases of smallpox were eradicated. From the beginning of the eighties WHO made an effort to reduce their number to a minimum. Since 1984 strains of variola are officially kept only in two centres collaborating with WHO. The Organization suggested destruction of the kept viruses in 1987, i.e. ten years after the eradication of smallpox. Unfortunately some political and scientific circles did not agree with this intention. Even recommendations to destroy the virus in 1993 and again in 1999 were not accepted. In the nineties fear of bio-terrorism and secret modernization of biological weapons influenced some member countries to change their opinion on the intended destruction of the virus. Despite this in May 1999 the WHA adopted a resolution that the final destruction of all variola strains is the objective of all member countries of WHO and recommended to postpone the destruction of the virus to the year 2002. The reason for postponement is current research of new antiviral preparations and better vaccines. There is again hope that all that will be left of the variola virus will be magnetic signals on computer diskettes.

Bioterrorism↗
PubMed2000

[Bioterrorism--a public and health threat].

In recent years the fear of bioterrorism, of secret modernization and dissemination of biological weapons is increasing. Facts detected recently in Iran, Japan and the former Soviet Union provide evidence that there are countries and dissident groups which have access to modern technology of cultivation of dangerous pathogens as well as motivation for their use in acts of terrorism or war. The menace of biological terrorism is nowadays, as compared with the past, much greater. The most feared candidates as regards production of biological weapons are the pathogens of smallpox, anthrax and plague. The author discusses the serious character of possible events associated with terrorist dissemination of these pathogens. It is much esier to produce and use biological weapons than to create effective systems of defence against them. The menace of bioterrorism and bioweapons must not be exaggerated nor underestimated. The possible terrorist use of bioweapons is real. At present even the most advanced industrial countries cannot quarantee effective protection of their populations. Fortunately they are however aware of their present vulnerability. Our society is not equipped to cope with bioterrorism. Preparation and reinforcement of the health services, in particular of sections specialized in the control of infectious diseases is an effective step to divert the sequelae and suffering associated with terrorist use of biological agents. It is essential to be prepared. This calls for time and funds which unfortunately are not plentiful.

Anthrax↗
PubMed1999

Ebola between outbreaks: intensified Ebola hemorrhagic fever surveillance in the Democratic Republic of the Congo, 1981-1985.

Surveillance for Ebola hemorrhagic fever was conducted in the Democratic Republic of the Congo from 1981 to 1985 to estimate the incidence of human infection. Persons who met the criteria of one of three different case definitions were clinically evaluated, and blood was obtained for antibody confirmation by IFA. Contacts of each case and 4 age- and sex-matched controls were also clinically examined and tested for immunofluorescent antibody. Twenty-one cases of Ebola infection (persons with an antibody titer of > or = 1:64, or lower if they fit the clinical case definition) were identified, with a maximum 1-year incidence of 9 and a case fatality rate of 43%. Cases occurred throughout the year, but most (48%) occurred early in the rainy season. Fifteen percent of contacts had antibody titers > or =1:64 to Ebola virus, compared with 1% of controls (P < .0001). Results suggest that Ebola virus periodically emerges from nature to infect humans, that person-to-person transmission is relatively limited, and that amplification to large epidemics is unusual.

Adolescent↗
PubMed1993

Risk factors for HIV infection among abandoned Romanian children.

OBJECTIVE: To determine risk factors for HIV infection among abandoned Romanian infants and children living in a public institution. METHODS: A cross-sectional study was conducted in June 1990 among 101 children between 0 and 4 years of age living in an orphanage. Orphanage and hospital records were reviewed and a blood specimen for hepatitis B and HIV serologic testing obtained from each child. A case-control study was conducted using data from the cross-sectional study. Cases were HIV-positive children; one HIV-negative control, matched by age, was selected for each case. RESULTS: Overall, 20 (20%) children were HIV-positive, 88 (87%) tested positive for antibody to hepatitis B core antigen, and 32 (32%) were hepatitis B surface antigen-positive. In the case-control study, HIV-positive children had received more therapeutic injections [mean, 280; median, 231] than age-matched HIV-negative children [mean; 142, median, 155; P = 0.02]. Cases were more likely than controls to have received over 200 lifetime injections (odds ratio, 5.7; 95% confidence interval, 1.2-32.7). Blood transfusions and mother-to-child transmission were excluded as routes of HIV transmission. By reviewing sterilization records and interviewing local health-care workers, we determined that needles and syringes were often re-used without proper disinfection in the orphanage. CONCLUSIONS: These data provide strong epidemiologic evidence that indiscriminate injections with contaminated needles and syringes were responsible for HIV transmission in this population.

Blood Transfusion↗
PubMed1991

Acquired immunodeficiency syndrome in Romania.

After the initial description of acquired immunodeficiency syndrome (AIDS) in Romania in late 1989, national AIDS case surveillance was established with a modified version of the World Health Organisation (WHO) clinical case definition. This modified case definition requires that AIDS cases have both clinical and serological evidence of human immunodeficiency virus (HIV) infection. Before December, 1989, Romania had reported 13 AIDS cases to WHO. By Dec 31, 1990, 1168 AIDS cases were reported to Romania's Ministry of Health, of which 1094 (93.7%) occurred in children less than 13 years of age at diagnosis. Of these, 1086 (99.3%) were in infants and children less than 4 years of age, and 683 (62.4%) in abandoned children living in public institutions at the time of diagnosis. By Dec 31, 1990, 493 (45.1%) mothers of children with AIDS had been located and tested, and 37 (7.5%) were positive for HIV; 423 (38.7%) cases were in children who had received transfusions of unscreened blood, and 6 (0.5%) were in children with clotting disorders. HIV transmission through the improper use of needles and syringes is strongly suspected in most of the remaining 628 (57.4%) children with AIDS, most of whom had received multiple therapeutic injections. This outbreak demonstrates the serious potential for HIV transmission in medical facilities that intensively and improperly use parenteral therapy and have poor sterilisation technique.

Acquired Immunodeficiency Syndrome↗
PubMed1988

The transmission potential of monkeypox virus in human populations.

Data on monkeypox in Zaire over the five years 1980-1984 are analysed to assess the protection imparted by past smallpox vaccination and the transmission potential of the virus in unvaccinated communities. Attack rates in individuals with and without vaccination scars indicated that smallpox vaccination (discontinued in 1980) imparted approximately 85% protection against monkeypox. It is predicted that monkeypox virus will continue to be introduced into human communities from animal sources, and that the average magnitude and duration of monkeypox epidemics will increase as vaccine-derived protection declines in the population. On the other hand, current evidence indicates that the virus is appreciably less transmissible than was smallpox, and that it will not persist in human communities, even in the total absence of vaccination. The findings thus support the recommendation of the Global Commission for the Certification of Smallpox Eradication to cease routine smallpox vaccination in monkeypox endemic areas, but to encourage continued epidemiological surveillance.

Democratic Republic of the Congo↗
PubMed1988

Human monkeypox: disease pattern, incidence and attack rates in a rural area of northern Zaire.

Human monkeypox is a zoonosis that occurs sporadically in the tropical rainforest of western and central Africa. This article presents the results of epidemiological features of 91 monkeypox patients reported in Bumba zone in northern Zaire during the period 1981 to 1985. Their age ranged from 7 months to 29 years (93% below 15 years of age). 11% of patients had visible smallpox vaccination scars. Deaths occurred sporadically; the overall case-fatality rate was 9%. 91 patients arose in 61 separate outbreaks; 42 of them consisted of only a single case. The source of infection was suspected to be animal for 70 cases, and human for the remaining 21 cases. The illness occurred in all months of the year. There was a considerable clustering of cases in the northern part of the zone. The average annual incidence rate in the observed zone was 0.63 cases per 10,000 population with marked differences in age, time and place. The average annual primary attack rate among unvaccinated individuals (1.7/10,000) sharply contrasted with those vaccinated (0.04/10,000). The secondary attack rate for contacts without vaccination scar (4.3%) differed significantly from those who had been vaccinated in past (0.7%). Many unvaccinated contacts living under conditions of maximal exposure to index cases escaped not only the disease but also infection. The low incidence rate of human monkeypox indicates its limited public health importance even in a well-known enzootic area.

Adolescent↗
PubMed1988

Clinico-epidemiological features of monkeypox patients with an animal or human source of infection.

Clinical and laboratory examinations were carried out on a total of 338 monkeypox patients in Zaire from 1981 to 1986. An animal source of infection was suspected in 245 (72%) and interhuman transmission for the remaining 93 patients. Among those whose infection was presumably acquired from an animal source, the most affected groups were children aged 3-4 years (27%) and 5-6 years (20%), while only 4% of cases were over 15 years old; there was a considerable preponderance of males (58%) over females (42%), especially in the age group 5-14 years. Among those presumably infected by person-to-person transmission, the age distribution was more uniform, adult patients tending to be relatively more common, and there were more females (57%) than males (43%).Based on comparisons of the frequency and intensity of clinical signs and symptoms among patients infected from an animal source and those who were infected by another patient, there was no evidence that the disease becomes more severe and the transmitted virus more virulent or more easily transmissible from person to person after one or more passages through human hosts.

Adolescent↗
PubMed1988

Human monkeypox: secondary attack rates.

Data on human monkeypox collected in Zaire during the six years 1981-86 were analysed to assess the extent of interhuman transmission of monkeypox virus. Among the 2278 persons who had close contact with 245 monkeypox patients infected from an animal source, 93 fell ill and were presumed to have been infected from the known human source: 69 of these were spread in the first generation, 19 in the second generation, and the remaining five cases in the third and fourth generation.The secondary attack rates were correlated with the age, sex, place of residence, and vaccination status of the contacts. There was an overall 3% probability of becoming ill following infection from a known human source. The affected household was the main focal point for interhuman transmission of monkeypox virus. The highest attack rate (11.7%) occurred among unvaccinated household contacts in the age group 0-4 years. However, the majority of susceptible persons who had been close to patients in the confined space of poorly ventilated huts failed to develop illness. There was no evidence of an increase in the secondary attack rate between 1970-80 and 1981-86.The inefficient spread from person to person, even in conditions of maximum exposure, supports the concept that monkeypox virus is poorly adapted for sustained transmission between humans and that such transmission does not pose a significant health problem.

Adolescent↗
PubMed1988

[Human monkey pox: its clinico-epidemiological characteristics].

During the course of the smallpox eradication programme, a new eruptive disease clinically resembling smallpox was discovered in Zaire. The disease, which was named monkeypox after the virus, is a zoonosis occurring sporadically in countries of western and central Africa with tropical rain forest. The studies carried out in Zaire from 1980 through 1985 showed that monkeypox affects mainly children in relatively small remote villages whose population has traditionally frequent contacts with wild animals. Apart from the wildlife, the virus can be transmitted from man to man, but among other sources of infection sick persons did not exceed 20%. Presumed human transmission has occurred in 38 out of 61 outbreaks of human monkeypox and only once reached the third and once the fourth generation; the transmission in all affected villages under observation has extinguished itself. Considering the sporadic and relatively rare occurrence of the disease and expected complications following the immunization with vaccinia which protects from monkeypox, introduction of mass vaccination in the areas at risk is hardly justified at present.

Africa, Central↗
PubMed1988

Monkeypox virus: ecology and public health significance.

Recent investigations have revealed that monkeypox virus infections occur with a high prevalence in several species of squirrels belonging to the genus Funisciurus, less frequently in squirrels of the genus Heliosciurus, and rarely in forest-dwelling primates. These squirrels commonly inhabit the secondary forests around human settlements in the rural areas of Zaire, especially where oil palms are grown, and are rare in the primary rain forest.Human infection with monkeypox virus occurs most frequently in the 5-9-year-old age group, particularly in small villages where the children hunt and eat squirrels and other small mammals. As the populations are now increasing in number and can no longer feed on wild life alone for their animal protein requirements, the development of animal husbandry as a source of meat will certainly decrease the risk and the incidence of human monkeypox, even in areas where monkeypox virus is present in the local population of squirrels.Although population growth and economic development in western and central Africa will probably reduce the risk of human infection with monkeypox virus, visitors to these areas who are likely to come into contact with wild animals should be offered smallpox vaccination as a protection.

Animals↗
PubMed1988

Human monkeypox: confusion with chickenpox.

Human monkeypox is a zoonosis occurring sporadically in the tropical rain forest of western and central Africa. The exact incidence and geographical distribution are unknown, since many cases are not recognized. Special surveillance was established in three regions in Zaire in 1981 that led to a substantial increase in reported cases. The question arose as to the possibility that clinical diagnostic errors cause some cases of monkeypox to be misdiagnosed as other eruptive diseases. This paper presents the results of a study assessing the extent of and reasons for these clinical diagnostic errors in areas where health staff as well as the general public are aware of human monkeypox. In Zaire in the period 1981-1986, 977 persons with skin eruption not clinically diagnosed as human monkeypox were laboratory tested. 3.3% of human monkeypox cases were found among 730 patients diagnosed as cases of chickenpox, 7.3% among cases diagnosed as "atypical chickenpox" and 6.1% among cases with skin rash for which clinical diagnosis could not be established. The diagnostic difficulties were mainly based on clinical features characteristic of chickenpox: regional pleomorphism (in 46% of misdiagnosed cases), indefinite body-distribution of skin eruptions (49%), and centripetal distribution of skin lesions (17%). Lymph-node enlargement was observed in 76% of misdiagnosed patients. In the absence of smallpox, the main clinical diagnostic problem is the differentiation of human monkeypox from chickenpox. The presence of lymphadenopathy, pre-eruptive fever and slower maturation of skin lesions are the most important clinical signs supporting correct diagnosis of monkeypox.

Adolescent↗
PubMed1987

Human monkeypox: clinical features of 282 patients.

We present the clinical features and course of 282 patients with human monkeypox in Zaire during 1980-1985. The ages of the patients ranged from one month to 69 years; 90% were less than 15 years of age. The clinical picture was similar to that of the ordinary and modified forms of smallpox. Lymphadenopathy, occurring in the early stage of the illness, was the most important sign differentiating human monkeypox from smallpox and chickenpox. The symptoms, signs, and the course of the disease in patients who had been vaccinated against smallpox differed significantly from those in unvaccinated subjects. Pleomorphism and "cropping" similar to that in chickenpox occurred in 31% of vaccinated and 18% of unvaccinated patients. The prognosis depended largely on the presence of severe complications. No deaths occurred among vaccinated patients. In unvaccinated patients the crude case-fatality rate was 11% but was higher among the youngest children (15%).

Adolescent↗
PubMed1987

Stochastic model for interhuman spread of monkeypox.

With the eradication of smallpox, systematic routine vaccination with vaccinia has ceased and an increasing proportion of the human population in tropical rain forest areas of central and western Africa lacks vaccinia-derived immunity to monkeypox virus. This raises the question of the ability of monkeypox virus to establish and maintain itself in an unvaccinated population through continuous man-to-man transmission. A computerized stochastic model of Monte Carlo type was constructed to assess this potential risk. Simulated series were repeated 100 times to obtain distributions of predicted outcomes for decreasing levels of vaccination coverage (70 per cent, 50 per cent, and 0 per cent). The results revealed a substantial increase in new secondary cases in the total absence of vaccinia-induced immunity. Nevertheless, none of the simulated series did lead to an "explosive" epidemic. The model clearly indicated diminishing numbers of cases in successive generations and eventual cessation of transmission. Therefore, it appears highly improbable that the virus could maintain itself permanently in communities by interhuman transmission. After the eradication of smallpox, human monkeypox constitutes the most important orthopoxvirus infection in man, but analysis of information collected up to this time suggests that it does not represent currently a serious public health problem or a challenge to the achieved eradication of smallpox.

Adolescent↗
PubMed1987

The role of squirrels in sustaining monkeypox virus transmission.

When the research on the ecology of monkeypox virus entered the latest stage in 1984, three groups of animals were considered priority candidates for maintenance of virus circulations in nature because of their relatively higher population density: terrestrial rodents, squirrels, and gregarious bats. Following the isolation of the virus from a wild squirrel in 1985 another survey was carried out in Bumba zone of Zaïre in January-February 1986, which included collection of animal samples, later on tested by WHO collaborating laboratories. No antibodies were found in 233 rodents tested. A high prevalence of monkeypox-specific antibodies (24.7%) found in 320 squirrels of Funisciurus anerythrus species suggested that these animals sustain virus transmission in the areas surrounding human settlements. A consistently high level of antibody prevalence found among squirrels Heliosciurus rufobrachium suggested that this species is also steadily involved in the transmission. The squirrels, the only mammals frequently infected by monkeypox in the areas of human activities, which are frequently trapped by the population, are obviously a major source of infection for human beings. Out of 39 primates collected during the survey from the primary forest, three were found seropositive for monkeypox. At the moment, however, it is difficult to say whether the primates play an important role in sustaining virus transmission in nature, or (like human beings) that they are an occasional host of the virus. Possibilities are discussed of monkeypox virus transmission being sustained by squirrels outside the areas of major human activities.

Animals↗