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Biomedical subjects

M Szczeniowski

Publications and source records attributed to M Szczeniowski.

13 recordsLinked to original sources

Ebola hemorrhagic fever: lessons from Kikwit, Democratic Republic of the Congo.

The outbreak of Ebola hemorrhagic fever in Kikwit, Democratic Republic of the Congo, clearly signaled an end to the days when physicians and researchers could work in relative obscurity on problems of international importance, and it provided many lessons to the international public health and scientific communities. In particular, the outbreak signaled a need for stronger infectious disease surveillance and control worldwide, for improved international preparedness to provide support when similar outbreaks occur, and for accommodating the needs of the press in providing valid information. A need for more broad-based international health regulations and electronic information systems within the World Health Organization also became evident, as did the realization that there are new and more diverse partners able to rapidly respond to international outbreaks. Finally, a need for continued and coordinated Ebola research was identified, especially as concerns development of simple and valid diagnostic tests, better patient management procedures, and identification of the natural reservoir.

Democratic Republic of the Congo↗

Re-emergence of monkeypox in Africa: a review of the past six years.

Human monkeypox was first identified in 1970 in the Democratic Republic of the Congo. Extensive studies of this zoonotic infection in the 1970s and 1980s indicated a largely sporadic disease with a minority of cases resulting from person-to-person transmission, rarely beyond two generations. In August 1996, an unusually large outbreak of human monkeypox was reported, and cases continued through 1997 with peak incidence in August 1996, March 1997 and August 1997. Preliminary results from the field investigations in 1997 suggest a new epidemiological pattern where a majority of secondary cases result from person-to-person transmission, and a clinically milder disease. But there is preliminary laboratory evidence of a simultaneous outbreak of varicella in the same geographic region which will undoubtedly modify these preliminary results. Since smallpox was eradicated and vaccinia vaccination terminated in this region, the population of susceptible individuals has grown. The use of vaccination to protect the population at risk, however, must take into account HIV prevalence and the risk of generalized vaccinia when using vaccinia vaccine in populations where HIV is known to be present.

Africa↗

Human monkeypox in Kasai Oriental, Zaire (1996-1997).

Monkeypox is an orthopoxvirus with enzootic circulation in the rainforests of central and western Africa; the virus can be transmitted to humans and cause a syndrome clinically similar to smallpox (e.g., pustular rash, fever, respiratory symptoms, and in

Journal Article↗

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↗

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↗

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↗

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↗

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↗

Monkeypox virus in relation to the ecological features surrounding human settlements in Bumba zone, Zaire.

Since monkeypox virus was discovered in animals in 1958 and in man in 1971, several efforts have been made to identify the reservoir of the virus in nature. In July 1985 a study on human environments and animals suspected to maintain virus transmission was carried out in northern Zaire. The study revealed three well demarcated areas: the human settlement area, the agricultural area and the primary tropical rain forest. The first two were found inhabited by terrestrial and arboreal rodents and bats, while the larger animals have abandoned them. Data on human morbidity collected in the preceding years suggested that most of the patients were infected either in the settlement or in the agricultural area. Isolation of the virus from a squirrel confirmed this suggestion and proved, on the other hand, that the virus could circulate in an area deprived of the larger wild animals, including primates. The virus isolation and results of serologic testing suggest that out of three groups of animals inhabiting the agricultural area, the squirrels Funisciurus anerythrus should be considered a priority candidate to sustain virus transmission.

Adolescent↗

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↗

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↗

[Contagiousness of monkey pox for humans: results of an investigation of 2 outbreaks of the infection in Zaire].

The results of the investigation of two outbreaks of group monkeypox infection among humans (altogether 8 cases) in the zone of Bumba, Equatorial Province, Zaire, are presented. The primary source of infection in both outbreaks was not established, the outbreaks were supposedly caused by sick wild animals. Almost all persons affected by this infection were children aged 7 months to 7 years, never vaccinated against smallpox; the only exception was a 29-year old female patient, formerly vaccinated and revaccinated against smallpox. During one of the outbreaks the laboratory-confirmed transmission of infection from man to man was established in two generations. During the other outbreak there were grounds to suspect the transmission of infection in three generations, though the possibility of contacting infection from animals could not be completely ruled out. The existence of the inapparent form of monkeypox in humans was revealed.

Adult↗