Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “monkeypox”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed2005

Experimental infection of prairie dogs with monkeypox virus.

Studies of experimental infection of prairie dogs (Cynomys ludovicianus) with monkeypox virus are described. After intraperitoneal infection, all of the animals died within 11 days. Virus was cultured from their blood and oropharynx several days before death; at necropsy, most of the organs tested contained monkeypox virus. Marked hepatic and splenic necrosis were observed, along with mild inflammatory changes in the lungs. After intranasal (IN) infection, the primary pathologic changes were in the lungs and pleural cavity. Some of the IN infected animals (40%) survived, and monkeypox virus could be cultured from their nasal discharge and oropharynx for <22 days. Ulcerative lesions also developed on the lips, tongue, and buccal mucosa of the surviving animals. Our findings support an earlier report, which suggested that infected prairie dogs can transmit monkeypox virus by respiratory and mucocutaneous contact with susceptible animals and persons.

Animals↗
PubMed2006

Monkeypox: an epidemiologic and clinical comparison of African and US disease.

Monkeypox is a double-stranded DNA virus and a member of the genus Orthopoxvirus. Human monkeypox was first identified in the Democratic Republic of the Congo (formerly Zaire) in 1970. The first outbreak in the western hemisphere occurred in the spring of 2003. Important epidemiologic and clinical differences exist between human monkeypox in the United States and in Africa, including sex distribution, case fatality, morphology of skin lesions, and associated lymphadenopathy. These divergent clinical presentations could be caused by mode of transmission (skin inoculation vs ingestion), the skin color of affected patients, the training backgrounds of those who saw and documented disease outbreaks, the virulence of monkeypox strains involved, nutritional status, access to advanced medical care, and the prevalence of prior smallpox vaccinations.

Africa↗
PubMed2004

Extensive lesions of monkeypox in a prairie dog (Cynomys sp).

Monkeypox with extensive lesions was diagnosed in a prairie dog that was involved in a recent human outbreak of monkeypox in the Midwestern United States. Gross lesions included oral ulcers, pulmonary consolidation, enlarged cervical and thoracic lymph nodes, and multifocal, small, white umbilicated plaques in the gastrointestinal wall. Microscopic lesions were extensive in the lungs and consisted of fibrinonecrotic bronchopneumonia with vasculitis and poorly defined eosinophilic intracytoplasmic inclusion bodies in cells thought to be alveolar epithelial cells, histiocytes, and fibroblasts. Multifocal necrotizing lesions, often accompanied by myxedema, were also present in most of the other examined organs. Aggregates of pox viral particles were observed within lesions by transmission electron microscopy. Monkeypox virus infection was confirmed by real-time polymerase chain reaction and virus culture at the Centers for Disease Control and Prevention. This report highlights the difficulties of rapid diagnosis of exotic or emerging diseases and further substantiates the prairie dog as an animal model of monkeypox.

Animals↗
PubMed2006

Structure and regulatory profile of the monkeypox inhibitor of complement: comparison to homologs in vaccinia and variola and evidence for dimer formation.

The outbreak of monkeypox in the Unites States in the summer of 2003 was the first occurrence of this smallpox-like disease outside of Africa. This limited human epidemic resulted from cross-infection of prairie dogs by imported African rodents. Although there were no human fatalities, this outbreak illustrates that monkeypox is an emerging natural infection and a potential biological weapon. We characterized a virulence factor expressed by monkeypox (monkeypox inhibitor of complement enzymes or MOPICE). We also compared its structure and regulatory function to homologous complement regulatory proteins of variola (SPICE) and vaccinia (VCP). In multiple expression systems, 5-30% of MOPICE, SPICE, and VCP consisted of function-enhancing disulfide-linked homodimers. Mammalian cells infected with vaccinia virus also expressed VCP dimers. MOPICE bound human C3b/C4b intermediate to that of SPICE and VCP. Cofactor activity of MOPICE was similar to VCP, but both were approximately 100-fold less efficient than SPICE. SPICE and VCP, but not MOPICE, possessed decay-accelerating activity for the C3 and C5 convertases of the classical pathway. Additionally, all three regulators possessed heparin-binding capability. These studies demonstrate that MOPICE regulates human complement and suggest that dimerization is a prominent feature of these virulence factors. Thus, our data add novel information relative to the functional repertoire of these poxviral virulence factors. Furthermore, targeting and neutralizing these complement regulatory active sites via mAbs is a therapeutic approach that may enhance protection against smallpox.

Amino Acid Sequence↗
PubMed1985

Human monkeypox: a newly emerged orthopoxvirus zoonosis in the tropical rain forests of Africa.

During the course of the recently concluded smallpox eradication program, a new human orthopoxvirus infection was discovered which is caused by monkeypox virus. The disease occurs sporadically in remote villages within tropical rain forests of West and Central Africa. The disease is rare; only 155 cases having been reported from 1970 to 1983. The symptoms and signs of human monkeypox resemble those of smallpox, differing significantly only in the occurrence of lymphadenopathy with human monkeypox disease. Of 155 cases, some 80% are believed to have resulted from infection from an as yet unknown animal reservoir; the rest occurred among unvaccinated close contacts among whom a secondary attack rate of 15% was observed. Although person-to-person spread appears to have occurred in some instances, few cases were observed in the third or fourth generation of transmission and none thereafter. Since 1982, the incidence of human monkeypox infections in Zaire has increased concomitant with an intensified surveillance program. Additional reasons which might explain the increased incidence are discussed. Further surveillance and research of this primarily zoonotic infection are warranted and are in progress.

Adolescent↗
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↗
PubMed2004

The detection of monkeypox in humans in the Western Hemisphere.

BACKGROUND: During May and June 2003, an outbreak of febrile illness with vesiculopustular eruptions occurred among persons in the midwestern United States who had had contact with ill pet prairie dogs obtained through a common distributor. Zoonotic transmission of a bacterial or viral pathogen was suspected. METHODS: We reviewed medical records, conducted interviews and examinations, and collected blood and tissue samples for analysis from 11 patients and one prairie dog. Histopathological and electron-microscopical examinations, microbiologic cultures, and molecular assays were performed to identify the etiologic agent. RESULTS: The initial Wisconsin cases evaluated in this outbreak occurred in five males and six females ranging in age from 3 to 43 years. All patients reported having direct contact with ill prairie dogs before experiencing a febrile illness with skin eruptions. We found immunohistochemical or ultrastructural evidence of poxvirus infection in skin-lesion tissue from four patients. Monkeypox virus was recovered in cell cultures of seven samples from patients and from the prairie dog. The virus was identified by detection of monkeypox-specific DNA sequences in tissues or isolates from six patients and the prairie dog. Epidemiologic investigation suggested that the prairie dogs had been exposed to at least one species of rodent recently imported into the United States from West Africa. CONCLUSIONS: Our investigation documents the isolation and identification of monkeypox virus from humans in the Western Hemisphere. Infection of humans was associated with direct contact with ill prairie dogs that were being kept or sold as pets.

Adolescent↗
PubMed2005

Monkeypox virus: histologic, immunohistochemical and electron-microscopic findings.

BACKGROUND: Human monkeypox, an emerging viral zoonosis first recognized in Africa, has recently emerged in the mid-western US. Initially, it presents with skin eruptions and fevers with diaphoresis and rigors. Clinically, the skin lesions progress from papules to vesiculopustules to resolving eschars. METHODS: Three cutaneous biopsy specimens from two patients with polymerase chain reaction (PCR)-proven monkeypox were available for review. The histologic, immunohistochemical and electron-microscopic features were identified. RESULTS: The clinical progression of lesions is mirrored histologically with ballooning degeneration of basal keratinocytes and spongiosis of a mildly acanthotic epidermis progressing to full thickness necrosis of a markedly acanthotic epidermis containing few viable keratinocytes. A lichenoid-mixed inflammatory cell infiltrate is present, which exhibits progressive exocytosis with the keratinocyte necrosis. Inflammation of the superficial and deep vascular plexes, eccrine units and follicles is also present. Viral cytopathic effect is manifest by multinucleated syncytial keratinocytes. Immunohistochemically, viral antigen is detected within keratinocytes of the lesional epidermis, follicular and eccrine epithelium and few dermal mononuclear cells. Electron microscopy reveals virions at various stages of assembly within the keratinocyte cytoplasm. CONCLUSIONS: The histologic differential diagnosis includes herpes simplex virus, varicella and other pox viruses, such as smallpox. The first one may be differentiated histologically, immunohistochemically and electron microscopically. The last two may be differentiated using PCR assay for the monkeypox extracellular-envelope virus protein gene.

Antigens, Viral↗
PubMed2006

Subunit recombinant vaccine protects against monkeypox.

The smallpox vaccine Dryvax, a live vaccinia virus (VACV), protects against smallpox and monkeypox, but is contraindicated in immunocompromised individuals. Because Abs to VACV mediate protection, a live virus vaccine could be substituted by a safe subunit protein-based vaccine able to induce a protective Ab response. We immunized rhesus macaques with plasmid DNA encoding the monkeypox orthologs of the VACV L1R, A27L, A33R, and B5R proteins by the intradermal and i.m. routes, either alone or in combination with the equivalent recombinant proteins produced in Escherichia coli. Animals that received only DNA failed to produce high titer Abs, developed innumerable skin lesions after challenge, and died in a manner similar to placebo controls. By contrast, the animals vaccinated with proteins developed moderate to severe disease (20-155 skin lesions) but survived. Importantly, those immunized with DNA and boosted with proteins had mild disease with 15 or fewer lesions that resolved within days. DNA/protein immunization elicited Th responses and binding Ab titers to all four proteins that correlated negatively with the total lesion number. The sera of the immunized macaques recognized a limited number of linear B cell epitopes that are highly conserved among orthopoxviruses. Their identification may guide future efforts to develop simpler, safer, and more effective vaccines for monkeypox and smallpox.

Amino Acid Sequence↗
PubMed1983

Human monkeypox transmitted by a chimpanzee in a tropical rain-forest area of Zaire.

A case of monkeypox infection in a six-month-old baby girl who had been bitten by a wild chimpanzee in Kivu, Zaire, was investigated. The child had not been exposed to any monkeypox-like disease and no cases of such disease had occurred in the surrounding area during previous months. The time of onset of rash was consistent with the virus having been transmitted from the chimpanzee. However, it is still not known whether chimpanzees and other primates or lower mammals are the primary reservoir of monkeypox infection.

Accidents, Home↗
PubMed1978

Differential inhibitory effects of 5-bromodeoxyuridine on vaccinia and monkeypox viruses.

Replication of vaccinia and monkeypox viruses was impeded in the presence of 5-bromodeoxyuridine (BUdR) in RL-33 cells derived from rabbit lung tissue. The different degree of inhibition was found among strains of those viruses, in which it was evident that five strains (CV-1, Lister, IHD, Dairen-I and Ikeda) of vaccinia viruses resulted in more reduced yields of infectious virus than four strains (Sen-19, Orang Utan, Copenhagen and Sierra Leone) of monkeypox viruses. There was also strain variation in BUdR sensitivity within vaccinia viruses but not in the case of monkeypox viruses.

Bromodeoxyuridine↗
PubMed2001

The pathology of experimental aerosolized monkeypox virus infection in cynomolgus monkeys (Macaca fascicularis).

Cynomolgus monkeys (Macaca fascicularis) were exposed by fine-particle aerosol to lethal doses of monkeypox virus, Zaire strain. Death, attributable to fibrinonecrotic bronchopneumonia, occurred 9 to 17 days postexposure. Lower airway epithelium served as the principal target for primary infection. The relative degree of involvement among lymphoid tissues suggested that tonsil, mediastinal, and mandibular lymph nodes were also infected early in the course of the disease, and may have served as additional, although subordinate, sites of primary replication. The distribution of lesions was consistent with lymphatogenous spread to the mediastinal lymph nodes and systemic dissemination of the virus through a monocytic cell-associated viremia. This resulted in lesions affecting other lymph nodes, the thymus, spleen, skin, oral mucosa, gastrointestinal tract, and reproductive system. The mononuclear phagocyte/dendritic cell system was the principal target within lymphoid tissues and may also have provided the means of entry into other systemic sites. Hepatic involvement was uncommon. Lesions at all affected sites were characterized morphologically as necrotizing. Terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining of select lesions suggested that cell death within lymphoid and epithelial tissues was due in large part to apoptosis. Skin and mucosal surfaces of the respiratory and gastrointestinal tracts also exhibited variable proliferation of epithelial cells and subjacent fibroblasts. Epithelial intracytoplasmic inclusion bodies, consistent with Guarnieri bodies, were usually inconspicuous by light microscopy, but when present, were most readily apparent in the stratified squamous epithelium of the oral mucosa and epidermis. Multinucleated syncytial cells were also occasionally observed in the stratified squamous epithelium of the tongue, tonsil, and skin, and in the intestinal mucosa. Monkeypox virus antigen was readily demonstrated by immunohistochemistry using anti-vaccinia mouse polyclonal antibodies as well as anti-monkeypox rabbit polyclonal antibodies. Detectable poxviral antigen was limited to sites exhibiting obvious morphologic involvement and was most prominent within epithelial cells, macrophages, dendritic cells, and fibroblasts of affected tissues. The presence of poxviral antigen, as determined by immunohistochemistry, correlated with ultrastructural identification of replicating virus. Concurrent bacterial septicemia, present in one monkey, was associated with increased dissemination of the virus to the liver, spleen, and bone marrow and resulted in a more rapidly fatal clinical course.

Aerosols↗
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↗
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↗
PubMed2002

Characterization of wild-type and cidofovir-resistant strains of camelpox, cowpox, monkeypox, and vaccinia viruses.

Cidofovir ([(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine] [HPMPC])-resistant forms of camelpox, cowpox, monkeypox, and vaccinia viruses were developed by prolonged passage in Vero 76 cells in the presence of drug. Eight- to 27-fold-higher concentrations of cidofovir were required to inhibit the resistant viruses than were needed to inhibit the wild-type (WT) viruses. Resistant viruses were characterized by determining their cross-resistance to other antiviral compounds, examining their different replication abilities in two cell lines, studying the biochemical basis of their drug resistance, and assessing the degrees of their virulence in mice. These viruses were cross resistant to cyclic HPMPC and, with the exception of vaccinia virus, to (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)adenine. Three of the four resistant cowpox and monkeypox viruses exhibited reduced abilities to infect and replicate in 3T3 cells compared to their abilities in Vero 76 cells. Compared to the WT virus polymers the resistant cowpox virus DNA polymerase was 8.5-fold less sensitive to inhibition by cidofovir diphosphate, the active form of the drug. Intracellular phosphorylation of [3H]cidofovir was not stimulated or inhibited by infection with resistant cowpox virus. In intranasally infected BALB/c mice, WT cowpox virus was 80-fold more virulent than the resistant virus. Cidofovir treatment (100 mg/kg of body weight, given one time only as early as 5 min after virus challenge) of a resistant cowpox virus infection could not protect mice from mortality. However, the drug prevented mortality in 80 to 100% of the mice treated with a single 100-mg/kg dose at 1, 2, 3, or 4 days after WT virus challenge. By application of these results to human orthopoxvirus infections, it is anticipated that resistant viruses may be untreatable with cidofovir but their virulence may be attenuated. Studies will need to be conducted with cidofovir-resistant monkeypox virus in monkeys to further support these hypotheses.

3T3 Cells↗
PubMedDate not supplied

[Generalized monkeypox in orally infected rabbits and white mice].

In the past 5 years 17 human cases of monkeypox with 4 deaths were reported in African countries. The source and the mechanism of transmission of the infection are unknown. One of the possible modes of human infection could be through monkey meat used for food. The paper presents the results of the study of susceptibility of 4 species of laboratory animals to monkeypox virus given orally. Adult rabbits, guinea pigs, and hamsters were found to be resistant. Ten-day-old rabbits and 8-, 10- and 12-day-old mice developed generalized infection with eruptions and high lethality. The infection was transmitted to uninfected rabbits of the same litter, apparently by air-borne droplet mode. The obtained model of generalized monkeypox infection after per os administration of the virus and the fact of air-borne droplet transmission of infection may serve as indirect evidence of the possibility of transmission of the infection by this mode in nature.

Animals↗
PubMed1976

Susceptibility of some rodent species to monkeypox virus, and course of the infection.

The authors studied the susceptibility of five species of rodent to monkeypox virus inoculated by various routes and the course of the infection. Reactions varied from complete resistance to lethal generalized infection with rash. Rabbits and white mice appeared to be the most susceptible species and young animals were more susceptible than adults. Monkeypox virus was found to infect young animals by natural routes, i.e., per os and intranasally. Transmission by contact occurred among 10-day-old rabbits. Since antibodies to monkeypox virus may persist for over a year in the sera of convalescent animals, serological examination of animals is recommended for studying the ecology of this virus.

Animals↗
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↗