Factors associated with measles resurgence in the United States in the post-elimination era

There have been growing concerns of a potential re-establishment of measles transmission in the United States (US) in the years to come. This study aims to explore potential factors underlying the resurgence of measles in the US by objectively assessing the associations between annual incidence rates (AIR), case importation, vaccination status and disease outbreaks. Data on measles transmission between January 1st, 2001 and December 31st, 2019 were obtained from the national centres for disease control and prevention (CDC) surveillance databases and other published reports. Changes in incidence rates over time were assessed by binomial regression models. Of the 3874 cases of measles in the US over the study period, 3506 (90.5%, 95% CI: 89.5-91.4) occurred in US residents. The AIR per million population in US residents over this period was 0.60 (95% CI: 0.59-0.61), with an overall significant increase over time (p = 0.011). The median percentage of imported and vaccinated cases were 36% [17.9-46.6] and 15% [12.1-23.2] respectively. There was a significant decrease in the percentage of imported cases (p < 0.001) but not of vaccinated cases (p = 0.159) over time. There was a moderate and weak negative correlation between the AIR and the percentage of imported and vaccinated cases respectively (r = -0.59 and r = -0.27 respectively). On multiple linear regression there was a significant linear association between the AIR and the number of outbreaks (p = 0.003) but not with the percentage of imported cases (p = 0.436) and vaccinated cases (p = 0.692), R2 = 0.73. Strong negative and positive correlations were seen between the number of outbreaks and the percentage of imported cases (r = -0.61) and the of number states affected (r = 0.88) respectively. Despite the overall reduction in the percentage of imported cases of measles over the past two decades, pockets of internal transmission of the disease following importation via increasing number of outbreaks in unvaccinated subpopulations, reinforced by vaccine hesitancy, account for the sustained increase in measles incidence rates in the US. Controlling indigenous transmission through efficient vaccination coverage in at-risk subpopulations and among international US travellers, improved disease surveillance and rapid outbreak containment are essential in curbing the measles resurgence.

Is short-term exposure to ambient fine particles associated with measles incidence in China? A multi-city study

BACKGROUND

China's rapid economic development has resulted in severe particulate matter (PM) air pollution and the control and prevention of infectious disease is an ongoing priority. This study examined the relationships between short-term exposure to ambient particles with aerodynamic diameter ≤2.5µm (PM_2.5) and measles incidence in China.

METHODS

Data on daily numbers of new measles cases and concentrations of ambient PM_2.5 were collected from 21 cities in China during Oct 2013 and Dec 2014. Poisson regression was used to examine city-specific associations of PM_2.5 and measles, with a constrained distributed lag model, after adjusting for seasonality, day of the week, and weather conditions. Then, the effects at the national scale were pooled with a random-effect meta-analysis.

RESULTS

A 10µg/m³ increase in PM_2.5 at lag 1day, lag 2day and lag 3day was significantly associated with increased measles incidence [relative risk (RR) and 95% confidence interval (CI) were 1.010 (1.003, 1.018), 1.010 (1.003, 1.016) and 1.006 (1.000, 1.012), respectively]. The cumulative relative risk of measles associated with PM_2.5 at lag 1-3 days was 1.029 (95% CI: 1.010, 1.048). Stratified analyses by meteorological factors showed that the PM_2.5 and measles associations were stronger on days with high temperature, low humidity, and high wind speed.

CONCLUSIONS

We provide new evidence that measles incidence is associated with exposure to ambient PM_2.5 in China. Effective policies to reduce air pollution may also reduce measles incidence.

Measles epidemiology in Mazandaran province, Iran, 2000-2002

To determine the incidence and characteristics of measles, cases reported to the Health Center for Diseases Control 2000-2002 were reviewed. Demographics data, vaccination status and its relation to occurrence the disease were analysed.

A total of 729 cases (270 women,162, 269, 298, over the 3 years) were reported. The annual incidence rates over the 3 years were 7.1, 11.9 and 12.7 for each 105 population. In full vaccinated subjects, 46.5% of the cases occurred and 39.9% of the cases had not been vaccinated.

Because of the high incidence rate of measles both in vaccinated and unvaccinated individuals, paying more attention to proper shipping and storing of vaccine, and even catch-up immunization for increasing herd immunity are recommended.

[An outbreak of measles among unvaccinated migrant population in Zhejiang province, from June to August, 2010]

OBJECTIVE

On July 6, 2010, the parents of a patient with confirmed measles reported several suspected measles patients with fever and rash in their village. An investigation was carried out to verify and understand the cause of the outbreak.

METHODS

Several suspected cases had an onset of fever and rash in this and other neighboring villages during June 1 to August 3, 2010. A confirmed case was a suspected case with measles-specific IgM identified in the serum. We conducted door-to-door visits and searched the Chinese Center for Disease Control and Prevention Information System to identify cases, also conducted a retrospective cohort study among migrant children aged 8 months-14 years to identify risk factors related to measles.

RESULTS

We identified 19 measles cases (17 confirmed case, 2 suspected cases) in the village, and all of them were migrants. Children aged 1-2 years had the highest attack rate (13%). The primary case-patient had onset on the day she arrived in this village (June 4, 2010). Caretakers from an unlicensed private clinic were providing service in the village but did not report the outbreak to the public health authority. The outbreak was identified only after receiving a report from the parents of one of the patients, by that time the outbreak had lasted for one month. The measles vaccine coverage rate was 81% among the 315 migrant children aged 8 months-14 years. Among the 61 unvaccinated children, those who reportedly being contacted a measles patient had a higher attack rate (14/16, 88%) than those who did not (2/45, 4.4%) (Relative risk = 20, Fisher's exact 95% confidence interval: 5.7-94).

CONCLUSION

The low measles vaccine coverage among migrant children and lack of measures taken on the incident, timely isolation diagnosis/reporting by the caretakers from the unlicensed private clinic etc. had contributed to this prolonged outbreak. Measures need to be taken to improve the immunization services for migrant populations and to enhance measles surveillance programs in the area.

Infection of cynomolgus macaques (Macaca fascicularis) and rhesus macaques (Macaca mulatta) with different wild-type measles viruses

Both rhesus and cynomolgus macaques have been used as animal models for measles vaccination and immunopathogenesis studies. A number of studies have suggested that experimental measles virus (MV) infection induces more-characteristic clinical features in rhesus than in cynomolgus monkeys. In the present study, both macaque species were infected with two different wild-type MV strains and clinical, virological and immunological parameters were compared. The viruses used were a genotype C2 virus isolated in The Netherlands in 1991 (MV-Bil) and a genotype B3 virus isolated from a severe measles case in Sudan in 1997 (MV-Sudan). Following infection, all rhesus monkeys developed a skin rash and conjunctivitis, which were less obvious in cynomolgus monkeys. Fever was either mild or absent in both species. Virus reisolation profiles from peripheral blood mononuclear cells and broncho-alveolar lavage cells and the kinetics of MV-specific IgM and IgG responses were largely identical in the two animal species. However, in animals infected with MV-Sudan, viraemia appeared earlier and lasted longer than in animals infected with MV-Bil. This was also reflected by the earlier appearance of MV-specific serum IgM antibodies after infection with MV-Sudan. Collectively, these data show that cynomolgus and rhesus macaques are equally susceptible to wild-type MV infection, although infection in the skin seems to follow a different course in rhesus macaques. MV-Sudan proved more pathogenic for non-human primates than MV-Bil, which may render it more suitable for use in future pathogenesis studies.

Distinguishing between primary measles infection and vaccine failure reinfection by IgG avidity assay

In this study in the Islamic Republic of Iran 365 measles cases were evaluated to distinguish between primary infection with measles and reinfection due to secondary vaccine failure. All cases previously confirmed by detection of specific IgM were tested for IgG avidity. A secondary immune response was seen in 18.4% of patients. All unvaccinated patients (16.7%) showed a primary immune response. Of 244 patients with documented vaccination, 75.8% showed a primary immune response and 24.2% showed a secondary immune response, thereby indicating a secondary vaccine failure. Almost all measles reinfections (99%) were seen in patients >10 years old, indicating that vaccination for 10-year-old children is recommended.

A mouse model of persistent brain infection with recombinant Measles virus

Measles virus (MV) nucleocapsids are present abundantly in brain cells of patients with subacute sclerosing panencephalitis (SSPE). This invariably lethal brain disease develops years after acute measles as result of a persistent MV infection. Various rodent models for MV infection of the central nervous system (CNS) have been described in the past, in which the detection of viral antigens is based on histological staining procedures of paraffin embedded brains. Here, the usage of a recombinant MV (MV-EGFP-CAMH) expressing the haemagglutinin (H) of the rodent-adapted MV-strain CAM/RB and the enhanced green fluorescent protein (EGFP) is described. In newborn rodents the virus infects neurons and causes an acute lethal encephalitis. From 2 weeks on, when the immune system of the genetically unmodified animal is maturating, intracerebral (i.c.) infection is overcome subclinically, however, a focal persistent infection in groups of neurons remains. The complete brain can be analysed in 50 or 100 microm slices, and infected autofluorescent cells are readily detected. Seven and 28 days post-infection (p.i.) 86 and 81% of mice are infected, respectively, and virus persists for more than 50 days p.i. Intraperitoneal immunization with MV 1 week before infection, but not after infection, protects and prevents persistence. The high percentage of persistence demonstrates that this is a reliable and useful model of a persistent CNS infection in fully immunocompetent mice, which allows the investigation of determinants of the immune system.

[Study on the relative risk factors of adult measles in a case-control study in Qingdao city]

OBJECTIVE

To explore the relative risk factors of adult measles in Qingdao city.

METHODS

Case-control study was used to collect the information from 70 adult measles cases and 140 controls. Information would include general social and demographic characteristics, history and times regarding measles vaccination, demography of the study of population etc.

RESULTS

The case group had lower proportion of measles vaccination (chi2 = 26.88, P < 0.05, OR = 5.12, 95% CI: 2.69 - 9.73) than the control group with statistical significance. The vaccination frequencies were stratified as three ranks: 0, 1, > or = 2 times for analysis. When having 0 and 1 time measles vaccination, no statistical significance was found in these two groups (chi2 = 1.86, P = 0.173), but there were statistical significance between 0 and > or = 2 times (chi2 = 45.24, P = 0.000, OR = 13.35, 95% CI: 5.80 - 30.71), 1 and > or = 2 times (chi2 = 26.23, P = 0.000, OR = 7.91, 95% CI: 3.37 - 18.59) in the two groups. It was also found that the proportion of floating population was higher in case group than that of the control group (chi2 = 21.60, P < 0.01, OR = 4.06, 95% CI: 2.21 - 7.45). At the same time, statistically significant correlation was found between adult measles and average family incomes (chi2 = 2.23, P < 0.05, OR = 2.08, 95% CI: 1.15 - 3.76) by single-factor statistical analysis.

CONCLUSION

Results showed that 'without history of measles vaccination' was key relative risk factor for the adult measles while being a part of 'floating population' and those having lower incomes were among vulnerable groups.

Subacute sclerosing panencephalitis: more cases of this fatal disease are prevented by measles immunization than was previously recognized

BACKGROUND

The most severe sequela of measles virus infection is subacute sclerosing panencephalitis (SSPE), a fatal disease of the central nervous system that generally develops 7-10 years after infection. From 1989 through 1991, a resurgence of measles occurred in the United States, with 55,622 cases of measles reported. The purpose of the present study was to identify cases of SSPE that were associated with the resurgence of measles and to calculate the risk of developing SSPE.

METHODS

Brain tissue samples obtained from 11 patients with a presumptive diagnosis of SSPE were tested for the presence of measles virus RNA. Measles virus genotypes were determined by reverse-transcription polymerase chain reaction (RT-PCR) and by analysis of the sequences of the PCR products. A search of the literature was conducted to identify reports of cases of SSPE in persons residing in the United States who had measles during 1989-1991.

RESULTS

The measles virus sequences derived from brain tissue samples obtained from 11 patients with SSPE confirmed the diagnosis of SSPE. For 5 of the 11 patients with SSPE who had samples tested by RT-PCR and for 7 patients with SSPE who were identified in published case reports, it was determined that the development of SSPE was associated with the measles resurgence that occurred in the United States during 1989-1991. The estimated risk of developing SSPE was 10-fold higher than the previous estimate reported for the United States in 1982.

CONCLUSIONS

Vaccination against measles prevents more cases of SSPE than was originally estimated.

Rubella, rubeola, and mumps in pregnant women: susceptibilities and strategies for testing and vaccinating

OBJECTIVE

To estimate rubella, rubeola, and mumps (MMR) susceptibilities in pregnant women and determine the percentage not immune to rubeola or mumps, depending on rubella immunity status. A secondary objective was to assess costs of vaccination and testing programs aimed at eliminating these viral susceptibilities to determine an optimal strategy.

METHODS

This was an observational study of women presenting for prenatal care. All women had MMR antibody titers measured. Viral susceptibilities were compared by age, gravidity, parity, and recall of vaccine booster. A logistic regression was performed to assess for predictors of MMR immunity. A cost comparison of different screening and vaccination strategies was performed.

RESULTS

Overall, 91 (9.4%) women were susceptible to rubella, 161 (16.5%) to rubeola, and 159 (16.3%) to mumps. Three hundred seventeen (32.6%) were susceptible to at least 1 virus, whereas only 17 (1.7%) were susceptible to all 3. Of the women who were immune to rubella, a large percentage were not immune to either rubeola or mumps (n = 226, 25.6%). Only 74.2% of women who knew they had a booster vaccine were immune to all components of the MMR vaccine. Receiving a booster was predictive of immunity to all 3 viruses. A cost analysis demonstrated that broader screening strategies are more comprehensive and more expensive.

CONCLUSION

The current screening and vaccine program has left many reproductive-aged women susceptible to rubella, rubeola, and mumps infections. Perhaps a more comprehensive viral screening program is needed to ensure immunity.

Dynamics of viral RNA synthesis during measles virus infection

We propose a reference model of the kinetics of a viral RNA-dependent RNA polymerase (vRdRp) activities and its regulation during infection of eucaryotic cells. After measles virus infects a cell, mRNAs from all genes immediately start to accumulate linearly over the first 5 to 6 h and then exponentially until approximately 24 h. The change from a linear to an exponential accumulation correlates with de novo synthesis of vRdRp from the incoming template. Expression of the virus nucleoprotein (N) prior to infection shifts the balance in favor of replication. Conversely, inhibition of protein synthesis by cycloheximide favors the latter. The in vivo elongation speed of the viral polymerase is approximately 3 nucleotides/s. A similar profile with fivefold-slower kinetics can be obtained using a recombinant virus expressing a structurally altered polymerase. Finally, virions contain only encapsidated genomic, antigenomic, and 5'-end abortive replication fragment RNAs.

Vaccine-associated "wild-type" measles

Measles is the most contagious of the childhood exanthems and is the leading cause of vaccine-preventable deaths in children, mostly in developing countries. The prodromal stage, consisting of high fever and the triad of cough, coryza, and conjunctivitis, is followed by a caudal progressing rash over a period of 2 to 3 days. With a worldwide vaccination program in place, mortality and morbidity have decreased substantially. Receipt of the live attenuated vaccine generally causes no or only mild side effects such as a low-grade fever and a subtle rash. We report a 1-year-old boy who, 10 days after vaccination, developed vaccine measles which was clinically indistinguishable from the natural disease. Vaccine virus was detected by polymerase chain reaction in the patient's nasopharyngeal secretions.

A new complication of stem cell transplantation: measles inclusion body encephalitis

Measles inclusion body encephalitis (MIBE) is a disease of the immunocompromised host and typically occurs within 1 year of acute measles infection or vaccination. We report a 13-year-old boy who had chronic granulomatous disease and presented 38 days after stem cell transplantation with afebrile focal seizures that progressed despite multiple anticonvulsants. After an extensive diagnostic evaluation, brain biopsy was performed, revealing numerous intranuclear inclusion bodies consistent with paramyxovirus nucleocapsids. Measles studies including reverse transcriptase-polymerase chain reaction and viral growth confirmed measles virus, genotype D3. Immunohistochemistry was positive for measles nucleoprotein. Despite intravenous ribavirin therapy, the patient died. MIBE has not been described in stem cell recipients but is a disease of immunocompromised hosts and typically occurs within 1 year of measles infection, exposure, or vaccination. Our case is unusual as neither the patient nor the stem cell donor had apparent recent measles exposure or vaccination, and neither had recent travel to measles-endemic regions. The patient had an erythematous rash several weeks before the neurologic symptoms; however, skin biopsy was consistent with graft-versus-host disease, and immunohistochemistry studies for measles nucleoprotein were negative. As measles genotype D3 has not been seen in areas where the child lived since his early childhood, the possibility of an unusually long latency period between initial measles infection and MIBE is raised. In addition, this case demonstrates the utility of brain biopsy in the diagnosis of encephalitis of unknown cause in the immunocompromised host.

Polarized glycoprotein targeting affects the spread of measles virus in vitro and in vivo

We have shown previously that basolateral targeting of plasmid-encoded measles virus (MV) F and H protein is dependent on single tyrosine residues in the cytoplasmic tails of the glycoproteins and is essential for fusion activity in polarized epithelial cells. Here, we present data on the functional importance of polarized glycoprotein expression for the cytopathic properties of infectious MV in culture and for pathogenesis in vivo. By the introduction of single point mutations, we generated recombinant viruses in which the basolateral targeting signal of either one or both glycoproteins was destroyed (tyrosine mutants). As a consequence, the mutated glycoproteins were predominantly expressed on the apical membrane of polarized Madin-Darby canine kidney cells. In contrast to parental MV, none of these virus mutants was able to spread by syncytia formation in polarized cells showing that the presence of both MV glycoproteins at the basolateral cell surface is required for cell-to-cell fusion in vitro. Using cotton rats as an animal model that allows MV replication in the respiratory tract, we showed that basolateral glycoprotein targeting is also of importance for the spread of infection in vivo. Whereas parental MV was able to spread laterally within the respiratory epithelium and from there to cells in the underlying tissue, tyrosine mutants infected only single epithelial and very few subepithelial cells. These data strongly suggest that basolateral targeting of MV glycoproteins helps to overcome the epithelial barrier and thereby facilitates the systemic spread of MV infection in vivo.

Long-term immunity to measles, mumps and rubella after MMR vaccination among children with bone marrow transplants

Measles, mumps and rubella (MMR) vaccine-induced long-term immunity was studied in 30 children with bone marrow transplants (BMT). Immunity at baseline for MMR was 13.3, 33.3 and 66.6%, respectively. MMR vaccination failed to induce adequate and persistent responses to measles and mumps; seropositivity at 1 and 12 months for measles was 26.6 and 23.3% and for mumps 46.6 and 36.6%, respectively. In contrast, 27 of 30 children with a BMT were immune to rubella 1 month after immunization and retained protective antibody levels at 12 months. The MMR-induced anamnestic responses to rubella among all responders were associated with the production of high avidity antibodies. We conclude that a single dose of MMR given at 2 years after BMT induces suboptimal and short-lived immune responses to measles and mumps; a second dose should be recommended for paediatric BMT recipients.

[Epidemiologic features of subacute sclerosing panencephalitis from clinical data of patients receiving a public aid for treatment]

In 1999, clinical data of 125 patients with subacute sclerosing panencephalitis (SSPE) were obtained by the Research Committee from local prefectural governments. The data were made by physicians treating the patients, and were submitted to the governments when the patients applied for the aid. By analyzing the data, we observed the epidemiologic features of the disease in Japan, and discussed the availability of the data as the source of epidemiologic researches. Of the 125 patients, 66 were males and 59 were females. The distribution of age at onset had a peak in 5-14 years of age with the average of 10.3 years. Among the 109 cases in which the time of infection was obvious, more than 80% suffered from measles before 2 years of age, in agreement with the hypothesis that measles infection in young age is a risk factor of SSPE. The interval between measles and the onset of SSPE was between 5 and 10 years in most cases, with average of 8.8 years, median of 4.3 years, ranging from 2 months to 23.6 years. Because the data contain some problems, we have to observe the epidemiologic features of SSPE in Japan based on multiple data sources including this one, considering their advantages and disadvantages.

Modulation of immune functions by measles virus

Measles virus remains among the most potent global pathogens killing more than 1 million children annually. A profound suppression of general immune functions occurs during and for weeks after the acute disease, which favors secondary infections. In contrast, virus-specific immune responses are efficiently generated, mediate viral control and clearance and confer a long-lasting immunity. Because they sense pathogen-associated molecular patterns, and subsequently initiate and shape adaptive immune responses, professional antigen-presenting cells (APC) such as dendritic cells are likely to play a key role in the induction and quality of the virus-specific immune response. Key features of immune suppression associated with measles virus, however, are compatible with interference with APC maturation and function and subsequent qualitative and quantitative alterations of T cell activation.

Beliefs of mothers in Asian countries and among Hmong in the United States about the causes, treatments, and outcomes of acute illnesses: an integrated review of the literature

An understanding of mothers' beliefs regarding the causes of illness, treatment, and outcome is an important component of culturally competent care. However, little is known about the beliefs of Asian parents related to acute illnesses. The purpose of our article is to synthesize what is known about the beliefs of mothers regarding the causes, treatment, and outcome of acute illnesses in Asian countries and Hmong in the United States. The literature review covers the period from 1990-2000. The electronic bibliographic databases explored included Pub Med, MEDLINE, HealthSTAR, CINAHL, and PsycINFO. Keywords used were beliefs, health beliefs, mothers or parents, cause of illness or etiology, treatment, diarrhea, acute respiratory infection, measles, Asia, and Hmong. A total of 15 articles were retrieved and examined. Using the matrix method, each article was evaluated according to five frames of reference: journal, purpose, sample, method, and findings. Content analysis was used to generate themes. Expressions of belief related to the causes of illnesses among mothers from Asian countries and Hmong who have emigrated from Laos to the United States of America were found to be quite similar. Beliefs about practices were primarily related to feeding and home care. The majority of mothers first provided treatment for their children using traditional practices. When the child did not recover, the mother sought medical advice.

Use of RT-PCR on oral fluid samples to assist the identification of measles cases during an outbreak

This study investigated the occurrence of mild modified measles cases during an outbreak in Niterói, RJ, Brazil by using RT-PCR on oral fluid samples. From August to December 1997 a total of 76 patients with rash were seen at the study sites. Confirmed diagnosis by serology was achieved in 47 cases: measles (39.5%), rubella (13.2%), HHV-6 (3.9%), human parvovirus B19 (3.9%), dengue fever (3%). For 19 of the 29 patients without a conclusive diagnosis paired serum and saliva samples were available for further tests. In four of them, measles virus RNA was detected by RT-PCR in saliva samples in the absence of specific IgM in serum samples. Vaccination histories obtained from three of the RT-PCR positive cases showed that individuals previously immunized can still be infected and contribute to the circulation of measles virus. This study demonstrated the usefulness of RT-PCR on non-invasive clinical samples for the investigation of measles cases.

Circulating D-dimer and thrombomodulin levels in acute febrile phase of measles

OBJECTIVES

Circulating D-dimer and thrombomodulin (TM) levels are now routinely measured in clinical laboratories. Plasma levels of D-dimer are used as a marker of fibrin formation and degradation, and serum TM is used to assess the state of endothelial cell injuries. While the levels of circulating D-dimer and TM have been investigated in many diseases, to our knowledge they have not been studied in patients with measles. We measured circulating levels of D-dimer in patients with measles to discuss whether fibrin formation and degradation occur and TM whether endothelial injury occur.

METHODS

The plasma levels of D-dimer and serum levels of alanine aminotransferase (ALT) and creatinine were measured of 14 adolescent and adult Japanese patients with measles, and the serum or plasma levels of TM of 10 of these 14 patients were measured in the acute febrile phase and convalescent afebrile phase with commercially available kits.

RESULTS

Plasma D-dimer levels were significantly higher in the acute febrile phase than in the convalescent afebrile phase in patients with measles, and no significant difference was shown in serum and plasma TM levels between the two phases. Plasma D-dimer levels were not correlated with serum or plasma TM levels in either phase. No significant differences were identified in the serum ALT and creatinine levels between the acute febrile and convalescent afebrile phases, and the levels of plasma D-dimer were not significantly correlated with the serum ALT levels.

CONCLUSIONS

Our results indicate that while clot formation and fibrinolysis may tend to occur in patients with the acute febrile phase of measles, there may be little risk that such patients will suffer endothelial injury.

Measles: a rare communicable disease in a child with renal transplantation

Measles is a rare communicable disease which may be fatal in renal transplant patients. Herein we present a patient with renal transplantation who had measles and who subsequently developed subacute measles encephalitis 4 months later. We recommend all children with chronic renal failure be vaccinated against measles before transplantation.

An immunohistochemical study of the distribution of the measles virus receptors, CD46 and SLAM, in normal human tissues and subacute sclerosing panencephalitis

We have compared the expression of the known measles virus (MV) receptors, membrane cofactor protein (CD46) and the signaling lymphocyte-activation molecule (SLAM), using immunohistochemistry, in a range of normal peripheral tissues (known to be infected by MV) as well as in normal and subacute sclerosing panencephalitis (SSPE) brain. To increase our understanding of how these receptors could be utilized by wild-type or vaccine strains in vivo, the results have been considered with regard to the known route of infection and systemic spread of MV. Strong staining for CD46 was observed in endothelial cells lining blood vessels and in epithelial cells and tissue macrophages in a wide range of peripheral tissues, as well as in Langerhans' and squamous cells in the skin. In lymphoid tissues and blood, subsets of cells were positive for SLAM, in comparison to CD46, which stained all nucleated cell types. Strong CD46 staining was observed on cerebral endothelium throughout the brain and also on ependymal cells lining the ventricles and choroid plexus. Comparatively weaker CD46 staining was observed on subsets of neurons and oligodendrocytes. In SSPE brain sections, the areas distant from lesion sites and negative for MV by immunocytochemistry showed the same distribution for CD46 as in normal brain. However, cells in lesions, positive for MV, were negative for CD46. Normal brain showed no staining for SLAM, and in SSPE brain only subsets of leukocytes in inflammatory infiltrates were positive. None of the cell types most commonly infected by MV show detectable expression of SLAM, whereas CD46 is much more widely expressed and could fulfill a receptor function for some wild-type strains. In the case of wild-type stains, which are unable to use CD46, a further as yet unknown receptor(s) would be necessary to fully explain the pathology of MV infection.

Current overview of the pathogenesis and prophylaxis of measles with focus on practical implications

Measles is one of the most important diseases of mankind, which is so highly contagious and evokes such persistent immunity that the virus cannot be sustained in a population of less than about 500,000 persons. The first of the licensed live virus vaccines against measles was developed empirically and was approved in 1963. It provides high level and lasting immunity and is a paradigm for solving major medical problems without really understanding them. In spite of means for control by prophylactic immunization, research on measles infection continues to be part of the effort to understand the pathogenesis of many different viruses, which may have important similarities and differences and provide important insights. Measles, usually, is spontaneously reversible and is a prime model for understanding virus-induced immunodeficiency disease (AIDS) which is rarely reversible. Much has been learned of basic immunology and vaccinology in measles through observation of the inappropriate use of vaccines of appropriate composition, and through inappropriate host response to measles vaccines of inappropriate composition. This review provides a current overview of selected highlights of measles, the virus, its immunopathogenesis, and its control by use of live virus vaccine which may lead to elimination of the disease and eventually to eradication of the virus.

MMR vaccine in HIV-infected children -- potential hazards?

Although given routinely as prophylaxis against wild-type measles to HIV-infected children, the live attenuated measles component of the MMR triple vaccine also possesses potential for disease. We document a case of measles proven to be caused by vaccine strain in a HIV-infected child here in the UK and discuss the clinical and immunological aspects. We also consider the new guidelines for MMR vaccination in HIV-infected children adopted last year in the USA.

[Analyses on the risk factors of Measles in Anhui province during 1998 and 1999]

OBJECTIVE

To evaluate the measures targeting measles control.

METHODS

Measles cases were studied serologically under AFP surveillance system.

RESULTS

The incidence was 1.36/100 000 in 1999. The incidence of children under 5 was 3.65/100 000, with 84.00% and 87.49% reduction, as compared with the incidence in 1991 and 1997 before intensified vaccination campaigns in children aged 1 - 6. The indicators of surveillance showed an improvement in 1999 than that in 1998.

CONCLUSION

Training for health staff at county, township, vallage levels played an important role in improving the sensibility and timeliness of measles surveillance system. Routine immunization is a key element in curbing measles outbreaks and reducing measles incidence.

[Analysis of clinical epidemiology for 208 patients of measles and some lessons learned]

OBJECTIVE

To survey the epidemic patterns and clinical characteristics of a relatively large scale measles epidemic in Shenzhen, 1998.

METHODS

Morbidity among permanent and temporary residents in 4 different age groups, related to their history of measles vaccination among the infant cases of <or= 8 month olds as well as measles histories of their mothers, and on history of the vaccination in > 8 month olds among the two types of residents. Using data originated from the hospital documents of 208 measles cases in 1998.

RESULTS

Among the total 208 cases: (1) Of 107 cases of temporary residents in age > 8 mon., 79.4% were unvaccinated while 41.7% were unvaccinated among 72 cases of permanent inhabitants in age > 8 mon.; (2) The two peaks fell on 9 month to 5 year olds (32.7%), in which predominant cases were permanent inhabitant, while among the 14 - 36 year group (33.7%) temporary resident accounted for 71.4%; (3) Among 208 cases, there were 29 in 3 - 7 mon. olds, taking up 14.0% of the whole, who all did not receive the vaccinations. Seventeen of the 29 cases (58.6%) of the said children had mothers with positive histories of measles while the infants manifested atypical mild measles. The rest 12 of the 29 cases (41.4%) whose mothers had an negative histories of contracting measles, 4 infants manifested typical measles and 8 atypical mild measles.

CONCLUSIONS

(1) One of the main causes of this epidemic was the unsound history of vaccination in the population; (2) In Shenzhen, preventive measures should focus on infants and young children among permanent inhabitants while focusing on adolescents and youths on temporary residents; (3) It was suggested that in Shenzhen, infants born to mothers without measles history or infants at the age borderline for measles immunization but without vaccination should receive it; Women in reproductive ages without measles history or vaccination should be considered as vaccination receivers.

Recombinant measles virus requiring an exogenous protease for activation of infectivity

Proteolytic cleavage of the fusion protein (F) is an important control mechanism of the biological activity of paramyxoviruses. The sequence R-R-H-K-R(112) at the cleavage site of the F protein of measles virus (MV) was altered by site-directed mutagenesis to R-N-H-N-R(112), which is not recognized by the ubiquitous cellular protease furin. When transiently expressed in cell cultures standard F protein was cleaved, whereas the mutant remained in the uncleaved form. Syncytium formation by the mutant that was analysed after coexpression with haemagglutinin protein depended on the presence of trypsin. Recombinant MV containing the mutation required trypsin activation for fusion and infectivity in cell culture. Intranasal infection of transgenic mice susceptible to MV infection (Ifnar(tm)-CD46Ge) resulted in a moderately productive infection and inflammation of the lung. In contrast to parental virus, intracerebral inoculation did not induce neural disease. The possible effects of the change in cleavage activation on tissue tropism and pathogenicity are discussed.

What is the cause of a rash after measles-mumps-rubella vaccination?

Surveillance and laboratory confirmation of measles will increase in importance as Australia implements enhanced measles control. We describe a 17-month-old child with fever and rash after measles-mumps-rubella vaccination. Detection of vaccine-strain measles virus in his urine by polymerase chain reaction confirmed the diagnosis of a vaccine reaction rather than wild-type measles. We propose that measles virus should be sought and identified as vaccine or wild-type virus when the relationship between vaccination and measles-like illness is uncertain.

Replication of clinical measles virus strains in hispid cotton rats

An alternative model to nonhuman primates to study measles virus (MV) pathogenesis, to evaluate potential MV vaccines, or to screen for potential antivirals effective against this virus is highly desirable. The laboratory-adapted Edmonston strain of MV has been reported to replicate in the lungs of hispid cotton rats following intranasal inoculation, immunosuppress infected animals, and disseminate widely from the lungs, making these animals a candidate model. However, clinical MV strains have generally not been found to grow in these animals, limiting the utility and acceptance of this model. In the present studies we demonstrate reproducible replication of several clinical MV strains in hispid cotton rats. As with the Edmonston strain, leukocytes appear to be the primary target cells of these viruses following intranasal inoculation, and extrapulmonary dissemination is common. It is also demonstrated that prior MV infection or immunization of test animals with MV vaccine prevents pulmonary tract infection. These findings should make the MV-cotton rat model more acceptable.

Etiology of measles- and rubella-like illnesses in measles, mumps, and rubella-vaccinated children

The viral etiology of measles- or rubella-like illnesses after MMR (measles, mumps, and rubella) vaccination was studied prospectively in 993 acutely ill Finnish children with fever and rash in 1983-1995. Their sera were tested for adeno-, entero-, and parvovirus B19 antibodies. Sera of 300 children <4 years old were also tested for human herpesvirus 6 (HHV-6) antibodies. Measles and rubella had been excluded by previous antibody testing. Serologic diagnosis of adeno-, entero-, or parvovirus infection was based on EIA (IgM or IgG antibodies) and that of HHV-6 on indirect immunofluorescence. A viral etiology was verified in 368 cases, most commonly parvovirus (20%), followed by enterovirus (9%) and adenovirus (4%). Among young children, HHV-6 infection was found in 37 (12%). Thirty-eight children (4%) had double infections. This study confirms that measles- or rubella-like illnesses in MMR-vaccinated children are often caused by other viruses. Each suspected vaccine failure requires laboratory confirmation to maintain reliable surveillance and control and to establish the specific etiology of the disease.

Role of CD46 in measles virus infection in CD46 transgenic mice

The susceptibility of CD46 (human membrane cofactor protein) transgenic mice to measles virus (MV) infection was investigated. Cell cultures (lung and kidney) established from transgenic and control mice showed that although both could be infected only those from the CD46+ mice gave fusion. A complete round of replication with the release of infectious virus was detected exclusively in the transgenic cell cultures whose permissiveness to MV was markedly less than that of Vero cells. The ability of MV to replicate in vivo in mice was studied using both vaccine and laboratory-adapted wild-type strains of virus. After intraperitoneal and intranasal inoculations of transgenic mice, virus replication could not be detected. In contrast intracerebral inoculation induced infection in both transgenic and nontransgenic mice. Our results from in vitro infection studies support the hypothesis that CD46 is a major host cell factor involved in the MV-induced fusion process and MV entry. The studies further indicate that MV tropism is not governed solely by the expression of the CD46 gene and that the high efficiency of the replicative cycles characteristic of fully permissive host cells requires additional factors, which are lacking in both transgenic and nontransgenic mice.

[A case of measles encephaloneuropathy in a pregnant women]

We reported a patient with measles encephaloneuropathy. A 26-year-old woman in her 15th week of gestation became febrile and developed cutaneous eruption typical of measles on July 1 1997. Five days after appearance of the rash, fetal death was identified and the fetus was removed. Following the operation, she became comatous. Neurological examination revealed neck stiffness, flaccid paralysis of the four limbs, and decreased sweating in the lower limbs. CSF protein was 143 mg/dl with cell count of 1365/mm3. Myelin basic protein in CSF was positive. High titers of antimeasles antibodies were found in the serum and the cerebrospinal fluid. EEG revealed a predominance of slow waves. In MRI obtained earlier in her illness, high signal intensity areas were noted to spread in the brain stem and external capsule on T2-weighted images. However, T1-weighted image was unremarkable. Serial electrophysiological studies suggested demyelination of the motor nerves. With combination of methylprednisolone and immunoglobulin therapy, she made a remarkable recovery without any neurologic sequelae. We believe that the measles encephalitis in our patient is predominantly demyelinating due to an immunologic reaction in a pathophysiological aspect. We should pay attention to coincident poly-radiculoneuropathy in the early stage of measles encephalopathy.

Subacute sclerosing panencephalitis manifesting as viral retinitis: clinical and histopathologic findings

PURPOSE AND METHODS

To describe the clinical and histopathologic features of a patient with viral retinitis secondary to subacute sclerosing panencephalitis.

RESULTS

The patient was a human immunodeficiency virus-negative intravenous drug abuser with an acute retinitis that later progressed to encephalitis despite aggressive treatment for possible viral, protozoal, bacterial, and rickettsial infections. The patient had many of the characteristic findings of subacute sclerosing panencephalitis, including a history of measles in early childhood, myoclonus, periodic complexes on electroencephalographic testing, persistently elevated serum and cerebrospinal fluid antimeasles immunoglobulin G (IgG) titers, and a cerebrospinal fluid oligoclonal IgG gammopathy. Ultrastructural examination demonstrated numerous filamentous microtubular intranuclear viral inclusions in the nuclear layers of the retina consistent with the measles virus. This case is unusual in that our patient developed subacute sclerosing panencephalitis later in life and because there was an 8-year period between presumed viral infections in the two eyes.

CONCLUSIONS

An acute retinitis in an intravenous drug abuser is not always caused by human immunodeficiency virus-related infections; not all viral retinitis responds to therapy; and mortality as well as the usual morbidity may be associated with viral retinitis. One might consider the diagnosis of subacute sclerosing panencephalitis in a young person with an acute retinitis with little or no vitreal inflammation and lack of response to anticytomegalovirus and antitoxoplasmosis therapy.

Five cases of measles secondary vaccine failure with confirmed seroconversion after live measles vaccination

We report 5 patients with secondary vaccine failure (SVF) who were infected with natural measles 2, 5, 5, 7 and 12 years, respectively, after vaccination with further attenuated live measles vaccine during infancy. Their seroconversion had been confirmed after vaccination. Three of the 5 patients had mild (modified) measles, while the remaining 2 patients had typical measles. The hemagglutination inhibition antibody titers to measles virus in paired acute and convalescent sera showed a secondary response pattern in 4/5 patients, and a primary response pattern was present in the remaining patient. Measles IgM antibodies were present in all patients during the convalescent stage. The patient with the primary response pattern may have had a decrease in the B cell memory during the 5-year period between vaccination and infection. This may be the first SVF case report that confirms the existence of completely waning immunity in recipients of the further attenuated live measles vaccines.

Clinical problems in measles case management

Measles remains one of the leading causes of childhood morbidity and mortality in developing countries. The World Health Organization has identified effective case management as one of the specific strategies to reduce the burden of this disease. The purpose of this article is to review the aetiology, natural history, treatment and outcome of the common clinical problems associated with measles with a view to identifying possible deficiencies in case management. Complications such as pneumonia, diarrhoea, croup and malnutrition have been well defined in terms of their relative contribution to morbidity and mortality. However, there are few published data on the aetiology and natural history of these specific complications. Such data are crucial for rational case management strategies. Data on treatment of measles and its complications are limited and the role of antibiotic prophylaxis and therapy is unclear. The only specific research focus on case management during the last decade has been vitamin A therapy. There is a continuing need for community and hospital-based studies on the natural history of measles and its complications, the aetiology of these complications and intervention strategies that will improve measles case management.