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BACKGROUND: Despite the introduction of rubella-containing vaccine into routine immunization in 1977, rubella has not been eliminated in Japan. This study aimed to validate the immunization strategy and to highlight the crucial elements of elimination program. METHODS: We scrutinized cases of rubella and congenital rubella syndrome (CRS). Additionally, we analyzed the national vaccination coverage, seroprevalence, and number of maternal rubella-related spontaneous or artificial fetal deaths. RESULTS: The shift from selective to universal immunization significantly reduced rubella cases coupled with increased seroprevalence in children. However, rubella resurged in 2012-2013 and 2018-2019, which was virologically and serologically confirmed to be associated with imported rubella virus (RuV) and susceptible males. Although the disease burden of CRS may have been suppressed in the past by the large number of spontaneous or artificial fetal deaths, the incidence rate of CRS was comparable to that of the 1960s to 1980s. Cases of breakthrough infection and CRS were identified in females who were considered to have a history of single-dose vaccination. CONCLUSIONS: Even with universal immunization, future epidemics and severe outcomes cannot be prevented unless immunization gaps are closed. Furthermore, CRS and breakthrough infection are not completely prevented by single-dose vaccination, indicating the need for second-dose vaccination.
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BACKGROUND: Measles is a contagious viral disease causing infant mortality in developing countries without vaccination programs. In Japan, measles vaccination was launched in 1978, surveillance commenced in 1981, and elimination was achieved in 2015. This was due to improved, legally required surveillance methods and vaccine programs. METHODS: The data sets of sentinel (1982-2007) and notifiable (2008-2021) disease surveillance, as well as the vaccination coverage, detected genotypes, and seroepidemiology during the study period in Osaka Prefecture, were analyzed. Additionally, the trend under the current notifiable surveillance was compared before (2008-2014) and after (2015-2021) measles elimination. RESULTS: Under sentinel surveillance, 51,107 cases were reported, predominantly infants aged 1-4 years (63.6 %). Under notifiable disease surveillance, the 781 patients were predominantly in their 20s-30s (43.7 %). From 2000, the age of the major susceptible group increased due to the rise in vaccination coverage, which exceeded 95% for the first dose in 1998 and 90% for the second dose in 2009. Consistent with these data, seroprevalence exceeded 95% in 2011. However, the geometric mean of the antibody titer showed a decreasing trend with a falling number of patients. Compared with before and after measles elimination, the number of modified measles cases increased from 10.1% to 48.2%. During the study period, 398 strains comprising eight genotypes were identified, and the dominant type changed over time. After measles elimination, genotypes B3 and D8, derived from imported cases, became predominant. CONCLUSIONS: Improved vaccination coverage and surveillance reduced measles cases and increased herd immunity. However, the lack of a booster effect due to the low incidence of measles caused waning antibody titers despite high seroprevalence, which may contribute to the rising rate of vaccine failures causing modified measles. Careful monitoring of measles incidence and herd immunity are necessary for measles eradication.
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Sarampo , Lactente , Humanos , Estudos Soroepidemiológicos , Japão/epidemiologia , Sarampo/epidemiologia , Sarampo/prevenção & controle , Vacina contra Sarampo/uso terapêutico , Vírus do Sarampo/genética , VacinaçãoRESUMO
Our knowledge of the regulatory mechanisms that govern the replication of the rubella virus (RV) in human cells is limited. To gain insight into the host-pathogen interaction, we conducted a loss-of-function screening using the CRISPR-Cas9 system in the human placenta-derived JAR cells. We identified sphingomyelin synthase 1 (SGMS1 or SMS1) as a susceptibility factor for RV infection. Genetic knockout of SGMS1 rendered JAR cells resistant to infection by RV. The re-introduction of SGMS1 restored cellular susceptibility to RV infection. The restricted step of RV infection was post-endocytosis processes associated with the endosomal acidification. In the late phase of the RV replication cycle, the maintenance of viral persistence was disrupted, partly due to the attenuated viral gene expression. Our results shed light on the unique regulation of RV replication by a host factor during the early and late phases of viral life cycle.
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Erythema infectiosum, caused by human parvovirus B19 (B19V), is difficult to diagnose by its clinical symptoms and is often misdiagnosed as measles or rubella. Timely confirmation of measles/rubella or other viral etiologies via laboratory tests can provide an accurate picture of the infection status, which can appropriate response. The purpose of this study was to determine the contribution of B19V as an etiological agent for fever-rash in suspected cases of measles and rubella in Osaka Prefecture between 2011 and 2021. Of 1356 suspected cases, 167 were confirmed with measles and 166 with rubella using nucleic acid testing (NAT). Of the remaining 1023 cases, 970 from which blood specimens could be obtained were screened by real-time polymerase chain reaction for B19V, from which 136 (14%) tested positive. Of the positives cases, 21% were young children (9 years and younger), while 64% were adults (20 years and older). Phylogenetic tree analysis showed that 93 samples belonged to genotype 1a. The importance of B19V in the etiology of fever-rash illness was revealed in this study. The importance of laboratory diagnosis by NAT in maintaining the status of measles elimination and to eliminate rubella was reaffirmed.
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Exantema , Sarampo , Parvovirus B19 Humano , Rubéola (Sarampo Alemão) , Criança , Adulto , Humanos , Pré-Escolar , Parvovirus B19 Humano/genética , Filogenia , Japão/epidemiologia , Anticorpos Antivirais , Imunoglobulina M , Rubéola (Sarampo Alemão)/diagnóstico , Rubéola (Sarampo Alemão)/epidemiologia , Rubéola (Sarampo Alemão)/complicações , Sarampo/diagnóstico , Sarampo/epidemiologiaRESUMO
BACKGROUND: Since the first isolation of rubella virus (RuV) in 1962, comprehensive data regarding the quantitative evaluation of RuV shedding remain unavailable. In this study, we evaluated the shedding of viral RNA and infectious virus in patients with acute RuV infection. STUDY DESIGN: We analyzed 767 specimens, including serum/plasma, peripheral blood mononuclear cells (PBMCs), throat swabs, and urine, obtained from 251 patients with rubella. The viral RNA load and the presence of infectious RuV were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and virus isolation. RESULTS: Virus excretion peaked 0-2 days after rash onset and decreased over time. The median viral RNA load dropped to an undetectable level on day 3 after rash onset in serum/plasma, day 2 in PBMCs, days 10-13 in throat swabs, and days 6-7 in urine. Infectious virus could be isolated for up to day 2 after rash onset in serum/plasma, day 1 in PBMCs, days 8-9 in throat swabs, and days 4-5 in urine. The minimum viral RNA load that allowed virus isolation was 961 copies/mL in serum/plasma, 784 copies/mL in PBMCs, 650 copies/mL in throat swabs, and 304 copies/mL in urine. A higher viral RNA load indicated a higher likelihood of the presence of infectious virus. CONCLUSION: These findings would contribute to improve algorithms for rubella surveillance and diagnosis. In addition, this study indicates that the results of RT-qPCR enable efficient rubella control by estimating candidate patients excreting infectious virus, which could help prevent viral transmission at an early stage and eliminate rubella ultimately.
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Exantema , Rubéola (Sarampo Alemão) , Humanos , Vírus da Rubéola/genética , RNA Viral/genética , Leucócitos Mononucleares , Rubéola (Sarampo Alemão)/diagnóstico , Eliminação de Partículas ViraisRESUMO
Global efforts are underway to eliminate measles and rubella, and active viral surveillance is the key to achieving this goal. In addition, the World Health Organization announced guidelines for handling materials potentially infectious for poliovirus (PV) to minimize the risk of PV reintroduction and to achieve PV eradication. To support global efforts, we established new PV-non-susceptible cell lines that are useful for the isolation of measles virus (MeV) and rubella virus (RuV) (Vero ΔPVR1/2 hSLAM+). In the cell lines, MeV and RuV replicated efficiently, with no concern regarding PV replication.
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Sarampo , Poliovirus , Rubéola (Sarampo Alemão) , Animais , Chlorocebus aethiops , Humanos , Células Vero , Sarampo/epidemiologia , Vírus do Sarampo , Receptores Virais/genética , Vírus da RubéolaRESUMO
Japan is one of the countries conducting longitudinal serosurveillance of vaccine-preventable diseases. We conducted surveillance of the local measles-specific antibody titer, calculated the effective reproduction number (Re), and compared data of four terms: term 1, 2003-2006 (before the introduction of the second shot of measles-containing vaccine); term 2, 2007-2010 (early term toward measles elimination); term 3, 2011-2014 (later term toward measles elimination); and term 4, 2015-2020 (after elimination of measles in Japan). Approximately 250 sera from volunteers aged 0 to ≥ 40 years were collected and examined for measles-specific IgG using the gelatin particle agglutination (PA) method annually from 2003 to 2020. Seroprevalence and the geometric mean of the PA antibody titer were examined by term. Re was calculated using the age-dependent proportion immune and contact matrix for each term. Of the 4,716 sera, 886 in term 1, 1,217 in term 2, 1,069 in term 3, and 1,544 in term 4 were collected. The seroprevalence gradually increased from term 1 (88.3% CI 86.0-90.3) to term 4 (95.7% CI 94.6-96.7), and the seroprevalence of term 1 was significantly lower than those of other terms (Fisher's exact test, p < 0.001), with PA titer ≥ 16 as positive. By contrast, PA antibody titers significantly decreased from term 1 (median 1,024) to term 4 (median 256) (Mann-Whitney U test, p < 0.001). With the protection level (PA titer ≥ 128 and ≥ 256) as positive, Re gradually increased from term 1 (1.8 and 2.3) to term 4 (2.5 and 4.8, respectively). Waning levels of measles antibodies potentially increase the measles susceptibility in Osaka, Japan. This trend might imply a limitation of vaccine-induced immunity in the absence of a natural booster for wild strains after measles elimination. This study provides a cue for maintaining continuous measles elimination status in the future.
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Imunidade Coletiva , Sarampo , Humanos , Estudos Soroepidemiológicos , Japão/epidemiologia , Gelatina , Sarampo/epidemiologia , Sarampo/prevenção & controle , Vacina contra Sarampo , Anticorpos Antivirais , Imunoglobulina G , VacinaçãoRESUMO
This study investigated the correlation between biochemical markers and viral load among 38 measles cases, including 15 immunologically naive patients and 23 patients with secondary vaccine failure (SVF). We examined four biochemical markers, namely, aspartate aminotransferase, alanine aminotransferase, C-reactive protein, and lactate dehydrogenase (LDH) and their relationship between virus genome copy numbers in peripheral blood mononuclear cells (PBMCs) and throat swabs as well as the concentration of measles-specific IgG. Although viral genome copies in both clinical specimens showed a significant correlation with specific IgG concentration, they had a higher correlation in PBMCs (Pearson's product-moment correlation coefficient, -0.662; p < .0001) than in throat swabs (Spearman's rank correlation coefficient, -0.443; p = .0078). The viral load in PBMCs also significantly correlated with LDH values (correlation coefficient, 0.360; p = .036). Thus, the serum LDH level might be a potential auxiliary indicator to distinguish immunologically naive patients with measles from those with SVF.
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Sarampo , Anticorpos Antivirais , Biomarcadores , Humanos , Imunoglobulina G , L-Lactato Desidrogenase , Leucócitos Mononucleares , Vacina contra Sarampo , Vírus do Sarampo/genética , Vírus do Sarampo/imunologia , Carga ViralRESUMO
Since the elimination of the measles virus, patients with vaccination records for the measles-containing vaccine have increased in Japan. According to several studies, the transmission risk from previously immunized patients, especially those with secondary vaccine failure (SVF), is lower than that from those with primary measles infections. Immunological features of SVF were identified per specific immunoglobulin G (IgG) induction with high avidity and high plaque reduction neutralization antibody concentration. However, the virological features of SVF have not been well investigated. To examine not only immunological but also virological differences between SVF and immunologically naive patients, throat swabs and blood and urine specimens of 25 patients with confirmed measles infection after an outbreak at the Kansai International Airport in 2016 were analyzed. Patients were categorized as naive (n = 3) or with SVF (n = 22) based on measles-specific IgG antibody concentrations and their avidity. Virus isolation and quantitative real-time polymerase chain reaction were performed to quantify the viral load in clinical specimens and estimate the infectivity in each specimen. The number of viral genome copies in the blood specimens of those with SVF was significantly different and approximately 1 out of 100 of that in immunologically naive patients. However, genome copy numbers in throat swabs and urine specimens were not significantly different between the groups. The virus was isolated only from those in the naive group. Our study indicated low transmission risk of the virus in patients with SVF.
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Aeroportos , Anticorpos Antivirais/sangue , Surtos de Doenças/estatística & dados numéricos , Vacina contra Sarampo/imunologia , Sarampo/epidemiologia , Sarampo/transmissão , Adulto , Anticorpos Neutralizantes/sangue , Feminino , Genoma Viral , Humanos , Imunização Secundária/estatística & dados numéricos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Japão , Masculino , Sarampo/sangue , Sarampo/imunologia , Vírus do Sarampo/genética , Vírus do Sarampo/imunologia , Vírus do Sarampo/isolamento & purificação , Vacinação , Carga Viral , Adulto JovemAssuntos
Epidemias , Rubéola (Sarampo Alemão)/epidemiologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Rubéola (Sarampo Alemão)/prevenção & controle , Vacina contra Rubéola/administração & dosagem , Adulto JovemRESUMO
During the elimination stage of measles, the development of such disease in individuals who received measles-containing vaccine (MCV) is a concern from an epidemiological standpoint. A few cases in which measles was transmitted from a patient who received two doses of MCV have been reported. However, whether such transmissions were caused by primary vaccine failure (PVF) or secondary vaccine failure (SVF) remains unclear. All patients suspected of measles in Osaka Prefecture between November and December 2018 were enrolled. Data about age, gender, immunization record, and clinical signs were obtained. Laboratory examinations were performed, which included virus isolation in tissue culture, a nucleic acid test based on virus-specific real-time polymerase chain reaction and humoral responses to the measles virus measuring immunoglobulin (Ig) M, IgG, avidity of IgG, and neutralizing antibody concentration. The measles outbreak comprised 10 laboratory confirmed cases, including three secondary and six tertiary patients. Among them, three secondary patients were unvaccinated. The index case had received two MCV doses, and the six tertiary patients were vaccinated. Both the index and tertiary patients had high specific IgG concentration with high avidity. In particular, the index patient had a markedly high neutralization antibody concentration of 425,590 mIU/mL, which indicated immunological SVF. This study first reported about measles transmission from an individual with SVF who received two vaccination doses. To prevent measles transmission and outbreak particularly in countries where measles was almost eliminated, patients with SVF for measles should be cautiously monitored.
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Surtos de Doenças , Vacina contra Sarampo/administração & dosagem , Sarampo , Falha de Tratamento , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Afinidade de Anticorpos , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Japão , Sarampo/epidemiologia , Sarampo/prevenção & controle , Sarampo/transmissão , Vírus do Sarampo , VacinaçãoRESUMO
Genotyping evidence that supports the interruption of endemic measles virus (MV) transmission is one of the essential criteria to be verified in achieving measles elimination. In Japan since 2014, MV genotype analyses have been performed for most of the measles cases in prefectural public health institutes nationwide. With this strong molecular epidemiological data, Japan was verified to have eliminated measles in March, 2015. However, even in the postelimination era, sporadic cases and small outbreaks of measles have been detected repeatedly in Japan. This study investigated the nationwide molecular epidemiology of MV between 2008 and 2017. The 891 strains in the total period between 2008 and 2017 belonged to seven genotypes (D5, D4, D9, H1, G3, B3, and D8) and 124 different MV sequence variants, based on the 450-nucleotide sequence region of the N gene (N450). The 311 MV strains in the postelimination era between 2015 and 2017 were classified into 1, 7, 8, and 32 different N450 sequence variants in D9, H1, B3, and D8 genotypes, respectively. Analysis of the detection period of the individual N450 sequence variants showed that the majority of MV strains were detected only for a short period. However, MV strains, MVs/Osaka.JPN/29.15/ [D8] and MVi/Hulu Langat.MYS/26.11/ [D8], which are named strains designated by World Health Organization (WHO), have been detected in many cases over 2 or 3 years between 2015 and 2017. The WHO-named strains have circulated worldwide, causing outbreaks in many countries. Epidemiological investigation revealed repeated importation of these WHO-named strains into Japan. To demonstrate the elimination status (interruption of endemic transmission) in situations with repeated importation of the same strains is challenging. Nevertheless, the detailed sequence analysis of individual MV strains and chronological analysis of these strains provided sufficient evidence to show that Japan has still maintained its measles elimination status in 2017.
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A total of 300 patients with nucleic acid test-confirmed rubella, mostly adults, were investigated to determine the clinical value of a rubella-specific IgM test using an EIA kit. IgM titers increased after rash onset, the median IgM titer being significantly higher 3 days post-onset than on previous days (P < 0.0001). Similarly, the IgM-positive rate at 3 days post-onset (61.5%) was significantly higher than on previous days (P < 0.0001). This IgM test against rubella at 3 days or more post-disease onset provides the clinically relevant information.
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Técnicas de Laboratório Clínico/métodos , Técnicas Imunoenzimáticas/métodos , Imunoglobulina M/sangue , Rubéola (Sarampo Alemão)/diagnóstico , Rubéola (Sarampo Alemão)/imunologia , Adolescente , Adulto , Anticorpos Antivirais/análise , Criança , Pré-Escolar , Feminino , Humanos , Imunoglobulina G/sangue , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Vírus da Rubéola/imunologia , Soro/imunologia , Fatores de Tempo , Adulto JovemRESUMO
Although rubella is epidemic in Indonesia, the phylogenetic profile of circulating rubella virus strains has not been clarified. In 2017, rubella virus was detected in 2 travelers who returned from Indonesia to Japan. These strains were classified into genotype 1E lineage 2, which may be an indigenous strain in Indonesia.
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Vírus da Rubéola/isolamento & purificação , Rubéola (Sarampo Alemão)/diagnóstico , Viagem , Adulto , Diagnóstico Diferencial , Genótipo , Humanos , Indonésia , Japão , Masculino , Filogenia , Rubéola (Sarampo Alemão)/prevenção & controle , Rubéola (Sarampo Alemão)/virologia , Vírus da Rubéola/classificação , Vírus da Rubéola/genéticaRESUMO
A large rubella outbreak occurred in Japan 2013, and 14,344 rubella and 45 congenital rubella syndrome (CRS) cases were reported. At that time, the populational immunity was above the protective threshold assessed by hemmaglutination inhibition (HI) titer. The genotype 2B rubella virus (RV) strains were responsible for the outbreak, which are non-indigenous in Japan. In this work, a cell-based high throughput assay was established to measure the neutralizing antibody (NA) titer against circulating RV isolates. RV infection poorly induces cytopathic effects in tissue culture, preventing the casual measurement of NA titer. Our assay system has overcome this hurdle. Using this assay, we re-evaluated the antibody prevalence rate against circulating viral isolates using human sera collected before the outbreak. Individuals with protective IgG titer (≥10 IU/ml) represented 88.1% of the population. Consistently, 85.2% of the population had protective neutralizing antibody titers (≥1:8) against the vaccine strain. In contrast, 50.5% of the population had protective neutralizing antibody titers against circulating genotype 2B RV strains. These data suggest that the herd immunity assessed by HI titer should have been appreciated deliberately.
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Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Ensaios de Triagem em Larga Escala/métodos , Vírus da Rubéola/imunologia , Rubéola (Sarampo Alemão)/diagnóstico , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Genótipo , Testes de Inibição da Hemaglutinação , Humanos , Imunidade Coletiva , Imunoglobulina G/sangue , Lactente , Recém-Nascido , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Rubéola (Sarampo Alemão)/epidemiologia , Vírus da Rubéola/genética , Adulto JovemRESUMO
BACKGROUND: An easy and reliable assay for detection of the rubella virus is required to strengthen rubella surveillance. Although a TaqMan RT-PCR assay for detection of the rubella virus has been established in Japan, its utility for diagnostic purposes has not been tested. OBJECTIVES: To allow introduction of the TaqMan RT-PCR into the rubella surveillance system in Japan, the sensitivity of the assay was determined using representative strains for all genotypes and clinical specimens. STUDY DESIGN: The detection limits of the method for individual genotypes were examined using viral RNA extracted from 13 representative strains. The assay was also tested at 10 prefectural laboratories in Japan, designated as local reference laboratories for measles and rubella, to allow nationwide application of the assay. RESULTS: The detection limits and amplification efficiencies of the assay were similar among all the representative strains of the 13 genotypes. The TaqMan RT-PCR could detect approximately 90% of throat swab and urine samples taken up to 5days of illness. These samples were determined positive by a highly sensitive nested RT-PCR. CONCLUSIONS: The TaqMan RT-PCR could detect at least 10 pfu of rubella virus. Although the sensitivity was somewhat lower than that of the conventional nested RT-PCR, the TaqMan RT-PCR could be more practical to routine tests for rubella laboratory diagnosis and detection in view of the rapid response and reducing risks of contamination.
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Reação em Cadeia da Polimerase em Tempo Real/métodos , Vírus da Rubéola/isolamento & purificação , Rubéola (Sarampo Alemão)/diagnóstico , Feminino , Humanos , Japão , Masculino , Faringe/virologia , RNA Viral/genética , Vírus da Rubéola/genética , Sensibilidade e Especificidade , Urina/virologiaRESUMO
We investigated Legionella contamination in bath water samples, collected from 68 bathing facilities in Japan, by culture, culture with amoebic co-culture, real-time quantitative PCR (qPCR), and real-time qPCR with amoebic co-culture. Using the conventional culture method, Legionella pneumophila was detected in 11 samples (11/68, 16.2%). Contrary to our expectation, the culture method with the amoebic co-culture technique did not increase the detection rate of Legionella (4/68, 5.9%). In contrast, a combination of the amoebic co-culture technique followed by qPCR successfully increased the detection rate (57/68, 83.8%) compared with real-time qPCR alone (46/68, 67.6%). Using real-time qPCR after culture with amoebic co-culture, more than 10-fold higher bacterial numbers were observed in 30 samples (30/68, 44.1%) compared with the same samples without co-culture. On the other hand, higher bacterial numbers were not observed after propagation by amoebae in 32 samples (32/68, 47.1%). Legionella was not detected in the remaining six samples (6/68, 8.8%), irrespective of the method. These results suggest that application of the amoebic co-culture technique prior to real-time qPCR may be useful for the sensitive detection of Legionella from bath water samples. Furthermore, a combination of amoebic co-culture and real-time qPCR might be useful to detect viable and virulent Legionella because their ability to invade and multiply within free-living amoebae is considered to correlate with their pathogenicity for humans. This is the first report evaluating the efficacy of the amoebic co-culture technique for detecting Legionella in bath water samples.
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Fontes Termais/microbiologia , Legionella pneumophila/isolamento & purificação , Acanthamoeba castellanii , Banhos , Técnicas de Cocultura , Japão , Legionella/genética , Logradouros Públicos , Reação em Cadeia da Polimerase em Tempo RealRESUMO
In 2013, a rubella outbreak was observed in Japan, Romania, and Poland. The outbreak in Japan was accompanied by an increase of measles reports, especially from a region where measles is highly controlled. This was attributed to the adult populations affected by this rubella outbreak, similarity of clinical signs between rubella and measles, sufficiently small impact of measles outbreaks from neighboring nations, and elimination levels of measles endemicity. Current and future concerns for measles control are discussed.