Use of a rapid digital microfluidics-powered immunoassay for assessing measles and rubella infection and immunity in outbreak settings in the Democratic Republic of the Congo.

The Democratic Republic of the Congo (DRC) has a high measles incidence despite elimination efforts and has yet to introduce rubella vaccine. We evaluated the performance of a prototype rapid digital microfluidics powered (DMF) enzyme-linked immunoassay (ELISA) assessing measles and rubella infection, by testing for immunoglobulin M (IgM), and immunity from natural infection or vaccine, by testing immunoglobulin G (IgG), in outbreak settings. Field evaluations were conducted during September 2017, in Kinshasa province, DRC. Blood specimens were collected during an outbreak investigation of suspected measles cases and tested for measles and rubella IgM and IgG using the DMF-ELISA in the field. Simultaneously, a household serosurvey for measles and rubella IgG was conducted in a recently confirmed measles outbreak area. DMF-ELISA results were compared with reference ELISA results tested at DRC's National Public Health Laboratory and the US Centers for Disease Control and Prevention. Of 157 suspected measles cases, rubella IgM was detected in 54% while measles IgM was detected in 13%. Measles IgG-positive cases were higher among vaccinated persons (87%) than unvaccinated persons (72%). In the recent measles outbreak area, measles IgG seroprevalence was 93% overall, while rubella seroprevalence was lower for children (77%) than women (98%). Compared with reference ELISA, DMF-ELISA sensitivity and specificity were 82% and 78% for measles IgG; 88% and 89% for measles IgM; 85% and 85% for rubella IgG; and 81% and 83% for rubella IgM, respectively. Rubella infection was detected in more than half of persons meeting the suspected measles case definition during a presumed measles outbreak, suggesting substantial unrecognized rubella incidence, and highlighting the need for rubella vaccine introduction into the national schedule. The performance of the DMF-ELISA suggested that this technology can be used to develop rapid diagnostic tests for measles and rubella.

Whole gene analysis of a genotype G29P[6] human rotavirus strain identified in Central African Republic.

OBJECTIVE: Rotavirus A (RVA) remains the main causative agent of gastroenteritis in young children and the young of many mammalian and avian species. In this study we describe a RVA strain detected from a 6-month-old child from Central African Republic (CAR). RESULTS: We report the 11 open reading frame sequences of a G29-P[6]-I2-R2-C2-M2-A2-N2-T2-E2-H2 rotavirus strain, RVA/Human-wt/CAR/CAR91/2014/G29P[6]. Nine genes (VP1-VP3, VP6, NSP1-NSP5) shared 90-100% sequence similarities with genogroup 2 rotaviruses. Phylogenetically, backbone genes, except for VP3 and NSP4 genes, were linked with cognate gene sequences of human DS-1-like genogroup 2, hence their genetic origin. The VP3 and NSP4 genes, clustered genetically with both human and animal strains, an indication genetic reassortment human and animal RVA strains has taken place. The VP7 gene shared nucleotide (93-94%) and amino acid (95.5-96.7%) identities with Kenyan and Belgian human G29 strains, as well as to buffalo G29 strain from South Africa, while the VP4 gene most closely resembled P[6]-lineage I strains from Africa and Bangladesh (97%).

Rapid diagnostic tests to address challenges for global measles surveillance.

Recently, a lateral flow rapid diagnostic test (RDT) with good accuracy has been described. This test enables measles specific IgM antibody detection in serum, capillary blood and oral fluid. RDTs have the potential to transform measles surveillance by allowing real-time case confirmation outside of central/regional laboratories and by facilitating a timely public health response. Measles virus genes can also be amplified and sequenced consistently from dried IgM-positive RDTs stored outside of cold chain, which will enable more complete virologic surveillance. Critical questions remain regarding operational use of RDTs as part of global measles surveillance. Projects to evaluate RDT use as part of national surveillance programs and to commercialize the RDT are underway.

Seroprevalence of rubella virus antibodies among pregnant women in the Center and South-West regions of Cameroon.

Rubella infection in early pregnancy can lead to miscarriages, fetal death, or birth of an infant with congenital rubella syndrome (CRS). In Cameroon, like in many developing countries, rubella surveillance is not well-established. The aim of this study was to determine the prevalence of rubella virus specific antibodies among pregnant Cameroonians. We conducted a cross-sectional study for rubella infection among pregnant women attending antenatal clinics in the Center and South-West regions of Cameroon. Demographic data and blood were collected and tested for rubella specific antibodies (IgG and IgM), and for the IgM positive cases, IgG avidity and real time PCR was done. From December 2015 to July 2017, 522 serum samples were collected and tested from pregnant women. The seroprevalence of rubella specific IgG was 94.4%, presumably due to immunity induced by wild-type rubella virus. The seroprevalence of rubella specific IgM was 5.0%, possibly indicating rubella infection. However, IgG avidity testing of the IgM positive cases detected high avidity IgGs, ranging from 52.37% to 87.70%, indicating past rubella infection. 5.6% (29/522) of the participants had negative results for IgG to rubella virus, indicating susceptibility to rubella infection. None of the participants had received a rubella containing vaccine (RCV), but 51% (266/522) of the pregnant women lived in a house with a child with records of at least one dose of RCV. Rubella virus RNA was not detected in the urine of any IgM positive case. Findings from this study show that rubella infection is significant in Cameroon. Some pregnant women are still susceptible to rubella infection. For a better management of rubella infection in pregnancy in Cameroon, consideration should be taken to investigate for IgG-avidity test in cases with positive rubella IgM result to distinguish between recent from past rubella infection.

Use of FTA Cards To Transport Throat Swabs and Oral Fluid Samples for Molecular Detection and Genotyping of Measles and Rubella Viruses.

The genetic characterization of measles viruses is an important tool for measles surveillance. Reverse cold chain requirements for the transportation of samples to reference laboratories are challenging in resource-limited settings. FTA cards facilitate the transport of virologic samples at ambient temperature as noninfectious material; however, the utility of FTA cards for the detection and genotyping of measles virus from clinical samples has not been evaluated. Throat swabs (TS) and oral fluid (OF) samples were collected from suspected measles cases in the Democratic Republic of the Congo. Virus detection (reverse transcription-quantitative real-time PCR [RT-qPCR]) and genotyping (endpoint RT-PCR) were compared for samples from 238 suspected cases; these samples were either transported using the reverse cold chain or at ambient temperature on FTA cards. Virus detection showed excellent positive agreement for OF samples compared to TS (95.3%; confidence interval [CI], 91.6 to 97.4), in contrast to 79.4% (CI, 73.5 to 84.3) for TS on FTA, and 85.5% (CI, 80.2 to 89.6) for OF on FTA compared to OF samples. Genotyping results obtained for a subset of samples indicated that 77.3% of all TS and 71.0% of OF samples would produce genotype information compared to 41.6% of TS and 41.3% of OF on FTA cards. Similar results were found for 16 measles-negative samples that were confirmed as rubella cases. Measles genotype B3 and rubella genotype 2B were detected. FTA cards have limited utility for virologic surveillance of sporadic cases of measles; however, they can be a useful tool for the expansion of virologic surveillance in countries where the reverse cold chain is not available.

Epidemiology of rubella infection and genotyping of rubella virus in Cote d'Ivoire, 2012-2016.

Rubella is a contagious disease caused by the rubella virus (RuV) that can lead to serious birth defects when women are infected in early pregnancy. This study aimed to describe the epidemiology and genetic diversity of rubella viruses in Cote d'Ivoire (CIV). Blood or oral fluid samples collected from suspected measles cases were first tested for the presence of measles specific IgM antibodies by enzyme-linked immunosorbent assay (ELISA). All measles IgM negative or indeterminate samples were tested for rubella IgM antibody using ELISA. Rubella-IgM-positive samples were tested by real-time reverse transcription polymerase chain reaction (RT-PCR) for the presence of rubella virus RNA. Real-time RT-PCR-positive RNA samples were used as template to amplify the 739 nt region used for rubella genotyping. PCR-positive samples were sequenced and phylogenetic analysis performed. Between 2012 and 2016, 4121 serums and 126 oral fluids were collected through the measles surveillance system. Of these, 3823 and 108 respectively were measles IgM negative or indeterminate. Subsequent testing for rubella found that 690 of 3823 (18%) serum samples and 25 of 108 (23%) oral fluid samples were rubella IgM-positive. The 739 nt segment of the E1 glycoprotein gene was amplified and sequenced for two serums and seven oral fluids samples. Phylogenetic analysis showed that the rubella viruses from CIV belonged to genotypes 1G (eight samples) and 2B (one sample). Rubella virus genotype 2B was found in CIV for the first time. These data contribute to baseline information on rubella virus strains found in CIV before the introduction of rubella vaccine.

Emergence of G12 and G9 rotavirus genotypes in the Central African Republic, January 2014 to February 2016.

OBJECTIVES: Rotavirus gastroenteritis is a major cause of death among children under 5 years globally. A rotavirus gastroenteritis surveillance program started in October 2011 in the Central African Republic (CAR) with the Surveillance Epidémiologique en Afrique Centrale (SURVAC) project. We present here genotyping results showing the emergence of G9 and G12 genotypes in Central African Republic. RESULTS: Among 222 children hospitalized with acute gastroenteritis who had a stool sample collected at the sentinel site, Complexe Pédiatrique de Bangui (CPB), Bangui, Central African Republic, 100 (45%) were positive for rotavirus between January 2014 and February 2016. During this period the most common rotavirus strains were G1P[8] (37%), G12P[6] (27%) and G9P[8] (18%).

Assessment of National Public Health and Reference Laboratory, Accra, Ghana, within Framework of Global Health Security.

The Second Year of Life project of the Global Health Security Agenda aims to improve immunization systems and strengthen measles and rubella surveillance, including building laboratory capacity. A new laboratory assessment tool was developed by the Centers for Disease Control and Prevention to assess the national laboratory in Ghana to improve molecular surveillance for measles and rubella. Results for the tool showed that the laboratory is well organized, has a good capacity for handling specimens, has a good biosafety system, and is proficient for diagnosis of measles and rubella by serologic analysis. However, there was little knowledge about molecular biology and virology activities (i.e., virus isolation on tissue culture was not available). Recommendations included training of technical personnel for molecular techniques and advocacy for funding for laboratory equipment, reagents, and supplies.

Pre-vaccine circulating group a rotavirus strains in under 5 years children with acute diarrhea during 1999-2013 in Cameroon.

The aim of this review was to assess all the studies on rotavirus G and P characterization during the pre-vaccine period (1999-2013) in Cameroon to have a better basis for post-vaccine introduction evaluations. A retrospective study was done through a comprehensive review of published (PubMed, Google Scholar) and accessible unpublished data on rotavirus G and P genotypes circulating in five regions of Cameroon. Descriptive data were expressed as frequencies tables and proportions. A total of 1844 rotavirus positive cases were analyzed. In all, 1534 strains were characterized for the P (VP4) specificity. Six different VP4 genotypes were observed, including P [4], P [6], P [8], P [9], P [10] and P [14]. The most predominant P genotypes were P [8] at 42.6%, and P [6] at 37.9%. Mixed infections were observed at 5.3%, whereas 4.1% of the strains were P non-typeable. A total of 1518 rotavirus strains were characterized for the G (VP7) specificity. VP7 genotypes G1, G2, G3, G4, G5, G6, G8, G9, G10 and G12 were observed. G1 (35.3%), G3 (19.5%), G2 (14.9%) and G12 (10.1%) were the predominant G genotypes while G5 and G10 were least prevalent at 0.06% each. Approximately 5.1% of all strains were G non-typeable whereas 5.3% were mixed G genotypes. A total of 1472 strains were characterized for both G and P genes, from which 38 different G-P combinations were observed. Overall, G1P [8] (22%) was identified as the predominant rotavirus strain circulating in Cameroon followed by G3P [6] (15%). In conclusion, we observed that the genotypes identified in Cameroon during 1999-2013 were partially covered by the two WHO recommended rotavirus vaccines. This review provides comprehensive up-to-date information on rotavirus strain surveillance in Cameroon during the pre-vaccination era.

Genotypes of rubella virus and the epidemiology of rubella infections in the Democratic Republic of the Congo, 2004-2013.

Rubella is a viral infection that may cause fetal death or congenital defects, known as congenital rubella syndrome (CRS), during early pregnancy. The World Health Organization (WHO) recommends that countries assess the burden of rubella and CRS, including the determination of genotypes of circulating viruses. The goal of this study was to identify the genotypes of rubella viruses in the Democratic Republic of the Congo (DRC). Serum or throat swab samples were collected through the measles surveillance system. Sera that tested negative for measles IgM antibody were tested for rubella IgM antibody. Serum collected within 4 days of rash onset and throat swabs were screened by real-time RT-PCR for rubella virus RNA. For positive samples, an amplicon of the E1 glycoprotein gene was amplified by RT-PCR and sequenced. 11733 sera were tested for rubella IgM and 2816 (24%) were positive; 145 (5%) were tested for the presence of rubella RNA by real-time RT-PCR and 10 (7%) were positive. Seventeen throat swabs were analyzed by RT-PCR and three were positive. Sequences were obtained from eight of the positive samples. Phylogenetic analysis showed that the DRC rubella viruses belonged to genotypes 1B, 1E, 1G, and 2B. This report provides the first information on the genotypes of rubella virus circulating in the DRC. These data contribute to a better understanding of rubella burden and the dynamics of rubella virus circulation in Africa. Efforts to establish rubella surveillance in the DRC are needed to support rubella elimination in Africa. J. Med. Virol. 88:1677-1684, 2016. © 2016 Wiley Periodicals, Inc.

Strengthening laboratory capacity through the surveillance of rotavirus gastroenteritis in Central Africa: the Surveillance Épidémiologique en Afrique Centrale (SURVAC) Project.

OBJECTIVES: The goal of the SURVAC pilot project was to strengthen disease surveillance and response in three countries; Cameroon (CAE), Democratic Republic of the Congo (DRC) and Central African Republic (CAR). METHODS: Seven laboratories involved in rotavirus surveillance were provided with equipment, reagents and supplies. CDC and WHO staff provided on-site classroom and bench training in biosafety, quality assurance, quality control (QC), rotavirus diagnosis using Enzyme Immunoassay (EIA) and genotyping of rotavirus strains using the Reverse Transcription Polymerase-chain reaction (RT-PCR). All laboratory data were reported through WHO/AFRO. RESULTS: Twenty-three staff members were trained on RT-PCR for rotavirus genotyping which was introduced for the first time in all three countries. In CAE, the number of samples analysed by EIA and RT-PCR increased tenfold between 2007 and 2013. In DRC, this number increased fivefold, from 2009 to 2013 whereas in CAR, it increased fourfold between 2011 and 2013. All laboratories passed WHO proficiency testing in 2014. CONCLUSION: Laboratory capacity was strengthened through equipping laboratories and strengthening a subregional laboratory workforce for surveillance of rotavirus gastroenteritis. Each of the three countries generated rotavirus surveillance and genotyping data enabling the mapping of circulating genotypes. These results will help monitor the impact of rotavirus vaccination in these countries.

Molecular surveillance of rotavirus infection in Bangui, Central African Republic, October 2011-September 2013.

BACKGROUND: The World Health Organization (WHO) recommends the introduction of rotavirus vaccine in the immunization program of all countries. In the Central African Republic (CAR), sentinel surveillance for rotavirus gastroenteritis was established in 2011 by the Ministry of Health, with the support of the Surveillance en Afrique Centrale Project (SURVAC). The purpose of this study was to assess the burden of rotavirus gastroenteritis and to identify rotavirus strains circulating in CAR before the introduction of rotavirus vaccine planned for this year, 2014. METHODS: One sentinel site and one laboratory at the national level were designated by the CAR Ministry of Health to participate in this surveillance system. Stool samples were collected from children who met the WHO rotavirus gastroenteritis case definition (WHO, 2006). The samples were first screened for group A rotavirus antigen by enzyme immunoassay (EIA), and genotyping assays performed using a multiplex reverse transcriptase PCR (RT-PCR) technique. RESULTS: Between October 2011 and September 2013, 438 stool samples were collected and analyzed for detection of rotavirus antigen; 206 (47%) were positive. Among the 160 (78%) that could be genotyped, G2P[6] was the predominant strain (47%) followed by G1P[8] (25%) and G2P[4] (13%). CONCLUSIONS: Almost half of stool samples obtained from children hospitalized with gastroenteritis were positive for rotavirus. These baseline rotavirus surveillance data will be useful to health authorities considering rotavirus vaccine introduction and for evaluating the efficacy of rotavirus vaccine once it is introduced into the routine immunization system.

Molecular surveillance of rotavirus strains circulating in Yaoundé, Cameroon, September 2007-December 2012.

Rotavirus is the most common cause of severe diarrheal disease in children under 5 years of age worldwide. The World Health Organization (WHO) estimated that 453,000 rotavirus-attributable deaths occur annually. Through the WHO, the Rotavirus Sentinel Surveillance Program was established in Cameroon in September 2007 with the Mother and Child Center (MCC) in Yaoundé playing the role of sentinel site and national laboratory for this program. The objectives of this surveillance were to assess the rotavirus disease burden and collect baseline information on rotavirus strains circulating in Cameroon. Diarrheal stool samples were collected in a pediatric hospital from children under 5, using the WHO case definition for rotavirus diarrhea. Antigen detection of rotavirus was performed by using an enzyme immunoassay (EIA). The genotypic characterization was performed using multiplexed semi-nested reverse transcription-polymerase chain reaction (RT-PCR) assays. Between September 2007 and December 2012, 2444 stool samples were received at the MCC laboratory for rotavirus antigen detection, of which 999 (41%) were EIA positive. Among EIA positive samples 898 were genotyped. Genotype prevalence varied each year. Genotype G9P[8] was the dominant type during 2007 (32%) and 2008 (24%), genotype G3P[6] predominated in 2010 (36%) and 2011 (25%), and G1P[8] was predominant in 2012 (44%). The findings showed that the rotavirus disease burden is high and there is a broad range of rotavirus strains circulating in Yaoundé. These data will help measure the impact of vaccination in the future.

Molecular surveillance of rotavirus infection in the Democratic Republic of the Congo August 2009 to June 2012.

BACKGROUND: Rotavirus is a major cause of severe diarrhea worldwide. It causes 453,000 deaths in children annually. In the Democratic Republic of the Congo, sentinel site surveillance of rotavirus gastroenteritis started in 2009 and aimed to document burden of rotavirus diarrhea and identify circulating rotavirus genotypes. METHODS: Between August 2009 to June 2012, stool samples were collected in Kinshasa and Lubumbashi, from children <5 years of age who met the WHO case definition for rotavirus gastroenteritis. Rotavirus antigen detection was performed using an enzyme immunoassay technique and rotavirus strains were characterized using a multiplex reverse transcription polymerase chain reaction assay. RESULTS: During the study period, 1614 stool samples were screened for rotavirus by enzyme immunoassay and 990 (61%) were positive. Of these, the genotype was determined in 330 (33%) samples. The most common genotypes found in the samples analyzed were G1P[8] in 2009 (28%) and 2012 (33%), G2P[4] (33%) in 2010 and G2P[6] (28%) in 2011. Uncommon strains like G8P[6] (5%), G6P[6] (5%), G12P[6] (3%), G12P[8] (3%) and G8P[8] (2%) were also detected. CONCLUSIONS: In Democratic Republic of the Congo, 61% of the diarrhea in children in <5 years of age was caused by rotavirus infection and a variety of rotavirus genotypes were detected. Implementation of rotavirus genotyping at the national level has improved the timely identification of rotavirus strains. These results will help decision makers in Democratic Republic of the Congo plan the implementation of a rotavirus vaccination program.

Molecular characterization of measles virus strains causing subacute sclerosing panencephalitis in France in 1977 and 2007.

Measles virus strains from two subacute sclerosing panencephalitis (SSPE) cases diagnosed in 1977 (Laine strain) and in 2007 (Hoedts strain) were studied. Phylogenetic analysis based on C-terminal part of the nucleoprotein and the entire H gene showed that Hoedts strain, circulating in France presumably in the 1980s, belonged to genotype C2. However, Laine strain, suspected to have circulated between 1940s and 1960s, could not be assigned to any known measles virus genotypes. Sequences analysis of the Laine strain suggested that it originated from a measles virus that may have circulating at the same period as the Edmonston strain. The analysis of the whole genome of both SSPE strains revealed biased hypermutations in M, F, and H gene. Some of these mutations like the L165P found in the M protein sequence of the Laine strain, the amino acid position 94, where a mutation M94V was found in the F protein sequence of the Hoedts strain are known to play an important role in the glycoprotein interaction and to impair the ability of measles virus strain to produce cell-free infectious viral particles.This is the first study on molecular characterization of the entire coding region of measles virus isolated from SSPE cases in France.

[Measles and its virus]. / La rougeole et son virus.

After the huge decrease of measles thanks to vaccination, measles reappeared in 2008, with 604 cases reported at the Institut national de veille sanitaire (InVS), then 1,544 cases in 2009 and 2,605 cases up to 2010, June. At the same time, 86 viral strains were detected from saliva samples at the Centre national de référence de la rougeole et des Paramyxoviridae respiratoires (CNR) in 2008, 316 in 2009 and 946 up to August 2010. The reality of the outbreak was confirmed by the increase of the endemic cases: 0.0009% cases in 2008 and 0.004% in 2010, the diffusion to all parts of France, and the more specific attack of infants: 4% in 2008 and 9% in 2010, and of young adults: 17% in 2008 and 38% in 2010. Most of the cases (82%) occurred in non-vaccinated people. The number of hospitalised cases has increased as well, going from 18% in 2008 to 34% in 2010. The strain of this outbreak is a genotype D4. It appeared in 2008 then it spread in 2009 and 2010, representing 19, 75 and 99% of the strains, respectively. All the viruses in this genotype belonged to the Montreal-like cluster described in 1989: Montréal.CAN/89xD4. At the beginning of the outbreak some were closed to a variant which appeared in England in 2007 MVs/Enfield.GBR/14.07(D4), but most of them (95%) are nowidentical to a strain which caused a small focus of measles in the region Vendee at the last trimester 2008: MVs/Montaigu.FRA/43.08(D4). The salivary diagnosis of measles, which was introduced in France in 2005, in parallel to the obligation of reporting measles cases, has been proved very efficient: 75% of saliva are collected in the first four days, and viral RNA was detected in 536 (81%) out the 660 samples received at the CNR up to now in 2010; 136 (21%) saliva had IgM specific antibodies and 18% had neither RNA, nor IgM.

Co-circulation of multiple measles virus genotypes during an epidemic in France in 2008.

In 2008, measles reappeared in France in a series of outbreaks. During this period, 604 measles cases were reported to a routine surveillance system and 305 (50%) of these cases were then confirmed in the laboratory. To understand better the current epidemiological situation and the circulation of different measles strains, a phylogenetic characterization of 113 (19%) of the measles cases from these outbreaks was performed. All measles cases met the WHO clinical criteria and were confirmed either by laboratory detection of measles-specific IgM and/or by detection of the virus genome by polymerase chain reaction (PCR) and viral isolation. PCR products generated from blood, oral fluid, urine, or nasopharyngeal-swab samples were sequenced for molecular epidemiology studies. Phylogenetic analysis showed a co-circulation of genotypes D4 and D5 during the first measles outbreak in the city of Reims in early 2008. Over the course of the year, the A, B3.2, D8, and D9 genotypes also appeared. The data from this study show the simultaneous circulation of several measles genotypes in France and describe genotypes D8 and D9 for the first time in this country. The data also suggest that there are still many pockets of unvaccinated individuals helping to maintain the circulation of measles virus in the population. Phylogenetic studies allowed the corroboration of epidemiologic links and showed that nosocomial transmission can create significant risk for measles dissemination. Finally, the pattern of changes in viral genotypes during 2008 suggests a regular introduction of measles strains from abroad.

Wild type measles virus attenuation independent of type I IFN.

BACKGROUND: Measles virus attenuation has been historically performed by adaptation to cell culture. The current dogma is that attenuated virus strains induce more type I IFN and are more resistant to IFN-induced protection than wild type (wt). RESULTS: The adaptation of a measles virus isolate (G954-PBL) by 13 passages in Vero cells induced a strong attenuation of this strain in vivo. The adapted virus (G954-V13) differs from its parental strain by only 5 amino acids (4 in P/V/C and 1 in the M gene). While a vaccine strain, Edmonston Zagreb, could replicate equally well in various primate cells, both G954 strains exhibited restriction to the specific cell type used initially for their propagation. Surprisingly, we observed that both G954 strains induced type I IFN, the wt strain inducing even more than the attenuated ones, particularly in human plasmacytoid Dendritic Cells. Type I IFN-induced protection from the infection of both G954 strains depended on the cell type analyzed, being less efficient in the cells used to grow the viral strain. CONCLUSION: Thus, mutations in M and P/V/C proteins can critically affect MV pathogenicity, cellular tropism and lead to virus attenuation without interfering with the alpha/beta IFN system.

High genetic diversity of measles virus, World Health Organization European Region, 2005-2006.

During 2005-2006, nine measles virus (MV) genotypes were identified throughout the World Health Organization European Region. All major epidemics were associated with genotypes D4, D6, and B3. Other genotypes (B2, D5, D8, D9, G2, and H1) were only found in limited numbers of cases after importation from other continents. The genetic diversity of endemic D6 strains was low; genotypes C2 and D7, circulating in Europe until recent years, were no longer identified. The transmission chains of several indigenous MV strains may thus have been interrupted by enhanced vaccination. However, multiple importations from Africa and Asia and virus introduction into highly mobile and unvaccinated communities caused a massive spread of D4 and B3 strains throughout much of the region. Thus, despite the reduction of endemic MV circulation, importation of MV from other continents caused prolonged circulation and large outbreaks after their introduction into unvaccinated and highly mobile communities.