Outbreak of measles in France in 2008

In Encyclopedia by Manon Alexandre Views: 3

Worldwide, there are more than 30 million children infected by the virus of measles, one of the most communicable infectious diseases. In Quebec, since the implementation of vaccination campaigns against measles in the 1960s, the incidence of this disease has decreased so that there are, to date, only one or two cases per year. In France, the (binding) administration of MMR (against measles, mumps and rubella) vaccine is strongly recommended in young children, the upsurge in the number of cases of measles in this country in recent years reflects important among other the refusal of the population to be vaccinated and authenticates, in 2008, the outbreak of an epidemic.

General

Measles is a highly contagious viral disease caused by a virus RNA negative polarity, of the family Paramyxoviridae and the kind of the Morbilivirus. The highly infectious virus is spread by droplets suspended in the air and infects immune cells of the pharynx and lungs via the attachment of its surface (hemagglutinin) to specific cell receptors proteins. The most common symptoms of measles include high fever, a cough, nasal discharge, the appearance of redness on the body, eye pain and watery eyes when light charge. In France, from 1945 to 1986, measles was part of diseases notifiable, i.e. that found cases in care centres, by doctors or hospital staff should be reported for the purposes of analysis and monitoring. Given the low amount of cases listed, this status was suspended in 1986 and replaced by a sentinel of general practitioners, the Sentinel network, created in 1985 by the INSERM U444, to electronically report cases of measles that they have witnessed in consultation. The incidence of the disease inferred from these data suggests a decrease of 300,000 cases per year in 1985 to about 10,400 cases in 2003 and 4448 cases in 2004. Since July 2005, the national plan of eradication of the disease, the Declaration of measles is again required.

French economy

Prevention and elimination

Placed on the market in 1966 in France, the measles vaccine was added to the immunization schedule for children from 12 to 15 months than in 1983. In 1986, was offered to protect against measles, mumps and rubella MMR vaccine. Ten years later, a second dose was prescribed (in the children of 11 to 13 years old at the time; those 6 years now) to increase the efficiency of vaccination for the Elimination of the disease. A plan for the Elimination of measles and congenital rubella syndrome in France (Plan for measles and congenital rubella elimination in France) was published in June 2005. These general objectives concerning the measles include the judgment of endemic transmission of the virus of measles and the achievement and maintenance of a high level of immunity in the population via vaccination. More specifically, it is achieving a lower incidence in a case confirmed by million inhabitants and the reduction in the percentage of vulnerable people to the virus under the 15% for children 1-4 years, 10% for children of 5 to 9 years, and under 5% for adults over 15 years. The authorities want an immunization coverage of more than 95% for toddlers 24 months and 80% for the second dose. The ultimate objective of response plan is the Elimination of the virus of the national territory for 2010. The measures described in the plan included, among others, a new vaccine strategy involving a new vaccination schedule, a better awareness and dissemination of information on population, the identification and protection of the groups most at risk (travellers, the health professionals, the entourage of an infected person or an outbreak of infection…) and a new monitoring strategy including criteria for clinical diagnosis and laboratory confirmation. One of the major obstacles in the Elimination of the disease lies in the reluctant groups for vaccination for philosophical or religious reasons, or the low immunization coverage is due to the difficult geographical and financial accessibility to vaccination. It should be noted that in France, however, there are no financial barriers or geographical as private and public networks ensure to make optimal access to vaccination against measles. In France, although vaccination has reduced encouragingly the incidence of disease and mortality associated, there is that the coverage of immunization (of approximately 85%, with disparities depending on the departments) does not the judgment of the transmission and the Elimination of measles. The circulation of the virus, although that reduced, remains sufficient to cause outbreak of infection which can cause an epidemic. Individuals, non-vaccinated and non-immunized by the wild type virus because less subject to exposure because of reduced circulation, are easy prey and ideals initiators of epidemic.

Epidemic

The refusal of the population to vaccination against measles in European countries does not achieve optimal immunization coverage of 95% such that desired by the world Organization of the health (who) to eradicate the disease. On the contrary, despite a plan for the Elimination of measles, there a resurgence of the disease in several countries, including the Switzerland, the Romania, the England and the France. In France, it is in spring 2008 that the number of monthly cases has begun to increase. Late spring and summer, there is grouped cases of measles among children and adolescents attending denominational schools or in camps of vacation bringing together young people from these schools. There is family important secondary transmissions and a marked increase in cases in the fall, after the re-entry of classes. In fact, nearly two thirds of the statements occurred between October and December 2008. Compared to 40 cases in 2006 and 44 in 2007, there were, in 2008, 604 selected cases of measles among 620 suspected cases including 305 confirmed biologically (by the detection of serum IgM, viral RNA, by highlighting of seroconversion in IgG) or detection of salivary IgM to the national reference (RSS) Centre of measles and respiratory paramyxoviridea58 epidemiologically confirmed cases and 241 clinical cases.

Characterization of the epidemic

Geographical and epidemiological distribution

The geographic distribution of the reported cases was not uniform. The first outbreak took place towards the end of March, Reim, in the northeast of the France, where 19 cases have been reported. Between March and may, it denotes a second outbreak in Nice, in the southeast of the country: 36 listed cases, of which 33 were biologically confirmed. From May to July, 105 cases of measles sign the third outbreak of measles in the regions of Burgundy and France. From the month of August, cases have been listed from different regions. Some departments of the France have not been affected by the epidemic, while in the Vendée, Deux-Sèvres, the Allier, Haute-Savoie and Savoie were found to impact five times higher than the national figure. Certain classes of age were far more cases than others. The average age of the patients was 12.7 years and median age 11.5 years. The rate of incidence among children 14 years and less varied between 3.2 and 3.6/100,000 while it decreased among older people. There was the the higher proportions of cases among adults over 30 years, the 20-29 age and children less of 1 year. 1 H/F of the reported ratio indicated that the disease did not preferentially affect men or women. Among the hospitalized cases (19%), the majority concerned adults aged between 20 and 29 years (59%) and 30 years and more (36%). About 89% of infected individuals had not been vaccinated against measles, 9% had received only one dose of the vaccine, and 2% had received two doses. The reported cases could present fever, maculo-papular eruptions, cough, a coryza (runny nose and repeated sneezing), conjunctivitis and signs of Koplik (harbinger of measles, presence of red spots in the White Center on the inside of the cheeks) to varying degrees.

Determination of infection

In General, when a case of measles is suspected, the doctor takes samples of saliva in the patient (ideally the 2nd or 3rd day of the eruption) and sends them to NRC where attempts to detect the presence of IgM and IgG anti-virus of the measles. While traditionally we realize rather a search of immunoglobulin in the blood of patients, serology from saliva samples is a more simple way while remaining effective. Observed that in 2008 and 2009 the physicians perform more often salivary samples than before. NRC, researchers also conduct research of viral RNA by RT – PCR in the collected saliva. This method is much more sensitive to confirm infection with the measles virus from a saliva sample as the detection of IgM and IgG in saliva: salivary serology does detect the presence of antibodies in 79.5% of the 137 biologically confirmed samples (presence of viral RNA and IgM against the measles virus), while in 93.4% of cases are detected viral RNA by RT – PCR.

Virology of the epidemic

The study of virus strains detected since the beginning of the epidemic showed the simultaneous movement of many different genotypes. Analysis reported in the Journal of Medical Virology in 2010 indicated the presence, in France, genotypes A, B3.2, D4, D5, D8 and D9. Interestingly, D8 and D9 genotypes not were ever detected. These results are based on genetic analysis of the regions C-terminal of the gene of nucleoprotein (N) from 113 strains and the whole of the hemagglutin (H) gene, in comparison to the analysis of strains detected in 2007. The cases listed during the first outbreak of measles in March 2008 to Reim, are due to the variant 1 virus genotype D4, with one exception caused by the D5 genotype. Spreading then in other regions, D5 and D4 genotypes have been responsible for 70% and 20.3% of the infections, respectively. During the second outbreak, the patient “index”, that is the initiator of the epidemic, income of Thailand where he contracted the virus of measles of D9 genotype, infected his brother which in turn transmitted the virus to his doctor. Disease is so widespread among medical personnel and patients in the hospital. One exception isolated in Paris, all cases of MV genotype D9 (measles virus) were found in the region of Nice. The patient “index” of the third outbreak had contracted the disease during a trip to Switzerland and Austria. Subsequent outbreaks have been attributed to the variant genotype D5 1. The MV genotype D5 continued was started in France throughout the following year. The D8 genotype caused 10.7% of cases between the 42nd and 46th weeks in the region surrounding the city of mills. The 12th week, listed a few rare virus genotype B3.2, and genotype A between weeks 14 and 16.

Discussion

Despite a plan built to eliminate the disease, the French population could avoid the outbreak in 2008. Be it due to the non-strict application of the response plan, gaps in sanitary measures of hospitals, or the resistance of the population to adhere to the methods of prevention, still is to ask if the eradication of a disease, and widespread across the globe for centuries, is utopian. Although some have reservations as to the effectiveness and usefulness of vaccination, others argue that the solution may lie in prevention through immunization and the achievement of optimal coverage close to 95% could halt the spread of the virus to the point of stifling new epidemics. None of this is acquired, however, when still means vaccination opponents claim that it is an object of conspiracy and a violation of the rights of the person…