The Clinical And Molecular Epidemiological Characteristics Of Measles In Children Since The Initiation Of The Immunization Program

Objective:Analyze the clinical data and molecular epidemiological characteristics of children with measles in Shanghai to identify the measles' clinical characteristics in children and the prevalent genotype of measles virus;Evaluate the level of measles' IgG in healthy lying-in mothers and non-measles infants to assess their protective competence to measles.Methods:We analyzed and summarized 355 hospitalized children between July 2007 and June 2008 in our hospital to demonstrate the crowds,ages of onset of measles and other epidemiological data;To diagnose measles early and quickly we collected 45 throat swabs specimen and urine samples each of measles children in acute stage out of these 355 children and detected some genes of measles viruses with reverse transcriptase-polymerase chain reaction(RT—PCR);Out of the 355 children,28 throat swabs specimen within 3 days of the onset of rashes were collected and were sent to Center for Disease Control and prevention(CDC) of Shanghai to isolate measles viruses,and then the genotypes of the isolated viruses were determined subsequently in CDC of China to identify the prevalent genotype.We collected blood samples from 100 healthy lying-in mothers and applied Enzyme Linked ImmunoSorbent Assay(ELISA) to detect the levels of MV IgG.We collected blood samples from 52 non-measles newborns and applied ELISA to detect the levels of MV IgG.We also collected blood samples from 52 non-measles infants younger than 6 months old and applied ELISA to detect the levels of MV IgG.Results:There was no fixed season of measles' onset.This data illustrated that most patients got sick in March,April,August and September.The immigrants occupied a bigger ratio than the native citizen, which was 1.93:1.The measles' crowds were inclined to be younger. Among this group the youngest was 22 days old and the oldest was 7 years and 9 months old,in which the ones younger than 9 months were the biggest part with a big ratio of 71.83%.The inoculation rate was only 24%.There were 45 patients,who took a percentage of 12.68%,had been definitely infected by others,but a lot of the others had a long history of receiving clinical services.The typical clinical features of measles were fever,rashes,cough and catarrh.The time span of fever-rash in 267 cases, who took a percentage of 75.21%,was 2-4 days and we could see Koplik spots in oral cavity within 3 days of rashes.249 cases got bronchopneumonia,which was the most common complication of measles,and they took a percentage of 70.14%.15 patients,who took a percentage of 4.23%,experienced abnormality of liver function.9 out of 15 children had low-grade abnormality and 6 of them got overt abnormal liver function.239 children got elevated CK-MB and 51 of them were diagnosed as myocardial damage because of overt CK-MB and/or abnormal electrocardiogram.4 out of 5 dead cases were dead of severe pneumonia.122 patients,who took a percentage of 41.78%,co-infected with bacteria,mycoplasma,Chlamydia or even with fungus.The most 3 common bacteria were Streptococcus pneumoniae,hemophilies influenzae and Haemophilus parainfluenzae.There were 38 out of 45 throat swabs specimen got positive results, which took a percentage of 84.4%.To speak of the urine samples,there were 6 positive results out of 45 cases,and the percentage was 13.3%. There were only 4 positive results in both throat swabs specimen and urine samples.Among these 28 children we also collected throat swabs and sent them to Center for Disease Control and prevention(CDC) of Shanghai to isolate measles virus which was operated by CDC completely.Except for one case which could not be isolated because of contamination,there were 17 out of 27 positive results,which took a percentage of 62.96%.The genotype of all analyzed measles viruses belonged to H1a.47 out of the 100(47%) healthy lying-in mothers had protective competence,which were more than 800 mIU/ml and only 9 of them(9%) had the obvious protective competence,which were more than 3200mIU/ml to prevent them from infecting measles virus.There were 20(38.46%) and 6(11.54%) cases respectively had protective competence,which were more than 800 mIU/ml and only 5 of the newborns(9.61%) had the obvious protective competence,which were more than 3200mIU/ml to prevent them from infecting measles virus.Conclusions:There was no fixed season of measles' onset.The immigrants occupied a bigger ratio than the native citizen,which was 1.93:1.The measles' crowds were inclined to be younger.The inoculation rate was 24%.The typical clinical features of measles were fever,rashes, cough and catarrh.The most complication of measles was bronchopneumonia.Most patients co-infected with bacteria,mycoplasma, Chlamydia or even with fungus.We used RT-PCR to identify measles early and it could make up the shortage of IgM.The results of genotypes stated that the prevalent strain of measles was still H1a,which was the same as that all over the country.The protective competence was low in lying-in mothers:47%of them could protect them from symptomatic infection of measles and only 9%of them could produce a marked effect in resisting measles.To speak of infants who were not inoculated,the protective competence was low,too.38.46%of the newborns could protect them from symptomatic infection of measles and only 9%of them could produce a marked effect in resisting measles.The protective antibodies decreased gradually with they grew up and the percentage of prevention dropped to 11.54%,and the capability to produce a marked effect in resisting measles vanished finally.