时间:2019-01-13 作者:英语课 分类:VOA标准英语2011年(十二月)


英语课

Dengue Severity Depends on Prior Infection, Genetic 1 Variation


 


American and Nicaraguan scientists have discovered the reason why a second infection with dengue can often be much more serious, even fatal, than the first.



Dengue is a viral disease spread by mosquitoes. The World Health Organization estimates there may be 50 million infections worldwide every year.



In some cases it causes only a mild fever. In others, the virus can cause a potentially fatal complication called dengue hemorrhagic fever.



Why some cases are mild and others are severe has been something of a mystery that scientists in the U.S. and Nicaragua have now unraveled.



There are four major varieties, or "serotypes" of dengue, and lots of genetic variation within each serotype. Also, in areas where dengue is endemic, people are often infected more than once. The first infection may result in only mild symptoms, and the body produces antibodies that will protect against the particular variety that infected them.



"Those antibodies don't necessarily work against another version of the virus, and those antibodies actually help the other version of the virus to infect the cells that it wants to infect," explained researcher Matthew Henn, of the Broad Institute in Cambridge, Massachusetts.









Scientists have unraveled the mystery of why some cases of dengue are mild while others are severe.




He said that severe symptoms are more likely when a dengue infection of a particular sub-variety meets a victim whose previous exposure to a different dengue virus has produced a particular set of antibodies.



"And if you have a certain combination of that, you're more prone 2 to get severe forms of the disease."



Henn says the findings of his study have implications for the so-far unsuccessful efforts to develop a dengue vaccine 3. For example, the vaccine may have to be modified to account for subtypes of the virus that dominate in a particular area.



"There's a good chance that any kind of vaccine that we design for dengue is really going to have to be fine-tuned to the local setting that it may need to be used in."



adj.遗传的,遗传学的
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
adj.(to)易于…的,很可能…的;俯卧的
  • Some people are prone to jump to hasty conclusions.有些人往往作出轻率的结论。
  • He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。
n.牛痘苗,疫苗;adj.牛痘的,疫苗的
  • The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
  • She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。
学英语单词
3-cholestanone
adenosine monophosphates
Aghiresu
anti-beauty quark
artesian well pump
assignment control number
axiom of parallels
Braxton-Hicks contraction
Browning's phenomenon
Burghley House
buried hildfast
center feeding
Coldbackie
condensational waves
constructive confrontation
current operating performance income statement
Customs Cooperation Council
cystine stone
damosel, damozel
decomposition agent
deflection winding
Dendrobium longicornu
departable
electromagnetostriction
emotion control
fractional monetary units
French horns
funible
glycolaldehydes
Harrington's solution
Hejce
high resolution visible
homosexual conduct
human contact
Hypalon
innubilous
interventions
ionization erosion
ISCOMS
Laprugne
leggett
lob along
lower-energy coast
lysogenic viruses
machilidaes
Magnolia fulva
maintenance mores
medianoscopy
Meier Helmbrecht
mesantoins
Meymeh
myostromin
myotonic muscular dystrophy
narrators
need of growth
news-wall
non-clients
non-system mark time request
ossa japonicum
patro-
pelecanine
Pentecostal Fellowship of North America
Pharmacochalzite
physical educations
pilot-actuated safety valve
poor maintenance of equipment
POS data
pressing powder
pressure, gauge
prostaglandin(s)
radio antenna truck
return chute
rosegolds
sclerotizations
shift driven shaft
short-half-life material
single office exchange
smilacaceous
smooth sequence
snow-slide
soft-touch control
sojo
spasmodized
strength freeboard
strikethrough
Styrax suberifolius
subpixel
succedaneously
tack welding
telecentric light
tension magnet
terminal artery
Time is up
tindered
transfer price
twenty-nines
unmodifiable
uredo microstegii
utilitarianise
vietnam block
vulgarness
zall