Influenza or flu, acute(extremo,
agudo), highly(altamente)
contagious disease(enfermedad)
caused by any one of at least(al
menos) three types of virus, but usually by types designated A
and B. Formerly(antiguamente)
known as the grippe, influenza is difficult to diagnose(diagnosticar)
in the absence of an epidemic(epidemia),
since it resembles(se
parece a) many common respiratory ailments(achaques,
dolencias). It can be distinguished from a cold(resfriado),
however, by sudden fever(fiebre
repentina), prostration(postración,
abatimiento), weakness(debilidad),
and sometimes severe muscular aches and pains(achaques
y dolores). It is spread(extendida,
difundida) by respiratory droplets(gotitas).
Influenza is usually self-limiting(limitada
en efectos), but complications such as pneumonia and bronchitis
can be serious threats(amenazas)
to newborns(recién
nacidos), the elderly(tercera
edad), and people with chronic diseases(enfermedades
crónicas). Epidemics of influenza (usually of type A),
sometimes worldwide(en
todo el mundo) in scope(alcance),
have decimated(diezmado)
large populations (more than 20 million people in 1918). Type B is more
likely to occur sporadically.
Because a number of different viral strains(variedades)
can cause the disease, immunity to one type does not prevent susceptibility
to another. Influenza virus vaccine(vacuna)
confers(concede)
immunity to a particular strain and is recommended for persons at risk;
unfortunately the surface(superficie)
antigens of flu viruses change periodically, making it necessary to
reformulate the vaccine yearly in an educated guess(suposición,
conjetura) at what strain will appear.
The antiviral drugs amantadine and rimantadine are effective against type A
influenza, and zanamivir against types A and B. Treatment with antibiotics
has greatly(ampliamente)
reduced fatalities(víctimas
mortales) from secondary infections. Uncomplicated(sencilla)
influenza requires only rest(descanso)
and treatment of symptoms(síntomas).
Return to normal activity should be undertaken(llevada,
emprendida) slowly, as relapses(recaídas)
are easily precipitated.
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