Flu & Paraflu

The symptoms seemed to extend from coast to coast--sore throat, a cough, runny nose, varying degrees of fever--and there were sensationalized press reports of a "deadly threat to the elderly'' and a "nationwide epidemic."

Thousands of Americans, mostly in the Eastern states, were down last week with something loosely described as flu. The U.S. Public Health Service, on guard against a new epidemic of the Asian flu, which first appeared in 1957, renewed its standard warning to groups of vulnerable people--pregnant women, patients who already have heart or lung disease, and the elderly--to get flu shots. Among children, much of the illness was of an old type, though one so recently distinguished from other diseases by medical scientists that it is not yet listed in the standard medical texts or dictionaries: parainfluenza. The same disease is also suspected in some adult illnesses.

Spotty by Cities. The geographic spottiness of the outbreaks confused public health authorities, and laboratory workers had the tedious job of identifying submicroscopic viruses in the laboratory to decide which of them were responsible for a particular patient's illness. The Asian A-2 strain of influenza virus has been identified in enough cases to convict it as the chief culprit in North Carolina's heavy outbreak of flu in January. The virus apparently spread to adjacent Virginia and South Carolina, and the University of Georgia had a local incident. Farther west, there were confirmed outbreaks at Great Lakes Naval Training Center in Illinois, at the University of Michigan, and in Kansas.

Maryland has had heavy absenteeism in schools and colleges; more than 300 of Baltimore's 3,740 policemen did not show up for duty. But Philadelphia, only 100 miles away, seemed to have nothing worse than the usual winter run of colds and grippe, with negligible absenteeism and no known cases of Asian flu.

In New York City, thousands of adults complained of flu--some of them rightly so, said the city health department after the presence of Asian virus had been confirmed. More than 100 children in one institution were affected. Predictably, some patients, who were already weak when the flu struck them down, contracted a second (bacterial) infection and pneumonia. As a result, the city's death rate rose, but not nearly as much as it had in the flu epidemics of 1957-58 and 1960.

Partial Immunity. Most alarming to many doctors was a New York City outbreak of bronchiolitis and viral pneumonia among children. Some hospitals reported them twice as prevalent as ever before. And for this the Asian A-2 virus was not to blame. In many cases, the guilty microbe was one of the parainfluenza viruses.

There are three such viruses, distinguished by numbers.* Parainfluenza 1 was first called Sendai virus, after the Japanese city where it was originally isolated. It is close enough kin to the true flu viruses to have once been called influenza D. It has now been found around the world. At one time or another, nearly every child in the U.S. gets infected with paraflu 1, and the illness is most likely to be severe in the very young. The resulting antibody may last a lifetime, but gives only partial immunity: an adult can be reinfected with the same virus, though he may get nothing worse than a cold.

Parainfluenza 2 is one of the common causes of croup in children. Whether it can reinfect them or attack adults is not yet known. Parainfluenza 3 behaves much like type 1. But all these viruses are so new to science that medical researchers still do not know such important details as the differences in their incubation periods after they infect a victim. New York City's concurrent outbreaks of flu and paraflu may provide some useful clues. Pediatricians have noted that parents tend to come down with a moderately severe illness about six days after a child gets sick.

*Medical scientists themselves have added to the confusion with an overlap of names. In 1892 a German researcher thought the cause of influenza was a bacillus, and named it Haemophilus influenzae. That bacillus is now known to cause infections in some flu victims, but only coincidentally. In 1922 a related bacillus, found in the throats of both cats and man, was named Haemophilus parainfluenzae, but has nothing to do with diseases now known to be caused by viruses.

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