The Deadliest Fall

By Larry Baum

An introduction to influenza was published in the previous issue.

A bout of the flu can be mild. In young, healthy adults, many infections pass unnoticed. But sometimes the influenza virus evolves into a strain that decimates its victims. The worst known strain swept the world in the Fall of 1918, infecting 500-1000 million and killing 40-100 million, about 2-5% of people.

There are several theories about where the pandemic began, but the likeliest origin was in Haskell County, Kansas, in the United States. People in the sparsely populated county, where farmers raised pigs, poultry, cattle, and grain, began suffering from influenza in late January 1918. Unusually for flu, it was young, healthy adults who were hardest hit. Victims fell ill suddenly, many progressing to pneumonia and dying, often within days. Within weeks, however, the epidemic ended. The natural geographic isolation of this community normally might have contained the fatal flu in a sort of unintentional quarantine, but the First World War intervened. Men were uprooted from their home towns and congregated in huge numbers in army camps for training and then shipping out to other camps or to fight in Europe. The destination for men from Haskell County was Camp Funston, part of Fort Riley, Kansas, where the first influenza case was reported in early March. As soldiers moved among camps, the virus spread. Within two months, the epidemic spread to most of the army camps and most of the largest cities in the United States. As American soldiers went to France, so did the virus, spreading first from the port of Brest.

The flu then spread worldwide. The pandemic reached its height in the Fall of 1918. Spain was affected early, and because Spain was not fighting in the World War, there was no wartime censorship, and news of the outbreak became widely known, leading to the flu being called the Spanish Flu in many countries. In Spain, however, it was called French Flu or the Naples Soldier. In India, about 12 million people died of flu. In some US cities, people died so quickly that morticians couldn't cope with the bodies. According to Jessie Lee Brown Foveaux, who worked in the Fort Riley laundry during the epidemic: "They were piling them up in a warehouse until they could get coffins for them."

The disease started with cough, then headache. Temperature, breathing and heart rate increased rapidly. In the worst cases, pneumonia came next, the lungs filling with liquid, drowning the patients and turning them blue from lack of air. Patients bled from every orifice: mouths, noses, ears, eyes. Those who survived often suffered temporary or permanent brain damage. Several million developed encephalitis lethargica, in which victims were trapped in a permanent sleeplike and rigid state, as portrayed in the 1990 movie "Awakenings." In others, normal thought processes were impaired. During negotiations to end World War I, US President Woodrow Wilson was struck with flu, and people around him noted that his mental abilities never fully recovered. The French leader George Clemenceau had wanted harsher punishment of Germany than Wilson had desired. Clemenceau may have convinced Wilson in his weakened state to accept such harsh terms, which may have been one of the factors causing World War II.

Since flu is highly contagious early in the illness, even before symptoms appear, strict quarantine may be necessary to stop its spread during an epidemic. Australia kept its 1918 flu death rate relatively low by enforcing quarantines. However, in many parts of the world, public health officials hesitated to impose such measures, giving the disease time to gain a foothold. In the US city of Philadelphia, a rally of half a million people was planned in September 1918 to sell bonds to fund the war, at just the time when the flu started to infect residents. Although doctors warned the public health director to cancel the rally, he wanted to meet the city's quota to raise money for the war and refused to cancel the event. Within days after the rally, half a million city residents caught the flu.

Why was the 1918 flu so deadly? The influenza virus wasn't preserved at the time of the outbreak, at least on purpose. But in the late 1990's researchers Ann Reid, Jeffery K. Taubenberger, and their colleagues extracted and sequenced the genetic material of the virus, RNA, from tissue of victims who died in the pandemic. They used bits of lung that were preserved in formalin from victims on army bases or from victims buried in permafrost in the Alaskan village of Brevig Mission, where flu killed 85% of adults. Comparisons with known flu viruses in humans, pigs, and birds suggest that some genes of the 1918 virus came from birds or an unknown animal source. Other scientists then were able to show that the amino acid sequence of hemagglutinin protein from the 1918 virus had several changes from other flu viruses that may have helped it to easily bind and invade human cells, and that made the virus look different enough from earlier flu virus strains that people had no immunity.

The possibility exists that another flu pandemic will sweep the world like the one in 1918. This year, an H5N1 influenza virus has killed millions of birds and at least 30 people in southeast Asia. So far this virus strain has not evolved the ability to pass directly from human to human, but that possibility becomes more likely as the bird pandemic continues and humans remain in contact with chickens, ducks, and other birds. The virus has killed two-thirds of people reported to be infected. Dr. Tim Uyeki, an epidemiologist for the US Centers for Disease Control, says, ''you have the ingredients in Asia right now for a public health disaster."

But since sequences of this bird flu virus are known, it may be possible to develop a vaccine or set of vaccines to protect against it. At a special meeting of influenza experts on November 11th and 12th, World Health Organization influenza program chief Klaus Stohr said, "It is not only possible, but also important, that influenza pandemic vaccines be made available... and there's a shared responsibility needed to make that happen…. We have a huge window of opportunity now."

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The Pop Pop: How The Population Bubble Burst (part 2)

By Larry Baum

Part 1 of this story was published in the previous issue.

In past decades, a human population explosion was predicted for the 21st century as falling death rates were not being followed by falling birth rates in developing regions. However, it is now evident that birth rates are declining in poorer countries, closing the gap with death rates and thus slowing the growth of the world's population. In 1968, the United Nations Population Division predicted that the total human population would exceed 12 billion by 2050 (there are 6.3 billion people now), but the current expectation is for a plateau at nine billion.

Median fertility fell nearly in half from 5.4 births/woman in 1970 to 2.9 in 2000. African fertility fell but is still the highest, around 5, while Europe declined to well under the population replacement level of slightly over 2. The rest of the world is between 2 and 3.

Several factors may be responsible for the decline in fertility. Many people have moved from farms, where children help with chores, to cities, where children are not as helpful.

Health has improved through such developments as childhood vaccinations, greater food productivity, oral rehydration therapy for childhood diarrhea, cleaner water, hand-washing for midwives, vitamins for women and children, and antibiotic treatment. Life expectancy has doubled in the last century, from 30 to 60 years, and the childhood death rate has plunged. Since children are more likely to survive, parents feel less need to conceive as many.

Both average ages of marriage and rates of divorce have risen in both men and women. This has reduced the window of time for having children. Increased education of girls may be another factor in reduced fertility since there is a negative correlation between years of education and fertility for females.

Governments have increased support for contraceptive use. According to the UN's World Fertility Report 2003, the median use of modern contraception has increased in developing countries from 18% in the 1970's to 30% in the 1990's. China's one-child policy has reduced fertility by 4 children/woman, and large reductions in fertility have also occurred in many other countries, including Algeria, Iran, Mexico, Thailand, and Turkey.

Half the world's population growth is now in just six developing nations, Pakistan, India, Bangladesh, China, Indonesia, and Nigeria, in part because of their already large sizes.

In contrast, the populations of some developed countries are shrinking. In Italy and Japan, women have an average of only 1.3 children, and the level in eastern Germany is even lower. As a result, workers there face higher taxes and delayed retirement to support growing numbers of pensioners. To help solve the problem, governments are encouraging couples to have more children. Italy pays 1000 euros to couples having a second child, and for a third child Singapore pays a whopping S$18,000, about US$11,000. Somewhat ironically, the affected governments are continuing to limit immigration.

If current trends continue, regional fertility rates will gradually converge, and population growth will slow toward zero. However, the experience of the last few decades shows that forecasts can be wrong. Nevertheless, the impacts of changes in population growth are so great that humans will keep trying to predict our own numbers.

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