The American Plague: The Untold Story of Yellow Fever, the Epidemic that Shaped Our History - Molly Caldwell Crosby (2006)

Part IV. United States, Present Day

In recent years, popular attention has been drawn to . . .
Ebola as the most frightening emerging infection of humankind.
However, patients with yellow fever suffer as terrifying
and untreatable a clinical disease, and yellow fever is
responsible for 1000-fold more illness and death than Ebola.

—Lancet Infectious Disease, 2001

Chapter 24. Epidemic

It was March 10, 2002, when Tom McCullough checked into the emergency room in Corpus Christi, Texas. He had been suffering for four days from cramping, abdominal pain and severe headache. Then, he developed a fever approaching 103 degrees. The doctors in the ER thought it could be rickettsial disease, a term that covers a number of infections caused by vectors like ticks, fleas or contact with animals. Most rickettsia can be controlled with antibiotics, so the doctors prescribed just that and released him from the hospital. Two days later, he was back again, this time with intractable vomiting. McCullough had been a healthy, forty-seven-year-old man, but he now appeared weak and febrile. He repeatedly asked his wife, “What is happening to me?”

A series of tests were performed, and he was treated for malaria though his blood test proved negative. McCullough developed anemia, his blood would not clot, and his kidneys and liver failed. He went into shock and developed seizures. He bled uncontrollably from the sites of his needle punctures. Tom McCullough died on March 15—leaving a wife and six children still wondering why.

McCullough’s illness and death were reported to the Centers for Disease Control and Prevention (CDC) in Atlanta, which began their own series of tests looking for dengue, St. Louis encephalitis, spotted fever, leptospirosis, Machupo virus and yellow fever—all viruses known to exist in South America. McCullough, it had been reported to the CDC, had just returned from a week-long fishing trip for peacock bass on Brazil’s Rio Negro. The brochure for the trip read, We do not suggest any inoculations of any kind for this trip . . . But to make sure you are worry free, consult with your personal physician.

It would seem that some vicious new virus had taken hold of Tom McCullough; instead it was an ancient one. One hundred years ago, doctors would have known immediately what killed him, but modern medicine takes longer. Today, there is a wealth of illnesses known to be caused by insect vectors of all types. There are antibiotics and vaccines to fight disease, and still, this fever seemed to defy contemporary medicine. At last, the autopsy showed antibodies to the yellow fever virus—McCullough’s internal struggle against a virus rapidly taking hold of his body. The CDC had reason to be concerned; McCullough was the third death from yellow fever since 1996, all three originating from trips to the Amazon region. Prior to that, there had not been a yellow fever death on American soil in nearly eighty years.

Tom McCullough had told his wife that he could not remember being bitten by a mosquito during the trip. He slept in an air-conditioned boat and had worn DEET. Still, a mosquito had apparently found him, following the scent of carbon dioxide in the tropical air, perhaps hovering unnoticed around his ankles or legs, biting several times as he moved. But it only took one bite, a pinprick he never even noticed, and the lethal virus made its way into his bloodstream. McCullough’s body had never come in contact with this virus before. He had not had a yellow fever vaccine, and his blood came from stock that had not seen this virus in over a century.

Had an Aedes aegypti mosquito in Texas bitten McCullough in the days before he checked into the hospital, hundreds more could have been infected. The virus would have been unleashed on a virgin population. In the mild Corpus Christi winter, virulent eggs could survive to the next summer when even more Aedes aegypti mosquitoes would carry the virus through another muggy Texas summer.

At first, the virus would move quietly into the population. People would begin showing up at local emergency rooms with high fevers and flu-like symptoms. They would be released when they showed signs of improvement—yellow fever’s convalescent period. But as many as 50 percent of those people, and possibly many more than that, would enter the toxic phase of the disease and die.Their deaths might be blamed on any number of diseases—pneumonia, hepatitis, influenza, West Nile. Though mosquito bites, swollen and pink, might appear on the skin, no one would think to investigate further. After all, these patients live in the United States. They had not traveled to a tropical country; they had just spent a summer evening outdoors, or found a striped mosquito trapped in their car, or missed a few places of skin when they sprayed Off! on their children playing in the backyard.

As the death toll began to mount, doctors in the local hospitals would begin reporting them to the state health department. Perhaps malaria or dengue had made its way from Central Americanorth. Health officials would be concerned. Resistant strains of malaria have been reported in recent years, and the CDC estimates that as many as 3,800 cases of dengue have appeared in the United States since the 1970s. Dengue is spread by the same mosquito that carries yellow fever. At last, the dead arriving from their homes or on gurneys in emergency rooms would begin to yellow, their skin taking on a bronze color, their eyes like sunflowers.

The state health department would contact the CDC, which, under international law, must contact the World Health Organization within twenty-four hours to report any disease with jaundice and bleeding. Since its inception in the 1950s, the WHO’s International Health Regulations have required reporting of only three diseases: plague, cholera and yellow fever. All three diseases are subject to international quarantine.

But in America, these diseases are so rare that doctors would doubtfully even recognize the symptoms in twenty-four hours. Americans traveling to the coastal areas of Texas for vacation would pick up the virus and fly home to cities like Houston, Dallas, Memphis and New Orleans, where entire colonies of Aedes aegypti live.

In 2005, the CDC published a detailed response to an epidemic of yellow fever in Africa and the Americas. Field investigators, border officials and vector control would arrive. They would contact the Global Alliance for Vaccines and Immunization to report an epidemic and request that mass vaccines be delivered within the week. Those who already have the virus would have little chance for survival—they would be part of the nonimmune population, the kindling that the virus relies upon to spread. Vaccines would be given to hospital personnel and military first, but postexposure, it would do little good. In the time it would take the vaccine to prompt the production of antibodies, the virus would have run its course, leaving its host either immune or dead.

A live vaccine, yellow fever can also have adverse effects. Infants, patients with depressed immune systems or anyone over the age of seventy-five cannot receive the vaccine. Though pregnant women are usually denied the attenuated vaccine for the safety of the fetus, the CDC would make an exception in the case of an epidemic. In the hospitals where yellow fever patients arrive, rooms would have to be screened and strictly quarantined. Lab technicians handling blood samples would have to follow strict procedure with gloves, masks and air purifiers.

A general panic would settle into the city and surrounding ones as educational warnings on television and radio recommended that people cover their beds in netting. Informational pamphlets would instruct people to empty any outdoor water containers around their homes. In spite of the summer heat, people would wear pants, long sleeves and socks with shoes. Store shelves would be cleared of Off! and any other DEET products. Windows would be screened. Water and food stockpiling might occur as people prepared to board themselves up in their homes, keeping their children indoors. Public pools and parks might close. Chemicals would be pungent in the air as people sprayed insecticides on their lawns and in their homes. Vector control units would send out patrols of trucks and crop dusters to mass spray.

The panic would worsen.

Vaccines from the Global Alliance for Vaccines and Immunization would arrive, but not enough in the event of a full-scale outbreak. The GAVI only recently began stockpiling the yellow fever vaccine. Six million doses are reserved each year for an epidemic, and they could take a few million more from their reserves for routine vaccine usage. The CDC would assess which portions of the population are most in need of the vaccine, reserving several for the personnel, military and hospital staff. Even if all six million vaccines arrived in a town like Corpus Christi, there would not be enough to inoculate cities the size of Houston and Dallas, much less other southern cities where the mosquitoes or infected people may have made their way.

Cases would continue to appear well into December, spiking every time another warm front moves through the country. At long last the epidemic would subside, though it would live on in the news and on the covers of magazines for months. Major vaccine production programs would begin, grown in chicken eggs over the next six months. And, hopefully, there would be enough vaccines ready for the approach of warm weather the following spring when yellow fever season arrived once again. That is not always the case—especially in underdeveloped countries. After an outbreak of yellow fever that killed thousands in Nigeria during the 1990s, it took ten years to clear the population of the virus. In order to prevent an epidemic, at least 80 percent of a country must have immunity to yellow fever.

According to the World Health Organization, even a single case of yellow fever must be treated as epidemic.