A Modern Menace: Emerging and Reemerging Diseases

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A Modern Menace

Emerging and Reemerging Diseases

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This past April, when the first cases of H1N1 swine flu were detected in Mexico and the United States, health officials around the world went on high alert.

Surveillance measures were put in place. Pharmaceutical companies stepped up production of antiviral drugs. In cities with confirmed cases, schools were closed. Large public gatherings, such as sporting events and concerts, were canceled. Malls, restaurants and other public places were empty. The scenes were very similar to what happened during the SARS and avian flu outbreaks that unfolded in Asia earlier this decade.

Aided by modern transportation, the virus spread rapidly. On June 11, with more than 125,000 confirmed cases and 140 deaths in 73 countries, the World Health Organization (WHO) finally declared the never-before-seen virus a pandemic—a global disease outbreak. The organization had long hesitated to take such a step—declaring the first global flu epidemic in 41 years—lest widespread panic result.

What the final outcome will be remains to be seen. With the arrival of summer in the northern hemisphere—and warm temperatures that flu bugs don't like—the spread slowed considerably. While there have been a large number of infections, this strain has been milder than originally feared and has been responsible for a relatively small number of fatalities.

Still, "that may only be the lull before the storm," warned Richard Besser, M.D., acting director of the Centers for Disease Control (CDC) in Atlanta, Georgia. His concern is over what will happen this fall when the traditional flu season begins. "What has been seen with previous outbreaks is flu goes away in the summer," he noted. "But during the winter flu spreads better, so the virus could go away and come back."

"I believe we are not out of the woods yet," added Christopher Ohl, M.D., associate professor of medicine in the section on infectious diseases at the Wake Forest University School of Medicine in Winston-Salem, North Carolina. "I am concerned this virus is going to be with us for a while. It could change, become more virulent, have an increased secondary transmission rate...in the future."

Of course, the spread of swine flu isn't the only disease problem health officials are concerned about right now. Let's consider the scope of the threat before us, look at some of the underlying causes, and see what light the Bible sheds on how the situation has developed and where things could go from here.

Deadly pathogens emerging or reemerging

Currently the WHO is monitoring about 40 emerging infectious diseases. These have been around only a few decades.

The list includes acquired immune deficiency syndrome (AIDS), Ebola, dengue hemorrhagic fever, Lassa fever, Nipah, Hendra, hantavirus, Marburg, monkeypox, mad cow disease (BSE), severe acute respiratory syndrome (SARS), West Nile virus, Lyme disease, Legionnaires' disease and the cyclospora parasite. These pathogens—disease-causing agents—have either mutated or genetically recombined to become new strains or novel microbes, or they may have existed for millennia but weren't discovered until recent years.

According to the WHO, at least one new infectious disease has emerged each year since 1980, many of which evade traditional therapies and have no vaccine or cure. "There are far more virulent, very difficult-to-treat infectious diseases today than there were 20 or 30 years ago," warns Klaus Stohr, D.V.M., Ph.D., director of the influenza task force for the WHO in Geneva, Switzerland.

At the same time, old infectious diseases once believed to be controlled, such as tuberculosis, staphylococcus, cholera, malaria, hepatitis, influenza and diphtheria, are reemerging as deadly new, often drug-resistant strains, or are springing up in new regions of the world.

With so many deadly pathogens coming on the scene, notes Dr. Stohr, "infectious diseases are once again the leading cause of death in the world—something that hasn't been the case since the pre-antibiotic era of the early 1900s." Of the estimated 57 million deaths that occur annually in the world, the WHO estimates that 15 million of them are directly caused by infectious diseases. Millions more deaths are due to secondary effects of infections.

Scientists have identified close to 200 bacterial, viral, parasitic and fungal pathogens that are linked with emerging and reemerging infections among human beings. There could be another 1,000 out there, according to Dr. Stohr. They just haven't been introduced yet into the population.

At least 75 percent of these pathogens are zoonoses—meaning they are transmitted between animals and people—which makes these diseases even more problematic. Transmission can occur through direct contact with an infected animal's blood, saliva, urine or feces, or via an intermediate vector—typically an insect or rodent—that gets the pathogen from an infected animal reservoir and then passes it to people.

"Zoonotic diseases cannot usually be eradicated due to the fact that it is not possible to eliminate all of the animal reservoirs or vectors that might be carrying the zoonosis," explains David Freedman, M.D., professor of medicine in the division of geographic medicine at the University of Alabama.

"Even if you developed a vaccine and a cure for a particular zoonotic disease and it was somehow possible to simultaneously treat every person in the world that had it," he observes, "there are still animals that can transmit that disease back to humans and continue the spread of that pathogen."

Deadly epidemics prophesied

If you are familiar with end-time Bible prophecy, none of this may be a surprise to you. Perhaps what immediately comes to mind is the four horsemen of the Apocalypse, and in particular the fourth.

The apostle John describes the horse and rider this way: "When He opened the fourth seal, I heard the voice of the fourth living creature saying, 'Come and see.' So I looked, and behold, a pale horse. And the name of him who sat on it was Death, and Hades [the grave] followed with him" (Revelation 6:7-8, emphasis added throughout).

The latter part of this verse refers to death resulting from "the beasts of the earth." Considering the huge number of deaths described here, this could well refer to epidemics caused by animals that transmit and carry infectious diseases.

In Jesus' parallel prophecy in Matthew 24, He reveals the true identity of this pale green horse: "And there will be...pestilences" (verse 7). The fourth horseman symbolizes climactic, globe-encircling plagues and pandemics. We need only consider the devastating "black death"—bubonic plague that killed tens of millions worldwide in three great waves—to understand how horrifyingly real this prophecy can be.

Many factors behind pandemics

That's the simple explanation for why these outbreaks will intensify. Yet there are a lot of factors behind these pandemics. Many believe mankind is actually creating its own disease problems, albeit unintentionally.

"In almost every case humans are the most important single factor in the surge of new diseases, whether it's feeding cow tissue to cattle to cause mad cow disease, people eating exotic animals in the case of Ebola, or air travel spreading dengue around the world," claims Thomas Monath, M.D., chief scientific officer with Acambis Inc., a vaccine development company based in Cambridge, Massachusetts.

We are not simply victims of emerging infections, he says, but we're making changes in our environment or lifestyles to cause the emergence or spread of disease. Most of the change that has occurred involves several key areas.

• Agricultural practices and consumption of exotic animals

One of the primary ways new diseases emerge is through what biologists call "genetic recombination." This can happen when two or more animal species come in contact with each other and exchange the viruses that each carries.

"Two different viruses may infect the same cell. Then the genomes get jumbled, and a totally novel virus emerges—which contains genetic material from both parental strains," explains Roy Anderson, fellow of the Royal Society (FRS) and professor of infectious disease epidemiology at Imperial College of the University of London.

One way this is happening more and more is through a farming method which is becoming an increasingly common practice in Asia.

"Ducks or chickens are kept in cages hung above pigs, which are housed in pens directly above fishponds, where other types of fowl may also swim and eliminate their own wastes," notes Bruno Chomel, Ph.D., D.V.M., a veterinary epidemiologist specializing in zoonotic diseases at the University of California College of Veterinary Medicine.

Farmers use this method to save money on pig feed and increase yields of fish. The pigs feed on the duck droppings, and the pig manure fertilizes the fishponds. "The problem is, it puts ducks and other waterfowl, which are major reservoirs of influenza viruses—although it doesn't affect them—in direct contact with pigs, which may also be harboring influenza viruses," Dr. Chomel says.

A pig that eats duck droppings can take in any viruses the ducks may have, which may include both avian and human flu viruses. Those can combine with the pig's influenza viruses, and then they'll all be mixed up inside the pig's stomach.

That is how the H1N1 influenza virus—which is a mixture of avian, human and pig flu viruses—came to be. One of the reasons scientists are so concerned about the current swine flu outbreak is that it could recombine with a more virulent strain before returning to the northern hemisphere in the fall flu season.

"If a human flu virus, which is easily transmissible to humans, combines with a virulent and novel duck or swine flu, that is when you have problems," Dr. Chomel says. "You get the worst of both, together in one virus."

Recombination can also occur when humans eat nondomesticated exotic animals. In China, exotic animals like civet cats, coral snakes, tree shrews, flying squirrels, badgers, martens and pangolins are considered delicacies. In Africa, monkeys, apes, aardvarks and rats are all popular meat choices. Guinea pigs, capybaras and armadillos are commonly eaten in Central and South America.

When people consume these meats, any viruses the animal may have been carrying can combine with viruses the person may have. The result may be a new pathogen that infects human beings.

That is apparently how HIV, the deadly virus that causes AIDS, emerged. HIV is a fusion of the simian immunodeficiency virus (SIV), which infects monkeys and apes, and a similar type of virus that infects people. "SIV was transferred to humans as a result of monkeys being killed and eaten or their blood getting into cuts or wounds on the hunter," Dr. Freedman says.

The bottom line, says Dr. Chomel, is "the practice of consuming wild species opens the door for a much wider variety of pathogens—those of wild animals—to come in contact with humans and develop transmissibility."

• Changing land use increases contact

Ecological changes often cause disease emergence. "There are environments in the developing world that used to be quite remote that are now much less so as a result of human activities like deforestation, dam projects, irrigation, road construction and extensive agriculture," says Jim Hughes, M.D., director of global infectious disease programs at Emory University and former director of the National Center for Infectious Diseases at the CDC.

These remote wilderness areas are home to some unique microbes—bacteria, parasites or viruses not found anywhere else. When people enter these ecosystems, they encounter these pathogens for the first time. For example, mankind's first contact with the Ebola virus occurred in the late 1970s when people began clearing the rainforests of the Democratic Republic of Congo.

The animal inhabitants themselves can also contribute to the spread of deadly microbes. "Once forests are cleared, the wildlife that used to live there have no choice but to migrate further out in search of food and land in which to live," says Stephen Corber, M.D., director of prevention and control for the Pan American Health Organization in Washington, D.C.

"A lot of times they end up in suburbs and farming communities where they make contact with people," he says. "If they're bringing diseases with them, that's when you have problems."

• Rapid international travel allows quick spread

Since the third quarter of the 20th century, individuals have been able to travel huge distances in a matter of hours—well within the incubation period of many infectious diseases. "Today anyone can get on a plane and get to the other side of the world in a matter of 24 to 36 hours," notes Dr. Hughes.

The speed of travel enables someone in North America, Europe or Asia to go on safari in Kenya, pick up the Ebola virus or some other pathogen, fly back home, pass unnoticed through immigration and customs checks, and then spend the next few days back at work before suddenly getting sick. During the incubation period—the time between getting infected and developing clinical signs of disease—this person may expose hundreds of people to the virus.

"People can be spreading disease and not even know they are ill," warns Hugh Pennington, M.D., Ph.D., president of the Society for General Microbiology in the United Kingdom and honorary professor of medicine at the Institute of Medical Sciences at the University of Aberdeen in Scotland.

This is in sharp contrast to past days when people traveled by ship. It may have taken several weeks to travel from one continent to another. "If someone had picked up a virus before getting on the ship, he would have developed that disease while still on board," Dr. Pennington says. "Upon arrival, it would have been obvious to port authorities which passengers were sick and needed to be quarantined."

As illustrated by the recent rapid spread of the H1N1 swine flu virus, modern travel can allow deadly pathogens to quickly outrace our best preventative measures.

• Poverty and disease inextricably linked

Not surprisingly, the poorest nations usually have the worst problems with infectious diseases. Sadly, poverty levels appear to be on the increase for much of the world. According to a 2008 United Nations report, more than 80 countries have lower per capita income today than at the beginning of the 1990s.

"As poverty levels climb, so does the incidence of disease," says Dr. Anderson. The poor are often malnourished, lack understanding of proper hygiene, have no access to medical care and live in densely populated slums—perfect conditions for the transmission of diseases.

One of the most desperate regions of the world is sub-Saharan Africa. A 2004 World Bank report found that close to half the population in this region lives in poverty, and this percentage is projected to increase in the years ahead.

But, warns Dr. Anderson, "This is not just a concern for Africa." Just as diseases do not stay in the poorer parts of a town, they do not confine themselves to poorer nations. "Many of the diseases that Western nations are contending with today got their start in the developing world," he adds.

Sooner or later, there's a visitor to a disease- infested area, or someone from that area travels to another region and then transports the pathogen to a new part of the world.

• Urbanization aids disease transmission

Increasing numbers of people, particularly in the developing world, are moving from rural areas to large cities to find work. In this way, contagions that may once have been obscure and localized in sparsely inhabited villages reach large population centers. Once in a city, the newly introduced infection multiplies among the local population and then spreads farther along highways and railroads and by airplane.

Many end up living in overcrowded "megacities"—huge urban conglomerations of 5 million or more residents. There are at least 41 megacities in the world today, most of which are in less-developed nations. In contrast, 50 years ago there were just eight megacities in the world, all but two of these in developed countries. Experts predict that by 2015, 59 megacities will exist, 48 in developing nations.

"Pathogens like dense populations because it promotes transmission from person to person," Dr. Anderson explains. Because the populations of megacities have grown so rapidly, most are not prepared to deal with such large numbers of residents, nor are their local economies usually strong enough to finance a lot of city improvements.

"Sewage and water systems are often inadequate, resulting in water supplies that are tainted with deadly bacteria," Dr. Anderson says. "There may not be enough hospitals, so when people do get sick, they cannot get the medical care they need." Additionally, he adds, most megacities are located in tropical or subtropical regions where infectious microbes thrive.

• Forced displacement due to war or civil strife

The United Nations estimates there to be a record high of 35.6 million refugees and internally displaced persons in the world today. These are people who've been forced to flee their homes due to internal conflict, war or persecution. The majority are from war-torn regions of sub-Saharan Africa, the Middle East, Southern Asia and Latin America. In recent years the number of displaced people has steadily risen due to the increasing number of conflicts in the world.

This trend has a direct impact on the proliferation of infectious diseases. "Refugees are often in poor health and very susceptible to infectious agents. Any pathogens they may be infected with are transported with them on their route and to wherever they end up," Dr. Monath explains.

Not only that, he continues, "the temporary settlements or camps they may be living in are typically overcrowded, have poor sanitation, are infested with rodents and other vectors, and the food and water supplies may be contaminated—just what bacteria need to flourish."

A case in point would be the 800,000 Rwandan refugees who migrated into Zaire in 1994. Cholera and shigella dysentery swept through the camps, killing nearly 50,000 people in the first month.

• Human morality and disease

The 1960s brought dramatic changes in human morality, particularly in terms of sexual behavior. "Whereas having multiple or concurrent sexual partners was unacceptable in the early 1900s, by the latter half of the 20th century it had become the norm in many societies," notes Dr. Pennington.

Not only had "casual sex" among heterosexuals become acceptable, men having sex with other men became more commonplace. At the same time, intravenous drug use became rampant, with drug users often sharing needles with other injectors.

It all fueled the spread of HIV, hepatitis C, genital herpes and other sexually transmitted diseases—all of which are transmitted through the transference of body fluids.

• Overuse of antibiotics creates deadly new superbugs

Widespread antibiotic use—often when antibiotics weren't called for—has created new antibiotic-resistant bacteria. "Patients will often insist they need an antibiotic when they have a cold or the flu, and sometimes doctors will give in to these demands," observes Trish Perl, M.D., director of hospital epidemiology and infection control at Johns Hopkins University in Baltimore, Maryland. The problem is that colds and flu are caused by viruses, which are not treatable with antibiotics.

According to the CDC, up to 40 percent of antibiotics prescribed in doctor's offices are for viral infections. This is not always due, however, to patients demanding they get an antibiotic. Sometimes physicians prescribe antibiotics when they can't make a definite diagnosis or "just in case" bacteria are present.

"With so many antibiotics in the environment, we're pressuring these bacteria to evolve into resistant strains," Dr. Perl asserts. "A particular drug may be prescribed so much that sooner or later the bacterium outsmarts it and learns how to grow within that environment." At that point, the particular drug is no longer effective at treating that type of bacteria.

Dr. Pennington explains the process this way: "Any population of organisms, bacteria included, naturally includes variants with unusual traits—in this case, the ability to withstand an antibiotic's attack on a microbe. When people take antibiotics, the drug kills the defenseless bacteria, leaving behind—or 'selecting'—those that can resist it. These renegade bacteria then multiply and become the predominant microorganism."

Adding to the problem, North American livestock producers have been unnecessarily feeding antibiotics to their animals to try to promote growth and as a preventative disease-control measure. This has turned the livestock into a reservoir of drug-resistant germs. When people eat undercooked, contaminated meat, they can become infected with antibiotic-resistant bacteria.

Today there are drug-resistant strains of tuberculosis, malaria, streptococci and salmonella—to name a few "superbugs" that have emerged in recent years. Because they have the antibiotic-resistant gene in them, they are considered to be genetically new organisms. "Some infections are now so resistant to the drugs we have available that they are virtually untreatable," Dr. Hughes says.

The infamous "flesh-eating bacteria," methicillin-resistant staphylococcus aureus (MRSA), is one of these terrifying new superbugs regularly making headlines.

Biblical perspectives

To students of the Bible, many of the factors just discussed are obvious violations of biblical instruction. A lot of the zoonotic diseases plaguing our modern societies would never have become a problem if people weren't consuming exotic or biblically "unclean" animals, which harbor a lot of contagious diseases that domesticated "clean" animals do not. We're told in Leviticus 11 and Deuteronomy 14 which types of animals should and should not be eaten.

Many of those living in overcrowded megacities and refugee camps are faced with inadequate waste disposal systems, resulting in contaminated food and water supplies. This is another area addressed in the Bible. Deuteronomy 23:9-14 says that human wastes were to be buried outside the community, away from where people were living.

The Bible is clear about what constitutes sexually immoral behavior, which is the root cause of the spread of AIDS and other sexually transmitted diseases plaguing our planet. In Leviticus 18 and 20, God prohibits incestuous relationships, extramarital and premarital sex, homosexuality and unnatural acts with animals. Homosexuality is specifically addressed again in Romans 1:27 and 1 Corinthians 6:9. The Bible tells us in 1 Corinthians 6:18 that "he who commits sexual immorality sins against his own body."

Ultimately though, disease outbreaks and pandemics are a result of mankind's broken relationship with God.

When God brought the Israelites out of Egypt, He told them: "If you diligently heed the voice of the Lord your God and do what is right in His sight, give ear to His commandments and keep all His statutes, I will put none of the diseases on you which I have brought on the Egyptians. For I am the Lord who heals you" (Exodus 15:26).

On the other hand, God warned of consequences for disobedience, including disease outbreaks (Leviticus 26:21, 25; Deuteronomy 28:15, 21-22, 27-28). Nevertheless, the Israelites persistently disobeyed Him. So has every society since, and mankind continues to reap the consequences.

The only real solution to the threat of devastating contagions is to turn to God in repentance—seeking and remaining committed to His ways. You as an individual can turn to God, and He will see you through the dark times ahead. This includes worsening pandemics, as the world at large is not yet ready to submit to God's will.

Today, humanity as a whole is cut off from God. His promise of protection from disease isn't there, but someday it will be. Jesus Christ will return to earth and establish God's everlasting Kingdom (Revelation 19:11-16). We can look forward to that day when mankind will be united with its Creator and will receive all the blessings of living God's way of life—which includes good health and a world free of disease outbreaks. GN