Dengue—A Fever From a Bite

By Awake! correspondent in the Philippines

UNNOTICED, a mosquito lands on the little girl’s bare arm. The insect quickly pierces her skin and taps the bloodstream. After a few moments, the mother glances at her daughter and spots the mosquito. With a quick swat, it is gone. Is that the end of it? Maybe not. The mosquito may be gone, but its brief invasion into the child’s bloodstream has left unwanted organisms that are capable of causing disease.

Within two weeks the child experiences chills, headache, pain behind the eyes, extreme aching in her joints, and a high fever. As the illness progresses, she develops a red rash and becomes completely exhausted. She has contracted dengue, a fever from a mosquito’s bite.

However, especially if the child has had a previous dengue infection, she may develop the more serious form of the disease, dengue hemorrhagic fever (DHF). With it, the capillaries leak, resulting in skin hemorrhages. There may be internal bleeding. Without proper treatment, the patient may experience profound shock and circulatory failure, leading to rapid death.

What exactly is dengue? Can it affect you? How can you protect yourself and your family? Let’s take a closer look.

What Is Dengue?

Dengue, also called breakbone fever, is just one of a number of diseases that can result from a mosquito’s bite. The actual cause of the disease is a virus. An infected mosquito (that is, a mosquito that has previously bitten an infected human) carries the virus in its salivary glands. In the process of biting a person to get blood, it transfers the virus to the human.

There are four types of dengue virus. Infection with one type does not provide immunity to the other three types. After one infection, if a victim is bitten by a mosquito carrying another type, the result can be DHF.

“Two Fifths of the World’s Population” at Risk

According to the World Health Organization (WHO), dengue threatens 2.5 billion people, “two fifths of the world’s population.” Asiaweek reported: “Over 100 tropical and sub-tropical countries have reported dengue outbreaks, and there are tens of millions of reported cases each year, with 95% of the infected being children.”

It is unclear when dengue was first recognized on the world scene. A report on “knee fever” in Cairo in 1779 may actually be referring to dengue. Since that time, dengue has been reported worldwide. Particularly since World War II, dengue has had a significant impact on human health, beginning in Southeast Asia. Multiple types of the virus began to circulate, and this led to the more dangerous hemorrhagic variety. A publication produced by WHO says: “The first real outbreak of haemorrhagic fever in Asia was recognized in Manila in 1954.” Other countries followed, notably Thailand, Vietnam, Malaysia, and neighboring areas. These early outbreaks in Southeast Asia had fatality rates ranging from 10 to 50 percent, but as more was learned about the disease, these rates dropped.

Since the 1960’s, laxity in programs to control the mosquito that carries the virus has contributed to an explosive increase in dengue. As dengue has spread, so has DHF. Only 9 countries had epidemics before 1970, but by 1995 this number had grown to 41. WHO estimates that yearly, 500,000 cases of DHF require hospitalization.

Although the disease is less known outside tropical areas, in some cases travelers to regions where there is a risk of contracting it have become infected and brought the disease home with them. For example, toward the end of 1996, The New York Times told of dengue cases in the United States—in Massachusetts, New York, Oregon, and Texas.

Particular Dangers of DHF

As noted earlier, DHF is the life-threatening form of dengue. One of the dangers of DHF is that people are fooled into thinking that it is not that serious. Many mistake it for a case of the flu. However, postponing action may allow the illness to advance to the more serious stage in which the blood platelet count drops drastically, hemorrhaging begins (internally or through the gums, nose, or skin), and blood pressure sinks. The patient may collapse. By the time the family realizes that the condition is serious, he is already going into shock. They rush him to the hospital. There, the doctors find that he is already experiencing circulatory failure. Because of the critical situation, intravenous fluid replacement is ordered.

Protecting Your Family

What can be done to minimize the effects of this disease? If the family lives where dengue is prevalent and a family member has a high fever lasting longer than a day, the family should wisely consult a doctor. This is particularly important if the sick one has other dengue symptoms, such as a rash or pain in muscles and joints or behind the eyes.

The doctor may take a blood test. Nonhemorrhagic dengue may require only simple treatment. But if testing indicates that it is DHF, the doctor will likely recommend careful fluid management. This may include oral rehydration solutions, such as those used for diarrhea, or, in more critical situations, intravenous fluid replacement using Ringer’s solution, saline solutions, or others. In treating cases of shock, the doctor may prescribe certain medications to help raise blood pressure and restore platelet levels.

If there is significant bleeding, doctors may be inclined to recommend a blood transfusion. Some may quickly recommend this without considering the alternatives. However, in addition to being against God’s law, this is usually unnecessary. (Acts 15:29) Experience has shown that careful management of circulatory fluids from the onset of the disease is the most important factor in the treatment. Cooperation between patient and doctor in this can help to eliminate confrontations over the matter of blood transfusion. This all emphasizes the importance of quick action when a person suspects DHF.—See the box “What Are the Symptoms?”

Preventive Measures

One of the main carriers of the dengue virus is the Aedes aegypti mosquito. This species is common to tropical and subtropical areas around the world. (See accompanying map.) Aedes aegypti mosquitoes thrive in highly populated areas. Controlling the mosquito is one of the keys to controlling the disease.

Mosquito control on a worldwide scale is not easy. However, there are things that you can do to help reduce the risk around your home. The female mosquito lays eggs in water. The larvae can develop in any container that will retain water for a week or so, such as abandoned tires, discarded cans, bottles, or open coconut shells. Getting rid of such containers will eliminate mosquito breeding sites. In addition, it is recommended that you turn buckets or boats upside down. Removing standing water from gutters will also help. Interestingly, at the beginning of the 1997/98 school year, the department of health in the Philippines discouraged the use of flowerpots in school classrooms for this reason.

If someone in the home contracts dengue, take steps to avoid his being bitten by other mosquitoes that may, in turn, carry the infection to others. A properly screened or an air-conditioned building can be a protection.

What about vaccination? An appropriate vaccine is not presently available. Research is being done to develop one, but this is complicated by the fact that complete protection would require immunization against all four types of dengue. Vaccination for only one could actually increase the risk of DHF. Researchers are hopeful that an effective vaccine may be available in five to ten years.

Some researchers have been trying another approach. By using genetic engineering, they hope to prevent the dengue virus from replicating in mosquito saliva. If this works as planned, such genetically engineered mosquitoes would pass on to their offspring a resistance to dengue. Although some progress has been made, it remains to be seen how successful this will be.

At present, eradicating dengue completely does not appear to be possible. But taking practical precautions can help you and your loved ones avoid life-threatening complications from dengue—a fever from a bite.

[Box on page 22]

What Are the Symptoms?

Symptoms of both dengue fever and dengue hemorrhagic fever (DHF)

• Sudden high fever

• Severe headachea

• Pain behind the eyes

• Joint and muscle pain

• Swelling of lymph nodes

• Rash

• Exhaustion

Symptoms more specific for DHF

• Sudden collapse

• Skin hemorrhaging

• Generalized bleeding

• Cold, clammy skin

• Restlessness

• Shock with weak pulse (dengue shock syndrome)

Do not delay in seeing a doctor if symptoms are observed. Children are especially at risk

[Footnote]

[Box on page 23]

Tips for Travelers

Occasionally, travelers to tropical zones are infected with dengue, but dengue hemorrhagic fever is much rarer because this more serious form is normally contracted after a second dengue infection. Here are some safety suggestions for travelers:

• Wear long-sleeved shirts and long pants

• Use a mosquito repellent

• Stay away from heavily populated areas

• Stay in accommodations where you can close the windows and keep the mosquitoes out

• If you develop a fever after returning home, tell the doctor where you traveled

[Map/Picture on page 23]

Areas with recent dengue activity

Areas at risk for a dengue epidemic

Range of “Aedes aegypti,” a dengue-carrying mosquito

[Credit Line]

Source: Centers for Disease Control and Prevention, 1997

© Dr. Leonard E. Munstermann/Fran Heyl Associates, NYC

[Pictures on page 24]

Possible breeding sites are (1) abandoned tires, (2) rain gutters, (3) flowerpots, (4) buckets or other containers, (5) discarded cans, (6) barrels

[Picture Credit Line on page 21]

© Dr. Leonard E. Munstermann/Fran Heyl Associates, NYC