What Is Malaria? Symptoms, Causes, Diagnosis, Treatment, and Prevention

疟疾是一种威胁生命的疾病，由某些蚊子在温暖的气候下携带的寄生虫引起。

The parasites that cause malaria attack your red blood cells, typically causing a high fever, shaking chills, and other symptoms that may develop into life-threatening complications.

Most cases of malaria occur in sub-Saharan Africa and South Asia, but the disease also affects several other areas of the world, including Latin America, Southeast Asia, and Oceania.

• Fever
• Shaking chills
• 头痛
• Muscle aches
• 疲劳
• Profound weakness
• Nausea and vomiting
• 胸部或腹痛
• 咳嗽

• High body temperature
• 脾脏扩大
• Mild黄疸(elevated levels of bilirubin)
• Enlarged liver
• Increased respiratory rate

在疟疾罕见的国家，该疾病可能无法识别，因为其症状通常与其他感染的症状相似。

通常，疟疾从雌性的唾液中获得血液Anopheles昆虫后，蚊子以这种疾病为食。

Parasites That Cause Malaria

恶性疟原虫This species is found in tropical and subtropical regions worldwide, but it’s especially common in Africa.

恶意malaria is the deadliest form of malaria because it multiplies rapidly, rupturing red blood cells. These damaged cells can clog small blood vessels, including in your brain.

P. vivaxThis species is found mostly in Asia, Latin America, and some parts of Africa.

P. vivaxhas a dormant stage in the liver. As a result, it can invade your blood up to two years after the infecting蚊子叮咬, making you sick again.

These delayed infections (relapses) can also reintroduce malaria to areas of the world where it was previously eliminated.

P. ovale该物种主要在非洲和西太平洋岛屿上发现。像P. vivax，it can also remain dormant in your liver and cause relapses months or years later.

P. malariae该物种在全球范围内找到。如果未经治疗，它可能会引起慢性终身感染或严重的并发症，例如肾病综合征，一种严重的肾脏疾病。

P. Knowlesi这个物种被发现整个东南亚macaque monkeys. It can also infect humans and progress rapidly to severe infection.

Malaria Risk Factors

自1950年代初以来，美国一直在美国一直在进行疟疾的传播。通过水管理，杀虫剂以及其他治疗和预防工作的结合，有效地消除了该疾病。

But there are numerous cases each year of travelers leaving the United States, becoming infected, and returning to the country.

Occasionally, a small outbreak of malaria occurs in the United States, when local mosquitoes spread the disease from an infected traveler. So far, these episodes have been contained effectively, without malaria posing an ongoing threat.

Destination-related risk factors include:

Geographic regionAreas of the world where malaria is endemic (circulates widely) tend to be tropical, subtropical, or at low elevations.

这是因为寄生虫需要温暖的温度才能在蚊子内成熟。

The Centers for Disease Control and Prevention has atable of malaria information by countryto see if your travel destination has endemic malaria.

In general, your risk is higher if you travel to sub-Saharan Africa than most areas of Asia or the Americas.

住宿类型Lodging that has window screens or air conditioning poses a lower malaria risk than open-air or tented accommodations.

You’re also at greater risk if your itinerary includes outdoor dining or entertainment, especially in the evening.

SeasonHotter and wetter times of the year tend to be associated with greater malaria transmission.

这样做的原因之一是，降雨可以产生水的收集，鼓励传播疟疾的蚊子的繁殖。

It’s possible that during cooler times of the year, you won’t need to take as many preventive measures if you travel to certain areas where malaria is endemic.

Risk factors related to the type of traveler include:

怀孕If possible, travel to an area with malaria transmission should be delayed until after giving birth. If delaying the trip isn’t possible, it’s essential to take a drug to help prevent malaria.

Malaria during pregnancy raises the流产的风险, premature birth, and low birth weight, reducing the chances of the baby’s survival.

Visiting friends and relativesPeople who are originally from an endemic region but have moved, and then go back to visit, are the group at highest risk for malaria in the United States.

A lot of these people don’t know that they need to take medicine to prevent malaria. Some may believe they have immunity from growing up in a malaria-prone area, but any such immunity is only temporary and is quickly lost when someone moves away.

与游客或商务旅行者相比，拜访朋友和亲戚的人也可能在目的地国家度过更多的时间，并留在私人住宅而不是酒店。

It’s important to get an accurate diagnosis before startingtreatment for malaria和to get the diagnosis as early as possible. Your treatment may be guided by test results from the diagnostic process.

To diagnose malaria, your doctor will ask you about your health and travel history, perform a physical examination, and order血液检查.

• Whether you have malaria
• What kind of parasite is causing your malaria
• Whether your parasite is resistant to certain drugs

In the United States and other areas where malaria is uncommon, diagnosing malaria can be difficult mostly because doctors may fail to consider malaria as a possible diagnosis and not order the right tests at the start.

Prognosis for Malaria

• Infection with恶性疟原虫parasite (found in much of sub-Saharan Africa)
• Being an infant or young child
• Being an older adult
• Being pregnant
• Traveling from an area without malaria

More typically, this incubation period, defined as the time after infection occurs but before clinical symptoms develop, usually lasts from 7 to 30 days, depending on the type of parasite.

Taking a preventive drug before you travel to an area with malaria can also lengthen the incubation period and delay the appearance of symptoms by weeks or even months.

You may decide to choose or reject a specific medicine based on its possible side effects, dosing schedule, or safety during pregnancy.

If you develop malaria, your doctor will devise your treatment plan depending upon where you got infected, the parasite causing your malaria, and the severity of your symptoms, among other factors.

药物选择

In general, the same drugs are used to help prevent malaria if you’re traveling to an area where it’s spread, and to treat malaria if you develop the disease.

通常用于预防和治疗疟疾的药物包括：

Artemisinin-based combination therapies (ACTs)These combination medicines are each designed to fight malaria parasites in different ways.

ChloroquineThis drug is preferred whenever it’s likely to be effective, but many parasites are now resistant to it.

Other drugs that are less commonly used to help prevent or treat malaria include:

• Malarone (atovaquone and proguanil)
• Vibramycin (doxycycline) or Monodox (奎宁和doxycycline)
• 甲氟喹
• Primaquine

预防疟疾

There are medications that can help prevent illness if you become infected, but none of these drugs is 100 percent effective.

防止蚊子叮咬对预防疟疾至关重要。Anopheles黄昏和黎明之间咬人的蚊子，有时喜欢住在房子里。

• 避免黄昏和黎明之间的户外暴露
• Wear clothing that minimizes exposed skin
• Wear insect repellent on your skin that contains DEET
• Sleep under a bed net treated with an insecticide (such as permethrin)
• 穿氯菊酯或氯菊酯喷雾剂处理的衣服（可在户外供应商店购买）
• Stay in well-screened or air-conditioned rooms

• Young children
• 孕妇
• People without any previous exposure to malaria parasites

Breathing issuesMalaria can cause fluid to accumulate in your lungs, making breathing difficult.

Organ failureWhen you have malaria, your kidneys or liver can fail, or your spleen may rupture.

Brain problemsDamage to your red blood cells caused by malaria can block small blood vessels in your brain, leading to swelling and possible brain damage, also known as cerebral malaria. This condition can lead to coma or death.

AnemiaDamaged red blood cells can result in inadequate circulation of oxygen and vital nutrients in your blood.

低血糖Severe malaria can result in dangerously low blood glucose.Quinine, a drug used to treat malaria, can also lead to reduced blood sugar levels. If your blood sugar drops too low, coma or death can result.

Between 2010 and 2016, worldwide efforts successfully reduced the prevalence of malaria by 18 percent. The largest regional decline, 48 percent, occurred in South Asia and Southeast Asia.

But the WHO estimates that in 2016, there were still 216 million cases of malaria, leading to 445,000 deaths.

在令人不安的发展中，疟疾病例从2014年到2016年开始再次增加，拉丁美洲的增长最大。

Mosquitoes are more than just a nuisance — they can carry serious and potentially fatal diseases like theZika,基孔肯雅, and West Nile viruses, as well as malaria parasites.

同样重要的是要穿着长袖和裤子在您自己和蚊子之间保持距离，并尽可能留在空调或筛选区域。

Some mosquito-borne illnesses have no specific treatment, while others — like malaria — have effective treatments that should be started as soon as possible.

Learn More About Mosquito Bites That Spread Disease

Malaria can be a confusing and scary disease. The following organizations and websites offer information and support that may help you understand and deal with a new diagnosis, as well as how to take the necessary precautions to protect yourself.

Centers for Disease Control and Prevention — Malaria

This online portal can connect you to information on nearly every aspect of the disease, from facts and statistics to information for travelers. You can dive into details about how malaria is diagnosed and treated, or read about prevention efforts around the world.

World Health Organization — Global Malaria Programme

This online resource links to information on various aspects of the WHO’s efforts to fight malaria, from controlling mosquitoes to diagnostic testing and new treatment strategies to disrupt transmission of the disease.

National Institute of Allergy and Infectious Diseases — Malaria

美国国家卫生研究院的这种部门着重于疾病研究，包括开发vaccine for malaria和other diseases spread by mosquitoes.

MedlinePlus — Malaria

该网页链接到有关许多不同主题的信息，包括选择一种药物来帮助防止疟疾，发现假药和对该疾病的诊断测试。

Additional reporting byErin Archer Kelser, RN.