原文链接  https://www.mayoclinic.org/diseases-conditions/viral-gastroenteritis/symptoms-causes/syc-20378847?p=1

中文内容在英文下方

Viral gastroenteritis (stomach flu)

Overview

Viral gastroenteritis is an intestinal infection marked by watery diarrhea, abdominal cramps, nausea or vomiting, and sometimes fever.

The most common way to develop viral gastroenteritis — often called stomach flu —is through contact with an infected person or by ingesting contaminated food or water. If you're otherwise healthy, you'll likely recover without complications. But for infants, older adults and people with compromised immune systems, viral gastroenteritis can be deadly.

There's no effective treatment for viral gastroenteritis, so prevention is key. In addition to avoiding food and water that may be contaminated, thorough and frequent hand-washings are your best defense.

Symptoms

Although it's commonly called stomach flu, gastroenteritis isn't the same as influenza. Real flu (influenza) affects only your respiratory system — your nose, throat and lungs. Gastroenteritis, on the other hand, attacks your intestines, causing signs and symptoms, such as:

• Watery, usually nonbloody diarrhea — bloody diarrhea usually means you have a different, more severe infection

• Abdominal cramps and pain

• Nausea, vomiting or both

• Occasional muscle aches or headache

• Low-grade fever

Depending on the cause, viral gastroenteritis symptoms may appear within one to three days after you're infected and can range from mild to severe. Symptoms usually last just a day or two, but occasionally they may persist as long as 10 days.

Because the symptoms are similar, it's easy to confuse viral diarrhea with diarrhea caused by bacteria, such as Clostridium difficile, salmonella and E. coli, or parasites, such as giardia.

When to see a doctor

If you're an adult, call your doctor if:

• You're not able to keep liquids down for 24 hours

• You've been vomiting for more than two days

• You're vomiting blood

• You're dehydrated — signs of dehydration include excessive thirst, dry mouth, deep yellow urine or little or no urine, and severe weakness, dizziness or lightheadedness

• You notice blood in your bowel movements

• You have a fever above 104 F (40 C)

For infants and children

See your doctor right away if your child:

• Has a fever of 102 F (38.9 C) or higher

• Seems lethargic or very irritable

• Is in a lot of discomfort or pain

• Has bloody diarrhea

• Seems dehydrated — watch for signs of dehydration in sick infants and children by comparing how much they drink and urinate with how much is normal for them

If you have an infant, remember that while spitting up may be an everyday occurrence for your baby, vomiting is not. Babies vomit for a variety of reasons, many of which may require medical attention.

Call your baby's doctor right away if your baby:

• Has vomiting that lasts more than several hours

• Hasn't had a wet diaper in six hours

• Has bloody stools or severe diarrhea

• Has a sunken soft spot (fontanel)on the top of his or her head

• Has a dry mouth or cries without tears

• Is unusually sleepy, drowsy or unresponsive

Causes

You're most likely to contract viral gastroenteritis when you eat or drink contaminated food or water, or if you share utensils, towels or food with someone who's infected.

A number of viruses can cause gastroenteritis, including:

• Noroviruses. Both children and adults are affected by noroviruses, the most common cause of foodborne illness worldwide. Norovirus infection can sweep through families and communities. It's especially likely to spread among people in confined spaces. In most cases, you pick up the virus from contaminated food or water, although person-to-person transmission also is possible.

• Rotavirus. Worldwide, this is the most common cause of viral gastroenteritis in children, who are usually infected when they put their fingers or other objects contaminated with the virus into their mouths. The infection is most severe in infants and young children. Adults infected with rotavirus may not have symptoms, but can still spread the illness — of particular concern in institutional settings because infected adults unknowingly can pass the virus to others. A vaccine against viral gastroenteritis is available in some countries, including the United States, and appears to be effective in preventing the infection.

Some shellfish, especially raw or undercooked oysters, also can make you sick. Although contaminated drinking water is a cause of viral diarrhea, in many cases the virus is passed through the fecal-oral route — that is, someone with a virus handles food you eat without washing his or her hands after using the toilet.

Risk factors

Gastroenteritis occurs all over the world, affecting people of every age, race and background.

People who may be more susceptible to gastroenteritis include:

• Young children. Children in child care centers or elementary schools may be especially vulnerable because it takes time for a child's immune system to mature.

• Older adults. Adult immune systems tend to become less efficient later in life. Older adults in nursing homes, in particular, are vulnerable because their immune systems weaken and they live in close contact with others who may pass along germs.

• Schoolchildren, churchgoers or dormitory residents. Anywhere that groups of people come together in close quarters can be an environment for an intestinal infection to get passed.

• Anyone with a weakened immune system. If your resistance to infection is low — for instance, if your immune system is compromised by HIV/AIDS, chemotherapy or another medical condition — you may be especially at risk.

Each gastrointestinal virus has a season when it's most active. If you live in the Northern Hemisphere, for instance, you're more likely to have rotavirus or norovirus infections between October and April.

Complications

The main complication of viral gastroenteritis is dehydration — a severe loss of water and essential salts and minerals. If you're healthy and drink enough to replace fluids you lose from vomiting and diarrhea, dehydration shouldn't be a problem.

Infants, older adults and people with suppressed immune systems may become severely dehydrated when they lose more fluids than they can replace. Hospitalization might be needed so that lost fluids can be replaced intravenously. Dehydration can be fatal, but rarely.

Prevention

The best way to prevent the spread of intestinal infections is to follow these precautions:

• Get your child vaccinated. A vaccine against gastroenteritis caused by the rotavirus is available in some countries, including the United States. Given to children in the first year of life, the vaccine appears to be effective in preventing severe symptoms of this illness.

• Wash your hands thoroughly. And make sure your children do, too. If your children are older, teach them to wash their hands, especially after using the toilet. It's best to use warm water and soap and to rub hands vigorously for at least 20 seconds, remembering to wash around cuticles, beneath fingernails and in the creases of the hands. Then rinse thoroughly. Carry sanitizing wipes and hand sanitizer for times when soap and water aren't available.

• Use separate personal items around your home. Avoid sharing eating utensils, drinking glasses and plates. Use separate towels in the bathroom.

• Keep your distance. Avoid close contact with anyone who has the virus, if possible.

• Disinfect hard surfaces. If someone in your home has viral gastroenteritis, disinfect hard surfaces, such as counters, faucets and doorknobs, with a mixture of 2 cups (0.47 liters) of bleach to 1 gallon (3.8 liters) of water.

• Check out your child care center. Make sure the center has separate rooms for changing diapers and preparing or serving food. The room with the diaper-changing table should have a sink as well as a sanitary way to dispose of diapers.

Take precautions when traveling

When you're traveling in other countries, you can become sick from contaminated food or water. You may be able to reduce your risk by following these tips:

• Drink only well-sealed bottled or carbonated water.

• Avoid ice cubes, because they may be made from contaminated water.

• Use bottled water to brush your teeth.

• Avoid raw food — including peeled fruits, raw vegetables and salads — that has been touched by human hands.

• Avoid undercooked meat and fish.

By Mayo Clinic Staff

中文翻译（由软件翻译，可能有错误）：

病毒性肠胃炎（肠胃流感）

概述

病毒性胃肠炎是一种肠道感染，表现为水样腹泻、腹部绞痛、恶心或呕吐，有时还会发烧。

发展病毒性胃肠炎（通常称为胃流感）的最常见方式是通过与感染者接触或摄入受污染的食物或水。如果您身体健康，您很可能会康复而不会出现并发症。但对于婴儿、老年人和免疫系统受损的人来说，病毒性胃肠炎可能是致命的。

病毒性胃肠炎没有有效的治疗方法，因此预防是关键。除了避免可能被污染的食物和水之外，彻底和经常洗手是最好的防御措施。

症状

虽然它通常被称为胃流感，但肠胃炎与流感不同。真正的流感（流感）只会影响您的呼吸系统——您的鼻子、喉咙和肺部。另一方面，肠胃炎会攻击您的肠道，导致体征和症状，例如：

• 水样腹泻，通常是非血性腹泻——血性腹泻通常意味着您患有不同的、更严重的感染

• 腹部绞痛和疼痛

• 恶心、呕吐或两者都有

• 偶尔肌肉酸痛或头痛

• 低烧

根据病因，病毒性胃肠炎症状可能会在您感染后的一到三天内出现，并且可能从轻微到严重不等。症状通常只持续一两天，但有时它们可​​能会持续长达 10 天。

由于症状相似，很容易将病毒性腹泻与由艰难梭菌、沙门氏菌和大肠杆菌等细菌或贾第鞭毛虫等寄生虫引起的腹泻混淆。

什么时候去看医生

如果您是成年人，请在以下情况下致电您的医生：

• 你不能保持液体 24 小时

• 你已经呕吐超过两天了

• 你吐血了

• 你脱水了——脱水的迹象包括过度口渴、口干、尿液呈深黄色或很少或没有尿液，以及严重的虚弱、头晕或头晕

• 你注意到你的大便中有血

• 您发烧超过 104 华氏度（40 摄氏度）

对于婴儿和儿童

如果您的孩子出现以下情况，请立即就医：

• 发烧 102 华氏度（38.9 摄氏度）或更高

• 看起来昏昏欲睡或非常烦躁

• 有很多不适或疼痛

• 有血性腹泻

• 似乎脱水——通过比较他们喝水和小便的量与正常的量来观察生病的婴儿和儿童的脱水迹象

如果您有婴儿，请记住，虽然吐奶可能是您的宝宝每天都会发生的事情，但呕吐却不是。婴儿呕吐的原因有很多，其中许多可能需要就医。

如果您的宝宝出现以下情况，请立即致电您宝宝的医生：

• 呕吐持续数小时以上

• 六个小时没有尿过尿布

• 有血便或严重腹泻

• 在他或她的头顶有一个凹陷的软点（囟门）

• 口干或哭泣无泪

• 异常困倦、昏昏欲睡或反应迟钝

原因

当您吃或喝受污染的食物或水，或者与感染者共用餐具、毛巾或食物时，您最有可能感染病毒性胃肠炎。

许多病毒可引起肠胃炎，包括：

• 诺如病毒。儿童和成人都受到诺如病毒的影响，诺如病毒是全世界食源性疾病的最常见原因。诺如病毒感染可以席卷家庭和社区。它特别有可能在密闭空间的人群中传播。在大多数情况下，您会从受污染的食物或水中感染病毒，但也有可能在人与人之间传播。

• 轮状病毒。在世界范围内，这是儿童病毒性胃肠炎的最常见原因，他们通常在将被病毒污染的手指或其他物体放入口中时被感染。这种感染在婴儿和幼儿中最为严重。感染轮状病毒的成年人可能没有症状，但仍然可以传播疾病——在机构环境中尤其令人担忧，因为受感染的成年人可以在不知不觉中将病毒传染给他人。包括美国在内的一些国家/地区可以使用针对病毒性胃肠炎的疫苗，并且似乎可以有效预防感染。

一些贝类，尤其是生的或未煮熟的牡蛎，也会让你生病。虽然受污染的饮用水是病毒性腹泻的一个原因，但在许多情况下，病毒是通过粪口途径传播的——也就是说，携带病毒的人在上完厕所后没有洗手就处理了你吃的食物。

风险因素

肠胃炎在世界各地都有发生，影响各个年龄、种族和背景的人。

可能更容易患肠胃炎的人包括：

• 小孩子。儿童保育中心或小学的儿童可能特别脆弱，因为儿童的免疫系统需要时间才能成熟。

• 老年人。成人免疫系统在以后的生活中往往会变得效率低下。养老院中的老年人尤其容易受到伤害，因为他们的免疫系统减弱，并且与可能传播细菌的其他人密切接触。

• 学童、礼拜者或宿舍居民。人群聚集在一起的任何地方都可能成为肠道感染传播的环境。

• 任何免疫系统较弱的人。如果您对感染的抵抗力较低——例如，如果您的免疫系统受到 HIV/AIDS、化疗或其他医疗条件的影响——您可能尤其处于危险之中。

每种胃肠道病毒都有一个最活跃的季节。例如，如果您住在北半球，则在 10 月至 4 月之间更有可能感染轮状病毒或诺如病毒。

并发症

病毒性胃肠炎的主要并发症是脱水——水分和必需盐分和矿物质的严重流失。如果您身体健康并且喝的水足以补充因呕吐和腹泻而流失的水分，那么脱水应该不是问题。

婴儿、老年人和免疫系统受到抑制的人在失去更多的液体时可能会严重脱水。可能需要住院治疗，以便可以通过静脉补充丢失的液体。脱水可能是致命的，但很少见。

预防

预防肠道感染传播的最佳方法是遵循以下预防措施：

• 让您的孩子接种疫苗。包括美国在内的一些国家/地区提供针对轮状病毒引起的胃肠炎的疫苗。该疫苗在出生后第一年给予儿童，似乎可有效预防这种疾病的严重症状。

• 彻底洗手。并确保您的孩子也这样做。如果您的孩子年龄较大，请教他们洗手，尤其是在上完厕所后。最好使用温水和肥皂并用力搓手至少 20 秒，记得清洗角质层周围、指甲下和手的皱纹处。然后彻底冲洗。在没有肥皂和水的时候携带消毒湿巾和洗手液。

• 在家中使用单独的个人物品。避免共用餐具、水杯和盘子。在浴室使用单独的毛巾。

• 保持距离。如果可能，避免与任何感染病毒的人密切接触。

• 对硬表面进行消毒。如果您家中有人患有病毒性胃肠炎，请使用 2 杯（0.47 升）漂白剂和 1 加仑（3.8 升）水的混合物对硬表面（例如柜台、水龙头和门把手）进行消毒。

• 看看你的托儿中心。确保中心有单独的房间来换尿布和准备或供应食物。有换尿布台的房间应该有一个水槽和一个卫生的处理尿布的方法。

旅行时采取预防措施

当您在其他国家/地区旅行时，您可能会因受污染的食物或水而生病。您可以通过遵循以下提示来降低风险：

• 只喝密封良好的瓶装水或碳酸水。

• 避免使用冰块，因为它们可能是由受污染的水制成的。

• 使用瓶装水刷牙。

• 避免人手接触过的生食，包括去皮水果、生蔬菜和沙拉。

• 避免未煮熟的肉和鱼。

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