什么是流行性感冒？
日本脑炎 (JE) 是 a rare but potentially serious disease caused by infection with Japanese encephalitis virus (JEV). JEV is a flavivirus (other flaviviruses cause diseases including 黄热病, dengue and Murray Valley encephalitis). Spread to humans through mosquito bites, JEV is a leading cause of vaccine-preventable encephalitis (brain inflammation) in Asia and the Western Pacific.
要找什么？
Most people infected with JEV do not develop symptoms or develop mild symptoms only. However, approximately 1 in 250 people infected will experience severe clinical illness. If symptoms develop, they will 发生 5 to 15 days after exposure can include fever, diarrhoea and rigors (episodes of shivering and feeling cold). FeAtures of severe illness with encephalitis include Headache, confusion, vomiting, paralysis, seizures, neck stiffness, disorientation and coma. JE has A mortality rate of 20 to 30%, with permanent neurological disability occurring in 30 to 50% of survivors.
结核病是如何传播的？
JE is a zoonotic disease and can spread to humans when a mosquito bites an infected animal (mostly water birds or pigs) and then bites a human. It cannot be transmitted from person to person, or through eating pork or pig products. Horses can be infected with JEV; however, they cannot transmit the disease further.
When JE occurs during pregnancy, infection can be transmitted to the unborn baby.
In most temperate areas of Asia and Australia, JEV is transmitted mainly during the warmer months. In the tropics and subtropics, transmission can occur year-round but often intensifies during the rainy season when mosquito numbers are greater.
流行病学
There are an estimated 100,000 clinical cases of JE globally each year, resulting in approximately 25,000 deaths. JE is most common across Asia and the Western Pacific. In the 1990s, cases were reported in the Torres Strait Islands and in Cape York (mainland Australia). In 2022 and 2023, cases occurred in the Murray and Riverina regions of south-eastern Australian states.
Where JEV is present, people with increased exposure to mosquitoes are at higher risk of infection, particularly those spending time outdoors or working with pigs. Children under 5 years of age and older people who are infected with JEV are at higher risk of more severe illness, including encephalitis.
预防
物理障碍
Preventing mosquito bites with physical barriers is the most effective way to avoid infection with JEV. Exposure to mosquito bites can be prevented by:
- 在户外时穿着长而宽松的衣服
- 使用含有派卡瑞丁或避蚊胺的驱蚊剂
- 如果蚊子很多，限制户外活动
- 使用苍蝇喷雾剂、蚊香和插入式驱虫装置
- 如果您的窗户上没有飞线纱窗或睡在未经处理的帐篷/户外，请睡在经过杀虫剂处理的蚊帐下。
疫苗
Vaccines are also available to prevent the development of 疾病。 There are currently two JE vaccines available in Australia: 伊莫耶夫 杰派克. Vaccination is recommended for:
- all research laboratory workers at risk of exposure to JEV
- travellers spending 1 month or more in areas outside of Australia with endemic JEV transmission
- people who live or work in the outer islands in the Torres Strait (for a cumulative total of 30 days or more) during the wet season (December to May).
Other individuals with specific risk factors are prioritised and funded to receive vaccines through state-led programs:
Table 1: Vaccine brands and dose recommendations
| 疫苗品牌 | 年龄 | Dose and route | 初级课程 | 助推器 |
| 伊莫耶夫 | ≥ 9 months – < 18 years | 0.5 mL subcutaneous (SC) | 1剂 | 1–2 years after primary course if ongoing risk of exposureΩ |
| ≥ 18 岁 | 0.5 mL SC* | 1剂 | NA | |
| JEspect^ | ≥ 2 months – < 3 years | 0.25 mL intramuscular (IM) | 2 doses, at least 28 days apart | 1–2 years after primary course if ongoing risk of exposureΩ |
| ≥ 3 years – < 18 years | 0.5 mL 我是 | |||
| ≥ 18 岁 | 0.5 mL 我是 | 2 doses, at least 28 days apart# |
shaded boxes indicate live-attenuated vaccines, which are contraindicated for 孕妇 and people who are 免疫功能低下.
* Intradermal (ID) administration of Imojev (single dose of 0.1 mL) may be used as a dose-sparing strategy for heatlhy adults (non-pregnant, non-breastfeeding, no immunocompromise) aged ≥ 18 years in circumstances where public health benefits outweigh potential risk as determined by State/Territory health authorities.
^JEspect is an inactivated vaccine and is therefore suitable for administration in pregnant women or immunocompromised individuals.
# The interval between doses of JEspect can be shortened to 7 days for those aged ≥ 18 years, if the individual is at imminent risk of JEV exposure.
Ω Where possible the same brand of vaccine should be used for the booster dose as the primary course. Based on first prinicples, use of the alternate brand should provide a satisfactory immune response however there are no studies confirming this.
副作用
Expected side effects following either vaccine are usually mild and short lived. They can include injection site pain, redness and swelling, as well fever, headaches and muscle aches.
资源
作者： Rachael Purcell（皇家儿童医院免疫研究员）、Nigel Crawford（默多克儿童研究所 SAEFVIC 主任）、Rachael McGuire（MVEC 教育护士协调员）和 Raffaela Armiento（维多利亚州免疫专家服务儿科医生顾问）
审阅者：Rachael McGuire（MVEC教育护士协调员）
日期： October 2024
本章节内的材料将随着新信息和新疫苗的出现而进行更新。墨尔本疫苗教育中心（MVEC）职员定期审阅材料的准确性。
本站点的信息并非针对你个人健康或你家人个人健康的特定、专业的医疗建议。对于医疗方面的问题，包括有关免疫接种、药物治疗和其他治疗的决定，你务必咨询医疗保健专业人士。