伊波拉病毒回歸：回到第一方

http://www.thelancet.com/infection Vol 2022 年 11 月 22 日

圖片來源：Nicholas Kajoba – Xinhua News Agency – PA Images

當世界仍在應對 COVID-19 大流行並面臨猴痘大流行等意想不到的挑戰時，一個老敵人在非洲再次出現。 9 月 20 日，烏干達報告了自 2012 年以來的首例伊波拉病毒病例，當時確認一名 24 歲男子因伊波拉病毒感染呈陽性住院，並出現各種症狀，包括高燒、強直性抽搐、血液嘔吐物和腹瀉染色，眼睛出血。該病例只是第一例，截至 10 月 5 日，該國已報告 63 例伊波拉病毒病確診和疑似病例。到目前為止，已有29人死亡。疫情始於穆本德區，現已蔓延至其他四個區：卡桑達、凱格瓦、本揚加布和現在的卡加迪。疫情中心穆本德位於連接烏干達首都坎帕拉和剛果民主共和國的主要公路沿線，靠近基巴萊國家公園，深受前往烏干達黑猩猩觀賞的外國遊客的歡迎。此外，在穆本德附近有幾個難民安置點，為烏干達 1,500 萬難民中的至少 20 萬提供住所。因此，擔心的是，如果伊波拉病毒到達人口稠密地區或感染前往其他國家的旅行者，控制疫情將變得異常困難。剛果民主共和國、肯亞、盧旺達、蘇丹和南蘇丹已開始對越過烏干達邊境的旅客進行伊波拉病毒病症狀篩查。美國還將開始對過去 21 天曾在烏干達入境的旅客進行篩查。

雖然最近剛果民主共和國也發生了其他伊波拉病毒病疫情，但烏干達目前的疫情尤其令人擔憂的是，它是由蘇丹伊波拉病毒株引起的，而最近的所有暴發都是由薩伊病毒株引起的。薩伊伊波拉病毒與蘇丹伊波拉病毒的基因差異大約為 40%。這種差異對預防和治療具有重大意義，因為迄今為止開發的所有疫苗或治療方案僅適用於薩伊毒株。

伊波拉病毒病疫苗和藥物開發方面取得的大部分進展源於 2013 年至 2016 年的西非疫情，這是迄今為止報告的最大一次疫情，導致 11,323 人死亡。就對診斷工具、治療方案和實用管理指南的關注和投資而言，這次疫情是一個分水嶺，導致伊波拉病毒疫苗和藥物獲得許可，並在患者管理方面取得重大進展，例如開發了「伊波拉立方病房」(Ebola Cube)，一個生物安全的緊急治療單元，讓醫護人員能夠在沒有感染風險的情況下照顧病人。

目前在烏干達，人們擔心醫護人員之保護。到目前為止，其中四人已經死亡，由於缺乏有效的疫苗和足夠的個人防護設備，醫護人員照顧病人的風險不容小覷。國際社會必須支持烏干達採取一切可用措施來控制疫情。世衛組織秘書長譚德塞表示，他們已從緊急應急基金中撥出 200 萬美元，並正與合作夥伴一起派遣更多專家、物資和資源，以遏制該疾病的傳播。譚德塞主張盡快在烏干達開展疫苗和療法試驗。有一些疫苗正在開發中，可以對抗蘇丹毒株，但它們仍處於測試的早期階段。

更複雜的是，烏干達剛剛擺脫 COVID-19 造成的破壞，現在正面臨克里米亞-剛果出血熱的爆發。由於伊波拉病毒病的初始症狀與該地區其他流行疾病的症狀相似，因此透過試驗進行快速診斷變得具有挑戰性。問題在於，考慮到伊波拉病毒病的高傳染性和致死性，漏掉任何一個病例都會危及疫情控制。

了解迄今為止報告的伊波拉病毒病例的傳播鏈並識別潛在的超級傳播事件，例如葬禮，對於識別所有感染至關重要。提倡社區參與和分散照護方法。伊波拉治療單元的設計需要包括所有最新進展，並且需要加強醫療保健系統的支持。可悲的是，蘇丹伊波拉病毒勢必會爆發，因此現階段缺乏針對該病毒開發的疫苗或治療劑代表了國際社會的重大疏忽，可能導致許多人喪生。 ■ 刺胳針傳染病

Ebola returns: back to square one

http://www.thelancet.com/infection Vol 22 November 2022

While the world is still dealing with the COVID-19 pandemic and facing unexpected challenges, such as the monkeypox pandemic, an old enemy has reappeared in Africa. On September 20, Uganda reported its first case of Ebola virus disease since 2012 when positivity for Ebola virus infection was confirmed for a 24-year-old man hospitalised with a wide range of symptoms, including high-grade fever, tonic convulsions, blood-stained vomit and diarrhoea, and bleeding in the eyes. This case was only the first one and as of October 5, sixty-three confirmed and probable cases of Ebola virus disease have been reported in the country. So far, there have been 29 deaths. The outbreak started in the Mubende district, and the disease has now spread to four other districts: Kassanda, Kyegegwa, Bunyangabu, and now Kagadi. Mubende, the centre of the outbreak, lies along a major highway connecting Uganda’s capital, Kampala, with the Democratic Republic of Congo, and it is close to the Kibale National Park, popular with foreign tourists going to see Uganda’s chimpanzees. Moreover, near Mubende there are several refugee settlements, housing at least 200 000 of Uganda’s 1·5 million refugees. So, the fear is that if Ebola virus reaches a densely populated area or infects travellers going to other countries, controlling the outbreak will become extremely difficult. DR Congo, Kenya, Rwanda, Sudan, and South Sudan have started screening travelers crossing their borders with Uganda for Ebola virus disease symptoms. The USA will also start screening passengers entering the country who have been in Uganda in the previous 21 days.

While other Ebola virus disease outbreaks have occurred recently in the Democratic Republic of Congo, what makes the current Ugandan outbreak particularly concerning is that it is caused by the Sudan strain of Ebola virus, whereas all recent outbreaks had been caused by the Zaire strain. Zaire Ebola virus is roughly 40% different genetically from Sudan Ebola virus. This difference has major implications for prevention and therapy because all vaccines or therapeutic options developed so far only work for the Zaire strain.

Most of the progress made in terms of vaccine and drug development for Ebola virus disease has stemmed from the west African outbreak in 2013–2016, the largest one reported so far that caused the death of 11323 people. That outbreak has been a watershed in terms of attention and investment towards diagnostic tools, therapeutic options, and practical management guidelines, leading to the licensing of Ebola virus disease vaccines and drugs and major improvements in patient management, such as the development of the ‘Ebola Cube’, a biosecure emergency treatment unit that allows healthcare workers to care for patients without risk of infection.

In Uganda at the moment there is concern about protecting healthcare workers. Four of them have died so far and in absence of an effective vaccine and with shortage of adequate protective personal equipment, the risk for healthcare workers looking after patients cannot be downplayed. It will be essential that the international community supports Uganda in deploying all available measures to control the outbreak. WHO chief Tedros Adhanom Ghebreyesus said that they have released US $2 million from the Emergency Contingency Fund and are working with their partners to send additional experts, supplies, and resources to curb the spread of the disease. Tedros advocated for trials of vaccines and therapies to start soon in Uganda. There are vaccines in development that could work against the Sudan strain but they are still in the early stages of testing. 

To complicate things further, Uganda is just emerging from the havoc created by COVID-19 and is now facing an outbreak of Crimean-Congo haemorragic fever. Because the initial symptoms of Ebola virus disease are similar to those of other diseases endemic in the region, rapid diagnosis through trialling becomes challenging. The problem is that considering the high contagiousness and lethality of Ebola virus disease, missing any case can jeopardise outbreak control. 

Understanding the chain of transmission of the Ebola virus disease cases reported so far and identifying potential superspreading events, such as funerals, is essential to identify all infections. Community engagement and a decentralised care approach is advocated. The design of the Ebola Treatment Units will need to include all most recent advances and strengthening of the healthcare system needs to be supported. Sadly, an outbreak of Sudan Ebola virus was bound to happen so the lack of a vaccine or therapeutic agent developed against it at this stage represents a major oversight of the international community that could cost many lives. ■ The Lancet Infectious Diseases