But with 35 million people currently infected, what exactly is it, and are we close to a cure?

但是，目前有3千5百萬人感染愛滋病，愛滋病到底是什麼，我們快找出治療的辦法了嗎？

To contract HIV, the virus must enter the bloodstream - and it's often transmitted

感染愛滋病，病毒必須進入血液中－這通常是

from infected bodily fluids like blood, semen, vaginal fluids or breast milk.

輸送感染的體液像是血液，精液，陰道液或是母奶

Once inside the bloodstream, HIV targets a variety of cells, but most specifically the T-helper cells (CD4),

一旦進入血液，愛滋病毒便會鎖定不同種類細胞，尤其是T-helper細胞(CD4)

which are a type of white blood cell that play an essential role in our immune system and fighting infections.

它是白血細胞的一種，在我們的免疫系統裡主要扮演著抵抗感染的角色

The outer envelope of HIV is covered in glycoproteins

愛滋病毒的外包膜覆蓋著糖蛋白

which mutate frequently, ultimately tricking the T-cell receptors to not recognize the virus.

最終唬弄過T細胞的感受器以致無法辨認出病毒

Once attached to specific proteins on the T-cell, it begins to fuse the membranes together,

病毒一旦附著在T細胞特定的蛋白質上，便會開始和細胞膜融合

and eventually enters the cell where it releases 2 viral RNA strands and 3 essential replication enzymes.

最後進入細胞釋放2種濾過性毒菌核糖核酸鏈和3種基本複製酶

Because HIV is a retrovirus, the RNA is transcribed into DNA, represented here by a zipper of two RNA strands transcribing into DNA.

由於愛滋病毒是反向病毒，所以RNA被轉錄為DNA，在這裡以拉鍊代表兩條RNA轉錄為DNA

This DNA is then integrated into the host cell’s genome.

這個DNA便和宿主細胞的基因組結合為一體

This makes the T-cells treat the viral genes like their own, which causes

這讓T細包對待這個濾過性病菌基因有如自家人一般，導致

them to make more copies of the virus. These then leave the host cell and mature, ultimately

它們複製更多的病毒。病毒接著離開宿主並且發育成熟，最終

seeking more T-cells. The virus is particularly difficult to treat because its mutation rate

尋找更多的T細胞。治療這種病毒格外困難，因為它突變速度太

is so high. Overall the replication process creates more than 10 billion new virions each day.

快。全部複製的程序在一天內可以產生超過100億個新的病毒體

During these initial stages of replication, called the latency period, a person may not

在複製的初始階段期間，稱之潛伏期，感染者不會

show any major symptoms for up to 8 years. If not treated, the HIV eventually kills off

表現出任何主要症狀，這段期間可長達八年。如未治療，愛滋病毒最終會殺死

the specific T-cells it infects. When these T-Cells fall below 200 cells per cubic millimeter of blood,

被它感染的特定T細胞。當血液中的T細胞低於每立方毫米200個

it becomes Acquired Immune Deficiency Syndrome or AIDS.

便成為後天免疫缺乏症候群，我們俗稱的愛滋病

After progressing this far, the immune system becomes suppressed is much more susceptible

經過這段時間的發展，免疫系統受到抑制而容易罹患癌症

to cancers and opportunistic infections such as pneumonia. A person doesn't die from AIDS

和機會性感染如肺炎等，患者並不是死於愛滋病

they actually die from an illness that the body could not fend off.

而是其他身體無法抵抗的疾病

Nowadays there is medicine that helps fight these opportunistic infections, like Daraprim

如今已有對抗這些機會性感染的藥物，像是達拉匹林

(which was recently in the news when Martin Shkreli of Turing Pharmaceutical decided to

（最近因為圖靈製藥公司的馬丁謝克雷利將

raise the price from $13.50 - $750 per pill.. There are also anti-retroviral drugs that

達拉匹林每顆價錢由美金13.50元哄抬至美金750元而躍上新聞版面。）也有抗逆轉病毒藥物

slow the virus down by blocking certain enzymes which are required for the virus to multiply.

藉由攔阻某些有助於病毒倍增的酶，來延緩病毒侵略

Similarly, those without HIV but at high risk of contracting the virus may take pre-exposure

同樣的，那些沒有得到愛滋病毒但卻處於感染高風險的情況也可以服用暴露前預防投藥

prophylaxis or PrEP. This works similar to antiretroviral drugs by blocking the enzyme reverse transcriptase.

也稱之為PrEP. 它的功效和抗逆轉病毒藥物相似，用來阻擋逆轉錄酶

Thankfully there is hope for a cure - a small population of people are immune to the HIV virus

感謝上天我們有希望得到解藥－有一小部分的人對愛滋病毒免疫

because of a mutation linked to the T-cells. In one case, an HIV-positive subject

這和他們T細胞的突變有關。在一個例子中，一位愛滋病毒陽性患者

received a bone marrow transplant, meaning they were given new stem cells that generate

接受骨髓移植手術，這代表他被賦予新的幹細胞可以產生

different T-cells, and within 20 months there was no evidence of the virus in their bloodstream.

不同的T細胞，在20個月之內，他的血液中就完全找不到病毒了

Though this is very indivisualized medicine, it certainly opens up the possibilities of

儘管這是特殊的個別治療，它的確開啟製造

generating HIV resistant cells. Combine this with other therapies and preventative measures

抵抗愛滋病毒細胞的可能性，結合這個方式加上其他療法以及預防措施

like condoms, clean needle programs and safe blood transfusions, and HIV/AIDS may one day

如保險套，乾淨針頭計畫和安全血液輸送，如此一來後天免疫缺乏症候群/愛滋病或許有一天

be a thing of the past.

能夠成為過去式

Your sharing of this video is much appreciated, in the effort to help spread knowledge and awareness.

感謝你分享此影片，讓我們一起為幫助推廣知識及意識而努力

Special thanks to audible for supporting this episode to give you a free 30 day trial at

特別感謝audible贊助本集節目讓觀眾可以有免費30天體驗

audible.com/asap. This week we wanted to recommend the book Redefining Reality, which explores

audible.com/asap. 這禮拜我們想要推薦的是Redefining Reality，它是

what is real and what’s illusory from both a scientific and philosophical perspective,

一部集結一系列精彩演講，從科學及哲學兩種角度探索真實和虛幻的書，

through a series of really awesome lectures. You can get a free 30 day trial at audible.com/asap

你可以得到30天audible.com/asap的免費體驗

and choose from a massive selection! We love them as they are great when you’re on the go.

然後從眾多選項裡挑選！我們愛它因為當你在外奔走時它是很棒的伴侶

And subscribe for more weekly science videos!

也請訂閱更多周刊的科學視屏！