1
00:00:01,839 --> 00:00:09,219
There are a lot of viruses out there that
can infect humans, but two things that can
很多病毒會感染人類
但真正可怕的是
2
00:00:09,219 --> 00:00:14,610
get really alarming is when a virus spreads
quickly and when it causes serious harm. Zika
可以快速散播,殺傷力強的病毒
3
00:00:14,610 --> 00:00:18,280
virus has the potential to do both of these
things, which is why it’s gotten a lot of
茲卡病毒恰好就是這樣
因此特別受到關注。
4
00:00:18,280 --> 00:00:23,020
attention. Given this, it makes sense to understand
a bit about Zika virus and the disease it
我們就來介紹茲卡病毒的成因
5
00:00:23,020 --> 00:00:24,930
causes.
以及它所引發的病症。
6
00:00:24,930 --> 00:00:30,490
Zika virus is an arbovirus, meaning it’s
transmitted via certain arthropods, specifically
茲卡病毒是蟲媒病毒
由節肢動物傳染,
7
00:00:30,490 --> 00:00:35,000
mosquitos, so it’s a mosquito-borne virus.
Mosquito-borne doesn’t mean that the virus
尤其是蚊子。
8
00:00:35,000 --> 00:00:39,760
is “born” in the mosquito, though, but
it’s “borne”, with an ‘e’, which
病毒不是由蚊子產生
9
00:00:39,760 --> 00:00:45,110
means carried or transported. Sometimes we
call organisms like this “vectors”, where
而是由蚊子傳播,
所以蚊子稱為病媒動物。
10
00:00:45,110 --> 00:00:49,629
all they do is transport the virus. So with
Zika virus, just like other mosquito-borne
除了茲卡病毒以外,
蚊子傳播的病毒
11
00:00:49,629 --> 00:00:55,510
viruses like dengue fever, yellow fever, Japanese
encephalitis, and West Nile virus, the mosquito
還包括登革熱、黃熱病、日本腦炎
和西尼羅河病毒。
12
00:00:55,510 --> 00:01:00,219
acts as a vector that transmits the virus
from one person to the next. These viruses
蚊子四處傳播的這些病毒
13
00:01:00,219 --> 00:01:03,500
are all in the genus flavivirus.
都屬於黃病毒。
14
00:01:03,500 --> 00:01:10,020
In order to mature her offspring, female mosquitoes
need a blood-meal, which they get from unsuspecting
為了繁殖,雌蚊需從宿主身上
吸食大量血液補充體力。
15
00:01:10,020 --> 00:01:13,969
hosts. Mosquitoes find their blood-meals using
chemical compounds that we and other organisms
蚊子要找到宿主吸血
得靠宿主身上排出的化合物
16
00:01:13,969 --> 00:01:20,039
give off, like carbon dioxide, ammonia, lactic
acid, and octenol. So when a mosquito that
例如二氧化碳、氨、
乳酸,和辛烯醇。因此,
17
00:01:20,039 --> 00:01:25,189
also happens to be carrying the virus finds
her meal and digs in, the virus infects the
帶病毒的蚊子找到目標
叮咬後,病毒便由此感染
18
00:01:25,189 --> 00:01:31,219
human host and starts to multiply or reproduce
within the human. With most flaviviruses though,
並在人的體內繁殖。
多數的黃病毒
19
00:01:31,219 --> 00:01:35,569
the virus isn’t able to replicate enough
in the human host to actually be able to reinfect
在人體內繁殖速度不夠快
不會傳給另一只蚊子,
20
00:01:35,569 --> 00:01:42,889
another mosquito, and so the human is considered
a dead-end-host. However, the Zika virus,
所以人是病毒的最終宿主。
不過茲卡病毒
21
00:01:42,889 --> 00:01:47,859
along with yellow and dengue fever, is well
enough adapted to human hosts such that they
跟黃熱病和登革熱一樣
容易適應人的體質,
22
00:01:47,859 --> 00:01:53,079
can multiply to a point where it can re-infect
another unsuspecting mosquito, which can then
所以繁殖迅速,
足以傳給另一只蚊子
23
00:01:53,079 --> 00:01:58,569
go on to infect more people. This window lasts
for the first week of infection, during which
再傳給其他的人。
關鍵的階段就在感染後第一週,
24
00:01:58,569 --> 00:02:02,609
the Zika virus can be found in the blood.
So if humans with the disease can transmit
這時候病毒就在患者血液裡
很容易再傳回給蚊子,
25
00:02:02,609 --> 00:02:06,819
back to mosquitoes then you can imagine that
areas where there’re a lot of mosquitoes,
可想而知蚊子多的地方
26
00:02:06,819 --> 00:02:10,679
would be a set-up for spreading the virus
super quickly, right?
就是病毒最容易傳播的地方。
27
00:02:10,679 --> 00:02:16,129
Now the Zika virus is transmitted via mosquitos
in the Aedes genus. These blood thirsty little
茲卡病毒是以黑斑蚊為媒介。
這些愛吸血的小東西
28
00:02:16,129 --> 00:02:22,159
guys can bite at night, but are mostly active
during the daytime. Aedes mosquitoes are also
夜裡會叮人,白天更活耀。
黑斑蚊除了傳染茲卡病毒,
29
00:02:22,159 --> 00:02:29,500
the same ones that transmit Chikungunya fever
and dengue fever. When Aedes aegypti or Aedes
也傳染屈公病和登革熱。
能傳染病菌的黑斑蚊有兩種,
30
00:02:29,500 --> 00:02:35,150
albopictus, both species of Aedes mosquito,
lands on your skin and sticks in it’s long
就是白紋伊蚊或埃及斑蚊。
31
00:02:35,150 --> 00:02:39,680
nose—or proboscis, it pierces the epidermis
which is the topmost layer, composed almost
它們以長喙刺穿表皮吸血,
32
00:02:39,680 --> 00:02:45,489
entirely of keratinocytes. Keratinocytes basically
serve to protect against foreign pathogens,
表皮是角質細胞組成的,
可以抵擋病原體,
33
00:02:45,489 --> 00:02:49,980
and it’s typically pretty good at that.
That proboscis though keeps going into the
通常可以有效防止病菌侵入。
但蚊子的喙卻能穿入真皮層,
34
00:02:49,980 --> 00:02:54,400
dermis, since the epidermis just gets oxygen
from the air and doesn’t have its own blood
因為表皮沒有血管,
能從空氣中直接吸收氧氣,
35
00:02:54,400 --> 00:02:58,819
supply, whereas the dermis does, and this
is what our mosquito’s after, right, the
真皮才有血管,
這才是蚊子的下手的目標。
36
00:02:58,819 --> 00:03:04,249
blood meal. Since the proboscis goes through
both the epidermal and dermal layers, the
既然黑斑蚊的喙
能穿透表皮和真皮,
37
00:03:04,249 --> 00:03:10,200
cells in those layers are susceptible to infection
by Zika virus. So in addition to keratinocytes,
這兩層的細胞都易感茲卡病毒。
研究更發現除了角質細胞以外,
38
00:03:10,200 --> 00:03:15,140
fibroblasts, and dendritic cells have also
been found to be permissive to Zika virus,
成纖維細胞和樹狀細胞也
很容易感染上茲卡病毒,
39
00:03:15,140 --> 00:03:19,170
meaning they have some sort of receptor or
attachment site that basically says, here
因為這些細胞表層
都有某種受體或連結位置
40
00:03:19,170 --> 00:03:22,239
you go man, come on in.
可以讓病毒長驅直入。
41
00:03:22,239 --> 00:03:26,
Now we still don’t know everything about
the Zika virus infection, but we do know that
目前我們對茲卡病毒感染症
還不了解,但我們知道
42
00:03:26,340 --> 00:03:32,040
when it enters the cell, it injects a single-stranded
positive RNA strand. Positive means that this
當它進入細胞時會注入
正單鏈RNA。正單鏈和
43
00:03:32,040 --> 00:03:36,989
piece of RNA’s a lot like our own mRNA;
it’s basically ready to rock and get translated
體內的mRNA很相似,
可以直接被轉譯為
44
00:03:36,989 --> 00:03:43,969
into proteins. The virus’s genome is translated
by our own cellular machinery into more viruses.
蛋白質。病毒基因組透過
細胞機制製造更多病毒
45
00:03:43,969 --> 00:03:49,069
Eventually those cells-turned-virus-making-factories
die, which actually ends up releasing more
最終受感染的細胞會
凋亡,釋放更多
46
00:03:49,069 --> 00:03:52,930
viruses to infect more cells.
病毒去感染其他細胞。
47
00:03:52,930 --> 00:03:56,870
As bleak as all that sounds, our immune system’s
actually pretty good at fighting off Zika
雖然聽起來很黯淡,但事實上
我們的免疫系統是善於對抗
48
00:03:56,870 --> 00:04:02,279
virus, and only 1 in 5 get sick from infection,
and the often the others won’t even notice
茲卡病毒,只有五分之一被感染者
會發病,其餘的甚至不會發現
49
00:04:02,279 --> 00:04:07,879
they’ve been infected. Common symptoms when
patients have them, are mild fever and skin
自己被感染了。普遍的病狀
是輕度發熱和起皮疹,
50
00:04:07,879 --> 00:04:12,749
rash, but some also experience muscle and
joint pain, headaches, and conjunctivitis,
但有些人會感受到肌肉和關節
痠痛、頭痛、結膜炎
51
00:04:12,749 --> 00:04:18,940
or red eyes. The incubation period, or time
from infection to symptoms isn’t known,
或紅眼。我們還不知道從感染
到症狀出現需要多長時間,
52
00:04:18,940 --> 00:04:23,180
but it’s thought to be from a few days to
a week.
但通常潛伏期維持在為數天
到一個禮拜。
53
00:04:23,180 --> 00:04:27,080
Treatment usually just involves treating the
symptoms, things like getting plenty of rest,
治療方法通常只能對症下藥
例如多休息
54
00:04:27,080 --> 00:04:31,870
drinking fluids to prevent dehydration, and
taking medicine like acetaminophen to help
多喝水避免脫水
和服用類似乙酰氨酚的藥物
55
00:04:31,870 --> 00:04:34,550
reduce pain and fever.
幫助減輕疼痛和退燒。
56
00:04:34,550 --> 00:04:38,270
Okay so we’ve hit the “spreads quickly”
part, which really matters most in places
說完茲卡病毒在蚊子多
的地方快速傳播後,
57
00:04:38,270 --> 00:04:43,580
with lots of mosquitoes, but what about the
“causes serious harm” part? Well, although
我們來解釋這病毒
的殺傷力了。
58
00:04:43,580 --> 00:04:49,090
it causes mild symptoms in adults, there’s
more to the story. In October 2015, in areas
雖然成人感染後影響較輕
但這不是小問題。2015年10月,
59
00:04:49,090 --> 00:04:53,750
of Brazil where Zika virus has been circulated
quite a bit, public health officials noticed
茲卡病毒在巴西部分地區快速傳染
公共衛生官員注意到
60
00:04:53,750 --> 00:04:58,710
a significant increase in babies born with
microcephaly, which is when a child is born
嬰兒罹患小腦症的數據明顯增加
也就是嬰兒出生時頭部)
61
00:04:58,710 --> 00:05:04,090
with an abnormally small head and therefore
abnormally small brain size; this has the
特別小,也因此影響到
腦部大小。這會導致
62
00:05:04,090 --> 00:05:09,270
tendency to cause serious neurological and
intellectual deficits, seizures, as well as
神經功能和智能上
有缺陷、癲癇,
63
00:05:09,270 --> 00:05:14,020
vision or hearing problems. It was noticed
that there was a huge increase in babies with
和視覺或聽覺的障礙。
目前在當地新生兒患有
64
00:05:14,020 --> 00:05:20,590
microcephaly—up to a 20-fold increase—among
Brazilian states with Zika virus outbreak.
小腦症比例已增加了二十倍。
65
00:05:20,590 --> 00:05:25,560
As of November 2015, the European Center for
Disease Control has stated that it’s plausible
到2015年11月為止,
歐洲疾病預防控制中心已經聲明
66
00:05:25,560 --> 00:05:31,060
the Zika virus is able to cause microcephaly
in the developing fetus or newborn, as the
茲卡病毒是可能造成
胎兒或新生兒患有小腦症,因為
67
00:05:31,060 --> 00:05:35,080
Zika virus can be transmitted from mother
to baby during pregnancy or around the time
茲卡病毒會經由孕婦
傳染給胎兒,
68
00:05:35,080 --> 00:05:40,620
of birth, although it’s not yet known how
often this happens or how exactly the Zika
但是現在還不能確定
類似病情的發生機率
69
00:05:40,620 --> 00:05:42,620
virus is linked to microcephaly.
以及和小腦症的直接關聯。
70
00:05:42,620 --> 00:05:49,620
In addition to being spread mostly by mosquito
bites, and in some cases from mother to child,
除了透過蚊蟲叮咬
和經由母體傳給胎兒散播病菌,
71
00:05:49,620 --> 00:05:54,560
Zika virus has also been reported to spread
through both blood transfusions and sexual
茲卡病毒也被報導能藉由
血液和性接觸傳染病菌。
72
00:05:54,560 --> 00:05:55,479
contact.
73
00:05:55,479 --> 00:06:00,940
Currently, there’s no vaccine for Zika virus,
so it’s highly advised to take precautions
目前還沒有疫苗能對抗茲卡,
所以強烈建議大眾提高警覺。
74
00:06:00,940 --> 00:06:06,370
when traveling to areas of outbreak, mostly
limiting mosquito bites, so doing things like
到病情嚴重地區旅遊
盡可能減少被蚊子叮咬的機率
75
00:06:06,370 --> 00:06:10,960
wearing bug spray all day, or wearing long-sleeve
shirts and pants, especially during the day
像隨身攜帶防蚊液或穿長袖
衣褲,特別在一天中
76
00:06:10,960 --> 00:06:15,580
when the Aedes mosquitoes are most active.
If infected, it’s especially important to
黑斑蚊最活躍的時候。
如果被感染了,趕快避開
77
00:06:15,580 --> 00:06:20,650
avoid mosquitoes to avoid spreading Zika virus
to others, especially in that first week of
蚊子多的地方,避免蚊子
再將病毒傳染給他人,尤其是
78
00:06:20,650 --> 00:06:25,819
symptoms. The World Health Organization currently
suggests pregnant women consult their doctor
出現症狀的第一週。WHO
建議懷孕婦女諮詢其主治醫生
79
00:06:25,819 --> 00:06:33,629
or travel clinic for guidance and recommendations.
或向旅遊診所尋求幫助。