Epidemiology and Lab Diagnosis of HIV/AIDS在线视频

From now on
现在

we will draw your attention to the
我们一起来学习

epidemiology of HIV/AIDS.
HIV/AIDS的流行病学特征

According to the UNAIDS data,
根据联合国艾滋病规划署的数据

as of 2018，
截至2018年

approximately 37.9 million
全世界大约有3790万人

people worldwide were living with HIV,
感染HIV

amounting to about 5,000 new infections each day!
每日新增感染数高达5000人

Because of prevention campaigns,
得益于现有的防控措施

the data of new infections stabilize.
新增感染数比较稳定

1.7 million new infections are estimated in 2018.
2018年预计约有170万新增感染病例

As the table shows,
如表所示

infection rates vary widely
全球不同地区

in different regions of the world.
HIV感染率不同

The highest rates are in Eastern and Southern Africa
非洲东部和南部感染率最高

with a growing number
亚洲和太平洋地区

of cases in Asia and Pacific regions.
的感染率在不断上升

770,000 people worldwide have died from AIDS,
全球有77万人因AIDS死亡

imposing a great burden to human health.
这给人类健康带来了沉重负担

The transmission routes
目前确认的HIV传播途径

of HIV has been clarified.
有以下几种

The virus is present in blood,
HIV主要在

semen,
无症状携带者和AIDS患者的

and vaginal secretions
血液、精液

of asymptomatic carriers and AIDS patients.
以及阴道分泌物中存在

As you can imagine,
所以

the most common means of transmission
HIV最常见的传播方式

are sexual contact and exposure
是性接触和输入了

to contaminated blood and blood products.
被HIV污染的血液或其他血制品

Vaginal and anal intercourse, blood transfusion,
阴道和肛门性交（性行为）、输血、

needle sharing among drug users are the major
与吸毒者共用针头

sources of transmission.
是主要的传播来源

Tattoo needles and contaminated inks
纹身时使用被HIV污染的针头和墨水

are also potential means for spreading.
也是潜在的传播途径

Additionally,
此外

vertical transmission through intrauterine transmission,
垂直传播包括通过胎盘、

peripartum transmission or breast feeding
产道、或哺乳的方式

are also important routes for infection.
也是HIV传播的另一重要途径

However,
然而

HIV is not transmitted by casual contact
HIV一般不通过日常的接触

like touching and hugging,
如触摸、拥抱

insect bites,
昆虫叮咬

water,
水源

food-sharing, etc.
共享食物等方式传播

What kind of people are at risk?
HIV感染的高危人群有哪些呢？

Intravenous drug users,
静脉药瘾者

sexually active people with multiple partners,
有多个性伴侣的性活跃者

blood and organ transplant recipients
血液和器官移植的接受者

and hemophiliacs,newborns
血友病患者

newborns of infected mothers
母亲是HIV感染者的新生儿

are at highest risk for HIV infections.
他们都是HIV感染的高危人群

Besides,
此外

the presence of other sexually transmitted diseases (STDs)
患有其他性传播疾病（STDs）

also increases the likelihood of transmission.
也会增加HIV感染风险

Now,
现在

there comes a question：
问题来了

how can we identify the infected individuals?
怎么确诊HIV的感染？

In fact,
事实上

identifying and evaluating HIV infection
实验室检查是诊断HIV感染的

through lab tests are very important.
重要方法

There are four reasons to perform labtests:
进行实验室检查的目的有:

1. to identify those living with the infection,
1.诊断HIV感染者

2. to identify carriers who may transmit infection
2.筛查可能携带HIV的个体

to others(specifically blood or organ donors
如血液和器官捐献者

pregnant women, and sex partners),
可能被感染的孕妇或性伴侣

3. to evaluate the course of disease
3.评估疾病病程

and confirm the diagnosis of AIDS,
和诊断AIDS

4. to monitor the efficacy of treatment.
4.监测治疗效果

Several lab tests can be applied.
以下是常用的几种实验室检查方法：

Serology can be used document HIV infection.
血清学检查用来诊断HIV感染情况

Genome detection and viral load
病毒核酸和病毒载量的检测

quantitation is a good indicator
可以用于监测

of the disease course and treatment efficacy.
疾病进展和评价病毒治疗效果

Sometimes,
有时

p24 viral antigen could be also detected.
也可检测p24抗原

T cell subsets analysis including
T细胞亚群分析包括

the absolute number of CD4 T cells
CD4阳性T细胞的数量

and the ratio of CD4 to CD8 can also be determined
CD4和CD8的比例也是有效的检测手段

Nevertheless,
但是

virus isolation is not routinely performed.
病毒分离不用于常规检测

Serology is often used,
虽然无法筛查出新近感染

despite its inability to detect a recent infection.
血清学诊断仍是最常用的检查方法之一

HIV antibodies may develop over 4 to 8 weeks.
人体感染HIV 4-8周后可产生HIV抗体

Enzyme immunoassay(EIA)/Enzyme-linked
酶免疫测定法(EIA)

immunosorbent assay (ELISA) is performed
或酶联免疫吸附试验(ELISA)

for routine screening
用于HIV的常规筛查

Western blot analysis
蛋白质印迹法（Western blot）

is used to confirm seropositive results.
用于确诊血清学检查的阳性结果

The pictures here show you the results
图例展示的是ELISA法

of ELISA and a rapid HIV testing kit
与HIV抗体快速诊断试剂盒

for HIV antibodies in blood or saliva
检测血液和唾液标本的结果

Western blot is a confirmatory assay.
蛋白质印迹法是确诊试验

The Western blot results show
其阳性结果说明

the presence of HIV antibodies.
标本中含有HIV抗体

As the figure presents
如图所示

the most important antibodies
最重要的

are those against the glycoproteins including gp120,
抗糖蛋白抗体包括抗gp120、

gp160 and gp41,
抗 gp160、抗 gp41和

and the viral antigen p24.
抗病毒抗原p24抗体结果阳性

Moreover,
此外

a series of HIV tests on an infected individual
HIV感染者的血清学系列检测

can illustrate the changes of results during
还可显示艾滋病窗口期间

the window period from HIV-negative to HIV-positive.
检查结果的变化（从阴性转为阳性）

Viral load in the blood can be measured by PCR assays.
血液中HIV的病毒载量可用PCR方法进行检测

It is a good indicator
病毒载量是评估预后

for prognosis and antiviral therapy monitoring.
和监测抗病毒治疗效果的重要指标

The figure here reveals
以下图表的结果显示了

the relationship between
病毒载量与

the survival duration and viral load.
患者存活期之间的关系

The viral load predicts the survival time.
病毒载量的高低可用于预测患者生存期

The higher the viral load, the shorter the survival.
病毒载量越高，患者生存期可能越短

With the confirmatory diagnosis,
确诊后

what shall we do next?
我们应该做什么？

In the next session,
下一节课

We will answer the question.
我们再来回答这个问题