According to the study, the spread of HIV can be slowed through ______.

A．reducing the amount of the virus in a person’s blood

B．improving people's immune system

C．reducing other sexually transmitted diseases

D．new anti-viral drugs

CJD can probably only be transmitted between humans through blood contact.

A．Y

B．N

C．NG

A．H. pylori

B．Peptic ulcers

C．Bacterium

D．Stomach cancer

A．Y

B．N

C．NG

HIV and Its Transmission

Research has revealed a great deal of valuable medical, scientific, and public health information about the human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). The ways in which HIV can be transmitted have been clearly identified. Unfortunately, false information or statements that are not supported by scientific findings continue to be shared widely through the Internet or popular press. Therefore, the Centers for Disease Control and Prevention (CDC) has prepared this fact sheet to correct a few misperceptions about HIV.

How HIV Is Transmitted

HIV is spread by sexual contact with an infected person, by sharing needles (primarily for drug injection) with someone who is infected, or, less commonly, through transfusions of infected blood or blood clotting factors (凝血因子). Babies born to HIV-infected women may become infected before or during birth or through breast-feeding after birth.

Some people fear that HIV might be transmitted in other ways; however, no scientific evidence supporting any of these fears has been found. If HIV were being transmitted through other routes (such as through air, water, or insects), the pattern of reported AIDS cases would be much different from what has been observed. For example, if mosquitoes could transmit HIV infection, many more young children and preadolescents would have been diagnosed with AIDS.

All reported cases suggesting new or potentially unknown routes of transmission are thoroughly investigated by state and local health departments with the assistance, guidance, and laboratory support from CDC. No additional routes of transmission have been recorded, despite a national sentinel (監(jiān)測(cè)) system designed to detect just such an occurrence.

The following paragraphs specifically address some of the common misperceptions about HIV transmission.

HIV in the Environment

Scientists and medical authorities agree that HIV does not survive well in the environment, making the possibility of environmental transmission remote. HIV is found in varying concentrations or amounts in blood, semen (精液), vaginal (陰道的) fluid, breast milk, saliva (唾液), and tears. To obtain data on the survival of HIV, laboratory studies have required the use of artificially high concentrations of laboratory-grown virus. Since the HIV concentrations used in laboratory studies are much higher than those actually found in blood or other specimens, drying of HIV-infected human blood or other body fluids reduces the theoretical risk of environmental transmission to that which has been observed—essentially zero. Incorrect interpretation of conclusions drawn from laboratory studies has unnecessarily alarmed some people.

Results from laboratory studies should not be used to assess specific personal risk of infection because: (1) The amount of virus studied is not found in human specimens or elsewhere in nature, and (2) no one has been identified as infected with HIV due to contact with an environmental surface. Additionally, HIV is unable to reproduce outside its living host except under laboratory conditions. Therefore, it does not spread or maintain infectiousness outside its host.

Households

Although HIV has been transmitted between family members in a household setting, this type of transmission is very rare. These transmissions are believed to have resulted from contact between skin or mucous membranes (黏膜) and infected blood. To prevent even such rare occurrences, precautions should be taken in all settings "including the home" to prevent exposure to the blood of persons who are HIV infected, at risk for HIV infection, or whose infection and risk status are unknown, For example.

Gloves should be worn during contact with blood or other body fluids that could possibly contain vis

A．Y

B．N

C．NG

AIDS is the fifth leading cause of death among persons between ages 25 and 44 in the United States. About 47 million people worldwide have been infected with HI~ since the start of the epidemic.

AIDS stands for "Acquired Immune Deficiency Syndrome". It is caused by the Human Immunodeficiency Virus(HIV). AIDS is the final and most serious stage of HIV disease, in which the signs and symptoms of severe immune deficiency have developed.

HIV has been found in saliva, tears, nervous system tissue, blood, semen, vaginal fluid, and breast milk. However, only blood, semen, vaginal secretions, and breast milk have been proven to transmit infection to others.

Transmission of the virus occurs through sexual contact, blood transfusions or needle sharing, and from mother to child. A pregnant woman can passively transmit the virus to her fetus, or a nursing mother can transmit it to her baby.

Other transmission methods are rare and include accidental needle injury, artificial insemination through donated semen, and through a donated organ.

HIV infection is not spread by casual contact such as hugging and touching, by touching dishes, doorknobs, or by mosquitoes. It is not transmitted to a person who donates Blood or organs. However, it can be transmitted to the person receiving blood or organs from an infected donor. This is why blood banks and organ donor programs screen donors' blood and tissues thoroughly.

How many people worldwide have been infected with HIV since the start of the epidemic？

A．47 million.

B．4 billion.

C．25 million.

D．44 million.

The virus is transmitted most commonly through ______.

A．programs sent by modem

B．shrink-wapped retail software

C．piracy of software

D．the use of floppy disks

A、To learn about how HIV is transmitted

B、To practice safer sex

C、To get a HIV test

D、To take steps to avoid becoming infected or infecting others