猪只也有类似艾滋病的病
在人们还没有从疯牛病和口蹄疫的惊恐中完全恢复过来时，又传来一项令人震惊的消息：猪只也有类似艾滋样的病。这种正在猪中流行的，与艾滋病有很多相似之处的神秘疾病曾被称为“蓝色流产”和“猪不孕症”。现在研究人员称之为“猪生殖及呼吸系统综合征”，简称PRRS。
自八十年代中期以来，该病就成为许多国家的恶梦。专家估计，目前美国有75%的猪只感染PRRS，疫苗仅仅部份有效。
PRRS病毒首先攻击猪的免疫系统，使猪的机体易发生其它感染，特别是肺部感染。部份猪只可以发生慢性感染并且成为病毒携带者而不表现出症状。PRRS病毒经由精液、唾液和血液传播，在一起饲养及用卡车运输时呆在一起的猪只最容易发生感染。PRRS以多样化的症状为特征，经常导致幼猪死亡。疾病会使母猪丧失90%的受孕率(自然流产或是生下来的幼猪已经死亡)，20-30%的幸存猪只日后也可能死于呼吸系统疾病如肺炎
PRRS研究员，美国明尼苏达大学兽医学院的斯哥特·迪说认为，这种猪疾病带来的经济灾难正逐渐扩大。PRRS病毒虽然不属于艾滋病病毒家族的一个成员，但也是损坏免疫系统并且导致机体出现一些类似艾滋病的变化。
, http://www.100md.com
北卡罗来纳州立大学兽医学院的PRRS研究员蒙蒂·姆索的研究发现，感染PRRS的猪只在下列方面与人类艾滋病类似：
1、出现免疫系统功能抑制，继发感染主要发生在肺部；
2、PRRS病毒首先在肺泡巨噬细胞内复制，使患猪容易发生机会感染；
3、免疫系统的淋巴细胞出现与艾滋病类似变化，生产许多高水平的生物化学物质。
但某些幼猪可以从PRRS病毒触发的严重肺感染中幸存下来，这是PRRS和艾滋病在发展方面的显著差别。
尽管这样，研究两者的相似性仍是很重要的。姆索希望通过更多地了解PRRS，从而了解更多人类艾滋病的知识，并且可能发现有助于治疗这两种疾病的方法。
美国国家猪肉制品委员会的科技副总裁贝思·劳特纳说，PRRS是一种复杂的疾病，它的一些症状类似艾滋病。迄今为止，没有证据证明该病毒能通过任何途径(包括食物)感染人类，也没有发现猪肉中有病毒的迹象。因此，不应该产生“猪把艾滋病传给了人”的错误结论。
, http://www.100md.com
姆索、迪、劳特纳都指出，PRRS病毒具有可变性，这增加了利用疫苗控制该病毒的困难。需要更多地了解猪的免疫系统在感染PRRS时是如何运作的，如PRRS会否将猪身上某些尚未被发现的、可潜在传播给人类的微生物释放出来。另外，也要警惕由于将过多的注意力集中在PRRS病毒上，而将这种疾病过份单纯化，也许还有许多因素复合作用诱发了PRRS。
PRRS在许多方面它仍然如此神秘，尽管目前研究取得了一些进展，但人们对PRRS在任何方面都不容过于自信，有必要进行更多的研究以正确处理、有效控制PRRS。
AIDS-Like Symptoms Threaten Pigs
You thought cows and sheep had problems. It seems a disease with some similarities to AIDS is sweeping through pig farms.
, http://www.100md.com
Forget about the current media spotlight on Mad Cow and Foot and Mouth diseases for a moment. Our discovery today is about a disease in pigs that in many ways is like AIDS.
This horrendous disease, at one point called “swine mystery disease”, “blue abortion”, and “swine infertility”, and now referred to as “Porcine Reproductive and Respiratory Syndrome”, or PRRS, has infected some pigs in about 75 percent of American pig herds, according to experts. Vaccines have only partially been effective.
, 百拇医药
The disease also has been creating a nightmare for many other nations since at least the mid-1980s.
Pigs Are Dying
The reproductive and respiratory syndrome, which often kills baby pigs, is characterized by a variety of conditions and is causing economic hardship for pig farmers. Affected mothers lose up to 10 percent of their pregnancies. Their babies are spontaneously aborted or are stillborn. As many as 20 percent to 30 percent of survivors may suffer and die from respiratory disease, such as pneumonia.
, 百拇医药
The PRRS virus is said to primarily attack a pig’s immune system, leaving the body open to a host of other infections, particularly in the lungs. Some pigs develop a chronic infection and become carriers but show no symptoms.
Research reveals that the virus is transmitted via semen, saliva and blood. Those pigs herded closely together and transported at close quarters by trucks may be more susceptible to infection.
To date, there is no evidence that the virus can infect humans from any source, including via food. Researchers looking for signs of the virus in pig meat haven’t found any.
, http://www.100md.com
Scott Dee with the University of Minnesota College of Veterinary medicine, a PRRS researcher, says the disease is the “most economically devastating swine disease there is”, and that the “problem is getting bigger”, but he bristles a little when I introduce the term “AIDS” into the conversation.
I do so because the PRRS virus, while not a member of the family of viruses to which HIV belongs, is also said to strike the immune system and then cause some changes in the body that are similar to AIDS.
, http://www.100md.com
No Virus Trace in People or Meat
Beth Lautner, vice president of science and technology at the National Pork Producers Council, says PRRS is a complex disease, acknowledges that some of the symptoms are AIDS-like and notes that no trace of the disease has been found in people or meat. She worries that “some people will jump to the wrong conclusion, that pigs gave AIDS to humans.”
Monte McCaw, a PRRS researcher with North Carolina State University’s College of Veterinary Medicine, believes that while the differences between PRRS and AIDS are obvious to researchers, it is also important to study the similarities.
, 百拇医药
McCaw has so far been low-key about his AIDS-related findings. I had to initially research farm bulletins, obscure scientific reports and speeches he gave in order to piece some of his views together.
“I am stunned you found this,” he said, after I had almost given up trying to contact him for an interview.
Some Similarities to AIDS
McCaw has concluded that the following key conditions in PRRS-infected pigs are similar to what is found in AIDS:
, 百拇医药
Secondary infections, mainly in the lungs, are common due to the immune-suppressive abilities of the PRRS virus.
PRRS reproduces in cells called macrophages, which are front-line cells in the body*s immune system.
PRRS primarily reproduces in cells called alveolar macrophages, which are immune cells in the lung. Damaging these lung immune cells makes the animal susceptible to opportunistic infections.
, 百拇医药
Key white blood cells of the immune system (lymphocytes) go through some of the same changes that occur in AIDS.
Lymphocytes produce higher levels of a variety of biochemical substances, as in AIDS.
McCaw adds, however, that some baby pigs that manage to survive the onslaught of infections in the lungs that the PRRS virus triggers end up thriving.
“This is an obvious difference in the way (AIDS and PRRS) generally develop,” he says.
, http://www.100md.com
But McCaw thinks enough of the similarities between AIDS and PRRS that he indicated in a report that he would like to study novel immune therapies in pigs. He also told me: “We would hopefully learn more about PRRS in pigs and maybe AIDS in humans,” and to possibly “find ways to help treat both diseases.”
A recent finding in Dee*s camp should further encourage McCaw’s foray into the AIDS-like dimension of this disease. “We have just learned that PRRS can be transmitted from one pig to another via the repetitive use of (vaccination) needles,” Dee says.
, http://www.100md.com
Dee also says that PRRS hides out in the lymph nodes. The same is claimed for HIV.
More Research Necessary
McCaw, Dee and Lautner all agree that much more research will be necessary in order to get a proper handle on PRRS, in the hopes of better understanding and controlling it. They point to the manner in which the PRRS virus is capable of changing and the difficulty this creates for vaccine strategies against the virus.
, 百拇医药
Much more will need to be learned about how the pig’s immune system behaves in PRRS. Will PRRS, for example, be capable of unleashing some previously undetected microbe in pigs that could potentially be transmitted to humans?
Or, for that matter, is this pig disease being oversimplified by focusing so much of the attention on the PRRS virus? There may well be a number of factors that initially combine to trigger PRRS. The disease has often been referred to as a “mystery,” and in many ways it remains so.
While progress has been made, no one should be overconfident about any aspect of this terrible disease in pigs., 百拇医药
自八十年代中期以来，该病就成为许多国家的恶梦。专家估计，目前美国有75%的猪只感染PRRS，疫苗仅仅部份有效。
PRRS病毒首先攻击猪的免疫系统，使猪的机体易发生其它感染，特别是肺部感染。部份猪只可以发生慢性感染并且成为病毒携带者而不表现出症状。PRRS病毒经由精液、唾液和血液传播，在一起饲养及用卡车运输时呆在一起的猪只最容易发生感染。PRRS以多样化的症状为特征，经常导致幼猪死亡。疾病会使母猪丧失90%的受孕率(自然流产或是生下来的幼猪已经死亡)，20-30%的幸存猪只日后也可能死于呼吸系统疾病如肺炎
PRRS研究员，美国明尼苏达大学兽医学院的斯哥特·迪说认为，这种猪疾病带来的经济灾难正逐渐扩大。PRRS病毒虽然不属于艾滋病病毒家族的一个成员，但也是损坏免疫系统并且导致机体出现一些类似艾滋病的变化。
, http://www.100md.com
北卡罗来纳州立大学兽医学院的PRRS研究员蒙蒂·姆索的研究发现，感染PRRS的猪只在下列方面与人类艾滋病类似：
1、出现免疫系统功能抑制，继发感染主要发生在肺部；
2、PRRS病毒首先在肺泡巨噬细胞内复制，使患猪容易发生机会感染；
3、免疫系统的淋巴细胞出现与艾滋病类似变化，生产许多高水平的生物化学物质。
但某些幼猪可以从PRRS病毒触发的严重肺感染中幸存下来，这是PRRS和艾滋病在发展方面的显著差别。
尽管这样，研究两者的相似性仍是很重要的。姆索希望通过更多地了解PRRS，从而了解更多人类艾滋病的知识，并且可能发现有助于治疗这两种疾病的方法。
美国国家猪肉制品委员会的科技副总裁贝思·劳特纳说，PRRS是一种复杂的疾病，它的一些症状类似艾滋病。迄今为止，没有证据证明该病毒能通过任何途径(包括食物)感染人类，也没有发现猪肉中有病毒的迹象。因此，不应该产生“猪把艾滋病传给了人”的错误结论。
, http://www.100md.com
姆索、迪、劳特纳都指出，PRRS病毒具有可变性，这增加了利用疫苗控制该病毒的困难。需要更多地了解猪的免疫系统在感染PRRS时是如何运作的，如PRRS会否将猪身上某些尚未被发现的、可潜在传播给人类的微生物释放出来。另外，也要警惕由于将过多的注意力集中在PRRS病毒上，而将这种疾病过份单纯化，也许还有许多因素复合作用诱发了PRRS。
PRRS在许多方面它仍然如此神秘，尽管目前研究取得了一些进展，但人们对PRRS在任何方面都不容过于自信，有必要进行更多的研究以正确处理、有效控制PRRS。
AIDS-Like Symptoms Threaten Pigs
You thought cows and sheep had problems. It seems a disease with some similarities to AIDS is sweeping through pig farms.
, http://www.100md.com
Forget about the current media spotlight on Mad Cow and Foot and Mouth diseases for a moment. Our discovery today is about a disease in pigs that in many ways is like AIDS.
This horrendous disease, at one point called “swine mystery disease”, “blue abortion”, and “swine infertility”, and now referred to as “Porcine Reproductive and Respiratory Syndrome”, or PRRS, has infected some pigs in about 75 percent of American pig herds, according to experts. Vaccines have only partially been effective.
, 百拇医药
The disease also has been creating a nightmare for many other nations since at least the mid-1980s.
Pigs Are Dying
The reproductive and respiratory syndrome, which often kills baby pigs, is characterized by a variety of conditions and is causing economic hardship for pig farmers. Affected mothers lose up to 10 percent of their pregnancies. Their babies are spontaneously aborted or are stillborn. As many as 20 percent to 30 percent of survivors may suffer and die from respiratory disease, such as pneumonia.
, 百拇医药
The PRRS virus is said to primarily attack a pig’s immune system, leaving the body open to a host of other infections, particularly in the lungs. Some pigs develop a chronic infection and become carriers but show no symptoms.
Research reveals that the virus is transmitted via semen, saliva and blood. Those pigs herded closely together and transported at close quarters by trucks may be more susceptible to infection.
To date, there is no evidence that the virus can infect humans from any source, including via food. Researchers looking for signs of the virus in pig meat haven’t found any.
, http://www.100md.com
Scott Dee with the University of Minnesota College of Veterinary medicine, a PRRS researcher, says the disease is the “most economically devastating swine disease there is”, and that the “problem is getting bigger”, but he bristles a little when I introduce the term “AIDS” into the conversation.
I do so because the PRRS virus, while not a member of the family of viruses to which HIV belongs, is also said to strike the immune system and then cause some changes in the body that are similar to AIDS.
, http://www.100md.com
No Virus Trace in People or Meat
Beth Lautner, vice president of science and technology at the National Pork Producers Council, says PRRS is a complex disease, acknowledges that some of the symptoms are AIDS-like and notes that no trace of the disease has been found in people or meat. She worries that “some people will jump to the wrong conclusion, that pigs gave AIDS to humans.”
Monte McCaw, a PRRS researcher with North Carolina State University’s College of Veterinary Medicine, believes that while the differences between PRRS and AIDS are obvious to researchers, it is also important to study the similarities.
, 百拇医药
McCaw has so far been low-key about his AIDS-related findings. I had to initially research farm bulletins, obscure scientific reports and speeches he gave in order to piece some of his views together.
“I am stunned you found this,” he said, after I had almost given up trying to contact him for an interview.
Some Similarities to AIDS
McCaw has concluded that the following key conditions in PRRS-infected pigs are similar to what is found in AIDS:
, 百拇医药
Secondary infections, mainly in the lungs, are common due to the immune-suppressive abilities of the PRRS virus.
PRRS reproduces in cells called macrophages, which are front-line cells in the body*s immune system.
PRRS primarily reproduces in cells called alveolar macrophages, which are immune cells in the lung. Damaging these lung immune cells makes the animal susceptible to opportunistic infections.
, 百拇医药
Key white blood cells of the immune system (lymphocytes) go through some of the same changes that occur in AIDS.
Lymphocytes produce higher levels of a variety of biochemical substances, as in AIDS.
McCaw adds, however, that some baby pigs that manage to survive the onslaught of infections in the lungs that the PRRS virus triggers end up thriving.
“This is an obvious difference in the way (AIDS and PRRS) generally develop,” he says.
, http://www.100md.com
But McCaw thinks enough of the similarities between AIDS and PRRS that he indicated in a report that he would like to study novel immune therapies in pigs. He also told me: “We would hopefully learn more about PRRS in pigs and maybe AIDS in humans,” and to possibly “find ways to help treat both diseases.”
A recent finding in Dee*s camp should further encourage McCaw’s foray into the AIDS-like dimension of this disease. “We have just learned that PRRS can be transmitted from one pig to another via the repetitive use of (vaccination) needles,” Dee says.
, http://www.100md.com
Dee also says that PRRS hides out in the lymph nodes. The same is claimed for HIV.
More Research Necessary
McCaw, Dee and Lautner all agree that much more research will be necessary in order to get a proper handle on PRRS, in the hopes of better understanding and controlling it. They point to the manner in which the PRRS virus is capable of changing and the difficulty this creates for vaccine strategies against the virus.
, 百拇医药
Much more will need to be learned about how the pig’s immune system behaves in PRRS. Will PRRS, for example, be capable of unleashing some previously undetected microbe in pigs that could potentially be transmitted to humans?
Or, for that matter, is this pig disease being oversimplified by focusing so much of the attention on the PRRS virus? There may well be a number of factors that initially combine to trigger PRRS. The disease has often been referred to as a “mystery,” and in many ways it remains so.
While progress has been made, no one should be overconfident about any aspect of this terrible disease in pigs., 百拇医药
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