科學(xué)家最近已成功把常見的絨猴作為新的供拉沙熱研究的動物模型。拉沙熱在西非流行，該病毒每年可殺死成千上萬的人。

絨猴是一種小型靈長類動物，完全成熟后只有約1磅重，但是在許多遺傳學(xué)和生理學(xué)上與人類非常接近。使用絨猴的一個優(yōu)點就是此動物對拉沙病毒感染后的反應(yīng)完全與人類對該病毒的反應(yīng)類似。
對絨猴的研究可加快對拉沙熱病毒疫苗的研究，包括已研發(fā)的疫苗以待動物模型的檢測，病毒學(xué)和免疫學(xué)專家Jean Patterson解釋道。

目前，在馬里蘭大學(xué)生物技術(shù)中心已研制的拉沙病毒疫苗已在絨猴身上檢測。“擁有這種動物模型比起還未擁有時，測試疫苗有效性的周期將大為縮短。”Ricardo Carrion說，“并且因為這種動物模型比已存的動物模型對拉沙病毒的反應(yīng)更加真實，所以它是一種優(yōu)先的動物模型。”

拉沙熱是一種病毒引起的疾病，主要發(fā)生在西非，通過大鼠傳播，這種嚙齒類動物能在有人類居住的環(huán)境下快速繁殖。僅20%的感染拉沙病毒的人會出現(xiàn)嚴重的癥狀。對那些患病的人來說，死亡率在15-20%，而對孕婦來說，死亡率會升至60%。如同人類，絨猴患病后的20天內(nèi)將會死亡。而對于恢復(fù)的病人來說，30-40%的人會喪失聽力并造成肝臟損傷。

拉沙熱同樣可以導(dǎo)致嚴重的免疫系統(tǒng)抑制，這也是現(xiàn)今對絨猴疫苗研究的一個方向。“孕婦的死亡率如此高是因為其已經(jīng)處于免疫抑制狀態(tài)。” Patterson解釋道。


Lassa Fever: New Animal Model

Scientists have developed the common marmoset monkey as a new animal model for Lassa fever research. Lassa fever is endemic to West Africa, the virus kills thousands of people each year.The marmoset is a small primate that weighs about one pound when fully grown, but it has many genetic and physiological similarities to humans. An advantage of using marmosets is that the animal’s response to Lassa infection completely mimics the response found in people who develop symptoms.
 
The availability of the marmoset for this research is expected to speed the testing of potential vaccines against Lassa fever, including a number of candidate vaccines that already have been developed and are waiting on a model like this for testing, said Jean Patterson n, chairman of the Department of Virology and Immunology at Southwest Foundation for Biomedical Research (SFBR). 

Already, the scientists have been working with marmosets at SFBR to test a promising Lassa fever vaccine developed at the University of Maryland Biotechnology Institute. “Having this model will allow investigators to test their vaccines more quickly than they would be able to without it,” Ricardo Carrion Jr. said. “And because it mimics the human response to Lassa more faithfully than existing models, it might become the preferred model.” 

Lassa fever is a viral illness that occurs in West Africa, spread by the “multimammate rat,” known for frequent breeding and a tendency to colonize where people live. Only about 20 percent of people infected with Lassa develop severe symptoms. Of those who get sick, the mortality rate is from 15-20 percent, but the mortality rate rises to 60 percent for those who are pregnant. Like humans, marmosets that die from the disease do so within 20 days of becoming ill. Of those people who recover, 30-40 percent suffer hearing loss and liver damage. 

Lassa fever also causes a marked suppression of the immune system, an aspect of the disease that the researchers are tracking with the current marmoset vaccine study. “Pregnant women have such a high mortality rate from Lassa because pregnancy already causes immunosuppression, and Lassa compounds it,” Patterson said.