Researchers are hopeful that they may be getting closer to a method for early detection of the Ebola virus, with a study showing preliminary markers of similar diseases in monkeys. In the study, from Boston University School of Medicine, monkeys were infected with either Marburg virus or Lassa virus, which are similar to Ebola. Scientists then attempted to detect early signs of the infections. Results suggest that it may be possible to test for the viruses much earlier.
Current tests for these three viruses, Ebola, Marburg or Lassa, look for evidence of the actual virus in the blood. However, before spreading to the bloodstream the diseases first infect internal organs. It can take up to 21 days for a person infected with the Ebola virus to show symptoms. Treatments have a better chance of being effective during the early stages of the Ebola virus disease, so interest is high in closing in on early detection. In addition, Ebola does not become contagious until symptoms appear, so early detection might help to prevent the disease from spreading.
Rather than looking in the blood for viruses, the researchers in the current study looked for evidence of the body’s immune cells responding to the virus, specifically looking for patterns of gene expression that would indicate whether or not certain genes are “turned on.” They found gene expression signatures distinct enough to distinguish Lassa virus infection from Marburg virus infection, both before the animals showed any signs of disease.
Study researcher and associate professor of microbiology John Connor said that it appears there are some very distinct and early indications that the immune system is responding to different diseases. This could be an important way of finding people who have the infections before they actually show symptoms and become contagious.
Meanwhile, America has been declared to be free of the Ebola virus with the medical clearance of emergency room doctor Craig Spencer, who was diagnosed with the disease on Oct. 23, a few days after returning from treating patients in Guinea. Manhattan’s city Health Department issued a statement on Monday saying that, after rigorous testing, Spencer had been cleared.
Spencer’s diagnosis with the Ebola virus caused widespread concern since he had been out in public doing such activities as riding subways and bowling prior to becoming symptomatic with the disease. The public is constantly reminded that Ebola is not an airborne disease, so simply breathing the same air as an infected person does not transmit the infection. The virus can only be spread to someone having direct contact with blood and body fluids from an infected person, or with objects contaminated recently with those fluids. The Centers for Disease Control and Prevention (CDC) says that even if surfaces are contaminated, the virus is not hardy and does not survive long in such environments.
The study was published in the Nov. 6 journal BMC Genomics. The researchers cautioned that the findings are only preliminary, and further work is needed to determine whether the method can develop into a practical early detection test for the Ebola virus disease for use in humans, although results indicate they may be getting closer. Researchers also need to look specifically for immune cell gene expression signatures that are reacting specifically to the Ebola virus. Connor said there are certain types of diagnoses that are important not to get wrong. A positive diagnosis could have “fairly significant consequences” for a person, such a quarantine and th widespread concern of infection.
By Beth A. Balen