Author Archives: ycpmicro
Ashley Hiltebeitel (12 Micro) finds Ebola virus fascinating, and noted in the comment thread to the previous post that she is working on a research paper for her Academic Writing class on the topic! It is unclear exactly how big the outbreak is, and epidemiologists are using many approaches to define the size of it. Ashley presents one approach for finding out how significant the outbreak is in non-human primates, from a news alert on Science Daily summarizing a primary research article in the journal PLoS Neglected Tropical Diseases. Here is Ashley’s summary:
The Wildlife Conservation Society (WCS) has led a research that uses fecal samples from wild great apes to center in on the populations that have been infected with the Ebola virus. This discovery will change the way the Ebola virus is studied. Because it is hard to capture and sample the wildlife in West Africa, it makes it hard to figure out how it emerges and is maintained in wildlife. Using the feces from the great apes gives scientists a cheaper, more simple and non-invasive technique to acquiring information about the disease. This new methodology also gives scientists the fact that apes develop antibodies against a disease to survive just as humans do. They also developed a way to isolate the antibodies from the ape’s feces. 10% of samples from 80 free-ranging wild gorillas from five different habitats tested positive in showing the Ebola virus in their feces.
The worst ever human epidemic of the Ebola virus is ongoing right now throughout West Africa in Guinea, Liberia, Nigeria, and the Sierra Leone. The zaire species of the Ebola virus is the one responsible. This species has been the cause of major human outbreaks before as well as major declines in the chimpanzee and gorillas populations all over central Africa. The human outbreaks have followed the wildlife outbreaks in the past. They transfer to humans from eating infected wildlife. including apes and fruit bats. Therefore, this spillover from wildlife to humans could easily be avoided by not consuming dead wildlife or buying the bats that are sold as food in markets. Because there is no cure for this disease yet, barrier nursing, supportive care, contact tracing, isolation of those who become ill, and education of the public is the only way to try and stop the spread of the disease from human to human. This is much harder to do in less developed nations than the United States where the Ebola virus has emerged repeatedly.
Alain Ondzie, a WCS veterinarian, made a great point by saying, “If scientists can better understand patterns of Ebola virus infection in wildlife, the public health sector can be more prepared to prevent human outbreaks.” The presence of the virus in the ape’s feces shows that some apes survive the Ebola virus. It also shows the regions where the Ebola virus has emerged and which populations of apes are more prone to getting it. Further investigation will need to be done to to see if antibodies persist or whether they pose protection against future infection of the disease.
The benefits of collecting ape feces include being able to cover large areas of forest more quickly without the expense of capturing and handling the animals. It also opens interest to better understand the ecology of the disease and some management options. This could include the study of immune response that could be compared with the genetic information of individuals after an outbreak. Scientists could use this technique with other species that play roles in the transmission of the Ebola virus as well, including wild pigs and antelope.
The Centers for Disease Control and Prevention have taken the unusual step of revamping their main website in response to the significant outbreak of Ebola Hemorrhagic Fever in central Africa. Traditionally, outbreaks of this disease have had epidemiologists worried when they occur, but fortunately the severity of the disease also means that it outbreaks have been contained rapidly, and the number of deaths historically have not been high with at most a few hundred deaths. The mortality in all outbreaks however has been high, with up to a 90% fatality rate in a 2003 outbreak in the Dem. Republic of the Congo. Currently, no treatment or preventative vaccine exists for Ebola virus.
The current outbreak is historic in its severity; as of late September, an outbreak in West Africa has affected over 6000 people with about a 50% death rate. The origin of this and previous outbreaks is similar, with the virus moving from its native reservoir in bats to non-human primates, and then to humans. Outbreaks in human populations then occur when human to human transmission occurs with high frequency. The CDC estimates that this number of cases will continue to rise, with potentially 21,000 cases by the end of September, and estimates from the World Health Organization are similar in scope.
To curtail this rise in cases, immediate measures need to be instituted, primarily consisting of ensuring that sick individuals are cared for in equipped Ebola Treatment Units, or if full, in home/community settings with appropriate infection control procedures in place including safe burial procedures. The CDC currently has over 700 staff members actively working on the epidemic at labs in the US, and have deployed almost 100 specialists to offer assistance in the affected region. Part of their work oversees is to assist with screening measures to prevent the epidemic from spreading to other regions, and ensuring that medical and humanitarian resources can reach the affected areas. For US citizens, a non-essential travel alert for this region has been issued.
Public health investigators think that the current outbreak is so severe for a variety of reasons. Seasonal climate variation has potentially created an environment where the virus flourishes in its animal reservoir, or perhaps facilitates transfer from the bat to other transient animal carriers. Development into the jungle has eased the movement of people into regions where the virus is natively found, making animal-human transmission easier. Additionally, political turmoil makes it more difficult for health officials to rapidly respond when an outbreak occurs, and the current outbreak region spreads over several political jurisdictions. Together, these factors have combined for a perfect storm enabling a much greater outbreak than previously seen. The good news in all of this is that there is an international response to the outbreak, and the likelihood of the epidemic spreading to the United States remains very small, even when patients are brought to the US for treatment.
Rebecca Donovan (11 AM Micro) is interested in the normal microbiota. I have had a long-standing interest in the role of the gut microbes, and how recent studies have implicated them in a variety of phenomena–see for instance this report about how gut bacteria play a role in mate selection, or this one about a dating service based on gut bacteria. Rebecca’s summary shows that what we feed those bacteria is as important as the types of microbes themselves. Here’s Rebecca’s story, and for those who read to the end, a BONUS opportunity:
A recent article, published on sciencedaily.com, discovered that artificial sweeteners may be doing more harm than good in your body. Originally marketed to be the ideal solution to those desiring a lower calorie, “sugar less” way to avoid diabetes, recent research has suggested that artificial sweeteners are actually promoting glucose intolerance in the body. If, by this point, I have not convinced you to put down that diet coke in your hand, please read on.
How does this happen?
According to Dr. Eran Elinav and Professor Eran Segal, both of the Weizmann Institute of Science, our gut microbiota, or the bacteria residing in our intestines, are the likely culprits. To confirm this idea, the scientists gave mice water that contained three of the most readily used artificial sweeteners, saccharin, sucralose (splenda), and aspartame (Equal). They found that giving these mice the artificial sugar water promoted development of glucose intolerance to a much greater extent compared to mice only given plain water (Weizmann Institute of Science, 2014). It is also worth noting that mice who were given water containing real sugar developed less of an intolerance to glucose compared to mice given artificial sweetener water. Next, the scientists “cleaned out” the microbiota in the mice through the use of antibiotics. This “clean sweep” of gut bacteria resulted in a return of tolerance to glucose in mice given artificial sweetener water, solidifying the claim of the researchers that gut bacteria are the “prime suspects” in glucose intolerance brought on by artificial sweeteners.
How do these findings pertain to humans? (After all, we’re not mice!!!)
The scientists involved in this experiment “covered their bases” by gathering a group of human volunteers, who rarely consumed artificially sweetened products, to add them to their diets for a week. After this time, their blood glucose levels would be measured. Their gut microbiota would also be analyzed and measured. The results of this experiment were that most of the participants exhibited an intolerance to glucose after ONLY ONE WEEK of consuming artificial sweeteners. Further analysis of the gut bacteria of participants illustrated that, with consideration to those whose intolerance levels towards glucose were not adversely affected, that there are two types of gut bacteria living within humans: a type that reacts negatively to glucose resulting in intolerance and a type that has no effect on glucose tolerance (Weizmann Institute of Science, 2014). The researchers involved in the experiment believe that the aforementioned “bad” gut bacteria “turned on” an inflammatory process in the body, negatively affecting the ability of the body to effectively process sugar.
What should this study teach us?
The ultimate question we should ask ourselves is: why would we want to put substances in our body that are proven to be harmful to us? Diabetes and obesity are still, and will continue to be on the rise, in America if we continue to do little to prevent these diseases from occurring. You can take the first step in preventing diabetes and obesity by eliminating “diet” from your diet. Artificial sweeteners aren’t worth the risks associated with them.
BONUS added by Singleton: in the comment thread, give an example of an association that the normal microbiota has with ANY aspect of human health (good or bad). No repeats, so read what others have put in, and you must give a citation (URL). Don’t worry about formatting of names–I will fix–but do spell them correctly. Offer ends on the end of the day on Friday September 26th.
Maria Allera (11 AM Micro) is worried about parasitic diseases, and with good reason. She found a news alert about the brain eating amoeba, which has long been one of my favorites. Who can forget this classic episode of House which featured Nagleria, and was one of the last times I got to trot out the #BOGUS hashtag? Let’s see if Maria can make us feel better about Nagleria:
Naegleria fowleri is an amoeba that takes residence in warm, fresh water all over the world. Just two weeks ago N. fowleri turned up in a water supply in Louisiana, causing the town to go into a state of emergency to provide bottled water for all the residents. N. fowleri can be found in any body of water, such as lakes, ponds, rivers and even manmade structures like pools or waterparks. The amoeba thrives in hot water and can also be found in water discharges from industrial plants.
When N. fowleri comes in contact with a human it makes its way into the body through the nasal passage, swims to the brain and causes an often fatal infection called Primary Amebic Meningoencephalistis (PAM). Some symptoms of PAM include headaches, fever, nausea, vomiting, hallucinations and coma; all of these can lead to death. Since the 1960’s only 200 conditions have been reported, unfortunately less than 5% survive. The infection can be diagnosed when examining spinal fluid under a microscope to identify the amoeba. Under the microscope the amoeba appears as:
Naegleria fowler is elongated, 15-30 μm, and feeds on Gram-negative bacteria. The cytoplasm is granular, has a single nucleus with a prominent and contains vacuoles. Blunt lobular pseudopodia are formed at the widest point. The flagellated form is smaller, with a pear shape and two flagellae at the broad end. N. fowleri cysts are round, 7-15 μm in diameter and have a thick smooth double wall. N. fowleri is thermophilic, preferring water temperatures between 35 and 46ºC (link here)
Within the amoebas life there are three stages. The first two stages, the cyst and flagellate stage, require low food supply and low temperature. When an amoeba is in the cyst or flagellate stage it cannot survive in human tissue. The human body is the perfect living condition for the trophozoite stage. The amoeba feeds off of the human blood cells, it reproduces by binary fission and destroys other tissues. As dangerous as this microorganism sounds, it all depends how it is ingested to determine if it will cause harm or not. If you consume water with N. fowleri in it, it will process through your digestive system without any health problems. This amoeba is only dangerous when it gains nasal access.
Just like any pathogenic disease everyone wants to know how to prevent acquiring it and how to treat it if acquired. To prevent contracting N. fowleri, it is smart to not submerge your head in fresh water, especially if it is a warm temperature. Try to always swim in treated waters and don’t wash your nose out with fresh water. Do not use a neti pot to clean your sinuses, the water goes straight up the nose so if the water is effected you’re putting your body directly at risk. Unfortunately most infections of N. fowleri end in death, there are a few survival stories. There have been four survival cases in North America, a laboratory did testing and the CDC released
It has been suggested that the original U.S. survivor’s strain of Naegleria fowleri was less virulent, which contributed to the patient’s recovery. In laboratory experiments, the original U.S. survivor’s strain did not cause damage to cells as rapidly as other strains, suggesting that it is less virulent than strains recovered from other fatal infections.
Amphotericin B was the most common medicine to treat amoebas. It’s inserted directly into the brain; however, this treatment usually fails. The CDC also has an investigational drug on study called Miltefosine for three free living amoebas including N. fowleri and it has had much better results.
Abby Nicodemus (11 AM Micro) found a news story via Scientific American, describing recent research published in the journal Proc. National Academy Sciences. The compounds described are being assessed for their antimicrobial properties. Because they are general inhibitors of microbial growth which operate by creating an environment unfavorable for growth, it is possible that this approach will not lead to antimicrobial resistance the way so many other compounds do. Here is Abby’s summary:
The focus of health care is to “[maintain] health by the treatment and prevention of disease especially by trained professionals”, so any scientific advance in the field of bacteria and disease has the opportunity to contribute to the health care field. While scanning through the current topics of microbiology, I stumbled upon an article titled “Liquid Salts Bypass Skin to Treat Infections” and it sparked my interest. Diseases and treatment of diseases being what we are studying in lecture, I thought it would make sense to discuss it in my bonus summary.
The first paragraph of this article discusses biofilms, “packed communities of microbial cells that grow on both living and inert surfaces” (Liquid Salts), which reminded me of the samples we took for the third lab. The significance of biofilms is the part they play in human infections, they are responsible for 4/5 of human infections. A large majority of microbiology focuses on human diseases and treatment. The source of infections and diseases is incredibly relevant in understanding and making scientific discoveries. Knowing more about these infections can help to lower hospital visits. It is known that biofilm infections are responsible for “almost one out of every ten visits” (Liquid Salts).
Specifically regarding biofilms, the structure of these bacterium increase their ability to fight off any treatment, including antibiotics. Skin, our protective barrier, does a more than okay job of keeping things outside of the body, making skin treatment options limited. However, innovations in science have made new categories of treatment a reality. This discovery involving salt absorption through skin widens the possibilities of fighting off infection.
Many of the ionic formulations brought forth by Mitragotri and his team showed effectiveness against treating many bacterial microfilm infections. This study has helped to tie a number of loose ends because “individual parts…have been demonstrated before, but this study draws them together in a very coherent strategy”. Ideas have been proposed involving this method, but only recently have discoveries given those ideas significance and the reality to help the millions of people affected by these diseases.
This technique decreases the amount of bacteria in the body by almost completely eliminating biofilms and minimizing the release of toxins into the human body. Currently, only specific ionic salts have been discovered and engineered to fight infection, but more research can lead to a broader spectrum of treatments for a wider range of infections. Certain salts and ions will penetrate the skin and target certain biofilms more efficiently than others.
Advances are being made in the medical field every day, but this particular discovery has the potential to change the world of disease and help many more people who suffer from bacterial infections and diseases. By eliminating biofilm infections, we can reduce the amount of money spent on treatments and the number of people admitted to hospitals for these kinds of infections will also go down.
In what will undoubtedly be ammo for the antivaxxer movement, the latest issue of Morbidity Mortality Weekly Report from the CDC reports the ongoing surveillance of vaccine administration for seasonal influenza is not perfect. The seasonal influenza vaccine comes in two forms: an inactivated virus formulation that is injected, and a live, attenuated virus formulation that is administered nasally. Both forms of the vaccines are generally widely available in late summer/early fall, and are recommended for the general population of the US for everyone over the age of 6 months. The inactivated vaccine has an expiration date of June of the following year, and is contraindicated for use at that time, mainly because of the lack of protection that it will offer to novel influenza strains that will have arisen by that point. The live attenuated vaccine on the other hand has an expiration date of about 18 weeks (4.5 months), and should be disposed of at that point even if the flu season is still going on. Since the flu season generally runs from November through March, it generally should not expire during this time, however if the vaccine is produced but not administered earlier in the season, stockpiles of expired vaccine may accumulate.
Epidemiologists from the CDC analyzed data from the national Vaccine Adverse Event Reporting System (VAERS), from 2007 through 2014. Of reports using live virus vaccines, approximately 18% of those reports indicated that expired vaccine had been administered to patients, and the vast majority of those reports did not document any adverse health events. The most likely outcome due to administration of any expired vaccine is a lack of protection against season flu. Consequently, revaccination with a valid dose is recommended to maintain protection against flu. The CDC recommends that all health care providers be aware of the significantly shorter shelf life of the live vaccine, and to be aware of return and replacement options from vaccine manufacturers.