Zika in the Eye?

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As the case count of Zika continues to increase, we are learning about more interesting symptoms and complications of the viral infection. A new study by scientists from Brazil and Stanford University has found interesting new ophthalmologic symptoms of the virus in 3 case studies of babies born with microcephaly whose mothers were infected with Zika in the first trimester of pregnancy.

They found 3 main retina problems – first was hemorrhagic retinopathy (Yay, bleeding! We love bleeding in this class), in which there is bleeding in the retina. The also found abnormal vasculature in the retina, with missing blood vessels where cells may have died. Thirdly, they noticed torpedo maculopathy in children, which is the presence of lesions in the macula.

The more we learn about the disease, the scarier it gets. It will be very interesting to see as new basic biology research starts rolling out what the mechanisms are that are causing these symptoms. In particular, I think things will really heat up as we start learning more about its long term effects, particularly on women and pregnancy, and its effects on adults.



Jamaica closing borders to Yellow Fever

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We have discussed a lot in class the implications of closing borders to travelers with disease, and whether that is a feasible preventive strategy. This is an incredibly relevant question, as news broke that Jamaica is closing its borders to travelers from countries where the Yellow Fever outbreak is raging. Travelers must present a certificate of vaccination before they are let back in. This measure was taken because Jamaica believes that the vector mosquito and endemic areas are too close for them not to take aggressive preventive measures.

However, as we have discussed many times, there are many unwanted repercussions to closing down borders. It creates a panic in endemic countries, and encourage illicit crossing of borders and travel that makes it much harder for epidemiologists and public health professionals to track down and contain infection spread. It also encourages underreporting of symptoms as people are afraid of the government interfering with their lives and causing problems. In this case, it would also beg the question of equity – is the yellow fever vaccine available to everyone traveling? In most cases, there seems to be an under-supply of the vaccine, and it may only be available to people of a higher SES, which is unfair to those who just don’t have access to the vaccine and thus cannot show proof of vaccination in order to be let back into the country. There are a whole host of issues associated with this policy, which has not proven to be useful in the past. We should really encourage governments to be more critical before they put policies like this into play in the future.


Is Alzheimer’s Disease caused by viruses?

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Although this is not viral hemorrhagic fever news, I thought that this new study was too interesting to pass up a chance to discuss. Essentially, researchers at Harvard are hypothesizing that the plaques that form in the brain that are a hallmark feature of Alzheimer’s Disease form because of a viral or bacterial particle that passes the blood brain barrier. It has been noted that the barrier gets “leakier” with age, and certain infectious particles have a higher likelihood of getting in to the brain.

Scientists had previously noted that the structure of the beta amyloid protein was similar to innate immune system proteins, even though the reigning theory about the proteins is that they are garbage that builds up in the brain with age. The lead investigator, Dr. Moir of Harvard Medical School, hypothesized that these proteins in the brain were actually reacting to invading particles, and forming a cage around them to prevent them interacting with the brain. This is also how the immune system deals with threats in other parts of the body. However, the once the particle dies, what is left is the cage of protein, which is essentially the characteristic plaque of AD. The scientists have found supportive evidence for this hypothesis in petri dish neurons, yeast, round worms, fruitflies and mice.

This is a fascinating new turn for Alzheimer’s Disease, and it’s very interesting how this new theory helps explain a lot of interesting findings in the past that we did not know what to do with. Previously, researchers found that patients who developed AD had higher numbers of antibodies to Herpes virus, but found a causative link to be too much of a stretch – this might begin to explain that finding. Honestly, it’s also amazing to me how paradigms for research can change with a single study, which is what is happening right now in this field. It will be really interesting to see the follow up research done in response to this!

Teen discovers anti-mosquito serum

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In today’s episode of high school students showing up experienced researchers, a teenager in the Philippines discovered that a chemical in a plant that grows in his backyard, Codiaeum variegatum, is toxic to the larvae of Aedes Aegypti, the mosquito that is the vector for Zika virus, Dengue virus and Chikungunya. He decided to test 3 plants in his area, distilled the main extract of the plant, and tested its effects by introducing it to water containing mosquito eggs and larvae. He found that all 3 plant extracts were able to interfere with healthy growth, but that Codiaeum variegatum in particular was incredibly toxic. He presented this finding at the Intel Science fair this year.

Although he started with an initial focus on Dengue, his research is now generating a lot of interest because of its applicability to Zika. I think it will be really interesting to see if we can apply this model to science overall in order to generate cool new discoveries. In this case, getting plant extracts and running quick toxicity tests is clearly something that people without much advanced scientific training can do. If we are able to crowdsource experiments like these, we would be able to get so much more data on potential new chemical compounds, that could be funneled into more advanced research based on initial data. Also, it’s a free and abundant source of labor, so that seems like a great idea!

Lassa fever in Liberia

As of May 20, of a suspected 38 cases of Lassa fever, 15 people are dead. The good news is that the WHO has stated the risk of widespread transmission is low, and Liberia has not been placed under any travel advisory. Recommendations have been made for Liberia and other west African nations to step up their surveillance for Lassa. This is easier said than done, as Lassa presents via a number of different symptoms and is difficult to distinguish from ebola and other hemorrhagic fevers as well as malaria. The two diseases are so close that the initial ebola outbreaks in Liberia several years ago were originally diagnosed as Lassa fever. Liberia has an extensive history with the virus, and it is quite prevalent throughout West Africa. Nearly 300,000 people each year are diagnosed with Lassa and up to 5,000 people die from the disease.

Lassa is less severe than ebola, but can be fatal. Of the patients with Lassa who end up hospitalized, between 15-20% die. Pregnant women are considered especially at risk for serious forms of the illness, due to the virus’ affinity for placenta and vascular tissues. Transmission of Lassa occurs via rodent urine and feces. 80% of infected individuals are asymptomatic, but the remaining 20% experience a number of nonspecific symptoms. Fever, facial swelling, fatigue and conjunctivitis are common indicators.

New Hemorrhagic Fever?!?!?!

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Good news, everyone – looks like there’s a new hemorrhagic fever on the horizon! There are, as of May, 51 suspected cases (and 10 deaths) of this fever of unknown etiology in South Sudan. Symptoms include all of the run of the mill hemorrhagic fever symptoms, including unexplained bleeding, fever, fatigue, headache and vomiting. The samples were sent to the WHO for testing, and came up negative for all of the known hemorrhagic fevers.

This development is exciting for those of us who study these diseases, but honestly terrifying for everyone else. Given how viscerally scary and disgusting this particular class of diseases are, it’s definitely scary to have new ones popping up out of the blue. It will be interesting to see how far this one will spread, although luckily it looks like there is no documented human to human transmission. I also wonder what lessons we can learn from the Ebola epidemic to minimize harm for this new fever.

Interestingly, a viral agent has not been confirmed, given how new this outbreak is. Bacterial agents and food intoxication are still being explored as possibilities, and it will be fascinating to watch this investigation unfold over the next few weeks and months.

We learn new things every day! #biology


A relatively new viral hemorrhagic fever syndrome, Severe fever with Thrombocytopenia Syndrome (SFTS), caused by the SFTS virus, is an exciting area of new research. The SFTS virus is a recently-discovered bunyavirus with a high case fatality rate endemic to China, South Korea and Japan. Very little is known about this virus’s mechanisms for binding and entry into human cells, which is what this paper published in the Journal of Virology studied. This study used a pseudotype vesicular stomatitis virus with unmodified glycoproteins of SFTSV to study the virus entry into host cells. They concluded that the use of lysosomotropic agents indicated virus entry occurred through pH-dependent endocytosis, a very common viral entry mechanism. They found that a soluble oxysterol metabolite inhibited the cell entry and membrane fusion of the virus, and encouraged further research on this pathway for development of antiviral agents.
I found this article fascinating, since it highlights how little we know about this virus. We have discussed the epidemiology and policy factors of a lot of the viral hemorrhagic fevers in this class, but it is very interesting to delve deeper into the biological mechanisms of disease and how this sort of research can shed light on our management of disease.

Another hemorrhagic fever, another reason to never leave your home

Great news everyone! Hantavirus is back in town.

Taiwan’s Kaohsiung City Health Department reported a case of hantavirus back in March, but the great news is that it gets better. This particular individual developed hemorrhagic fever with renal syndrome (HFRS). HFRS adds a new layer of excitement to the run-of-the-mill hemorrhagic fever symptoms that anyone can get. The addition of renal complications and fluid loss through over-production of urine complicates and already messy treatment. Fluids are usually administered to hemorrhagic fever patients, but must be especially monitored in those with HFRS, since their kidneys have lost all sense of what to do.

April saw the confirmation of a third case of hantavirus in the same city as the patient in March. It’s probably not worth panicking quite yet, since Taiwan has only had about 19 cases of hantavirus infection since 2001. But the incidence of three separate infections this year has some officials at the CDC monitoring the island nation. Hantavirus also recently popped up in New Mexico and Montana,  but have so far been limited to single digit infections. However, one patient in New Mexico did recently die, but it is unclear if this was due to the virus or his age.

Hantavirus is an exciting variation on the traditional hemorrhagic fever. Instead of bleeding from every orifice in your body, fluid accumulates in the lungs. Shortness of breath following a flu-like illness is a fairly good indicator of a possible hantavirus infection, especially if the patient has had contact with rodents of any kind. Those cute little mice in your back yard carry hantavirus, which becomes aerosolized in their feces. So if having hantavirus wasn’t enough, you now have to live with the fact that you breathed in mouse poop. Gross.

Is Yellow Fever the new Ebola?

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The threat of the next viral epidemic is always looming, and it is often hard to tell where the next attack will come from. In the last couple of months, an outbreak of Yellow Fever in Angola and surrounding countries seems to be spreading unchecked and causing alarm in global health professionals. As of this month, there were 2023 reported cases of Yellow Fever in Angola, and 258 deaths. Cases linked to the Angola outbreak have been reported in Uganda, Kenya, Peru and China, indicating a global spread of the disease linked to travel.

Global health professionals are becoming more alarmed as the numbers increase, and are lamenting the lack of international and WHO response to the epidemic in a way reminiscent of the early stages of the Ebola outbreak in West Africa. Although a vaccine exists for Yellow Fever, there is a severe shortage of supply. Experts are recommending that the WHO convene with vaccine manufacturers to increase production to control the outbreak, or declare a state of emergency usage of vaccines that allows lower dose vaccines to be used if there aren’t enough full doses to go around.

Only time will tell if this Yellow Fever outbreak will rise to the same levels of severity as Ebola, but the similarities are striking. It is even more alarming that this is happening for a disease with a known (and famous) vaccine. Hopefully, we are able to learn from our botched response to Ebola to prevent the same disaster from happening in Angola.

New diagnostic for Zika on the horizon?

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One of the challenging parts of the recent Zika epidemic has been the lack of low cost, reliable testing for the virus. Zika presents with flu-like symptoms, and is hard to differentiate from other illnesses. Luckily, researchers at Harvard have claimed that they created a low-cost paper diagnostic for Zika.

The research group created a 3 step workflow, which includes Zika detection, strain identification, and a gene editing tool to find specific markers. An amplified RNA sample is applied to a paper test strip, which turns a different color in 30 minutes to an hour baed on the result. It is based on synthetic biomolecular sensor technology embedded into paper, which this lab has been working on.

This type of research bodes well for low cost diagnostic testing, which is desperately needed, especially in developing countries. A huge part of epidemic control is being able to identify cases of the disease, which has been particularly troublesome with Zika. Especially as mosquitos spread, and Zika enters new areas (30 states in the US have the mosquito vector that carries Zika!), diagnostics that can be widely used are key. Before we go ahead and use this test, the specificity and sensitivity of the test need to be better understood and reported upon. But if those can be established for this test, we should definitely encourage its wide usage.