Natural Immunity to Ebola- Olivia Cvitanic

A recent study conducted in rural Gabon has concluded that there may be some natural immunity people have acquired to combat Zaire ebolavirus (ZEBOV) in areas where the disease is especially prevalent. The researchers tested 4,349 people from 220 randomly selected villages in Gabon using the ELISA method. Out of the people tested, 15.3 % tested positive for ZEBOV. This figure increased to almost 20% in especially forested areas. Individuals were tested using the Western blot which determined whether an individual had anti-ZEBOV IgG. IgG is an immunoglobin. Immunoglobins are proteins that make up antibodies. Also, researchers studied individuals’ CD8 T cells and tested for an antibody response upon “ZEBOV stimulation.” The results indicate that a significant portion of the population living in very rural areas of Gabon “have both humoral and cellular immunity to ZEBOV.” One theory as to why people in these rural areas exhibit higher levels of immunity suggests that many of the tropical fruits growing in rural Gabon have been contaminated by bat saliva. Fruit bats have been known to spread the disease so this theory is possible. While Ebola is not a serious problem in the United States, there are serious outbreaks that occur in Africa. In order to prevent future outbreaks or even eradicate the disease completely in Africa, is it possible to use these ZEBOV immune people’s blood serum in the same way it was done with Lassa virus? In The Coming Plague, a missionary nurse, Ms. Pinneo, survived Lassa fever and anti- Lassa antibodies were present in her blood afterwards, though she suffered debilitating effects from the disease later on. Since, in the case of Ebola, there are only two strains Ebola-Zaire and Ebola-Sudan, I don’t see why a vaccine could not be developed to prevent future outbreaks or at least “a serum” to help treat infected persons as was used to treat a researcher infected with Lassa fever in The Coming Plague. To be honest, this article was a little difficult for me to understand because of all the medical and biological jargon; however, the presence of Ebola immunity was news to me and I thought deserved attention. Many of the terms such as seroprevalence and IgG I had to look up on my own. If you would like to read more, here’s the link:http://www.flutrackers.com/forum/showthread.php?t=140894

The needle and the damage done

The retraction of the Wakefield article has provoked a number of editorial and Op-Ed pieces. I spotted this one in the LA Times a few days ago - The damage of the anti-vaccination movement.

Some groups claim only to oppose mandatory vaccines, but this ignores the need for what's called "herd immunity." That means a certain level of the population must be vaccinated (generally around 85% to 90%) so those unvaccinated are still protected.

Lack of herd immunity is what killed Gabriella "Brie" Romaguera. The New Orleans baby died of pertussis, or whooping cough. At one time, this disease afflicted more than 250,000 American children yearly, killing 9,000. Vaccinations reduced that to just 1,000 new cases annually by 1976; but by 2008, cases had soared to more than 10,000 annually.

Brie contracted the disease when she was a month old, too young for her first pertussis vaccine. "I'm not laying blame," her mother, Danielle, told me. "But people need to know they can infect other people's babies. It kills. People think these diseases don't exist anymore, but that's only because children are being vaccinated."

Disease on the radio

A story from NPR's On the Media covering the recently retracted paper falsely linking autism and the MMR vaccine.

From the same program, a story about whether or not the World Health Organization dropped the ball on the H1N1 outbreak. Very relevant to the course, including a discussion on how to define a "pandemic".

Hot off the press

A broad-spectrum antiviral targeting entry of enveloped viruses in Proceedings of the National Academy of Sciences this week.

We describe an antiviral small molecule, LJ001, effective against numerous enveloped viruses including Influenza A, filoviruses, poxviruses, arenaviruses, bunyaviruses, paramyxoviruses, flaviviruses, and HIV-1. In sharp contrast, the compound had no effect on the infection of nonenveloped viruses. In vitro and in vivo assays showed no overt toxicity. LJ001 specifically intercalated into viral membranes, irreversibly inactivated virions while leaving functionally intact envelope proteins, and inhibited viral entry at a step after virus binding but before virus–cell fusion. LJ001 pretreatment also prevented virus-induced mortality from Ebola and Rift Valley fever viruses.

Although the compound does cause damage to host cell membranes whose composition is nearly identical with that of virus envelopes, it caused them no ill effects. The reason, according to the researchers: Cells can rapidly repair their membranes, but viruses can't fix their envelopes.

"At antiviral concentrations, any damage it does to the cell's membrane can be repaired, while damage done to static viral envelopes, which have no inherent regenerative capacity, is permanent and irreversible."

A more general description of the paper is available here but there hasn't been much media interest in this exciting development yet.

Hans Rosling on AIDS

Hans Rosling unveils new data visuals that untangle the complex risk factors of one of the world's deadliest (and most misunderstood) diseases: HIV. He argues that preventing transmissions -- not drug treatments -- is the key to ending the epidemic.

If you think this is a pretty cool presentation (which it is) then check out his most famous presentation 'the best stats you've ever seen' where he debunks a number of myths about 'developing' countries.

Sunday is National Black HIV/AIDS Awareness Day

National Black HIV/AIDS Awareness Day, February 7th of every year, is a national HIV testing and treatment community mobilization initiative.

Among all race/ethnic groups, HIV prevalence is highest among the Black community, who account for 46% of the population living with HIV despite comprising just 12% of the population.

Phillip Cohen at the Huffington Post has more shocking statistics.

Acquaintance Immunization

Image from inSPOT a nonprofit Internet notification service that allows you to send e-cards to your sex partners to break the bad news that they should get tested. Cards can be sent anonymously but they suggest, not unreasonably, that cards with a name are much more effective.

On a related note tell me that this isn't a good idea:

It is well established that random immunization requires immunizing a very large fraction of a computer network, or population, in order to arrest epidemics that spread upon contact between infected nodes (or individuals. Many diseases require 80%– - 100% immunization (for example, measles requires 95% of the population to be immunized). The same is correct for the Internet, where stopping computer viruses requires almost 100% immunization. On the other hand, targeted immunization of the most highly connected individuals, while effective, requires global information about the network in question, rendering it impractical in many cases. Here, we develop a mathematical model and propose an effective strategy, based on the immunization of a small fraction of random acquaintances of randomly selected nodes. In this way, the most highly connected nodes are immunized, and the process prevents epidemics with a small finite immunization threshold and without requiring speci fic knowledge of the network.

From a paper entitled 'Efficient Immunization Strategies for Computer Networks and Populations' in Physical Review Letters.

So, for example, for a sexually transmitted disease you would only need the identity of a single sexual partner from a large sample of people (unfortunately this should be a random selection from those available which may cause difficulties). You then collate this information and target your vaccination on those names that come up the most frequently (most likely the 'superspreaders' in this case). But you have identified them without constructing the whole partner network.