In an interview published in 1999, The Lancet , Scott Halstead said his biggest regret was not winning the Nobel prize, his worst habit cried a lot, and his favorite ways to relax was "skiing, tennis and sex (not necessarily in that order)." it was equally shameless of what he considered his greatest professional accomplishment :. affirming once controversial that antibodies against one type of dengue virus could "improve" subsequent infection by a different strain, leading to a fatal hemorrhagic fever
Halstead, now 86, is one world leaders on viruses spread by mosquitoes, including dengue, Japanese encephalitis and chikungunya. It continues to be a scientific provocateur, and he has interesting ideas about the probable fate of Zika and factors that may have converted from a human virus largely harmless in a major threat to infants.
Halstead began studying viruses transmitted by mosquitoes in 1957, when the US Army drafted him shortly after graduating from medical school. He remained with the army until 1965, running a virology laboratory in Thailand for 5 years. His long career then took him to Yale University, the University of Hawaii, the Rockefeller Foundation (he started the Children's Vaccine Initiative), Johns Hopkins University, and the Office of Naval Research. Since 1999, the base of the house was the Uniformed Services University of the Health Sciences in Bethesda, Maryland.
Science caught up with him on March 3rd for one night a phone call late while in Shanghai, China, in collaboration with a colleague there on dengue project
Q :. Early studies of Zika virus and yellow fever in populations of African apes found that viruses disappear for years, and then return. Last year you published an article on chikungunya which showed a similar act disappearance in human populations
A :. This virus was shown all over the world for centuries and every time it seems that everyone thinks it is a new event. When chik [ungunya] showed in Reunion [in 05], they thought it was the first time chik [ungunya] had never been that far from Africa. He did this every 50 years as long as the Europeans have sailed the Indian Ocean, and who knows what happened before. These things simply forgotten.
The Sultan of Zanzibar doctor makes these descriptions chik [ungunya] in 1870 and it looked like the virus appeared on the island of Zanzibar and then he crossed the Indian Ocean and created an epidemic across India. In his conversations with the elderly living in Zanzibar, he realized that the epidemic of 1823 had actually been around the Cape of Good Hope and went in the Caribbean.
People wonder how chikungunya escapes from East Africa and travel through the Indian Ocean, but the biggest mystery is why there is this periodicity of 50 years in Africa
Q: Do you think Zika have traveled around the same centuries ago unnoticed
a: No obvious. These Trans-Indian Ocean epidemics all seem to be chikungunya because of the deep arthritis that accompanies the disease. The latter Zika biological manifestation of passing the placenta and affect the fetus is absolutely new. If something like this happened in epidemic proportions, believe me, human beings have noted down
Q:.? What is the similarity between Zika, chikungunya and yellow fever that could explain this periodicity
A: The nature of these zoonotic diseases is that they involve primates. If you dug into it that you likely find it has something to do with time and fruiting trees and ape populations become really big and then you have the enormous animal diseases. There is no doubt that the herd immunity in humans must be very important, too, and the size of the population
Q :. Can you give an example
A: When I lived in Thailand in early 1960, we have intensively studied chikungunya and he was absolutely everywhere. By 1975, chikungunya had absolutely disappeared in Thailand.
Chikungunya had become endemic because Aedes aegypti population was extremely high and the human population was high. When I was in Thailand, the average household size was six. In the 1970s, family planning was introduced and within a generation the population of Thailand was reduced to two children per family today. Once you eliminate all those extra children in a family, you eliminate a huge percentage of the susceptible population that keeps the virus will.
We can actually measure the immunity of the herd and see when epidemics stop. The herd immunity [threshold] dengue for example, is about 80%. Chikungunya and Zika are probably the same, which means that when 80% of the population at risk is immune, the transmission is blocked four times out of five and one out of five is simply not enough to keep the current disease.
Q: Chikungunya first surface in the Caribbean in modern times in 2013. How long do you think that it will stay around
A: Five years, max. The only model I have is India. I was watching when chikungunya went from Africa to India in 1963 and disappeared from India in about 5 years
Q:.? Zika
A: Zika is the same
Q :. There is a great rush to make vaccines against Chikungunya and Zika because there is fear. But for Brazil, for example, when there is a vaccine, you suggest the country's population could be largely immune to Zika
A :. Exactly. It is like Ebola. It will be gone. We'll have that Ebola vaccine, which is about 85% done, and it will stay there until the next outbreak.
There are lots of people running around saying that he will be Zika and chikungunya in these new places forever. I do not think so. Based on the observations that I made and that everyone can see with their own eyes they look at the data, this virus is just going to get burned. There is only a need for a vaccine in the acute emergency
Q :. Do you think a enhancementlike antibody functionality with Zika is behind the serious illness that has been linked to microcephaly in babies and adults Guillain-Barré syndrome?
A: Absolutely. I am certain. I would bet a lot of money.
In the 1980s Ademola Fagbami Nigeria came to my laboratory at the University of Hawaii with Zika virus and we have experience, we published, which showed that it can be improved in mononuclear phagocytes [a type of immune cell]. We know that it thrives in these cells and the antibody can be improved. Zika is in fact genetically close enough to the dengue virus, which means a large number of zika on surface proteins are identical to the surface proteins of dengue. It absolutely would not surprise me to find that the antibodies of dengue infections and improve Zika that all this scanning Zika across the Pacific and South America have all been promoted and propelled by the development
Q :. What are the major unknowns about Zika
A: she -t grow in primary human monocytes in vitro? If someone dies can we find the virus in monocytes and macrophages in vivo? These are the key elements
Q:.? What could be the mechanism behind Zika harm fetus
A: I think the dengue antibody complexing with Zika virus and the immune complex is infected monocytes so you have a much higher amount of virus produced. Perhaps a certain concentration of virus, you start getting the virus spread in the placenta
Q :. When you suggested that antibodies against four different strains of dengue virus could improve was not immediately celebrated for the idea
A :. Let me tell you something, there's no fun to discover something that nobody wants to hear. I always thought to myself, I really discovered something very important, but in reality it is a bit horrible People make antibodies and kill. Nobody wanted to believe improvement dependent antibodies. The only problem is that it is true.
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