- Author: Kathy Keatley Garvey
That's what UC Davis chemical ecologist Walter Leal, co-chair of the International Congress of Entomology (ICE 2016) recently held in Orlando, Fla., wrote in his newly published opinion piece, titled "Zika Mosquito Vectors: the Jury Is Still Out" in F1000 Research.
Leal, a mosquito researcher and distinguished professor in the UC Davis Department of Molecular and Cellular Biology, co-chaired ICE 2016 with Alvin Simmons, research entomologist with the United States Department of Agriculture's Agricultural Research Service (USDA/ARS), U.S. Vegetable Laboratory in Charleston, S.C.
The conference, themed "Entomology Without Borders," drew 6,682 delegates from 102 countries. The last time ICE met in the United States was four decades ago. The venue then: Washington, D.C.
One of the symposia at the Orlando meeting was the Zika Symposium, "which covered multiple aspects of the Zika epidemic, including epidemiology, sexual transmission, genetic tools for reducing transmission, and particularly vector competence," Leal wrote. "While there was a consensus among participants that the yellow fever mosquito, Aedes aegypti, is a vector of the Zika virus, there is growing evidence indicating that the range of mosquito vectors might be wider than anticipated. In particular, three independent groups from Canada, China, and Brazil presented and discussed laboratory and field data strongly suggesting that the southern house mosquito, Culex quinquefasciatus, also known as the common mosquito, is highly likely to be a vector in certain environments."
Leal based his opinion piece mainly on the current literature and the Zika Symposium at ICE 2016, which was organized by Constância Ayres, Oswaldo Cruz Foundation (FIOCRUZ-PE), Recife, Brazil (he collaborates with Ayres) and Adriana Costero, National Institutes of Health, Bethesda, Md. The speakers included worldwide experts from the United States, Brazil, China and Canada.
Ironically, the Zika virus wasn't a household word or in most entomologists' vocabulary when Leal and Simmons began planning the ICE 2016 meeting several years ago.
Now scores of researchers are tackling the Zika virus (ZIKV), first isolated first from a febrile monkey and later from the mosquito Aedes africanus. "ZIKV was isolated from humans for the first time in 1954 during an outbreak of jaundice suspected of being yellow fever," Leal recounted.
"During the discussion at the end of the symposium, the forum was opened for questions and comments," Leal wrote. Scott Ritchie of James Cook University, Australia, asked “Is anyone looking for the virus in birds?”
"This question captures the sentiment that both questions were thought provoking, and we still do not have all or many answers when it comes to ZIKV. Hopefully, we will be better prepared when convening in Finland for ICE 2020. Wouldn't it be wonderful to report in Helsinki that mosquito vector populations have been reduced or eliminated, the Zika and other epidemics were contained, vaccines have been made available, and entomologists are ready to further improve the human condition by tackling other problems than the Zika epidemic?"
Read the entire F1000 piece at https://f1000research.com/articles/5-2546/v1 and ESA's Entomology Today write-up.
- Author: Kathy Keatley Garvey
In a groundbreaking discovery, a scientific team of Brazilians and Brazilian-born chemical ecologist Walter Leal of the University of California, Davis, has announced that the Zika virus has been detected in wild-caught Culex quinquefasciatus mosquitoes in Recife, the epicenter of the Zika epidemic.
Scientists from the Fiocruz Institute, Pernambuco, confirmed the discovery July 21. The detection could have widespread repercussions, as the Culex mosquitoes are more common and widespread than the yellow fever mosquito, Aedes aegypti, known as the primary carrier of the Zika virus.
Leal, who collaborates with Fiocruz Institute researcher Constancia Ayres in a National Institutes of Health-sponsored project on the investigation of Zika in the C. quinquefasciatus, said that the Brazilian lab earlier discovered that Culex had the capability of transmitting the virus. Although the scientists were able to infect the lab mosquitoes with the virus, they had not found the virus in wild-caught mosquitoes—until now.
“This could have major repercussions here in the United States and in other parts of the world,” said Leal, a distinguished professor in the UC Davis Department of Molecular and Cellular Biology who is co-chairing the International Congress of Entomology meeting Sept. 25-30 in Orlando, Fla. The conference is expected to draw some 7000 entomologists throughout the world.
Leal said more work needs to be done to see if Culex mosquitoes are playing a role in the current epidemic. In an interview July 21 with health reporter Jennifer Yang of the Toronto Star, Canada's largest daily, he commented: “It looks like there were more vectors than we thought, and this is one of them. We don't have to panic, but we have to know. And now that we know, we have to take care of the Culex.”
A. aegypti is already established in California; it has spread to at least seven counties since its discovery in Clovis, Fresno County, in June 2013, according to medical entomologist Anthony Cornel of the UC Davis Department of Entomology and Nematology and the UC Kearney Agricultural Research and Extension Center, Parlier.
The Zika virus, which can result in birth defects in pregnancy, can be transmitted through exposure to infected blood or sexual contact. The Centers for Disease Control estimates that between 400,000 and 1.3 million cases have been discovered across South, Central, and North America, where the disease was previously unknown.
Leal and a group of 18 students just hosted a Zika Public Awareness Symposium on May 26 at Giedt Hall, UC Davis campus. The podcast can be accessed at https://video.ucdavis.edu/media/Zika+Virus+Public+Awareness+Symposium/0_n3aupf5c
- Author: Kathy Keatley Garvey
So screamed a recent USA Today headline in a quote attributed to the Centers for Disease Control and Prevention (CDC).
"Public health officials used their strongest language to date in warning about a Zika outbreak in the United States, as the Obama administration lobbied Congress for $1.9 billion to combat the mosquito-borne virus," the publication reported.
And now interest is spiking in the two-hour UC Davis "Zika Public Awareness Symposium," set Thursday, May 26 from 6:30 to 8:30 p.m. in Room 1001 of Giedt Hall and organized by coordinator Walter Leal, a chemical ecologist and professor in the UC Davis Department of Molecular and Cellular Biology, and 18 biochemistry students.
It's free and open to the public: to reserve space, RSVP to ucdstudentsagainstzikav@gmail.com.
The scientific-based symposium will include "expert panels and speakers throughout the United States and the world, including those working on the front lines of the Zika epidemic," Leal said.
Two Brazilian scientists who deal with patients and mosquito vectors at the epicenter of the Zika epidemic will speak (remote). Speakers also will include a scientist involved in the first documented case of sexual transmission of an insect-borne disease; specialists in dermatology, obstetrics and gynecology; and medical entomologists.
The Zika Epidemic – An Overview
Professor Walter S. Leal
UC Davis Department of Molecular and Cellular Biology
Congenital Zika Syndrome
Dr. Regina Coeli Ramos, University of Pernambuco, Brazil (remote)
Zika Virus and Me
Professor Brian Foy
Department of Microbiology, Immunology, and Pathology, Colorado State University
Zika Virus: Looking into Mosquitoes' Vectorial Capacity
Professor Constância F. J. Ayres
Department of Entomology, Fundação Oswaldo Cruz-Pernambuco, Brazil (remote)
Don't Let Mosquitoes Bug You with Zika – Repel Them
Professor Walter S. Leal
UC Davis Department of Molecular and Cellular Biology
DEET vs. Zika – I Would Go with the Former
Dr. Emanual Maverakis
Department of Dermatology, UC Davis School of Medicine
Keeping Mosquito at Bay, Not in Your Backyard
Dr. Paula Macedo
Laboratory Director, Sacramento-Yolo Mosquito & Vector Control District
Friends Don't Let Friends Get Zika
Dr. Stuart H. Cohen
Chief of the Division of Infectious Diseases and director of Hospital Epidemiology and Infection Control, UC Davis Medical School.
At the symposium, attendees will "learn the symptoms and learn the facts and science about Zika and how you can protect yourself from this disease," said Leal, who collaborates with researchers in his native Brazil. He recently participated in the international Zika research symposium there.
"It is very important that students and the public-at-large learn how to prevent a possible Zika epidemic as this is the first virus known to be transmitted both sexually and by mosquitoes," Leal said. "We thought that we did not have the vector (the yellow mosquito), but now our research in collaboration with Brazilian scientists indicates that our local mosquitoes (Culex) are also competent vectors. And more and more we hear cases of travelers returning home infect with Zika virus. I am so glad that a group of 18 students who took my biochemistry class last quarter decided to launch this initiative to educate their peers and citizens of Davis about this dangerous virus."
"This symposium is important to host because Zika is a rapidly spreading across the globe so people need to be informed," said Amarita Singh, one of the 18 students organizing the symposium. "Recent studies have shown that this particular virus not only affects pregnant women, but is a threat to all. Since there is no vaccine or medication, it is better to educate now to help prevention."
"I became more aware of the disease when Professor Leal began to discuss it in our biochemistry class, which is what originally sparked my interest," Singh said. "After learning about how dangerous the disease was and the discovery of the first case in Yolo County, I decided to take the opportunity in organizing the symposium."
Singh added: "It is incredible how much research has been done on Zika virus in the short amount of time. I am hopeful that in the near future that a vaccine will be developed, but until then we should do everything in our power to prevent this horrible virus from spreading. My concerns are that people may not be well informed which allows the virus to spread even more rapidly."
Said James Warwick, also one of the student organizers: "I think one of the scariest things about Zika in the United States is the lack of public knowledge about it. The scientific community needs to research the virus and develop a vaccine, but can't without funding. And without public pressure, securing funding is going to be slow. Also, the sheer suddenness in which Zika has burst onto the global scene has left both scientific research and public knowledge behind. That is why we are hosting the symposium, to bring the public up to speed, update them on the current research, and to give them the knowledge they need to protect themselves against transmission. As a byproduct, public awareness will increase public pressure to get the world on the right track to stop the spread of Zika."
"The virus itself is extremely alarming," Warwick said. "It can cause extreme neurological and immunological defects, as we see in babies born to infected mothers. But the direct hosts' symptoms usually consist only of temporary pain, rashes, fever, and the like; and only one in four or so people infected with Zika become symptomatic. So there is a very real possibility that a person could be infected, not be aware of it, and potentially pass on the undetected infection to sexual partners or their children. This is made all the more plausible by the fact that many people have never heard of Zika."
Should we worry about the Zika virus? Yes, Leal says, for several reasons: "Zika is likely to become an epidemic in the United States; the virus is transmitted sexually and by infected mosquitoes; and, more importantly, Zika infection in pregnancy causes severe fetal brain development, and other medical problems."
Zika, discovered in 1947, was named after the Zika Forest in Uganda. The first known human case occurred in 1952. “Prior to 2015, Zika virus outbreaks occurred in areas of Africa, Southeast Asia, and the Pacific Islands,” according to the CDC. “In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infection in Brazil. On February 1, 2016, the World Health Organization (WHO) declared Zika virus a Public Health Emergency of International Concern (PHEIC).”
- Author: Kathy Keatley Garvey
That's what UC San Francisco medical student Joshua Lang wrote in his piece, With Summer Coming, Can the Zika Virus Be Contained?, published April 14 in The New Yorker.
Meanwhile, at UC Davis, plans are underway for a public "Zika Public Awareness Symposium," set Thursday, May 26 from 6:30 to 8:30 p.m. in Room 1001 of Giedt Hall.
"It is very important that students and the public-at-large learn how to prevent a possible Zika epidemic as this is the first virus known to be transmitted both sexually and by mosquitoes," said coordinator Walter Leal, a chemical ecologist and professor in the UC Davis Department of Molecular and Cellular Biology. Leal, who collaborates with fellow mosquito researchers in his native Brazil, is the co-chair of the International Congress of Entomology (ICE) meeting, to take place Sept. 25-30, 2016 in Orlando, Fla.
"This symposium is important to host because Zika is a rapidly spreading across the globe so people need to be informed," said Amarita Singh, one of the 18 students organizing the symposium. "Recent studies have shown that this particular virus not only affects pregnant women, but is a threat to all. Since there is no vaccine or medication, it is better to educate now to help prevention."
"I became more aware of the disease when Professor Leal began to discuss it in our biochemistry class, which is what originally sparked my interest," Singh said. "After learning about how dangerous the disease was and the discovery of the first case in Yolo County, I decided to take the opportunity in organizing the symposium."
Singh added: "It is incredible how much research has been done on Zika virus in the short amount of time. I am hopeful that in the near future that a vaccine will be developed, but until then we should do everything in our power to prevent this horrible virus from spreading. My concerns are that people may not be well informed which allows the virus to spread even more rapidly."
Said James Warwick, also one of the student organizers: "I think one of the scariest things about Zika in the United States is the lack of public knowledge about it. The scientific community needs to research the virus and develop a vaccine, but can't without funding. And without public pressure, securing funding is going to be slow. Also, the sheer suddenness in which Zika has burst onto the global scene has left both scientific research and public knowledge behind. That is why we are hosting the symposium, to bring the public up to speed, update them on the current research, and to give them the knowledge they need to protect themselves against transmission. As a byproduct, public awareness will increase public pressure to get the world on the right track to stop the spread of Zika."
"The virus itself is extremely alarming," Warwick said. "It can cause extreme neurological and immunological defects, as we see in babies born to infected mothers. But the direct hosts' symptoms usually consist only of temporary pain, rashes, fever, and the like; and only one in four or so people infected with Zika become symptomatic. So there is a very real possibility that a person could be infected, not be aware of it, and potentially pass on the undetected infection to sexual partners or their children. This is made all the more plausible by the fact that many people have never heard of Zika."
A flier (below) distributed at the campuswide UC Davis Picnic Day noted that the "Zika virus is a risk to all of us, not just to pregnant women." At the May 26th symposium, folks will "learn the symptoms and learn the facts and science about Zika and how you can protect yourself from this disease."
The scientific-based symposium will include "expert panels and speakers throughout the United States and the world, including those working on the front lines of the Zika epidemic." Speakers will be announced soon.
Attendance to the symposium is free, but due to limited space, those planning to attend are asked to RSVP to ucdstudentsagainstzikav@gmail.com
- Author: Kathy Keatley Garvey
Native Brazilian Walter Leal, chemical ecologist and professor in the UC Davis Department of Molecular and Cellular Biology, is there.
So is the mosquito.
At the symposium today, Constancia Ayres, research coordinator of the Oswaldo Cruz Foundation (Centro de Pesquisa Aggeu Magalhaes/FIOCRUZ, considered one of the oldest and most prestigious scientific research institutes in South America), reported that the common southern house mosquito, Culex quinquefasciatus, may be a potential vector of the Zika virus.
Studies in the Ayres lab confirmed that Culex quinquefasciatus infected with Zika (isolated from local patients) showed high transmission rate (as determined by virus replication in the salivary glands).
Of course, these studies were done in the lab, not the field, and this is the beginning of the research.
We asked medical entomologist William Reisen, editor of the Journal of Medical Entomology, and professor emeritus, Department of Pathology, Microbiology and Immunology, UC Davis School of Veterinary Medicine, about this.
"In California less than 3 percent of the Culex including Cx. quinquefasciatus have been found to feed on humans, even in cities like Los Angeles, where humans are the most numerous host," Reisen said in an email. "Therefore, even if they are susceptible to infection, the probability of a female feeding on humans to acquire and then refeed on humans to transmit would be 0.03 x 0.03 = 0.0009 or a rare event indeed. That said, there are areas of the world where quinquefasciatus feeds predominantly on humans in domestic settings. (See his research paper, Host Selection Patterns of Some Pakistan Mosquitoes (U.S. National Library of Medicine, National Institutes of Health).
In his research paper on Pakistan mosquitoes, Reisen mentions Culex pipiens fatigans, now known as Culex quinquefasciatus. Its feeding patterns "varied opportunistically with host availability," he wrote in the abstract. Resting in cattle sheds during the winter, it "fed on birds and bovids, changing to man and bovids during the spring and then to man and birds during summer."
Medical entomologist Thomas Scott, distinguished professor of entomology (now emeritus) of the UC Davis Department of Entomology and Nematology, is a global authority on Aedes aegypti, which transmits dengue, yellow fever, chikungunya and the Zika viruses.
"Vector competence studies in the lab is valuable information, but before we come to the conclusion that Culex quinquefasciatus is an important contributor to transmission of Zika virus, the lab results would need to be confirmed," Scott told us. "Other laboratories and appropriate field studies would need to be carried out in areas where Zika virus is being transmitted to confirm that this species is naturally infected and is regularly biting people. Although it is a potentially important discovery that would change they way we think about Zika virus transmission, it would be wise to carefully explore all of the details necessary to incriminate a mosquito vector before coming to a strong conclusion."
UC Davis medical entomologist Anthony Cornel of the Kearney Agricultural Research and Extension Center and UC Davis Department of Entomology and Nematology, weighed in: "I have to examine the vector competence data carefully to determine its infectivity dose relative to Aedes aegypti. If Culex quinquefasciatus does play an additional role in transmission then it would be of even greater concern because the threat of autochthonous transmission will occur in areas other than where Aedes aegypti is found in California. Culex quinquefasciatus also feed on people but do so at dusk and at night."
"Brazil could be facing a greater fight against the zika virus than previously feared as researchers investigate whether the common mosquito is transmitting the disease," Moraes wrote in the article, headlined "Brazilian Experts Investigate if 'Common Mosquito' is Transmitting Zika Virus."
"The Aedes aegypti species of mosquito was thought to be solely responsible for spreading the virus," Moraes pointed out. "But scientists are now studying whether the Culex mosquito--the variety (species) most commonly found in Brazil--could also be passing on the infection."
Constancia Ayres was quoted as saying: "This may be the reason for the virus replicating faster. The interaction of the mosquito with the virus may explain the epidemiological profile of disease transmission.”
Meanwhile, the headlines continue as research proceeds.
The Outbreak News Today related that researchers in the Ayres lab "are now investigating the possibility that other, non-Aedes mosquito species, might carry and spread Zika and Chikungunya."
"The concern is that the Culex mosquito--which is 20 times more prevalent than the Aedes variety in Brazil-- might also play some role in the rapid spread of these viruses," Outbreak News Today noted. "Researchers hope to have some answers in a few weeks,"
Valor.com.br is hot on the story as well. Reporter Marina Hawk emphasized that the work was done in the lab, but field collection is underway.
