Zika, baby--is not your friend.

There’s Zika in our future. Count on it.

You’ve read lots about the Zika virus, another in the toxic deck of playing cards dealt by the Aedes aegypti mosquito, the yellow fever mosquito. Others include Dengue, Yellow Fever and Chikungunya. 

Zika can also be carried by the Aedes albopictus mosquito, the Asian tiger mosquito.

We’ve got them in Hawai`i. Lucky Hawai`i, we are one of the first places on the planet to be invaded by both. They are both alien invaders. In pre-human Hawai`i, there were no native mosquitoes.

So far, only one person is known to have arrived in the islands with Zika, and it appears not to have spread from that case. The most likely source of the virus is in travelers returning from areas where the virus is rampant.

It’s in Samoa, and almost anywhere in the tropical and subtropical Americas. How widespread is it in the Americas? Check this list: Barbados, Bolivia, Brazil, Colombia, Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname, U.S. Virgin Islands, Venezuela.

Oh, it just got reported this week in Jamaica.

There’s a lot of information about Zika at this Centers for Disease Control (CDC) site. 

Zika is in a class of disease-causing organisms called flaviviruses. They include West Nile virus, dengue fever, tick-borne encephalitis and others.

The upshot is that the disease is not that big a deal for adults—certainly nowhere near as painful and symptom-filled as the dengue fever that’s now running through the Big Island. Primary symptoms are fever, rash, joint pain, or conjunctivitis (red eyes), muscle pain and headache. And most infected people—four out of five—have no obvious symptoms at all (although presumably they can still spread the disease.)

However, there are concerns that in some people an infection with Zika could lead to Guillain-Barré Syndrome, an immune system disorder. CDC notes that there are increased cases of Guillain-Barré in Zika infections, but they haven’t confirmed the relationship.

Same thing with birth defects. Pregnant women who get Zika in Brazil seem to have an increased rate of children born with microcephaly, or abnormally small heads, “and other poor pregnancy outcomes,” CDC says. There’s still far more to learn, but women are encouraged to avoid Zika infested areas if pregnant, or if likely to become pregnant, and to use precautions if they must be there. 

Here are the precautions, but the basic rule is to do everything you can to avoid being bitten by a mosquito, including chemical mosquito repellants and protective clothing. 

World Health Organization Director-general Margaret Chan last week convened an emergency panel, to meet Feb. 1, 2016, to look into the association between Zika and birth defects and Guillain-Barré. Here is her statement.

And there are all sorts of conspiracy theories running around already, as there were about AIDS and Ebola. One of them is that genetically modified mosquitoes are somehow involved in transmission.

The opposite is true. A number of initiatives are being used to determine whether genetically modified mosquitoes can be used to stop the virus, but they are happening after Zika already burgeoned. And a test of a genetically modified mosquito in one Brazilian city, Piracicaba, appears to have protected many residents there.

Zika appears to have changed its character and become more of an epidemic and less of a rare and isolated disease as much as 10 years ago, long before genetic modification techniques on mosquitoes were being attempted in Brazil. 

To be clear, Zika was first identified in 1947 in the forests of Uganda in monkeys. It was found in 1952 in humans in Uganda and Tanzania. It popped up occasionally here and there as people moved it around the globe. It got to Southeast Asia in 1966, and by 1970 was in India, Pakistan, Indonesia and Malaysia.

It first appeared in the Pacific in Yap with a couple of hundred cases in 2007. 

Zika had been rare and isolated before Yap. The Yap case was the first to be described as an outbreak.

The New England Journal of Medicine described the Yap cases in a paper in 2009. 

“The virus could have been imported by a person with undetected infection. Serologic evidence of Zika virus infection in humans has been reported in the Philippines, and travel between Yap and the Philippines is common,” the journal article said.

In an ominous bit of prediction, the 2009 paper warned that this disease, the way it was behaving on Yap, was a threat throughout the Pacific as well as the Americas. 

“The accessibility of air travel and the abundance of mosquito vectors of flavivirus in the Pacific region raise concern for the spread of Zika virus to other islands in Oceania and even to the Americas,” the paper said.

The outbreak in Tahiti/French Polynesia four years later was the largest known Zika flare-up in history.

One suggestion is that Tahitian canoe paddlers competing in the Va`a World Sprint Championship in Rio brought it to Brazil in August 2014. Here is a report on that. 

It seems to be spreading in Brazil with the same ferocity as it did in Tahiti. It was reported as a full-fledged outbreak by mid-2015. 

Here is a World Health Organization fact sheet on Zika. 

Here is a fact sheet for health professionals on Zika from the European Centre for Disease Prevention and Control. 

How bad could it be?  In Tahiti in 2013, 35,000 suspected cases were reported, although far fewer were confirmed. There are fewer than 300,000 people in all of French Polynesia--so more than 10 percent of the population was possibly impacted.

Brazil alone has more than 200 million people, and the rest of South America has nearly that number. The World Health Organization reported Zika is spreading explosively through the Americas. 

 

© Jan TenBruggencate 2016

Zika: forget conspiracies, birth defects clearly linked to the virus

Zika virus continues to rampage through South and Central America and the Caribbean, and new data is clarifying its link to severe birth defects in the children of women infected during pregnancy.

Zika, born in Africa, has spread through the Pacific, and in the last few years into South America. Most recently the Centers for Disease Control and Prevention placed travel restrictions on two small Caribbean islands, Aruba, Bonaire. With those, Zika is now known to have affected 28 areas through the continent. 

There has been considerable discussion about birth defects like malformed brains and tiny heads having been caused by something other than Zika—including some of the mosquito control technologies that have been used to attempt to control the mosquito-borne virus.

This blog previously discussed Zika six weeks ago here.

As we wrote then, “And there are all sorts of conspiracy theories running around already, as there were about AIDS and Ebola. One of them is that genetically modified mosquitoes are somehow involved in transmission.”

Most of the latest data is discounting other causes and more and more clearly targeting Zika as the direct cause of the birth defects. Indeed, the correlation between Zika and microcephaly  dates back to before the South American outbreak.

The journal The Lancet today (March 19, 2016) reports that microcephaly is quite clearly linked to a 2013 to 2014 outbreak of Zika in French Polynesia—the biggest outbreak in the world before the current South American panic.

The study found a spike in microcephaly cases among the children of women who had been infected with Zika during the first trimester of their pregnancies.

“Our analysis strongly supports the hypothesis that infection in the first trimester of pregnancy is associated with an increased risk of microcephaly,” wrote Dr. Simon Cauchemez, of the Pasteur Institute in Paris, and co-authors.

The data could not prove a link among women who were infected after the first trimester: “We could not rule out an increased risk of microcephaly from infection in other trimesters, but models that excluded the first trimester were not supported by the data.”

The French Polynesian study found that the actual risk of having a child with microcephaly is comparatively low—about 1 percent—among mothers in the first trimester. However, since the percentage of people who get infected by Zika can be very high—in French Polynesia, two-thirds of the people were infected—it can still be a significant public health hazard.

“Our findings support the need for a strong and prompt response to protect, inform, and monitor pregnant women and to provide strong research agendas to clarify the causal link between Zika virus and microcephaly and develop effective treatments and vaccines,” the authors wrote.

Zika virus has been found in the amniotic fluid of two pregnant women who had been infected with Zika, according to a Feb. 11, 2016 paper in the journal of the Center for Infectious Disease Research and Policy. 

A March 10, 2016, paper in the New England Journal of Medicine, said researchers had recovered Zika virus DNA from the brain of a microcephalic fetus. The mother was living in Brazil, and she reported Zika-like symptoms during that period.

A number of conspiracy theories have suggested microcephaly might be caused by genetically modified mosquitoes that were released to control Zika, or by a pesticide, pyriproxifen, released to control the mosquitoes, or that it was caused by vaccines. 

A study published March 8, 2016, by the New England Complex Systems Institute, downplayed either possibility.

The study said the argument for any other causes than Zika is weakened by the presence of increased microcephaly in French Polynesia, where genetically engineered mosquitoes, pyriroxifen and the implicated vaccine were not widely used.

© Jan TenBruggencate 2016

New Zika research: It just keeps getting worse

Hawai`i continues to be on the alert for Zika virus, and there are increasing good reasons for concern.

Here are some updates on Zika virus.

The Centers for Disease Control and Prevention have confirmed the link between the mosquito-borne disease and babies born with shrunken heads, a condition called microcephaly.

Here’s the ScienceDaily piece on that. 

 The report from CDC was published in the New England Journal of Medicine under the title,  “Zika Virus and Birth Defects — Reviewing the Evidence for Causality.” The original paper is here.

There’s a caveat here. This isn’t original research, but a review of the original research done by others, and it concludes that, considered as a whole, the connection is inescapable. 

Here is the language they used: “we evaluated available data using criteria that have been proposed for the assessment of potential teratogens. On the basis of this review, we conclude that a causal relationship exists between prenatal Zika virus infection and microcephaly and other serious brain anomalies.”

In adults, Zika has been associated with a neurological disease called Guillain-Barre Syndrome. Now, another new paper suggests that adults with Zika are also at risk for a rare autoimmune disorder, acute disseminated encephalomyelitis.

The connection between Zika and this brain disease is still not entirely locked up. Brazilian researchers found 151 cases of brain disorders among Zika patients. Only a very few came down with acute disseminated encephalomyelitis. 

The paper on this was presented this week to the conference of the the American Academy of Neurology. The ScienceDaily story on it is here. 

It is, once again, not a smoking gun, but there are reasons for concern, and there are worries about why and how Zika attacks the brain. 

“Clinicians should be vigilant for the possible occurrence of (acute disseminated encephalomyelitis) and other immune-mediated illnesses of the central nervous system," said James Sejvar, with the Centers for Disease Control and Prevention.

There have been suggestions that Zika may not only be transmitted by mosquito, but that it might be spread directly between humans through sexual activity. A new French study, reported in the New England Journal of Medicine and here on EurekAlert,  confirms it.

"Their analyses have shown 100% genetic correlation between the form of the virus present in a man who contracted the virus in Brazil and that of a woman who had never travelled in the epidemic area, but who had sexual relations with him," the EurekAlert article said.

Oh, and here's an interesting piece, also in ScienceDaily, about a new mosquito trap, developed by Canadian and Mexican researchers, that may help reduce the populations of the Aedes mosquitoes that carry Zika.

See RaisingIslands’ previous posts on Zika here.

© Jan TenBruggencate 2016

Dengue, Zika, and now Yellow Fever? Mosquito-borne plagues are growing

The Aedes mosquito is responsible for the dengue fever outbreak that’s been terrorizing the Big Island, and the zika virus that has infected several Hawai`i residents while traveling, and now another Aedes passenger, yellow fever, is spreading.

Yellow fever is famously the disease that killed thousands during the construction of the Panama Canal in the early years of the last century. Malaria, another of the major disease of the Panama Canal construction, is caused by a different mosquito genus, Anopheles.

The worst effects of those diseases around the Canal Zone were controlled by aggressively draining swamps, pouring kerosene on any standing water, and installing domestic water systems, so catchment rain barrels could be replaced. The barrels were perfect mosquito breeding areas.

Hawai`i has the Aedes mosquito, and has had several dengue fever outbreaks. Recently, with the spread of zika virus from Africa to Asia, across the Pacific and into the Americas, the mosquitoes are responsible for a new disease outbreak.

And now, another Aedes-carried disease is breaking out. Yellow fever, which has been a constant threat in some parts of the tropical world, has taken a turn for the worse in Africa, and has spread to China.

The medical journal, The Lancet, has just published a new paper, Yellow Fever: A Global Reckoning, calling it a “global health security risk.” 

The new outbreak started in 2015 in Angola, and has spread to the Democratic Republic of Congo, Kenya and China. Vaccines against yellow fever have run out in Angola. Unlike dengue and zika, there is a vaccine that provides lifelong protection.

Yellow fever can present with flu-like symptoms—fever, chills, severe headache, muscle pain, nausea, vomiting and fatigue. Most people recover, but 15 percent develop liver damage, jaundice, organ failure and in some cases death. The disease gets its name because of the yellowed skin and yellow eye whites of people with severe cases.

During the late 1800s and the first decade of the 1900s, sailors referred to the disease as Yellow Jack, and reportedly were more afraid of it than any other disease.

A case of yellow fever came to Hawai`i with a visitor, who was immediately quarantined. The disease may have spread to one additional person, a quarantine guard. Because of the Panama Canal yellow fever crisis, health officials were aware of the disease, and knew how to set up an effective quarantine.

Meanwhile, in news about Zika, which has been found in Hawai`i residents who caught it while traveling abroad, there are not reported cases of local transmission. Zika has been reported on several islands, all in people who had traveled to zika-infested areas. In January, a Hawai’i woman who had traveled to Brazil gave birth to a child with birth defects.

In addition to birth defects among a small percentage of infected pregnant women, zika has been linked to Guillain-Barre syndrome, and recently with another attack on the nervous system, acute myelitis.

For more information see our previous pieces on zika: Zika,not your friend, and Zika and birth defects. 

You can also search our blog for several articles on dengue. Here was the first, from last November. 

© Jan TenBruggencate 2016

Zika now spread by at least two Hawai`i mosquito species

Aedes aegypti biting a human.
(Modified USDA image.)

 Mosquitoes are not native to Hawaii, but we’ve got them, and new evidence is that they’re growing increasingly dangerous.

The Zika virus can be spread by at least two Hawai`i mosquitoes, including one of the most common species in the Islands.

We’ve got eight mosquito species now—there’s a list at the bottom of this post. Some diseases are spread by only one species—but that’s changing.

For example, it used to be believed Aedes aegypti, which has limited distribution in Hawai`i. But now Florida researchers working in Brazil found it has spread to the Asian tiger mosquito, Aedes albopictus, which is everywhere in the Islands.

that the Zika virus could only be spread by the Yellow fever mosquito,

Dozens of American babies have been born with severe birth defects associated with Zika, and the number of cases is growing. 

The most common defect is a deformed brain. Hawai`i has had 16 reported cases of Zika, according to the U.S. Centers for Disease Control.

Here’s the Science Daily report on Zika’s new host. 

“"These results are important because they are the first to show that Aedes albopictus can be infected with Zika virus RNA," said Chelsea Smartt, a faculty member at the UF/IFAS Florida Medical Entomology Laboratory in Vero Beach, Florida. "Also, this study found Zika virus RNA in male mosquitoes, which we can infer also means the Zika virus RNA came from the mother. We need to determine if live Zika virus can also be transmitted in Aedes albopictus."

And there is evidence that a number of other mosquitoes may also be capable of transmitting Zika, says the paper, which can be read here. 

Not to make too much of this, but two key weapons in attacking mosquito-borne illness are targeted insecticides and genetic modifications to impact mosquito populations. And in Hawai`i, both insecticides and genetic modification are being targeted by activists for entire bans or limitations on use of these products and technologies. Thus far, the Legislature and the courts have held off these movements.

Hawai’i’s four mosquito species that bite in the daytime are Aedes albopictus (Asian tiger mosquito), Aedes aegypti (Yellow Fever mosquito), Aedes japonicus (Asian bush mosquito), and Wyeomyia mitchelli (Bromeliad mosquito).

The two that bit at night are Culex quinquefasciatus (Southern house mosquito) and Aedes vexans (Inland floodwater mosquito).

There are a couple of other mosquitoes that don’t bite humans, so we won’t worry about them for this article.

More about these critters in the Islands at this Departmentof Health site. 

© 2017 Jan TenBruggencate