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A mainland thing?

A mainland thing?

I’ll probably catch flak for this but, being Caucasian myself, those panhandlers standing on the side of roadways with cardboard signs asking for money, is this a mainland Caucasian thing?

Seems that people of this particular ethnic group are the only ones out there doing this.

Happy holidays.

Rick LaMontagne

Hilo

Weak leadership

The whole Thirty Meter Telescope drama reminds me how lacking our leadership is, at both the state and county level.

There are so many issues facing the state and county, but the “leaders” of each — Gov. David Ige and Mayor Billy Kenoi — are either absent or ineffective. Or both.

With an election comping up next year, I hope we’ll all look carefully at what sort of leadership we need, and remember what sort of “leaders” we should never hire again.

It’s a depressing time for our Aloha State.

A. Yamamoto

Hilo

Mosquitoes and dengue

There are two mosquitoes in the world most responsible for infecting people with dengue: Aedes aegypti and Aedes albopictus. All the Hawaiian Islands have Aedes albopictus. The latest research (2002) shows that Aedes aegypti is only on the Big Island, along the coast from Puna to Kawaihae, up to at least 2,000-foot elevation.

In the past, all the islands had A. aegypti as well. But the all-out vector control effort on Oahu in 1943 and the DDT spraying on all the islands in the ’60s got rid of them everywhere, with the possible exception of the Big Island. No one knows how or why they remained on, or returned to, the Big Island.

Some people think A. aegypti is a more efficient vector for dengue since it prefers human blood to other mammals. However, in some places, in the absence of A. aegypti, A. albopictus (which likes all mammal blood) is spreading dengue all by itself. For example, Maui has no A. aegypti and had a dengue outbreak in 2001. There also have been epidemics of dengue in parts of China and Japan with no A. aegypti.

A. aegypti originally is from North Africa (hence “aegypti”) and arrived in Hawaii in about 1892, probably from water in the hold of a ship. A. albopictus is from Southeast Asia and arrived in Hawaii about 1896, also probably in the hold of a ship. Only a few years later, in 1903, Hawaii had its worst dengue epidemic — 30,000 people in Honolulu had the disease, or approximately one-third of the city’s population.

The genus name, Aedes, is a Greek word meaning “unpleasant” or “odious.” The species name, albopictus, means white-painted. All Aedes mosquitoes are white- striped and are difficult to tell apart. If you look at the thorax of A. aegypti with a magnifying glass, you will see a lyre-shaped white marking (two curved lines with two straight lines inside). The thorax of A. albopictus has a single straight white line.

The same two Aedes mosquitoes also pass on the viruses for three other serious diseases: yellow fever, chikungunya and zika. When a yellow fever vaccine was invented in the 1950s, governments started to defund their mosquito control programs. That’s when dengue started to take off. Now dengue, chikungunya and zika are sweeping the world. Dengue is common in 110 countries. Now it is our turn if we don’t control these two mosquitoes.

Both mosquitoes lay their eggs in small containers, plants or cup-like structures that hold water. What makes them especially difficult to eradicate is that they lay their eggs above the waterline. The eggs hatch when the water rises and covers them — like when it rains or when someone adds water to a container. So even after a thorough spraying to kill all the adults and larvae in an area, the eggs can live on for more than a year.

And last, but unfortunately not least, the latest research on mosquito transmission of the dengue virus shows that people who are bitten by a dengue-infected mosquito don’t have to be symptomatic to re-transmit the virus back to other mosquitoes.

A 2015 paper titled, “Asymptomatic humans transmit dengue virus to mosquitoes” (www.pnas.org/content/112/47/14688.full.pdf) has two frightening conclusions.

First, a person who is bitten by a dengue mosquito can infect other mosquitoes before the person has symptoms of the disease. And second, people who are bitten by dengue mosquitoes and never have symptoms, also can pass the virus to new mosquitoes. If these conclusions are true, it will make dengue much harder to contain than our government agencies expect.

Matt Binder

Waimea