Friday, April 1, 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

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