Mystery Surrounds West Coast Arrival of Zika-Spreading Mosquito

Meet the Aedes aegypti, a tiny blood-sucking mosquito that is causing panic worldwide for its ability to transmit the Zika virus and a host of other diseases that have recently surfaced in the U.S.

The mosquito, on the decline since the 1980s in Southern Florida, suddenly surfaced in California under unknown circumstances in 2013. That year saw a major spike of illegal immigration from Mexico and Central America, where the Aedes aegypti has been spreading dengue fever, chikungunya, and yellow fever viruses that have become pandemic in those regions.

The Aedes aegypti, commonly referred to as the yellow fever mosquito, is recognizable by white markings on its legs and a lyre marking on the insect’s thorax.

The mosquitoes primarily breed in closed-container, damp environments such as unused flowerpots, spare tires, untreated swimming pools, and drainage ditches.

The virus originated in Africa and has been documented off and on in the U.S. for centuries, although the mosquito’s most recent domestic history is fraught with question marks.

The mosquito has been “incriminated as the likely primary vector in historical outbreaks of yellow fever as far north as New York, Philadelphia, and Boston, from the 1690s to the 1820s,” according to academic research.

It has been detected in Florida and some southern states. The climate of South Florida makes the region a good breeding ground and the insect was previously a common disease-spreading vector in the state until the arrival of a rival mosquito, the Asian tiger mosquito, or Aedes albopictus, in 1985.

The Epidemiology and Nematology Department at the University of Florida documents:

Since the introduction of the Asian tiger mosquito in 1985, by way of Texas, the population of Ae. aegypti in Florida has declined dramatically, but still thrives in urban areas of South Florida.

The insect was first detected in significance in California in 2013. Before 2011, the Aedes aegypti was “rarely detected in California and were not known to persist,” related an article from the Emerging Infectious Diseases journal sponsored by the Centers for Disease Control and Prevention (CDC).

The journal documented the mosquito’s arrival on the West Coast:

In 2013, Ae. aegypti mosquitoes were detected in Fresno, Madera, and San Mateo Counties, California; analysis indicated they were genetically most similar to Ae. aegypti mosquitoes from the southeastern United States. In 2014, Ae. aegypti mosquitoes persisted in those 3 counties and were also detected in Kern, Tulare, Los Angeles, and San Diego Counties. In 2015, Ae. aegypti mosquitoes were detected in Imperial, Orange, and Alameda Counties.

In September 2015, the insect was also detected for the first time in San Bernardino and Riverside Counties.

In 2014, the insects were found in offices at San Diego’s 32nd Street Naval Station, the Los Angeles Times reported. The same kind of mosquitoes were found on Oct. 7 and Oct. 8, 2014 in the Los Angeles-area counties of Commerce and Pico Rivera.

The species has since been detected in Tulare, Kern, Imperial, Orange, and Alameda counties.

Another transmitter of similar diseases, the mosquito Aedes albopictus, was detected in Kern and San Diego counties as well as regions of Los Angeles County.

Experts have said the Aedes aegypti mosquito arrived on the West Coast through cargo in ships and airplanes although the exact mode of transportation has not been documented.

Zika spreading ‘explosively’

The mosquito has been spreading the Zika virus, which epidemiologists believe is causing an unprecedented outbreak of infants born with small heads in Brazil. The disease is also associated with developmental delays, seizures, and intellectual disabilities in newborns. Last month, after 2,400 babies were born in the country with microcephaly, a neurological disorder, Brazilian health officials took the unusual step of warning women not to get pregnant.

Besides the possibility of causing birth defects, according to the CDC, the most common symptoms of Zika are fever, rash, joint pain, or conjunctivitis (red eyes).

Other common symptoms include muscle pain and headache. The incubation period (the time from exposure to symptoms) for Zika virus disease is not known, but is likely to be a few days to a week.

The illness is usually mild with symptoms lasting for several days to a week. The symptoms are so close to the flu it may be difficult at first to detect.

The World Health Organization is set to convene an emergency committee in Geneva on Monday to coordinate a global response to the outbreak, with the agency’s head, WHO Director-General Margaret Chan, warning the disease is spreading “explosively.”

The Wall Street Journal viewed the WHO’s announcement as underscoring “the speed with which a virus that began as an obscure tropical malady afflicting Africa and then several remote Western Pacific islands has transformed into a major international health concern, particularly in the Americas.”

Arrival of dengue fever, chikungunya, yellow fever

Besides Zika, the Aedes aegypti also transmits dengue fever, chikungunya, and yellow fever.

Breitbart reported Mexico has been experiencing an alarming rise of chikungunya, a painful and sometimes debilitating infection that could potentially spread across the porous border. And there is already evidence of at least one case arriving from Mexico, as Breitbart documented last month.

In May, the Centers for Disease Control and Prevention added Mexico to the “Watch Level 1” category for chikungunya. In late November, the CDC updated their “Level 1” warning, advising travelers to Mexico to “protect themselves from chikungunya by preventing mosquito bites.”

Local chikungunya transmission began in Mexico in October 2014, with 155 cases confirmed before the end of the year. The numbers skyrocketed in 2015, with 9,952 cases reported in Mexico as of November 8.

According to CDC data, the U.S. in 2015 has seen 571 chikungunya cases in 42 states as of November 17, with all reported cases coming from “travelers returning from affected areas.”

The news media has spotlighted chikungunya in recent weeks after a new study found the disease can cause severe and potentially fatal brain infection, especially in infants and seniors. The report, published in the journal Neurology, examined a 2005-2006 chikungunya outbreak on Reunion Island in the Indian Ocean. Scientists found that the rate of encephalitis among those infected with the chikungunya virus outpaced the rate for all encephalitis reported in the U.S. from 1998 to 2010.

The most common symptoms of chikungunya are fever and joint pain. Other symptoms include headache, muscle pain, joint swelling, or rash.

Migrants, chikungunya and Texas

Missing from the discussion is the potential for illegal aliens to bring in Chikungunya from Mexico. One area to watch is clearly the Texas-Mexico border, where dengue is already endemic.

Indeed, there is at least one case of transmission from Mexico to Texas.

On August 11, 2015, the city of Garland issued the following press release:

On August 11, 2015 the Garland Health Department (GHD) confirmed the first case of imported Chikungunya virus (CHIKV) in Garland in 2015. The individual was infected with the virus during recent travel to Mexico and is no longer contagious.

And Breitbart unearthed a June 2014 dispatch from the Public Health and Environmental Services for Harris County, the most populous county in Texas. The pamphlet on Chikungunya stated, “Global travel, urbanization, immigration, climate, and presence of the mosquito species known to transmit these diseases in Harris County are all factors that contribute to the possibility of these diseases emerging in our area.”

On July 7, 2014, the Texas Department of State Health Services confirmed the first human case of the disease, reportedly an individual who had traveled to the Caribbean.

Two days later, a second case was confirmed, this time in an 18-year-old woman who had returned from a trip to Haiti. By July 23, 2014, a “handful of Texas residents” were identified as being infected with the chikungunya in five Texas counties. The next month, Texas was home to at least 14 cases.

Nationwide that month, cases in New Jersey more than doubled to 25; New York confirmed 44 cases, and Florida saw a marked increase.

These cases came before the Mexico Chikungunya outbreak reached a “Level 1” CDC threat.

The World Health Organization documented a previous case in which infected migrants introduced chikungunya in 2007 in a coastal village in Italy, sparking an outbreak of 197 cases.

In June 2012, Scientific American discussed the disease, as well as other illnesses such as Chagas and dengue fever in the context of possible transmission via illegal aliens crossing the border. “Since undocumented immigrants are difficult to track, officials have a hard time measuring and treating infected individuals,” the magazine reported.

With research by Brenda J. Elliott.

Aaron Klein is Breitbart’s Jerusalem bureau chief and senior investigative reporter. He is a New York Times bestselling author and hosts the popular weekend talk radio program, “Aaron Klein Investigative Radio.” Follow him on Twitter @AaronKleinShow. Follow him on Facebook.


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