Florida begins insecticide spraying to kill Zika carrying mosquitoes

Aedes aegypti mosquitoes are seen inside Oxitec laboratory in Campinas, Brazil,

By Julie Steenhuysen

CHICAGO (Reuters) – Florida will conduct an aerial insecticide spraying campaign at dawn on Wednesday in an effort to kill mosquitoes carrying the Zika virus, officials in Miami-Dade County said.

The campaign will cover a 10-mile area that includes the one-mile-square area just north of downtown Miami that health officials have identified as the hub of Zika transmission in the state, the officials said on Tuesday.

On Monday, the U.S. Centers for Disease Control and Prevention issued an unprecedented travel warning, urging pregnant women to avoid travel to the Miami neighborhood at the center of the investigation.

The Zika outbreak was first detected last year in Brazil, where it has been linked to more than 1,700 cases of microcephaly, a birth defect marked by small head size that can lead to severe developmental problems in babies. The virus has spread rapidly through the Americas and Caribbean and its arrival in the continental United States has been widely anticipated.

Florida health officials announced another non-travel related case of Zika on Tuesday, bringing the total to 15.

The aerial spraying campaign was recommended by the CDC in conjunction with the Florida Health Department to reduce adult mosquito populations that might be capable of carrying the Zika virus.

In a conference call on Tuesday, CDC Director Dr. Thomas Frieden expressed concern that vector control efforts so far have not been as effective as hoped. A CDC expert is currently conducting tests in Miami to see if mosquitoes in the area have developed insecticide resistance.

Florida had been using two products in the pyrethroid class of insecticides. In its aerial campaign, the state will use a chemical called Naled that has been approved by the U.S. Environmental Protection Agency, according to Joseph Conlon, a spokesman for the American Mosquito Control Association.

Naled is from a different class of insecticides known as organophosphates. According to the CDC, the chemical has been widely used to control mosquito populations in the United States, including in Miami, Tampa and New Orleans.

The CDC recommended the same chemical for aerial spraying in Puerto Rico, but the recommendation has been met with protests from residents concerned about its impact on health, bees, agriculture and the environment.

Miami-Dade health officials said residents do not need to take special precautions during the aerial spraying activities, but it has recommended that people with known allergies remain indoors.

(Reporting by Julie Steenhuysen; Editing by Leslie Adler)

China’s ‘mosquito factory’ aims to wipe out Zika, other diseases

mosquitoes being released

GUANGZHOU, China (Reuters) – Every week, scientists in southern China release 3 million bacteria-infected mosquitoes on a 3 km (two-mile) long island in a bid to wipe out diseases such as dengue, yellow fever and Zika.

The scientists inject mosquito eggs with wolbachia bacteria in a laboratory, then release infected male mosquitoes on the island on the outskirts of the city of Guangzhou.

The bacteria, which occurs naturally in about 28 percent of wild mosquitoes, causes infected males to sterilize the females they mate with.

“The aim is trying to suppress the mosquito density below the threshold which can cause disease transmission,” said Zhiyong Xi, who is director of the Sun Yat-sen University Centre of Vector Control for Tropical Diseases and pioneered the idea.

“There are hot spots,” Xi said. “This technology can be used at the beginning to target the hot spots … it will dramatically reduce disease transmission.”

Mosquito-borne diseases are responsible for more than one million deaths worldwide every year and Zika has become a concern for athletes at this year’s Olympic Games, which open in Rio de Janeiro on Friday.

Some athletes, including the top four ranked male golfers, have declined to take part.

An outbreak of the Zika virus in Brazil last year has spread through the Americas and beyond, with China confirming its first case in February.

U.S. health officials have concluded that Zika infections in pregnant women can cause microcephaly, a birth defect marked by small head size that can lead to severe developmental problems in babies.

The World Health Organization has said there is strong scientific consensus that Zika can also cause Guillain-Barre, a rare neurological syndrome that causes temporary paralysis in adults.

Sun Yat-sen’s Xi said that several countries had expressed interest in his experiments, especially Brazil and Mexico.

In the laboratory, mosquito eggs are collected from breeding cages containing 5,000 females and 1,600 males and injected with the wolbachia bacteria. Xi’s facility has the capacity to breed up to five million mosquitoes a week.

While a female mosquito that acquires wolbachia by mating is sterile, one that is infected by injection will produce wolbachia-infected offspring. Dengue, yellow fever and Zika are also suppressed in wolbachia-injected females, making it harder for the diseases to be transmitted to humans.

Xi set up his 3,500 square meter (38,000 sq ft) “mosquito factory” in 2012 and releases the males into two residential areas on the outskirts of Guangzhou.

Xi said the mosquito population on the island has been reduced by more than 90 percent.

One villager on the island, 66 year-old Liang Jintian, who has lived there for six decades, said the study was so effective he didn’t have to sleep with a mosquito net any longer.

“We used to have a lot of mosquitoes in the past. Back then some people were worried that if mosquitoes were released here, we would get even more mosquitoes,” he said. “We have a lot less mosquitoes now compared to the past.”

(Reporting by Reuters TV; Writing by Clare Baldwin; Editing by Robert Birsel)

CDC to provide $16 million more to fight Zika locally

Warning of mosquitoes carrying disease by CDC

(Reuters) – The U.S. Centers for Disease Control and Prevention (CDC) is making available more than $16 million to states and territories in their fight against the Zika virus, in addition to the $25 million it had sanctioned in July.

The current Zika outbreak was first detected last year in Brazil, where it has been linked to more than 1,700 cases of the birth defect microcephaly, and has since spread rapidly through the Americas.

U.S. health officials on Monday warned pregnant women to avoid traveling to a neighborhood in Miami after the Florida government said it had identified 10 more cases of Zika caused by the bite of local mosquitoes, bringing the total to 14.

The new funding – for 40 states and territories – will be used to provide real-time data about the epidemic as it unfolds in the United States and help those affected by the virus, the CDC said on Tuesday.

Last month, the agency provided $25 million to 53 states, cities and territories as part of its ‘preparedness and response’ funding to areas at risk for outbreaks.

(Reporting by Natalie Grover in Bengaluru; Editing by Saumyadeb Chakrabarty)

Florida identifies two more Zika cases not related to travel

Aedes aegypti mosquitoes are seen at the Laboratory of Entomology and Ecology of the Dengue Branch of the U.S. Centers for Disease Control and Prevention in San Juan

By Julie Steenhuysen

CHICAGO (Reuters) – The Florida health department said on Wednesday it was investigating another two cases of Zika not related to travel to a place where the virus is being transmitted, raising the possibility of local Zika transmission in the continental United States.

The Florida health department said it has identified an additional case of Zika in Miami-Dade County, where it was already investigating a possible case of Zika not related to travel, and another case in Broward County, where it has been investigating a non-travel related case.

“Evidence is mounting to suggest local transmission via mosquitoes is going on in South Florida,” said CDC spokesman Tom Skinner said.

“These cases fit similar transmission patterns for mosquito-borne diseases such as Chikungunya that we’ve seen in South Florida in years past.”

To confirm whether Zika is being transmitted locally, epidemiologists must survey households and neighbors within a 150-yard radius around the residence of the person who has Zika, which constitutes the flying range of the mosquitoes that carry the virus.

According to the U.S. Zika response plan, Zika transmission is defined as two or more cases not due to travel or sex with an infected person that occur in a 1-mile diameter over the course of a month. Evidence of the virus in local mosquito populations can also be used to confirm local transmission.

Florida heath department officials said investigations into the new cases begins today. The state is urging residents and visitors to participate in requests for urine samples by the department in the areas of investigation. These results will help the department determine the number of people affected.

In addition to the possible cases of non-travel related transmission, Florida on Wednesday reported 328 travel-related cases of Zika. The state is monitoring 53 pregnant women who had Zika infections.

(Reporting by Julie Steenhuysen; Editing by Bernard Orr)

Zika spread, impact ‘scarier than we initially thought’: U.S. health official

Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Disease, speaks about the Zika virus from the White House in Washington

WASHINGTON (Reuters) – The spread and impact of the Zika virus is wider than initially anticipated and the first vaccine candidate for the virus should be available in September, U.S. health officials said on Monday.

Dr. Anne Schuchat, a deputy director of the Centers for Disease Control and Prevention, told reporters the type of mosquito in which the virus is carried is present in more U.S. states than initially thought. She said what authorities are learning about the virus is “scarier than we initially thought.”

Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said at a White House briefing the first Zika vaccine candidate should be available in September.

(Adds dropped word “initially” in quote in headline and second paragraph)

(Reporting by Clarece Polke; Editing by Tim Ahmann)

Zika Spreading in Puerto Rico

A health worker prepares insecticide before fumigating a neighborhood in San Juan

By Julie Steenhuysen

SAN JUAN (Reuters) – The United States faces its first real challenge with the Zika virus on the island territory of Puerto Rico, a part of the nation that is perhaps least prepared to cope with what is expected to be its worst outbreak.

Zika is spreading rapidly in Puerto Rico and is expected to peak in late summer and early fall. By year’s end, public health officials estimate, hundreds of thousands of people will have been infected.

It is the only part of the country that is experiencing a major local outbreak, but the virus is expected to reach southern U.S. states within weeks with warmer temperatures and rising mosquito populations.

Health officials from across the United States are gathering today at the headquarters of the Centers for Disease Control and Prevention in Atlanta to outline a national strategy for combating Zika. In a measure of the concern surrounding the outbreak in Puerto Rico, CDC director Tom Frieden toured the island, meeting with top health officials and local experts last month to assess the situation first-hand.

Puerto Rico is beset with problems already hampering the response: abundant mosquitoes, high levels of insecticide resistance and economic woes that have left vector control in shambles.

“We don’t have good surveillance” here, Frieden said in an interview at the Puerto Rican health department in San Juan during his tour. “We don’t have good control measures.”

First detected in Brazil last year, the Zika outbreak is spreading through the Americas. The World Health Organization declared a global health emergency last month because of growing evidence that Zika can cause microcephaly, a rare birth defect defined by an unusually small head. In adults, the virus has been linked to the typically rare autoimmune disorder, Guillain-Barre syndrome.


Fighting Zika in Puerto Rico is complicated by the toll of a decade-long recession. Nearly half of its 3.5 million residents live in poverty, and mosquitoes are an accepted nuisance. Puerto Rico has seen repeated outbreaks of dengue and more recently, chikungunya. Both viruses are carried by Aedes aegypti, the same species of mosquito that carries Zika.

“Here in Puerto Rico, we’re really starting from square one,” said Audrey Lenhart, a CDC vector control expert in an interview at the CDC’s Emergency Operations Center in San Juan.

In its latest report, the Puerto Rican health department said there are now 350 confirmed cases of Zika infection, including 40 pregnant women.

“We have a very serious combination of problems,” said Dr. Alberto de la Vega, an obstetrician specializing in high-risk pregnancies at San Juan’s University Hospital at the Puerto Rico Medical Center.

“If you don’t have access to money to buy repellent, to sleep with an air conditioner on so mosquitoes won’t bite you, to have mosquito nets around you and you live in areas where there’s more stagnant water, obviously you have higher risks,” he said.

To mitigate the risk of microcephaly among newborns, the CDC and the Puerto Rican government are distributing Zika protection kits to pregnant women that include condoms to prevent sexual transmission from an infected partner, insect repellent, bed nets and larvicide tablets for standing water that cannot be drained.

De la Vega says many locals are resigned to the idea that everyone in Puerto Rico will be infected. He said he won’t accept that people are “surrendering like that.”


Government mosquito abatement resources are scarce, with fewer than a dozen trucks equipped with insecticide sprayers. Of the municipalities that do have trucks, most are used to kill nuisance mosquitoes that bite but do not carry disease, said Manuel Lluberas, a Puerto Rico-born entomologist who works at H.D. Hudson Manufacturing, a maker of spraying equipment.

Lluberas, who advises the WHO and the World Bank on vector control programs, said there are a few municipalities that spray insecticide once every seven to 10 days or once every few weeks. Spraying “needs to be done a lot more frequently” to be effective, he said.

Scientists at CDC’s Dengue Laboratory in San Juan have been testing insecticides on mosquitoes gathered from 17 sites on the island. Frieden said in one of the experiments, mosquitoes placed in bottles coated with a commonly effective insecticide “were happily flying around.”

Eliminating Zika will require spraying insecticide indoors on walls, under beds, behind furniture and inside closets, where Aedes aegypti hide. So far, only two insecticides – deltamethrin and bifenthrin – are approved for indoor residual spraying, and researchers have found high levels of resistance to bifenthrin in Puerto Rico.

Mosquito experts have found similar resistance in parts of Texas and California.

“You find resistance in mosquitoes in one locale, and 20 miles away they are not resistant,” said Joseph Conlon, technical advisor for the American Mosquito Control Association, which represents researchers, public health officials and pesticide makers.

Dr. Janet McAllister, a CDC entomologist, said indoor spraying campaigns will be carried out by local contractors, who will target only areas where the mosquitoes hide instead of coating entire walls, as is typically done to control mosquitoes that carry malaria. “People would not really be coming into direct contact with those surfaces,” McAllister said.

She said the CDC does not plan to use experimental methods, including genetically modified mosquitoes, such as those from Intrexon’s Oxitec now being tested in Brazil, or those infected with Wolbochia bacteria that prevent Zika transmission.

Given the urgency of the outbreak, health officials need to focus on known methods of curbing mosquitoes “rather than doing research on things that may or may not work,” she said.

(Reporting by Julie Steenhuysen; Editing by Michele Gershberg and Lisa Girion)