Author Archives: bigbadvirus

To understand more about Zika virus infection, CDC established the US Zika Pregnancy Registry and is collaborating with state, tribal, local, and territorial health departments to collect information about Zika virus infection during pregnancy and congenital Zika virus infection. The data collected through this registry will be used to update recommendations for clinical care, to plan for services for pregnant women and families affected by Zika virus, and to improve prevention of Zika virus infection during pregnancy.


At A Glance - Zika in the U.S.

US States
Travel-associated Zika virus disease cases reported: 258.
Locally acquired vector-borne cases reported: 0.
Of the 258 travel-associated infections, 18 are in pregnant women and 6 were sexually transmitted.

US Territories
Travel-associated cases reported: 3.
Locally acquired cases reported: 283.
Of the 283 locally acquired infections, 35 are pregnant women.


Oxitec is applying to release sterile mosquitoes that are programmed to create self destructing progeny. The sterile insect technique has been used over the last 50 years in a number of countries for controlling insects. Normally, these released insects are males. Releasing males is attractive because they aren't the ones that bite. The sterile males compete with wild males for the females.

Oxitec Limited developed a program to control mosquitoes, which is based on the sterile insect technology. This program involves the production of genetically engineered male mosquitoes, known as OX513A Aedes aegypti that possess a fluorescent marker and a conditional lethality characteristic. The goal or releasing these engineered mosquitoes is to reduce the local population of Aedes aegypti.

The genetically engineered Aedes Aegypti were developed to reduce mosquitoes in Florida. The engineered mosquito has not been approved for use until now. The conditional lethality is this mosquito larva requires tetracycline to live. Oxitec Limited plans to rear millions of male mosquitoes each week. The mosquitoes would be released and breed with wild mosquitoes. In the lab, when the larvae of the mosquito are given tetracycline it serves as a remedy for the self-limiting gene. When in the wild, without tetracycline, the genetically engineered progeny of OX513A (Aedes aegypti) will not reach adulthood.

OX513A has been approved for import and contained testing in Brazil, Cayman Islands, France, India, Malaysia, Singapore, Thailand, USA and Vietnam. Field trials are currently also underway in Brazil.

Thomas Masterson MD, editor,


Zika risk at high elevations
What is the risk of getting Zika at high elevations?
The mosquitoes that spread Zika usually do not live at elevations above 6,500 feet (2,000 meters). Travelers who plan to be only in areas above this elevation are at a very low risk of getting Zika from a mosquito. Travelers are still at risk of sexual transmission of Zika from a male partner who has been in areas with local transmission.

What if I am flying into an airport at a low elevation in an area with Zika but then immediately driving to a high elevation?
You would still be at risk of getting Zika from a mosquito bite while you were at the low elevation. You should strictly follow steps to prevent mosquito bites while in these areas.

I am going to an area that looks like it is in the high-elevation zone, but your map is not detailed enough for me to see for certain. Is this destination in the risk area?
Talk to your doctor about your risk of Zika in the area where you are traveling. Travelers to destinations that cross or are near an elevation border may consider the destination as an area of lower elevation and follow recommendations for travel to areas with Zika.

What source of elevation data did you use to create the maps? Where can I look up elevation data for my destination?
Most of our maps were made based on the Global Multi-resolution Terrain Elevation Data 2010 (GMTED 2010), and for small countries we used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) elevation dataset. The US government does not maintain or endorse a specific elevation lookup service, but various resources can be found on the internet.

What data sources did you use to show that mosquitoes do not usually live above 6,500 feet?
Aedes species mosquitoes, the mosquitoes that carry Zika, live in areas with certain ecological conditions (temperature, rainfall patterns, local plant growth, and human population density). CDC used elevation data to predict areas where the Aedes mosquitoes are unlikely to live. Our findings show that Aedes mosquitoes are not usually found above 6,500 feet (2,000 meters).

What do you recommend for pregnant women who decide to travel to high elevations in an area with Zika?
The risk of getting Zika from a mosquito at elevations above 6,500 feet (2,000 meters) is minimal. However, traveling through an area of low elevation or stopping, even briefly, in a low elevation area on the way to higher elevation increases the risk of getting Zika from a mosquito, and pregnant woman should strictly follow steps to prevent mosquito bites while in these areas. Pregnant women traveling to these areas should use condoms or not have sex with men who may have traveled to lower elevations in an area with Zika. Pregnant women should also be alert to changes in their travel plans that may take them to elevations below 6,500 feet.

Besides Zika, is it safe for pregnant women to travel to high elevations?
The low oxygen levels found at high elevations can cause problems for travelers who are going to elevations above 8,000 feet (2,400 meters). The best way to prevent altitude illness is to ascend slowly and take time to get used to the lower oxygen levels. Pregnant women should avoid strenuous activities at high elevations, and some doctors recommend that pregnant women not spend the night at altitudes above 12,000 feet (3,650 meters). Pregnant women should also consider whether they will have access to medical care at a high-elevation destination.


A multidisciplinary group of experts convened by the Pan American Health Organization / World Health Organization (PAHO / WHO) is in El Salvador this week to exchange experiences and support national efforts to respond to the Zika virus outbreak in the country.

The experience of Brazil in the management of microcephaly and Guillain-Barre Syndrome is being shared during this mission, along with discussions on surveillance protocols and the preparation of health services for surveillance and patient care, particularly for those with severe neurological manifestations related to Zika.

Since Brazil reported the first cases of local transmission of Zika in May 2015, the virus has spread to 31 countries and territories in the Americas, a situation that is compounded by possible association of Zika with microcephaly and Guillain-Barre syndrome. Brazil, Colombia, El Salvador, Surinam and Venezuela have all documented increases in cases of the syndrome.

El Salvador has reported more than 9,000 cases of Zika virus infection so far, and 138 cases of possibly associated Guillain-Barre syndrome. Of these cases, 70 percent have already been released and 228 pregnant women are being tracked. Among those women, 35 have given birth to children without microcephaly and the rest are being followed, country authorities said.

PAHO has developed a strategy to help countries mitigate the impact of Zika virus, through strengthening their capabilities to detect the introduction and spread of the virus, reducing mosquito populations, ensuring the necessary health services, and communicating effectively with the public about risks and prevention measures.


International experts, convened by WHO, have agreed on top priorities to advance R&D for Zika medical products.

The following tools were prioritized as the most viable options to help fight the spread of Zika virus in the immediate future:

Multiplex tests for ‘flaviviruses’ (viruses related to Zika, such as dengue, chikungunya), in addition to more traditional tests; protective vaccines based on killed virus (or other non-live) preparations for women of childbearing age; and innovative vector control tools that reduce the mosquito population.  “Zika virus induces a mild and mostly harmless infection in the majority of patients,” indicated Dr Marie-Paule Kieny, Assistant Director-General in charge of R&D at WHO. “For that reason medicines to treat it seem less of a priority at this stage. The most pressing need is the development of diagnostic and preventive tools to address the current R&D gap and protect pregnant women and their babies.”

As of 2 March, 67 companies and research institutions were already working on a number of products (31 on diagnostics, 18 on vaccines, 8 on therapeutics, 10 on vector control), which are at various stages of early development. No vaccine or therapeutic has yet been tested on humans.


Experts agreed that the development of a vaccine is a major priority to respond to epidemics in the future. Vaccination of pregnant women and women of childbearing age is the main target, and pragmatic strategies will be needed to fast-track the development of a safe and effective product.

Work is underway for the development of an emergency vaccine target product profile. The target product profile will serve as a guide to consult and build consensus on regulatory requirements for Zika vaccine evaluation and registration. A draft target profile will be submitted to a public consultation in the coming weeks, with a view to having a final profile in May.


Over 30 companies are working on or have developed potential diagnostic tests. There is general support for the development of a target product profile for a multiplex test that can diagnose dengue, chikungunya and Zika viruses. A first draft is ready and this too will undergo public consultation before finalization in mid-April.

WHO continues to encourage manufacturers to apply to the WHO Emergency Use, Assessment and Listing procedure for a quality and performance evaluation of their products.

Emergency use assessment and listing procedure for Zika virus disease
Vector control

Vector control experts have clearly stated that as traditional interventions – such as insecticide spraying – have not had significant impact on dengue transmission the same might apply to Zika. They also cautioned that extreme rigour needs to be applied in evaluating novel tools, such as Wolbachia, recombinant and irradiated mosquitoes. An emergency meeting of the WHO Vector Control Advisory Group next week will fine-tune evaluation methods and a target product profile for innovative techniques


The U.S. Department of Health and Human Services announced that it is arranging and funding shipments of blood products from the continental United States to Puerto Rico. The mainland blood is being provided to ensure an adequate supply of safe blood for island residents as the Commonwealth of Puerto Rico experiences active mosquito-borne Zika transmission.

The risk of Zika virus transmission through blood products is considered likely based on the most current scientific evidence and what is currently being reported about transfusion-associated infection occurring outside of the United States. Blood products shipped to Puerto Rico will be collected from areas in the continental United States without active transmission of Zika virus so that blood products used in Puerto Rico can meet all of the same high safety standards as those used elsewhere in the United States.

The shipments are being provided to Puerto Rico through the American Red Cross, the Blood Centers of America, and America’s Blood Centers. Existing blood collection centers in Puerto Rico will then supply that imported blood to transfusion providers.

“Availability of safe blood products for the residents of Puerto Rico is a major priority for HHS,” said Karen B. DeSalvo, M.D., M.P.H., M.Sc., HHS acting assistant secretary for health. “We are arranging the importation of blood products from areas unaffected by local Zika transmission to ensure the safety of Puerto Rico’s blood supply."

The U.S. Food and Drug Administration (FDA) recommends that whole blood and blood components for transfusion be obtained from areas of the United States without active transmission of Zika virus until a blood donor screening test or pathogen reduction technology (where applicable) for Zika virus becomes available.