About | HeinOnline Law Journal Library | HeinOnline Law Journal Library | HeinOnline
LOG IN
LOG IN

1 Tadlock Cowan, Genetically Engineered Mosquitoes: A Vector Control Technology for Reducing Zika Virus Transmission 1 (2016)

handle is hein.crs/crsnalcaaaap0001 and id is 1 raw text is: ,.., 'Congressional Research Service August 22, 2016 Genetically Engineered Mosquitoes: A Vector Control Technology for Reducing Zika Virus Transmission Background In February 2016, the World Health Organization (WHO) declared Zika virus a public health emergency of international concern. WHO defines such a public health emergency (1) to constitute a public health risk to other states through the international spread of disease, and (2) to potentially require a coordinated international response. This definition implies a situation that is serious, unusual, or unexpected; carries implications for public health beyond the affected state's national border; and may require immediate international action. (See CRS Insight IN10433, Zika Virus: Global Health Considerations.) While only about one out of five persons infected with Zika virus exhibit even the common symptoms of mild fever, rash, and joint pain, the U.S. Centers for Disease Control and Prevention (CDC) have confirmed that Zika-infected pregnant women are at risk for delivering babies with microcephaly, a birth defect of the cerebral cortex where a baby's head is smaller than expected when compared to babies of the same sex and age. While research is limited, pregnant women are considered at risk for delivering babies with microcephaly no matter the stage of their pregnancy when they become infected with Zika virus. (See CRS Report R44368, Zika Virus: Basics About the Disease.) Zika virus has now triggered outbreaks in 33 countries and territories, although confirmed cases linking Zika virus to babies with birth defects have thus far been seen in only Brazil and French Polynesia. Several countries have also reported a spike in cases of Guillain-Barr6 syndrome, a neurological syndrome, also believed to be an effect of the virus in some victims. A Mosquito-Borne Virus Zika virus (so named for the Zika forest in Uganda, where it was first identified in monkeys in 1947) is a mosquito- borne flavivirus that has rapidly infected human populations in Latin America and the Caribbean, including outbreaks in the U.S. territories of Puerto Rico, the U.S. Virgin Islands, and American Samoa. As of April 2016, over 400 cases in the United States have been confirmed, each acquired through either travel to areas where the mosquito vectors for Zika virus circulate or sexual contact with people who had traveled to such areas. No confirmed cases of local transmission have been confirmed in the contiguous United States as yet. The first outbreak of Zika virus outside Africa, Asia, and the Pacific Islands occurred in Brazil in May 2015. The virus is spread predominantly by the female Aedes aegypti mosquito (and to a less effective extent by Aedes albopictus), an aggressive day-biter that is also a vector for yellow fever, dengue, and chikungunya. Aedes aegypti mosquitoes are non-native to the United States. A model created by Toronto researchers found that approximately 63% of the U.S. population lives in areas where Zika virus might spread during seasonally warm months if mosquitoes in the United States were to become vectors of Zika virus. As much as 7% of Americans live in areas where the cold might not kill off the mosquito in the winter, leaving them vulnerable year round. (See CRS InFocus 10353, Mosquitoes, Zika Virus, and Transmission Ecology.) No vaccine exists for Zika, and scientists have estimated that it could take two years or more to develop such a remedy. Mosquito control and bite prevention are the first lines of defense. Controlling Aedes aegypti by conventional methods such as truck and aerial spraying is only moderately effective in reducing mosquito populations- approximately 30%-50%-in part owing to the resistance the mosquitoes have developed to the more commonly used insecticides and to the limited area in which Aedes aegypti mosquitoes circulate (100-200 yards from where the larvae emerge). Aedes aegypti mosquitoes also tend to favor house interiors where spraying/fogging is not practical. Strategic placement of several low-cost autocidal gravid ovitraps (which mimic breeding sites) in house interiors can reduce the Aedes aegypti population by about 50%. Further contributing to the urgency of the pandemic, the El Niio weather phenomenon in 2015-2016 brought warmer temperatures and moisture to the regions most affected by Zika virus, and with that weather pattern, a potential increase in the population of Aedes aegypti mosquitoes. 0X5 I 3A Genetically Engineered losquitoes In this environment, the creation of a genetically engineered (GE) Aedes aegypti mosquito by the British firm Oxitec in 2002, known as OX513A, is generating significant interest among public health officials. Developed originally to suppress the incidence of dengue fever, OX513A is now regarded as a promising technology to reduce the incidence of Zika virus transmission by reducing the population of mosquitoes. Oxitec is owned by Maryland-based Intrexon Corporation. Oxitec's OX513A are mosquitoes that have been genetically engineered with a dominant transgene that produces a lethal protein that ties up the transcriptional machinery in the cells. The gene is passed on to the mosquito's offspring so that they die before reaching adulthood. Each OX513A mosquito is also engineered with a fluorescent marker that permits effective monitoring of larvae to assess the effectiveness of control. The fluorescent marker is visible using a specialist microscope in all www.crs.gov i 7-5700 0

What Is HeinOnline?

HeinOnline is a subscription-based resource containing thousands of academic and legal journals from inception; complete coverage of government documents such as U.S. Statutes at Large, U.S. Code, Federal Register, Code of Federal Regulations, U.S. Reports, and much more. Documents are image-based, fully searchable PDFs with the authority of print combined with the accessibility of a user-friendly and powerful database. For more information, request a quote or trial for your organization below.



Short-term subscription options include 24 hours, 48 hours, or 1 week to HeinOnline.

Purchase Access

Already a HeinOnline Subscriber?

Log In

profiles profiles most