Collaborations continue with SpringStar as Jaydon Bailey, Rebecca Heinig, and Geoffrey Kemble visit to work with the Center’s team toward improving the design of the pyriproxyfen autodissemination system. Using 3D printers and precise measurements, the group is moving closer to resolving issues that will maximize pyriproxyfen application onto gravid female mosquitoes seeking to lay eggs. Attractive water sources within the devices are not available for egg-laying, and the egg-laden females leave and get painted with the juvenile hormone inhibitor which will be deposited where the eggs are eventually laid. While the eggs do hatch and develop eventually into pupa, that’s as far as their development goes. They never become adults. By exploiting female behavior, such devices are prime for controlling areas where hidden habitats occur and more traditional control techniques are less effective.
Randy Gaugler & Ary Faraji
Center for Vector Biology – Rutgers University / NJAES
Zika virus is not a new disease. Zika virus has been largely confined to equatorial Africa in the tropics where it circulated predominately between forest dwelling mosquitoes and wild primates. The virus was actually discovered from a sentinel monkey that had been placed in a cage in the Zika forest of Uganda in 1947. But the virus rarely spilled over into human populations even in highly endemic areas of Africa. The explosive reemergence we are current witnessing is truly extraordinary. Human activities are the greatest factor attributing to this spread because of rapid changes in land use and globalization leading to rapid increases in the movement of goods and people.
Zika is a pandemic because the virus is no longer confined to Africa but has spread to Asia, the Pacific Islands, and now the Americas where the World Health Organization is predicting several million infections and classifying Zika a ‘global health emergency’. The virus is not continent-hopping via the spread of mosquitoes, but because of the frequency and rapidity of air travel by humans. An individual can be bitten by an infected mosquito where the virus is circulating, and then fly long distances within a short span of time. Since the incubation period in humans usually lasts several days, if that infected individual is bitten by a local mosquito that can replicate and transmit the virus (i.e. vector competency in the host mosquito), then local infections in a new area may occur. However, only a handful of Aedes mosquitoes are vector competent for Zika virus. The primary vector is the yellow fever mosquito, Aedes aegypti; a highly invasive urban species. Their eggs may remain dormant for months in small containers, which contribute to a wide geographical distribution. Not coincidentally, these mosquitoes are abundant in the areas where Zika virus is currently circulating in the Americas. In short, humans are responsible for the transportation of Zika virus, whereas mosquitoes are responsible for transmission of the virus to humans.
What is New Jersey’s vulnerability to Zika virus? The answer is unclear at present. In the U.S., Aedes aegypti is a tropical species reported along the Gulf Coast, Florida and parts of California. Amazingly this species was just reported to be established in a Capitol Hill neighborhood in Washington DC, where it likely overwinters below ground where temperatures remain above freezing. New Jersey does not have established populations of Aedes aegypti, but the Asian tiger mosquito, Aedes albopictus is a resident. This mosquito has been shown to carry the Zika virus and is highly suspect as a vector in some locations. Aedes albopictus, like Aedes aegypti, is an invasive species that prefers small water-holding containers (tires, pots, bird baths, gutters, etc.) in close proximity to people in urban centers and preferentially feeds on humans.
Unfortunately, mosquitoes are not the sole means of Zika virus transmission. As with any blood-borne pathogen, transmission through contaminated blood is a serious possibility. The infectious phase of the virus is usually only a few days, but may last longer in some individuals. Consequently, many blood collection agencies are already screening donors to assure they have not traveled from an outbreak area within the previous month. An additional concern is sexual transmission, presumably due to survival of the virus in semen. A case of Zika virus transmission in the U.S. was recently reported in Dallas where an individual became infected after having sex with someone returning from South America. The prevalence of sexual transmission is as yet unknown, but we can be certain that this will greatly complicate efforts to contain outbreaks. Condoms are recommended for men returning from Zika endemic areas.
The good news is that four out of five persons infected with the virus show no symptoms. When the disease is symptomatic it tends to be mild and characterized by fever, rash, joint pain, and conjunctivitis (red eyes). Severe disease may require hospitalization but this is uncommon and death is rare. The bad news, of course, is the potential link between infected pregnant women and birth defects in their infants. Brazil has reported a 20-fold increase in microcephaly (reduced brain size) in newborns and has attributed this to Zika virus. Although not scientifically proven, circumstantial evidence strongly implicates the virus, and authorities are urging women in outbreak areas to delay pregnancy. The U.S. Centers for Disease Control and Prevention is recommending special precautions to pregnant women to postpone travel to areas with Zika virus activity or to take extra steps for the prevention of mosquito bites if travel is unavoidable. If microcephaly were not enough, the virus had earlier been implicated with another neurological disease, Guillain-Barre syndrome, in which the immune system attacks peripheral nerves. Studies are underway to examine these associations, albeit researchers are hampered by the lack of a good non-primate model.
It is worth noting here that ultrasound can detect microcephaly. The ultrasound test should be conducted late in the second trimester or early in the third trimester.
Vaccines for Zika virus are currently under development, but will not be available (if ever) for human use for many months if not years. Most mosquito-borne viruses do not have a vaccine or preventative medication available. The best prevention is the avoidance of mosquito bites. If travel to epidemic areas is not avoidable, travelers should take extra protection from mosquito bites by wearing long sleeve shirts and pants, staying indoors with air conditioning when mosquitoes are most active, and using a DEET-based mosquito repellent.
What is New Jersey’s response to the outbreak? There is concern among state, county and university public health workers but not alarm. The closely related chikungunya virus ran amok in the Caribbean last year, but this did not translate into significant outbreaks in the U.S. where window screens, air conditioning, and local mosquito control agencies are prevalent. If outbreaks of Zika virus should occur in New Jersey they are likely to be limited. In the event of an outbreak, suppressing vector populations is the only effective means of reducing disease transmission. The control of the most probably New Jersey vector, the Asian tiger mosquito, is difficult because this species thrives in residential backyards where access is difficult and habitats are scattered. New Jersey’s authorities are currently making plans to incorporate Zika virus into the current arboviral surveillance and to respond aggressively to suspected cases with intensive targeted mosquito control in those localities.
Assistant Professor – Microbiology/Virology: Applications for a tenure-track assistant professor position in the Rutgers University Department of Entomology/Center for Vector Biology are invited. The position will be 70% research and 30% teaching with a joint appointment in the Entomology and Microbiology Departments. The successful applicant will develop a nationally and internationally recognized program focusing on the biology, ecology and epidemiology of emerging arthropod-borne diseases to reduce their public health impact. Rutgers is a major research university, and competition for funds from external sources such as the state of New Jersey, NIH, Gates Foundation, CDC, USDA, NSF, and EPA is expected. The successful candidate will interact closely with faculty in the Center for Vector Biology, Entomology Department and Microbiology Departments as well as multidisciplinary working groups in other centers and departments at Rutgers University with a shared interest in emerging infectious disease, climate change, surveillance, host-pathogen coevolution, vector management, diagnostics, risk modeling, and bioterrorism issues. The successful candidate will also be expected to take a leadership role in interactions with the core public health functions of the medical school and the New Jersey Department of Health, as well as communicate with key stakeholder groups as needed. The successful applicant will teach and contribute to teaching graduate and undergraduate courses, particularly infectious disease topics which enhance cooperation with the medical school (e.g., arbovirology, epidemiology, pathogen ecology) and direct undergraduate and graduate students as well as post-doctoral fellows. Participation in departmental and University committees and assistance in undergraduate and graduate curriculum development is expected.
SALARY AND BENEFITS: Academic Rank: Assistant Professor (10 month, tenure track). Salary is highly competitive and commensurate with education and experience. Excellent personal benefits package is provided, including one month of annual leave per year, health insurance, life insurance, retirement program, and other institutional benefits.
EDUCATION AND EXPERIENCE: Candidates must have a Ph.D. in entomology, microbiology or related area from an accredited institution. Excellent communication, interpersonal skills are desired. Knowledge of arbovirology, epidemiology, pathogen ecology desired.
Application Procedure: Applications will be accepted until April 15, 2016. Send your letter of application, curriculum vitae, personal statement and the names and addresses of four references electronically or by mail to: Randy Gaugler, Distinguished Professor & Director Center for Vector Biology, 180 Jones Ave, Rutgers University, New Brunswick, NJ 08901-8536 USA (firstname.lastname@example.org)
Dr. Devi Suman won the $1000 John L McColgan Grant from the Northeastern Mosquito Control Association for the development of a non-lethal mosquito ovitrap. This affordable trap can add to a mosquito control agency’s ability to monitor mosquito population levels of mosquitoes, particularly container mosquitoes such as Aedes albopictus or Ae. aegypti. This lightweight trap does not require a light source and attracts not only female mosquitoes searching for a suitable place to lay eggs, but the eggs as well. Male mosquitoes will also come to the trap. Specimens are caught inside and maintained in good condition to allow molecular studies. Eggs can develop into larvae depending on how often traps are sampled. Thus, this trap can sample all aspects of population structure, is easy to use and is biodegradable.
From Alexandra Villiard’s doctoral work: Villiard A and R Gaugler. 2015 Long-term effects of carbohydrate availability on mating success of newly eclosed Aedes albopictus (Diptera: Culicidae) males. Journal of Medical Entomology, 52(3): 308-314, DOI: http://dx.doi.org/10.1093/jme/tjv030
“Sugar availability varies greatly in nature, and determining how this affects male mosquito fitness is essential for understanding population dynamics. We allowed male Aedes albopictus (Skuse) carbohydrate access for increasing intervals of time immediately after eclosion and we evaluated their fitness by comparing mortality, mating success, and sperm transfer. We compared individual male Ae. albopictus, which were offered water or 20% sucrose solution for 24, 48, or 72 h. As predicted, there were significant increases in fitness for each additional day of sucrose access. Following sugar exposure, we allowed males daily access to three virgin females. We assessed mating success through observation of spermatozoa in the female spermathecae. When individuals of the same age were compared, males with sugar access exhibited significantly greater mating success than water-treated males in all treatments. The total number of spermathecae filled by males with sugar access in the 48- and 72-h treatments was also significantly greater on some days; these were 3–5 d posteclosion in the 48-h treatment and 5–6 d posteclosion in the 72-h treatment. We conclude that extended sugar access at eclosion is important for maximizing fitness in male Ae. albopictus and should be applicable to sterile male release efforts, especially when laboratory-reared males suffered from other disadvantages. We recommend retaining adult males for 3 d posteclosion prior to release to improve their mating success in male release initiatives.”
Congratulations to Scott Crans for finishing his MS on “Spinosad: Efficacy and persistence against container-inhabiting mosquitoes” under Dr. Robson and to Alexandra Villiard for finishing her Ph.D. on “The influence of carbohydrate requirements on Asian tiger mosquito behavior and fitness” under Dr. Gaugler. It is always an accomplishment to finish the work and kudos on their graduation!
Drones or UAVs (unmanned aerial vehicles) represent the potential for targeting precise pesticide application to specific areas, reducing exposure to non-targeted areas and overall pesticide use. Dr. Randy Gaugler is heading a project for the use of UAVs for more precise pest control. These areas, often in large swamp or saltmarsh topographies, can represent significant costs to mosquito control programs when traditional methods of application are used, including aircraft and pilots. But UAVs can potentially eliminate much of that cost. Dr. Gaugler says “…when Greg Williams brought multi-rotors to my attention, particularly their ability to fly autonomous missions, I saw the potential for precision mosquito control. Small, agile, inexpensive, fully autonomous, easy to program missions, low maintenance—what was not to like?”
Dr. Greg Williams is the Superintendent of the Hudson Mosquito Control agency and a CVB member. He is responsible for designing and constructing the UAVs, along with help from other Center members, including Scott Crans, Ary Faraji, Devi Suman, Ishik Unlu and Yi Wang. The project’s critical mission is to target specific areas with application technology to reduce the environmental impact as well as time and dollars involved. This technology includes a carbon fiber 850 mm hexacopter with an underwater camera for surveying mosquito larval populations, the ability to dispense liquid or briquette pesticides and the use of GPS systems to determine and record flight patterns. Flights can be autonomous through a 3DR Pixhawk autopilot. This allows mosquito control agencies more flexibility and ease of use with the UAVs with a shallower learning curve.