The type of eye problems in babies born with Zika-related microcephaly is more extensive than originally thought, according to findings from three Brazilian babies who were born at the end of 2015.
In other Zika developments, Consumer Reports recently put insect repellents to the test, noting the ones that performed well against Aedes mosquitoes, which can transmit the virus, and warning that some plant-based products performed poorly, especially against that species.
Eye problems and microcephaly
The three babies—all boys—were born to mothers who had suspected Zika infections in their first pregnancy trimesters. Researchers from Brazil and Stanford University published their findings from the infants' eye exams today in an early online edition of Ophthalmology.
An earlier report on 27 Brazilian babies born with Zika-related birth defects detailed a constellation of eye problems, which is reflected in current guidelines for clinical work-up and management of affected infants.
However, today's report details three more eye problems: retinal lesions, retinal bleeding, and abnormal retinal blood supply. Some of the conditions could impair vision if left untreated, the team warned.
In addition, the babies also had eye problems identified in the earlier report, including pigmentary maculopathy and chorioretinal atrophy.
Though the number of patients in today's report is small, the findings add to a growing body of clinical information about the impact of Zika virus on children's eye development and vision, the researchers concluded. They added that it's still not clear if there's a direct connection between Zika virus and the eye problems or if they're a complication of microcephaly.
Darius Moshfeghi, MD, senior author and ophthalmology professor at Stanford, said in an American Academy of Ophthalmology (AAO) press release today that it's important to identify the cause of the eye problems to better determine which babies will need screening.
How insect repellents stack up
The new comparison of insect repellents from Consumer Reports found that products with three active ingredients—DEET, oil of lemon eucalyptus, and picaridin—performed well on tests against Aedes and Culex mosquitoes and deer ticks. Some products marketed as "natural," however, offered little protection, especially against Aedes mosquitoes.
To compare the products, testers placed their arms in cages with disease-free female mosquitoes and watched and recorded bites for 5 minutes every hour. To measure performance against ticks, the disease-free bugs were released on untreated skin and were watched to see if they crossed over to treated skin.
In coming up with their list of recommended products, Consumer Reports urged people to read insect repellent labels closely, taking into account not only the active ingredients, but also their concentrations. In some instances, the concentration had effectiveness and safety implications.
The investigators noted that products containing 15% to 30% DEET provide long-lasting protection against mosquitoes and ticks, but excessive concentrations can pose risks such as rashes and disorientation. Tests revealed that products that contained only 7% DEET didn't work well, especially against Aedes mosquitoes, the type that can spread Zika virus and other diseases.
A product containing 20% picaridin was Consumer Reports' top overall repellent, but one containing only 5% of the ingredient scored much lower, underscoring the advice to closely read the labels.
Oil of lemon eucalyptus was the only naturally occurring compound to do well in tests, repelling mosquitoes and ticks for at least 7 hours. Other plant-oil–based products, though, such as those containing cedar, citronella, lemongrass, or rosemary, provided little protection, often failing within 30 minutes, especially against Aedes mosquitoes.
The US Centers for Disease Control and Prevention in its Zika-prevention advice recommends that people, especially pregnant women, use insect repellents that are registered with the Environmental Protection Agency (EPA) as directed on the product labels.
Other developments
- Conspiracy theories and pseudoscience claims about Zika virus vaccines could have a lasting effect on peoples' healthcare decisions, US-based researchers reported May 20 in Vaccine. Uncertainty about the source and effects of the virus are fueling the misinformation, the team found, based on their real-time Twitter monitoring. For example, one claim was that microcephaly is caused by the MMR vaccine and that drug companies are blaming Zika in order to sell Zika vaccines. The authors urged authorities to address people's concerns and debunk the claims.
- Brazil's ministry of health yesterday reported 89 more suspected microcephaly cases, according to a statement translated and posted by Avian Flu Diary, an infectious disease news blog. Of cases still under investigation, officials ruled out 114 and confirmed 50, putting the number of suspected cases still under investigation at 3,257 and the confirmed total at 1,434.
- The US House of Representatives yesterday passed a bill along party lines to relax EPA permit requirements for approved pesticides to be used in navigable waters, the New Orleans Times-Picayune reported. Republican lawmakers said the permit requirement makes it harder for local governments to battle Zika-carrying mosquitoes, but the White House disputes that the process makes it harder to spray for mosquitoes and said Republicans rebranded the legislation to skirt Clean Water Act protections.
See also:
May 24 Ophthalmology abstract
May 25 AAO press release
May Consumer Reports insect repellent buying guide
EPA-registered insect repellent search tool
