WHO has published a long, informative article: Mosquito control: can it stop Zika at source? Excerpt:
The possibility that a mosquito bite during pregnancy could be linked to severe birth defects in newborns has alarmed the public and astonished scientists. Detection of an upsurge in cases of microcephaly, associated in time and place with Zika virus circulation, has been accompanied by findings of additional congenital malformation of the brain, detected in fetuses (by ultrasound), stillbirths, and newborns, and evidence of damage to eyesight and hearing. For women of childbearing age living in or visiting affected countries, the prospect of giving birth to a baby with such severe defects is terrifying.
The association of virus circulation with an increased detection of Guillain-Barré syndrome adds to the concern. GBS is an autoimmune disorder with various causes, including infections with some viruses and bacteria, most commonly Campylobacter jejuni. To date, an association between Zika virus circulation and an increased incidence of GBS has been reported in 8 countries: French Polynesia, Brazil, El Salvador, the French territory of Martinique, Colombia, Suriname, the Bolivarian Republic of Venezuela, and Honduras. In some of these countries, the fact that Zika is the only circulating flavivirus adds weight to this presumed association.
Even in countries with advanced health systems, around 5% of patients with the syndrome die, despite immunotherapy. Many require treatment, including ventilatory support, in an intensive care unit, sometimes for months up to a year, adding to the burden on health services.
If these presumed associations are confirmed, the human and social consequences for the over 30 countries with recently detected Zika outbreaks will be staggering.
In the large outbreaks that affected some Pacific island nations, first in 2007 and again in 2013-2014, and then spread to the Americas, Zika virus has frequently co-circulated with dengue and chikungunya viruses. These viruses cross-react in diagnostic tests, making test results unreliable and putting better tests at the top of the list of most-needed new medical tools.
Moreover the currently available PCR test can detect infection only during the period of illness when the virus is replicating, a weakness further compounded by the fact that 80% of infections cause no symptoms. Although at least 15 groups are working on Zika vaccines, WHO estimates that it will be at least 18 months before vaccines could be tested in large-scale trials.
For all these reasons, WHO recommends stepped-up personal and population-wide measures for mosquito control as the best immediate line of defense.
