When I saw the news about the Utah caregiver contracting Zika far from any mosquitoes, I thought: “haven’t we been here before?”
We have. Remember Ebola? It was thought to be only transmitted with difficulty, from direct blood contact. Then we realized, too late, that bloody droplets were infectious as well. Caregivers went from surgical masks to separate breathing systems and the spread finally slowed.
In Utah, a caregiver came down with Zika virus. It’s a mystery, but one with only a few possible conclusions.
- The caregiver did have sexual relations with her dying charge. While this is possible, it is unlikely.
- A mosquito, carried by the man in his luggage, found a way to get into a stagnant water source with sufficient nutrients to carry it through the larval stage. It then grew to adulthood in the Utah house, biting the caregiver and infecting her. While this is possible, it is extremely unlikely.
- Another vector, a tick or a flea, drank the patient’s blood and then later bit the caregiver, transferring the infection to her. While this is possible, it would involve a previously unknown carrier of Zika virus.
- Zika virus is spread by bloody droplets, particularly in individuals who have a very high viral count, as this sick man did. During the process of caring intimately for him, the caregiver was exposed to a bloody droplet that reached a mucus membrane (eyes, nose, or mouth) and infected her. We know that Zika is spread by blood, and I’m not sure why this wouldn’t be the most likely scenario.
- Zika virus is spread by saliva or urine in individuals. We know that both saliva and urine contain the virus, but we aren’t sure if they are infectious. In an individual with a very high viral count, it is possible – if very alarming – that he infected his caregiver with either of those secretions.
In my book, The Bare Essentials of Zika Virus, I note that we’ve had documented blood transmission of Zika for nearly a decade. I also point out that the focus on how mosquitoes spread the illness ignores the reality that humans are the most likely to spread Zika to a new region. I also point out that serious and severe side effects (microcephaly, guillain-barré) are much more likely to be autoimmune cross-reactions rather than Zika alone.