Daily news reports have sounded the alarm that infection of pregnant women with Zika virus has been linked to microcephaly in their infants. Microcephaly is a birth defect in which infants are born with undersized skulls and brains. On Monday, February 1, 2016, the World Health Organization declared the Zika virus and its potential link to microcephaly an international public health emergency.
HOW DOES ZIKA VIRUS SPREAD?
Zika virus is known to spread by mosquitos in Brazil and many other countries and territories in Latin America and the Caribbean. The Centers for Disease Control (“CDC”) has advised pregnant women to avoid travel to affected countries. Adding to the alarm is the report, yesterday, that a patient was infected with Zika after having sex with someone who had returned from Venezuela. In breaking news, the CDC now cautions pregnant women to avoid contact with semen from men recently exposed to the virus. If Zika is spread by mosquitos and sex, what are the prospects for transmission by other means? In particular, can Zika be spread by bed bugs?
Currently there is no definitive answer to whether Zika may be spread by bed bugs. However, given the horrendous potential consequences of such a route of transmission, consideration should be given to the following scenario.
A person is infected with Zika. While the virus is present in his blood, a bed bug obtains an infected blood meal. The Zika virus survives in the bed bug gut. This bed bug then feeds on its next victim, and while feeding, deposits feces on the host’s abraded skin or mucous membrane. The virus from the feces enters the host. The host happens to be pregnant. Is this woman at risk for having a baby with microcephaly?
Consider that the absence of proof is not proof of safety. For Zika not to be transmitted, the following factors would have to be present:
- Bed bugs have no opportunity to obtain a Zika-infected blood meal.
- Zika dies in the bed bug gut.
- Zika does not appear in bed bug feces.
- Zika virus in bed bug feces cannot enter through broken skin or mucous membranes.
It is far from certain that these factors align in such a fashion to rule out Zika spread by bed bugs.
WHAT HAPPENS WHEN BED BUGS FEED ON ZIKA VIRUS?
It is obvious that bed bugs will have the opportunity to feed on persons infected with Zika. Moreover, other blood-borne pathogens have been detected in the bed bug gut. Studies have shown that hepatitis B and Trypanosoma cruzi (the parasite responsible for Chagas disease) are present in the feces of bed bugs infected with such pathogens. It would appear that the potential exists for bed bugs to be vectors for Zika by excreting Zika-laden feces onto human skin. If it reaches this point, the virus can then enter through abraded skin (from earlier lesions) or mucous membranes.
A reasonable conclusion is that there is no sound reason for assuming that there is no possibility of Zika virus transmission by bed bugs. Given the extremely high stakes, there is a crucial need for research to determine whether Zika can be transmitted by bed bugs. Unless and until well-designed studies establish that bed bugs cannot pass Zika in its feces, it would appear that appropriate precautions should be taken.