We are moving into the height of the flying and biting insect season in my part of the world. So I thought it would be a good time to bring up a topic I had questions about last fall: that is the role septic systems might play in the spread of the Zika virus. This is part of a larger question about what impacts failing or less-than-adequate systems have on human health.

During classes on septic system inspections, my colleagues and I talk in general terms about the importance of good systems that protect the environment and human health. There is always some discussion about the potential threat of a failing or poorly maintained septic system. And someone always points out that homeowners and others know enough to stay away from surfacing effluent and around sewage tanks. Our response, though lighthearted and hopefully somewhat humorous, is to point out the homeowner’s black Lab likes to find stinky things and roll in them. Afterward, Fido comes into the house to show his love and affection!

This generally leads to a more serious discussion about the fact that children can get into these areas and come in direct contact with the effluent. And since service providers wear the proper protective clothing while working on systems, shouldn’t they then consider any direct contact with wastewater a big problem?

VIRUS RISKS

Outside of direct contact though, there are other ways disease can be spread, the most concerning of which is through insects, primarily mosquitoes. It is not so much that the mosquitoes pick up disease from the effluent, but more that having wet areas and standing water create good breeding areas for mosquitoes. And then they subsequently pick up viruses like Zika or West Nile during their life cycle and transmit those viruses to humans when they bite us.

Where I live in the upper Midwest, we don’t have the Zika virus, but we do have West Nile virus, and while the incidence of West Nile disease are relatively low — a few cases a year — it is something to be aware of. Typically, West Nile virus spreads to humans and animals via infected mosquitoes. Mosquitoes become infected when they feed on infected birds. You can’t get infected from casual contact with an infected person or animal.

Most West Nile virus infections occur during warm weather when mosquitoes are active. The incubation period — the period between the bite by an infected mosquito and the appearance of signs and symptoms of the illness — ranges from two to 14 days.

West Nile virus has occurred in Africa, Asia, Europe and the Middle East. It appeared in the U.S. in 1999, and since then has been reported in every state except Hawaii and Alaska, as well as in Canada.

Information supplied from Mayo Clinic shows West Nile virus might have spread in other ways, including organ transplantation and blood transfusion. However, blood donors are screened for the virus, substantially reducing the risk of infection from blood transfusions. There have also been reports of possible transmission of the virus from mother to child during pregnancy or breast-feeding, or exposure to the virus in a lab, but these are rare and not conclusively confirmed.

The good news is that only about 1 percent of people infected become seriously ill beyond flu-like symptoms. The elderly and people with a condition like cancer that suppresses the immune system are most susceptible.

TIME TO REPAIR

The question posed was, can pesticides be used to control the mosquitoes around the failing septic systems? The easy answer to this is yes, but the ultimate solution is to repair or replace the system or parts of the system that are causing the condition.

Products on the market can be used to temporarily reduce mosquito breeding potential. Oils can be applied to the surface that suffocate the adult mosquitoes, and the pesticide methoprene — at very low concentrations — can be sprayed. Contact your local health department, agriculture department or mosquito control districts for the list of allowable pesticides in your area and to learn about required permits for their use.

The real solution is to fix or prevent the problem. Just like everything else we do as professionals, this involves educating the homeowners and the general public about the potential problem and how to fix it. Contractors and service providers are always in contact with the public, so this should be a part of our conversations to ensure system problems are determined and fixed.

As mosquito season approaches, homeowners should be encouraged to have a professional check seals on septic tanks and make sure risers are sound and watertight. If there is evidence of surfacing effluent, the system should be inspected, the causes determined and repairs or replacement scheduled. As a public service, you can suggest the homeowner walk their property once a week and check tarps or old tires for standing water, clean clogged gutters; basically address any identifiable areas where mosquitoes can breed.

As industry professionals, it is important that we highlight the many ways neglected septic systems can affect public health.