Fighting Zika — at any cost?



mozzie killer
mozzie killer


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Elsewhere in the world, precautionary measures were introduced after a discussion of the negative effects on health and environment that Zika could have. As of yet, there has not been a similar debate in Singapore.

As of 23rd September, there have been 387 Zika infections confirmed by the National Environment Agency, including 16 pregnant women.

pgp-zika
Insecticide being sprayed into the sewer at PGPR.

In contrast to dengue and chikungunya, Zika is quite new: before 2007, only fourteen people were infected. Then, the first big outbreak occurred on the Yap Islands, infecting 73 per cent of approximately 6,000 residents (excluding infants). However, none of them needed hospitalisation.

The central reason Zika is hard to deal with is that 80 per cent of the infected have little to no symptoms, turning them into silent carriers. It is then easy for it to spread throughout Singapore, a country both small in size and densely-populated.

Zika has negative consequences beyond health: people avoid crowds and businesses are hit. Several countries have put up travel alerts to Singapore, which may have been especially harmful to major events such as the Formula One Night Race. The government has started a mosquito wipeout campaign, destroying stagnant water where they can breed and fogging public places with insecticide. Some news sources have stated that this is costing the government $1 million a day. In addition, there has been an increased usage of repellent and insecticides by citizens to the point that FairPrice urged customers not to hoard.

mozzie-killer
Pumping mosquito-killing mist over large areas on the ground.

Of the many articles on Zika, none of them that I’ve come across express any concerns over the large usage of insecticides — be it ecological or on human beings. This raises concerns not just for how indigenous insects could be affected, but for our drinking water as well.

In contrast, a campaign to spray insecticide from the sky in South Carolina initially caused a public outcry. Beekeepers filmed colonies being wiped out. An owner of a farm said that it looked ‘like it’s been nuked’, with an estimated 2.5 million bees killed. The campaign was delayed for 24 hours while the legislature publicly weighed the pros (effective at stopping Zika) and cons (public health and environmental costs) of the proposed measures before finally greenlighting it.

However, this is far from new: similar problems should have arisen when fighting dengue and a research paper from 2011 noted the presence of 13 “emerging organic contaminants”, possibly from sewer lines, in the Marina Catchment.

In addition, Zika itself may be overblown. A recent study by the New England Complex Systems Institute (NECSI) noted the number of “missing cases” and found that of 616 mothers in Columbia infected by Zika in their third trimester, exactly zero had birth defects. This suggests that Zika is not dangerous in the late stages of the pregnancy.

NECSI suggests that in Brazil, the anti-Zika prevention measures themselves caused the birth defects! They point the finger at a pesticide that had been put in drinking water to kill mosquito larvae. However, nothing is known for certain until more research is done.

The biggest concern is that pregnant women get infected and thereby threatening the health of unborn babies. Considering Singapore’s efforts to increase birthrate, the Aedes mosquito is even more unwelcome here. People are concerned; some pregnant women walk around in winter coats, stop working or use multiple types of repellent.

While Zika is damaging to the health of unborn children, so are insecticides and the consequences of both are little known. Singapore is fairly small, and sprayed insecticide is likely to be spread to surrounding areas and nature resorts, which may affect our ecosystem in as-of-yet unknown ways.

Right now, effective countermeasures we can take are to be vigilant about culling mosquito breeding grounds (see here for NEA’s guidebook on Prevention of Mosquito Breeding), as well as to consistently use mosquito repellents to prevent mosquito bites. We won’t only be protecting ourselves, but the larger community as well. I sincerely hope that this won’t be the last article addressing the possible dangers of unconcerned insecticide spraying and that the government will also help to spread public awareness of the issue.

For more, visit Patrick Brugger’s blog


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