The Fog of Fogging

by Patrick Martin, MD,

Why is the Ministry of Health not fogging like before?    Invariably, this lamentation erupts when mosquito-borne infections reach epidemic proportions.  It happens every 4 to 6 years when dengue occurs.  It happened in 2014 when Chikungunya left many bed-ridden.  Now, it is the milder Zika.  On the horizon is Mayaro.

To many, fogging is visible evidence that the Ministry of Health is doing something about Zika.  The sights and sounds of a fogging truck regularly making its rounds in our communities were seared into our childhood memories.  Flashbacks are evoked by television images of fogging in outbreak areas around the world.  If they have to fog in Florida, shouldn’t it be done in St. Kitts and Nevis?

The fact is that the Federation has open borders.  Every new or re-emerging infection in the world and this hemisphere will affect our population.  It is not a matter of if but when.  In other words, all new infections are imported.  What matters most is to build the strongest possible level of psychological and physical preparedness and response.  In so doing, all actions should be rooted in the science and art of public health and risk communication.

The Ministry of Health has a duty of care to the public.  It is that all chemicals and other technologies used for the purposes of health care must be of assured effectiveness while minimizing adverse reactions to humans and the environment.  There is a benefit and a risk to every chemical substance.  An example of risk is the irrational use of chemicals which leads to resistance.  Many species of pathogenic bacteria are now immune to the once all-conquering penicillin and other antibiotics.  Mosquitoes display similar versatility.

Fogging has its place but only under specific conditions.  The adult Aedes mosquito is active from dawn to dusk and breeds in and around households, not swamps.  This best time to fog is during the day and when the wind is calm.  Therein lies the challenge.  Windows and doors are closed during the day because people are at work.  Spraying when it is gusty causes the fog to be “gone in the wind”.  Even if the fog penetrates a house or yard, it has zero effect on the 3000 eggs laid by the adult female and the hatched wrigglers.

A chemical approach alone to mosquito control is a losing proposition.  The singularly most effective tactic is source elimination.  To reduce or eliminate the burden of Aedes mosquitoes is to attack breeding sites in a military-style “search and destroy” mode.  Breeding sites abound in the homes and yards of mosquito farmers who are our friends, family and neighbours with pots, pans, drums and other receptacles strewn all over their private property.  After the female Aedes sucks a blood meal, all she needs to lay her eggs is a damp spot or a drop of water.

In Public Health, the subject area called Vector Control has catapulted to the front burner. Disease vectors such as the Aedes species are formidable foes.  Aedes has the capacity to carry the Yellow Fever virus, the four Dengue viruses, and the viruses that cause Chikungunya, Zika and the emerging Mayaro disease.  These viruses cause human illness and visitor cancellations.  Outbreaks and epidemics are health and economic issues, simultaneously.

The Federation’s health is its wealth.  Health is too big to fail.  This is why in the fog of budgeting, Public Health must be alongside National Security and Tourism at the allocations trough which is zealously controlled by the Ministry of Finance.

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