The mosquito master speaks: It’s not Zika, it’s mosquitoes

The mosquito master speaks: It’s not Zika, it’s mosquitoes

Raymond Ramcharitar
Published: Guardian
Wednesday, February 10, 2016

Prof Dave Chadee believes the emphasis should be on targeted source reduction: dealing with any receptacle or area which could contain the still water necessary for the mosquito to breed.
“How could you declare a national emergency for Zika when we have no cases of the virus in Trinidad?” asked UWI Professor Dave Chadee, one of the world’s foremost experts on mosquito borne diseases and the Aedes aegypti mosquito.

“That is an epidemiological problem and we really do need to sort out the situation with respect to hard evidence. If the virus is not present you cannot say there is a national emergency.”

Prof Chadee was the Anthony N Sabga Caribbean Awards for Excellence (joint) laureate in Science & Technology in 2013. This was his response of the declaration of a national emergency by Minister of Health, Terrence Deyalsingh, in the wake of the World Health Organization’s (WHO) declaration of the Zika as a Public Health Emergency of International Concern.

Though the effects of the Zika virus are relatively mild, what has caused the mounting concern is its association with microcephaly, a condition whereby newborn babies of infected mothers have unusually small heads. The WHO release stressed that it “strongly suspected” a causal relationship between Zika and pregnant women and congenital and neurological problems. However, its release continued, there is as yet no scientific evidence to support the suspicion.

This was Chadee’s thinking, and refers approvingly to another UWI academic, Noel Kallicharan, whose letter was published in a newspaper last week, which said, among other things, that only six of the 270 confirmed cases of pregnant women who gave birth to microcephalic babies in had tested positive for the Zika virus.

However, if Zika is not quite the plague it’s being made out to be, there are other reasons to worry about mosquito issues in Trinidad and the region.

“What is really required,” continued Chadee, “is a decision being made about whether you’re talking about the virus, the risk of the disease coming to Trinidad, or is it a mosquito emergency. There is clearly a mosquito problem, and since there is no vaccine, the threat must be the mosquito Aedes aegypti.”

This mosquito is also responsible for the transmission of dengue and chikungunya, which are endemic in Trinidad & Tobago. Much of Chadee’s research has been directed at this mosquito.

As it happens, the timing is on the side of public health authorities. Although, said Chadee, mosquito densities in Trinidad & Tobago are unusually high, as we enter the dry season, those densities are set to decline sharply, by as much as 50 to 60 per cent, because of the simple drying up of the breeding sites. 

What the emphasis should be on now, he said, is targeted source reduction: dealing with any receptacle or area which could contain the still water necessary for the mosquito to breed.

“There must be a health education component. I’ve not seen that apart from the information on the news, which tells about the mosquito and the virus and how they’re transmitted,” he said.

The overarching problem, said Chadee, has nothing to do with the disease per se, but with the management of the Vector Control unit of the Ministry of Health. Chadee worked for a number of years in this unit before moving to academia.

“A lot of people in Vector Control know about this, and they should form part of the strategy of the ministry. This year marks 40 years since Vector Control has been given a mandate to reduce or eliminate vector densities, but it has not been done.” The reason, he said, is that “only in times of crisis are resources thrown at Vector Control, but it’s not done consistently.”

There is also the problem of changing proven strategies of mosquito control for new, seemingly ineffective strategies. An example is the WHO technique for reduction of mosquito populations by the introduction of a chemical, temephos, to water sources. This has been changed since last year. Now a product is used to create a thin film over water surfaces to prevent the larvae from breathing, But this can be dissipated by a single rainfall, whereas a treatment of temephos lasted four weeks.

Chadee’s advice to the public would be as follows:
1 Take action in and around their homes, and try and remove all the containers that are liable to breed mosquitoes
2 People who have to store water can put temephos which is WHO recommended
3 Cover water collectors, like drums or barrels and empty cans from the immediate living area
4 Focus spraying efforts on the bedroom, since this is where mosquitoes are most likely to be. Walls should be sprayed, since it is there the mosquitoes sit before and after taking a meal from the host. Air conditioning units also help, but the temperature must be below 24 degrees
5 Use creams with Deet, which can be put on the skin to prevent bites.

These strategies will help the average person, but the government’s strategy should be coordinated to control source reduction on a larger scale. Source control is especially important as Chadee’s latest research (in a paper published in the journal Acta Tropica last year) suggests the mosquito problem is evolving.

“Previously,” he says, “the breeding habitats of Aedes aegypti were relatively clean water. However, they’re adapting to the environment and, they’re going where they weren’t before, including sewers, pit latrines, and septic tanks.”

His research has also revealed that mosquitoes can emerge copulate and blood feed in total darkness. In that situation the life cycle is reduced by a couple of days. But if the mosquitoes go to underground environments, their life cycle gets faster.

More worryingly, in the wild, he discovered that mosquitoes were living more than 100 days, as opposed to the 30 days they are believed to survive. This raises a whole new set of problems, since a mosquito which survives 90 days will produce eggs and mosquitoes who are born transmitters.  They will not have to feed off an infected person to acquire the virus to transmit.

To address these breeding and mosquito population control issues, Chadee is one of the pioneers of sterile male technique—where male mosquitoes are sterilised using radiation and released into the wild. He is going to China later this year to work on the sterilisation techniques, and has done work in Mauritius, Reunion and St Vincent.

Unfortunately, said Chadee, he has not been used or consulted by the government of Trinidad & Tobago, despite it being UWI’s mandate to provide this sort of support to regional governments.
“We are here and ready to help when asked,” he says.

INFO
A public lecture on mosquito borne disease given by Chadee in 2014, hosted by the ANSA Caribbean Awards and the City Corporation of San Fernando, is available for viewing on the Caribbean Awards YouTube channel, www.youtube.com/user/ANSCAFE. So is Prof Chadee’s biography and a studio interview from 2013.

obviously... as  the way the system behaves... there is something horrific actually goin' on..or planned to go on for the people... that all this noise about Zika is to hide and cover for.

we shud be paying 24/7 attention to the MoG, Bill gates, of the illuminati/Bilderberger Department of Genocide to try ferret out what's up. we shud be monitoring his every move, phone call, letter and note, email....all his communications.  he may be up to something huge in the world

{ GMoG...Global Minister of Genocide }