Anti-mosquito teams target dengue pest

CDC confirms first local dengue fever cases

Mosquito extermination teams are
reporting a marked drop in the number of mosquitoes capable of spreading dengue
fever after a concerted campaign.

The intensified efforts by the
Mosquito Research and Control Unit since January have been in response to three
suspected dengue fever cases, which were confirmed by the Centres for Disease
Control and Prevention last week.

No new cases have been reported
since three people from West Bay and George Town contracted dengue in January,
according to local public health officials.

Bill Petrie, director of the
mosquito control unit, said his teams had intensified their efforts in January
when the dengue cases were first suspected.

 “We took all the work crews who work on this
end and intensified all our efforts in those areas. Then we expanded it
outwards from those locations. That took about two weeks,” Mr. Petrie said.

Dengue fever is caused by a virus
transmitted to humans by the bite of an infected mosquito.

The unit has been targeting
specific problem areas rather than blanketing the entire island, an approach
which Mr. Petrie said was paying dividends. “It looks like we have some good
results in that we seem to be reducing the numbers of the aedes aegypti mosquitoes,” he said.

He explained that this type of
mosquito, which is also capable of spreading yellow fever, is different from
others as its primary food source is human blood so it lives around people, in
yards and gardens by their homes, and is active throughout the day and not just
at dawn and dusk like other mosquitoes.

“They only really live around
humans. That is why they are so efficient as disease carriers. They usually
only feed on human blood, it’s their favourite blood source. Also, it doesn’t
fly very far, it doesn’t have to,” he said.

January’s cases are the first local
cases reported in Cayman. Previous cases of the fever seen in Cayman have been

“We are glad to say that those
three persons had recovered by late January, and equally glad to say there are
no more suspected dengue cases in the Cayman Islands,” said the Medical Officer
of Health, Dr. Kiran Kumar.

The CDC confirmed the three
patients had dengue type 2, the most prevalent strain of the virus.

Dr. Kumar said the local cases were
likely caused when visitors from countries with dengue, or residents returning
home from abroad, contracted mild, undiagnosed cases of the illness, who were
then bitten by mosquitoes that transferred it to the three victims.

Blood samples had been sent in
January from Cayman to the Caribbean Epidemiology Centre in Trinidad, and then
passed on to the CDC in Puerto Rico to confirm the findings.

The results of these samples had
been expected in early February, but were delayed because the CDC lab was busy
dealing with an outbreak of dengue fever in Puerto Rico, Dr. Kumar said.

Public and private health
practitioners are monitoring for dengue cases. “If we encounter a suspected
case, we again will send samples to CAREC for testing,” Dr. Kumar said.

Health officials and mosquito
control staff encourage the public to examine their gardens, patios and yards
for places where standing water settles, as mosquito larvae grows in water,
often in buckets, or abandoned rubber tyres, or plant saucers.

“We keep on saying over and over
again to remove standing water from your yard, I know we sound like a broken
record, but it’s valid and it’s useful. You might have a beautiful, clean and
tidy garden, but it might just be one bucket that is the source. Just turn it
upside down,” he said.

He also advised removing garbage
and any other receptacles that may hold standing water from yards.

Mr. Petrie explained that aerial spraying
is not very effective in dealing with the aedes
mosquito. Instead, staff visit locations where mosquitoes breed and
use larvicide to kill larvae and take egg samples to establish what kinds of
mosquitoes are breeding in an area.

Dengue symptoms include high fever;
severe headache; backache; joint and eye pain; nausea and vomiting; and rash.
Most people recover without any complications, using pain relievers and bed

Dr. Kumar said that once a patient
has developed a fever, the infectious period lasts for only one week.

For more advice on
mosquito control, contact the Mosquito Research and Control Unit on 949-2557 in
Grand Cayman, or 948-2223 on Cayman Brac; and the Department of Environmental
Health on 949-6696 in Grand Cayman, or 948-2321 in Cayman Brac.


Dengue is spread by the aedes aegypti mosquito.
Photo: File