WHY PERSONAL PROTECTION IS SO IMPORTANT?
Personal protection is very important because of the deadly nature of
the diseases that biting-insects carry. Personal protection in the form
of repellents and insecticide-treated BEDNETS reduce the incidence of
vector-borne diseases by preventing human/vector contact. MALARIA is one
of the planet's deadliest diseases. It is the major public health problem
facing mankind, representing a permanent threat for almost half of the
worldıs population.
According to the World Health Organization there are 300 to 500 million
clinical cases of MALARIA each year resulting in 1.5 to 2.7 million deaths.
In 1992, some 90 countries or territories were considered malarious. For
comparison, in 1955, there were 140 countries or areas where MALARIA was
endemic.
Children under the age of five are the most vulnerable: MALARIA is responsible
for the death of at least one million children annually, half of African
children under the age of five. However, MALARIA is just one of many vector-borne
diseases.
Of
special significance due to the deadly nature of the disease is DENGUE
fever, particularly its more virulent form, DENGUE
haemorrhagic fever.
Over 60% of the world population is exposed to endemic or epidemic DHF.
Each year there are estimated to be tens of millions of cases of DENGUE
fever and hundreds of thousands of cases of DHF, a leading cause of hospitalization
and deaths among children in many countries. The permanent migration of
people between countries, facilitated by modern transportation, puts in
a state of alert those countries whose inhabitants live in regions of
less than 1,800 meters above sea level.
Aedes aegypti, the mosquito which vectors the disease, bites during day
time, therefore, personal protection becomes essential. Drug-resistant
pathogens and pesticide-resistant vectors mean that there are fewer tools
to control MALARIA and other vector-borne diseases. Increasing drug-resistance
makes treatment for MALARIA more costly and less practical. There is no
specific treatment for many vector-borne diseases. This includes DENGUE
fever. There are no commercial vaccines for most vector-borne diseases,
including MALARIA and DENGUE
fever. There is increasing evidence that
aerial insecticides do not significantly reduce the adult mosquito population.
There are serious environmental and ecological problems associated with
the use of aerial insecticides. Vector-borne diseases impose a cost on
individuals, communities and countries in terms of their health and socio-economic
development which is impossible to quantify.
TRENDS THAT WILL ENSURE THE SPREAD OF VECTOR-BORNE
DISEASES AND GROWTH OF THE INSECT REPELLENT MARKET
 |
Unchecked urbanisation and population growth coupled with substandard
housing and inadequate water, sewer and waste management systems.
The increased
use of dams for irrigation and energy generation creating new breeding
grounds for mosquitoes. Increased aeroplane
travel and freight movement transporting pathogens and vectors. The increased
movement of immigrants and refugees from endemic areas to non-endemic
areas. |
MALARIA
AND DENGUE
FEVER IN NORTH AMERICA
MALARIA and DENGUE
fever are not currently established in the US although
they are introduced regularly and have been established there previously.
Travellers returning from endemic regions frequently introduce these diseases
into areas with competent vectors. Between 1 977 and 1 994, 2,248 suspected
cases of imported DENGUE
fever were reported in the US. Legal immigrants,
refugees and illegal immigrants and migrant workers are two possible sources
of introduction of these diseases into the US in amounts sufficient to
promote their establishment. DENGUE
fever and MALARIA are endemic in areas
that are important sources of immigration to the US such as South East
Asia, Mexico, Puerto Rico, and Central/South America. Competent vectors
of MALARIA and DENGUE
fever are established in the US. Even though MALARIA
was eradicated from the US previously, if it were to re-establish itself,
resistance of the vector to pesticides would make present-day control
more difficult. According to Health Canada there were 483 reported cases
of MALARIA in Canada in 1 993, and approximately 431 in 1994. The Centers
for Disease Control and Prevention in the United States received reports
of 910 cases of MALARIA in 1 992 and seven of those cases were acquired
there. In 1 970, reported MALARIA cases in the U.S. were 4,247 with more
than 4,000 of the total being U.S. military personnel.
IMPORTANT VECTOR-BORNE DISEASES IN NORTH AMERICA
Arboviral
encephalitis. At least 18 arbo-viruses cause encephalitis. Seven are present
in the US: Eastern equine encephalitis; Western equine encephalitis; St
Luis encephalitis; California encephalitis; La Crosse encephalitis; Venezuelan
equine encephalitis and Powassan encephalitis. Most cases of arboviral
encephalitis occur between June and September. However, in milder parts
of the country cases can occur into the winter months.
LYME DISEASE
Lyme disease has become the most prevalent arthropod-borne illness in
North America. In 1 997 more than 12,500 cases were reported to CDC by
48 states. There have been over 103,000 cases reported since 1 982. CDC
reports a 25-fold annual increase in reported cases since 1 982. Lyme
disease has also been reported in Germany, Switzerland, France and Austria.
Rocky Mountain Spotted Fever, is a potentially life threatening infection
now recognized as an important cause of illness throughout the USA; some
700 cases are reported annually.
This list demonstrates that even in North America, where there is currently
only a small risk of infection from tropical diseases, biting-insects
present a significant threat to public health. It is our belief that in
the near future climatic changes, migration and international travel and
trade, will ensure that the use of insect repellents in temperate climates,
such as North America, will become more closely associated with disease
prevention, as it is in the Tropics, rather than just with the enjoyment
of outdoor activities.
*Sources : The MALARIA Control Programme, World Health Organization, Third World Network Features, Health Canada, The Centers for Disease Control and Prevention, Health Communications and Public Relations, WHO, Geneva. Manson's Tropical Diseases, XXth. Edition.
