Dengue fever (DF)/Dengue hemorrhagic fever (DHF)/Dengue shock syndrome (DSS); a mosquito-borne viral disease occurs in approximately 390 million people in more than 128 countries annually. Out of which, around 24% are symptomatic leading to severe infections. Global Dengue virus (DENV) transmission has been accelerated by the human mobilization, urbanization and global warming mainly in tropical and sub-tropical climates because of which the prevalence of disease increases drastically in the recent decade. Dengue is one of the major global health problems listed in tropical neglected diseases. Moreover, till date there is no any cure for dengue; treatment is only limited to rehydration therapy, and with vector control strategies seems to be relatively ineffective and vaccines are under licensing. Hence, the only options to reduce the disease burden are to prevent the infection and control as recommended by WHO. These five technical elements need to be implemented scientifically to avoid transmission and adverse effects from the infections.
1. Diagnosis and case management:
Over 80% of dengue viral infection is asymptomatic
which is not detected by a simple rapid serodiagnostic kit. Most of countries are
using those kits in their health care settings and many countries even lack
such kits and do diagnosis simply by blood profiling or platelets count. This
is one of major problems seen because of which a large carrier population are
misdiagnosed. The carriers are the reservoirs of DENV infections and keep on
transmitting the infections to new individuals. The situation alarms us for the
immediate need of highly sensitive and specific diagnostic kits (IgM capture
ELISA, IgG ELISA and RT-qPCR) for proper diagnosis and management of patients
which is a key to overcome this situation. Using those kits in each and every
health care setting and related clinic for definitive diagnosis will not allow
a single case to be undiagnosed. The government, health ministry and
authorities are in the front line to fulfill funding gap and regular monitoring
for these facilities. Like proper diagnosis, good management of positive cases
(patients infected with DENV) needs an equal attention to stop further
transmission and to stop severe dengue related complications. Sufficient number
of trained staff should be appointed for management and extensive care of cases
in all health care facilities. As there is no any specific treatment of DENV
infection, the cases are given supportive care and an emergency team of medical
officers stand back at any time to treat in case of hemorrhage and shock
syndrome. We have to take special precautions for children.
2. Integrated surveillance and outbreak preparedness
As previously mentioned, a single DENV infection may
expand to many cases. Missing of case reporting can be managed by integrated
surveillance. Every year DENV is occurring in new regions due to global climate
change. Those new cases in the new region lead to outbreaks in the areas and
nearby. The surveillance will keep us updated which will be very helpful in
control of epidemics and disease outbreaks. The surveillance system should
collect data on mobile migrant population, vectors, cases and carriers as well
as the tools and techniques used in diagnosis. It should be integrated as a
part to national health system. The system is developed in such a systematic
way that every single case will be reported to the center level. For the
surveillance, mobile data collection tool can be used throughout the system as
it can be used by any laboratory technician to high level authorities and will
be a fastest tool to update. In case of
any outbreak, the management team will handle, manage possible preventive and
control measures. The more quickly the team manage the outbreak, the less
chances to spread and the less will be disease burden.
3. Sustainable vector control
The global warming is an important factor to increase
the vector population even in sub-tropical regions. Aedes aegypti is a
main vector in DENV transmission followed by A. albopictus as a
secondary vector transmitting dengue virus in different regions of world. The potential
vectors should be identified with the help of entomologist and through
extensive surveillance. For the control of vector and vector breeding, WHO
sustainable vector control strategies should be applied wherever possible.
Dengue vector mainly take blood meal at day time, so people should be aware to
use full lengths clothes and use the repellant while working outside. People in
the low-income communities in endemic areas should be provided with insecticidal
treated nets and insecticide spray for internal use. They should be strictly
aware to protect themselves during day hour working in vulnerable regions such
as in agricultural field and in the forest. Most importantly they should be
trained on vector control strategies. Access to water and
sanitation are very important factors in vector control and elimination such as destroying mosquito breeding sites; stagnant
water bodies, removing herbs nearby houses, proper housing, using mosquito
traps etc. Without vector control we can’t think about the control of DENV
infection hence we should focus on it.
4. Future vaccine implementation
Few vaccines are under the progress of licensing.
Vaccines are an alternative tool to eliminate the dengue infection from the world.
However, many of vaccines have antibody dependent enhancement complications.
Few vaccines are only effective in dengue seropositive children while few have
efficacy in older age groups. These all should be considered before we
implement vaccines in the community. We should choose the best one with vaccine
efficacy, gather the demographic information of population (age and location)
to be vaccinated, prepare the necessaries and cost estimation whether we can
cover all the communities or not. Tetravalent live attenuated vaccine,
Dengvaxia is one potential vaccine we can use for children.
5. Basic, operational and implementation research
Besides the
above-mentioned strategies, the implementation should be regularly supervised
and monitored. The monitoring will help
to identify the limitations of implementation strategies. It is only possible
when collaboration from all sectors; government bodies, private sectors,
individual’s effort as well as community level efforts will work together.
Through collaborative works, extensive researches on available tools and
techniques are revised and strengthened, the most suitable kits, tools or
vector control strategies are identified in a particular region and also try to
find early epidemic indicators which can be used for early warming of potential
epidemics and outbreaks. By implementing
these technical elements, we can reduce the disease burden of DENV infection
and meet the goal set by WHO.
(Reference: https://www.who.int/denguecontrol/resources/9789241504034/en/)
