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 Administrative Arrangements for Control of
DHF Epidemics
It is necessary that a mechanism be established at
national, state and local levels for the creation of a multi-disciplinary
emergency action committee (EAC) and a rapid action team (RAT). EAC will
mobilize all resources of health and non-health sectors, the media, NGOs,
school/colleges, student manpower and communities at large in order to
coordinate prompt actions for emergency interventions. The rapid action team,
under the direction of EAC, should have the capacity to be mobilized at short
notice to carry out epidemiological investigations and control measures.
Recommendations
a)
For WHO/SEARO
The
existing regional rapid response team at SEARO should be strengthened and
expanded to include Member States to support emergency management of DHF as
requested or required by country(ies).
b)
For Member States
1. The
EAC and RAT should be established at national, state and local levels to take
early action for management of DHF outbreaks.
2. Inter-sectoral partnerships should be established at national
and local levels with all related sectors to control epidemics.
3. An
official spokesperson, (i.e. public information officer) should be designated
at national, state and local levels, to provide accurate information to the
public through inter-personal communication and the mass media regarding DHF
outbreaks.
Preparation and Organization of Medical
Care Before and During Epidemics
During the past two decades the DEN/DHF incidence has
been increasing every year in the countries of the Region. However, where DHF
has appeared as a newly emerging disease, the case fatality rates are high,
apparently due to lack of awareness of the standard management of cases. It
is essential that DHF management skills need to be improved not only among
health personnel but also in the management and organization of medical care
services before and during epidemics. Recommendations are made as follows:
a)
For WHO/SEARO
1. To develop standard comprehensive training
modules for use in emergency preparedness for case management of DHF/DSS.
2. The revised version of the 1986 manual on
diagnosis, treatment and control of DHF should be made available to the
Member Countries as early as possible.
3. WHO should support Member Countries on
research and training by way of expertise and for exchange visits of scientists
within the SEA Region.
b)
For Member Countries
1. Health personnel, especially physicians,
should be oriented to the standard clinical case diagnosis and management by
(i) providing WHO Case Management Guidelines for
DEN/DHF/DSS; (ii) conducting training courses using standard training
modules, and (iii) incorporating DEN/DHF into the curriculum in medical
schools, schools of nursing and schools of public health as a long term
measure.
2. Ensure that medical facilities where dengue
patients are admitted are free from Aedes
mosquitoes by eliminating breeding sources (e.g. a distance of 500 meters
circumference) and equipped with mosquito screens to prevent further
transmission of infection.
c) For provincial/municipal/district
health authorities
1. Health facilities including private
practitioners in peripheral areas where basic laboratory and treatment
facilities are not available, health personnel should be trained to recognize
important signs and symptoms of DEN/DHF/DSS and should refer the patients to
hospital when suggestive signs of haemorrhagic
manifestation or shock are detected.
2. A suitable referral system with appropriate
transport facilities should be established.
Standard Case Management of DHF/DSS
For effective individual case diagnosis and management
of DHF/DSS, laboratory support is essential. The following steps are
recommended:
a)
For Member Countries
1. The guidelines for Clinical Diagnosis and
Management of Dengue and Dengue Hemorrhagic Fever in the WHO/SEARO Monograph
No. 22 are appropriate for use by all physicians. It should be strictly
followed, particularly for monitoring of platelet counts and haematocrit value and the amount and period of fluid
replacement. Invasive procedures like gastric intubation is contraindicated as it causes haemorrhage. The use of salicylate
analgesic (i.e. aspirin) is strongly contraindicated.
2. During outbreaks, all patients with high fever
(38.5°C or higher) should be screened for dengue by Tourniquet test using
appropriate-size sphygmomanometer cuff. All health facilities should be
encouraged to establish at least one observation room for observing
suspected cases of DHF for early detection of haemorrhagic
manifestations and/or shock.
3. Clinical laboratory services should be
established to function on 24-hours basis in order to monitor platelet and haematocrit levels and to start early fluid replacement,
if indicated. It is desirable that separate arrangements (units, ward) for
DHF/DSS patients be established and specially trained staff should be
deployed to properly monitor and manage DHF/DSS cases. Basic laboratory
facilities (microhaematocrit, microscopes, microcentrifuge) for total
differential cell counts and haematocrit platelet
counts should also be attached to the DHF/DSS wards.
4. Laboratory support should be strengthened for
the diagnosis and management of dengue. Two types of laboratory tests are
used for different purposes: (i) For
individual case diagnosis and management, basic laboratory tests are
essential in all health facilities. The hospital laboratory should also have
the capability to test blood coagulogram, blood electrolytes, blood gas and liver function tests,
and (ii) serological tests should be used for specific, etiological diagnosis
and epidemiological surveillance. A small sample (5%) of all suspected dengue
cases should be sufficient. Attempts should be made to collect paired samples
at acute stage on admission and at convalescent stage on discharge. Virus
isolation should be considered a special study.
Laboratory Diagnostic Facilities
At present there is no standardized rapid test for
dengue infection. For MAC-ELISA and other serological tests, timely
availability of reagents is necessary. Therefore, there is a need for timely
supply of required reagents. The recommendations are as follows:
a)
For WHO/SEARO
1. SEARO should consider designating additional arboviral WHO collaborating centres
in the Region and strengthening existing centres in
order to support increased production of viral reagents.
2. Rapid diagnostic test kits should be
standardized by a WHO panel of experts which can provide rapid, dependable
results.
b)
For Member States
National
virology reference centres should be strengthened
and the availability of necessary reagents and other laboratory supplies
which are required for the timely determination of virus serotypes should be
ensured.
Disease Surveillance System
In order to prevent and control epidemics, it is
essential to have a full understanding of the epidemiological patterns based
on an effective disease surveillance system established at regional, national
and local levels. The recommendations are:
a)
For WHO/SEARO
SEARO
should assist Member Countries to strengthen and coordinate surveillance
activities on a regular basis in order to determine trend analysis, provide
feedback to Member Countries and exchange information.
b)
For Member Countries
Countries
of the Region should develop and strengthen their disease surveillance
systems on a regular basis to determine trends and early warning signs of the
disease outbreak. DHF should be declared as a reportable/notifiable
disease. Existing legal frameworks should be reviewed and steps taken to
empower local authorities and/or state governments to monitor,
prevent and control epidemics.
c) For Provincial/Municipal/District
Authorities
Approximately
5 per cent of the clinical diagnosis of dengue/DHF cases should be confirmed
at the beginning of the transmission season by laboratory diagnosis. The
information can be linked to vector control measures in order to reduce
vector population.
Vector Surveillance and Control
In the absence of any vaccine or drug for treatment of
infection, the choice for prevention and control of DEN/DHF epidemic falls on
vector control. Information about vectors and their control is required to
develop cost-effective control strategies. The recommendations are:
a)
For WHO/SEARO
1. SEARO should develop a manual and
guidelines on contingency vector control to deal with the epidemic situation.
2. SEARO should organize intercountry workshops on vector surveillance and its
control so that Member Countries can adopt appropriate strategies suiting
local conditions.
b)
For Member Countries
1. Member Countries should carry out
vector surveillance in epidemic potential areas to bring out information on
vector dynamics and possible risk factors.
2. It is necessary for countries to
develop appropriate entomological assessment for effective implementation in
order to monitor vector control activities and assess the impact on vector
population.
c) For Provincial/Municipal/Districts
Authorities
1. During the dengue outbreaks, immediate action
is essential to identify local areas where transmission is occurring. Local
authorities should develop mechanisms to conduct epidemic investigation and
apply remedial vector control measures.
2. Local authorities should convey a clear
message that members within communities should undertake source reduction
measures in and around their houses and protect themselves by using available
protective measures. They should be encouraged during DHF epidemics to
cooperate with municipal health authorities with regard to control
activities.
Capacity-Building
A cadre of trained workers and scientists forms the
backbone for the success of any disease control programme,
and DHF control is no exception. Therefore, there is a need for building up
competency-based course curricula and arranging trainers' training programme in all aspects of disease surveillance and
outbreak management. The recommendations are:
a)
For WHO/SEARO
1. SEARO should organize a workshop
to design a study on silent dengue transmission. Where resources permit,
Member Countries may choose to establish a prospective study of a selected
population in a study site. DEN/DHF cases, dengue transmission patterns,
vector densities and other parameters of epidemiological significance should
be correlated to determine factors favourable for
silent dengue transmission.
2. Technical guidelines for epidemic
management of DHF should be developed by SEARO for the Member States to adopt
according to local capacity.
b)
For Member Countries
1. National dengue prevention and
control programmes should be established and
existing programmes should be further strengthened
at each infrastructural level with the appointment of qualified staff. In
countries where urban malaria programmes exist,
merging of dengue control with these programmes may
be considered.
2. Logistical support for the
management of outbreaks in the Member Countries should be further
strengthened at regional, national and local levels. Manpower mobilization
should be strengthened by creating awareness through workshops and seminars
to fight epidemics.
3. Training courses should also be
developed to improve the competency of health personnel at all levels in
order to implement effective DHF epidemic control measures.
Research on DEN/DHF/DSS
There was an urgent need for developing basic research
to understand the epidemiological complexities of the disease and operational
research and training was required to develop cost-effective control
strategies and their implementation. Socio-cultural habits, beliefs and
prejudices of communities not only promote building up of breeding potential
for dengue vector but also come in the way of implementing control
strategies. The recommendations are as follows:
a)
For WHO/SEARO
SEARO
should arrange to make an inventory of dengue viruses isolated from DEN/DHF
cases in each country and coordinate genotyping studies at WHO collaborating centres.
b)
For Member Countries
1. Countries should investigate the distribution
of the genotype of dengue viruses in collaboration with SEARO and WHO
collaborating centres.
2. Countries should conduct a study to identify
their early warning system for detection of virus circulation, based on local
capacity, by which future epidemics may be determined before they become
explosive outbreaks.
3. To identify indicative signs/symptoms or
simple laboratory tests which can predict haemorrhage
or shock in dengue cases.
4. Study reliable rapid laboratory diagnostic
technology.
5. There was a need for developing more sensitive
and applicable entomological parameters to correlate mosquito population
densities with dengue transmission rates.
6. Current vector control survey methods need to
be reassessed to take into consideration prevailing socio-cultural conditions
and vector control measures to determine which can be utilized effectively in
a cost-effective and sustainable manner.
7. An in-depth study on the bioecology
of the two ecological variants of Aedes aegypti be conducted in order to determine ecological
consequences of environmental changes and vector breeding as related to
dengue transmission and to develop rational control strategies.
8. Ways and means by which communities can be
mobilized for DEN/DHF outbreaks should be considered. In this regard a
well-defined and simple community action for control of vectors should be
prepared, and how the same should be communicated to the people needs to be
defined.
9. Social/behavioural
research should be strengthened to improve communication at the community
level for better prevention and control of DHF: knowledge, attitude, belief
and practice (KABP), including culturally-sensitive health messages.
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