Download YELLOW FEVER SURVEILLANCE KLIA EXPERIENCE

Dr. Azmi bin Abdul Rahim
Public Health Specialist
Health Officer
KLIA Health Office, Sepang, Selangor

Yellow fever is an acute viral haemorrhagic disease
transmitted by infected mosquitoes. The "yellow" in the
name refers to the jaundice that affects some patients 1.

It is caused by the the yellow fever virus, an arbovirus of the
Flavivirus genus and is transmitted by the bite of an infective
Aedes aegypti mosquitoes and by other mosquitoes in the
forests of Africa and South America2.

Up to 50% of severely affected persons without treatment
will die from yellow fever. There are an estimated 200 000
cases of yellow fever, causing 30 000 deaths, worldwide each
year1.

The virus is endemic in tropical areas of Africa and Latin America, with a
combined population of over 900 million people1.

The number of yellow fever cases has increased over the past two decades
due to declining population immunity to infection, deforestation,
urbanization, population movements and climate change1.

There is no cure for yellow fever. Treatment is symptomatic, aimed at
reducing the symptoms for the comfort of the patient1.

Vaccination is the most important preventive measure against yellow fever.
The vaccine is safe, affordable and highly effective, and appears to provide
protection for 10 years or more. The vaccine provides effective immunity
within one week for 95% of persons vaccinated1.

The purpose of this report is to highlight various issues pertaining to Yellow
Fever it’s epidemiology, case definition, diagnosis, treatment and control
globally and the control programmes of this disease in our countries.

Forty-five risk countries in Africa and Latin America, with a
combined population of over 900 million, are at risk. In Africa, an
estimated 508 million people live in 32 countries at risk. The
remaining population at risk are in 13 countries in Latin America,
with Bolivia, Brazil, Colombia, Ecuador and Peru at greatest risk1.

There are an estimated 200 000 cases of yellow fever (causing 30
000 deaths) worldwide each year. Small numbers of imported
cases occur in countries free of yellow fever. Although the disease
has never been reported in Asia, the region is at risk because the
conditions required for transmission are present there3.

The latest list of countries at risk of Yellow Fever is show in the
following Table 4.
AFRICA
CENTRAL AND SOUTH
AMERICA
Argentina2
Angola
Equatorial
Bolivia2
2
Mauritania
Benin
Guinea
Brazil2
2
Niger
Burkina Faso
Ethiopia2
Colombia2
Nigeria
Burundi
Gabon
Ecuador2
Rwanda
Cameroon
Gambia, The
French Guiana
Senegal
Central African Republic Ghana
Guyana
Sierra
Chad2
Guinea
Panama2
Leone
Congo, Republic of the
Guinea-Bissau
Paraguay
2
Sudan
Côte d’Ivoire
Kenya2
Peru2
Togo
Democratic Republic of the Liberia
Suriname
Uganda
Congo2
Mali2
Trinidad and Tobago2
Venezuela2

A traveler’s risk for acquiring yellow fever is determined by various factors,
including immunization status, location of travel, season, duration of
exposure, occupational and recreational activities while traveling, and
local rate of virus transmission at the time of travel1,3,.

Yellow Fever Virus (YFV) transmission in rural West Africa is seasonal, with
an elevated risk during the end of the rainy season and the beginning of
the dry season (usually July–October)3.,.

The risk for infection in South America is highest during the rainy season
(January–May, with a peak incidence in February and March). Given the
high level of viremia that may occur in infected humans and the
widespread distribution of Ae.aegypti in many towns and cities, South
America is at risk for a large-scale urban epidemic1,3,.

The risk of acquiring yellow fever is difficult to predict because of
variations in ecologic determinants of virus transmission.

For a 2-week stay, the risks for illness and death due to yellow fever
for an unvaccinated traveler traveling to an endemic area in:
- West Africa are 50 per 100,000 and 10 per 100,000 respectively
- South America are 5 per 100,000 and 1 per 100,000 respectively 3

Once contracted, the virus incubates in the body for 3 to 6 days,
followed by infection that can occur in one or two phases. The
first, "acute", phase usually causes fever, muscle pain with
prominent backache, headache, shivers, loss of appetite, and
nausea or vomiting. Most patients improve and their symptoms
disappear after 3 to 4 days 1,5,6.

However, 15% of patients enter a second, more toxic phase within
24 hours of the initial remission1,5,6. High fever returns and several
body systems are affected. The patient rapidly develops jaundice
and complains of abdominal pain with vomiting. Bleeding can
occur from the mouth, nose, eyes or stomach. Once this happens,
blood appears in the vomit and faeces. Kidney function
deteriorates. Half of the patients who enter the toxic phase die
within 10 to 14 days, the rest recover without significant organ
damage1,5,6..

In view of Yellow Fever Disease , its carries high percentage of
fatality where by the prevalence rate about 50%. Need to have
stringent surveillance towards yellow fever screening.

Vector that transmitting the disease in other yellow fever
region was the mosquito ( aedes aegpyti) which commonly will
find in our countries. However the vector not been infested
with yellow fever virus in Malaysia

Malaysia situated near equatorial line where sharing
same climates like other yellow fever endemic countries in the
world. Due to same geographical background , probability to
having yellow fever disease is high and is a necessity to
adhere stringent surveillance towards this disease.

Recent year, with country policy
looking at African nation, with more
bilateral collaboration within that
nation as invited exodus movement
of travelers from this particular
region to our country . With this
development, requirement for
screening toward travelers from
yellow fever risk countries become
mandatory and compulsory to
obtain yellow fever vaccination to all
travelers from or via this risk country
should upgraded. 7
Total screened passenger from or via yellow
fever risk countries verses years
40000
26620
30000
28883 30658
19420
20000
10000
7585
11205
0
2005 2006 2007 2008 2009 2010

World Health Organization (WHO) in 1998 in a Yellow Fever
Technical Consensus Meeting, Geneva, 2-3 March 1998 has already
recognized the need of surveillance of Yellow Fever 10.

Suspected Case 5: An illness characterized by an acute onset of
fever followed by jaundice within 2 weeks of onset of the first
symptoms AND one of the following: bleeding from the nose,
gums, skin, or gastrointestinal tract OR death within 3 weeks of the
onset of illness.

Confirmed Case 5: A suspected case that is confirmed by laboratory
results or linked to another confirmed case or outbreak.

Outbreak 5: An outbreak of yellow fever is at least one confirmed
case.

Reporting: Suspected cases of priority disease are reported to the
district level. If yellow fever is suspected, the case is reported
immediately.

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To prevent,control and contain yellow fever
disease out breaks.12,13
Identifying of yellow fever disease that require
immediate health control measures.12
Monitoring yellow fever disease incidence and
distribution, and alert health workers to changes
in disease activity in their area.12
Identifying yellow fever disease out breaks and
support their effective management.12
Assessing yellow fever disease impact and help
set priorities for prevention measures.12 , 13
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Evaluating prevention and control activities.2
Identifying and predicting emerging and re emerging
infectious disease13
Monitoring changes in yellow fever disease agents
through laboratory testing.13
To provide general guidelines and developed a
mechanism for effective implementation of outbreak
management12, 13
Fulfilling mandatory notifiable diseases and
international reporting requirement .12
To collaborate and coordinate activities with other
relevant agencies, both within and outside the
country in managing the outbreak.13
To reduce morbidity and mortality due to yellow fever
disease outbreaks.12 , 13

At this moment Malaysia is free from Yellow Fever
although this country has the yellow fever vector Aedes
aegypti. Malaysia continues to monitor the incidence of
Yellow Fever. This disease has been included in the list of
29 diseases that must be notified under the Infectious
Disease Control and Prevention 1988 (Act 342)8.

Prevention and control at the main entry points is still in
progress. Screening of visitors from Yellow Fever endemic
country or passing through a Yellow Fever affected
country still continues. Any visitor who has visited or
travelled through Yellow Fever endemic country must
possess a valid Yellow Fever vaccination certificate as they
arrive to this country.

Failure to possess a valid certificate will result in them
being quarantined to a maximum of 6 days. At the
same time, all entry point points are also carrying out
vector control activities to ensure that all areas of
airport perimeter and area of ​400m from the
perimeter is vector-free as required by IHR 2005.

At the same time KLIA Health Office also conducts
random inspections of international flight to ensure
that they have carried out insecticide spraying in the
aircraft prior to landing in Malaysia.

Among the objectives of KLIA Health Office is to prevent the entry
of diseases into the country through air travel and also to ensure
the well being of airport users and the general public. With a staff
of approximately 136, KLIA Health Office carries out public health
activities and function through its various units14 as follows :
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Communicable Disease Control Unit
Non-Communicable Disease Control Unit
Health Quarantine Unit
Vector Borne Disease Control Unit
Air Disaster Unit
Food Safety and Quality Unit
Environmental Sanitation and Water Quality Unit
Investigation and Prosecution Unit
Health Promotion Unit
Administration


Surveillance of Yellow Fever is one of the
activities of KLIA Health Office and is carried
out by the Health Quarantine Unit and the
Communicable Disease Control Unit. This
surveillance involves travelers arriving from
various international destinations to KLIA at
the International Arrival Hall, Main Terminal
Building and the Low Cost Carrier Terminal at
KLIA.

To ensure that Malaysia is kept free from Yellow Fever
and this is done by conducting surveillance on arriving
travelers to ensure that they do not bring the disease
in to Malaysia. Malaysia is taking strong
precautionary measures against the introduction of
Yellow Fever as Malaysia is vulnerable and receptive
to Yellow Fever transmission by people who have not
had proper immunization against the disease.

At the same time, vector surveillance is carried out at
KLIA by the Vector Borne Disease Control Unit to
ensure that the airport is free from Aedes aegypti
vector i.e. 400m from point of entry facilities at all
times.11

Travellers arriving in Malaysia within 6 days from the last
date of embarkation from a Yellow Fever endemic country
without a valid vaccination certificate shall be quarantined
at the Health Quarantine Centre upon arrival for a period
not exceeding 6 days i.e. the incubation period of Yellow
Fever.11 The international yellow fever vaccination
certificate becomes valid 10 days after vaccination and
remains valid for a period of 10 years.11,15

However, travellers arriving in Malaysia after 6 days from
the last date of embarkation from a Yellow Fever endemic
country will be allowed entry into Malaysia even without a
valid vaccination certificate as the period has exceeded
the incubation period of Yellow Fever.

Screening for Yellow Fever involving travelers including
distinguished delegates who arrive from/through Yellow
Fever endemic countries.

Carrying out quarantine procedures and surveillance upon
travelers not fulfilling the conditions of a valid Yellow Fever
vaccination certificate in accordance with the
requirements under the Communicable Diseases Act,
1988.

Conducting talks and training to Immigration Officers at
KLIA who are actively involved in assisting KLIA Health
Office in screening arriving international travelers from
Yellow Fever endemic countries to be referred to Health
Quarantine Centre.
Year
No. of Travell Travellers Traveller Travellers
traveller
ers
without s depart with valid
s visited with
valid
from
certificate
YF risk
valid certificate risk YF and depart
> 6 days > 6 days
countrie certific
(0–6
s
days )
ate
YF risk
countries
(0–6
days)
Traveller been quarantined
Travellers under health
surveillance
Non
VIP
VIP
Total
Non
VIP
VIP
Total
9
97
1
72
2
2
0
45
35
26
14
275
2006
11205
8805
378
2022
10827
281
0
281
2007
19420
15962
498
2960
18922
426
0
426
2008
2009
2010
26620
28884
30658
23424
26800
29250
440
217
149
2756
1867
1259
26180
28710
30482
395
182
123
0
0
0
395
182
123
88
(*A )
71
(*B )
43
33
26
Total
116787 104241
1682
10864
115121
1406
0
1406
102

In ensuring the airport is free of Aedes aegypti, KLIA Health Office has
implemented two methods of monitoring which is Aedes inspection and
Ovitrap study.

Ovitrap study is carried out to detect the presence of Aedes and is an
indicators of the existence of the Aedes mosquito and it’s species in the
vicinity. It is done within the perimeter of airport up to 400meter from
the perimeter. Ovitrap study is carried out using Mosquito Larvae
Trapping Devices or MLTD. Installation of traps and reexamination is
done every seven days (the mosquito aedes aegypti life cycle).

In accordance with IHR 2005 all entry points should be free from Aedes
aeypti (Ovitrap Aedes aegypti should be 0 )11 and Overall Aedes Index
should be less than 10% (< 10%). Studies carried out by KLIA Health
Office from 2006 until 2010 shows that, KLIA has been free from Aedes
aegypti until 2009 (Chart 1) however breeding has been found in the year
2010.
30
27
17
20
15
7
10
0
10
0
0
0
0
1
2006
2007
2008
2009
2010
Aedes albopictus Aedes aegypti
10
8
6
4
2
0
8
8
5
4
4
0
2006
9
0
2007
0
2008
Aedes albopictus
0
2009
Aedes aegypti
2010
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Inspection of any international aircraft was carried out
starting from 2003 and implemented with the objective to
ensure no disease-bearing insects brought into Malaysia
and to monitor the cleanliness of international aircraft.

This procedures required the flight operator to makesure
that the disinsectisation had been done before landing at
any of international airport in Malaysia. Disinsectisation
can or documents of disinsectisation must be submitted /
sent to the Health Quarantine Center to be reviewed by
our officer.

Compliance of vaccination requirement among the travellers from
Yellow Fever Risk Countries has improved however there are still
travellers who fail to produce vaccination certificate on arrival.
Among the reasons quoted is unaware of this requirement.

The existing monitoring mechanism for Malaysian arriving from
Yellow Fever Risk Countries whereby random check are carry out
at the Immigration autogate is insufficient to ensure compliances
among Malaysian.

The travellers from Yellow Fever Risk Countries are referred by the
Immigration officer to Health Quarantine Centre at entry point.
However there are travellers who are not referred by
Immigrations. This could be due to high turnover of Immigration
Officers at entry point.

Owners of premises within the airport had been found to
be ineffective in their effort to identify and control the
breeding and potential breeding areas.
Pest control operators (PCOs) appointed by the airport
authorities have not played an important role in
preventing breeding of Aedes.

Disinsectisation of inbound international flight have not
satisfactorily carried out by flight operators as required
under IHR 2005. Disinsectisation is important to prevent
the disease bearing vector transmission into Malaysia. At
this moment this is not legal requirement.

To improve the compliance among arriving travelers it is
suggested that awareness activities need to be enhance
further.

To improve the awareness among Malaysians who travel to
Yellow Fever Risk Countries, travel agencies and Embassy
(Malaysia and Foreign) should play an important role to
ensure this vaccination requirement is emphasize prior
travelling to Malaysia. This can be done by distributing
brochures and through their website.

Regular briefings and training on Yellow Fever requirement
to Immigration Officers can increase referrals of travellers
from Yellow Fever Risk Countries to Health Quarantine
Centre.

Regular education activities on prevention on mosquito
breeding and the enforcement of Destruction of DiseaseBearing Insects Act 1975 amended in 2000 will be enhanced
to curb Aedes breeding at KLIA by enforcing the maximum
compound without allowing appeal for reduction

Activities by the PCOs should monitored closely in ensuring
the activities carry out are effective in preventing Aedes
breeding.
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Regulation related to disinsectisation requirement which is
being drafted at Ministry of Health should be expedited.

Thank you for your attention
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WHO 2011 – fact sheets of YF from http://www.who.int/mediacentre/factsheets/fs100/en/
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WHO 1998 (2) - District guidelines for yellow fever
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Laws of Malaysia Act 342 Prevention and Control of Infectious Disease Act
Case Definitions for infectious Diseases in Malaysia, 2nd Edition 2006, Ministry of Health Malaysia
WHO (1998) , Yellow fever – Technical Consensus Meeting. Geneva, 2-3 March 1998
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Infectious Diseases Outbreak, Rapid Response Manual
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Laporan Teknikal dan Pengurusan Pejabat Kesihatan KLIA 2010. (Unpublished)
Yellow Fever Vaccination Requirements and Reccomendations
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Bernama –Tue,June 2011 : African Nations and Malaysia must Tap resources in Agri sector