Chikungunya - An Emerging Threat to Bangladesh by Dr. Syeda Zerin Imam

CHIKUNGUNYA AN EMERGING
THREAT TO BANGLADESH
(Part-Orientation)
By
Dr. Syeda Zerin Imam

INTRODUCTION:
The generation and re-generation of diseases involves many interrelated factors.
Global inter-connectedness propagate international travel and trade by
amplifying economic, political and cultural interactions and along with that
human to human and human to animal interactions. These interactions include
the accidental and deliberate sharing of microbial agents and anti microbial
resistance and allow the emergence of new and unrecognized microbial agents.
As the 21st century begins these two slowly evolving systems microbial life and
human life are found profoundly modified in an unprecedented manner by a third
player, human civilization and its global impact through physical, chemical,
societal and climatic determinants. As a result number of new agents has been
identified and new outbreaks have occurred. An appreciation of the evaluation of
infectious diseases in this new century demands a full understanding of three
domains: human physiology, microbiology and the environment. Eventually
solutions to limiting the spread of emerging infectious diseases will require
cooperative efforts among many disciplines and entities worldwide.
Being a country of this global village Bangladesh is experiencing the emergence of
a new vector borne disease named ‘Chikungunya’. Though it is classified as an
endemic disease category but the ultimate effect of this disease is no less than an
epidemic one.
03-Apr-18 Dr. Syeda Zerin Imam 2

PREFACE OF BANGLADESH:
Bangladesh is the world’s eighth most populous country located in
south Asia at the tropic of cancer. The country has its 4156 km border
with India on the east, west and north and by the Bay of Bengal in the
south and has another 193 km with Myanmar on the south-east.
Bangladesh is the largest delta on the earth having 700 rivers and
8,046 km (5,000 miles) of inland waterways. High lands with
evergreen forests are found in the north eastern and south eastern
regions of the country.
The longest unbroken sea beach, Cox's Bazar Beach is located here. It
is home to the Sundarbans, the largest mangrove forest in the world.
The country's biodiversity includes a vast array of plant and wildlife,
including endangered Bengal tigers, the national animal. But the
country continues to face challenges in the areas of poverty,
education, health care and corruption.

Map of Bangladesh
https://www.mapsofworld.com/bangladesh/bangladesh-political-map.html

Asian countries
https://www.pinterest.co.uk/goyesko/asia/?lp=true

Climate and weather: climate of Bangladesh is tropical with a mild winter
from October to March and a hot humid summer from March to June. A
warm and humid monsoon season lasts from June to October and supplies
most of the country’s rainfall.
From the WORLD CLIMATE GUIDE we can get the following information:
• The climate of Bangladesh is tropical, with a pleasantly warm and sunny
winter from November to February,
• a short hot spring between March and May and
• a long rainy season from June to October, due to the summer monsoon.
The country is flat and occupied by the huge Ganges-Brahmaputra Delta,
and is therefore exposed to floods, as well as to storm surges when
cyclones hit the Bay of Bengal.

Specification of the weather:
The dry season runs from November to March. The monsoon leaves the country
during the month of October but sometimes rain may lasts until November,
especially in the south east region or when a late cyclone arrives. In general
November is hot but not too much with highs around 30◦C (86◦ F) and sunny.
The winter proper begins in December and is characterized by warm and sunny
days followed by cool nights. In February the temperature begins to rise and
from March it begins to get really hot.
From March to May, it is spring, actually the hottest season: the average
maximum temperatures reach 35◦C (95◦F) in April and in inland areas they don’t
go above 32/33◦C (90/91◦ F). Relative humidity gradually increases and the heat
becomes more stifling. The real monsoon arrives from late May to early June,
starting from the south east. It brings a more compact cloudiness, high humidity
even during the day, frequent rains and a decrease in temperature, which drops
to 30/32◦C (86/90◦ F) during the day but remains high at night about 25◦C (77◦
F). The monsoon gradually withdraws between October and November. The sun
in Bangladesh shins regularly in the dry season but in the monsoon (June-
September) it is rarely seen.

Capital and largest city Dhaka 23◦ 42’N 90◦21’E
Official Language & National Language Bengali
Ethnic Group 98% Bengalis & 2% Minotiries
Religion 90% Islam, 9.5% Hinduism, 0.3%
Buddhism & 0.2% Christianity.
Area Total – 147,570 km2 (56,980 sq mi)
Water – 6.4%
Population 2016 estimate – 162,951,560 (8th)
2011 census – 149,772,364 (8th)
Density – 1,106/km2 (2,864.5/sq mi) (10th)
GDP (PPP) 2018 estimate
Total - $748.811 billion (31st)
Per capita - $4,541 (139th)
GDP (Nominal) 2018 estimate
Total $273.618 billion (43rd)
Per capita $1,660 (148th)
HDI (2015) ↑0.579 – medium (139th)
Currency Taka - BDT
Time zone BST (UTC+6)
BANGLADESH AT A GLANCE
Source: https://en.wikipedia.org/wiki/Bangladesh03-Apr-18 Dr. Syeda Zerin Imam 8

Chikungunya is a mosquito-borne viral disease first described during an outbreak in
southern Tanzania in 1952. It is an RNA virus that belongs to the alphavirus genus
of the family Togaviridae. The name “chikungunya” derives from a word in the
Kimakonde language, meaning “to become contorted”, and describes the stooped
appearance of sufferers with joint pain (arthralgia).Chikungunya is transmitted to
humans through the bite of an infected mosquito from the Aedes species, which is
present in Bangladesh. This is the same mosquito that is responsible for dengue
and zika infections. They mainly bite during the day. Chikungunya is
an infection caused by the chikungunya virus (CHIKV). The virus may circulate
within a number of animals including birds and rodents.
PREFACE OF CHIKUNGUNYA

INTRODUCTION OF THE MOSQUITO
Classification:
KINGDOM – Animalia
PHYLUM - Arthropoda
CLASS – Insecta
ORDER - Diptera
FAMILY - Culicidae
GENUS - Aedes
SPECIES – albopictus/aegypti

Physical structure:
Mosquitoes have 2 wings, a proboscis, 6 legs and 3 body regions:
A. Head- it has:-
1. A proboscis – to suck the nectar
2. Two compound eyes – to perform precise attacks
3. Two antennas – to the movement in the air and to differentiate
male female mosquitoes.
B. Thorax- It has:-
1. Prothorax- it is nearest to the head and contains a pair of legs and a
pair of spiracles to supply air into the mosquito’s body.
2. Mesothorax- the middle section of the thorax that holds a pair of
legs and a pair of wings.
3. Meta thorax- the last/ back part of thorax that holds a pair of legs.
C. Abdomen- the last part of the mosquito body having 10 segments. All the
segments contain spiracles except 1st, 9th and 10th segments.
The 9th segment contains gonopore, which is a hole for sexual material to pass.
The 10th segment contains the male or female reproductive organ, depending in
the sex of the insect.03-Apr-18 Dr. Syeda Zerin Imam 11

Life cycle:
From the United States Environmental Protection Agency (EPA) we have come to know
about the different stages of the mosquito life. All Mosquito species go through four
distinct stages during their life cycle.
1. Egg – hatches when exposed to water.
2. Larva – (plural: larvae) “wriggler” lives in the water; molts several times; most species
surface to breath air.
3. Pupa- (plural: pupae) “tumbler” does not feed; stage just before emerging as adult.
4. Adult – flies short time after emerging and after its body parts have hardened.
The first three stages occur in water, but the adult is an active flying insect. Only the female
mosquito bites and feeds on the blood of humans or other animals.
After she obtains a blood meal, the female mosquito lays the eggs directly on or near water,
soil and at the base of some plants in places that may fill with water. The eggs can
survive dry conditions for a few months.
The eggs hatch in water and a mosquito larva or "wriggler" emerges. The length of time to
hatch depends on water temperature, food and type of mosquito.
The larva lives in the water, feeds and develops into the third stage of the life cycle called, a
pupa or "tumbler." The pupa also lives in the water but no longer feeds.
Finally, the mosquito emerges from the pupal case after two days to a week in the pupal
stage.
The life cycle typically takes up two weeks, but depending on conditions, it can range from 4
days to as long as a month.
The adult mosquito emerges onto the water's surface and flies away, ready to begin its
lifecycle.03-Apr-18 Dr. Syeda Zerin Imam 13

Source: National Center for Emerging and Zoonotic Infectious Diseases

TRANSMISSION OF CHIKUNGUNYA
Most commonly, the mosquitoes involved are Aedes aegypti and Aedes albopictus,
two species which can also transmit other mosquito-borne viruses, including dengue.
These mosquitoes can be found biting throughout daylight hours, though there may be
peaks of activity in the early morning and late afternoon. Both species are found biting
outdoors, but Ae. aegypti will also readily feed indoors. After the bite of an infected
mosquito, onset of illness occurs usually between 4 and 8 days but can range from 2 to
12 days.
There are two types of transmission:
•Local transmission: A person with no recent history of travel to an area with the virus
who gets bitten by a mosquito infected with chikungunya virus where they live, work
or play.
•Imported case: A person who has recently traveled to a country or region with cases
of chikungunya who gets bitten by an infected mosquito while traveling and gets sick
after returning to his/her own country.

Symptoms
This disease is biphasic:
1st phase: It consists of fever & severe joint, limb & spine pains. Myalgia &
conjunctivitis may also be present. It may last for 6-10 days.
2nd phase: It begins after a febrile period of 2-3 days & is associated with an
irritating rash over the body, particularly on surface of the limbs. Joint pain
may persist occasionally without fever, for up to 4 months. Bleeding from
gums & a positive tourniquet test have been seen in many patients & may
lead to the infection being mistaken for dengue.
Mortality rate is estimated at 0.4% but in patients aged less than one year, it is
as high as 2.8% & similarly in those aged more than 50 years, death rate
increases.
Incubation period: It is usually 2-3 days, with a range of 1-12 days.

Mosquito bite (Day time)

Symptom
1. Fever and headache
2. Rash
3. Joint pain

Clinical Features:
Chikungunya is an acute infection of abrupt onset characterised by fever &
arthralgia, followed by other constitutional symptoms and rash & lasting
for a period of one to seven days.
1) Fever: Fever rises abruptly often reaching 39 to 40 degree centigrade
accompanied by intermittent shaking chills. This acute phase lasts two to
three days. The temperature may remit for one to two days, resulting in a
‘saddle-back’ fever curve.
2) Joint-Pain (Arthralgia):
Pain on movement is worse in the morning improved by mild exercise.
Swelling may occur but fluid accumulation is uncommon.
Patients with milder articular manifestations are usually symptom free
within a few weeks, but more severe cases require months to resolve
entirely & may lead to crippling arthritis.
Generalised myalgias as well as headache, back & shoulder pain is common.
Chronic joint pains are seen in about 1 in 10 cases of Chikungunya infection
and may be mistaken for rheumatoid arthritis.

3) Cutaneous manifestation: A flush over the face & trunk, usually followed
by a rash generally described as maculo-papular may appear. Sometimes
rashes are accompanied by severe itching.
4) Photophobia & retro-orbital pain may also occur but not severe.
Conjunctival infection is present in some cases.
5) Although rare, the infection can result in meningo-encephalitis especially
in newborns & those with pre-existing medical conditions.
6) In pregnant woman the biggest risk is the possibility of transfer of virus to
the foetus. In addition, delivery becomes complicated if the infection starts
late in the pregnancy sometimes requiring caesarean section. The virus is
not transmitted through the breast milk.
7) Chikungunya can be deadly for very old and newborns.

Case definition:
Suspect case: An acute illness characterized by sudden symptoms of fever with
several of the following symptoms-joint pain, headache, backache,
photophobia and rash.
Probable case: As above & positive serology (when single serum sample is
obtained during acute phase or during the convalescence).
Confirmed case:
A probable case with any of the following:
1. Fourfold HI antibody difference in the paired serum sample.
2. Detection of IgM antibody.
3. Virus isolation from serum.
4. Detection of Chikungunya with virus Nucleic acid in sera by RT-PCR.
5. Complete Blood count
6. SGPT
7. C-Reactive Protein

Three main laboratory tests are used for diagnosing Chikungunya fever:
Virus isolation.
1. Serological tests of Blood in plain vial/serum
2. Molecular diagnosis by Polymerase Chain Reaction
Time of collection:
1st sample: 5 days after onset of illness for IgM detection as these antibodies
appear at this time.
2nd sample: At least 7-10 days after the 1st sample.
Treatment:
1. There is no specific treatment for Chikungunya. Main purpose of treatment
is the management of fever and pain.
2. Non-aspirin & non-steroidal anti inflammatory drugs are recommended.
There is no role of antibiotics & antiviral agents.
3. Movement & mild exercise tend to improve stiffness & morning joint-pain
(Arthralgia).
4. A healthy diet with fruits and vegetables and good sleep promote early
recovery.

Prognosis:
1. Chikungunya is rarely fatal. Recovery from the disease varies by age.
Younger patients recover within 5 to 15 days; middle-aged patients
recover in 1 to 2.5 months.
2. Recovery is longer for the elderly.
Vaccine against Chikungunya:
1. Currently there are no vaccines available in the market for preventing
Chikungunya.
2. However scientists have developed an experimental Chikungunya
vaccine, that contains noninfectious virus-like particles that enables
Chikungunya virus to pass through cell walls.
3. However, these particles do not contain replicable Chikungunya-proteins
and hence is harmless but to be used with caution.

Chikungunya virus (CHIKV) comes from
Togaviridae family and Alphavirus genus.
It is 60-70 nm diameter enveloped
spherical virus with positive single-
stranded RNA genome. Its length is
approximately 12 kb long and has 2 ORF
(Open Reading Frame). One ORF encode
for 5 structural proteins (C, E3, E2, 6K,
E1) and another one encode for 4 non-
structural proteins (nsP1, nsP2, nsP3,
nsP4). These E proteins are used as
receptor binding and antibodies
neutralization. Chikungunya virus is
divided into 3 genotypes based on
geographical origins: The Asian, the West
African, and the East, Central, and South
African (ECSA).
MICROBIOLOGICAL FINDINGS OF THE DIASESE: Cryoelectron microscopy
reconstruction of chikungunya virus

Chikungunya Virus: Computer illustration
Chikungunya virus: Here we can see a
computer illustration. Chikungunya Virus is
composed of RNA (Ribonucleic acid)
genome enclosed in a protein coat or
nucleocapsid (Shown Here), which is itself
surrounded by lipoprotein envelop.
Virus Classification
Group Group IV ((+)ssRNA))
Order Unassigned
Family Togaviridae
Genus Alphavirus
Species Chikungunya virus

Pathogenesis of Chikungunya

GEOGRAPHICL DISTRIBUTION OF DISEASE
1. Prior to 2013, chikungunya virus outbreaks had been identified in
countries in Africa, Asia, Europe, and the Indian and Pacific
Oceans.
2. In late 2013, the first local transmission of chikungunya virus in
the Americas was identified in Caribbean countries and territories.
Local transmission means that mosquitoes in the area have been
infected with the virus and are spreading it to people.
3. Since then, local transmission has been identified in 45 countries
or territories throughout the Americas with more than 1.7 million
suspected cases reported to the Pan American Health
Organization from affected areas (Updated data from PAHO).

Source: National Center for Emerging and Zoonotic Infectious Diseases ( NCEZID)
Source: https://www.cdc.gov/chikungunya/geo/index.html

AFRICA
1. Benin
2. Burundi
3. Cameroon
4. Central African Republic
5. Comoros
6. Democratic Republic of the Congo
7. Equatorial Guinea
8. Gabon
9. Guinea
10. Kenya
11. Madagascar
12. Malawi
13. Mauritius
14. Mayotte
15. Nigeria
16. Republic of Congo
17. Reunion
18. Senegal
19. Seychelles
20. Sierra Leone
21. South Africa
22. Sudan
23. Tanzania
24. Uganda
25. Zimbabwe

ASIA
1.Bangladesh
2.Bhutan
3.Cambodia
4.China
5.India
6.Indonesia
7.Laos
8.Malaysia
9.Maldives
10.Myanmar (Burma)
11.Pakistan
12.Philippines
13.Saudi Arabia
14.Singapore
15.Sri Lanka
16.Taiwan
17.Thailand
18.Timor
19.Vietnam
20.Yemen
EUROPE
1.Italy
2.France
OCEANIA/PACIFIC ISLANDS
1. American Samoa
2. Cook Islands
3. Federal States of Micronesia
4. French Polynesia
5. Kiribati
6. New Caledonia
7. Papua New Guinea
8. Samoa
9. Tokelau
10. Tonga

1.Anguilla
2.Antigua and Barbuda
3.Argentina
4.Aruba
5.Bahamas
6.Barbados
7.Belize
8.Bolivia
9.Brazil
10.British Virgin Islands
11.Cayman Islands
12.Colombia
13.Costa Rica
14.Dominica
15.Curacao
16.Dominican Republic
17. Ecuador
18. El Salvador
19. French Guiana
20. Grenada
21. Guadeloupe
22. Guatemala
23. Guyana
24. Haiti
25. Honduras
26. Jamaica
27. Martinique
28. Mexico
29. Montserrat
30. Nicaragua
31. Panama
32. Paraguay
33. Peru
34. Saint Barthelemy
35. Saint Kitts and Nevis
36. Saint Martin
37. Puerto Rico
38. Sint Maarten
39. Saint Lucia
40. Saint Vincent and the
Genadines
41. Suriname
42. Trinidad and Tobago
43. Turks and Caicos Islands
44. United States
45. US Virgin Islands
46. Venezuela

EPIDEMIOLOGY AND GLOBAL EXPANSION OF CHIKUNGUNYA WORLD WIDE
Phylogenic analysis has revealed four different genotype of CHIKV on the
basis of geographical regions.
The West African genotype consists of isolates from Senegal and Nigeria.
The East Central/ South African (ESCA) genotype is another genotype enzootic
in Africa.
Isolates from Asian countries are included in the Asian genotype.
The more recent Indian ocean lineage (IOL) genotype spread from the
Comoros islands in 2004 and results in severe epidemics in Southeast Asia
and India during the years 2005-2008.
In the following table we can see the epidemiological findings of CHIKV across
the globe.

source: International Journal of infectious diseases 58(2017) 69-76

Source: International Journal of infectious diseases 58(2017) 69-76

CHIKUNGUNYA ATTACK TREND IN BANGLADESH
In Bangladesh the first attack was in 2008 in Rajshahi and
Chapainawabganj districts. After that another outbreak was found in 2009
in Pabna district. After that the Institute of Epidemiology, Diseases Control
ad Research (IEDCR) noticed the presence of the disease in Dhaka 2011.
Again in 2017 the third outbreak was found in capital Dhaka, Dohar and
Nababgonj and also in Shibgonj of Chapainababgonj.

REASON BEHIND THE RESEARCH
1. Chikungunya is a debilitating disease. It makes the patients unable to
work for a long time. Being ‘unable to work’ for a long time of a family
member can cause an economic burden to the family. In a country like
Bangladesh it is not possible to stay workless and earning less for a long
time. So in the long run it is a dangerous threat to the people of medium
or low income status.
2. Even after being at the first position of the Asian country in the
geographical distribution of the disease no effective measures have been
taken by the government of the respective country. But the situation of
attack of this disease is worsening day by day. So it is essential to take
necessary steps to prevent the disease.

DETERMINANTS OF THE DISEASE
The factors that are will makes the victim vulnerable to the contamination
are called the determinants. From different researches we could come to
know about the following factors causing the “Chikungunya Fever”:
1. Poor Sanitation – poor sanitation factor have the following variables
• Water distribution
• Water storage
• Waste disposal
• Stagnant water
2. Housing condition – different housing conditions are important factor
for the contamination. Different housing conditions can be described
as the following points:
• Brick build house
• Non – brick house
• Incomplete house
• Tin shade
• Slum home

3. Education – Level of education is important for the responsiveness to
the anti mosquito measures. Along with that prevention, management
and treatment of the diseases.
• Illiterate
• Primary
• Secondary
• Graduate
• Postgraduate
4. Environment and domestic factors – these factors are actively
responsible for the transmission of the disease. Factors include the
following:
• Remote or hilly area
• Mosquito menace present
• Domestic animals presence
• Water holding containers inside the home
• Peri -domestic container
• Presence of large water bodies; lakes, ponds, river etc.

5. Weather and climate - Daily rainfall, temperature and relative humidity data
at nearby meteorological stations from the vector survey areas (1–7 km)
should be obtained from Department of Hydrology and Meteorology (DHM).
Using the data on these climatic variables, we assessed their association
with the abundance of each species of mosquito. Generally hot and warm
weather is the best breeding condition of the vector. According to the
weather information narrated above Bangladesh is the one of such place for
the purpose.
6. Anti mosquito measures available –Effective anti mosquito measures are
very important for the contamination of the disease. It can be segmented as
follows-
• Fuming
• Liquidator
• Mosquito mat
• Mosquito net
• Repellents
• No measures

7. Facilitate proliferation to vectors- It is determined by the available
containers for the facilitation of the breeding of the vector mosquitoes.
These places includes-
• Plastic drum
• Cemented tank
• Discarded tire
• Flower pot/base
• Coconut shells
• Tree holes
• Metal drum
• Mud pot
• Plastic bottle
• Plastic pot
• Unused bucket
• Brick clefts
• miscellaneous
8. Population density
9. Migration

ECONOMIC BURDEN
According to a middle class health care center (Japan Bangladesh Friendship
Hospital) we have collected the pricing list of the diagnostic tests. From that
on we can calculate a general expenditure of the diagnostic tests done for the
identification of the ‘Chikungunya’.
1. TC,DC,HB%,ESR – 350 tk
2. Platelet count – 200 tk
3. Total eosinofil count – 200 tk
4. Bleeding time – 100 tk
5. Clotting time – 100 tk
6. SGPT – 300 tk
7. Anti – HEV IgM – 1000 tk
Each time this diagnostic tests takes at lest 2000 taka (BDT). So as a whole for
two times it takes at least 4000 taka. Along with that the price of medicine,
transportation expenditure to the health care center, cost of hospitalization,
nutritious food and a constant care giver for the patient causes a significant
amount of resources consist of time and money. For a patient with prevailing
illness, the treatment becomes more costly and critical also. So it is important
to prevent the disease as early as possible to stop this money drain of the
poor people.

Chikungunya - An Emerging Threat to Bangladesh by Dr. Syeda Zerin Imam

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