This document summarizes several emerging viral diseases seen in Kerala, India. It discusses the causative agents, modes of transmission, signs and symptoms, diagnosis, treatment and prevention measures for diseases such as chikungunya, Japanese encephalitis, West Nile virus, dengue fever, H1N1 influenza, hepatitis E, and hand, foot and mouth disease. It also provides information on viruses such as hantavirus, flaviviruses and techniques for laboratory diagnosis and immunization against certain diseases.

1. EMERGING VIRAL DISEASES IN
KERALA

2. ARBOVIRUSES:
Dengue
Chikungunya
Kyasanur Forest Disease
Japanese encephalitis
 West Nile virus
Robovirus
 Hantavirus

3. Hepatitis E
Influenza (H1N1)
Measles
Viral Diarrhoea
Hand Foot and Mouth Disease

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Chikungunya…..
It is a viral fever caused by an Alpha virus
-Epidemiology:
-Mode of transmission-Through bites from
Aedes aegypti mosquitoes.
-During June 2007,out breaks were reported
from Pattanamthitta,Kottayam & Alappuzha
districts of south Kerala.

5. Morphology
 Spherical enveloped virus.
 Size: 50-70 nm diameter.
 Genome is a molecule of single stranded
RNA.
 Replication – is in the host cell cytoplasm
and released by budding.

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-
1. Fever-typically’ biphasic’
2.Petechial or maculopapular rashes-involving
limbs and trunks.
3.Joint pain-Patient lies “doubled up”due to
severe joint pains
4.Lymphadenopathy
5.Conjunctivitis
Symptoms:
 Incubation period – 5 days (3-7 days).

7. Diagnosis
 Serodiagnosis is the main approach.
 ELISA for IgM or IgG antibodies in paired
serum sample.
 PCR- detects viral RNA.

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Continuation….
Treatment:
-No specific treatment.
-No vaccine currently available.
Preventive measures:
-Protect against any contact with disease
carrying mosquitoes,using insect repellents.

9. Flavivirus
Mosquito borne group:
1. Japanese encephalitis virus.
2. Dengue virus.
3. Yellow fever virus.
Tick borne group:
1. Kayasanur forest disease

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Japanese encephalitis…
 Principal vector: Culex mosquito
 Clinical manifestations:
 Incubation period: 5-15 days.
 Abrupt onset with fever,head ache and
vomiting.
 Signs of encephalitis with nuchal rigidity.
 Convulsions.
 Altered sensorium.
 Coma.

11.  Mortality rates in some epidemics has been
upto 50%.
 Convalesence takes many weeks.
 Large majority of infections are
asymptomatic.

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Clinical findings:
 Neutrophil leucocytosis.
 normal or raised sugar.
 Slightly raised protein in CSF.
 Reservoir host:Herons.
 Amplifier host:Pigs.
 Preventive measures:
 Mosquito control
 Locating piggeries away from the human
dwellings.

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Immunization programme…
-A formalin inactivated mouse brain vaccine
using the Nakayama strain.
- Beijing-3 strain - inactivated
-JE strain SA14-14-2 – a live attenuated
vaccine.
- IC51 – Australian – Vero cell -
Whole cell – formalin inactivated

14. West Nile Virus
Reported in Kerala in May 2011
WNV infection is primarily maintained in
nature in a cycle between birds and
mosquitoes (usually Culex).
 Transmitted during blood meals by
mosquitoes to man and horses (dead end
hosts)
 Cases of man-man transmission after solid
organ transplantation or blood transfusions

15. WNV infection is usually asymptomatic or results in a
non-specific viral fever.
 Fewer than 1% of the cases develop neuroinvasive WNV
infection, often a non-specific meningoencephalitis
Acute flaccid paralysis can occur
Reversible paralysis
 Hepatitis, pancreatitis, myocarditis, nephritis, optic
neuritis and cardiac dysrhythmias and hemorrhagic fever
with coagulopathy
 Rash

16. Laboratory Diagnosis
 Virus is rapidly cleared from blood within 2 days of onset of illness.
Hence, PCR and real-time PCR are positive only for 2-3 days
 The main stay of diagnosis of WNV encephalitis is antibody
detection in serum or CSF
 The high level of cross reactivity between WNV and JEV makes
the differentiation by IgM capture ELISA difficult.
 Demonstration of significantly high level of virus specific
neutralizing antibodies
 Fourfold rise in titer in the patient serum/CSF by micro-
neuralization assay or plaque reduction neutralization test assay

17. Treatment
Supportive measures

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Dengue fever…
-Another term-Break-bone fever.
-Causative agent –Dengue virus
- types-4 types DEN 1-4.
- More than 7000 cases in kerala in 2016 and 13
deaths
-Clinical manifestations-
-Incubation period-3-14 days.
-Symptoms:
a)Sudden onset of fever with headache.
b)Retrobulbar pain
c)Conjunctival injection

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Continuation…
d)Pain in the back and limbs(Break-bone
fever).
e)Lymphadenopathy
f)Maculopapular rash
-Fever is typically biphasic & last for 5-7
days.
-Most serious forms:
-Dengue hemorrhagic fever (hemorrhagic
manifestations)
-Dengue Shock syndrome.(Shock).

20. Pathogenesis
 Primary dengue infection- when a person
is infected with dengue for the first time.
 Secondary dengue infection- months to
years later a severe form of dengue illness
appears due to infection with another
serotype.
 Infection leads to formation of neutralizing
and non-neutralizing antibodies.

21.  Neutralizing antibodies- protective against
infecting serotype and other serotypes.
 Non-neutralizing antibodies- protective
against only other serotypes.

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Continuation…
-Vector-Aedes aegypti mosquitoes.
Laboratory diagnosis:
-Demonstration of antibody by ELISA.
-Strip immunochromatographic test for IgM
is available for rapid diagnosis.
- RT-PCR , real time PCR for viral RNA
Control:
-Vector control.
-No vaccine is currently available in India.

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Tick-borne hemorrhagic fever
1.Kyasanur Forest Disease (KFD)
-Hemorrhagic fever that occurs in
Karnataka state.
- In 2015, 102 cases and 11 deaths in kerala
- In 2016, 9 cases

24.  Reservoir host-Forest birds and mammals.
 Vector – ticks ( Haemophysalis spinigera).
 Mode of transmission-Bite of ticks
 In monkeys it causes fatal disease.
Clinical manifestations in humans
-Incubation period 3-8 days.
-Sudden onset with fever,headache,conjunctivitis
and severe prostration.
-Some cases develop hemorrhages.
- Neurological manifestations - headache, neck
stiffness, altered sensorium, seizures, visual
deficits

25. Diagnosis
 RT-PCR within 5 days of onset
 After 5 days, IgM antibody detection by
ELISA.

26. Vaccine
 A formalin inactivated chick embryo
vaccine has been developed at Haffkine
institute Mumbai.

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Hantavirus:
Family Bunyaviridae
Causes Haemorrhagic Fever with Renal
Syndrome (HFRS)
Causes Hantavirus Pulmonary
Sundrome
Inhalation of aerosolised rodent
secretions, urine or faeces containing
virus

28. Hantavirus
- Single stranded RNA virus, negative sense
- 120- 160 nm , enveloped
HFRS:
- Incubation period- 1 to 2 weeks
- Prodromal symptoms- fever, fatigue,
myalgia
- Followed by hypotension, oliguria, renal
failure, proteinuria

29. Hantavirus Pulmonary
Syndrome
Prodromal symptoms- fever, cough,
myalgia, headache, lethargy
 Dyspnoea, acute respiratory failure,
pulmonary edema
Mortality about 40%

30. Laboratory Diagnosis
- IgG ELISA demonstrating fourfold rise in
titre in paired sera
- IgM ELISA
- RT-PCR

31. Treatment
No cure or vaccine available
Supportive treatment – dialysis,
mechanical ventilation
Ribavirin
Rodent control measures

32. Hepatitis E
 Positive-sense RNA virus
 Hepevirus
 4 genotypes
 Feco-oral transmission through water/
food
 After monsoon
Reservoir : pigs, boar, chicken, deer

33. - HEV is the commonest cause of viral hepatitis in
this area
- No vaccine available in India
- Self-limiting illness
- 4 genotypes – 1and 2 in humans, 3 and 4 also in
animals. Only one serotype.
- Mortality less than 1%
- In pregnancy, more than 25%

34. Clinical features
• Incubation period – 2 to 6 weeks
• Acute infection- jaundice, dark urine,
fatigue, nausea, vomiting and abdominal
pain.
• Fulminant hepatitis – 1% -4%
• Greater in pregnancy

35. Laboratory diagnosis
- Stool, serum samples
- ELISA for IgM in serum
- HEV RNA by RT-PCR in serum or stool
- Prevention by improved sanitation

36. Hand, foot and Mouth Disease
01/09/15
-Occurs mainly in children. Can occur in
adults
- Oral and pharyngeal ulceration and rashes
of palms and soles, gluteal region.
-fever
-Coxsackie virus A16, enterovirus 71 mainly
- Occasionally by Coxsackievirus A4-A7,
A9, A10, B1-B3, and B5

37. - Mostly self-limiting
- Enterovirus 71 may be associated with
neurological complications
- Aseptic meningitis, encephalitis, rarely
flaccid paralysis

38. Transmission
- Transmitted by nasopharyngeal secretions
by direct contact, or by fecal-oral
transmission.

39. Laboratory diagnosis
-RT-PCR for viral RNA from throat swab or
from stool samples
- Mostly clinical diagnosis
- No vaccine available in India
-Handwashing, quarantine of affected
children

40. Influenza (H1N1)
- Pandemic in 2009
-Genetic reassortment of influenza strains in
pigs – 1 human, 2 swine, 1 avian

41. Symptoms
Fever > 100 deg F,
- Upper respiratory symptoms
- Cough
- Sore throat.
- Head ache, bodyache, fatigue, diarrhea and
vomiting

42. Category- A,B&C
Category A- mild fever plus cough / sore
throat with or without body ache,
headache, diarrhoea and vomiting
Category-B (Bi) Category-A plus high grade
fever and severe sore throat
(Bii)
 Pregnant women
 Lung/ heart / liver/ kidney / neurological
disease, blood disorders/

43. Category C
· Breathlessness, chest pain, drowsiness, fall
in blood pressure, haemoptysis, cyanosis
· Children with red flag signs:
. Somnolence, high/persistent fever, inability
to feed well, convulsions, respiratory
distress
· Worsening of underlying chronic
conditions.

44. H1N1 Testing
Cat- A- No testing needed
Cat-B- No testing for Category-B (i) and (ii)
Cat-C- Test may be needed, but do not wait
for test results
Specimen required - 1 throat swab and 1
nasal swab, using Dacron swab, and
immersed in Viral Transport Medium tube,
refrigerated at 2-8 deg C .

45. Testing centres
3 authorized testing centres for Kerala,
1. Rajiv Gandhi Centre for Biotechnology,
Thiruvananthapuram,
2.Virology Division, KMC Hospital,
Manipal, Karnataka State.
3. NIV Unit, Medical College, Alappuzha

46. Management:
No Oseltamivir
--Symptomatic treatment
--Good supportive measures
 Plenty of warm nourishing oral fluids,
 Good food intake
 Complete rest
--Monitor progress and reassess at 24 to 48 hours.
Self isolation at home, and telephone follow up for the next
2-3 days
--Any suggestion of deterioration/ failure to improve?--
report in person stat

47. Category-B
(Bi) Home isolation
---Oseltamivir to be started
(Bii) Start Oseltamivir immediately
--Self isolation at home, and telephone
follow up for the next 2-3 days
--Any suggestion of deterioration/ failure to
improve?- report in person stat

48. Category C

Hospitalization stat

Start Oseltamivir immediately, without
waiting for test results

Intensive supportive management is
usually necessary.
H1N1 in Pregnancy (Ante natal and early
Post natal)

Pregnancy is an extreme high risk
category

49. Oseltamivir dosage schedule

For weight <15kg - 30 mg BD for 5 days

15-23kg - 45 mg BD for 5 days

24-<40kg -60 mg BD for 5 days

>40kg -75 mg BD for 5 days

50. Chemoprophylaxis
For those with high risk Eg. pregnancy/
diabetes/ Asthma/immunosuppressed/
- Start OD dose Oseltamivir x 10 days

51. Vaccines
-Inactivated vaccines
- Live attenuated cold adapted vaccines

52. Inactivated vaccines
- Grown in allantoic cavity of embryonated
egg
- Protectiveness 50-80%. Lasts up to 1 year
-Administered im/sc
3 types
- Whole virus
- Subvirion
- Surface antigen – NA,HA

53. Live attenuated vaccines
- Trivalent vaccine – 2 circulating type A
and a type B
- Cold adapted – grow at 33 deg C but not at
37 deg C
- Given as intranasal spray
- Do not infect lower respiratory tract
- Not given in pregnancy and high risk
groups

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