New presentation on same title, improved contents

1. Syndromic approach in
Diagnostic virology

2. What we discus here?
• Why do syndromic approach?
• Different types of syndromes
• One syndrome - related viral infection

3. Why do syndromic approach?
• No technique – identify broad group of viral
pathogen.. Like Bacterial culture
• Numerous pathogenic viruses

4. Syndrome
• A syndrome is a set of medical signs and
symptoms that are correlated with each other
and, often, with a specific disease.
• There is no single step diagnostic procedure in
viral disease – we rule out a viral disease in
syndrome based testing.

5. Major clinical syndromes related to
viral infection
1.Fever of unknown origin
2. Influenza like illness (ILI)
3. Severe acute respiratory illness (SARI)
4. Acute respiratory distress syndrome (ARDS)
5. Dengue like illness DLI (fever +myalgia)
6. Fever + Arthralgia
7. Fever + rash(measles like)

6. 8. Acute encephalitis syndrome(AES)
9. Fever + Parotitis (mumps like)
10. Acute jaundice syndrome (AJS)
11. Acute diarrhoea syndrome (ADS)
12. Acute hemorrhagic fever syndrome (AHFS)
13. Syndromes with conjunctivitis
Syndromes

7. Diagnostic Approach
• Test to be done is choose based on an algorithm
by a panel after thorough discussion.
• Following factors are observed
1. Age of patients.
2. All presenting clinical symptoms
3. History/Job/Travel etc..
4. Season
5. Epidemiological factors
6. Any other relevant information
7. Cause suspected by Clinician also checked.
8. Very detailed request form.

8. Examples

9. Fever of unknown origin
• Diagnostic challenge
• Fever may be due to many reason
• Bacteraemia/Sepsis
• Secondary to a focal infection
• Any non specific presentation of a disease
• Parasitic, Fungal infection
• Viral _ Diagnosis is very difficult.

10. Diagnostic steps- FUO
• Blood/Serum
• Most of FUO are bacterial.
• Leptospira/Scrub typhus
• Dengue – IgM detection by ELISA

11. INFLUENZA LIKE ILLNESS (ILI)
Case Definition: Sudden onset of fever>100 0F
with
• Cough and or/sore throat AND
• An absence of other diagnosis

12. Severe Acute Respiratory Illness (SARI)
Case definition
• for persons > 5years - Sudden onset of fever, and
Cough or sore throat, AND Shortness of
breath/difficulty in breathing
OR
• Any child <5yrs old clinically suspected of
having pneumonia or severe /very severe
pneumonia

13. Causes of ILI & SARI

14. Acute Respiratory Distress Syndrome
(ARDS)
• Acute respiratory distress syndrome (ARDS)
occurs when fluid builds up in the air sacs
(alveoli) of lungs. less oxygen can reach
bloodstream.
• Acuteonset
• PaO2 /FiO2 (fraction of inspired oxygen)
<200mmHg.
• X-ray bilateral infiltrates.
• Pulmonary arterial occlusion.

15. ARDS causing agents

16. Diagnostic Approach to ILI, SARI and ARDS
• Syndrome is classified into two classes.
• More symptoms seen in URT eg: ILI
• More symptoms seen in LRT eg: SARI & ARDS
Sample URT – Throat swab – Ideal
• Nasopharyngeal swab – Ventilator patient
Sample LRT – ET Aspirate, Bronchial Washing/BAL
Blood – For rule out other cause. Eg: Dengue mimic
ILI – IgM dengue can be detected.

17. Testing pattern
• Throat swab/Respiratory specimen
 PCR for Influenza A and B and sub typing by PCR
 If patient 6 months – 1 year age RSV – PCR then InfV A&B PCR
 if negative, PCR for adenoV, RhV, coronaV, enteroV, RSV, hMPV,
parainfluenza virus.
 Multiplex PCR – panel available: Kit.
 Blood sample: Rule out Dengue/Lepto mimicry-IgM detection
 ImmunoFlu : possible but not usually employed in diagnosis.
? Any bacterial or other cause?

18. DLI(fever+myalgia)
Definition:
• A diagnosis of DLI is established on the basis
of clinical features and supporting non
serologic laboratory investigations
•With negative /incomplete serologic testing
can be included

19. Conditions that mimic febrile phase of
dengue viral infection
FLU LIKE
SYNDROMES
FEVER WITH DIARRHEA
RASH
Iillnesses with
Neurological
manifestations
Others
INFLUENZA
CHIKUNGUNYA
HIV
(seroconversion
state)
Rubella
Measles
Chikungunya
Drug reactions
Meningococcal
infection
Rota virus
other
enteric
infections
causes of
meningoencephalitis
Febrile seizures
Leptospirosis
Rickettsial
infection
Enteric fever
Malaria
Viral hepatitis
Brucellosis

20. Conditions that mimic critical phase
Bacterial Viral Parasitic
Leptospirosis
Rickettsial infections
Acute gastero enteritis
Typhoid
Bacterial sepsis
Septic shock
Viral hepatitis
Other causes of Viral
hemorrhagic fevers like
Kayasanur forest
disease ,Crimean congo
hemorrhagic fever
Malaria
Others-
acute leukemia
-other malignancies
-other causes of acute
abdomen
-platelet disorders

21. Diagnostic approach to DLI
• Sample : Blood
• IgM ELISA – Dengue, CHIK V, Leptospira,
• Dengue NS1 ELISA
• KFD PCR
• IgG ELISA _ Dengue- Second infection
? Any other cause further studied.

23. Diagnostic approach – Fever with
arthralgia
• Sample: Blood
• IgM ELISA: Chikungunya, Dengue, Lepto.
• KFD - PCR

24. Fever with rash (measles like illness)
rash is an area of skin that has become redden/swollen/irritated

25. Diagnostic approach – fever with rash
Maculo – papular rash
• Sample: blood, Throat swab
• IgM ELISA – Dengue, Measles, Corona,
Rubella, Any seasonal/endemic pathogen.
• Throat swab – PCR for measles, rubella,
enteroV, coronaV, ParvoV, KFD (season)
• IgM – ELISA - HHV 6/7, CHIK V.

26. Diagnostic approach.. continues
Vesicular rash
Location of vesicle, age, geographic area are
important
Eg: HSV 1 facial/HSV 2 genital
• Blood : HSV and VZV IgM - ELISA
• Vesicle swab : PCR for – HSV 1&2, VZV, HFMD
Virus

27. Fever with parotitis (mumps like infection)

28. Fever with parotitis – Diagnosis
• Sample: Blood, Salive, Urine, CSF
• Blood: IgM mumps
• Other samples: PCR – both monoplex and
multiplex PCR
• Eg: Saliva PCR for mumps, parainfluenza, EBV,
Coxsackie virus, AdenoV parvo, HIV.
• PCR in Urine and CSF – Positive in many cases.
Eg: mumps.

29. Acute encephalitis syndrome(AES)
Definition
• A person of any age, at any time of the year with
acute onset of fever, a change in mental status
(confusion, disorientation, coma, inability to talk)
AND/OR
New onset seizures(excluding simple febrile
seizure)

30. Acute encephalitis syndrome causing
agents

31. AES in immunocompromised

32. AES - Diagnosis
• CSF
• Blood
CSF – IgM ELISA – JE and WNF.
CSF – PCR for HSV 1&2, VZV, enteroV, other
suspected pathogen based on patient history
age,seson etc..
Blood: IgM ELISA - Dengue, Lepto, Scrub, and
other suspected pathogen based on patient
history age etc..
PCR with blood for KFD

33. Acute Jaundice syndrome
• Definition :acute onset of jaundice and severe illness
AND
• Absence of known predisposing factors

34. Causes acute Jaundice syndrome

35. Diagnosis - AJS
• Sample: Blood
• HBsAg Detection By ELISA
• IgM ELISA – HAV and HEV
• IgM/IgG ELISA for HCV
• Leptospira IgM

36. Acute Diarrhea Syndrome
• Definition :Acute diarrhea and severe illness
AND
absence of known predisposing factors
•Diarrhea:Increased frequency of defecation or recent
change in consistency and character of stools
•If lasts more than 3 weeks it is known as chronic
diarrhea .
Viral infections cause watery diarrhea

37. Causes of watery diarrhoea

38. Diagnosis _ ADS
• Sample: Stool, Rectal swab
PCR_ Ist line: Rota, Noro, Adeno, Astro.
_ second line: Corona, Entero, any other
suspicious
Stool sample: Rota Ag ELISA
• Blood: Dengue, Lepto IgM ELISA

39. Acute hemorrhagic fever syndrome
DEFINITION: Acute onset of fever of less than 3 weeks
duration And any two of the following.
• Hemorrhagic or purpuric rash
• Epistaxis (bleeding from nose)
• Hemoptysis (coughing up of blood)
• Blood in stool
• Other hemorrhagic symptoms
AND
• absence of known predisposing factors

44. Diagnosis - AHFS
• Sample: Blood
Geographic location/Travel history….
• ELISA for IgM/(IgG secondary infection as in
case of DHF)
• Dengue, KFD, YF, Hunta
• Lepto, Malaria, Rickettsial
• PCR in Blood

45. Syndromes with conjunctivitis

48. Acute hemorrhagic conjunctivitis
• Complication of
conjunctivitis
• Enterovirus, CoxsackieA24,
A24v
• Diffuse patchy conjunctival
haemorrhage
• Hemorrhagic patches
diffusely distribute in the
bulbar conjunctiva -3 days
after onset

49. Complication of AHC
• Moderate epithelial
keratitis and conj.
hyperaemia

50. Diagnosis of syndromes with
conjunctivitis
• Sample: Conjunctival swab, Corneal impression
smear, Blood
• Monoplex and Multipples PCR – Swab
• Direct immuno fluorescence – Smear
• IgM against virus detection: Blood

51. Comment: Many other techniques like
culture, Animal inoculation, Direct and
indirect immuno fluorescence, HA,
HIA, VNA are not employed as a
diagnostic technique - since are not
reliable
Nowadays lab diagnosis of Viral
infection is greatly depended on PCR
and ELISA