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python -m markitdown "/home/daytona/workspace/attachments/9721b721-2f8f-4723-9e13-6d73679c411f/ldvi .pptx"

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cd /home/daytona/skills/pptx && ls scripts/

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python /home/daytona/skills/pptx/scripts/office/unpack.py "/home/daytona/workspace/attachments/9721b721-2f8f-4723-9e13-6d73679c411f/ldvi .pptx" /home/daytona/workspace/ldvi_unpacked/

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unzip -o "/home/daytona/workspace/attachments/9721b721-2f8f-4723-9e13-6d73679c411f/ldvi .pptx" -d /home/daytona/workspace/ldvi_unpacked/ 2>&1 | head -50

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ls /home/daytona/workspace/ldvi_unpacked/ppt/slides/ | head -30

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python3 -c " import os, glob from xml.etree import ElementTree as ET ns = {'a': 'http://schemas.openxmlformats.org/drawingml/2006/main', 'p': 'http://schemas.openxmlformats.org/presentationml/2006/main', 'r': 'http://schemas.openxmlformats.org/officeDocument/2006/relationships'} slides_dir = '/home/daytona/workspace/ldvi_unpacked/ppt/slides' slide_files = sorted(glob.glob(os.path.join(slides_dir, 'slide*.xml')), key=lambda x: int(''.join(filter(str.isdigit, os.path.basename(x))))) for sf in slide_files: tree = ET.parse(sf) root = tree.getroot() texts = [] for t in root.iter('{http://schemas.openxmlformats.org/drawingml/2006/main}t'): if t.text and t.text.strip(): texts.append(t.text.strip()) slide_num = os.path.basename(sf).replace('slide','').replace('.xml','') if texts: print(f'--- Slide {slide_num} ---') print(' | '.join(texts)) print() "

This is a microbiology lecture by Dr. Bijendra Raj Raghubanshi (Professor, Dept. of Microbiology) titled "Laboratory Diagnosis of Viral Infection". Here's a full breakdown:

Overview

The presentation covers how laboratories identify viral infections — from specimen collection all the way to molecular techniques like PCR.

1. Specimen Collection & Transport

Specimens vary by infection type: nasal wash, throat swab, stool, CSF, urine, blood, etc.
Must be collected early in the acute phase and processed immediately
If delayed: store on ice (4°C) or freeze at −20°C or below
Transported in Stuart's viral transport media

2. Five Main Laboratory Methods

I. Microscopy

a. Electron Microscopy (EM)

Directly visualizes virus particles
Mainly used for viral gastroenteritis: rotavirus, adenovirus, astrovirus, calicivirus, Norwalk-like viruses
Immune EM uses virus-specific antibodies to agglutinate particles — but it's expensive and has poor sensitivity

b. Antigen Detection

Immunofluorescence testing
Rapid immunochromatographic tests (e.g., rapid antigen tests)

c. Cytopathology (Light Microscopy)

Looks for cellular changes caused by virus replication:
- Syncytium formation, cell necrosis/lysis, cellular clumping
- Inclusion bodies — virus-specific intracellular masses (~20–25 µm) with distinct size, shape, location, and staining
  - Intracytoplasmic: Negri bodies (rabies), Guarnieri bodies (smallpox), Bollinger bodies (fowl pox)
  - Intranuclear: Cowdry A (herpes, yellow fever), Cowdry B (adenovirus, poliovirus)

II. Isolation & Identification

Three systems used to grow viruses:

a. Laboratory Animals

White mice and chimpanzees
Suckling mice (<48 hours old): susceptible to togaviruses and coxsackieviruses

b. Chick Embryo (7–12 days old)

Chorioallantoic membrane (CAM): grows poxvirus → produces visible pocks
Allantoic cavity: mainly for vaccine production
Amniotic sac: isolation of influenza virus
Yolk sac: some viruses + intracellular bacteria (Chlamydiae, Rickettsiae)

c. Tissue Culture

Types: organ culture, explant culture, cell culture
Cell culture subtypes:
- Primary (monkey kidney, human amniotic cells)
- Diploid (embryonic fibroblasts)
- Continuous (HeLa, Hep-2, KB cells)
Viruses identified in culture by: electron microscopy, neutralization, haemadsorption/haemagglutination, cytopathic effects (CPE), immunofluorescence

III. Serology

Used to detect antibodies in patient serum. Paired sera (acute + convalescent) showing a 4-fold rise in antibody titre confirms recent infection.

Test	What It Detects
Haemagglutination inhibition (HI)	Antibodies to viral haemagglutinin
Complement fixation test (CFT)	Complement-fixing antibodies
Immunofluorescence	Using fluorescein-conjugated antiserum
Neutralisation	Virus-neutralizing antibodies
ELISA	Antibodies via enzyme-labelled anti-human Ig
Western blot	Confirmatory test (historically for HIV)

IV. Detection of Viral Particles

Mentioned as a category but covered under microscopy (EM above).

V. Molecular Methods

Nucleic Acid Probes / DNA Probes

Useful for slowly replicating viruses

PCR (Polymerase Chain Reaction)

Invented in 1983 by Kary B. Mullis
Amplifies millions to billions of copies of a specific DNA segment
Three steps: Denaturation → Primer Annealing → Extension (using heat-resistant Taq polymerase in a thermocycler)
RT-PCR: RNA first converted to DNA (cDNA), then amplified — used for RNA viruses
Real-time PCR (qPCR): quantifies viral load

Summary Table

Method	Examples
EM	Rotavirus, Norwalk virus
Antigen detection	Flu rapid tests, immunofluorescence
Inclusion bodies	Negri (rabies), Guarnieri (smallpox)
Lab animals	Suckling mice (coxsackievirus)
Chick embryo	Influenza, poxvirus
Tissue culture	HeLa cells, CPE observation
Serology	ELISA, Western blot, HI test
PCR / RT-PCR / qPCR	HIV, influenza, most modern diagnostics

The lecture flows logically from sample collection → direct detection → culture → antibody tests → molecular methods, covering both classical and modern virology diagnostics.

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