cestodes recent advances

1. RECENT ADVANCES IN
DIAGNOSIS OF CESTODES

2. Cestodes - long, segmented, tape like worms - tapeworms.
• classified into two groups:
 1. Intestinal cestodes 2. Somatic/tissue cestodes
 Tenia saginata Taenia solium
 Tenia solium Echinococcus
 Diphyllobothrium species Spirometra species
 Hymenolepsis
 Dipylidium

3. DIPHYLLOBOTHRIUM SPECIES (FISH TAPE WORM)
• Sample – stool sample
• Microscopy – identification of characteristic eggs / proglottid segments
• Molecular (research purpose only) RFLP – species determination/
epidemiological studies
PCR – in stool samples following sonication of eggs to release its
contents
Radiography – following a contrast gastrografin

4. SPIROMETRA SPECIES
Sample – biopsy of nodule , blood
demonstration of the larva
Serology – ELISA – IgG antibodies (10–12 days post infection )
detection of cysteine protease ( excretory-secretory proteins) - early antigen identification
PCR – using species specific mitochondrial genome sequence
CT or MRI scans - identify spargana larvae in other areas of the body, like the brain.

5. TAENIA SAGINATA
Sample – stool sample
Microscopy – characteristic eggs and proglottids
Antigen detection – ELSIA – polyclonal Teania antibodies(treatment followup)
PCR -detection of ribosomal 5.8S gene

6. TEANIA SOLIUM
Sample – stool sample, serum, CSF,biopsy of brain , subcutaneous tissue etc
FNAC of cyst
Microscopy – characteristic eggs and proglottids
Antigen detection – ELSIA – monoclonal Teania solium antibodies(treatment followup)
Antibody detection – ELISA (quantitative ) – using T24H recombinant antigen
ELISA employing TsM CF as an antigen
Westernblot(enzyme immune transfer blot )- using lentil lectin purified glycoprotein
Histopathology – cysticerci detected in muscles , eye , brain ( during postmortem)
Multiplex PCR
LAMP - targeting the mitochondrial cytochrome c oxidase subunit 1 (cox1)

7. • Recombinase polymerase amplification (RPA)- to detect DNA/RNA
• MRI of brain- visualization of the parasitic scolex

8. ECHINOCOCCUS SPECIES
Sample- hydatid fluid, serum
Microscopy – brood capsule / protoscolises
H&E stain – cyst wall and attached brood capsules
Serology-(Antibody detection) ELISA – Recombinant B2t /2B2t antigen
DIGFA – dot immunogold filteration assay
immunoblot (westernblot)- h-HCF-IB – using human hydatid cystfluid antigen
(confirmatory test)
PCR- RFLP – target mitochondrial DNA

9. • Imaging – Xray – calcified cysts / hepatomegaly
USG(method of choice)-
CT/MRI – snowflake/ water lily sign
fluorodeoxyglucose-positron emission tomography (FDG-PET)

10. HYMENOLEPSIS NANA
Sample- stool sample, tissue biopsy
Microscopy - non bile stained agg with polar filament
Immunohistochemistry -Digoxigenin-labeled DNA probes targeting a 206-bp fragment of the H. nana 18S
rRNA gene
PCR-amplification of the rDNA ITS2 region
GENOMIC SEQUENCING AND COMPARATIVE ANALYSIS