Blood & Tissue Nematodes
SUBCUTANEOUS
- Loa loa
- Mansonella streptocerca
- Onchocerca volvulus
SEROUS CAVITY
- Mansonella spp.
LYMPHATIC
- Wuchereria bancrofti
- Brugia malayi
| W. bancrofti | B. malayi | |
| Mean length (um) | 290 | 222 |
| Cephalic space: breadth | 1:1 | 2:1 |
| Sheath in giemsa | Unstained | Pink |
| Nuclei | Regularly spaced; separate | Irregularly spaced; overlapping |
| Tail | Single row of nuclei; does not reach tail end | Single row of nuclei reaches the tail |
| Terminal nuclei | NONE | 2 nuclei; bulge at cuticle |
| Appearance in blood film | Smoothly curved | Kinky |
| Filarial worm | Periodicity | Diagnostic test | Interediate host | Specimen | Microfilariae |
| W. bancrofti | Nocturnal (8 pm – 4 am) | Microfilariae | Culex, Aedes, Anopheles | Blood | Sheathed; absent nuclei at tail |
| B. malayi | Nocturnal | Microfilariae | Anopheles, Mansonia | Blood | Sheathed, 2 separate nuclei at tail |
| Loa loa | Diurnal | Microfilarie | Chrysops fly, tabanid or mango fly | Blood | Sheathed, nuclei continuous up to the tip of the tail. |
| O. volvulus | None | Adult worm in excised tissue | Simulium (black fly) | Skin snips | NO SHEATH |
Parastrongylus cantonensis
- Rat lungworm
- Barber’s pole pattern – spiral arrangement of uterine tubules
- DEFINITIVE HOST – RATS
- INTERMEDIATE HOSTS IN MOLLUSC – 1ST LARVA STAGE
- INTERMEDIATE HOST – SLUGS & SNAILS
- MODE OF TRANSMISSION – Ingestion or penetration
- INTERMEDIATE HOST IN HUMANS – 3RD STAGE LARVA
- MODE OF TRANSMISSION (HUMANS)
- Ingestion of raw mollusk
- Ingestion of contaminated food
- Ingestion of paratenic host
- Drinking contaminated water
DIAGNOSIS
- DOT-BLOT ELISA
- Immuno-PCR detection
TREATMENT
- Surgical removal
- Prednisone
Trichinella spiralis
- INFECTIVE STAGE: ENCYSTED LARVA IN STRIATED MUSCLE
- MODE OF TRANSMISSION: INGESTION OF UNDERCOOKED OR RAW MEAT
PATHOLOGY & CLINICAL MANIFESTATION
- Stages
- ENTERIC – invasion of intestine and incubation
- INVASION – larval migration and intestinal invasion
- CONVALESCENT – encystment and encapsulation
- DIAGNOSIS
- Muscle
- Biopsy
- ELISA
- Latex Agglutination
- Bachmann Intradermal Test
- TREATMENT
- Mebendazole
- Albendazole
PREVENTION AND CONTROL
- Cook meat at minimum of 77°C
- FREEZING o -15°C for 20 days o – 30°C for 6 days
Anisakis
- Parasite of marine animals
- INFECTIVE STAGE – 3RD STAGE LARVA
- MODE OF TRANSMISSION – INGESTION OF UNDERCOOKED OR RAW SQUID OR FISH
DIAGNOSIS
- Gastroscopic / endoscopic exam
- ELISA
- RAST
TREATMENT
- Mechanically remove larva using endoscopic forceps
CONTROL & PREVENTION
- Freezing
Dracunculus medinensis
- Longest nematode of man
- “guinea worm”, “fiery serpent worm”
- INFECTIVE STAGE – INFECTIVE LARVAE
- MODE OF TRANSMISSION – INGESTION OF CONTAMINATED CRUSTACEANS
- INTERMEDIATE HOST – AQUATIC CRUSTACEANS (COPEPODS / CYCLOPS)
Toxocara canis & Toxocara cati
- Clinical forms of Toxocariasis
- Visceral Larva Migrans (VLM)
- Ocular Larva Migrans
- Covert Toxocariasis
DIAGNOSIS
- Tissue biopsy
- IgG ELISA
- Western blot
- PCR
TREATMENT
- Albendazole
- Mebendazole w/ anti-inflammatory drugs
