Nematodes
Characteristics
- Cylindrical, elongated, & bilaterally symmetrical
- Anterior end equipped with hook, teeth, plates and papillae
- Alimentary tract is simple, extending from mouth to anus. NO CIRCULATORY SYSTEM
UNHOLY THREE
|
HEART-LUNG MIGRATION
|
SMALL INTESTINE
|
LARGE INTESTINE
|
Ascaris lumbricoides
- Largest intestinal worm
- Anterior end has 3 lips and triangular buccal cavity with sensory papillae
- INFECTIVE STAGE – EMBRYONATED EGGS
- MODE OF TRANSMISSION – INGESTION
- DIAGNOSIS – (+) EGG IN THE FECES
PATHOLOGY & MANIFESTATION
- “worm ball” / bolus formation in heavy infection
- Ascaris pneumonitis
- Eosinophilia
- Abdominal pain
- Loeffler’s syndrome
VECTORS
- Periplaneta Americana
- Blatella germanica
TREATMENT
- Benzimidazole
- Pyrantel pamoatehiura
Trichuris trichiura
- Whipworm; holomyrian
- Anterior resembles “string of beads”
- Adult worm inhabits the cecum and colon
- INFECTIVE STAGE – EMBRYONATED EGG (lemon/football shaped) “Japanese lantern”
- MODE OF TRANSMISSION – INGESTION
PATHOLOGY & CLINICAL MANIFESTATION
- Petechial hemorrhage – may predispose amebic dysentery ulcers and invasion of E. histolytica
- Cause anemia
- Rectal prolapse
- Adult worm produces pore-forming protein caplled TT47
TREATMENT
- Mebendazole
- Albendazole
HOOKWORMS: Necator americanus & Ancylostoma duodenale
- INFECTIVE STAGE – FILARIFORM LARVAE
- MODE OF TRANSMISSION – SKIN PENETRATION
- Egg – resembles MORULA BALL
PATHOLOGY AND CLINICAL PRESENTATION
- Mazza mora, ground itch, dew itch, water sore
- Wakana Disease
- Iron Deficiency Anemia
- Hypoalbuminemia
| A. Duodenale | N. americanus | |
| Position of the head | Anterior head continuous in the same curve as the body | Anterior and strongly reflexed dorsally |
| Buccal cavity | 2 pairs of teeth | 1 pair semilunar cutting plates |
| Copulatory bursa | Large tripartite | Small, tripartite |
| Copulatory spicules | 2 hair-like spicules | Spicules fuse at tip into a barb |
| Vulva | Posterior half of the body | Anterior half of the body |
| Cervical Curvature | C-shaped | S-shaped |
| Remarks | “Old world Hookworm” Percutaneous & fecal oral route with transmammary transmission | “New World Hookworm” Purely percutaneous Predominant in Philippines |
Animal Hookworms
- A. braziliense & A. caninum – causes “creeping eruption” or cutaneous larva migrans (CLM)
- A. ceylanicum – first case was recorded in Ilocus Norte in 1968
Diagnosis
- Harada-Mori culture method
- PCR based
- ELISA
TREATMENT
- Albendazole
- Iron supplement & adequate diet
Strongyloides stercoralis
- Threadworm
- Free-living
- Capable of parthenogenesis
- INFECTIVE STAGE – FILARIFORM LARVAE
- MODE OF TRANSMISSION – SKIN / MUCOSAL PENETRATION
PATHOLOGY & CLINICAL MANIFESTATION
- Cochin-china diarrhea / Vietnamese diarrhea
- Autoinfection
- hyperinfection
DIAGNOSIS
- Baermann funnel gauze method
- Harada-Mori Culture
- Beale’s String test
- Duodenal aspiration
TREATMENT
- Ivermectin
Enterobius vermicularis
- Pinworm; seatworm; society/social worm
- Adult worm: anterior end with lateral wings or cephalic alae
- Egg: flattened on one side: D-shaped; Italian bread egg; embryonated after 6 hrs.
- INFECTIVE STAGE – EMBRYONATED EGG
- MODE OF TRANSMISSION – INGESTION/INHALATION
PATHOLOGY & CLINICAL MANIFESTATION
- Pruritus ani
- Oxyuriasis
- Insomnia
- Extraintestinal enterobiasis
- External autoinfection
DIAGNOSIS
- Graham’s scotch adhesive tape swab (perianal cellulose tape swab)
TREATMENT
- Mebendazole
- Albendazole
- Pyrantel Pamoate
Capillaria philippinensis
- Pudoc worm
- Mystery worm
- Capable of hyperinfection & autoinfection
CHARACTERISTICS
- NATURAL HOST – FISH-EATING BIRDS
- PEANUT – SHAPED w/ striated shells and flattened bipolar plugs
- INFECTIVE STAGE – INFECTIVE LARVAE
- MODE OF TRANSMISSION – INGESTION OF INFECTED FISH WITH LARVAE
- INTERMEDIATE HOST – FRESHWATER FISH / BRACKISH WATER FISH: BAGSIT
PATHOLOGY & CLINICAL MANIFESTATION
- Malabsorption syndrome
- Borborygmus and abdominal pain
DIAGNOSIS
- Direct smear/ wet mount / stool concentration technique
- ELISA (coproantigens)
- Duodenal Aspiration
