nematodes hookworm
DESCRIPTION
August 25, 2010TRANSCRIPT
NEMATODES: HookwormsGeneral Info Hookworm (in General) Strongyloides stercoralis
CN ThreadwormFH Human/Nonhuman (Group) ManH Small intestine Small intestinesLife Span Max: 15 yearsMOT Ingestion (Human)
Skin penetration (Nonhuman)Skin penetration
DS Embryonated Ova (Stool) Rhabditiform larva (Stool)IS Filariform Larva (Soil) – L3 Filariform LarvaSrc. of Infection Soil-transmitted helminth (STH) STDMorphology Meromyarian (2-5 cells per dorsal/ventral half) Meromyarian
FACULATATIVELoves warm area = nonfeeding
Chemoreceptor Ampids ✔ ✔
Phasmids ✔ ✔
Attachment/Dental pattern Bite: intestinal mucosa Penetration in intestinal mucosa: Honeycomb intestinal mucosaParasitic Free living
Male SizeRefer to a specific parasite Not been reliably identified
0.7mmPosterior Ventrally curved tailSpicules Copulatory spiculesGubernaculum Layer Smaller: Microconspicous Conspicuous (w/o Cephalic alea)
Female Color
Refer to a specific parasite
Colorless, semi-transparent Colorless, semi-transparentCovering Fine striated cuticleSize 2.2 mm 1 mmType Parthogenetic OviviparusAnterior Slender taperingEsophagus Long slender, 3mm Double bulb esophagusBuccal Cavity Short, 4 indistinct LipsPosterior Short conical tailVulva 1/3 Length of the bodyIntestine Continuous to subterminal anus Straight cylindrical tubeUterus 1 Uteris, single file of 8-12segmented
ova [50-58 μm]2 Horn Uterus [Embryonated eggs]
Rhabditiform(Feeding stage)>Open buccal cavity>HK: more attenuated
Buccal Cavity
Long buccal cavity [Image from CDC/PHIL]
[Free-living]-225 μm-Elongated Esophagus -Pyriform posterior bulb-Short buccal cavity
Genital Primordium
Smaller LargerFilariform(Non-feeding stage)>(MOT) Closed buccal cavity
SheathedPointed posterior
550μmNonsheathed
Barbed posterior
Embroynated Ova> Single thin walled hyaline cell wall> Blastomere (6~8)
Image by Tai Soon Yong Thin shelled ova of Strongyloides stercoralis. Measuring 50µm by 30µm, they are smaller than Hookworm eggs. (SOURCE: CDC)
Pathology Pneumonitis/Wakana disease
Ground itch, Coolie itch, Mazza larva, Dev itch
HW anemiaHypoalbuminema
Microcytic Hyperchromic Anemia of IDA
Cochin China Diarrhea/Vietnam Diarrhea
Autoinfection
Hookwrom dermatitis
Pneumonitis/Wakana disease
Ground itch, Coolie itch, Mazza larva, Dew itch
Lung Heart Migration
3 Life Cycle of S. stercoralis1. Direct2. Indirect3. Autoinfection
Dx Harada Mori Culture Method
DFS
Kato technique
Kato-Katz
Conc. Tech=ZnSO4/Brine CT=Centrifugal floatation=FECT
Harada Mori Culture Method
Stoll/Beaver Technique
Baerman Culture Technique
Duodenal aspirate (Beale’s String Test/Entero String Test)
Tx AbendazoleMebendazole
AbendazoleThiabendazole
Prevention(HK & S. stercoralis)
1. Sanitary disposal of human feces2. Wearing of shoes, slippers and boots3. Health education on personal, family and community hygiene
4. Treatment of infected individuals5. Mass chemotheraphy when prevalence is greater than 50%6. Protection of susceptible individuals by improving household
income and diet to prevent malnutrition
>Human Ancylostoma duodenale Necator americanus
CN Old World Hookworm New World HookwormMOT Ingestion/Skin penetrationSrc. of Infection STH STHMorphology Color Grayish white Grayish white
Cylindrical, Fusiform Cylindrical, FusiformHead Not pointed, curved PointedMouth Thistle shape Funnel shapeEsophagus No gap between esophagus & intestines With gapBody Curvature C-shape S-shapedDental Pattern Adult Ancylostoma duodenale worm. Anterior end with mouth parts visible.
Courtesy of Patrick W Hickey, MD.
2 pair true ventral teeth, 1 pair median teethinconspicuous
Adult Necator americanus worm. Anterior end with mouth parts visible. Courtesy of Patrick W Hickey, MD.
Semi-lunar Cutting plates (Ventral & Dorsal)Conspicuous buccal spear
Posterior Not pointed tailInconspicuous transverse striation
Pointed tailConspicuous transverse striation
MaleSize 8-11mm 5-9mmBursa Bell shaped Fan shapedSpicule Straight, plain, bristle like BarbedDigits Tripartite Bipartite
Female Straight pointy 9-11mmEmbryonated Ova 25,000-30,000 eggs/day 9,000 eggs/day
>Nonhuman Ancylostoma caninum Ancylostoma braziliense
CN Dog hookworm Cat HookwormFH Dog Dogs/CatMorphology Smallest HWAttachment/Dental pattern
3 pair Ventral teeth 1 pair median teeth
Male
10mm
Bursa: Flare with long slender rays
5mm
Bursa: Round with short shubby rays
Female 40mm
9mm Pathology CLM: Cutaneous Larva Migrans/Creeping eruption in human
↑EosinophiliaPenetration of stratum granulosum