Nematodes Flashcards
Nematodes Classification as per habitat
Intestinal - Small and Large intestine
Somatic (different organs)
Nematodes affecting Small intestine
Round worn
Hookworm
Strongyloides
Nematodes affecting large intestine
LET
Trichuris
Enterobius
Example of Somatic Nematodes
La,la,lu
Filaria
Trichinella
Dracunculus
Classification of nematodes on basis of Eggs/Larvae
Viviparous
Oviparous
Ovoviviparous
Viviparous Nematodes
Directly lays down larvae
Ex - La La Lu
Filaria, Trichinella, Dracunculus
Oviparous Nematodes and Examples
Lays egg - later turns into larvae
Ex - laTER
Roundworm, Hookworm, Trichuris, Enterobius
Ovoviviparous Nematodes and Examples
Lay egg and it immediately hatch out into larvae
Example - Strongyloides
Most common helminthic infection in the world
Ascaris lumbricoides/Roundworm
Male and females shape in Ascaris lumbricoides
Females - longer
Males - curved post. End, Shorter
Infective form in case of Ascaris lumbricoides
Egg/Embryonated egg
Route of transmission and location affected by Ascaris lumbricoides
Route - Oral
Location - Small intestine , Also lung stage +
IP in case of Ascaris lumbricoides infection
60-75 days
Clinical features in case of Ascaris lumbricoides
Malabsorption
Loeffler’s syndrome/Eosinophilic Pneumonitis
Difference between fertilized and unfertilized eggs in Ascaris lumbricoides sample
Fertilized egg - Thick albumin coat, Crescentric space +, Float in saturated salt solution
These things doesn’t seen in Unfertilized egg
Treatment of Ascaris lumbricoides
Albendazole
Visceral larva migrans/Ocular larva migrans means
infection caused by parasitic roundworms passed from animals to humans
Visceral larva migrans life cycle
Ingestion of Non human roundworms - Rhabditiform larva - Filariform larva - Pass through LN and blood and reaches right side of heart but unable to pass through Pulmonary circulation - invades visceral organs
Trichuris Trichura AKA
Whipworm
Infective form in case of Trichuris Trichura
Embryonated egg
Route of transmission and location affected in case of Trichuris Trichura/Whipworm
Route - Ingestion
Location - Large intestine
No lung stage
IP in case of Trichuris Trichura
70-90 days
Clinical features seen in case of Trichuris Trichura
Dysentery - blood in stools - IDA
Recurrent Rectal prolapse
Endoscopy finding in case of Trichuris Trichura
Often shows Adult worms attached to Bowel mucosa (Coconut cake reaction)
Treatment of Trichuris Trichura
Albendazole
Enterobius vermicularis AKA
Pinworm or Threadworm
Location of Enterobius vermicularis
Vermiform appendix (extreme tip)
Male and female shape in case of Enterobius vermicularis
Fusiform shape
Female - longer
Male - Shorter, curved/coiled post end
On Ant end - Presence of cervical alae
Infective stage in case of Enterobius vermicularis
Embryonated egg
Route and location affected in case of Enterobius vermicularis
Route - Oral
Location - Large intestine, No lung stage
Autoinfection in case of Enterobius vermicularis
Perianal pruritis - scratch - deposit egg in Nails - leads to autoinfection (ingested again)
Retroinfection in case or Enterobius vermicularis
Larvae go back into intestine
IP and treatment of Enterobius vermicularis
IP - 35-45 days
Treatment - Albendazole
Enterobius vermicularis lays egg where and at what time, C/F
At night, lays egg at perianal region - causes Perianal pruritus (Can spread to genital areas)
Sample collecting methods in case of Enterobius vermicularis
Collect eggs with help of NIH Swab
Scotch tape method (Infants)
Shape of egg of Enterobius vermicularis
D shape - Planoconcave egg with tadpole larva
Finding on appendix biopsy in case of Enterobius vermicularis
Cervical alae seen
Ancylostoma AKA
Hookworm
Ancylostoma AKA
Hookworm
Ancylostoma Species seen in new world
Necator americanus
Ancylostoma species seen in Old world
Ancylostoma duodenale
Infective form in case of Ancylostoma
Filariform larvae
Route of transmission and location of Ancylostoma/Hookworm
Route - Penetration of skin
Location - Small intestine
Lung stage +
Route of transmission and location of Ancylostoma/Hookworm
Route - Penetration of skin
Location - Small intestine
Lung stage +
IP and treatment of Ancylostoma
IP - 40 to 100 days
Treatment - Albendazole
IP and treatment of Ancylostoma
IP - 40 to 100 days
Treatment - Albendazole
Clinical features in case of Ancylostoma
Ground itch
Creeping eruption
IDA (SI)
Pulmonary symptoms
Clinical features in case of Ancylostoma
Ground itch
Creeping eruption
IDA (SI)
Pulmonary symptoms
Diagnosis of Ancylostoma
Egg with blastomeres
Unembryonated egg - Fresh stool
Chandeler index
Average no. Of hookworm eggs per gram of feces for the entire community
How much Chandler index is a public health problem
Above 300
Female and male shape in case of Ancylostoma
Female - Longer
Male - Shorter, Capsulatory bursa + , Post end have umbrella like expansion
Eggs and Rhabditiform larva in case of Ancylostoma duodenale and Necator americanus
Both have same
Adult worm is larger in Ancylostoma duodenale or Necator americanus
Ancylostoma duodenale - larger
Necator americanus - shorter
Which is more pathogenic - Ancylostoma duodenale and Necator americanus
Ancylostoma duodenale - more pathogenic
Necator americanus - less pathogenic (ground itch more severe)
Which is more pathogenic - Ancylostoma duodenale and Necator americanus
Ancylostoma duodenale - more pathogenic
Necator americanus - less pathogenic (ground itch more severe)
Head end in case of Ancylostoma duodenale and Necator americanus
Ancylostoma duodenale - 4 ventral teeth, 2 dorsal teeth (total 6)
Necator americanus - 4 chitinous plates
Head end in case of Ancylostoma duodenale and Necator americanus
Ancylostoma duodenale - 4 ventral teeth, 2 dorsal teeth (total 6)
Necator americanus - 4 chitinous plates
Tail end in case of Ancylostoma duodenale and Necator americanus
Ancylostoma duodenale - Spicules free
Necator americanus - two Spicules fused
Cutaneous Larva migrans caused by
Ancylostoma braziliense
Cause of visceral larva migrans and cutaneous Larva migrans
Visceral larva migrans - A/w roundworms
Cutaneous larva migrans - a/w Hookworm
Infective stage in case of Visceral larva migrans and cutaneous Larva migrans
Visceral larva migrans - Embryonated eggs
Cutaneous larva migrans - Filariform larva
Route of transmission of Visceral larva migrans and Cutaneous larva migrans
Visceral larva migrans - Ingestion
Cutaneous larva migrans - Skin penetration
Route of transmission of Visceral larva migrans and Cutaneous larva migrans
Visceral larva migrans - Ingestion
Cutaneous larva migrans - Skin penetration
Diagnosis in case of Visceral larva migrans
Toxocara specific antibody test
PCR (most specific)
Diagnosis in case of Visceral larva migrans
Toxocara specific antibody test
PCR (most specific)
Diagnosis in case of Cutaneous larva migrans
Physical exam of advancing serpingous track in skin
Treatment in case of Cutaneous larva migrans
Ivermectin
Treatment in case of Cutaneous larva migrans
Ivermectin
Smallest nematode known to cause human infection
Strongyloides stercoralis
Strongyloides Stercoralis Classified on basis of Eggs/larva
Ovoviviparous orgnaism - immediately releases larvae
Strongyloides Stercoralis Classified on basis of Eggs/larva
Ovoviviparous orgnaism - immediately releases larvae
Parthogenesis in Strongyloides Stercoralis
Single parent - female - eggs (by asexual)
Autoinfection In case of Strongyloides Stercoralis
Rhabditiform larva - penetrates Intestine - Autoinfection
Direct cycle in case of Strongyloides Stercoralis
After excreting in stool - immediately Rhabditiform larva turns into Filariform larva - enters back inside
Direct cycle in case of Strongyloides Stercoralis
After excreting in stool - immediately Rhabditiform larva turns into Filariform larva - enters back inside
Indirect cycle in case of Strongyloides Stercoralis
Excreted out - Rhabditiform larva - adultworms - gives Rhabditiform larva - Filariform larva
Indirect cycle in case of Strongyloides Stercoralis
Excreted out - Rhabditiform larva - adultworms - gives Rhabditiform larva - Filariform larva
Infective form in case or Strongyloides Stercoralis
Filariform larva
Infective form in case or Strongyloides Stercoralis
Filariform larva
Route of transmission in case of Strongyloides Stercoralis
Skin/autoinfection
Route of transmission in case of Strongyloides Stercoralis
Skin/autoinfection
Location affected in case of Strongyloides Stercoralis
Small intestine
Lung stage +
IP and Treatment in case of Strongyloides Stercoralis
IP - 17 to 28 days
Treatment - Ivermectin
IP and Treatment in case of Strongyloides Stercoralis
IP - 17 to 28 days
Treatment - Ivermectin
Diagnostic form in case of Strongyloides Stercoralis
Rhabditiform larva
Diagnostic form in case of Strongyloides Stercoralis
Rhabditiform larva
Identification of Rhabditiform larva
Double bulb esophagus
Tapering end
Identification of Filariform larva in case of Strongyloides Stercoralis
Notched end
Identification of Filariform larva in case of Strongyloides Stercoralis
Notched end
Rhabditiform larva seen in Strongyloides Stercoralis
Stool sample
Filariform seen in case of Strongyloides Stercoralis
Hyperinfection and disseminated infection may show in sputum, stool and body fluids
Filariform seen in case of Strongyloides Stercoralis
Hyperinfection and disseminated infection may show in sputum, stool and body fluids
Clinical features of Strongyloides Stercoralis
Cutaneous larva currens
Pulmonary
Intestinal
Can be associated with Hyperinfection syndrome (GIT, Lung - Severe)
Disseminated infection (all over the body)
Clinical features of Strongyloides Stercoralis
Cutaneous larva currens
Pulmonary
Intestinal
Can be associated with Hyperinfection syndrome (GIT, Lung - Severe)
Disseminated infection (all over the body)
Trichinella spiral features of male and females
Females 2 times longer
Claspers in male hold female during mating
Trichinella spiral features of male and females
Females 2 times longer
Claspers in male hold female during mating
Host in case of Trichinella Spiralis
Pig
Alternative/dead end host in Trichinella Spiralis
Human
Alternative/dead end host in Trichinella Spiralis
Human
Infective form in Trichinella Spiralis
Encysted larva (in striated larvae)
Infective form in Trichinella Spiralis
Encysted larva (in striated larvae)
Lab diagnosis in case of Trichinella Spiralis
Muscle biopsy - near tendon insertion of deltoid
Bachman intradermal test
Xenodiagnosis (animal studies)
Lab diagnosis in case of Trichinella Spiralis
Muscle biopsy - near tendon insertion of deltoid
Bachman intradermal test
Xenodiagnosis (animal studies)
Treatment in case of Trichinella Spiralis
Albendazole
Treatment in case of Trichinella Spiralis
Albendazole
Dracunculus medinesis AKA
Guinea worm
Dracunculus medinesis AKA
Guinea worm
Dracunculus medinesis eradicated under which programme
National guinea worm eradication progamme - clean drinking water, Abate (Larvicide)
Dracunculus medinesis/Guinea worm associated with which type of water
A/w drinking dirty water
Dracunculus medinesis/Guinea worm associated with which type of water
A/w drinking dirty water
Definitive and intermediate host in case of Dracunculus medinesis
Definitive - Human
Intermediate - Cyclops
Definitive host in case of Dracunculus medinesis
Human
Guinea adult worm resides in
Subcutaneous tissue - gravid female male s/c tunnel (Blisters) to discharge larvae on contact with water
Larvae coming out from blister
Guinea adult worm resides in
Subcutaneous tissue - gravid female male s/c tunnel (Blisters) to discharge larvae on contact with water
Larvae coming out from blister
Filarial Nematodes include which organisms
Wucheraria bancrofti
Brugia Malayi
Loa Loa
Mansonella prestans
Mansonella ozzardi
Onchocerca volvulus
Filarial Nematodes include which organisms
Wucheraria bancrofti
Brugia Malayi
Loa Loa
Mansonella prestans
Mansonella ozzardi
Onchocerca volvulus
Structure of Wucheraria bancrofti
Sheathed
Nuclei do not extent to tip of tail
Wucheraria bancrofti Vector
Nocturnal
Vector - Culex, anopheles, Aedes
Wucheraria bancrofti Vector
Nocturnal
Vector - Culex, anopheles, Aedes
Brugia Malayi Structure
Sheathed
2 nuclei at tip of tail
Brugia Malayi Structure
Sheathed
2 nuclei at tip of tail
Brugia Malayi Vector
Nocturnal
Vector - Mansonia
Brugia Malayi Vector
Nocturnal
Vector - Mansonia
Loa loa structure
Sheathed
Nuclei form Continous row in tip of tail
Loa loa structure
Sheathed
Nuclei form Continous row in tip of tail
Brugia Timori Vector
Nocturnal
Vector - Anopheles
Loa Loa vector
Diurnal
Vector - Deer flies (Chrysops)
Mansonella Prestans Structure
Unsheathed
Nuclei extend to tip of tail (persistent)
Mansonella Ozzardi Structure
Unsheathed
Nuclei do not Extend to tip
Mansonella Ozzardi Structure
Unsheathed
Nuclei do not Extend to tip
Mansonella vector
Non periodic
Vector - Midges
Mansonella vector
Non periodic
Vector - Midges
Onchocerca volvulus structure
Unsheathed
Nuclei do not extend to tip
Onchocerca volvulus vector
Non periodic
Vector - Blackflies
Onchocerca volvulus vector
Non periodic
Vector - Blackflies
Sheathed Filarial Nematodes
Wucheraria bancrofti
Brugia Malayi
Loa loa
Sheathed Filarial Nematodes
Wucheraria bancrofti
Brugia Malayi
Loa loa
Unsheathed Filarial Nematodes
Mansonella prestans
Mansonella ozzardi
Onchocerca volvulus
Unsheathed Filarial Nematodes
Mansonella prestans
Mansonella ozzardi
Onchocerca volvulus
Definitive host in case of Filarial Nematodes
Man
Definitive host in case of Filarial Nematodes
Man