Goku Notes - Phasmids 2

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Hookworms Necator americanus

T h r ea ea d w o r m Strongyloides stercoralis

Ancylostoma duodenale

HOOKWORMS (N . am am e r i c a n u s a n d A . d u o d e n a l e   ) Hookworms have different stages.  Adult female female is longes longes than adult male. Can cause microcytic hypochromic anemia or Iron deficiency anemia Hookworms are bent on anterior end or mouth part. Hookworms causes infection in 576-740 individuals. 80 million are severely infected. Hookworms are blood feeding f eeding nematodes Different from bacterial infections Necator americanus and Ancylostoma duodenale are the most important hookworms infecting humans. Morphology

Rhabditiform larva Rhabditiform larva is the larva that hatches from the egg. Larger More attenuated posteriorly Indistinguishable Indistinguishable from each other Long buccal cavity Small genital primordium Filariform larva Infective stage Short esophagus Pointed tail Filariform larva Second stage larva Non feeding stage Infective stage Closed mouth Longer and more slender than rhabditiform larva

Rhabditiform larva First stage larva Feeding stage Non-infective stage Open mouth Short and more robust than filariform larva

(N. american us and A. duo denale)

Eggs Eggs are almost indistinguishable 60-75um long egg for N. americanus 35-40um wide egg for N. americanus 55-60um long egg for A. for  A. duodenale duodenale 35-40um wide egg for A. for  A. duodenale duodenale bluntly rounded end single thin transparent hyaline shell unsegmented at oviposition undergoes 2-8 cell stage of division when passed out in feces Goku Notes feat. NMC

Necator americanus

Conspicuous buccal spears which are also parallel throughout their length

Ancylostoma duodenale

Inconspicuous buccal spear Transverse striation on the sheath and tail region

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Goku Notes feat. NMC Adult worms Genital primordium is smaller in hookworms compared to S.stercoralis  A. duodenale is slightly larger than N. americanus Have single pair of male and female reproductive organs Male worm is 5-9mm by 0.30mm Male worm’s posterior end has a broad, membranous caudal bursa with rib like rays(for copulation) Female worms measure 9-11mm by 0.35mm

Teeth Head

Copulatory bursa Copulatory spicule Dorsal rays

A. duodenale

N. americanus

1% TWO

97% SEMILUNAR CUTTING PLATES

head is continuous in the same direction as the curvature of the body BROAD THAN LONG

head is curved opposite to the curvature of the body which like a hook at the anterior end LONGER THAN BROAD

SEPARATED;

FUSED

TRIPARTATE

BIPARTATE

Necator americanus

Kingdom: A n i m a l i a Phylum: N e m a t o d a   Class: Secernentea  Order: S t r o n g y l i d a   Family: A n c y l o s t o m a t i d a e Genus: Necator  Species: N e c at o r a m e r i c a n u s  

Cylindrical Fusiform Grayish white in color Has a buccal capsule head is curved opposite to the curvature of the body , making it look like a hook at the anterior end Has double curves and looks like an S Has 1 pair of ventral cutting plates Common in Philippines

A n c y l o s t o m a d u o d e n al e  

Kingdom: A n i m a l i a Phylum: N e m a t o d a   Class: Secernentea  Order: S t r o n g y l i d a   Family: A n c y l o s t o m a t i d a e Genus: A n c y l o s t o m a   Species: A n c y l o s t o m a duodenale 

Old world hookworms Sucks 0.2ml of blood per day per worm 2 pairs of teeth in adult work Larger than N. americanus Head is continuous in the same direction as the curvature of its body Has single curve and looks like C 2 pairs of ventral teeth

New world hookworms Semilunar cutting plates in adult worm Small Goku Notes feat. NMC

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Goku Notes feat. NMC E p i d e m i o l o gy o f H o o k w o r m s P r e s c h o o l a n d s c h o o l c h i l d r e n - 1 .1 -   1.9% prevalence Pregnan t wom en - 5.5% Ad olesc ent female - 2.8% Military and paramilitary personnel 46.9% I n d i g e n o u s p e o p l e o f D a v ao d e l N o r t e 13.6% Food h andlers in M etro Manila - 22.7% Food h andlers in Cebu- 14.88% WHO recommends mass drug a d m i n i s t r at i o n a m o n g s c h o o l a g e children atleast once a year for prevalence of 20% N.AME RICANUS -97% DUODENALE 1% MIXED INFECTION 2% I n f e c t i o n i s g r e at e r i n a g r i c u l t u r a l areas (farmers) Hookworms I n f e c t iv e s t a g e : f i l a r i f o r m o r L 3 l a r v a   D i a g n o s t i c s t a g e : u n e m b r y o n a t ed eggs 

Mode of Transmission Skin penetration of filariform or L3 larva

It will migrate into the alveoli then to the bronchus before ascending to the trachea and will be coughed out in the pharynx. Larva will be once again swallowed and will go to the small intestines where they will mature into adult worms and multiply.  Adult worms will copulate in the mucosa of the small intestines. Female lays 10-20,000 eggs per day. Eggs will be passed out in the environment. Eggs embryonate in warm soil with decaying vegetation. Rhabditiform larva will emerge from the egg in 24-48 hrs where it will start to feed and molt to its next stage, the filariform larva.  After 7-10 days, the larva undergoes 2 stage of molting and will become the filariform or L3 larva. Cats and dogs can also have hookworms (caninum in dogs and braziliense in dogs and cats) Eggs of these animal hookworms will be passed out in the soil where they will embryonate and become rhabditiform larva and later on filariform larva. In humans the filariform larva enters through penetration but they encyst in the skin and not migrate in the intestines or circulation. They infect subcutaneous of skeletal tissues and cause cutaneous larva migrans.

Life cycle Humans contract parasite through skin penetration of filariform larva.  After penetration, it will go to the venules. It will now migrate to circulation and goes to the heart and lungs where it enters the lung capillaries. Goku Notes feat. NMC

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Goku Notes feat. NMC Cat and dog hookworms Ancylostoma braziliense C at h o o k w o r m Has a pair of ventral teeth and a pair of small a c c e s s o r y t e et h

Ancylostoma caninum Dog hookworm Infects humans and causes creeping eruptions (cutaneous larva migrans) Has 3 pairs of teeth

Greater blood loss in A.duodenale than in N. americanus infections due to the presence of teeth in adult  A. duodenale Progressive anemia Microcytic anemia Hypochromic anemia Secondary anemia Iron deficiency anemia Hypoalbuminemia due to blood loss  Abdominal pain Stearorrhea Diarrhea Edema Weakness Dizziness No symptoms if the infestation is mild

P a th o g e n es i s o f h o o k w o r m s Extensive humo ral responses are SKIN is the site of entry .

produ ced in larva and adult

LUNGS as the site of larval migration

h o o k w o r m i n f ec t i o n s .

SMAL L INTESTINE as the habit at of

Celle immu ne response is prim arily

adult worms.

mediated by eosinop hils, mast cells and T helper 2 cells. U n l i k e i n a s c ar i a s i s , h o o k w o r m

Clinical manifestations

infections are often quite milder and remedial m easures are applied.

Maculopapular lesions and localized erythema at the site of skin penetration Severe itching known as ground itch or dew itch during dew mornings Itcina, edema and erythema at the penetration site Papulovesicular lesions lasting for 2 weeks Creeping eruptions due to dog hookworm infections (cutaneous larva migrans) Bronchitis and pneumonia/pneumonitis due to larval migration in the lungs Minute hemorrhage with eosinophilic and leukocytic infiltration during the migration stage

Diagnosis F i n a l d i ag n o s i s d e p e n d s o n t h e identification of th e ova or parasite egg in feces.

Direct fecal smear in heavy infections though it may not be useful for light infections (not too detectable if the infection is light) E g g c o u n t f o r d i r e c t f e c a l s m e a r i s < 4 00 eggs p er gram feces.

Kato thick or Katokatz technique which is a quantitative diagnosis and has Goku Notes feat. NMC

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Goku Notes feat. NMC increased detection rates since more stools are examined Disadvantage of Katokatz:

Regular mass administration Good sanitation Promotion of good hygiene S t r o n g y l o i d e s s t er c o r a l i s  

r a p i d c l e a r an c e o f h o o k w o r m f t e r 3 0 -   6 0 m i n . w i t h t h e u s e o f g l y c e r i n e as clearing agent

ELISA Zinc sulfate centrifugal flotation and Formalin ether concentration methods Concentration techniq ues use greater quantity of sto ol that may increase the sensitivity.

FLOTAC - centrifugal flotation have higher sensitivity for diagnosis Harada mori cultures - egg hatching test H a r a da m o r i c u l t u r e s a l l o w h a t c h i n g o f l a r v a f r o m e g g o n s t r i p o f f i l te r p a p er with o ne end immersed in water(for

Kingdom: A n i m a l i a Phylum: N e m a t o d a   Class: Secernentea  Order: R h a b d i t i d a   Family: S t r o n g y l o i d i d a e Genus: S t r o n g y l o i d e s   Species: S t r o n g y l o i d e s stercoralis 

Known as threadworm or strongy Smallest pathogenic nematode Opportunistic pathogen in immunocompromised host 2.4-4.7 mm long Common in tropical, subtropical and temperate climates Has free living and parasitic life cycle

specie id entification)

Morphology Treatment  Albendazole (ovicidal and larvicidal) 400mg Mebendazole 500mg

Egg 50-58um by 30-34um clear thin shell and similar to hookworm Rhabditiform larva

Mode of action of Mebendazole and Albendazole: blocks the glucose uptake b y m o s t i n t e s t i n a l an d t i s s u e nematodes.

Iron supplements for anemia and hypoalbuminemia Prevention  Access to clean water Goku Notes feat. NMC

Rhabditiform larva has shorter buccal canal. Genital primordium is easily seen in Strongyloides. 25 um by 16 um in measurement elongated esophagus with pyriform posterior bulb slightly smaller and less attenuated posteriorly shorter buccal cavity Page 5

Goku Notes feat. NMC large genital primordium Filariform larva

Not been reliably identified

Long esophagus 550um usually smaller with distinct cleft at the tip of the tail Filariform larva Second stage larva Non feeding stage Infective stage Closed mouth Longer and more slender than rhabditiform larva

Male worms

Rhabditiform larva First stage larva Feeding stage Non-infective stage Open mouth Short and more robust than filariform larva

Adult Worms Can be free living or parasitic

Female worms 2.2mm by 0.04mm Colorless, semi-transparent with finely striated cuticle Slender tapering anterior end and has short conical pointed tail Short buccal cavity has 4 indistinct lips Longer esophagus extend to the anterior fourth of the body Intestine is continuous to the subterminal anus Vulva is located one-third the length of the body from posterior end Uteri contain a single file of 8-12 thin shell, transparent, segmented ova (5058um by 30-34um) E p i d em i o l o g y o f T h r e ad w o r m s S o i l t r an s m i t t e d h e l m i n t h More frequent in male children 7- 

FREE LIVING ADULT W ORMS

1 4y r s o l d t h a n a m o n g f e m a l e s a n d adult

Male worms

Auto infection may remain for more than 30yrs even after leavin g the

0.7mm by 0.04mm Smaller than female Has ventrally curved tail Has two copulatory spicules, a gubernaculum but no caudal alae Female worms 1mm by 0.06 mm Smaller than parasitic female Muscular double-bulled esophagus Intestine is straight cylindrical tube

e n d e m i c a r e as

Threadworm I n f e c t i v e s t a g e: f i l a r i f o r m o r L 3 l a r v a   Diagnostic stage: rhabditiform larva 

Mode of Transmission Skin penetration by filariform larva

PARA SITIC LIVING ADUL T WORMS

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Goku Notes feat. NMC Life cycle P a t h o g e n e s i s o f th r e a d w o r m s

Humans contract the parasite through skin penetration. It will go to the circulation and to the alveoli and bronchus then go to the larynx. It will be coughed out and swallowed and now go to the small intestines particularly in the duodenum where it will develop for about a month and mature into an adult worm and cause autoinfection. Copulation or parthenogenesis occurs, and eggs are deposited in the intestinal mucosa to hatch as rhabditiform larva. Females have the capacity to reproduce through parthenogenesis. Rhabditiform larva migrate to the large intestine and develop into filariform larva and invade the intestinal mucosa and reenter to the circulation (AUTOINFECTION). Rhabditiform larva are the ones passed out in feces and develops into free living parasite on the soil. In the free living life cycle of the parasite, the filariform larva does not need to penetrate the skin to mature, although it is really capable of skin penetration. Copulation of free living male and free living female adult worms produces egg which develops into rhabditiform larva. Rhabditiform larva start to feed, molt and transform to filariform larva which penetrates the skin and reenter to the circulation

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SKIN is the site of entry . Larval migration throug hout the BODY SMAL L INTESTINE as the habit at of adult worms  I n t e s ti n a l m u c o s a p e n e t r at i o n b y t h e female worm .

Clinical manifestations First phase larval invasion of the skin prod uce erythema and pruritic elevated h e m o r r h a g i c p a p u l es S e c o n d p h a s e (l a r v a l m i g r a t i o n p h a s e ) the lungs are destroy causing lo bar pneumo nia with hemorrhage c o u g h a n d t r a c h e a l i r r i t at i o n (mimicking bronchitis) Third ph ase adult female wor ms are found in intestinal mucosa from the pylorus t o t h e r e c t u m . g r e a te s t n u m b e r i n d u o d e n a l a n d u p p e r j e j u n a l r eg i o n s .

Skin erythema Pruritic elevated hemorrhagic papules Lobar pneumonia Cough Tracheal irritation Diarrhea with alternating constipation Bloody and watery diarrhea Loss of appetite Emaciation  Anemia Page 7

Goku Notes feat. NMC Hyperinfection - the migration of larva through the body and penetration of intestinal mucosa by adult female may occur simultaneously Light infection

Hyperinfection - is a syndr ome of a c c e l er a t e d a u t o i n f e c t i o n w / c u s u a l l y , b u t n o t i n v a r i a bl y o c c u r s i n t h e immunocompromised. manifest exacerbation of

do not cause intestinal symp toms prognosis is good Moderate infection c a u s e d i a r r h e a a l te r n a t i n g w i t h constipation high m ortality rates due to massive invasion H e av y i n f e c t i o n

g a s t r o i n t e s t i n a l an d p u l m o n a r y symp toms and in c. # of larva in stool and sputum c h r o n i c s t r o n g y l o i d i as i s i s asymptomatic i n t e r m i t t e n t v o m i t i n g , d i a r r h e a, constip ation, borb orygm ianal pruritis,uticaria and larva currens rashes recurrent asthma and nephritic syndrome

p r o d u c e i n t r a c t a b l e, p a i n l e s s , i n t e r m i t t e n t d i a r r h e a (c o c h i n c h i n a diarrhea)  –characterized by num erous episodes of watery and bloody stools high m ortality rates due to massive invasion

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Diagnosis Unexplained eosinophilia-clue pointing to strongyloidiasis Concentration technique like BAERMANN FUNNEL GAUZE METHOD HARADA-MORI CULTURE – one of the most successful methods in parasite identification Beale’s string test,duodenal aspiration, and small bowel biopsy larvae may found in sputum and urine modified harada-mori make use of polethylene plastic bag or tube instead of glass tube culture technique. is practical ,low cost, suited for mass screening as well as individual diagnosis

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Goku Notes feat. NMC Treatment  Albendazole Thiabendazole Alb endazole and Thiabendazole are c o n t r a i n d i c a t ed i n p r eg n a n t a n d i n hyp ersensitivity to drugs

Ivermectin - provides the best result in chronic uncomplicated strongyloidiasis with regard to efficacy and tolerability S .stercoralis is quite sensitive to ovicidal and larvicidal action Alb endazole, Thiabend azole and I v e r m e c t i n - t r e at h y p e r i n f e c t i o n o r disseminated disease singly or in combination.

Side effects of the medications Albendzole

thiabendazole

Transient gastrointestinal discomfort and headache

Dizziness gastrointestinal irritation drowsiness pruritus headache lasting for several hours

Add itional content from: NMC Sources: lectures, Belizario

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