LECTURE 8.2 - TISSUE NEMATODES

TRICHINELLA SPIRALIS

First described by Tiedemann in 1822

TRICHINELLA SPIRALIS

Demonstrated in human cadavers in London by James Paget and Richard Owen in 1835

TRICHINELLA SPIRALIS

German investigators proved that raw or insufficiently cooked meat like pork causes human trichinellosis

TRICHINELLA SPIRALIS

Causes the greatest increase in eosinophils

TRICHINELLA SPIRALIS

All stages of development, including the larval and adult stages occur within a single host

• Trichinella spiralis

• Trichinella britovi

• Trichinella nativa

• Other species affecting humans

8 RECOGNIZABLE SPECIES OF TRICHINELLA

TRICHINELLA SPIRALIS

• Most important cause of trichinellosis in human

• Most adapted to pigs

TRICHINELLA BRITOVI

2nd most common species affecting humans

TRICHINELLA BRITOVI

Most widely distributed species among wild animals, can also infect pigs

TRICHINELLA NATIVA

Infects primarily wild carnivores in the frigid zones

Muscle worm, Trichina Worm/Garbage Worm

TRICHINELLA SPIRALIS

Common name:

Small Intestine

TRICHINELLA SPIRALIS

Habitat Adult:

Encysted in striated muscle

TRICHINELLA SPIRALIS

Habitat Larva:

Pigs and other mammals that are omnivores/carnivores

TRICHINELLA SPIRALIS

Final host:

Man

TRICHINELLA SPIRALIS

Accidental/ host:

Encysted larva

TRICHINELLA SPIRALIS

Diagnostic stage:

Encysted larva

TRICHINELLA SPIRALIS

Infective stage:

Ingestion of undercooked or raw meat with encysted larva

TRICHINELLA SPIRALIS

Mode of transmission:

With conical papillae

TRICHINELLA SPIRALIS

Male:

With club-shaped uterus; viviparous/larviparous

TRICHINELLA SPIRALIS

Female:

5-10 years

TRICHINELLA SPIRALIS

Average lifespan of encysted larva is _____ and can reach up to 40 years in humans

• Trichinosis

• Trichiniasis

• Trichinellosis

TRICHINELLA SPIRALIS

Disease/Condition:

diarrhea, nausea, abdominal cramps and general malaise

TRICHINELLA SPIRALIS

Symptoms that may develop within the first 24 hours include ________, all of which may suggest food poisoning

fever, facial (periorbital) edema, muscle pain, swelling and weakness

TRICHINELLA SPIRALIS

Muscle invasion:

Myocardia (develops after the 3rd week)

TRICHINELLA SPIRALIS

Most severe symptom:

• Enteric Phase

• Invasion Phase

• Convalescent Phase

PHASES OF INFECTION

Enteric Phase

Corresponds to stage of incubation and intestinal invasion

Invasion Phase

Corresponds to stage of larval migration and muscle invasion

Convalescent Phase

Corresponds to stage of encystment and encapsulation

• Muscle biopsy

• Immunotests

TRICHINELLA SPIRALIS

LABORATORY DIGANOSIS:

• Enzyme Immunoassays (EIA)

• Bentonite Flocculation Tests

• Bachman Intradermal Test

• Beck’s Xenodiagnosis

TRICHINELLA SPIRALIS

Immunotests:

Enzyme Immunoassays (EIA)

used for screening

Bentonite Flocculation Tests

used for confirmation

• Removal of muscle with encysted larvae

• Mebendazole, Albendazole

TRICHINELLA SPIRALIS

TREATMENT:

Freezing

destroys Trichinella spiralis larvae

77 degree Celsius (170 degrees Fahrenheit)

Recommended that meat should be cooked at a minimum of

GROUP A

SYMPTOMS:

Fever, eyelid facial edema, myalgia

GROUP B

SYMPTOMS:

Diarrhea, neurological signs, cardiac signs, conjunctivitis, sublingual hemorrhages, cutaneous rash

GROUP C

SYMPTOMS:

Eosinophilia (>1000 eosinophils/mL) high total IgE, high muscular enzymes

GROUP D

SYMPTOMS:

Positive serology, seroconversion, positive muscular biopsy

Cerebral Angiostrongyliasis

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Disease/Condition:

Rat lungworm

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Common name:

Rats

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Natural/Definitive host:

• Molluscs, slugs, and snails

• Pila luzonica (Kuhol);

• Brotia asperata (Suso)

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Intermediate hosts:

Filariform larva

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Infective stage:

Encysted larva

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Diagnostic stage:

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Modes of Transmission:

• Ingestion of intermediate host by man containing infective larva

• Ingestion of infected raw paratenic hosts, including fish, amphibians, reptiles, crustaceans, and vegetables contaminated with larvae

• Drinking contaminated water

Very thin and delicate

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

ADULTS:

Barber’s pole appearance

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Female worm:

Barber’s pole appearance

looping of whitish uterus to the red digestive tract

Elongated, ovoidal with delicate hyaline shells; unembryonated when oviposited

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

EGGS:

Eosinophilic Meningoencephalitis

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

SYMPTOMS AND PATHOLOGY:

Severe headache

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

Main symptom in all reported cases:

• Peripheral eosinophilia and increased eosinophils in CSF

• Lesions in brain (CT scan)

• ELISA

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

LABORATORY DIAGNOSIS:

Mebendazole

ANGIOSTRONGYLUS (PARASTRONGYLUS) CANTONENSIS

TREATMENT:

Abdominal Angiostrongyliasis

ANGIOSTRONGYLUS COSTARICENSIS

Disease/Condition:

ANGIOSTRONGYLUS COSTARICENSIS

Found primarily in the cotton rat and the black rat

ANGIOSTRONGYLUS COSTARICENSIS

Human infection is typically ingestion of salad contaminated with slugs or snails

ANGIOSTRONGYLUS COSTARICENSIS

Patient may experience lower right quadrant pain, abdominal pain similar to that manifested in appendicitis

DRACUNCULUS MEDINENSIS

Longest nematode of man (up to 1 meter)

Thick cuticle and a large uterus that fills the body cavity and contains rhabditoid larvae

DRACUNCULUS MEDINENSIS

Characteristic:

• Guinea Worm

• Fiery Serpent of the Israelites

• Medina Worm

• Dragon Worm

• Serpent Worm

DRACUNCULUS MEDINENSIS

Common names:

Subcutaneous tissue

DRACUNCULUS MEDINENSIS

Habitat:

Filariform larva

DRACUNCULUS MEDINENSIS

Infective stage:

Ingestion of infected copepods

DRACUNCULUS MEDINENSIS

Mode of Transmission:

Dracunculiasis

DRACUNCULUS MEDINENSIS

Subcutaneous infection:

Aquatic crustacean

DRACUNCULUS MEDINENSIS

Intermediate host:

• Metronidazole

• Thiabendazole

DRACUNCULUS MEDINENSIS

TREATMENT:

Toxocara canis

Dog Ascarid/Dog Roundworm

Toxocara cati

Cat Ascarid/Cat Roundworm

Man

TOXOCARA SPP.

Accidental host:

Embryonated eggs

TOXOCARA SPP.

Infective stage:

• Accidental ingestion of infective ova

• Ingestion of undercooked/viscera of infected paratenic hosts (beef, lamb, chicken, duck meat especially liver)

TOXOCARA SPP.

Mode of transmission:

• Visceral Larva Migrans (VLM)

• Ocular Larva Migrans (OLM)

TOXOCARA SPP.

SYMPTOMS AND PATHOLOGY:

Visceral Larva Migrans (VLM)

A result of migration and subsequent death of the larvae in the different tissues and organs

Visceral Larva Migrans (VLM)

Wheezing is a common sign

Visceral Larva Migrans (VLM)

Liver enlargement and necrosis may occur; heart may be affected (less common)

Ocular Larva Migrans (OLM)

Signs and symptoms manifested in the eye; occurs in children 5-10 years old

Invasion of retina

Ocular Larva Migrans (OLM)

Most serious consequence:

Covert toxocariasis (CoTOX)

Less specific syndrome: patients are asymptomatic and eosinophilia is less frequent

Detection of larvae from biopsy specimens

TOXOCARA SPP.

Definitive Diagnosis:

Serological tests

TOXOCARA SPP.

Recommended Laboratory Diagnosis:

1:32

Diagnostic for Visceral Larva Migrans (VLM)

1:8

Diagnostic for Ocular Larva Migrans (OLM)

• Albendazole

• Photocoagulation

TOXOCARA SPP.

TREATMENT:

ANISAKIS SIMPLEX

causes Herring Disease

ANISAKIS SIMPLEX

common in Japan

ANISAKIS SIMPLEX

Fish and Farine Mammals Roundworm

• Herring Worm

• Codworm

• Sealworm

ANISAKIS SIMPLEX

Common name:

Whales/Dolphins

ANISAKIS SIMPLEX

Definitive hosts:

Copepods

ANISAKIS SIMPLEX

1st Intermediate host:

Smaller fishes

ANISAKIS SIMPLEX

2nd Intermediate host:

Larger fishes

ANISAKIS SIMPLEX

3rd Intermediate host:

Filariform larva

ANISAKIS SIMPLEX

Infective stage:

Ingestion of raw, pickled, salted, smoked freshwater fish infected with larva or squid

ANISAKIS SIMPLEX

Mode of Transmission:

• Acute gastric presentation

• Intestinal anisakiasis

• Tingling-throat syndrome

ANISAKIS SIMPLEX

SYMPTOMS AND PATHOLOGY:

Acute gastric presentation

ANISAKIS SIMPLEX

Most commonly recognized clinical syndrome:

Tingling-throat syndrome

ANISAKIS SIMPLEX

caused by Pseudoterranova decipiens larvae

Patient’s food history

ANISAKIS SIMPLEX

Presumptive diagnosis:

Racoon Roundworm

BAYLISASCARIS PROCYONIS

Common name: