Tissue Nematodes

Question 1

Tissue Nematodes

Answer 1

Trichinella sprialis
Dracunculus medinensis
Filariasis
Loa loa
Onchocerciasis

Question 2

Common name: Trichina worm

Answer 2

Trichinella spiralis

Question 3

Found in undercooked pork (bear/horse) and game meats worldwide

Answer 3

Trichinella spiralis

Question 4

Pathogenesis
 Adults in the intestines: Mild to severe diarrhea
 Larval migration: High eosinophilia
 Allergic and toxic reactions
 May be fatal

Answer 4

Trichinella spiralis

Question 5

Larval encystment: Primarily in striated muscle
Rheumatoid pain
Toxic reaction
May be fatal: Five larvae per gram of body weight
Fatalities often within 4 to 8 weeks
Caused by: Toxemia, pneumonitis, myocardial failure, or trichinous encephalitis

Answer 5

Trichinella spiralis

Question 6

Infective third stage larvae encyst in striated muscle

Answer 6

Trichinella spiralis

Question 7

Non-striated muscle and other tissues do not support development to third stage larvae
Larvae cause local inflammation and tissue damage that have serious pathologic consequences (myocarditis, encephalitis, meningitis)

Answer 7

Trichinella spiralis

Question 8

Watery diarrhea, vomiting, abdominal discomfort, nausea during enteral phase.
Facial and periorbital edema, fever, weakness, malaise, myalgia, urticarial rash, conjunctivitis and conjunctival and subungual hemorrhages appear during systemic phase (larvae disseminate).
Pts with high infection burden may die of myocarditis, encephalitis, or pneumonia.
Muscle pain and weakness in chronic cases.

Answer 8

Trichinella spiralis

Question 9

Consider Trichinosis in patients presenting with myositis, eosinophilia 40-50% in a differential, fever, elevated creatine phosphokinase and lactate dehydrogenase

Answer 9

Trichinella spiralis

Question 10

Size
Male: About 1.5 mm
Female: 3 to 4 mm
Shape: Slender, tapers to larger posterior end
Color: Colorless
Male has two caudal appendages

Answer 10

Trichinella spiralis

Question 11

Adults in small intestine mating and depositing larvae (mild phase)

Larvae migrate to striated muscles (severe phase) edema, eosinophilia, myositis, death can occur

Answer 11

Trichinella spiralis

Question 12

Larvae survive in “nurse cells” for about 6 years.

Diagnosis: history, clinical signs, muscle biopsy

Answer 12

Trichinella spiralis

Question 13

Common name: Guinea worm

Answer 13

Dracunculus medinensis

Question 14

Female migration: Severe allergenic reactions

Toxemia: As the female reaches the surface of the body

Gastrointestinal upset

Blisters: Usually on lower extremities

• Severe burning and itching (pruritis)
• Symptoms are relieved when the blister ruptures

Answer 14

Dracunculus medinensis

Question 15

Surgical removal of the adult worm, “Twist-stick” method

Immersion of affected body part in cool water to coax worm from lesion

No antihelmintic drug is effective

Answer 15

Dracunculus medinensis

Question 16

Shape: Elongated, cylindrical, rope-like
Color: White
Buccal structures: Small triangular mouth surrounded by a quadrangular sclerotized plate

Answer 16

Dracunculus medinensis

Question 17

Acquired by ingesting an infected copepod, usually in water.

Larvae penetrate into humans deep connective tissue, mate, then migrate to subcutaneous tissues.

Answer 17

Dracunculus medinensis

Question 18

Maturity takes about a year.

Gravid female creates an ulcer in the lower limbs and releases larvae upon contact with water.

Diagnosis: clinical signs of muscle pain, ulcer

Answer 18

Dracunculus medinensis

Question 19

Lymphatic filariasis

Answer 19

Wucheria bancrofti

Burgia malayi

Question 20

Mainly blood/lymphatic organisms.

Generally transmitted via bites from flies/mosquitoes

Most are tropical diseases

Answer 20

Microfilariae

Question 21

Once in blood, go to target sites and mature at those locations, causing symptoms

Symptoms include inflammation and swelling due to edema or blockage of vessels

Answer 21

Microfilariae

Question 22

Habitat: Lymphatic system
Intermediate host (vector): Mosquitoes
Reservoir host: None
Infective form: Filariform larva
Mode of infection: Inoculation

Answer 22

Wuchereria bancrofti

Question 23

Common name: Elephantiasis worm

Pathogenesis: Elephantiasis, fibrosis, thrombi, lymphatic inflammation, granulomatous infiltration

Effective against microfilariae, poor impact on adults which live for 5-7 years.

Doxycycline kills Wolbachia symbionts* and may reduce fecundity and shorten reproductive life span of adults

Answer 23

Wuchereria bancrofti

Question 24

The most severe cases are referred to as elephantiasis

Answer 24

Wuchereria bancrofti

Question 25

History is important. Exposure to mosquitoes in endemic areas Microscopic examination of thick and thin blood smears. Best obtained at night. Nucleopore concentration and other methods (Knott’s Conc.) are helpful ELISA serology is reportedly available

Answer 25

Wuchereria bancrofti

Question 26

Common name: Elephantiasis worm

Answer 26

Brugia malayi

Question 27

``` Habitat: The lymphatic system Intermediate host (vector): Mosquitoes Reservoir host: None Infective form: Filariform larva Mode of infection: Inoculation ```

Answer 27

Brugia malayi

Question 28

Pathogenesis: Elephantiasis, fibrosis, thrombi, lymphatic inflammation, granulomatous infiltration

Answer 28

Brugia malayi

Question 29

Specimen processing: Giemsa or Hematoxylin/Eosin stains Specimen of choice: Blood Periodicity: Nocturnal with some subperiodic strains

Answer 29

Brugia malayi

Question 30

Adults in lymphatics, microfilariae in blood vessels around the lungs or peripheral areas. Symptoms: from adult worms, lymphangitis, lymphadenitis, can lead to elephantiasis Diagnosis: Blood test for microfilariae, sonography, may have serology or PCR

Answer 30

W. bancrofti B. malayi (lymphatic filariasis)

Question 31

Common name: Eyeworm

Answer 31

Loa loa

Question 32

Pathogenesis: Calabar swelling, urticaria, fever, neurologic symptoms, allergenic responses, irritation and destruction of ocular tissues

Answer 32

Loa loa

Question 33

Habitat: The subcutaneous and deep connective tissue Intermediate host (vector): Tabanid fly, Chrysops species Reservoir host: Monkeys Infective form: Filariform larva Mode of infection: Inoculation

Answer 33

Loa loa

Question 34

Most persons are asymptomatic. Transient Calabar swellings are noted in some Adult worms may migrate to the conjunctiva – eye worm Renal complications (hematuria, proteinuria) and encephalitis may be noted after treatment with diethylcarbamazine

Answer 34

Loa loa

Question 35

Central and W Africa. Spread by the bite of the Chrysops spp flies (deer or mango flies) Adults in subcutaneous tissue (eye)

Answer 35

Loa loa

Question 36

AKA the African Eye Worm

Answer 36

Loa loa

Question 37

Symptoms: Calabar swelling (migratory edema), high eosinophilia, worm in eye Diagnosis: Calabar swelling, microfilariae in blood (drawn during the day) No Wolbachia symbiont

Answer 37

Loa loa

Question 38

Symptoms: Calabar swelling (migratory edema), high eosinophilia, worm in eye Diagnosis: Calabar swelling, microfilariae in blood (drawn during the day) No Wolbachia symbiont

Answer 38

Loa loa

Question 39

Habitat: Cutaneous and subcutaneous tissues Intermediate host (vector): Black flies (buffalo gnats), Simulium species Reservoir host: None Infective form: Filariform larva Mode of infection: Inoculation

Answer 39

Onchocerca volvulus

Question 40

Adults live in subcutaneous nodules Pathology is the host’s inflammatory response to the microfilariae In the eye, microfilariae initially elicit punctate keratitis which can progress to a sclerosing keratitis and blindness

Answer 40

Onchocerca volvulus

Question 41

_____ may cause inguinal lymph node fibrosis and atrophy of overlying skin that leads to 'hanging groin'

Answer 41

Onchocerca volvulus

Question 42

AKA River Blindness Location: Northern S. America, C. &W. Africa Acquired by the bite of the Black fly (Simulium spp)

Answer 42

Onchocerca volvulus

Question 43

AKA River Blindness Location: Northern S. America, C. &W. Africa Acquired by the bite of the Black fly (Simulium spp)

Answer 43

Onchocerca volvulus

Question 44

Adults in subcutaneous nodules, unsheathed microfilariae in dermis Symptoms: Nodules on head (SA), lower trunk (Africa), pruritic skin reactions, “leopard skin”, hanging groin, progressive blindness

Answer 44

Onchocerca volvulus

Question 45

Actually a symptom of larval movement in tissues. | - Visceral will occur in gut tissues, caused by several species, of which ______ are best known

Answer 45

Toxocara spp

Question 46

Cutaneous occurs under skin (often termed “creeping eruption”) and many species of worms may cause this (e.g. _____ and various hookworms)

Answer 46

Ascaris spp.

Question 47

Actually a symptom of larval movement in tissues | May also occur in eyeball

Answer 47

(ocular larval migrans)

Question 48

Ingestion of infective eggs is the root cause of the problem Found wherever dogs and cats are found Puppies can be infected via transplacentally or through breast milk

Answer 48

Caused by Toxocara canis and Toxocara cati

Question 49

Pathogenesis | -Larval forms leave focal site and migrate through tissues to new sites to mature

Answer 49

Visceral Larval Migrans

Question 50

Sites characterized by inflammation, damage, and pruritic skin lesions Long term/deeper infections may have allergic conditions and toxemia reactions Organisms may form granulomas in tissues

Answer 50

Cutaneous Larval Migrans

Question 51

"Creeping Eruptions"

Answer 51

Creeping Larva Migrans

Question 52

Why would you sometimes treat patients with filariasis with doxycycline? A. To eliminate the symbiont Wolbachia B. To reduce the edema swelling C. To treat bacterial superinfections D. To reduce their fever

Answer 52

A. To eliminate the symbiont Wolbachia

Question 53

Which of the blood cells, when in high number, usually is an indication of a parasitic infection? A. Lymphocytes B. RBCs C. Eosinophils D. Neutrophils

Answer 53

C. Eosinophils

Question 54

Bachmans?

Answer 54

Trichinella spiralis Specimen processing – Specimen of choice is muscle biopsy – Skin test: Bachman and others – Blood: ESR, eosinophil count

Question 55

drink unfiltered water with infected copepod?

Answer 55

Dracunculus medinensis

Question 56

Fly bite with adults in subcutaneous, produce sheathed microfilariae

Answer 56

Loa Loa

Question 57

Adult in subcutaneous nodule, produce unsheathed microfilariae

Answer 57

Onchocerca volvulus

Question 58

ingesting infective eggs near cats/dogs, mostly child less than 6 y/o

Answer 58

Toxocara (canis/cati)