sign in sign up
<<
Home , Ancylostoma braziliense, Ancylostoma caninum, Cutaneous larva migrans, Dracunculiasis, Dracunculus medinensis, Gnathostoma

Readings- • Ch. 11 (pp. 290, 291-93, 295 [box 11.1], 304 [box 11.2]) • Lecture 5: Emerging Parasitic Ch.14 (p. 375, 367 [table 14.1]) Helminths part 2: Tissue Nematodes

Matt Tucker, M.S., MSPH [email protected]

HSC4933 Emerging Infectious HSC4933. Emerging Infectious Diseases 2

Monsters Inside Me Learning Objectives

• , migrans (, ): • Understand how visceral larval migrans, cutaneous larval migrans, and ocular larval migrans can occur Background: • Know basic attributes of tissue nematodes and be able to distinguish http://animal.discovery.com/invertebrates/monsters-inside- these nematodes from each other and also from other types of me/toxocariasis-toxocara-roundworm/ nematodes • Understand life cycles of tissue nematodes, noting similarities and Videos: http://animal.discovery.com/videos/monsters-inside- significant difference me-toxocariasis.html • Know infective stages, various hosts involved in a particular cycle • Be familiar with diagnostic criteria, epidemiology, pathogenicity, http://animal.discovery.com/videos/monsters-inside-me- &treatment toxocara-parasite.html • Identify locations in world where certain parasites exist • Note drugs (always available) that are used to treat parasites • Describe factors of tissue nematodes that can make them emerging infectious diseases • Be familiar with and status of eradication

HSC4933. Emerging Infectious Diseases 3 HSC4933. Emerging Infectious Diseases 4

Lecture 5: On the Menu Problems with other

• or Visceral Tissue Nematodes larva migrans • Hookworms of other • Cutaneous Larva Migrans frequently fail to penetrate the (and beyond). • – braziliense (most common- in Gulf Coast and tropics), • spp. , Ancylostoma “creeping eruption” ceylanicum, • spiralis • They migrate through the epidermis leaving typical tracks • medinensis • Eosinophilic enteritis-emerging problem in Australia

HSC4933. Emerging Infectious Diseases 5 HSC4933. Emerging Infectious Diseases 6

1 Visceral Larva Migrans (VLM)

• Caused by juveniles of several of nematodes that gain entry to improper • Larvae begin tissue migration, but become arrested and migrate throughout body • Toxocara canis, • suum No maturation to adults http://www.cdc.gov/mmwr/preview/mmwrht ml/mm5649a2.htm

HSC4933. Emerging Infectious Diseases 7 HSC4933. Emerging Infectious Diseases 8

Toxocara canis T. canis life cycle

• Dog roundworm – Transmitted maternal-fetal • Infects very high % puppies • Distributed worldwide • release massive amounts of that are environmentally stable • Causes VLM, OLM • +inflammatory drugs

HSC4933. Emerging Infectious Diseases 9 HSC4933. Emerging Infectious Diseases 10

Diseases Gnathostoma spp.

• VLM – Larvae invade multiple tissues (, , , • G. spinigerum brain, muscle) and cause , anorexia, weight • Transmitted in , especially and loss, , , ; recently emerged as an important – Death can occur rarely, by severe cardiac, in pulmonary or neurologic involvement. • infected by eating undercooked • OLM or containing third-stage – Larvae produce various ophthalmologic lesions, larvae, or by drinking water containing sometimes misdiagnosed as infected – Often occurs in older children or young adults, • due to migrating, immature worms with only rare or visceral manifestations. • Emerging imported • Dx: For both VLM and OLM, the diagnosis rests • Adults and larvae have numerous spines for on clinical signs, history of exposure to puppies, encysting in host tissue laboratory findings, and detection of Note collar of spines of to Toxocara. adult , used for – Remember, no eggs in stool sticking in host tissue

HSC4933. Emerging Infectious Diseases 11 HSC4933. Emerging Infectious Diseases 12

2 Gnathostoma spp. and Tx

• Within 24-48 h of of larvae, patients may develop fever, , epigastric . • Migration in the subcutaneous tissues causes intermittent, migratory, painful, pruritic swellings (cutaneous larva migrans). • Migration to other tissues (visceral larva migrans) can result in ocular involvement, more serious manifestations such as eosinophilic with myeloencephalitis. • Removal and identification of the worm is both diagnostic and therapeutic. • Tx: Surgical removal or combination with albendazole or

HSC4933. Emerging Infectious Diseases 13 HSC4933. Emerging Infectious Diseases 14

Mexico: An emerging problem (Trichinellosis)

• First case of clinical • Zoonotic infections gnathostomiasis was reported in • Humans are accidental, dead-end hosts Mexico in 1970 • Multiple species of Trichinella infect humans • Over 1,000 cases reported along depending on climate and reservoir hosts Gulf/Pacific Coasts from 1980- • T. spiralis, T. pseudospiralis, T. nativa, T. nelsoni, 1996 T. britovi – 1993-1997: 98 cases in Acapulco • T. spiralis is comopoliltan, most pathogenic • Linked to eating ceviche • Emerging in China, Russia, other European • Mass production and commercial countries distribution of tilapia has been – In 2008, morbidity due to trichinellosis doubled implicated in Russia: 312 cases in 2008 vs. 155 in 2007. – 779 human cases in EU Member States during 2007

HSC4933. Emerging Infectious Diseases 15 HSC4933. Emerging Infectious Diseases 16

Various Life Cycles of Trichinella spp. T. spiralis Life Cycle

Domestic cycle • Domestic pigs are considered the dominant reservoir host, but there are many different typical hosts throughout the world is maintained Sylvatic (wild animal) cycles primarily in rats and other rodents which may • Temperate regions (carrion and live be eaten by other prey): pig, , horse, dog, animals such as pigs and , . • Arctic regions (carcasses): polar bear, walrus, , fox • Tropical regions (carcasses): wharthog, hyena

HSC4933. Emerging Infectious Diseases 17 18

3 T. spiralis Distribution Nurse Cell Complex

• Larvae encysted in striated muscle • Subversion and redirection of host cell activities – Alteration of gene expression of host cell from contractile fiber to cell that nourishes worm – Synthesis of collagen by neighboring fibroblasts encloses nurse cell • Juveniles absorb nutrients while in nurse cell and increase 1mm in 4-8 weeks, infective to hosts • Juveniles enter developmental arrest and live for years • Emerging in China, Russia, other European countries • Calcification of nurse cell and worms by host – In 2008, morbidity due to trichinellosis doubled in Russia: 312 cases in 2008 reactions vs. 155 in 2007. • 779 human cases in EU Member States during 2007 • Lithuania, June 2009: outbreak due to wild boar meat sausages -affected 107 people HSC4933. Emerging Infectious Diseases 20

Disease Trichinosis Dx and Tx

• The first few days of the infection • Dx based on symptoms of stage of life cycle and are characterized by larvae in feces, , other secretions associated with , abdominal pain, • Muscle biopsy for larvae, PCR, vomiting. detection • Pathology is due to migrating • Steroids are used for infections with severe newborn larvae as they randomly symptoms penetrate cells (e.g., brain, liver, • or albendazole can be used to kidney, heart) in their search for treat infections in the intestines striated cells. • Treatment should begin as soon as possible and – Fever and myalgia, bilateral the decision to treat is based upon symptoms, Immature larva periorbital , and petechial exposure to raw or undercooked meat, and from biopsy hemorrhage laboratory test results. • Heavy infection results in – No specific treatment for trichinosis once the generalized edema, larvae have invaded the muscles cardiomyopathies and CNS abnormalities

HSC4933. Emerging Infectious Diseases 21 HSC4933. Emerging Infectious Diseases 22

Prevention Outbreak: Crazy turtles

• In July 2008, four teaching hospitals in northern Taiwan reported 8 patients in • Curing (salting), drying, smoking, or 2 groups with fever, myalgias, and eosinophilia of unknown cause developed microwaving meat does not consistently kill after they shared a common source in May 2008. – Group A: 20 Taiwanese, participated in a festive meal at a Japanese food restaurant, and infective worms. were served raw meat, blood, liver, and eggs of 3 of 5 soft-shelled turtles – Group B: A group of 3 Japanese customers was served the other 2 turtles • Cook meat products until the juices run clear • Extensive serologic testing for helminths by ELISA, hits against Trichinella spp. or to an internal temperature of 170⁰F. • The , clinical features, and laboratory findings in this outbreak were similar to those of other reported trichinosis outbreaks • Freeze less than 6 inches thick for 20 days associated with eating mammals – T. papuae and T. zimbabwensis are the most likely parasites causing this outbreak at 5⁰F to kill any worms. because of their ability to infect mammals and reptiles. • Serum specimens from 6 of the 8 case-patients reacted most strongly to the • Cook wild game meat thoroughly-harder to kill 53-kDa recombinant protein of T. papuae. worms than in pork. • Significance: – Not yet determined how soft-shelled turtles were infected by T. papuae in this outbreak, • so further investigation of the potential infectious source is warranted. Cook all meat fed to pigs or other wild animals. – Further investigations are urgently needed to assess the epidemiology of reptile trichinosis and the human risk for trichinosis from reptiles.

HSC4933. Emerging Infectious Diseases 23 HSC4933. Emerging Infectious Diseases 24

4 This little piggy……

• Egyptian texts suggest that it was common during the middle of the second millennium BC. I don’t each pork as • “ worm” much as I used to- will you? • Eradication efforts have limited areas of disease to many rural communities in , but it is a major public health problem because of dependence upon unprotected water sources for drinking. • Prevents many people from working and leads to food shortages and lower earnings.

HSC4933. Emerging Infectious Diseases 25 HSC4933. Emerging Infectious Diseases 26

D. medinensis Life Cycle Pathology of Dracunculiasis

• Juvenile worms stimulate allergic reaction that causes , usually on lower limbs where juveniles exit • and frequent secondary bacterial infection • Calcified worms and • Paraplegia due to worms in CNS

HSC4933. Emerging Infectious Diseases 27 HSC4933. Emerging Infectious Diseases 28

Dx and Tx of Dracunculiasis Removing adult female worms

Diagnosis • The clinical presentation of dracunculiasis is so typical, and well known to the local population, that it does not need laboratory confirmation. • No serologic test is available Treatment • Local cleansing of the lesion and local application of antibiotics, if indicated because of bacterial superinfection. • Mechanical, progressive extraction of the worm over a period of several days. • 10 day treatment with is not curative, but decreases inflammation and facilitates removal of the worm • Mebendazole has been reported to kill the worm directly.

HSC4933. Emerging Infectious Diseases 29 HSC4933. Emerging Infectious Diseases 30

5 Prevention of Dracunculiasis Dracunculus Eradication Program

• of the disease is most • Originally began at CDC in 1980 common in very remote rural villages and in areas visited by nomadic groups • WHO, UNICEF, , Gates Foundation collaboration has dramatically reduced the of • Drinking water from underground sources free from contamination dracunculiasis • Prevent persons with ulcers from entering • Goal of global eradication by 2009 ponds and wells used for drinking water • In 1986, there were an estimated 3.5 million cases of • Filtration of drinking water to remove Guinea worm in 20 endemic nations in Asia and Africa. copepods • Due to prevention and health education efforts, by the • Treatment of water sources with larvicides end of 2008, there were fewer than 5,000 cases in six to kill copepods nations in Africa: , , , , , • Communities provided with new safe and . sources of drinking water, or have existing dysfunctional ones repaired

HSC4933. Emerging Infectious Diseases 31 HSC4933. Emerging Infectious Diseases 32

6