FISH TRANSMITTED NEMATODES

By/

AMAL ABDUALBAKI MAOHAMMED

Supervised by/

Prof.Dr: SAFIA SALEH

List of the genera of seafood-borne parasites reported from humans.

 Protozoa  Trematoda (Flukes) o Cryptospoidium o Clonorchis o M.Enterocytozoon o Clinostomum o Giardia o Heterophyes  Cestoda (Tapeworms) o Heterophyopsis o Adenocephalus o Paragonimus o Diphyllobothrium o Opisthorchis o Diplogonoporus o Echinostoma o Ligula o Diplostomum o Spirometra List of the genera of seafood-borne parasites reported from humans.

 Nematoda (Round Worms) o Anisakis o Filaria o Pseudoterranova o Hysterothylaccium o Contracaecum o Philometra o Capillaria o Gnathostoma o Angiostrongylus o Dioctophyma o Echinocephalus o Eustrongyloides Nematoda (Round Worms)

 Several genera of aquatic nematoda from a diverse taxonomic group can cause disease in humans.

 Seafood is the primary source of protein for over a billion people and is the source of over a quarter of the world’s total animal protein. Although seafood is part of a healthy diet, as with any other food, seafood consumption is not risk-free as contaminated with toxins or infectious agents can cause illnesses ranging from mild gastroenteritis to life-threatening syndromes.  Nematoda (Round Worms)

 Over 40 species of parasites associated with seafood, including protozoa, tapeworms, flukes, round worms, and thorny-headed worms, have been reported in humans ,With steady change in the climate this number is expected to increase.  Unlike many other sources of parasitic diseases which are known to be associated with poverty and low income and are an issue in developing countries, seafood-borne parasites are a problem of both developing and developed countries, requiring efforts from all nations and many sectors. Anisakiasis

 Causal Agents

 Anisakidosis or anisakiasis is caused by the accidental ingestion of contaminated seafood containing larval nematodes of the family Anisakidae. Anisakiasis

 Causal Agents

The nematode worms responsible for human infections are generally limited to three genera:

 Anisakis simplex complex (A. simplex sensu stricto, A. pegreffii, A. berlandi (A.simplex C)

 Phocanema, The genus Phocanema has been renamed Pseudoterranova include, P. decipiens complex(P. decipiens sensu stricto, P. azarasi, P. cattani)

 Contracaecum osculatum complex

Life Cycle Hosts

 Definitive hosts include : . Cetacean species for Anisakis simplex . Pinnipeds for Pseudoterranova decipiens . . The bearded seal (Erignathus barbatus) . Gray seal (Halichoerus grypus) are known definitive hosts for Contracecum osculatum complex.  Human-infecting anisakid species are found in a wide variety of marine fish intermediate and paratenic hosts, but are most common in predatory species such as herring, cod, mackerel, and sculpin. Geographic Distribution

 Anisakiasis occurs worldwide due to the global trade of seafood, though the causative agents vary in geographic occurrence in their natural hosts.

 Anisakis simplex complex members occur in broadly both deep sea and coastal environments in the Atlantic Basin, Pacific Ocean, and Alaskan coast  Incidence of human infections is highest in areas where raw fish dishes (e.g. sashimi, ceviche,pickled/marinated fish) are popular.  It is particularly common in Japan, the Pacific coast of South America, and parts of Northern Europe. Pathogenesis

 When the infected raw fish enters the host stomach, gastric enzymes release the parasite into the stomach or rarely, the small intestine. Tissue invasion is facilitated by release of hydrolytic enzymes from the parasite. In humans, the anasakid nematodes die within a few days provoking an eosinophilic granulomatous reaction Clinical Presentation

 Gastrointestinal Manifestations • Untreated anisakiasis may cause persistent inflammatory responses targeting remains of the larvae and can produce symptoms consistent with colitis, appendicitis, cholecystitis, or dyspepsia . • The gastric form manifests usually within 12 hours after consumption of the infected seafood Clinical Presentation

 Gastrointestinal Manifestations • The intra-peritoneal form is characterized by the penetration of the intestinal wall by the larva and migration to the mesenteries, lymph nodes, liver pancreas, ovary and gallbladder, causing a visceral larva migrans-like syndrome with severe eosinophilic granulomatous response. Clinical Presentation

 Gastrointestinal Manifestations  Inflammation induced obstruction of biliary ducts can cause cholangitis and pancreatitis.  Anisakidosis is also an important cause of eosinophilic gastroenteritis.  Occasionally, the larvae are coughed up. Clinical Presentation

 Rare cases of ectopic infection are known, in sites such as the peritoneal cavity, mesentery, esophagus, and tongue. Allergic responses including urticaria were seen Laboratory Diagnosis

 Diagnosis can be made by:  Gastroscopic examination during which the larvae are visualized and removed, or  Histopathologic examination of tissue removed at biopsy or during surgery. Capillariasis

 Causal Agents

Capillariasis is a parasitic infection cause by two species of nematodes :

 Capillaria hepatica, which causes hepatic capillariasis

 Capillaria philippinensis, which causes intestinal capillariasi Geographical disterbution

 Infection with C. hepatica is rare but has been reported worldwide.

 Infection with C. philippinensis is frequently found in the Philippines and Thailand.

 Some cases have been found in other Asian countries, the Middle East (Iran, Egypt), and Colombia, Korea. Mode of infection

 C. hepatica is often found in the liver of animals such as small rodents, monkeys, and can cause cirrhosis in these animal hosts.  When these animals are eaten by larger carnivores, capillarid eggs are ingested and passed through the fecal matter of the carnivore, these eggs become infective in about 30 days and can infect other animals, including humans. Once accidentally ingested by a human, the eggs migrate to the liver and mature to adult worms.  Another route of transmission is through the decomposition of infected animals via eggs in the liver being released into the soil. Mode of infection

 C. philippinensis is found in the tissues of small, freshwater fish.  When humans ingest these raw or undercooked infected fish, larvae migrate to the intestine and mature to adult worms.  Female worms deposit eggs in the intestine, which are released in fecal matter. When infected human fecal matter reaches freshwater, fish can become infected and the cycle continues. Some eggs hatch within the human intestine causing hyperinfection (a massive number of adult worms due to auto infection). Life Cycle Clinical Presentation

 Light infection of C. hepatica worm, often have no signs or symptoms.  With multiple worms and female worms that lay eggs continually, the clinical manifestations of C.hepatica include hepatitis, anemia, fever, hypereosinophilia, and even death. Clinical Presentation

 Intestinal capillariasis initially manifests as abdominal/gastrointestinal disease, which can become serious if not treated because of autoinfection. A protein-losing enteropathy can develop which may result in complications such as dehydration, cardiomyopathy, severe weakness, and death.  In the first recognized outbreak of intestinal capillariasis, the case fatality rate was over 10%. Diagnosis

 C. hepatica can be diagnosed by performing a liver biopsy, needle biopsy, or after death at autopsy.  Analyzing stool samples for C. hepatica cannot be used to diagnose infection.

 C. philippinensis can be diagnosed by taking a biopsy of the tissue of the small intestine or by analyzing stool samples. Prevention

 In order to prevent both types of capillariasis, proper hygiene and disposal of fecal matter is important.  Specific latrines should be used that are both out of reach from animals and will not let fecal matter seep into the water or around the food supply.  Washing your hands with soap and warm water after touching or working with soil and before handling food.  Teach children the importance of washing hands to prevent infection.  Proper fruits washing and vegetables before eating them.  Do not eat raw or undercooked fish. Prevention

 The FDA recommends the following for fish preparation or storage to kill parasites.

 Cooking fish adequately (to an internal temperature of at least 145° F [~63° C]).  Freezing • At -4°F (-20°C) or below for 7 days (total time), • At -31°F (-35°C) or below until solid, and storing at -31°F (-35°C) or below for 15 hours,a • At -31°F (-35°C) or below until solid and storing at -4°F (-20°C) or below for 24 hours. Treatment

 The medications used to treat C. hepatica include Thiabendazole and albendazole. However, C. hepatica is a rare infection and clinical experience is limited. Steroids have been used to help control the inflammation of the liver.  To treat C. philippinensis, medications that can be used include mebendazole (200 mg twice a day for 20 days), and albendazole (400 mg a day for 10 days).  There are medications and treatment options available to cure both forms of capillariasis, but, without treatment, capillariasis can lead to death. Gnathostomiasis

 Gnathostoma spp. are a group of parasitic nematodes that have indirect life cycle, human accidentally infected , in which they can survive but not mature into adults.  Depending on the species, adult Gnathostoma spp. can reproduce in dogs, cats, raccoons, opossums, tigers, leopards, pigs, wild boars, and weasels—these animals are called definitive hosts.  Geographical disterbution

 Gnathostoma spp. are cosmopolitan, but have been reported in humans primarily in tropical and subtropical areas.  Gnathostomiasis is most commonly diagnosed in Asia, particularly in Thailand, other parts of Southeast Asia, and Japan.  The parasite has also been found in other areas, including South and Central America and Africa. Mode of transmision

 Human become infected most commonly by eating undercooked and raw infected freshwater fish,eels(snakes), frogs, birds, and reptiles, swallowing infected water fleas containing larvae .

 The parasite is not transmitted by eating sushi in the U.S. and Western Europe because typically the more expensive saltwater fish are used. signs and symptoms

 The symptoms of gnathostomiasis are thought to be related to the migratory action of the larvae through the body, it moves through the wall of the stomach or intestine and liver.  During this early phase, many people have no symptoms or they may experience fever, excess tiredness, lack of appetite, nausea, vomiting, diarrhea, or abdominal pain. This phase may last for 2 or 3 weeks.  Later, when the larvae moves under the skin, people may experience swellings under the skin that may be painful, red, or itchy. signs and symptoms

 The swellings move around and typically are not pitting, (if the swelling push on the swelling with a finger an indentation is not left behind).  The swellings often begin within 3 to 4 weeks after ingestion of the parasite. but they can occur up to around 10 years after infection. signs and symptoms

 Rarely, Gnathostoma can enter other parts of the body, including the lungs, bladder, eyes, ears, and nervous system, including the brain.  If the parasite enters the eye, it can result blindness.  If the parasite enters a nerve or the spine, it usually results in severe nerve pain, followed by paralysis of the muscle controlled by the affected nerve.  If the parasite enters the brain, it can result in headache, decreased consciousness, coma, and death. Life cycle Diagnosis

 History of eating undercooked or raw freshwater fish, eels, frogs, birds, or reptiles in an area where the parasite is found.  Swellings under the skin that move around the body, eosinophilia.  Recent Special serologic tests for Gnathostoma are available TREATMENT

 There are 2 antiparasitic medications that have been used successfully in patients with gnathostomiasis affecting the skin.  albendazole and ivermectin. Angiostrongyliasis

 Angiostrongylus is a parasitic nematode that can cause severe gastrointestinal or central nervous system disease in humans, depending on the species.  Angiostrongylus cantonensis, which is also known as the rat lungworm, its a parasitic nematode (worm) that is transmitted between rats and mollusks (such as slugs or snails) in its natural life cycle.  Other animals that become infected such as freshwater shrimp, land crabs, frogs. GEOGRAPHICAL DISTERBUTION

 Most cases of infection are diagnosed in Southeast Asia and the Pacific Basin, but the parasite has also been found in Australia, some areas of Africa, the Caribbean, Hawaii and Louisiana

 Causal Agents:  Angiostrongylus cantonensis( rat lungworm), is the most common cause of human eosinophilic meningitis.  In addition, Parastrongylus costaricensis is the causal agent of abdominal, or intestinal, angiostrongyliasis. Risk Factors:

 Ingestion of raw or undercooked infected snails or slugs; or pieces of snails and slugs accidentally chopped up in vegetables, or salads; or foods contaminated by the slime of infected snails or slugs.  It is possible that ingestion of raw or undercooked freshwater shrimp, land crabs, frogs, etc.  Contamination of the hands during the preparation of uncooked infected snails or slugs could lead to ingestion of the parasite. Signs and Symptoms:

  Abdominal Pain  Fever  Nausea  Vomiting  Neck stiffness  Abnormal sensations of the arms and legs  Intestinal inflammation.  Incubation Period:  The incubation period is thought to usually range from several weeks to several months, possibly even up to 1 year. Signs and Symptoms:

 A. costaricensis is usually found in the intestine (especially the ileocecal region) and can cause abdominal pain, fever, nausea and vomiting. Abdominal findings can often mimic appendicitis, and infection is identified after surgical removal of the appendix  In rare cases, the larvae enter the mesenteric arteries found in the abdominal cavity where they mature into adults and can cause arteritis, infarction, thrombosis, and gastrointestinal hemorrhage

 Signs and Symptoms:

 Eggs produced by adult worms lodge in capillaries and cause an inflammatory reaction as they degenerate.  The immune system’s response to the adults, larvae, and eggs can result in a massive eosinophilic inflammatory reaction, with eosinophilic invasion of the intestinal wall and eosinophilic vasculitis.  Intestinal obstruction and perforation can occur, and deaths have been reported.  Recurrent episodes of illness may occur over several months. Most cases resolve spontaneously.  Life cycle Diagnosis

 Travel history to endemic areas.  History of ingestion of raw or undercooked intermediate hosts or possibly transport hosts is a crucial clue as well.  .A diagnosis of A. cantonensis is strongly suggested when symptoms suggest bacterial meningitis but testing reveals eosinophilia either in the blood (>5%) or in cerebrospinal fluid (>10%), elevated protein, and low or normal CSF glucose.  It is important to note, however, that eosinophilia in the CSF and in the blood may not be present on initial presentation or in late stages of infection. The CSF pressure is generally elevated. Signs and Symptoms:

 Recovery of A. cantonensis from the CSF confirms the diagnosis; however, the organism is rarely detected on microscopy as it can adhere to the meninges.  Serologic tests have been developed but are not commercially available.  PCR tests for use with CSF and tissue. Because of the difficulty in making the diagnosis, it is important to rule-out other causes of eosinophilic meningitis.  Neuroimaging studies can be useful as there usually is an absence of focal lesions on CT scan, which helps to distinguish A. cantonensis eosinophilic meningitis from focal lesions which may be seen in neurocysticercosis and gnathostomiasis.  Because eggs are not passed in the feces, a stool examination is not useful for diagnosis. Prevention & Control

 Educating persons residing in or traveling to areas where the parasite is found about not ingesting raw or undercooked snails and slugs, freshwater shrimp, land crabs, frogs, and monitor lizards, or potentially contaminated vegetables, or vegetable juice.  Removing snails, slugs, and rats found near houses and gardens should also help reduce risk.  Thoroughly washing hands and utensils after preparing raw snails or slugs is also recommended. Vegetables should be thoroughly washed if eaten raw. Dioctophymiasis ( Dioctophyme renale )

 Causal Agent  Dioctophyma) renale, the giant kidney worm, is the largest known parasitic nematode infecting humans  adult females can reach over one meter in length.  Human infections are very rare. Dioctophymiasis ( Dioctophyme renale )

 Hosts  Mustelids (particularly minks) serve as the usual definitive hosts for Dioctophyme renale, although infections with adult worms also occur in wild and domestic canids, and raccoons.  Rarely, other mammals, including herbivores and humans can become infected. Dioctophymiasis ( Dioctophyme renale )

 Geographic Distribution  It has broad and likely worldwide distribution in carnivores, although little occurrence in Africa.  Zoonotic infections have been reported from the United States, Iran, India, China, and Indonesia. Life Cycle Dioctophymiasis ( Dioctophyme renale )

 Clinical Presentation

 Most of the earlier reports of dioctophymiasis in humans involved the finding of eggs or adult worms expelled in urine, usually accompanied by hematuria, and sometimes abdominal pain, fever, and eosinophilia. Dioctophymiasis ( Dioctophyme renale )

 Clinical Presentation  Adult worms have been found in the right kidney, left kidney, both kidneys, retroperitoneal space, and liver.  There is one report of a worm rupturing through the body wall (fistula) from an abscessed kidney.  L3 larvae being found in migratory, subcutaneous nodules. Dioctophymiasis ( Dioctophyme renale )

 Laboratory Diagnosis  Identification of eggs in urine, or adult worms which are sometimes spontaneously expelled in urine.  Adults may also be found during laparotomy or hysterectomy (or necropsy) when in the abdominal cavity.  L3 larvae in subcutaneous nodules may be observed in stained tissue sections.  Adult Dioctophyme renale  Both sexes of Dioctophyme renale are large (females 20—100 cm long, 4—12 mm wide; males 14—45 cm long, 4—6 mm wide), bright red, robust nematodes in their adult stages.  Males have a bell-shaped bursa with a single spicule. Kidneys infected with D. renale are often reduced to a hollow capsule surrounding the adult worms.  Posterior end of a male D. renale, showing the bell-shaped copulatory bursa (arrow).  The spicule is not extruded.  One D. renale female (left) and two males (right) extracted from the kidney of a naturally infected dog.  A kidney, which contained three adult D. renale, removed from a naturally infected dog. In renal infections, the parenchyma may be largely destroyed by the adult worms.  Eggs of D. renale in animal tissue, stained with hematoxylin and eosin (H&E). Thank you