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,