MIDTERMS CLPARA (LEC) MT3B Trematodes PDF

MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) OUTLINE • Trematodes o I. Orders ▪ A. Order Diplostomida ▪ B. Order Plagiorchiida o II. Classification by Habitat o III. General Characteristics o IV. Developmental Stages o V. Three Patterns of Trematodal Life Cycle o VI. L...

MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) OUTLINE • Trematodes o I. Orders ▪ A. Order Diplostomida ▪ B. Order Plagiorchiida o II. Classification by Habitat o III. General Characteristics o IV. Developmental Stages o V. Three Patterns of Trematodal Life Cycle o VI. Life Cycle of Trematodes o VII. Blood Flukes Phylum Platyhelminthes Class Trematoda CLASS TREMATODA TAXONOMIC CLASSIFICATION (AS OF 2022) CLADE DIGINEA (Most pathogenic flukes are from subclass) Class Trematoda contains a lot The Trematodes are called Trematodes are still flatworms Trematodes are termed as of species that cause neglected flukes and they still belong to but are considered flukes flukes because they are leaftropical diseases around the the Phylum Platyhelminthes. rather than being called shaped rather than being long world. tapeworms. and flat-like tapeworms. ORDERS A. ORDER DIPLOSTOMIDA FAMILY SCHISTOSOMATIDAE (AKA Schistosomes) A family that would have a lot of exemptions to the general characteristics of the trematodes. BLOOD FLUKES (it inhabit the blood vessels) • Schistosoma haematobium • Schistosoma japonicum • Schistosoma mansoni • Schistosoma intercalatum • Schistosoma mekongi B. ORDER PLAGIORCHIIDA SUBORDER ECHINOSTOMATA FAMILY FASCIOLIDAE FAMILY ECHINOSTOMATIDAE • INTESTINAL FLUKE • INTESTINAL FLUKE o Fascilopsis buski o Echinostoma ilocanum o Artyfechinostomum malayanum (Previously called • LIVER FLUKE as Echinostoma malayanum because they have o Fasciola hepatica similarities). o Fasciola gigantica SUBORDER OPISTORCHIATHA FAMILY HETEROPHYIDAE FAMILY OPISTORCHIIDAE (Common name: Heterophyids) • INTESTINAL FLUKE • LIVER FLUKE o Heterophyes heterophyes o Clonorchis sinensis o Metagonimus yokogawai o Opistorchis felineus o Haplorchis taichui o Opistorchis viverrini SUBORDER XIPHIDIATA SUPERFAMILY TROGLOTREMATOIDEA FAMILY PARAGONIMIDAE FAMILY GORGODEROIDEA (Consists of clinically significant species) (Consists of 2 species that are zoonotic in nature and rarely infects humans) • LUNG FLUKE • PANCREATIC FLUKE o Paragonimus westermani (it is the only clinically o Eurytrema pancreaticum (the habitat is pancreas). relevant species here in the Philippines that we • LIVER FLUKE have, but it is actually causing serious trouble o Dicroelium dendriticum (previously known as among the patients). Fasciola lanceolata; resembles a lancet). BLOOD FLUKE CLASSIFICATION BY HABITAT (Habitat – it is the organ or tissue where the parasite resides). INTESTINAL FLUKE LIVER FLUKE LUNG FLUKE PANCREATIC FLUKE Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) (They inhabit the large intestines) • • • • • Schistosoma haematobium Schistosoma japoncium (only endemic in the Philippines) Schistosoma mansoni Schistosoma intercalatum Schistosoma mekongi • • • • • • Fascilopsis buski Echinostoma ilocanum Artyfechinostomum malayanum Heterophyes heterophyes Metagonimus yokogawai Gastrodiscoides hominis (rarely found in the Philippines and rarely causing trouble) (Some of them are inhabiting the bile ducts rather than the liver) • Fasciola hepatica • Fasciola gigantica • Fasciola lanceolata (Dicroelium dendriticum) • Clonorchis sinensis • Opistorchis felineus • Opistorchis viverrine • • • Paragonimus westermani (in the Philippines, we only have this). Paragonimus mexicanus Paragonimus kellicotti • Eurytrema pancreaticum *In some countries they have the mexicanus and kellicotti being more common rather than westermani. GENERAL CHARACTERISTICS Monoecious or hermaphroditic (For one species it has both • Except Schistosoma which are dioecious (but you will sex organs; it can self-fertilize; there is no such thing as see them as a single entity because they are always in male trematode or female trematode unlike roundworms or copula or magkadikit). nematodes). o *There is a male schistosoma and within that male schistosoma nakapasok si female; the female is the one that enters into the male. 2. All appear flat and are leaf-like (the structure is bilaterally • Except Schistosoma which appear elongated and symmetrical meaning if you cut it in half, what you will find cylindrical in shape but is still flat. on the left side will also be found on the right side e.g., if there is a testes on one side, it is also present on the other side). 3. All require 2 intermediate hosts. • 1st → Snail (For a trematode to complete its’ life cycle, there will always be an involvement of the snail as their first intermediate host). • Except Schistosoma → Only one (it will only allow one intermediate host and that one intermediate host or the only intermediate host is the snail). 4. Mode of Transmission (to Definitive Host) → Through • Except Schistosoma → Infects the definitive host by skin ingestion of an encysted larva which we call penetration of cercaria which is a free-swimming larva Metacercaria. that comes out of the snail host. 5. Eggs are operculated. (If this is the egg, you can actually • Except Schistosoma – the egg will break longitudinally it see that there is a line here in which the egg actually opens will force it to break from the egg shell for the schistosome when it is time for the larva to be released from the inside. larvae to be hatched. That structure is called an operculum). 6. Possess 2 suckers (Oral sucker and ventral sucker • Except Heterophyes heterophyes which has 3 suckers [acetabulum]). and the 3rd one possesses a gonotyl/genital sucker. a. *Oral is for nutrition and ventral is intended for attachment. 7. Body is covered by a resistant cuticle or tegument. 8. Possess nervous system. 9. Lack respiratory system. • They breathe through the integument or tegument; that is how respiration occurs. 10. Incomplete alimentary canal (lack coelium); they lack an • Wastes diffuse in the integument. anus. • Oral cavity leads to esophagus that branch to form two intestinal ceca (The opening is the oral sucker; from the oral sucker, it will move just like in humans it is connected to an esophagus and it will branch into 2 intestines or intestinal ceca and will end at the posterior end of the trematodes). • *There is no opening from which the intestines are actually connected for waste disposal. 1. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • 11. Most of the body are taken up by reproductive organs. *The intestinal ceca is placed at the periphery on the side or both ends of the trematodes, the wastes are eliminated on the tegument around the margin of the trematode. • *Tegument – skin of the trematode. • Two testes • Except for Haplorchis → Single Testis. • Testes is located posterior to the single ovary (Trematode has only one ovary and the two testes located at the back but in the case of haplorchis, at the back there is only one testes present). • Except for Eurytrema, Dicrocoelium → Anterior to ovary. The configuration and appearance of the testes will help determine an adult trematode. a. Lobulated or deeply It has a flower petal lobulated. appearance (refer to illustration 1, pic 1). b. Dendritic or branching The appearance is like a root testes of a tree (refer to illustration 1, pic 2). Illustration 1. Parts of a Trematode *The intestines are located at the lateral portion. *From the mouth or oral sucker to esophagus then branched to intestinal ceca with the V shape and it simply ends there without an opening. *The excretory canal is for the release of the eggs not for the waste. *The uterus is very large; it takes up half of the body and the ovary is located just right after the uterus and behind the ovary are the testes. *There are 2 usual configurations of testes: 1. In pairs (magkatabi) 2. Testes in tandem (where one is in front and the other one is at the back). 12. Drug of choice → Praziquantel (for treatment of all trematode infections). c. Globular It is simply round and circular in shape. Vitellaria • Glandular structures lateral to intestines (on both sides). • FUNCTION: Produce shell material for the eggs. It will convert nutrients into molecules needed for making up the shell. • Lead inward to ovary (it is connected to the ovary). o *There is one structure commonly mistaken by students as intestine, which is the uterus. Uterus • Largest organ (dark when seen under the microscope). • Produces thousands of eggs. • Mistaken as the intestine because it looks like this (refer to illustration 1), the one in the middle with a zigzag appearance is actually the uterus. • Except for Fasciola spp. → in which the treatment is Triclabendazole (previously it was bioethanol). DEVELOPMENTAL STAGES 1. EGG • Egg when laid inside the definitive host. • Except PEFF → laying unembryonated egg (what is inside o *Operculated (It will have a structure in which it will the egg are undeveloped cells). open once the larva inside is ready to hatch). • This will only embryonate once the egg reaches water and *Embryonated egg always laid by an adult trematode there is the water will provide nourishment to the egg and will soon already a larva inside waiting to hatch. develop into a larva. PEFF: Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • • • • • • Operculated • Hatches in water (the environment needed if water and soil unlike nematodes). Paragonimus Echinostoma (together with Artyfechinostomum) Fasciola Fasciolopsis Operculated except Schistosomes. Operculum is a cover of the egg where miracidium can easily escape when it is time for it to hatch. • Except CHOD → hatches inside the snail host or the 1st intermediate host. CHOD + Eu: • Clonorchis • Heterophyids • Opisthorchis • Dicrocoelium • Eurytrema Illustration 2. Egg of Trematode *Operculum is the cup-like structure, once an egg or larva inside is ready to move out, this will open but for schistosomes, the egg will break as the larva forces itself to move out. 2. MIRACIDIUM (It is what is inside the egg and what will hatch in the egg) • Released in water from the egg or inside the 1st intermediate • Except in CHOD, Eurytrema. host. • Infective stage to the 1st intermediate host by penetration of the soft part of the snail not the shell. • Develops into SPOROCYST and then into REDIA (once it enters the snail host). • The infective stage to the 1st intermediate host is the egg which contains miracidium, before the egg can hatch it needs to be inside the 1st intermediate host. • Therefore, the infective stage to other trematodes is the embryonated eggs. You get infected when you ingest the embryonated egg. Illustration 3. Miracidium Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) This is the appearance of the miracidium (Illustration 3) roughly triangular in shape and is covered by a lot of hair-like structures; it is ciliated. They do not have a mouth or oral sucker so they cannot eat and they need to find a host as quickly as possible because after 8 – 12 hours, they will die since they cannot get nutrients for themselves. That scenario is one link which can prevent parasitism of trematodes and eliminate the first intermediate host, however it is impossible to do. Once you eliminate snails, it will cause an ecological imbalance; that is why you need to find other ways to do this. • Sporocyst – undifferentiated mass of cells and these cells are contained inside elongated sacs. o *It is inside the 1st snail intermediate host and undergoes asexual reproduction to form more sporocysts or move to the next stage redia. o *Not all trematodes will possess a sporocyst stage and one example is an Echinostoma ilocanum. o *Echinostoma ilocanum lacks a sporocyst stage therefore, the miracidium readily develops as a redia not a sporocyst. Illustration 4. Sporocyst • NO REDIA in Schistosomes – it’s just generating more sporocysts. o *Redia contain more developed cells and inside the sac, you would even see a formation of cercaria already, that cercaria will have oral suckers and can take nutrients by itself. o *It has a saclike intestine, uterine pore, and that is where the cercaria will be released. These cell structures are developing cercaria. Illustration 5. A microscopic image of Redia • Once the cercaria is ready for release, it would move out the uterine pore and ultimately, it will move out the 1st intermediate host, going out of the snail and going back to water. CERCARIAL RELEASE MECHANISM • It is the process that happens when a freshwater snail would move to the water. Normally, we don’t see snails often going to the water, but they get infected either by penetrating a miracidium or by ingesting an embryonated egg that has a parasite. After that, it moves out the water to find some good environment and later in the evening, it goes back, when it goes back to the water, there could be cercaria already that detects moisture from water and swims out of the 1st intermediate host. Therefore, the snail has passed another developmental stage and that is the cercaria. 3. CERCARIA (Looks like a sperm cell and is freely swimming in the water; not all cercariae are the same) TYPES Microcercous (Family Small tail; has a stylet (on its’ Troglotrematidae) oral sucker, it’s like a spine/single spine) found in paragonimus. Echinostome Oral sucker has spines (many (Echinostomatidae) spines like a crown of spines). Gymnocephalus (Fasciolidae) Big, round to oval head, no stylet the oral sucker. Pleurolophocerous (Opistorchiidae and Heterophyidae) Dorsal or dorso-ventral fin (either at the back, or front and back but middle none). Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • • • • • • Final stage found in the 1st intermediate host (released into the environment; can recover either in 1st IH or the water). Released from the 1st intermediate host into the water. Infective to 2nd intermediate host by means of penetration except for Schistosomes because they don’t have a 2nd intermediate host. Schistosome cercariae is the one infective to the definitive host (man) – since there’s no 2nd intermediate host, therefore it follows that the cercaria will infect the definitive host. Terminal intramolluscan larval stage is the one that emerges from an infected snail host. The 2nd intermediate host may be a snail, a fish, or a crustacean usually a crab. Parapleurolophocerous (Haplorchis) Xiphidiocercous (Dicrocoelium) Furcocerous (Schistosomatidae) Fin extends all throughout the tail, evident ventral sucker. *Common characteristics for the pleuro and parapleuro are the 2 eye spots found on the head that look like an eye. Elongated head with stylet (it can be mistaken with megalurous cercaria; same with big elongated head but it is found on other trematodes that does not infect man). Fork-tailed (2 small structures in the tail). Illustration 6. Cercaria ILLUSTRATIONS/DIAGRAMS Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) A – C (Pleurolophocercous) D – E (Parapleurolophocercous) Illustration 7. Types of Cercaria A – Echinostosome (green head; crown of spines). B – Microcercus (small tail not even half of the body). C – Pleurolophocercous (has fins). D – Xiphidocercous cercaria (has stylet like a cone). E – Parapleurolophocercous (has fins all over). F – Gymnocephalus cercaria (big round head). G – Furcocercous (found on other trematodes called strigean furcocercous cercariae with long extended fork-tail; curved upwards and whole structure looks like an anchor). H – Furcocercous (with short extended fork-tail; for Schistosomes). Illustration 8. Types of Cercaria A – Microcercus B – Echinostome (crown of spine) C – Furcocercous D – Pleurolophocercous E – Parapleurolophocercous F - Xiphidiocercous Illustration 9. Types of Cercaria • Schistosomule – if the cercaria penetrates the skin of a human, it will shed its’ tail and will only have the head of a cercaria that is a schistosomula and eventually will mature into an adult worm. • 4. METACERCARIA (Infective to the definitive host) Encysted larva found on tissue of 2nd intermediate host. • NOT FOUND ON Schistosomes. 5. ADULT (If you ingest the metacercaria, it will encyst and mature) Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • Leaf-shaped and bisymmetric except for Schistosomes (cylindrical) In Schistosomes, the thick part is the male and inside the male is the female (Illustration 10). The one on top is the trematode (Illustration 10). Has 2 – 3 suckers except heterophyids which has 3. They can be differentiated by the suckers, testes, ovaries, and intestines. Dorsoventrally flat. • • • • • Illustration 10. Adult Trematode and a Schistosome Take note of the ff. to identify the fluke: • Intestinal Ceca (Wavy, Simple, Branched) • Oral and Ventral Sucker (which of which is larger) • Presence or absence of gonotyl • Morphology and arrangement of testes and ovary • Location of testes (anterior or posterior) • Vitellaria location (anterior, posterior, middle). THREE PATTERNS OF TREMATODAL LIFE CYCLE • Cercaria infects the definitive host and lacks 2nd intermediate host. 2. Life Cycle of Flukes that lay Unembryonated Egg • Egg embryonates and hatches in water to release miracidium that is infective to 1st intermediate host. 3. Life Cycle of Flukes that lay Embryonated Egg • Egg hatches inside the first intermediate host (snail). • The adult lay embryonated egg and passed to the feces or stool of the definitive host once it reaches the water, it will not hatch and get ingested by the 1st intermediate host then inside the snail miracidium will be released. 1. The Schistosome Life Cycle 1 2 3 LIFE CYCLE OF TREMATODES It always begins with an egg, eggs are passed • Except for PEFF → UNEMBRYONATED, DEVELOPS EMBRYONATED and OPERCULATED from the stool of IN WATER. DEFINITIVE HOSTS. • Except for Schistosomes → NON-OPERCULATED o *Once passed in the stool, it will be carried to the water and usually trematodes would love freshwater not salty water like in the ocean. o *Unembryonated egg will immediately embryonate once found in water and the miracidium is ready to hatch. Miracidium escapes the operculum and swims freely in • Water and Light seems to be the stimuli for the water. miracidium release. • For Schistosomes, they longitudinally break the egg. • For COD → Egg does not hatch until it is ingested by 1st intermediate host. o *Once 2 stimuli are actually satisfied, miracidium will move out the operculum and the egg will break releasing miracidium in water, it freely swims until it finds the 1st intermediate host. Miracidium infects the 1st intermediate host, a snail, via • For COD only → Miracidium escapes the operculum skin penetration except for Clonorchis, Heterophyes, inside the snail host. Opistorchis, and Dicrocoelium where the infective stage • Miracidium becomes sporocyst. is the ingestion of embryonated eggs, where miracidium • Two generations of sporocysts occur inside the snail. is released inside the snail (host). • 2nd Generation matures into a Redia except in Schistosomes, no Redia stage. • Redia matures into cercaria. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) o 4 Cercaria leaves the snail host and swims freely in the water EXCEPT for schistosomes. 5 Cercaria infects 2nd intermediate host via encyst upon ingestion to become metacercaria EXCEPT for schistosomes. 6 Cercaria encysts to become metacercaria in the tissue of the 2nd intermediate host. 7 Humans and other Definitive Hosts get infected by eating raw 2nd Intermediate Host. The metacercaria is ingested and exists in duodenum to release an adolescent cercaria which either: 8 Eggs will be passed into the stool, EMBRYONATED and the cycle repeats… usually *The one with no sporocyst is Echinostoma ilocanum. • After mature cercariae in redia, it will be released from the uterine pore and will swim out to water again, the cercaria is freely swimming in water until it finds a different host. • Dicroelium spp. → Cercariae are shed as slime balls in land (plants) when it is raining. • The 2nd intermediate host is like a snail or fish while in a schistosome it will find a human and cercaria will sense the signal of a definitive host of different chemicals on the skin and swim and penetrate the host. o *This is where the cercaria infects the DEFINITIVE HOST by penetration. a. Snail Host → Echinostoma b. Aquatic Plants → Fasciola, Fasciolopsis c. Crab → Paragonimus d. Freshwater Fish → Heterophyes, Clonorchis, Opistorchis, Haplorchis, Metagonimus e. Ant → Eurytrema, Dicroelium f. Grasshopper → Eurytrema • For Schistosome, Cercaria sheds its’ tail to become Schistosomule and is ready to mature into an adult worm. o *For other trematodes, it encyst as metacercaria and for schistosomules, it completes its’ life cycle in humans. a. Will enter the circulation, reach the heart and lungs (Blood Fluke) and redistribute in the liver where it will mature. The adult will then migrate to its’ final destination. b. Will penetrate the peritoneal cavity and reach the pleural cavity and eventually the lungs (Lung Fluke) where it will mature. c. Will ascend the biliary tract through the Ampula of Vater (Liver Flukes). d. Mature in the small intestine and occasionally move to the bile duct or large intestines (Intestinal Flukes). e. Migrate to the pancreas (Eurytrema). a. _________________ → Urine b. _________________ → Sputum BLOOD FLUKES CHARACTERISTICS 1 2 Inhabit the blood vessels (adult worms). Lay non-operculated egg with spine (may be terminally located or laterally located or small inconspicuous knob). Illustration 11. Non-operculated Egg 3 4 Lack redia and metacercaria stage. Infective Stage: Cercaria Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) 5 6 7 8 9 • MORE SPECIFICALLY, Furcocercous cercaria. • Described as infective stage of blood fluke; fork-tailed. • Found in freshwater. MOT: Skin penetration. This would require only 1 intermediate host (snail). Pathology is caused by eggs. Schistosomule (may be a male or female) matures in the liver (where adult worms mate and become copula). • *One type of cercaria will produce one type of sex. Dioecious (adult worms are found together; in copula). Illustration 12. Adult Trematode 10 11 • *The male is the bigger one and has a banana shape; female is the thin and longer one. Males are thicker compared to females. • Possesses gynecophoral/gynecophoric canal – where female enters or puts itself inside the male host. Females are longer than males. LIFE CYCLE OF SCHISTOSOMES 1 2 3 4 5 The eggs that is laid are embryonated. It will hatch in the water with 2 to 4 hours within contact together with the stimulus of light and they will only hatch in clean fresh water because they are not able to tolerate salt water (anything greater that 0.7 % na pagka-alat ng water will render the egg useless) and it will destroy the egg rendering it unable to hatch, it will kill the larva inside. The miracidum will hatch from the Egg. • It is phototactic - loves light. It swims freely in the water until it finds the host, which are snails (intermediate hosts). It penetrates the soft part of the snail and then inside the snail, it will develop into sporocysts, multiple asexual reproduction occurs until a cercaria will be formed. It does not have a redia. Once the snail goes back into the water, the cercaria will be released and it will swim freely in the water. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) 6 7 8 9 10 The cercaria sensing signals from the lipid of the skin of humans. Man gets infected usually when you go to the river barefooted, when you step on the river, the lipids is in your skin (in your foot) will be sensed immediately by the cercaria and they will immediately swim towards you and penetrate your skin. Once they penetrate, they will shed their tail to become a schistosomule. The schistosomule will reach your circulation. • Remember, it penetrated your skin and it will go to your capillaries, and from the capillaries it will be brought back. After your heart pumps blood, the oxygenated blood will move to the different tissues in your circulatory system. The blood will be taken back to the heart for re-oxygenation. Now, the schistosomule will move to that flow and that is why it undergoes heart-lung migration because the blood that comes from back to the heart needs to be oxygenated by your lungs and then ultimately, it will be carried inside the liver. The schistosomule will become an adult worm. The adult According to Belizario, this one is being practiced in areas worm will only move out of the liver once they are paired, where it is endemic and that is usually in the Visayas region. meaning to say if the female or the male is paired with the opposite sex. And once they are in copula, they will migrate to their final habitat, their true habitat which is the blood vessel. It differs according to species; after being in copula in the liver, they will move to the blood vessels and they will lay eggs. After laying, eggs will be passed into the stool or in the urine. For urine that is only true for haematobium, sometimes Japonicum is being passed in the urine but it’s always a contaminant. The one that is really found in urine is haemotobium, cercaria can actually be seen in the water by passing a beam of light (refer to photo on the right). SCHISTOSOMIASIS • If someone wants to cross a river, they will have to check first if there are cercaria swimming in that water. o Make sure that you are wearing very resistant shoes or protective material in order for the cercaria to not penetrate. o Know or use the correct height of boots. o If your thigh is not covered enough, the cercaria can penetrate any part of the skin. • This disease is also commonly known as snail fever; there are different manifestations. • Acute schistosomiasis – swimmer’s itch. o Caused by the cercaria that penetrated the skin. o It is a petechial hemorrhage with pruritus and edema. o Rashes are edematous in nature due to the penetrating cercaria; your body (particularly the immune system). ▪ Pruritus is due to your allergic reaction to the foreign cercaria. o This one is localized and it will persist for up to four days. Afterwards, you may become asymptomatic for a period. The skin penetration of cercaria has different mechanisms: • First Exposure: Swimmer’s itch will happen. • However, if you have already been exposed to a schistosome and have been treated before you already have antibodies, your rashes might even be worse due to antibody dependent-mediated or cellmediated cytotoxic assaults. • Afterwards, after four days have passed, the schistosomula might have already reached your liver and then you may be asymptomatic. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) KATAYAMA FEVER OR SYNDROME ADULT MORPHOLOGY EGGS • Three weeks after infection, you might develop a transient allergic and toxic manifestation of schistosomiasis called as your Katayama fever or syndrome. • It is simply acute schistosomiasis as well but not due to the cercaria. o It is caused by when the worm started or starts to lay eggs and your body reacts to the eggs produced by the worm. • A serum sickness-like reaction. • Similar to vaccination; you can develop a fever, rash, myalgia, body pain. • It is a systematic hypersensitivity reaction due to the eggs. • Generalized fever that is commonly seen in patients usually infected with Schistosoma japonicum. MALE • Appearance of your adult schistosomes, oral sucker and the acetabulum or ventral sucker is evident. • It does NOT have a gonotyl, which is only present in heterophyids. • Banana-shaped = male schistosomes. • Thicker and has a gynecophoric canal opening in which the female attaches itself or inserts itself. FEMALE The female would have a very dark body because it contains the eggs and it may produce thousands of eggs. Components: • Eggshell; • Von lichtenberg’s envelope – margin of the miracidium. • Subshell area – the space in between is the spine. • Terminal spine – always at the end which has tapering. • Lateral spine – sides, near the bulge. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • MIRACIDIUM HATCH • • The miracidium hatches by bursting and breaking the egg. o It would still break Von lichtenberg’s envelope. o It’s the one moving; it will struggle until such time. The movement is very fast (in water). The miracidium even grows bigger as it breaks. EGG MORPHOLOGY S. HAEMATOBIUM Vesical blood fluke Veins of the vesical and pelvic plexus. Elongated with terminal spine. INTERMEDIATE HOST Bulincus truncates PATHOLOGY Urinary Bilhazariasis Egyptian Hematuria COMMON NAME HABITAT GENERAL CHARACTERISTICS • • • • • • • S. JAPONICUM Oriental blood fluke Superior mesenteric veins of small intestine. Spherical with a small (inconspicuous) knob. Oncomelania hupensis quadrasi. Oriental Schistosomiasis Asian Intestinal Bilharziasis S. MANSONI Manson’s blood fluke Inferior mesenteric veins of colon and rectum. Elongated with lateral spine. Biomphalaria glabrata. Intestinal Bilharziasis Swamp Fever SCHISTOSOMA HAEMATOBIUM First clinically significant schistosome. COMMON NAME: Vesical blood fluke. Sometimes, it may also be called as your Nile blood fluke. o First documented in Egypt along the rivers of Nile. o Probably the oldest known trematode being accounted probably even in the Ebers papyrus. o Very rampant in ancient Egypt because they use the water from the Nile River for all of their activities. Habitat: Veins of the vesical and pelvic plexus. o Around, even in your bladder; one being passed in the urine, because the veins are proximal to your urinary system. Intermediate Host: Bulincus truncatus. Egg Morphology: Elongated with a terminal spine. Can be seen in urine and stool (if contaminated with urine). LIFE CYCLE • • • It’s always the same; from egg up until the schistosomule and up to the liver. Once they pair in the liver, the adult fluke will migrate to the venous plexus of the bladder or veins of the vesicle and pelvic plexus and will lay eggs. These blood vessels are connected, like in your urinary system and they will penetrate the barriers and will pass to the urine. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • • They do not penetrate the kidneys, but penetrate the walls of the bladder. The cercaria will be released in the late morning and into the early afternoon from 11AM to 1:30 PM, the cercaria from the snails are released at that time. However, the penetrative activity of the cercaria is actually more active from 5PM onwards. o Released in the morning, but will hide after the sun goes down. The cercaria will go back to the surface of the water to find the definitive host. o Unlike the Schistosoma japonicum, the cercaria is released late in the afternoon and early in the evening because the snail is more active during the evening. o Haematobium – different because the cercaria are released from 11AM to 1:30PM and its’ penetrative activity occurs from 5PM onwards. • The passage of the egg happens more frequently during the day so probably because the adult fluke would lay eggs only during the evening, in the morning, the eggs might have reached the bladder and can be passed in the stool. • Eggs may be deposited from the walls of the bladder and the walls of the uterus because the veins, where the adult worms resides there, are very near to the uterus. • It may even deposit to the vaginal wall and it may even deposit to the prostate and once that happens, problems along these different organs in the body or structures such as your vaginal wall will manifest different symptoms. MALE • 15 mm long, 0.9 mm thick. • Covered by thick TUBERCULATE tegument when seen under the electron microscope; what differs it from other male schistosoma. • (Very) small oral sucker, more prominent ventral sucker. • Gynecophoral canal will be in between the ventral suckers and the rest of its body. FEMALE • 20 mm long, 0.25 mm thick. • Longer than male. • Male because it looks like a ADULT MORPHOLOGY banana and it’s very thick. PATHOLOGY ASSOCIATED DISEASE OR Urinary Schistosomiasis • Aside from being called Snail fever, it is also called as bilharziasis, probably from the discoverer of the schistosome disease. • Common in Nile river. o Egyptian hematuria ▪ First manifestation is Terminal hematuria. ▪ Void first a very clear urine, at the end of your urine, you will find streaks of blood. ▪ Common among Egyptians. ▪ Endemic in Africa. o Bladder Squamous Cell Carcinoma ▪ Can be found in heavily infected patients. ▪ When schistosoma haematobium is too heavy for the body (very heavy worm burden). ▪ Related to chronic infection, many eggs have been passed. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) ▪ ▪ ▪ Can elicit cells and can cause bladder cancer carcinoma. Eggs are carcinogenic in the squamous cell of the urinary bladder. Most common site of infection for women is the urethral cervix. Nephrotic Syndrome • May occur due to immune complexes. • When the antibody reacts to the eggs (antigens). • Will form aggregates and can cause nephrotic syndrome. Obstructive Uropathy • High egg burden (it can no longer pass the urinary tract). GENERAL CHARACTERISTICS • • • • • • • • • LIFE CYCLE • • ADULT MORPHOLOGY • • • • SCHISTOSOMA JAPONICUM Endemic in the Philippines and usually in the Visayan region. Common Name: Oriental Blood Fluke Confined to East Asia and Southeast Asia. Habitat: Superior mesenteric veins of small intestines. 1st Intermediate Host: Oncomelania hupensis quadrasi Endemic to the Philippines, China, and Indonesia. Used to be endemic in Japan but is now eradicated Eggs are Spherical with a small (inconspicuous) knob. MOST VIRULENT blood fluke ⤳ It lays the most number of eggs 10,000 eggs per lay Differs in migration. Once it reaches the and pairs with each other, it will move to the superior mesenteric veins of the small intestines and because it is around the intestines, the eggs will be shed in the stool. Slenderer than S. haematobium. Still banana shaped. Oral and ventral suckers are seen Gynecophoral canal - space. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) PATHOLOGY ASSOCIATED DISEASE • OR • • GENERAL CHARACTERISTICS • • • • • • • LIFE CYCLE • ADULT MORPHOLOGY • • Oriental Schistosomiasis o Highly associated with Katayama Fever. o Affects the intestines because it lives in the blood vessels near the intestine. o Since it is an Oriental Schistosomiasis, it was given a name as Asian Intestinal Bilharziasis. Hepatosplenic Schistosomiasis o Most common form of chronic schistosomiasis japonicum. o Occurs because it resides in the superior mesenteric veins and it is closer to the liver. o Liver can be damaged by eggs. o Diagnostic: Clay-pipe stem fibrosis. Other forms o Intestinal Schistosomiasis - superior mesenteric veins. o Pulmonary schistosomiasis - heart lung migration. o CNS Schistosomiasis - maliligaw sa brain. SCHISTOSOMA MANSONI Manson’s blood fluke. Habitat: Inferior mesenteric veins of colon and rectum. Morphology: Elongated with Lateral Spine. Intermediate Host: Biomphalaria glabrata Intestinal Bilharziasis. Smallest among the SCHISTOSOMA spp. More common in Africa and Latin America. o The migration of people from Puerto Rico to New York is notable to be a cause for future establishment of S. mansoni infection of North American snails. After copulating in the liver, it will migrate to the inferior mesenteric veins via the hepatic portal vein and then it will lay eggs there and it will be passed in the intestines. Thicker than japonicum. Rougher. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) PATHOLOGY ASSOCIATED DISEASE Schistosoma intercalatum OR • • • • • • • • Schistosoma mekongi • • • • • • Intestinal Bilharziasis Called as Swamp fever in Africa and Latin America. Blood Flukes (not common but emerging) Eggs in stool - an intestinal blood fluke. J-shaped or Curved Terminal Spine and possesses an equatorial bulge; hour glass appearance. Eggs are ACID FAST! Manifests as Intestinal. Schistosomiasis - No hepatomegaly. Occurs in Western and Central Africa. Eggs in stool. Resembles S. japonicum but smaller. Intermediate Host: Neotricula aperta. Produces milder disease. Reservoir host: Pigs. Found in Mekong River basin in southern Laos and Cambodia. PREVENTION, CONTROL, AND TREATMENT Community Health Education • Establishing a culture of safety and prevention. • Conduct with the element of Cultural Sensitivity. Strengthen the Diagnostic Competency of Primary Healthcare Workers in Endemic Areas. Snail Control • Environmental Control Measures o Remove Breeding Sites. Treatment: Praziquantel. • • FLUKES THAT LAY UNEMBRYONATED EGG Paragonimus, Echinostomids, Fasciola, Fasciolopsis Adult worms lay unembryonated egg. Egg is passed in stool and embryonates in water. REPRESENTATIVE ORGANISMS Lung Flukes Paragonimus spp. Intestinal Flukes Echinostoma spp. Fasciolopsis spp. Liver Flukes Fasciola spp. (Lays unembryonated egg). COMMON NAME Lung Flukes: Paragonimus westermani Oriental Lung Fluke Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) HOSTS • • Brotia asperata Antemelania dactylus. 2ND INTERMEDIATE HOSTS (CRABS) • • Sundathelphusa philippina. Old Name: Parathelphusa grapsoides. 1st INTERMEDIATE (SNAILS) Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) Paragonimus westermani DEFINITIVE HOSTS ACCIDENTAL HOSTS 1ST IH 2ND IH DEFINITIVE HOST LIFE CYCLE Felines and canines. HUMANS. INFECTIVE STAGE Miracidium Microcercous cercaria (short-tailed cercaria). Metacercaria • • • • • • EGG MORPHOLOGY Embryonated egg embryonates in the water. When light hits the water, the miracidium will find the intermediate host (snail): Brotia asperata and Antemelania dactylus. Once inside, it will become Sporocysts, then Rediae, then Cercariae. The microcercous cercaria will swim until it finds a crab (Sundathelphusa philippina) and would encyct on the flesh part. Once a person ingests the uncooked/raw crab, the metacercaria would be moving towards the duodenum. The encysted metacercaria would move and penetrate the peritoneal cavity, then the plural cavity; then reaches the lungs. • Operculated and Unembryonated. o Stool o Sputum • Wide, Flattened Operculum • Possess Thickened Abopercular. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • • ADULT MORPHOLOGY • • • Coffee -bean appearance. In lung biopsy. o Seen in pairs or in threes. Testes - posterior region o Deeply lobulated. o In opposite sides. Wavy Intestinal Ceca Ovary - post acetabular region o Lobed o Anterior to testes. Paragonimus westermani can be diploid (requires another pair) or triploid (seen as a single being, more capable of self-fertilizing). PATHOLOGY TREATMENT AND TREATMENT PREVENTION AND CONTROL • • • • • • • • • Lung Flukes Misdiagnosed as Pulmonary Tuberculosis Chest X-ray will show patchy infiltrate with nodular cystic shadows or calcifications. MAY BECOME ERRATIC & INFECT CNS. o Cerebral paragonimiasis. Praziquantel 7 drug of choice. Bithionol - best alternative. Community Health Education. o Cook seafoods properly. o Challenge: Break local traditions. Eating raw crabs o Kinigang, a native Bicolano dish made from crab meat (usually raw) with coconut milk. o Kinilaw (Philippine ceviche) using crab meat (soaked in vinegar). Other countries: o Drunken crab dish in China, Marinated in wine. o Soy Marinate Crab dish in Korea (Ganjang gejang). o Nam Prik Proo (crab and chili paste) in Thailand. o Eating sashimi from: ▪ Wild Boar Meat; ▪ Bear Meat. Strengthen diagnostic competency of local health staff. Intestinal Fluke: Echinostomid Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • • • • • Adults are characterized by a collar of spines around the oral suckers. Cercaria is called an Echinostome Cercariae. o contains colorous spines Two important species in the Philippines: o Echinostoma ilocanum o Artyfechinostomum malayanum Fluke that lay unembryonated eggs. Note: o Don’t use HPO and OIO for trematodes because it is big enough already, unless you’re observing the eggs. HABITAT DEFINITIVE HOSTS FIRST INTERMEDIATE HOST SECOND INTERMEDIATE HOST 1 (DIAGNOSTIC STAGE) 2 3 4 5 6 7 GENERALIZED INFORMATION Small intestine. Rats, birds (duck), also humans. Snail. Snail, frog. • For the Philippines: Snail. GENERALIZED LIFE CYCLE Unembryonated eggs are passed in feces of infected definitive hosts and develop in water. Miracidia usually take about 3 weeks to mature before hatching. Miracidia swim freely and penetrate the first first intermediate host (snail). Development in the snail tissue occurs 4a The intramolluscan stages include a sporocyst stage. 4b Develop into one or two generations of rediae. 4c Develop into cercariae, which are released from the snail. The cercariae may encyst as metacercariae within the same first intermediate host or leave the host and penetrate a new second intermediate host. Free-swimming cercariae invade a second intermediate host (snails or frogs). The definitive host becomes infected after eating metacercariae in infected second intermediate hosts Metacercariae excyst in the duodenum and adults reside in the small intestine (for some species, occasionally in the bile ducts or large intestine). COMMON NAME 1ST INTERMEDIATE HOST Intestinal Fluke: Echinostoma ilocanum Garrison’s Fluke. Snails: • Gyraulus convexiusculus; • Hippeutis umbilicalis. Image: Gyraulus convexiusculus Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) 2ND INTERMEDIATE HOST Snails: • Pila luzonica (kuhol) o Where the cercariae metacercariae. • Vivipara angularis. will encyst as the Image: Pila luzonica DEFINITIVE HOSTS Humans INFECTIVE STAGE Miracidium • No sporocyst stage; • Becomes a mother redia immediately. 2ND INTERMEDIATE HOST Echinostome cercaria. DEFINITIVE HOST Metacercaria. EGG MORPHOLOGY • Operculated and Unembryonated o Dot-like operculum o Thickened abopercular end. • Indistinguishable to Fasciola and Fasciolopsis if large o Usually small; o Straw colored. ADULT • Tapered posterior end; MORPHOLOGY • Oral suckers surrounded by circumoral disk with crown of spines. o 49-51 collarettes; o Crown of spines only seen in LPO. • Globular testes in tandem. • Ovary anterior to testes. • Uterine coil between ovary and ventral sucker. • Plaque like scales. 1ST INTERMEDIATE HOST COMMON NAME 1ST INTERMEDIATE HOST Intestinal Fluke: Artyfechinostomum malayanum None. Snails -- Gyraulus convexiusculus. 2ND INTERMEDIATE HOST Snails • Lymnaea cumingiana (Birabid) o Small; o Normally found in rice fields. o Very common in Isabela and Tarlac. DEFINITIVE HOSTS Humans 1ST INTERMEDIATE HOST 2nd INTERMEDIATE HOST Miracidium. INFECTIVE STAGE Echinostome cercaria. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) DEFINITIVE HOST Metacercaria. EGG MORPHOLOGY • ADULT MORPHOLOGY • • • • PATHOLOGY • DIAGNOSIS TREATMENT PREVENTION CONTROL • • • AND Similar to Echinostoma ilocanum. o More golden in color; slightly larger. More rounded posterior end. 43-45 collarette of spines. Deeply Lobulated Large Testes (6-9 lobes) o In tandem. Rounded Ovary. Intestinal Flukes: Echinostoma spp. Echinostomiasis o Intestinal Infection ▪ Inflammation at the site of attachment. o Heavy Infections: ▪ Diarrhea, (Bloody); ▪ Abdominal Pain; ▪ Intoxication: (metabolites). Microscopic identification of eggs in the stool. Drug of choice: Praziquantel. Community Health Education o Challenge: Breaking local customs. ▪ Eating raw snails. ▪ Birabid is more commonly eaten raw than kuhol (Isabela and Cagayan Province). Intestinal Fluke: Fasciolopsis Fasciolopsis buski • Largest trematode-infecting man. COMMON NAME Giant Intestinal Fluke. 1ST INTERMEDIATE Snails: HOST • Segmentina trochoideus • Hippeutis cantori 2ND INTERMEDIATE Aquatic Plants: HOST • Trapa bicornis (Water caltrop) • Eliocharis tuberosa (Water chestnut) • Ipomea obscura (Kangkong). DEFINITIVE HOSTS Humans RESERVOIR Pigs INFECTIVE STAGE 1ST INTERMEDIATE Miracidium. HOST Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) 2ND HOST INTERMEDIATE Gymnocephalus cercaria. DEFINITIVE HOST Metacercaria • That has encysted in the aquatic plant • Note: o Be very careful if a dry aquatic plant is seen. o Do not make it wet again with similar water where it came from. o Drying kills metacercaria. o Making it wet again could make it infested by another cercaria and encysted again by a metacercaria. LIFE CYCLE 1 Immature eggs are discharged into the (DIAGNOSTIC intestine and stool. Eggs become STAGE) embryonated in water. 2 Eggs release miracidia. 3 Miracidia invade a suitable snail intermediate host. 4 In the snail the parasites undergo several developmental stages (sporocysts to rediae to cercariae). 5 The cercariae are released from the snail and encyst as metacercariae on aquatic plants. 6 (INFECTIVE The mammalian hosts become infected by STAGE) ingesting metacercariae on the aquatic plants. After ingestion, the metacercariae excyst in the duodenum. 7 Attach to the intestinal wall. There they develop into adult flukes (20 to 75 mm by 8 to Adults have a lifespan of about one year. 20 mm) in approximately 3 months, attached • to the intestinal wall of the mammalian hosts (humans and pigs). EGG MORPHOLOGY • Hen’s egg appearance. • Ellipsoid, Operculated, Nonembryonated. o Operculum at more pointed end. • Similar appearance to Fasciola • Eggs are often reported “Fasciola/Fasciolopsis” eggs due to morphologic overlap (CDC). ADULT MORPHOLOGY • • • • • • No cephalic cone. No shoulders. Testes o Very large. o Dendritic in tandem. Ovary o Branched, but usually obscured. Unbranched Intestinal Ceca. Ventral sucker is larger than oral sucker. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) PATHOLOGY • DIAGNOSIS • TREATMENT PREVENTION CONTROL AND • • • Intestinal Flukes: Fasciolopsis spp. Fasciolopsiasis o Ulceration (with/without hemorrhage) of bowel mucosa. o Abdominal pain for heavy infection. ▪ Stools are profuse, light yellow. • Malabsorption ▪ Impaired Vitamin B12 Absorption. Eggs in stool or vomitus o Adult recovered in stool after anthelminthic drug is given. o Correlate findings with patient history for definitive diagnosis. Drug of Choice: Praziquantel. Washing of the plants to remove metacercariae/Boiling of the plants to kill the parasites. o Soaking of aquatic plants in water should be avoided because metacercariae are very sensitive to dryness. o Time between harvest and consumption could also be prolonged to prevent infection. Swamps or ponds where aquatic plants are cultivated should be protected from pollution by untreated human or pig excreta. Liver Flukes: Fasciola • Fasciola hepatica “Temperate Liver Fluke.” • Fasciola gigantica “Tropical Liver Fluke.” • CAN ENCYST FREELY IN WATER. HABITAT Bile ducts connected with liver (hepatic bile ducts). DEFINITIVE HOSTS Humans FIRST INTERMEDIATE Snails HOST • Lymnaea philippinensis; • Lymnaea auricularia rubiginosa. SECOND Aquatic Plants INTERMEDIATE HOST • Ipomea obscura (Kangkong) • Nasturtium officinale (Water cress) RESERVOIR HOST Sheep, cow, etc. INFECTIVE STAGE 1ST INTERMEDIATE Miracidium. HOST 2ND INTERMEDIATE Gymnocephalus cercaria (big head cercaria). HOST DEFINITIVE HOST Metacercaria. GENERALIZED LIFE CYCLE 1 Immature eggs are discharged in the biliary (DIAGNOSTIC ducts and passed in the stool image. Eggs STAGE) become embryonated in freshwater over ~2 weeks. 2 Embryonated eggs release miracidia. 3 Miracidia invade a suitable snail intermediate host. 4 In the snail the parasites undergo several developmental stages (sporocysts to rediae to cercariae). 5 The cercariae are released from the snail and encyst as metacercariae on aquatic vegetation or other substrates. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) 6 (INFECTIVE STAGE) 7 (IN HUMANS) 8 • • • • • The human and other mammalian hosts become infected by ingesting metacercariae on the aquatic plants. After ingestion, the metacercariae encysted in the duodenum. After ingestion, the metacercariae excyst in the duodenum and penetrate through the intestinal wall into the peritoneal cavity. The immature flukes then migrate through the liver parenchyma into biliary ducts, where they mature into adult flukes and produce eggs. In humans, maturation from metacercariae into adult flukes usually takes about 3–4 months; development of F. gigantica may take somewhat longer than F. hepatica. Note: o In bile ducts connected with liver and not intestines. o Same life cycle pattern as Fasciolopsis, only difference is habitat. ADULT MORPHOLOGY Fasciola hepatica Fasciola gigantica Large broad and flat body. • Longer, Bay-Leaf appearance. Has a Cephalic Cone. • Short cephalic cone. o WIth Marked widening at base of cone o Less prominent shoulders. (Shoulder). • More dendritic ovaries. o Better to use for identification. o Longer branches. Dendritic Ovary. Highly Branched Testes in Tandem. PATHOLOGY • Liver Flukes: Fasciola Fascioliasis o Acute Stage ▪ Invasive phase. ▪ Coincides with larval migration as it burrows to liver. ▪ Sudden onset of high fever, hepatomegaly, and marked eosinophilia. ▪ Necrosis may occur when parasite burrows in the liver parenchyma. o Chronic Stage ▪ Asymptomatic. ▪ Parasite already reached bile ducts. ▪ Cholelithiasis may result. • Bile duct will become clogged/blocked. Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • • • • DIAGNOSIS • • • • TREATMENT PREVENTION CONTROL AND • • • Results in gray-white stool (from no bile). Atypical Manifestation of Fascioliasis o Hemorrhagic Nasopharyngitis and Dysphagia ▪ Adult parasite attaches to posterior pharynx. ▪ acquired by eating law liver (pork or beef). ▪ Also called as: • Halzoun in Lebanon. Marrara in Sudan. Diagnosis of infection, whether acute or chronic phase is difficult due to overlapping symptoms. Determining phase of infection will depend on clinical suspicion o A history of eating raw, improperly cooked freshwater vegetation or of living in or travel to an endemic area is suggestive of infection. Selection of adequate serological and coprological methods can help determine the phase of infection when applied to the acute or chronic stages, respectively. Parasitological diagnosis may be made through the identification of eggs in stool, duodenal contents, or bile, or the recovery of adult worms during surgical exploration, after treatment, or at autopsy. o However, eggs are present in very small numbers at irregular intervals (difficult to find). o Eggs may also be transiently present in the stool after ingestion of poorly cooked liver from infected animals (spurious or false fascioliasis). Immunologic methods are preferable to egg examination for the detection of acute infections. o Immunodiagnosis including enzyme-linked immunosorbent assay (ELISA) and Western blot are now widely applied as alternative methods of confirming early and extrabiliary human fascioliasis. Radiological examinations may also help in the diagnosis of fascioliasis. o Sonography and computed tomography (CT). Drug of Choice: Triclabendazole. Fasciola & Fascioliasis o Community Health Education ▪ Proper cultivation of vegetables • Water source and vegetation should not be accessible to reservoir hosts. • Dried Aquatic plants are safer (Desiccation kills metacercaria). ▪ Proper preparation of vegetables • Adequate Washing; • Boiling kills the metacercaria. FLUKES THAT LAY EMBRYONATED EGGS Clonorchis sinensis, Opistorchis spp., Dicrocoelium dendriticum, Heterophyes heterophyes, Metagonimus yokogawai, Eurytrema pancreaticum • Adult worms lay embryonated egg. • Egg is passed in stool and hatch inside the first snail intermediate host. o Except: Schistosoma. REPRESENTATIVE ORGANISMS Liver Flukes Clonorchis sinensis Opistorchis spp. Dicrocoelium dendriticum Intestinal Flukes Heterophyes heterophyes Metagonimus yokogawai Pancreatic Flukes Eurytrema pancreaticum Liver Flukes: Clonorchis sinensis GENERALIZED INFORMATION COMMON NAME HABITAT DEFINITIVE HOSTS Chinese Liver Fluke Biliary duct of definitive host. Humans Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) 1ST INTERMEDIATE HOST Snails • • • 2ND INTERMEDIATE HOST 1ST INTERMEDIATE HOST 2ND INTERMEDIATE HOST DEFINITIVE HOST 1 (DIAGNOSTIC STAGE) 2 3 4 5 6 (INFECTIVE STAGE) 7 8 EGG MORPHOLOGY Bithynia fuchsiana; Parafossarulus manchouricus; Simisulcospica libtertine. • Cyprinidae fish o Ctenopharyngodon idella (grass carp). INFECTIVE STAGE Embryonated egg. Pluerolophocercous cercaria • Has a fin on the dorso-ventral side. • Has eye spots. Metacercaria. LIFE CYCLE Clonorchis sinensis eggs are discharged in the biliary ducts and in the stool in an embryonated state. Eggs are ingested by a suitable snail intermediate host. Eggs release miracidia. Miracidia go through several developmental stages (sporocysts to rediae to cercariae). The cercariae are released from the snail and, after a short period of free-swimming time in water, they come in contact and penetrate the flesh of freshwater fish, where they encyst as metacercariae. Infection of humans occurs by ingestion of undercooked, salted, pickled, or smoked freshwater fish. After ingestion, the metacercariae excyst in the duodenum and ascend the biliary tract through the ampulla of Vater. Maturation takes approximately one month. The adult flukes (measuring 10 to 25 mm by 3 to 5 mm) reside in small and medium sized biliary ducts. • • • • • Old-fashioned light bulb appearance. Pitcher-shaped. Anterior is tapered. Convex operculum. Has prominent shoulder rim and an abopercular knob (comma-shaped). Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) • • ADULT MORPHOLOGY • • • COMMON NAME HABITAT DEFINITIVE HOSTS 1ST INTERMEDIATE HOST 2ND INTERMEDIATE HOST Spatula-shaped (tapered ends) Vitellaria is characteristically place at the middle third of the body. Testes: Large, highly branched (dendritic) in tandem. Intestinal Ceca: Long, simple, unbranched. Ventral sucker is small (obscured by uterus). Liver Flukes: Opisthorchis viverrinI Southeast Asian Fluke Biliary duct of definitive host. Humans Snails (Bithynia siamensis). Cyprinidae fish (Ctenopharyngodon idella [grass carp]). 1ST INTERMEDIATE HOST 2ND INTERMEDIATE HOST INFECTIVE STAGE Embryonated egg. Pleurolophocercous cercaria. DEFINITIVE HOST Metacercaria. 1 (DIAGNOSTIC STAGE) 2 3 4 5 6 7 (INFECTIVE STAGE) 8 9 LIFE CYCLE The adult flukes deposit fully developed eggs that are passed in the feces. There is ingestion by a suitable snail (first intermediate host). Eggs release miracidia. Miracidia go through several developmental stages (sporocysts to rediae to cercariae). In the snail the parasites undergo several developmental stages (sporocysts to rediae to cercariae). The cercariae are released from the snail and, after a short period of free-swimming time in water, they come in contact and penetrate the flesh of freshwater fish, where they encyst as metacercariae. The mammalian definitive host (cats, dogs, and various fish-eating mammals including humans) become infected by ingesting undercooked fish containing metacercariae. After ingestion, the metacercariae excyst in the duodenum and ascend the biliary tract through the ampulla of Vater. Attach and develop into adults, which lay eggs after 3 to 4 weeks. They reside in the biliary and Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) pancreatic ducts of the mammalian host, where they attach to the mucosa. EGG MORPHOLOGY • No prominent shoulder • Musk-melon ridge pattern on surface if stained with Potassium Permanganate or Methylene Blue. ADULT MORPHOLOGY COMMON NAME HABITAT DEFINITIVE HOST 1ST INTERMEDIATE HOST 2ND INTERMEDIATE HOST EGG MORPHOLOGY ADULT MORPHOLOGY PATHOLOGY DIAGNOSIS TREATMENT PREVENTION AND CONTROL • • • Slimmer than Clonorchis. Deeply lobulated testes in obliqued tandem. Dendritic uterus. Liver Flukes: Opisthorchis felineus Cat Liver Fluke/Siberian Liver Fluke (high incidence in Europe) Biliary duct of definitive host. Humans. Snails (Bithynia tentaculate) Cyprinidae fish (Leuciscus idus [ide/orfe]) Eggs are similar to O. viverrini. • Lobulated testes in obliqued tandem. • Lesser lobulations than O. viverrini. Liver Flukes: Clonorchis and Opisthorcis Acute Stage o Asymptomatic except for O. felineus o If heavy worm burden: Acute Pain in Right Upper Quadrant of Abdomen. • Chronic Stage o Liver Malfunction (Cholecystitis and Hepatitis) • Late complications o Hepatocellular Carcinoma o Cholangiocarcinoma Detection of the parasite egg in the stool. Drug of Choice: Praziquantel. • Community Health Education o Proper preparation and cooking of Fish ▪ Salting cannot kill the metacercaria. • Irradiation of Fish Host o Can kill metacercaria at a dose of 0.15 kGy of radiation. • COMMON NAME HABITAT DEFINITIVE HOSTS ACCIDENTAL HOST Liver Flukes: Dicrocoelium dendriticum (formerly known as Fasciola lanceolata) Lancet Fluke Biliary duct of definitive host. Ruminants (cattle and sheep). Humans Fortuno, Jaurigue, Lamano MIDTERMS | CLPARA (LEC) | MT3B Week 9 | Prof. Abarca | Trematodes (Part 1) 1ST INTERMEDIATE HOST Terrestrial Snails (Cochlicopa lubrica) 2ND INTERMEDIATE HOST Ants (Formica fusca) FIRST HOST SECOND HOST INTERMEDIATE Embryonated egg. INTERMEDIATE Xiphidiocercous cercaria. INFECTIVE STAGE DEFINITIVE HOST 1 (DIAGNOSTIC STAGE) 2 3 4 5 6 (INFECTIVE STAGE) 7 Note: • • Metacercaria. LIFE CYCLE Embryonated eggs containing miracidia are shed in feces of definitive hosts, which are typically ruminants. The eggs are then ingested by the first intermediat