Tissue & Body Fluid Nematode PDF

Tissue & Body fluid Nematode Prepared by: Dr. Shirley Tang Gee Hoon RECALLED: HELMINTHOLOGY Helminthology Helminths (worms): multicellular parasites Nemathelminths Platyhelminths...

Tissue & Body fluid Nematode Prepared by: Dr. Shirley Tang Gee Hoon RECALLED: HELMINTHOLOGY Helminthology Helminths (worms): multicellular parasites Nemathelminths Platyhelminths (Round worms) (Flat worms) They are divided into: Class Trematoda Class Nematoda (Flukes) Class Cestoda (Tape worms) RECALLED: HELMINTHOLOGY RECALLED: HELMINTHOLOGY FILARIASIS Is the infection by filarial worms Nematodes belonging to the superfamily Filarioidea, slender thread-like worms Classified according to the habitat of the adult worms in the body: 1. Lymphatic filariasis 2. Subcutaneous filariasis 3. Serous cavity filariasis CLASSIFICATION OF FILARIASIS BASED ON LOCATIONS IN BODY Lymphatic filariasis Subcutaneous Serious cavity filariasis filariasis Wucherichia Loa loa Mansonella bancrofti perstans Brugia malayi Onchocerca Monsonella volvulus azzardi (They are virtually non- pathogenic Brugia timori Mansonella streptocerca Lymphatic filariasis LYMPHATIC FILARIASIS Also known as Elephantiasis painful, disfiguring swelling of the legs and genital organs-is a classic sign of late-stage disease. A disease caused by the infection of filarial worm Disease transmitted by mosquito carrying the filarial worm infective larvae A major health problem in developing country LYMPHATIC FILARIASIS Prevalent in tropical and sub-tropical areas where mosquito vectors are abundant. However incidence is decreasing in Malaysia due to the effective control program. Filariasis in Malaysia is seen in rural areas or in the estates LYMPHATIC FILARIASIS 3 species of human filarial worms : 1. Brugia malayi (B. m) 2. Brugia timori (B. t) 3. Wuchereria bancrofti (W. b) In Malaysia only B. malayi & W. bancrofti are found. B. timori is found in Timor island, Indonesia LYMPHATIC FILARIASIS IN MALAYSIA 1st report: year 1986 but no details were available (Yap et al. 1968) The earliest report described microfilaria as sub-periodic B. malayi in 82 persons among 1613 people examined in seven villages in Serian District, Sarawak (Rubis et al. 1981). Endemic in 8 states; Kedah, Perak, Johor, Pahang, Terengganu, Kelantan, Sabah and Sarawak. Myhealth_Filariasis Malaysia Al-Abd et al. 2014 Lymphatic Filariasis in Peninsular M'sia LYMPHATIC FILARIASIS IN MALAYSIA GEOGRAPHICAL DISRIBUTION W. b – Asia & African continent India, China, Burma, Malaysia, Thai, Samoa, Bangladesh, Fiji, New Guinea, Pacific Islands, Africa B. m – Asia only - India ,Malaysia, Indonesia, China Vietnam, Kampuchea, Laos, Sri Lanka, Philipine, Indonesia, Philippines, Thailand, Vietnam, South Korea and Japan. HABITAT Adult worm lives in the lymphatic system and lymph nodes Microfilaria (pre larval stage) found circulating in the blood For W. b, adult worm lives in the lymphatic system of lower limb and body parts between the abdomen and thigh and also in the lymphatic system of the upper limb Wuchereria bancrofti Transmission of W.b Bite of mosquito carrying filariform larva Vector: mosquito Species depends on the geographic area Africa – Anopheles, Mansonia America – Culex Pacific and in Asia – Aedes in India and most other parts of Asia is Culex quinquefasciatus Morphology-Wuchereria bancrofti i) Adult worms whitish, thread-like worms with smooth cuticle and tapering ends the female (4-10cm) is larger than male (2-4cm) the life span of adult worm is 10 to 15 years. found in the lymphatic vessels and lymph nodes. Morphology-Wuchereria bancrofti Adults of W. bancrofti. The male worm is on the left; the female is on the right. Microfilaria (Mf) is more important to identify. Morphology - Wuchereria bancrofti ii) Embryos (Microfilariae, Mf) 250 to 300 µm length Infective form: Third-stage filariform larva, L3 colorless and transparent blunt heads and pointed tails. covered by a hyaline sheath, within which it can actively move forwards and backwards as sheath is much longer than the embryo Body nuclei: discrete and countable, no overlap. No terminal nuclei (distinguishing character from other Mf). Short cephalic (ratio is 1:1) Present in the peripheral blood of humans. Morphology - Wuchereria bancrofti ii) Embryos (Microfilariae) Do not multiply or further develop in human body If they are not taken up by a female vector mosquito, they die. Lifespan: about 2–3 months. Show nocturnal periodicity in peripheral circulation and are present in peripheral blood only at night (between 10 pm and 2 am). This coincides with the night-biting habit of the vector mosquito. Wuchereria bancrofti microfilaria Note that the pointed tail is free of nuclei  Life cycle for filarial worm 1. Definitive host: W.b: Man B.m: Man and Animal (eg: monkey, cat, dog) 1. Intermediate host: Female mosquito, of different species acts as vectors in different geographic areas.  Life cycle Wuchereria bancrofti Different species of mosquitoes are vectors of W. bancrofti filariasis depending on geographical distribution. The species including: i. Culex ii. Anopheles iii. Aedes iv. Mansonia 1. When vector mosquito takes a blood meal, the infective L3 larvae enter the human skin.  Life cycle Wuchereria bancrofti 2. They enter the circulation and develop into adults in the lymphatics. 3. The female adult worm produces sheathed microfilariae that migrate into lymph and blood channels. 4. When vector mosquito takes a blood meal, it ingests microfilariae.  Life cycle Wuchereria bancrofti 5. The microfilariae shed sheaths, penetrate the midgut of the mosquito, and migrate to the thoracic muscles. 6. It develops into L1 larva. 7. It moults twice and develops into L3 larva. 8. The L3 larvae migrate to the head and proboscis of the mosquito can infect another human when the mosquito takes a blood meal. Brugia malayi Transmission By the bites of mosquito carrying filarial larva. Brugia malayi Vector Strain periodic Anopheles campestris Anopheles donaldi Mansonia uniformis Mansonia dives Infect Man Strain Subperiodic Mansoni dives Mansonia B. malayi also uniformis Mansonia infects felines & annulata monkey Morphology - Brugia malayi The adult worms are similar to W. bancrofti, but smaller in size. Length; 53mm for female & 24mm for male Thick blood smears stained with Giemsa Brugia malayi microfilaria Microfilariae the tail has two distinct terminal nuclei (sub-terminal & terminal) released into the bloodstream Overlapping body nuclei kinky, cephalic space is longer (ratio is 2:1) Sheath is well stained Note the 2 distinct nuclei at the tip of the tail Brugia malayi microfilaria  Overlapping body nuclei Sub-terminal nucleus Terminal nucleus Brugia malayi Wuchereria bancrofti Life cycle Brugia malayi (Same as W.b) Brugia timori  Brugia timori Limited to Timor and some other islands of Eastern Indonesia. The vector of B. timori is Anopheles barbirostris, which breeds in rice fields and is a night feeder. Definitive host: Man. No animal reservoir is known. The Mf is larger than Mf malayi. The sheath of Mf timori fails to take Giemsa stain with 5-8 nuclei present in the tail. Lesions: milder than those of bancroftian or malayan filariasis. Microfilarial Periodicity  Periodicity It is defined as the time when most of the microfilariae are found in the peripheral blood. Microfilariae of various filarial worms exhibit different periodicity and are found in the peripheral blood in different time of the day such as: Periodicity due to the biting habits of the vectors (eg: Culex bites in night, Aedes bites in daytime) Other factors like sleeping pattern of the individual, temperature and other climatic conditions also contribute Note: When not in peripheral blood, the microfilariae are found in the pulmonary blood vessels. Differences between Wb and Bm W. bancrofti vs B. malayi Morphology W. bancrofti B. malayi Common name Bancroft’s Filarial Worm Malayan Filarial Worm Final host Anopheles, Aedes, Culex, Mansonia, Aedes Mansonia Host-adult worm Lower lymphatic Upper lymphatic Diagnostic stage Microfilaria Microfilaria Infective stage L3 filariform L3 filariform Mode of transmission Skin penetration through Skin penetration through vector vector Periodicity Nocturnal Nocturnal as well as subperiodic nocturnal Cephalic space Short (1:1) Long (2:1) Sheath affinity to Unstained Stained-pink Giemsa W. bancrofti vs B. malayi Morphology W. bancrofti B. Malayi Body nuclei Regularly shaped Overlapping/ crowded and irregular Terminal nuclei None Two nuclei Appearance Graceful curve Kinky/ stiff Pathology Bancroftian Filariasis Malayan Filariasis Length Larger Smaller W. bancrofti vs B. malayi Microfilariae of W. bancrofti in Microfilaria of B. malayi in thick blood smears a thin blood smear Pathogenesis & Clinical features of Filariasis Clinical incubation period: The period from the entry of the infective larvae, till the development of the earliest clinical manifestation This is very variable, but is usually 8-16 months, though it may often be much longer.  Pathogenesis Depends on the immune system and inflammatory responses of the host. Infection of W. bancrofti is named Wuchereriasis or bancroftian filariasis. B.malayi causes brugian/malayan filariasis ▪ similar to bancroftian filariasis but there is no chyluria and no involvement of male genitalia ▪ usually restricted to the legs. Note: Chyluria (also called chylous urine, is a medical condition involving the presence of chyle in the urine stream, which results in urine appearing milky white), chyle (a milky fluid containing fat droplets which drains from the lacteals of the small intestine into the lymphatic system during digestion).  Pathogenesis Though L3 larva are infective larva but they do not have any pathogenic effect. Can present as: i. Classical filariasis: Pathogenic states are produced only by adult worms (living/dead present in the lymphatic vessels) i. Occult filariasis: lesions are produced by hypersensitivity reaction to microfilarial antigens Pathogenesis: Classical filariasis The blockage could be due to The affected lymph nodes & Due to blockage of mechanical factors or lymph vessels and lymph vessels are infiltrated with allergic inflammatory macrophages, eosinophils, nodes by the adult worms reactions to worm antigens lymphocytes & plasma cells. and secretions. The worms inside lymph nodes The vessel walls get thickened Inflammatory changes & vessels may cause & the lumen narrowed or damage the valves in granuloma formation, with occluded, leading to lymph lymph vessels, further subsequent scarring & even stasis & dilatation of lymph aggravating lymph stasis. calcification. vessels. ↑ permeability of lymph vessel Fibroblasts invade the walls lead to leakage of protein- edematous tissues, laying down Recurrent secondary rich lymph into the tissues. This fibrous tissue, producing the bacterial infections produces the typical hard pitting nonpitting gross edema of cause further damage. or brawny edema of filariasis. elephantiasis. Clinical manifestations of Classical Filariasis Can be classified as: i. Asymptomatic (in endemic areas) ii. Acute/Inflammatory phase iii. Chronic/Obstructive phase Clinical manifestations of Classical Filariasis Asymptomatic phase (In endemic region) People in this stage have microfilariae in their blood In endemic regions, they do not show any clinical manifestation of filariasis. They may remain asymptomatic for years or even after life.  Clinical manifestations of Classical Filariasis Acute (inflammatory) stage: The Ags from the adult worms elicit inflammatory responses. Characterized by: ▪ Fever (usually low grade but occasionally severe), ccompanied by chills, general malaise, headache and pain ▪ Lymphadenitis (Inflammation of lymph nodes) ▪ Lymphangitis (Inflammation of lymph vessels) ▪ Lymphoedema Lymphangitis In some cases, the male genitalia is affected leading to funiculitis, epidydimitis or orchitis (redness, painful and tender scrotum) Clinical manifestations of Classical Filariasis Acute (inflammatory) stage: These acute symptoms subside after 5–7 days. Other symptoms that may occur include orchitis and epididymitis. Orchitis  Clinical manifestations of Classical Filariasis Chronic stage: Obstructive phase usually takes 10-15 years to develop. Caused by blockage of lymph vessel and lymph nodes by the adult worms Characterized by ▪ Hydrocoele (swelling of the scrotum and accumulation of fluid in the testes) Hydrocele by W.b ▪ Lymphedema (swelling of the upper and lower extremities)  Clinical manifestations of Classical Filariasis Chronic stage: Characterized by ▪ Elephantiasis (enlargement and thickening of the skin of the lower and/or upper extremities, scrotum, breast) ▪ Lymphangiovarix (dilatation of lymph vessels commonly occurs in the inguinal, scrotal, testicular and abdominal sites) ▪ Chyluria (lymph in urine due to rupture of lymph varices). Clinical manifestations of Classical Filariasis Hydrocoele: Elephantiasis Clear or straw-colored hydrocele fluid accumulate in the closed sac of testis Lymphedema Clinical manifestations of Classical Filariasis Elephantiasis Clinical manifestations of Classical Filariasis Scrotal elephantiasis by W.b Clinical manifestations of Classical Filariasis Chronic stage: Microfilariae are not normally present in the chronic phase. Elephantiasis affects men mainly in the legs, arms and scrotum. In women, the legs, arms and breasts are affected. Bm – below knee elephantiasis, hydrocoele is rare Wb – above knee elephantiasis, upper limb, male genitalia Incubation period is about 8–12 months. Pathogenesis of Occult Filariasis Occult Filariasis: Also known as Meyers Kouwenaar syndrome Occurs as a result of hypersensitivity reaction to microfilarial antigens, not directly due to lymphatic involvement. Microfilariae are not found in blood, as they are destroyed by the allergic inflammation in the tissues. Clinical Manifestations of Occult Filariasis Massive eosinophilia (30-80%) Hepatosplenomegaly Pulmonary symptoms like dry nocturnal cough, dyspnea and asthmatic wheezing. Occult filariasis has also been reported to cause arthritis, glomerulonephritis, thrombophlebitis, tenosynovitis, etc. Classical features of lymphatic filariasis are absent.  Clinical Manifestations of Occult Filariasis Tropical pulmonary eosinophilia: ▪ with low-grade fever, loss of weight, and pulmonary symptoms such as dry nocturnal cough, dyspnea and asthmatic wheezing. ▪ a marked increase in eosinophil count (>3000 μm which may go up to 50,000 or more). ▪ Chest X-ray shows mottled shadows similar to miliary tuberculosis. ▪ Elevated serum IgE (>1000 IU/mL) and filarial antibodies. ▪ Serological tests with filarial antigens are strongly +ve. ▪ Clinical response to diethylcarbamazine (DEC) Classical Vs Occult Filariasis Laboratory Diagnosis Laboratory Diagnosis 1. Microscopic examination of blood smear Detection of Mf in thick blood film, chylous urine and hydrocele fluid stained with Giemsa or H&E. Blood collection should be done at night between 10 pm to 2 am. Microfilariae circulate in the blood at night (nocturnal periodicity), Daytime – microfilaria stay in the pulmonary vessels DEC provocation test is useful to bring out the mf into peripheral circulation for blood collection during day time Detection of adult worms in lymph node biopsies. Chylous: milky fluid consisting lymph and emulsified fats Laboratory Diagnosis 1. Microscopic examination of blood smear Concentration techniques can be used to increase sensitivity Centrifugation of the blood sample lyzed in 2% formalin Filtration through a Nucleopore® membrane Detection of adult worms in lymph node biopsies.  Laboratory Diagnosis 2. Serological test ELISA can be used for detection of antibodies to larval antigens Immunochromatographic test (ICT). Blood samples can be collected at any time of the day. Laboratory Diagnosis 3. Molecular diagnosis using PCR Lymphedema (swelling) usually developed many years after infection, lab tests are most likely to be negative Detect filarial deoxyribonucleic acid (DNA) from patient's blood, only when circulating microfilaria are present in peripheral blood Laboratory Diagnosis Chylous urine- milky appearance  Treatment Diethylcarbamazine (DEC) 6mg/kg and Albendazole 400mg in combination given simultaneously under Direct Observation Therapy (DOT) Surgical required for hydrocele, but rarely successful In elephantiasis: elevation of the affected limb & use of elastic bandage & foot care to reduce symptoms Special boots (Unna’s paste boots) or elastic bandages → reducing the size of enlarged limb. Medical management of chyluria includes bed rest, high protein diet and treatment with DEC. Treatment  Prevention & Control In Malaysia - National Lymphatic Filariasis Elimination Program under Ministry of Health Malaysia with collaboration from World Health Organization. Through this program, a mass drug administration is carried out involving population in endemic area once a year for five cycles The objectives are : 1. To stop the transmission of filariasis infestation and 2. To control the morbidity lymphatic filariasis patient  Prevention & Control This program also involves health education to the community to increase their knowledge regarding the disease. emphasis on healthy life style and personal hygiene especially among the affected patients.  Prevention & Control Bld screening in endemic areas and probe study to identify new endemic areas. Treatment with DEC & Albendazole for pts, mass or selective chemotherapy in endemic areas Vector control through spraying and treated nets for periodic type of infection, larvae eating fish may be added to the ponds. Environmental surveillance to study ecology, entomology and vector density of endemic areas Avoidance of contact with the vectors eg. Proper clothing, use of repellant Subcutaneous filariasis  Loa-loa Loa loa is also known as African eyeworm Causes loiasis (fugitive swelling) Vectors: Day-biting flies (Chrysops). Microfilaria is sheathed and nuclei extend up to the tail tip. Microfilaria appears during the day (diurnal periodic).  Loa-loa: Clinical features The pathogenesis of loiasis depends on the migratory habit of the adult worm. Clinical features: Subcutaneous swellings (Calabar/ fugitive swellings) (adult worms wanderings through subcutaneous tissues set up temporary foci of inflammation) Ocular manifestations: ocular granuloma, edema of eyelid and proptosis. Loa-loa: Diagnosis and Treatments Treatment: Diethylcarbamazine with simultaneous administration of corticosteroid of other drugs which may be used. lvermectin or albendazole.  Onchocerca volvulus Onchocerca volvulus, produces onchocerciasis or "river blindness". The adult worm is white with transverse striation on the cuticle. The posterior end is curved. Microfilaria is unsheathed, tail-tip free of nuclei and nonperiodic. Definitive host: Humans. Intermediate host: Female black flies (Simulium).  Onchocerca volvulus Clinical features: Subcutaneous nodule formation Onchocercoma (onchocercoma). ▪ Subcutaneous nodules are firm, non-tender, O. volvulus from a skin nodule stained variable in size containing the coiled adult with hematoxylin worms and eosin stain (H & E) Ocular manifestations- Conjunctivitis with (A) microfilariae photophobia (most common early findings), sclerosing keratitis, secondary glaucoma, optic atrophy, chorioretinitis (2nd major cause of blindness in world) Bilateral blindness (River blindness) O. volvulus: Diagnosis and Treatments Treatment: lvermectin is the drug of choice except in areas coendemic for O. volvulus and L. loa.  Mansonella streptocerca seen only in West Africa. The adult worms live in the dermis, just under the skin surface. The unsheathed microfilariae are found in the skin. Vectors: Culicoides species Reservoir hosts: Chimpanzees Infection: dermatitis with pruritus and hypopigmented macules. Diagnosis: microfilariae in skin clippings Treatment: Ivermectin Serous Cavity Filariasis  Mansonella ozzardi New World filaria is seen only in Central and South America and the West Indies. The adult worms are found in the peritoneal and pleural cavities of humans. Nonperiodic unsheathed microfilariae are found in the blood. Culicoides species are the vectors. Infection does not cause any illness. Diagnosis: demonstrating microfilariae in blood. Treatment: lvermectin  Mansonella perstans Extensively distributed in tropical Africa and coastal South America The adult worms live in the body cavities of humans, mainly in peritoneum, less often in pleura, and rarely in pericardium. The microfilariae are unsheathed and subperiodic. Vectors: Culicoides species African primates: reservoir hosts Infection is generally asymptomatic, though it has been claimed that it causes transient abdominal pain, rashes, angioedema and malaise. Diagnosis: microfilariae in peripheral blood or serosal effusion. Treatment: Doxycycline Questions Discuss lymphatic filariasis based on the following topics – List the species – Describe the life cycle Discuss lymphatic filariasis endemic in Malaysia based on the following topics – The types and vectors – Periodicity – Pathogenesis and clinical manifestations Discuss lymphatic filariasis based on the following topics – The diagnosis – Control and prevention