Filariae species & Lymphatic filariasis.pptx

Filariae are parasitic worms belonging to the family Filariidae and are responsible for a group of diseases known as filariasis. These thread-like nematodes typically inhabit the lymphatic system, subcutaneous tissues, or body cavities of their hosts, which include humans and other animals.

1. Filariae Blood and Tissue Nematodes Prof. Dr/ Ibrahim Aboul Asaad Lecture for PG Subsidiary Parasitology

2. Filariae are parasitic worms belonging to the family Filariidae and are responsible for a group of diseases known as filariasis. These thread-like nematodes typically inhabit the lymphatic system, subcutaneous tissues, or body cavities of their hosts, which include humans and other animals. The main species affecting humans are classified according to the habitat into: Introduction Lymphatic Group: * Wuchereria bancrofti , endemic in Africa & Egypt * Brugia malayi , endemic in Fare east 2) Cutaneous Group: * Onchocerca volvulus , , endemic in Africa * Loa loa , endemic in Africa Serous Group: * Mansonella ozzardi , endemic in Central and South America  * Mansonella perstans , endemic in Africa Filariasis is a significant public health problem in tropical and subtropical regions, affecting millions of people worldwide. Efforts by global health organizations aim to eliminate filariasis through widespread treatment and preventive measures. Filariae

3. 1) Adults : Pathogenic Stage 2) Microfilaria ( pre-larvae or embryos ): Diagnostic Stage 3) Larval stages: 5 larval stages Slender, creamy white & range from 2 to 50 cm in length. The male has curved posterior end with two copulatory spicules. The female: The female is viviparous and gives birth to microfilariae. Has two sets of genitalia; The vulva opens close to the anterior end. The adults: Morphology of Filariae The parasite stages Filariae

4. Microfilariae are the diagnostic stages ,,,,, why?? Microfilariae are released in blood, so can be detected in blood samples Each species of microfilaria has characteristic morphology and periodicity, Microfilariae: Microfilariae are "pre-larvae or advanced embryos" which will develop into (L1) in the arthropod vector. Larval stages: L1  L2  L3  L4  L5 Infective Stage Rhabditiform L In arthropde I.H Immature adult In D.H Filariae

5. Species Habitat D. H. I.H. (Vector) W. bancrofti Lymphatics Human only Culex , Aedes & Anopheles. B. malayi Lymphatics Human & R.H (monkey, cats) Anopheles, Mansonia L. loa Skin  Human only Chrysops (Deerfly) O. volvulus Skin  Human only Simulium (black fly) M. perstans Body cavities Human only Culicoides spp. M. ozzardi Body cavities Human only Culicoides spp. Life cycle Filariae Habitats and Hosts: Infective stage: Filariform larva (L3) Route of infection : Skin penetration through the insect bite Diagnostic Stage: Microfilariae Filariae

6. Transmission and Life Cycle: Filariae are transmitted to humans through the bites of infected mosquitoes (for lymphatic filariasis) or blackflies (for onchocerciasis). The life cycle of filariae involves several stages: Infection Stage : Larvae (L3) enter the host's body through insect bites. Migration and Maturation : The larvae migrate to specific tissues (lymphatic system, subcutaneous tissues or serous cavities) where they mature into adult worms. Reproduction : Adult worms reproduce, releasing new microfilariae into the host's bloodstream or skin, which can be ingested by biting insects, continuing the cycle. Filariae

7. Lymphatic Filariasis Wuchereria bancrofti Brugia malayi Brugia timori

8. Habitat: 2) Hosts: 4) Diagnostic stage: 5) Route of infection: 3) Infective stage: 6) Life span : Adult: Lymphatics Microfilariae: Blood (night) I.H. (Vector) Culex , Aedes Anopheles: W. bancrofti Anopheles, Mansonia : B. malayi D.H.: Human R.H.: monkey, cats for : B. malayi Filariform larva (L3) Skin penetration through the insect bite The microfilariae in blood Adult: 5 – 10 years & microfilaria: 5-20 months Life Cycle of lymphatic Filariae

9. Adults in lymphatics Microfilariae metamorphose to L1  2 molts  L3 MF penetrate stomach to thoracic muscle Infective (L3) enter through mosquito bite MF appear in peripheral blood at night Mosquito ingests MF with blood L3 molt twice & adults appear in lymphatics after 6-12 Ms L3 migrate to proboscis & drop on skin during biting Mosquito I.H. Mosquito I.H. Human D.H. Life Cycle of lymphatic Filariae

10. Lymphatic Filariasis: ELEPHANTIASIS Clinical aspects . Diagnosis. Treatment. Prevention & control of infection.

11. Clinical Aspects Filarial pathogenesis is caused mainly by adult worms Microfilariae do not cause pathological manifestations although they have been associated with granulomatous inflammation of the lung, liver, and spleen The infection could be classified into: Asymptomatic: Microfilaraemia without manifestations referable to their infection. Acute inflammatory filariasis . Chronic obstructive filariasis . Occult filariasis.

12. Acute Inflammatory Filariasis Caused by immunologic reaction to the toxic products of the adult worms. The manifestations occur in irregular attacks for months or years, and include : Lymphatic inflammations & Lymphatic oedema Lymphangitis accompanied by fever ( Filarial fever). Lymphadenitis: Inguinal, axillary, or cervical glands are enlarged & tender. Lymphatic Oedema of the affected limb is pitting and reversible with limb elevation indicating that there no lymphatic obstruction. Causes of Lymphangitis and Lymphangitis Mechanical irritation Liberation of metabolites of growing larvae & secretion of some toxic fluid by fertilized females Absorption of toxic products liberated from dead worms undergoing disintegration. Secondary bacterial infection

13. Lymphatic inflammations & Lymphatic oedema

14. 2) Epididymo-Orchitis Acute inflammation of the testis and epididymis  pain, scrotal swelling and redness, fever Recurrent attacks of orchitis  Collection of serous fluid in the cavity of the tunica vaginalis ( Hydrocoele ) 3) Filarial abscess Develops within superficial lymphatics on the limbs or scrotum. Rupture with ulcer formation and discharge of pus. Pus may be sterile or septic.

15. Chronic Obstructive Filariasis Elephantiasis It develops slowly after years of filarial infection. It is preceded by repeated acute inflammatory attacks & chronic oedema Pathogeneses of Lymphatic obstruction: Fibrosis following the repeated acute inflammatory attacks. The coiled worms or the proliferative granulation tissue after its death. Lymphatic obstruction leads to: Chronic lymphatic oedema Chyluria & Chylocele Elephantiasis Chronic lymphatic oedema Frequently affects the legs and external genitalia or the arms and breasts Non-pitting and irreversible with limb elevation.

16. 2. Chyluria & Chylocele Lymphatic obstruction  lymph varices  Rupture in the cavity of the Tunica vaginalis  Chylocele . Or rupture in the urinary bladder  Lymph passes with urine  Milky urine ( Chyluria ) 3. Elephantiasis Pathogenesis : Chronic lymphatic oedema leads to: Proliferation of the dermal and connective tissue of the skin due to the high protein content of the lymph. Gradually, over a period of years, the affected limb becomes thickened, rough and fissured.

17. Elephantiasis Lower limb Upper limb Scrotum Breast

18. 4. Occult Filariasis Filarial infections in which microfilariae are not found in the peripheral blood although they may be seen in tissues. Cause: Hypersensitivity reaction to filarial antigens derived from the microfilariae Clinical manifestations Tropical pulmonary eosinophilia (TPE) Severe Cough and wheezing. Peripheral blood eosinophilia . Extreme elevation of anti-filarial antibodies (especially IgE). Glomerulonephritis. Myocardial fibrosis. Filarial arthritis. Filarial fever. Diagnosis of Occult Filariasis: Peripheral blood eosinophilia. Extreme elevation of immunoglobins (especially IgE ). Extreme elevation of anti-filarial antibodies. Finding a circulating filarial antigen in the blood.

19. Clinical diagnosis: The presence of the characteristic signs and symptoms in persons in endemic regions. Laboratory diagnosis Direct laboratory diagnosis Indirect (Serological) diagnosis PCR Imaging techniques. Diagnosis of lymphatic Filariasis

20. 2) Laboratory diagnosis a) Direct laboratory diagnosis demonstration of adults in lymph node biopsy demonstration of microfilariae in: Blood sample Urine sediment, when chyluria present Lymph node aspirate or biopsy Blood sample: The proper blood samples can be obtained at night or after provocation test. DEC provocation test: Oral administration of 100 mg of (DEC) usually provokes movement of the microfilariae to the peripheral blood, within 30 - 45 minutes in daytime Examination of blood samples can be performed by: Thin or thick blood films stained with Wright’s or Giemsa stain. concentration method: Knott's concentration method. Membrane filtration concentration method.

21. W. bancrofti B. malayi Length 260 µm Length 220 µm Tail free of nuclei Tail contains nuclei Nocturnal Periodicit y Loose Sheath Microfilariae Sheath Sheath Microfilariae in blood film

22. Adult sections in lymph node biopsy

23. Microfilaria in Urine Sediment

24. Microfilariae cannot be detected in blood of the infected patient (False Negative ) in cases of: During the early months of infection. Chronic stages of elephantiasis  the adult worms and microfilariae may have died. In occult filariasis. In these situations, serological tests for detection of circulating filarial antigens or antibodies appear to be the diagnostic method of choice. b) Indirect (serological) diagnosis A polymerase chain reaction (PCR) assay based on detection of DNA sequence found in Filariae is useful in amicrofilaraemic cases. It is significantly more sensitive than current methods for diagnosing filariasis, and it overcomes many difficulties in identifying active infection. c) Polymerase Chain Reaction (PCR)

25. 3) Imaging techniques X-ray can show calcified died adult worm in lymphatics US, CT, or MRI may reveal living adult worms Ultrasound Filarial dance sign The constant movements of the worms in Chylus fluid during ultrasonography.

26. Medio -lateral oblique (MLO) view of a digital mammogram of the left female breast showing multiple coiled and serpiginous calcifications which are characteristic of calcified filarial worms within the breast parenchyma X-ray

27. Treatment General measures : Rest, antibiotics, antihistaminic and bandaging ii. Ant-filarial drugs: DEC or hetrazan : Oral dose of 2mg/kg tds for 12 days. It is very effective in killing the microfilariae. It is less effective in killing the adult worms Ivermectin It is effective in killing microfilariae, but not the adult. It has the advantage of being given in a single oral dose (200 µg/kg). Albendazole A course of 400mg twice daily for 3-week. Effective in killing the adults

28. iii. Surgical procedure: Plastic surgery for more advanced elephantiasis. Combined Therapy Albendazole combined with Ivermectin or (DEC) in a single dose is also effective treatment for killing adult filarial worms Doxycycline antibiotic Filarial parasites have symbiotic bacteria , which live inside the worm. When these bacteria are killed, the worms themselves also die. This can be obtained by 8-week treatment with doxycycline

29. Prevention and control Prevention and control strategies include vector control measures like insecticide-treated nets, indoor residual spraying, and larviciding , as well as personal protective measures such as repellents and protective clothing. Mass drug administration (MDA) of antiparasitic medications is crucial for reducing microfilariae levels and halting transmission. Additionally, morbidity management and disability prevention (MMDP) focus on lymphedema management and hydrocele surgery. Global efforts, led by the World Health Organization (WHO) and supported by various partnerships, aim to eliminate LF through coordinated interventions, community engagement, and ongoing surveillance.

30. Thank You Prof. Dr/ Ibrahim Aboul Asaad