W. bancrofti. MLT GROUP Presentation.pptx

W. bancrofti.

1. GROUP D FRANK AWUKU OBED AKWASI ANING KENNETH KWESI DESBORDES LATIF ADAMS

2. WUCHERERIA BANCROFTI

3. Wuchereria bancrofti ( Filaria ) A parasitic filarial nematode spread by a mosquito vector. It is one of the three parasites that cause lymphatic filariasis , an infection of the lymphatic system by filarial worms. The females produce juvenile larva called microfilaria which live in the deep blood vessels.

4. Wuchereria bancrofti ( Filaria ) Its interactions are with humans( definitive host ) and mosquito( intermediate host ). The adult lives in the lymphatic glands of humans and usually thrives in the ducts and emanating from major lymph glands in the lower half of human the body.

5. EPIDEMIOLOGY It is primarily found in Africa, South America and other tropical and sub tropical countries . It affects approximately 80 countries and 120 million people have been documented as host of this nematode . 40 million of those infected are disfigured or severely incapacitated.

6. Red : Endemic Pink : Unknown Green : Unaffected GLOBAL DISTRIBUTION OF W. BANCROFTI INFECTIONS

7. MORPHOLOGY Adult Wuchereria bancrofti worms are slender and long, with bluntly rounded ends and smooth cuticles. Their head is slightly enlarged and bears two circles of distinct papillae. Their mouth is little, and the buccal capsule is absent. The females are slightly longer and wider than the males with a height and width of 6-10cm and 300 micrometers respectively . The males are 4cm long and 100 micrometers wide.

8. Morphology … con’t The vulva of the female is located near the level of the middle of their oesophagus It has a short cephalic region, dispersed nuclei throughout its body cavity with no nucleus at the tail tip.

9. The adult lives in the lymphatic Microfilaria of Wuchereria bancrofti , from a patient in Haiti (thick blood smear; hematoxylin stain). The microfilaria is sheathed, its body is gently curved, and the tail is tapered to a point. The nuclear column ( ie , the cells that constitute the body of the microfilaria) is loosely packed, the cells can be visualized individually and do not extend to the tip of the tail. The sheath is slightly stained by hematoxylin .

10. LIFE CYCLE

11. PATHOGENESIS The infective larva from the feeding vector mosquito migrate to the regional lymphatic vessels and by inducing the host inflammatory reaction causes the eventual blockage and edema characteristic of W. bancrofti infections. Pathology varies greatly from one individual to another. Host reaction to the parasite is considerable and worsens when; the worms molt. the females begin to produce microfilaria the worms die and degenerate

12. CLINICAL MANIFESTATION 1. Asymptomatic stage There is internal damage to the lymphatics and kidneys 2. Acute stage – Filarial lymphangitis Characterised by bouts of fever heat, redness, pain, swelling and tenderness of the lymph nodes and ducts

13. 3. Chronic stage Usually results in elephantiasis as a result of chronic lymphoedema There is a massive overgrowth of tissue resulting in severe deformities The legs are often affected and result in inability to walk The scrotum is often affected in men and the breasts and vulva in women CLINICAL MANIFESTATION

14. Elderly male with massive hydrocoele , and elephantiasis of the leg. A man suffering from elephantiasis

15. LABORATORY DIAGNOSIS Identification of microfilaria is best done by microscopic examination - Thick film stained with Giemsa or H & E. - Concentration technique - for increased sensitivity Antigen Detection – Immunochromatographic test Molecular Diagnosis -PCR

16. Wuchereria bancrofti in a thick film

17. TREATMENT Usually done using a drug called diethylcarbamazine (DEC). The medicine kills the microfilariae in the bloodstream and sometimes adult worms in the lymph vessels. DEC should only be used, if Wuchereria bancrofti has been identified. Ivermectin , can also be used, although it only kills microfilariae .

18. PREVENTION & CONTROL The skin must be kept clean by washing it with soap and water daily. Protection against mosquito bites especially in endemic regions. Public education in endemic areas to reduce the prevalence of Wuchereria bancrofti infections In some cases lymphedema can be prevented from getting worse by exercising the swollen leg or arm to improve the lymph flow.

19. REFERENCES District Laboratory Practice for Tropical Countries, M. Cheeseborough , Parasites and human disease, W. Crewe and D.R.W. Haddock, 1985, First edition, Edward Arnold. University of South Carolina School of Medicine: http://pathmicro.med.sc.edu/book/parasit-sta.htm