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  1. 1. Lymphatic Filariasis / Elephantiasis Wuchereria bancrofti & Brugia malayi
  2. 2. What is it? <ul><li>Wuchereria bancrofti and Brugia malayi are filarial nematodes </li></ul><ul><li>Spread by several species of night - feeding mosquitoes </li></ul><ul><li>Causes lymphatic filariasis, also known as Elephantiasis </li></ul><ul><ul><li>Commonly and incorrectly referred to as “Elephantitis” </li></ul></ul>
  3. 3. + + = ?
  4. 4. Definitive Host <ul><li>Humans are the definitive host for the worms that cause lymphatic filariasis </li></ul><ul><li>There are no known reservoirs for W.bancrofti . </li></ul><ul><li>B.malayi has been found in macaques, leaf monkeys, cats and civet cats </li></ul>
  5. 5. Elephantiasis <ul><li>A Debilitating disease. </li></ul><ul><li>Abnormal accumulation of watery fluid in the tissues causing severe swelling. </li></ul><ul><li>Skin usually develops a thickened, pebbly appearance and may become ulcerated and darkened </li></ul>
  6. 6. Intermediate Host <ul><li>W.bancrofti is transmitted by Culex, Aedes, and Anopheles species </li></ul><ul><li>B.malayi is transmitted by Anopheles and Mansonia species. </li></ul>Anopheles Aedes Culex Mansonia
  7. 7. Geographic Range <ul><li>Lymphatic filariasis occurs in the tropics of India, Africa, Southern Asia, the Pacific, and Central and South America. </li></ul>
  8. 8. Terms to Know <ul><li>Elephantiasis : is a disease that is characterized by the thickening of the skin and underlying tissues, especially in the legs and genitals. </li></ul><ul><li>Filariasis : is a parasitic disease caused by roundworms </li></ul><ul><li>Lymph Edema : Is a condition of localized fluid retention caused by a compromised lymphatic system. </li></ul>
  9. 9. <ul><li>Brugia malayi : a causative agent of human lymphatic filariasis leading to lymph edema and swelling of the legs </li></ul><ul><li>Genome : a complete DNA sequence of one set of chromosomes. </li></ul>
  10. 10. Lymphatic Filariasis by the numbers <ul><li>Endemic in 83 countries </li></ul><ul><li>1.2 billion at risk </li></ul><ul><li>More than 120 million people infected </li></ul><ul><li>More than 25 million men suffer from genital symptoms </li></ul><ul><li>More than 15 million people suffer from lymphoedema or elephantiasis of the leg </li></ul>
  11. 11. Morphology - W.bancrofti <ul><li>W.bancrofti is a sexually dimorphic species. </li></ul><ul><li>The adult male worm is long and slender, between four and five centimeters in length, a tenth of a centimeter in diameter, and has a curved tail. </li></ul><ul><li>The female is six to ten centimeters long, and three times larger in diameter than the male. </li></ul><ul><li>Microfilariae are sheathed, and approximately 245 to 300 µm in length. </li></ul>
  12. 12. Morphology - B.malayi <ul><li>B.malayi microfilariae are slightly smaller than those of W.bancrofti. </li></ul><ul><li>Microfilariae are sheathed, and about 200 to 275 µm. </li></ul><ul><li>Not much is known about the adult worms, as they are not often recovered </li></ul><ul><li>One distinctive feature of B.malayi is that the microfilarial nuclei extends to the tip of the tail </li></ul>
  13. 13. Wuchereria Life Cycle
  14. 15. Symptoms <ul><li>1. Asymptomatic: patients have hidden damage to the lymphatic system and kidneys. </li></ul><ul><li>2. Acute: attacks of ‘filarial fever’ (pain and inflammation of lymph nodes and ducts, often accompanied by fever, nausea and vomiting) increase with severity of chronic disease. </li></ul><ul><li>3. Chronic: may cause elephantiasis and hydrocoele (swelling of the scrotum) in males or enlarged breasts in females. </li></ul>
  15. 16. Diagnosis <ul><li>The standard method for diagnosing active infection is the identification of microfilariae by microscopic examination </li></ul><ul><li>However, microfilariae circulate nocturnally, making blood collection an issue </li></ul><ul><li>A “card test” for parasite antigens requring only a small amount of blood has been developed </li></ul><ul><ul><li>Does not require laboratory equipment </li></ul></ul><ul><ul><li>Blood drawn by finger stick </li></ul></ul>
  16. 17. <ul><li>The table below shows how the symptoms are graded by severity of the swelling – known as a lymphœdema. These swellings usually occur in the legs, breast tissue and groin.  </li></ul>
  17. 18. Control <ul><li>As with malaria, the most effective method of controlling the spread of W.bancrofti and B.malayi is to avoid mosquito bites </li></ul><ul><li>The CDC recommends that anyone in at-risk areas: </li></ul><ul><ul><ul><li>Sleep under a bed net </li></ul></ul></ul><ul><ul><ul><li>Wear long sleeves and trousers </li></ul></ul></ul><ul><ul><ul><li>Wear insect repellent on exposed skin, especially at night </li></ul></ul></ul>
  18. 19. Vector control <ul><li>Covering water-storage containers and improving waste-water and solid-waste treatment systems can help by reducing the amount of standing water in which mosquitoes can lay eggs. </li></ul><ul><li>Killing eggs (oviciding) and killing or disrupting larva (larviciding) in bodies of stagnant water can further reduce mosquito populations. </li></ul>
  19. 20. Treatment <ul><li>Treatment of filariasis involves two components: </li></ul><ul><li>Getting rid of the microfilariae in people's blood </li></ul><ul><li>Maintaining careful hygiene in infected persons to reduce the incidence and severity of secondary (e.g., bacterial) infections. </li></ul>
  20. 21. Drugs, Drugs, Drugs! <ul><li>Anti-filariasis medicines commonly used include: </li></ul><ul><li>Diethylcarbamazine (DEC) </li></ul><ul><ul><li>reduces microfilariae concentrations </li></ul></ul><ul><ul><li>kills adult worms </li></ul></ul><ul><li>Albendazole </li></ul><ul><ul><li>kills adult worms </li></ul></ul><ul><li>Ivermectin </li></ul><ul><ul><li>kills the microfilariae produced by adult worms </li></ul></ul>
  21. 22. …And more drugs! <ul><li>The disease is usually treated with single-dose regimens of a combination of two drugs, one targeting microfilariae and one targeting adult worms (i.e.,either diethylcarbamazine and albenadazole, or ivermectin and albendazole </li></ul><ul><li>In some areas, DEC laced table salt is used as a prophylactic </li></ul>
  22. 23. Treatment 2: Manchester United 0 <ul><li>If a high enough coverage of anti-filariasis drug treatment can be achieved (treating greater than 80% of the people in a community), the disease can be eradicated from an area. </li></ul><ul><li>Attempts to eliminate the disease are being helped considerably by Merck and Co., which is donating ivermectin to treatment efforts, and Smith Kline Beecham, which is donating albendazole. </li></ul><ul><li>The Gates Foundation has also donated millions towards eliminating lymphatic filariasis </li></ul>
  23. 24. Elimination programs
  24. 25. Finally… <ul><li>http://youtube.com/watch?v=SkIryQ6Paqg </li></ul>