Hookworm

a detailed explanation of hookworm infection

1. HOOKWORM -LADI ANUDEEP ISM-IUK

2. ETIOLOGY Hookworms are intestinal ,blood feeding, parasitic roundworms that cause infections known as Helminthiases In humans hook worm infection caused by two main species of round worm belonging to Ancylostoma duodenale and Necator americanus In other animals the main parasites are species of ancylostoma brazilience and ancylostoma tubaeforme Wild cats are infected by ancylostoma pluridentatum Dogs are commlonly infected by ancylostoma caninum

3. EPIDEMIOLOGY Three conditions are important for transmission: Human fecal contamination of soil Favorable soil conditions for larva survival( moisture, warmth, shade) Contact of human skin with contaminated soil

4. Hookworm egg  The eggs are oval or elliptical, measuring 60 by 40 µm, colorless, not  bile  stained and with a thin transparent  hyaline  shell membrane.

5. LIFECYCLE The host is infected by larva not by eggs and usual route is skin Hookworm need moist soil, above 18c ,in order to hatch, they die if exposed to direct sunlight or if they become dry First stage larva [L1]are noninfective ,feed on soil microorganism until they moult into second stage larva[L2] First and second stage larva are in rhabditiform stage After feeding for seven days they moult into Third stage larva[L3]known as filariform stage .This is nonfeeding ,infective stage`

6. Common route of passage of larva is skin of bare foot walkers Once larva entered the host they travel in circulatory system to lungs , where they leave venules and enter alveoli Then they travel up trachea where they are coughed up, swallowed and end up in small intestine In small intestine, larva moult into stage 4 adult worm It takes from 5-9 weeks from penetration to maturity in intestine Worms need 5-7 weeks to reach maturity and symptoms of infection

7. CLINICAL FEATURES They lead to combination of intestinal inflammation and progressive iron deficiency anemia and protein deficiency Pulmonary manifestations : Cough, chest pain, pharyngeal irriation , wheezing, fever result from severe infection GIT manifestations : Epigastric pain, indigestion, nausea, vomiting, constipation, diarrhea, flatulence can occur in later stages Signs if advanced severe infection are protein deficiency anemia, cardiac failure, abdominal distension with ascites

8. DIAGNOSIS Microscopic examination of stools with standard technique called KATO KATZ technique Classification can be performed based on buccal cavity, space between oral opening and esophagus: Hookworm rhabditiform larvae have long buccal cavities Whereas strongyloides rhabditiform larvae have short buccal cavities Blood analysis shows eosinophilia(1350-3828 cells/microL) Recent research has focused on development of DNA based tools for diagnosis of infection   PCR  assays could serve as a molecular approach for accurate diagnosis of hookworm in the feces

9. TREATMENT Anthelminthic drugs: benzimidazoles( albendazole 400mg once on empty stomach, mebendazole 100mg 2 times for 3 days) In some cases, levamisole and pyrantel pamoate(11mg/kg/day for 3 days) may be used Efficacy of single dose treatment for hookworm infections is 72% for albendazole, 15% for mebendazole, 31% for pyrantel pamoate World Health Organization does recommend anthelmintic treatment in pregnant women after the first trimester.  It is also recommended that if the patient also suffers from anemia that  ferrous sulfate  (200 mg) be administered three times daily at the same time as anthelmintic treatment; this should be continued until hemoglobin values return to normal which could take up to 3 months. Hookworm infection can be treated with local  cryotherapy  when the hookworm is still in the skin.

10. Triple therapy with albendazole 400mg, pyrantel pamoate 200mg/kg and oxantel pamoate 20mg/kg showed cure rate of 84% when compared with other combinations

11. PREVENTION Do not walk barefoot in known infected areas Do not use raw sewage as fertilizer in agriculture Do not defecate in open but rather in toilets School-based mass deworming Public health education Sanitation