By region, Caraga or Region 13 ranked first in Mindanao and Region 8 in the Visayas. By province, Agusan del Sur is first on the list, followed by Northern Samar and then Eastern Samar. Overall, the prevalence rate among males is higher than that of females suggesting the occupational hazard of farming and fishing among the males. The higher exposure among farmers and fishermen is also borne out by the age distribution of the disease. Prevalence remains consistently high among the adults compared with the younger age groups.
The life cycle is common to all species with a sexual generation in vascular system of the definitive host (human) and an asexual generation in the intermediate hosts (snails).
Different Genera of the snails
Schistosomiasis is transmitted by contact with contaminated fresh water (lakes and ponds, rivers, dams) inhabited by snails carrying the parasite. Swimming, bathing, wadding, fishing and even domestic chores such as laundry and herding livestock can put people at risk of contracting the disease.
Larvae emerge from the snails and swim in the water until they come into contact with an individual and penetrate the skin.
4) after penetration schistosomula migrate to the lungs (in 3-4 days), and after penetration in the pulmonary capillaries they are carried to the systemic circulation and to the portal system. In the hepatic circulation schistosomes mature to adult, and in pairs they migrate to the mesenteric veins ( S.mansoni , S.japonicum , S.mekongi , S.intercalatum ) and to the the veins of the vesical and pelvic plexuses ( S.haematobium ). After 35 days ( S.japonicum , S.mansoni ) and 70 days ( S.haematobium ) embryonated eggs are excreted in faeces and/or urine. In the body, the larvae develop into adult schistosomes, which live in the blood vessels. The females release eggs, some of which are passed out of the body in the urine or faeces. Others are trapped in body tissues, causing an immune reaction. In urinary schistosomiasis, there is progressive damage to the bladder, ureters and kidneys. In intestinal schistosomiasis, there is progressive enlargement of the liver and spleen, intestinal damage, and hypertension of the abdominal blood vessels.
Once inside the body, the larvae develop into an adult schistosomes: male and female worms which pair up and live together in the blood vessels for years. Female worms release thousands of eggs which are passed out of the body in the urine and feces. Others are trapped in body tissues, causing an immune reaction. If people urinate or defecate in bodies of freshwater, the eggs migrate to snails where they eventually hatch and begin the cycle again. Some Schistosoma eggs, however, remain trapped in the body and migrate to specific organs (depending on the type of parasite) where they can inflict major damage. In urinary schistosomiasis, there is progressive damage to the bladder, ureters and kidneys. Urinary schistosomiasis causes scarring and tearing of the bladder and kidneys, and can lead to bladder cancer. Intestinal schistosomiasis develops slowly. There is progressive enlargement of the liver and spleen, intestinal damage, and hypertension of the abdominal blood vessels. Intestinal schistosomiasis, causing abdominal bleeding and damage to the intestines. A major indicator of the disease is blood in the urine and/or feces.
Not uncommonly found in male genital organs , but the significance of this finding has not yet been clarified.
Symptoms for the disease vary depending on the type of worm involved and the location of the parasite inside the body, and can include: Initial itching and rash at infection site (“swimmer’s itch”) Frequent, painful or bloody urine Abdominal pain and bloody diarrhea Anemia Fever, chills and muscle aches Inflammation and scarring of the bladder Lymph node enlargement Enlargement of the liver or spleen Secondary blood disorders in cases of colon damage If infection persists, bladder cancer may eventually develop in some cases Children with repeated infection can develop anemia, malnutrition and learning disabilities
The number of identified endemic areas has increased in the previous years due to active surveillance of human cases and snail vector surveillance through environmental mapping of areas with positive snail colonies.
Serologic tests may not be as sensitive or specific.
Control of schistosomiasis is difficult. The control of snails is critical; environmental sanitation, safety of supply water and education are essential.
Untreated piped water coming directly from canals, lakes, rivers, streams or springs may contain cercariae, but heating bathing water to 50°C (122°F) for 5 minutes or filtering water with fine-mesh filters can eliminate the risk of infection. If such measures are not feasible, travellers should be advised to allow bathing water to stand for 2 days because cercariae rarely remain infective longer than 24 hours. Swimming in adequately chlorinated swimming pools is virtually always safe, even in endemic countries. Vigorous towel drying after accidental exposure to water has been suggested as a way to remove cercariae in the process of skin penetration; however, this may prevent only some infections and should not be recommended to travellers as a preventive measure. Although topical application of the insect repellent DEET can block penetrating cercariae, the effect is short lived and cannot reliably prevent infection.
Upon return from foreign travel, those who may have been exposed to schistosome-infested freshwater should be advised to undergo screening tests. Because serologic tests are more sensitive than microscopic examination of stool and urine for eggs, previously uninfected but potentially exposed travellers should be tested for antibodies to schistosomes if microscopic examination of stool and urine for eggs is negative or not available. CDC performs a screening ELISA that is 99%, 90%, and 50% sensitive for Schistosoma mansoni , S. haematobium , and S. japonicum , respectively, and a confirmatory, species-specific immunoblot that is at least 95% sensitive and 99% specific for all three species. Serologic tests performed in commercial laboratories may not be as sensitive or specific.
Praziquantel is the drug of choice for all species of Schistosoma . Oxamniquine has been effective in treating infections caused by S. mansoni .
PerPetual Succour HoSPital Department of Family & Community Medicine GRANDROUND PRESENTATION BY: LIZA D. MARIPOSQUE, M.D. 2nd Year Famed Resident February 2010
OBJECTIVES To present a case of a 67 yrs old farmer with Schistosoma. To discuss Schistosoma haematobium specie. Epidemiology & Etiology Pathophysiology Diagnostic tools Treatment & Preventions
B.A., 67 y.o., male, married, farmer from Bukidnon, presently residing in Cabancalan, Mandaue City admitted due to hypogastric pain and inability to urinate.Travel History: Agusan del Sur in 1987 as a farmer then to Bukidnon.
PAST MEDICAL HISTORY HPN – uncontrolled (-) DM 2, Bronchial asthma PREVIOUS HOSPITALIZATION: 2006 – Herniorrhaphy L (Kidapawan City) Smoker x 20 pack yrs Alcohol beverage drinker No Food & Drug allergies
HISTORY OF PRESENT ILLNESS 1 yr PTA-Difficulty voiding 4 days PTA- difficulty in urination 2 days PTA - sought consult - Advised UTZ - KUB -Rx Rowatinex
ABDOMEN: Flat, hyperactive bowel sound, no hepatomegaly, soft, nontender, no mass palpated.GUT: post-op infraumbilical scar, enlarged R scrotum, no erythema, nontender; tenderness hypogastric area (+) KPSEXTRIMITIES: No edema, strong pulses.CNS: within normal limitDRE: No skin tags, tight sphincter tone, no mass, prostate gland not enlarged, (+) fecal material on rectal vault, (-) blood on the examining finger.
ADMITTING IMPRESSION Nephrolithiasis Hypertensive Urgency Pneumonia Inguinal Hernia, R
UTZ Whole Abdomen Echogenic lace-like pattern of the liver consistent with Schistosomiasis. Gallbladder, common duct, pancreas, spleen – negative. KUB – negative. NORMAL SIZE Prostate gland, 1.0cm cyst in the L lobe. Aorta – normal in course & caliber.
P: hypogastric pain, inability to urinate, BPS: hypogastric pain, slightly dyspnicO: conscious, coherent & not in respiratory distress. BP: 130/70-160/70 mmHg PR: 72-85 bpm RR: 19-20 cpm T: 36-37 0C Total Fluid Intake: 300 UO: 1,050 cc
Assessment: Schistosomiasis (S. haematobium) ARF 2ndary to Hypertensive Nephrosclerosis vs. Uric Acid Nephropathy HPN CAP, Moderate Risk
Plan: Cefuroxime 750 mg IVTT OD. Allopurinol 100 mg 1 tab OD. Dolcet 1tab TID. All other meds continued. Foley Bag Catheter inserted. Referred to Nephrologist for co-mgt. Additional labs requested …..
Ca 7.85 mg/dl (n.v.8.4-10.3) BUN 104 mg/dl (n.v. 7-18) Phosphorus 6.30 mg/dl (2.5-4.7)
O2 inhalation @ 2 Lpm. IVF changed into D5 0.3% NaCl @ 10 gtt/min. I & O q hourly. Hold Allopurinol & Captopril.
P: hypogastric pain, inability to urinate, BP, dyspnea, creaS: w/ mild hypogastric pain, no dyspneaO: conscious, coherent & not in respiratory distress. BP: 130/70-150/90 mmHg PR: 68-74 bpm RR: 19-20 cpm T: 36-36.8 0C Total Fluid Intake: 2590 cc UO: 2,705 cc
Assessment: Schistosomiasis (S. haematobium) ARF 2ndary to Hypertensive Nephrosclerosis vs. Uric Acid Nephropathy HCVD CAP, Moderate Risk
Plan: CaCO3 (Tums) 500mg 1tab TID. NaHCO3 Gr. X 650mg 2tabs TID. Ranitidine IV shifted to P.O 150mg 1tab OD. Hold Nicardipine drip. Cefuroxime IV shifted to P.O 250mg 1tab OD. Increase IVF rate to 20gtt/min.
Repeat Crea on 12/31/09. PSA determination requested. For infectious consult…
Infectious ConsultA: Schistosoma probably due to S. hematobiumP: > Rectal Imprint > Praziquantel 25mg/kg in 2 divided doses at 4 hours interval. > Referral to DOH.
Plan: crea, BP,S: No complaintsO: conscious, coherent & not in respiratory distress.BP: 130/80-140/80 mmHg PR: 60-65 bpmRR: 20-21 cpm T: 36.2-36.5 0CTotal Fluid Intake: 1660 cc UO: 480cc
Assessment: Schistosomiasis (S. haematobium) ARF 2ndary to Uric Acid Nephropathy HCVD CAP, Moderate Risk
Plan: Discharge against medical advised. Take home meds: Cefuroxime 250 mg 1tab OD x 7 days. NaHCO3 Gr. X 2tabs TID x 1 month. CaCa3 (Tums) 500mg 1tab TID. Amlodepine 10mg 1tab OD as maintenance. Advised and referred to DOH Ff-up with APs.
What is Schistosomiasis? Schistosomiasis or bilharzia or Snail Fever It is a parasitic disease common among farmers, fishermen and their families in Africa & certain parts of the Philippines. parasitic disease that leads to chronic ill-health. caused by trematode flatworms of the genus Schistosoma.
Parasitic disease carried by fresh water snails infected with one of the five varieties of the parasite Schistosoma. Urinary schistosomiasis - caused by Schistosoma haematobium Intestinal schistosomiasis - S. intercalatum, S. mansoni, S. japonicum, and S. mekongi.
Epidemiology: affects at least 200 million people worldwide, >700 million people live in endemic areas. Prevalent in 74 countries worldwide, but over half of all documented cases are in Africa
Prevalence: tropical areas sub-tropical areas poor communities without potable water and adequate sanitation.
Endemic in 12 regions in the Philippines. Affecting 28 of the 79 provinces in the country.
Morbidity rate- declined from 17.5 cases/100,000 population in 1997 to 5.6/100,000 in 2000. Case fatality ratio has also continued to decline from 0.9 death/100,000 population in 1980 to 0.3/100,000 in 1997 and has reached a plateau since then.
PATHOPHYSIOLOGY Life cycle - common to all species sexual generation in vascular system of the definitive host (human) asexual generation in the intermediate hosts (snails).
1) Embrionated eggs are discharged in faeces and urine. in water miracidia hatch from the egg and penetrate the intermediate hosts:
S.haematobium: adult schistosomes live in pairs in the pelvic veins (especially in the venous plexus surrounding the bladder). Males = 10-15 mm in lenght by 0.8-1 mm in diameter. have a ventral infolding from the ventral sucker to the posterior end forming the gynecophoric canal.
Females = slender ( 0.25 mm in diameter) and longer (up to 20 mm in lenght) Each female lays about 150 eggs per day.
Schistosoma haematobium eggs Concentrated in the tissue of the bladder. the main agent of pathology inducing granuloma formation Hyperplasia of the mucosa fibrosis and calcification polyps formation in bladder & ureter stenosis.Hydronephrosis Bladder Cancer
Not uncommonly found in male genital organs. A relationship between the presence of eggs in seminal fluid and male infertility has not been demonstrated. The damage of the seminal vescicles seems to correlate with the degree of the obstructive uropathy. Less commonly affected are the prostate, the testes and the epididymis.
Manifestations: Initial itching and rash at infection site (“swimmer’s itch”) Fever, chills and muscle aches Frequent, painful or bloody urine. Bladder, ureteral fibrosis and hydronephrosis - advanced cases Bladder cancer - late-stage complications.
Diagnosis - identification of eggs in urinary sediment. viable eggs contain a motile miracidium.
Serological tests - useful for travellers returning from endemic areas and in patients with light or ectopic infection, with no detectable eggs in the faeces, urine or intestinal biopsies (i.e. hepatic, CNS infections). (+) test may reflect previous exposure to the agent rather than an active infection. a slow decrease in titer - after effective treatment
Treatment & Preventions Environmental sanitation Safety of supply water Education snail control with spraying & drip feeding. Molluscisciding drip feeding
Education – the risk of getting infected by bathing in fresh water lakes and ponds/dams. Heating bathing water to 50°C (122°F) for 5 minutes or filtering water with fine-mesh filters. Allow bathing water to stand for 2 days because cercariae rarely remain infective longer than 24 hrs.
Swimming in adequately chlorinated pools. Vigorous towel drying after accidental exposure. Topical application of the insect repellent DEET can block penetrating cercariae.
A schistosomiasis vaccine is currently developed by Sabin’s vaccine development team Praziquantel – DOC; A single dose of it has been shown to reduce the severity of symptoms in cases of subsequent re-infection. PZQ 40 mg/kg (WHO Recommendation) Oxamniquine has been effective in treating infections caused by S. mansoni. Metrifonate & Albendazol - alternative
Oxamniquine and Metrifonate. Albendazol also is used