PARASITIC INFECTION

Nelson and Masters Williams, 2014

PARASITIC INFECTION  Co-evolved with human hosts  Adapted to evade immunity  Evolve in a manner that can enable migration to new hosts  Transmission  Direct—person to person, via fecal waste  Indirect—involves additional hosts or vectors Nelson and Masters Williams, 2014

SCHISTOSOMIASIS- CLINICAL PRESENTATION  Symptoms can vary  Type of worm involved  Location of parasite in the body  Considerable morbidity in intestines, liver and urinary tract  Some cases can lead to death Harrison’s Principles of Internal Medicine, Chapter 210, Malaria

SCHISTOSOMIASIS- CLINICAL PRESENTATION  Three phases of disease manifestation:  Invasion at site (rash/ dermatitis)  Acute schistosomiasis- fever, chills, muscle aches, lymph node enlargement, liver or spleen enlargement  Chronic schistosomiasis- for intestinal species may involve abdominal pain, bloody diarrhea, anemia  Children—anemia, malnutrition and learning disabilities Harrison’s Principles of Internal Medicine, Chapter 219

SCHISTOSOMIASIS- CLINICAL PRESENTATION

SCHISTOSOMIASIS- CLINICAL PRESENTATION  Urinary species (S. haematobium)  Frequent, painful, or bloody urine  Inflammation/ scarring of bladder  Bladder cancer may develop Harrison’s Principles of Internal Medicine, Chapter 219

ia.org/wiki/File:Schistosom a_mansoni_Life_Cycle.tif# /media/File:Schistosoma_ mansoni_Life_Cycle.tif

GLOBAL BURDEN OF SCHISTOSOMIASIS  240 million infected worldwide  700 million reside in endemic areas  Vast majority of burden in Africa  280,000 deaths annually  Approximately 2 million suffer severe outcomes including disfiguring disabilities, kidney disease, liver disease, and bladder cancer

GLOBAL DISTRIBUTION OF SCHISTOSOMIASIS Harrison’s Textbook of Medicine, 2015

SCHISTOSOMIASIS IN SAUDI ARABIA  S.mansoni is mainly found in the highland of the western region, and S.haematobium is mainly reported from Tabouk in the Northwest and from Baha and Mahael in the Low Land of the coastal plain in the Southwest region  Recent studies done in 2004 indicate that Saudis accounted for 61.2% of total infected cases and infection peaked at years  Ministry of Health statistical data in 2008 confirmed that Saudis are more infected than non-Saudis; the percentage of infection was 55.5 % and 45.5 % for Saudis and non-Saudis, respectively

CONTROL STRATEGIES  Education campaigns about risks of getting infected by bathing in fresh water lakes and ponds  Praziquantel is the primary form of treatment  A single dose of Praziquantel has been shown to reduce the severity of symptoms in cases of subsequent re- infection  A schistosomiasis vaccine is currently in the early stages of development by Sabin’s vaccine development team

CONTROL STRATEGIES  Preventive chemotherapy: “Rather than identifying every infected individual, large-scale preventive chemotherapy interventions assess entire communities for endemicity or ongoing transmission of the target helminthic diseases. The recommended drug or drug combination is then administered to all eligible members of the endemic communities.”  Praziquantel is the drug of choice. Usually co-administered with other anti-helminthic drugs such as Albendazole  Detailed procedures for mass screening and implementing preventive chemotherapy can be found at: =1 =1 World Malaria Report, 2014, WHO

CONTROL STRATEGIES  Schistosomiasis outbreaks can be identified by mapping the rates of blood in the urine of school-age children. If the rates are high, Praziquantel is distributed to the entire community at risk  Annual dosing of Praziquantel is sometimes recommended for areas at high risk for reinfection with the disease

CONTROL STRATEGIES IN SAUDI ARABIA  A national program for elimination of schistosomiasis was initiated in12 known endemic foci in Saudi Arabia in The strategies employed by this program are:  Active case detection and treatment by examination of % of the infected population once a year and % of school children in the same areas  Safe potable water supply and good sanitation are made available to infected communities.  Snail control using chemical molluscicides and mechanical methods  Health education istosomiasis_in_the_Kingdom_of_Saudi_Arabia_A_Reviewhttp:// istosomiasis_in_the_Kingdom_of_Saudi_Arabia_A_Review)