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  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 MALARIA  Globally, estimated 3.3 billion people at risk of being infected with malaria and developing disease  1.2 billion are at high risk (>1 in 1000 chance of getting malaria in a year)  198 million cases are estimated to have occurred globally in 2013, leading to 584,000 deaths.  About 90% of all malaria deaths occur in Africa World Malaria Report WHO

TRENDS IN GLOBAL MALARIA DEATHS BY AGE AND GEOGRAPHICAL REGION, (12) /fulltext)

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HIGH RISK GROUPS  Children under the age of 5 account for 75% of the malaria deaths globally  Among pregnant women, malaria is associated with:  High parasitemia with anemia  Hypoglycemia  Acute pulmonary edema  Fetal distress, premature labor, stillbirth and low birth weight are common  Immigrants from endemic areas living in non-endemic areas who return back home World Malaria Report, 2014, WHO; Lancet, 2012; 379:

HIGH RISK GROUPS  Malara exacts a heavy burden on the poorest and most vulnerable communities  “Within endemic countries, the poorest and most marginalized communities are the most severely affected, having the highest risks associated with malaria, and the least access to effective services for prevention, diagnosis and treatment” World Malaria Report, 2014, WHO

MALARIA IN SAUDI ARABIA  Anopheles arabiensis is currently the only known vector of malaria in Saudi Arabia  Abundance of An. Arabiensis typically peaks following the rains, when multiple breeding sites appear  An. Arabiensis rests and feeds outdoors as well as indoors. Hence, vector control methods targeting the human home alone, such as indoor residual spraying (IRS) and insecticide treated nets (ITNs or LLINs) are not sufficient to control this vector

MALARIA IN SAUDI ARABIA  Perennial mountain streams and oases in the southern provinces of Saudi Arabia is a region where human communities and vector populations coincide, and from where most malaria cases are reported

MALARIA IN SAUDI ARABIA  Saudi Arabia – among 34 countries worldwide with policy and programming to eliminate malaria  Distributed sufficient insecticide treated nets (ITNs) in to protect > 60% of the high risk population  Achieved > 75% decrease in the incidence of confirmed malaria cases between 2000 and 2013, and reported only 34 indigenous cases in 2013  Persists in Aseer and Jazan provinces, bordering Yemen World Malaria Report, 2014, WHO.

MALARIA IN SAUDI ARABIA % cases are P. vivax by year in Saudi Arabia

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PREVENTION STRATEGIES  Malaria interventions- highly effective and affordable!  Vector control by Insecticide Treated Nets (ITNs) or Indoor Residual Spraying  Chemoprevention  Case management World Malaria Report, 2014, WHO

PREVENTION STRATEGIES- ITNS  ITNs are estimated to reduce malaria mortality rates by 55% in children under 5 years of age in sub-Saharan Africa  In children, prevent not only malaria deaths, but also reduce deaths from other causes exacerbated by malaria (eg. acute respiratory infection, low birth weight and malnutrition)  ITNs reduce incidence of malaria cases by 50%  In pregnant women, ITNs are also efficacious in reducing maternal anemia, placental infection and low birth weight World Malaria Report, 2014, WHO

PREVENTION STRATEGIES- IRS  IRS has been adopted as policy for vector control in 90 countries worldwide. For programmes conducting Indoor Residual Spraying (IRS), WHO recommends the spraying of at least 80% (ideally 100%) of houses, structures and units in the target area in any round of spraying  Pyrethroids were the primary class of insecticides used by countries implementing IRS, followed by carbamates and organophosphate. The insecticide used must be rotated annually to preserve effectiveness of current compounds World Malaria Report, 2014, WHO

PREVENTION STRATEGIES- CHEMOPREVENTION  Malaria can have devastating consequences in pregnant women and in children. In areas of high transmission, WHO recommends targeting these high-risk groups with chemoprevention strategies  Intermittent preventive treatment in pregnant women with Sulphadoxine-Pyrimethamine (SP), delivered at each scheduled antenatal care visit during second and third trimester of pregnancy reduces severe maternal anemia, low birth weight and perinatal mortality World Malaria Report, 2014, WHO

PREVENTION STRATEGIES- CHEMOPREVENTION  Amodiaquine plus SP for children given in seasons of high transmission. Works by maintaining therapeutic anti- malarial drug concentrations in the blood during periods of greatest malaria risk  Intermittent preventive treatment for infants (IPTi) with SP, delivered at routing childhood immunization clinics, provides protection in the first year of life against clinical malaria and anemia; reduces hospital admission for infants with malaria and admissions for all causes World Malaria Report, 2014, WHO

DIAGNOSIS AND TREATMENT  In most malaria-endemic areas, less than half of patients with suspected malaria infection are actually infected with a malaria parasite  Examination of blood smear by microscopy or rapid diagnostic test (RDT)- confirm infection in suspected cases of malaria  Artemisinin-based combination therapy (ACT) treatment of uncomplicated P.falciparum malaria has been estimated to reduce malaria mortality in children aged 1-23 months by 99% (range %) and in children months by 97% (range: 86-99%)  Use of Artemisinin monotherapies fosters resistance World Malaria Report, 2014, WHO