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Transcript
Cutaneous leishmaniasis in Syria Leishmaniasis Introduction Infectious disease caused by intracellular protozoan parasites of the genus Leishmania visceral, cutaneous, and mucocutaneous Visceral Leishmaniasis Known as kala azar Characterized by chronic recurrent fever splenomegaly pancytopenia weight loss high mortality Cutaneous leishmaniasis (CL) most abundant CL is caused by at least 12 different species of Leishmania, and each of them has its own characteristic, vectors, and reservoirs (CL) Presentation Single or multiple chronic skin ulcers Destructive mucocutaneous lesions, or Disseminated infection Mode of Transmission At least 70 different species of sandflies, small insects of the genus Phlebotomus The primary sandfly vectors of the Southwestern Asia region include Phlebotomus papatasi Phlebotomus sergenti CL Occurrence CL is found in most countries of the tropical and subtropical regions of the world 90% of all cases occur in only six countries: Afghanistan, Brazil, Iran, Peru, Saudi Arabia, and Syria CL Incidence Incidence fluctuates due to: new agricultural projects weather variability changes in reservoir densities, and annual sandfly patterns CL Incidence The annual incidence of CL throughout the world is 1 to 1.5 million cases with 350 million people at risk of getting the disease, only 300,000 cases are officially reported Most Important Infectious Agents Old World: Leishmania major Leishmania tropica Leishmania aethiopica New World: Leishmania braziliensis Leishmania mexicana Leishmania major Also known as the rural type Causes moist cutaneous lesions Occurs in southern districts of Syria Reservoir host is the rodent Psammomys obesus (Fat Sand Rat) Spreads zoonotically from desert rodents to man by sand fly Phlebotomus papatasi Leishmania major Incubation period is week to months Ulcers appear on the extremities Spontaneous healing occurs within 3 to 6 months, leaving a depigmented pitted scar Leishmania major Mode of Transmission Rodent Sandfly Human Leishmania major Occurrence Semi-arid climates hot dry season lasting 6 or more months temperature exceeding 35-40oC Rainfalls vary from 100mm- 600mm annually. Found in low-lying desert regions Soils are deep and friable but sufficiently cohesive for the construction of deep, durable, rodent burrows Leishmania tropica Known as urban CL, or “anthroponotic CL” Causes dry lesion Transmitted from person-to-person Humans and the domestic dogs serve as the reservoirs of infection Causative parasite in northern districts Transmitted by the sandfly Plebotomus sergenti Leishmania tropica Occurrence Spreads in areas of urban centers higher altitudes temperate climate arid, cold and warm weather Leishmania tropica Incubation period 2 months > a year Lesion is usually facial and begins as a pruritic, purplish nodule (the Aleppo button) then slowly enlarges and finally breaks down after 3 or 4 months Healing of the ulcers may require a year or more Leishmania tropica Mode of Transmission Sandfly Human Climate in Syria Two seasons: dry and hot summer (July hottest month) wet and cold winter (January coldest month) spring and fall mild with some rainfall Temperature declines from south to north (average annual temperature is 19.7oC in the south,and 17.2o in the north) The average annual precipitation is 100mm-1500mm Purpose of the Study To describe temporal and spatial patterns of disease and to characterize risk factors for exposure. CL Case Data Used in the Study Location All of Syria Damascus Suburbs, Aleppo Type of data Summary Count Summary Count Time Period 1990-1997 1994-1997 Frequency Monthly Monthly Spatial Units 14 Districts 1,824 Villages No. of Cases 112,484 32,076 Preliminary Results 18000 16000 14000 No. Cases 12000 10000 8000 6000 4000 2000 0 1990 1991 1992 1993 1994 Year 1995 1996 1997 Incidence Rate per 1000 in each district between 1990-1997 4.00 3.50 3.00 Damas City IR Damas Sub IR Daraa IR Suweida IR IR/1000 2.50 Qunaitra IR Homs IR Hama IR 2.00 Aleppo IR Idleb IR Lattakia IR 1.50 Tartous IR DeirAlZor IR Rakka IR 1.00 Hasakeh IR 0.50 0.00 1990 1991 1992 1993 1994 Years 1995 1996 1997 IR/1000 in Damascus Suburbs b/w 1994-1997 according to sex 3.50 Total IR Male IR 3.00 Female IR IR/1000 2.50 2.00 1.50 1.00 0.50 0.00 1994 1995 1996 Years 1997 IR/1000 in Aleppo b/w 1994-1997 according to sex 3.50 Total IR Male IR 3.00 Female IR IR/1000 2.50 2.00 1.50 1.00 0.50 0.00 1994 1995 1996 Year 1997 IR/100 in Damascus Suburbs b/w 1994-1997 according to age groups 6.00 IR<1 yr IR1-4 yr IR5-14 yr IR15+ yr 5.00 IR/1000 4.00 3.00 2.00 1.00 0.00 1994 1995 1996 Years 1997 IR/100 in Aleppo b/w 1994-1997 according to age groups 6.00 IR <1yr IR 1-4yrs 5.00 IR 5-14yrs IR 15+yrs IR/1000 4.00 3.00 2.00 1.00 0.00 1994 1995 1996 Year 1997 Damascus Suburbs Total Incidence Rates 0.45 TInc94 0.40 TInc95 0.35 TInc96 TInc97 IR/1000 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Jan Feb Mar Apr May Jun Jul Months Aug Sept Oct Nov Dec Damascus Suburbs Male Incidence Rates 0.45 MInc94 0.40 MInc95 0.35 MInc96 MInc97 IR/1000 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Jan Feb Mar Apr May Jun Jul Months Aug Sept Oct Nov Dec Damascus Suburbs Female Incidence Rates 0.45 FInc94 0.40 FInc95 0.35 FInc96 FInc97 IR/1000 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Jan Feb Mar Apr May Jun Jul Months Aug Sept Oct Nov Dec Aleppo Total Incidence Rates 0.40 TInc94 TInc95 0.35 TInc96 0.30 TInc97 IR/1000 0.25 0.20 0.15 0.10 0.05 0.00 Jan Feb Mar Apr May Jun Jul M onths Aug Sept Oct Nov Dec Aleppo Male Incidence Rates 0.45 MInc94 MInc95 0.40 MInc96 0.35 MInc97 IR /1000 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Jan Feb Mar Apr May Jun Jul M onths Aug Sept Oct Nov Dec Aleppo Female Incidence Rates 0.45 FInc94 0.40 FInc95 FInc96 0.35 FInc97 IR /1000 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Jan Feb Mar Apr May Jun Jul M onths Aug Sept Oct Nov Dec Conclusion There are few studies of the CL status in Syria despite the high rates More research is needed to identify the epidemiological relationship between vector, reservoir and host and to limit the spread of the disease.
