1	LEISHMANIASIS: AN OLD EMERGING DISEASE Presented By Jonathan M. Fradkin, DVM, MS Diplomate, ACVIM (SAIM), Major (Retired), U.S. Army Veterinary Corps San Antonio Veterinary Referral Specialists
2	Leishmaniasis… Endemic in Much of the World Uncommon but Increasing Concern in North America Increasing Concern with Increased Travel to Endemic Area n Military and Civilian Outbreak in North American Foxhounds Emerging Disease or Historic Problem
3	Leishmaniasis…Introduction Obligate Intercellular Protozoal Parasites - genus Leishmania Vector-Borne Disease - Bite of Female Phlebotamine Sandflies Spp. Phlebotomus = Old World Spp. Lutzomyia = New World There may be Exceptions Visceral and Cutaneous Disease in Man Visceral Disease in Dogs with Skin Lesions
4	Introduction…Human Forms Cutaneous-“Baghdad ulcer, Delhi boil or Bouton d’Orient” Generally Self-limiting Scarring & Debilitating Diffuse Cutaneous Defective Immunity Mucocutaneous -“Espundia” South America Severely Disfiguring Visceral- “Kala azar” Intermittent Fever, Wt. Loss, Hepatosplenomegaly High Mortality Form Dependent On Leishmanial Species VL- L. donovani si CL- L. major MCL- L. braziliensis Immune Status Geography Anthroponotic Forms Human Reservoir Zoonotic Forms/Reservoirs Dogs, Wild Canids, Rodents
5	Leishmaniasis…Cutaneous
6	Leishmania…Mucocutaneous
7	Leishmaniasis…Visceral
8	Introduction…Distribution (Human) Highly Endemic in much of the World Endemic in 88 Countries (16 Developed, 72 Developing) 90% of CL Afghanistan, Algeria, Brazil, Iran, Peru, Saudi Arabia, Syria 90% of VL in Bangladesh, Brazil, India, Nepal, Sudan Old World Mediterranean Basin, Portugal, Middle East/SouthWest Asia, Northern France, Switzerland, Netherlands New World Central & South America North America – Generally Limited to Imported Infections
9	"32 of 88 Endemic Countries..." 32 of 88 Endemic Countries Require Reporting 600,000 New Cases Per Year Reported 2 Million New Cases Per Year Estimated 1.5 Million Cutaneous 500,000 Visceral Global Distribution is Expanding Historic Factors: Malnutrition, War & Civil-Unrest, Refugees New Factors: HIV/AIDS, Deforestation, Urbanization Transmission: Vector, Vertical, Blood-borne
10	Introduction…Distribution (Canine) Dogs Serve as an Important Reservoir Visceral (& Cutaneous) L. infantum ≡ L. chagasi Dog Ownership in Endemic Areas Correlates with Increased Risk of Infection Effectively Reducing Canine Seroconversion Resulted in Reduced Human Seroconversion Canine Infection Rate Estimates 10-42% Seroprevalence in Endemic Areas Up to 67% PCR Prevalence
11	Leishmania…Lifecycle Diphasic protozoan parasites Two-Host Lifecycle: Vector Insect (Sandfly) And Reservoir Mammal Rodents Canids Humans
12	Leishmania…Sandfly Stages Female Sandfly Feeds from Infected Mammal Host Blood Contains Macrophage Infected by Amastigotes Amastigotes Differentiate into Promastigotes in Fly Midgut Promastigotes undergo Binary Fission, Migrate to Fly Proboscis Fly Feeds from Another Mammal Host Injects Promastigotes
13	Leishmania…Mammal Stages Motile Promastigotes Injected into Mammal Host Skin when Sand Fly Bites Promastigotes may Migrate in Skin Promastigotes ingested by Skin Macrophages (Langerhans cells) Transform to Amastigotes and Multiply (binary fission)
14	Leishmania…Mammal Stages Amastigotes Rupture Macrophages Infect New Cells Disease Spreads/Infected Macrophages & Amastigotes Circulate Disease Signs Dependent on Organs Affected New Sandfly Feeds on Host, Ingests Amastigotes
15	Leishmania…Transmission Factors Sandfly Vector - Limited flight range, most active at dawn and dusk Old World – Phlebotomus New World – Lutzomyia Central & South America Known Vectors North America – 4 Species Feed on Mammals Possible Vectors (?)
16	Leishmania…Transmission Factors Low Rate of Transmission Without Vector Human Congenital/Vertical Needle Sharing – Associated with HIV Co-infection Transfusion Canine Congenital/Vertical Transfusion Direct Contact/Fluid Exchange (Blood, Urine, Mating)
17	Leishmania…Canine Form Canine Visceral Leishmaniasis (CVL) Parasites Disseminate from Skin and Spread in Mononuclear Cells Bone Marrow Spleen and Liver Chronic, Possibly Fatal – Similar to Human VL but with Significant Cutaneous Lesion Only 10-20% of Exposed Dogs Become Clinically Infected Protective Immunity is Cell Mediated Many Asymptomatic Carriers
18	Leishmania…Canine Forms Subacute Form – Less than 5% of Dogs Acute Febrile Disease Chronic Form – Vast Majority Long Incubation Period – Months to up to 4 Years Signalment and History – most 3-7 Year Old. All Ages, Breeds, Both Genders Represented Certain Breeds Possibly More Susceptible o Foxhounds? o Large Breeds - GSD & Dobe? Travel History?
19	Leishmania…Canine Findings Chief Complaints Skin Lesions: ~50% Weight Loss: ~25% Partial Anorexia: ~17% Exercise Intolerance: ~11% Misc: Depression, Eye Disease, Epistaxis, PUPD, Diarrhea, Vomiting, Melena, Sneezing, Lameness Physical Exam Skin lesions: 81-89% Lymphadenopathy: 65-90% Pale mucous membranes: ~58% Ocular lesions:~18% Cachexia/Emaciation:10-47% Splenomegaly: 9.5-53% Fever: 4-36% Epistaxis: 6-10%
20	Leishmania…Clinical Dermatitis
21	Leishmania…Clinical Dermatitis
22	Leishmania…Clinical Signs
23	Leishmania…Canine Clin. Path. Nonspecific but Suggestive Hyperglobulinemia – 70-100% Hyperproteinemia – 63-72% Hypoalbuminemia – 68-94% Proteinuria – 71-85% Hyaline/Fine Granular Urinary Casts ~100% Nonregenerative anemia – 60-73% Thrombocytopenia – 29-50% Leukocytosis – ~24% Leukopenia – ~22% Azotemia – 16-45% Elevated Liver Enzymes – ~16-50%
24	Leishmania…Canine Differentials Other Infections Ehrlichiosis Hepatozoan Babesia Ectoparasites Demodex Sarcoptes FAD Neoplasia, esp. Lymphoma Immune Mediated Disease Allergy All May Have Similar Clinical Signs and Clinical Pathology Most are More Common Than Leishmania in North America and Rule-out May be Necessary before Leishmania becomes High on Your List
25	Leishmania…Diagnostic Steps Include on Differentials List Identify Suggestive Clinical Signs and Clinicopathology: None Pathognomonic All May be Seen with Other Disease Evaluate Risk Factors In North America, Disease is Pervasive in Kenneled Foxhound Populations-Serological Evidence of Exposure in 21 States + 2 Provinces Travel History to Endemic/Enzootic Areas Exposure to Other Animals with Disease or Travel History Specific Testing and Diagnostics – Rule-out Differentials & Confirm Leishmania
26	Leishmania…Confirm Diagnosis Identification of Amastigotes in FNA Lymph Nodes Dermal Lesions Ulcers or Nodules Bone Marrow Spleen Highly Specific - Nearly 100% with Trained Eye Immunohistochemical Stain Helpful Mod. to Low Sensitivity ~60% for Bone Marrow ~30% for LN, Spleen
27	Leishmania…Confirm Diagnosis Serology–Fundamental Role in Endemic Areas IFA – Gold Standard Identifies Exposure and Possible Infection Cut-off for Significance is Controversial - Generally >1:64 Titers do not Correlate to Disease Severity Organism Isolated from Dogs with Lower Titers Organism NOT Isolated from all Dogs with Higher Titers SeroNegative After Treatment Supports Remission Reconversion to Seropositive Supports Relapse IFA Cross Reacts with Chagas’ (T. cruzi) Other Methods – ELISA, Dot ELISA, FAST ELISA, Western Blot, Complement Fixation, Indirect Hemagglutination
28	Leishmania…Confirm Diagnosis PCR – Not All Methods or Samples Equal Blood = Most Convenient, Not as Good Skin Biopsy (Muzzle) Conjunctival Biopsy Bone Marrow/Lymph Node/Spleen Aspirate Culture – Not Routinely Available Bone Marrow/Lymph Node/Spleen Aspirate Skin Lesion Biopsy
29	Leishmania…CVL Treatment Goals Reducing Human Infection = Remove Dogs as Viable Reservoirs for Human Disease Culling Dog Populations Ineffective in Endemic Areas Preventing Sandfly Biting and Disease Transfer Restore Individual Pet to Good Clinical Health Likely to Have Recurrent Disease May Still Be Carrier
30	Leishmania…CVL Treatment HVL- Generally Responsive to Treatment Cure Limited by Drug Availability/Expense CVL- More Resistant to Therapy than HVL Rare Cure, May Result in Clinical Remission Dogs in Remission May Still Be Carriers Significant Public Health Concern in Nonendemic Areas Recent Increased Resistance to Protocols Some Concern that Use of Medications in Dogs may Increase Development of Resistance for HVL
31	Leishmania…CVL Treatment Pentavalent Antimonials – Inhibit Leishmania Enzymes for Glycolytic & Fatty Acid Oxidation Meglumine antimoniate (Glucantime^®) – Europe, IM/SQ Sodium stibogluconate (Pentosam^®) – Europe, IV/SQ USA = Available by Investigational New Drug Protocol (CDC) Allopurinol – Inhibits Leishmania Protein Synthesis Oral, Best Used in Combination Therapy with Other Meds Aminosidine – Inhibits Leishmania Protein Synthesis SQ/IM for Cutaneous Lesions, Toxicity Limits Use
32	Leishmania…CVL Treatment Amphotericin B – Binds Sterols to Increase Leishmanial Membrane Permeability Extremely Effective but Toxicity Limits Use, Does Not Cure CVL Lipid Formulation is the “Big Gun” for HVL Some Recommend Against it for CVL Out of Concern for HVL Pentamidine – Damages Leishmania DNA Antifungals, Metronidazole, & Others Under Evaluation Combinations Pentavalent antimony + Allopurinol Pentavalent antimony + Amphotericin B Others
33	Leishmania…CVL Prevention Vaccination – Not Currently Available Protecting Individual Dogs From Sandflies Keep Indoors at Dawn/Dusk Deltamethrin Collars (approved European product) In Endemic Areas – Reduced Seroconversion of Dogs & Children Repellants and Insecticides Protect Individual People from Sandflies Limit Activities when Sandflies Active Use of Nets, Screens, Repellants – Limited Effect
34	Leishmania…Military Issues Significant Concern about Risk of Accidental Military Import of Leishmaniasis Movement of Military Personnel Movement of Military Pets Movement of Military Working Dogs “Leishmaniasis has been transmitted to North America via pets from military personnel formerly stationed in foreign locations” JAVMA, June 15, 2000
35	Leishmania…Military Personnel OIF/OEF Over 250,000 Personnel Deployed Deployment Rotations Began Fall 2002, Data Thru April 2004 Cutaneous Leishmaniasis – 522 cases L. major, Diverse Population of Personnel Visceral Leishmaniasis – 2 cases (OEF) L. infantum, Special Forces Soldiers in Afghanistan Desert Storm over 500,000 Personnel Deployed 1990-91 Cutaneous Leishmaniasis – 20 cases L. major, L. tropica Visceral Leishmaniasis – 12 cases L.tropica, Viscerotropic form of disease Leishmaniasis type not reported – 9 cases
36	Leishmania…Military Pets Authorized Pets in Southern Europe One Confirmed Case of Transmission to North America from a Military Pet (2001) to Another Pet Seroprevalence up to 75% Among Military Pets in Parts of Mediterranean Basin – Higher than General Pet Population, Why? Authorized Pets - Other US Bases (Japan, Korea, other) Lower Risk – Fewer Service Families, Less Leishmania ISSUES Return of Family Pets Can Not be Prevented Local Veterinarian will Sign HC if VCO does not. Return of Unauthorized OIF/OEF “Pets”/Mascots Enforcement Often Thwarted by Non-Governmental Agencies. Pets Are Not Just a Military Problem Expatriates, Overseas Workers, Diplomats & Staff, Vendors
37	Leishmania…Military Work Dogs Stringent Preventive Medicine Program Only Healthy MWDs Deploy – Decreased Risk Of Infection If Arrive With Healthy Immune System Routine Monthly Oral HW & RW preventative, Topical Acaracide with IGR Mandatory Supplement – Instituted 2001 4% Deltamethrin collars in Leishmaniasis Endemic Areas (Scalibor® , Off Label=Adams^TMDeltaForce^TM, Happy Jack ® Novation^TM) Oral Doxycycline + Amitraz Collar or Daily Acaracide/repellant in High Tick-Borne Disease Areas Results – Lower Sero/PCR-prevelance in MWDs
38	Leishmania…Military Work Dogs Leishmaniasis’s Impact on MWDs with Mediterranean Basin Exposure (Killian J) Retrospective Study of MWDs assigned in Endemic Areas (1992 to 2002) 64 MWDs – 57 available Medical Records Cases = 0/36 PCR Positive [21 no tissue available] Probable Cases = 0/32 IFAT Seropositive(≥1:16) [25 no serum available] Suspect Cases = 16/57 = 28% with 2 or More Clinical Signs Consistent with Canine Leishmaniasis
39	Leishmania…Military Work Dogs Leishmaniasis’s Impact on MWDs …(Killian J) Suspect Cases ≥ 2 CanL Clinical Signs (Neg Titer) 16/57 = 28% No Correlation to Duration of Exposure Conclusion=Not Significant 30-75% Titer or PCR Prevalence in Civilian Dogs of Subject Area
40	LEISHMANIASIS: QUESTIONS Presented By Jonathan M. Fradkin, DVM, MS Diplomate, ACVIM (SAIM), Major (Retired), U.S. Army Veterinary Corps San Antonio Veterinary Referral Specialists
41	Leishmania…Additional References Lay J, DoD MMSR, 2004;10(1):2-5. Magill A,et al, NEJM, 1993;328(19)1383-7. Orndorff G, et al, Mil Med, 2000;165(1):29-32. Schantz P, et al, JAVMA, 2005;226(8):1316-22. Policy Memorandum, DODVSA, 17 May 2004. Handbook of Veterinary Care of the MWD, DODMWDVS, 5 Mar 2004. Bray R, Parassitologia, 1987;29(2-3):175-9.
42	The mission of the ACVIM Foundation is to enhance the diagnosis, treatment, and prevention of disease in all animals.
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