LEISHMANIA in dogs: life cycle, occurrence and zoonotic aspects Stig Milan Thamsborg Professor, DVM, PhD KU-SUND, [email protected] Heidi L. Enemark Seniorforsker, DVM, PhD DTU National Veterinary Institute, [email protected] Leishmaniosis One of the most important vector-borne diseases, endemic in the Mediterranean Bassin but possibly spreading in countries in Central Europe and North The vectors arewww.onleish.org Phlebotomus spp. (“sandflies” = mosquitoes) (e.g. P. perniciosus ) - multiplies in the gut of The agent - Leishmania vectors and are trans- infantum inside a mitted by bites or faeces macrophage www.onleish.org Hosts (vertebrates): dogs and other carnivores + homo 2 © Prof. Luis de Carvalho & Prof. Guadalupe Miró Corrales - ESCCAP Forum Lisbon 2012 Leishmaniasis in a global context 3 Leishmania in dogs, including zoonotic aspects • Etiolgy – The parasite – Vectors • Biology and epidemiology – Life cycle – Hosts – Transmission – Prevalence • Pathogenesis and clinics • Zoonotic aspects • Diagnostics • Control – Therapy – Prevention • Re-cap and discussion 4 Etiology 1 Sub-phylum: Flagellates Order Family Genus Diplomonadida Hexamitidae Giardia intestinalis (in organs) Trichomonadida Trichomonadidae Tritrichomonas foetus (organs) Trichomonas gallinae Monocercomonadidae Histomonas meleagridis Trypanosomatida Trypanosomatidae Trypanosoma spp. (blood+lymphatic Leishmania spp. systems, tissues) 5 Etiology 2 Morphology ( Leishmania and Trypanosoma) Different forms/stages: a) Promastigot 10-15 µm (Leishmania in vector) b) Epimastigot c) Trypomastigot (typical form in blood of final host) d) Amastigot 2-3 µm (Leishmania in RES in final host) a)+b) commonly found in vectors 6 Etiology 3 Leishmania spp. in dogs/cats in Europe Agent Vectors Final hosts Leishmania Phlebotomus spp. (sand Dog, fox jackal, rodents infantum flies) e.g.: cats, a.o. mammals + (s. L. chagasi i P. perniciosus , P. ariasi, homo Americas) P. perfiliewi, P. neglectus, (more genotypes) P. tobbi, P. langeroni Leishmania P. sergenti, P. arabicus Dog+homo tropica – cutan form in dogsh (rare) (Orient sores) The species can not be differentiated by morphology but clinics, vectors etc. and recently, PCR!! Blurry! 7 Etiology 4 Vector: Phlebotomus spp. (sandflies) • Sandflies(Phlebotomus spp.) are mosquitoes (2-4 mm) • Egg are laid in soil rich in organic matter, e.g., garbage • Females eat blood • Fourage during night, most activity in mornings and >18 oC; right after sunset • During day hiding in crevices and holes, e.g. animal holes, walls, rocks, trees or sheds. • Widespread in Mediterranean area, Africa and Middle East • Local endemic foci in North France, South Germany and Switzerland (e.g. P. mascittii ) • http://www.ecdc.europa.eu/en/healthtopics/vectors/vector -maps/Pages/VBORNET_maps_sandflies.aspx • Parasite development in vector: 1-2 weeks at 18 oC 8 Biology and transmission 1 Life cycle Multiplication: - as extracellular promastigots in the gut of sandflies - as intracellular amastigots in dogs 9 Biology and transmission 2 Dogs comprise the main reservoir in Europe, but other reservoir host are present… Fox (Marín-Iniesta et al ., 1982) Wolf (Beck et al. , 2008) Genet (Sobrino et al., 2008) Lynx (Sobrino et al., 2008) Desmer (Sobrino et al., 2008) Rat (Morillas et al ., 1985) Cat (Maroli, 2007) 10 © Prof. Luis de Carvalho & Prof. Guadalupe Miró Corrales - ESCCAP Forum Lisbon 2012 Biology and transmission 3 Dokumented but probably limited importance : • Vertical (Rosypal, 2005; Pangrazio et al. 2009; Boggiatto et al. 2011) • Blood transfusion (Owens et al., 2001, De Freitas et al., 2006; Tabar et al, 2008) • Venereal transmission (Silva et al. 2009) * Solano Gallego et al, 2011 • Other arthropods ?? (increasing evidence) – fleas, ticks (Coutinho et al. 2007; Paz et al. 2010; Dantas-Torres, 2011) 11 © Prof. Luis de Carvalho & Prof. Guadalupe Miró Corrales - ESCCAP Forum Lisbon 2012 Biology and transmission 4 Distribution in dogs in Europe • Black line represents north limit of sandflies and endemic leishmaniosis • Prevalence of infection in Med. Bassin: 1-40% (Ab), some places 80% (PCR) • 2.5 mio. infected dogs (Baneth, 2007) • Most likely spreading North, e.g. in Italian Alps but also spreading within endemic areas • Single autochtonous cases in D, F, UK, B, NL in dogs (© ESCCAP) 12 Biology and transmission 5 Epidemiology • New findings in Leishmania endemic areas : – fast and efficient spread when environmental factors are optimal, e.g., high prevalence of vectors – more widespread than expected (PCR) but only few become clinically afffected • Cats: importance? (60% PCR+ in Sicily) • North Europe – travelling: NL 58000/year South; risc 0.027-0.23% (Teske et al. 2002) – import of infected dogs – non-vectorborne transmission – (USA: foxhounds in NYS) 13 Pathogenesis and clinics 1 Leishmania infantum in dogs • Pathogenesis – infects macrophages in the skin after bite – chanker formation and spread with blood/lymph to mainly RES – granulomatous inflammation with necrosis and tissue destruction when amastigotes proliferate in macrophages – multi-systemic immun-mediated pathology depending on Th1/Th2 balance – glomerulonephritis, polymyositis, haemostasis problems a.o. • Clinics – varies with strain and host genetics – visceral form (liver,spleen, bone marrow) but SKIN LESIONS dominates commonly Top formation of goggles – typically: severe sacling with ulcers, alopecia, evt. pustules and nodules in skin initially in visceral form – poor body condition, generalised muscle atrophy, swelling of lymph nodes – also: fever, anaemia, cachexia – eye disease and kidney failure • Incubation period: 3 mths to 7 years • Chronic course 14 Patogenese og klinik 2 Infection versus disease NO clinical signs Clinical signs AND/OR No laboratory Infection laboratory abnormalities abnormalities confirmed 15 © Prof. Luis de Carvalho & Prof. Guadalupe Miró Corrales - ESCCAP Forum Lisbon 2012 Patogenese og klinik 3 Tip of the iceberg (<10%) © G. Miró Clinical cases (always) and sero+ PCR+ Distribution of leishmaniosis in a dog population Sero+ Rarely PCR- in an endemic area (Baneth et al, 2008) G. Miró16 Pathogenesis and clinics 3 Severe disease in some dogs! • Rapid development with clinical disease in some dogs that do not develop protective cell-mediated immunity (CMI) despite solid humoral response • Antibody response positively correlated with severity of disease and parasite density • Other dogs remain infected for years with symptoms and develop protective CMI • Function of macrophages very important • Immune response is mixed Th1/Th2 under strong genetic regulation: • Genetically resistant: Ibizean hound • Genetically susceptible: German shepherd, rottweiler, cocker spaniel, and boxer • Single genes and SNPs identified • Dog with/without symptoms are INFECTIVE for sandflies but ill dogs much more so!! G. Miró17 Zoonotic aspects 1 18 Zoonotic aspects 2 Global distribution in humans L. donovani + L. infantum/chagasi (visceral) L. tropica + L. major 19 Zoonotic aspects 3 Leishmaniosis in humans • 90% of human cases of cutan leishmaniosis in Afghanistan, Brazil, Iran, Peru, Saudi Arabia, and Syria (WHO) • L. major : >700 cases during war in Iraq; L. tropica : visceral cases after Operation Desert Storm • More than 90% of human cases of visceral leishmaniosis in India, Bangladesh, Nepal, Sudan, and Brazil (WHO). Continued spread to new areas due to HIV • Co-infections of HIV and visceral leishmaniosis are reported from 34 countries in Africa, Asia, Europe, and S-America. • 70% of human cases among adults i S-E associated with HIV (WHO) • Estimate: 700 new human cases per year in S-E • Leishmaniosis is common among travellers/tourist of S-E • Human diagnostics in DK in 2011 (Overlæge Jørgen Kurtzhals): – 6 microscopy (4719 malaria; 6145 cryptosporidiose) – 104 antibodies (531 malaria-species; 1097 toxoplasma- schistosomes-echinococcosis) 20 Diagnostics 1 Diagnostics, dogs • Tentative diagnosis: – History and clinics (obs. demodicose) – Lab test: haemogram, biochemistry and urine analysis • Detection of parasites – Smear from marrow or lymph node/Giemsa staining ( DTU-Vet ) – Aspirate lymph node, marrow, blood, conjunctiva or skin biopsy : PCR or qPCR (most sensitive + species)( Idexx ) – Histology on skin biopsy (sensitivity increased by immuno-histochemistry) – (in vitro culture to promastigote stage) • Indirecte detection - serology – At earliest 8-12 weeks after infection – IFAT, ELISA ( Laboklin )(semi-quantiative test to follow treatement success) – Snap test in clinics (first detection) 21 Diagnostics 2 Clinical pathology in dogs • Blood: – normochrom, normycytic anaemia – evt. thrombocytopenia – leukopenia – hyperglobulinaemia – hypoalbumimaemia • Biochemistry: – Varying degrees of uraemia – Increase protein/creatinin • Urin analysis – Proteinuri – Haematuri 22 Control 1 Chemotherapy of leishmaniosis in dogs Drug Type Dosage Adm. Side effects Meglumine pentavalent 75-100 mg/kg Sc Lokcal swellings antimoniate antimoniate daily in 4-8 Resistance in vitro (enzyme weeks inhibition) Allopurinol purin analog 10-20 mg/kg (2- Po Cases of nephrolithiasis (inhibit RNA) 3 x day) in 6-18 (xanthin) mths. (min. 20 Often medication rest of mg/kg daily) life! Miltefosine alkylophospho- 2 mg/kg daily in Po GI problems if not fed lipid 4 weeks with other diet (damage to membranes) Combinations: meglumin+allopurinol miltefosine+allopurinol + additional symptomatic treatments and correct diet 23 Control 2 Aspects of control in dogs • Treat when clinical disease (+clinical pathology) and/or