Affiliation:
1. Primates Manegement Section National Center of Primates (Secretary of Health and Environment Surveillance, Ministry of Health), Pará State Ananindeua Pará Brazil
2. Parasitology Department, Evandro Chagas Institute (Secretary of Health and Environment Surveillance, Ministry of Health) Ananindeua Pará Brazil
3. Pathology Department, Medical School of São Paulo University, São Paulo São Paulo Brazil
4. Postgraduate Program in Tropical Diseases, Tropical Medicine Nucleus Federal University of Pará Belém Pará Brazil
Abstract
AbstractBackgroundA cohort study for 2 years period analysed the prevalence, incidence and clinical–immunological features of canine Leishmania (L.) chagasi‐infection in 316 mongrel dogs in a visceral leishmaniasis‐endemic area in Pará State, Brazil.Objective/MethodsDiagnosis of infection was performed by the indirect fluorescent antibody test (IFAT‐IgG), the leishmanin skin test (LST) and a parasite search (from the popliteal lymph node aspiration) at the beginning of the study and at 6, 12 and 24 months intervals.ResultsIFAT/LST revealed three immune profiles of infection: (I) IFAT(+)/LST(−) (81), (II) IFAT(−)/LST(+) (17) and (III) IFAT(+)/LST(+) (13). Prevalence of profiles I, II and III were 25.6, 5.4 and 4.1%, and an overall prevalence 35.1%. Incidence of profiles I, II and III were 5.4, 0.3 and 0.0%, and an overall incidence 5.7% dogs per month. Incidence at the age ranges <1 year, ≥1 year, <7 years and ≥7 years evidenced a highest rate in the age range <1 year (6.6% dogs per month). Parasitological diagnosis was positive in 19% dogs at the prevalence (85.7% profile I), and in 11% at the incidence (100% profile I). The clinical picture of 179 infected dogs showed 145 (81%) of profile I (82% subclinical); 21 (11.7%) of profile II (100% subclinical); and 13 (7.3%) of profile III (84.6% subclinical). Conversion from subclinical to sick dogs was higher (p < 0.05) in profile I (40.2%) than in profiles II (5.8%) and III (9%). Immunological conversion showed that only 3.2% of profile I dogs (prevalence) converted to LST(+) (two at the end of the first 6 months and 1 after 24 months), while 82.3% of profile II dogs converted to IFAT(+) (11 in the first 6 months, whereas three after 12 months). A 100% death rate was observed in dogs from profile I alone.ConclusionThese results reinforce the need of adopting preventive strategies against CVL as early as in the first semester of the dog's life.
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