Prevalence and incidence of canine visceral leishmaniasis and its clinical-immunological features in an endemic area of the Brazilian Amazon

Liliane A Carneiro; Luciana V Lima; Marliane B Campos; Thiago Vasconcelos Dos Santos; Patrícia K Ramos; Márcia D Laurenti; Fernando T Silveira

doi:10.1002/vms3.1218

Prevalence and incidence of canine visceral leishmaniasis and its clinical-immunological features in an endemic area of the Brazilian Amazon

Vet Med Sci. 2023 Nov;9(6):2463-2474. doi: 10.1002/vms3.1218. Epub 2023 Aug 31.

Authors

Liliane A Carneiro¹, Luciana V Lima², Marliane B Campos², Thiago Vasconcelos Dos Santos², Patrícia K Ramos², Márcia D Laurenti³, Fernando T Silveira^{2

4}

Affiliations

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

Background: A 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/methods: Diagnosis 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.

Results: IFAT/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.

Conclusion: These results reinforce the need of adopting preventive strategies against CVL as early as in the first semester of the dog's life.

Keywords: Brazilian Amazon; canine visceral leishmaniasis; clinical-immunological features; incidence; prevalence.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Brazil / epidemiology
Cohort Studies
Dog Diseases* / diagnosis
Dogs
Humans
Incidence
Leishmaniasis, Visceral* / epidemiology
Leishmaniasis, Visceral* / veterinary
Prevalence