Primates Manegement Section, National Center of Primates (Secretary of Health and Environment Surveillance, Ministry of Health), Pará State, Ananindeua, Pará, Brazil.
Parasitology Department, Evandro Chagas Institute (Secretary of Health and Environment Surveillance, Ministry of Health), Ananindeua, Pará, Brazil.
Vet Med Sci. 2023 Nov;9(6):2463-2474. doi: 10.1002/vms3.1218. Epub 2023 Aug 31.
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.
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.
These results reinforce the need of adopting preventive strategies against CVL as early as in the first semester of the dog's life.
一项为期 2 年的队列研究分析了巴西帕拉州内脏利什曼病流行地区 316 只杂种犬中犬利什曼原虫（L.）chagasi 感染的流行率、发病率和临床免疫学特征。
目的/方法：在研究开始时和 6、12 和 24 个月时，通过间接荧光抗体试验（IFAT-IgG）、利什曼素皮肤试验（LST）和寄生虫搜索（从腘淋巴结抽吸）对感染进行诊断。
IFAT/LST 显示感染有三种免疫谱：（I）IFAT/LST（81），（II）IFAT/LST（17）和（III）IFAT/LST（13）。谱 I、II 和 III 的患病率分别为 25.6%、5.4%和 4.1%，总患病率为 35.1%。谱 I、II 和 III 的发病率分别为 5.4%、0.3%和 0.0%，每月每只狗的总发病率为 5.7%。<1 岁、≥1 岁、<7 岁和≥7 岁的年龄范围的发病率在<1 岁的年龄范围最高（每月每只狗 6.6%）。在患病率（85.7%谱 I）时，19%的犬呈寄生虫学阳性，在发病率（100%谱 I）时为 11%。179 只感染犬的临床症状显示 145 只（81%）为谱 I（82%亚临床）；21 只（11.7%）为谱 II（100%亚临床）；13 只（7.3%）为谱 III（84.6%亚临床）。谱 I（40.2%）向患病犬的转变高于谱 II（5.8%）和谱 III（9%）（p<0.05）。免疫转变表明，只有 3.2%的谱 I 犬（患病率）转为 LST（其中 2 只在第一个 6 个月结束时，1 只在第 24 个月结束时），而 82.3%的谱 II 犬转为 IFAT（11 只在第一个 6 个月，3 只在 12 个月后）。仅谱 I 犬的死亡率为 100%。
这些结果强调了尽早在犬生命的第一个学期采取预防策略来预防 CVL 的必要性。
