ABSTRACT
BACKGROUND Dogs are the main peridomiciliary reservoir of Leishmania infantum thus the correct diagnosis of infection is essential for the control of the transmission and treatment as well. However, the diagnosis is based on serological assays that are not fully effective. OBJECTIVE We aimed to establish an effective serological assay for the diagnosis of L. infantum infected dogs using Leishmania-derived recombinant antigens. METHODS Leishmania derived rK39-, rK28-, rKR95-based enzyme-linked immunosorbent assay (ELISA) was standardized using symptomatic and asymptomatic L. infantum-infected dogs. Then 2,530 samples from inquiry in endemic areas for VL were evaluated and the results compared with recommended assays by the Brazilian Ministry of Health (MH algorithm). Further samples from a cohort of 30 dogs were searched. FINDINGS For rK39-, rK28- and rKR95-ELISA the sensitivity was around 97% and specificity 100%. The positivity of these three ELISA in the inquiry samples was 27-28%, around 10% higher than the assays currently in use. When cohort samples were searched, we observed likely false-negative results (> 65%) with supposedly negative samples that turned positive six months later with the assays in use (MH algorithm). MAIN CONCLUSIONS For the diagnosis of L. infantum-infected dogs, rK39-based ELISA showed better diagnostic performance than other assays in use in Brazil and worldwide.
Subject(s)
Animals , Dogs , Enzyme-Linked Immunosorbent Assay/standards , Enzyme-Linked Immunosorbent Assay/veterinary , Antibodies, Protozoan/blood , Leishmania infantum/immunology , Dog Diseases/diagnosis , Leishmaniasis, Visceral/diagnosis , Recombinant Proteins/immunology , Brazil , Enzyme-Linked Immunosorbent Assay/methods , Serologic Tests , Sensitivity and Specificity , Leishmania infantum/isolation & purification , Leishmaniasis, Visceral/blood , Leishmaniasis, Visceral/veterinary , Antigens, Protozoan/biosynthesisABSTRACT
The rodents Proechimys guyannensis have led a great interest because they are considered as hosts to several pathogens causing zoological diseases. Therefore, it is important to know their biological and physiological parameters. The age at first cubs delivery and the average of birth interval per female were evaluated. The estimated age at puberty was 83 days. The number of pups born per delivery did not differ significantly when associated with the female mating age. However, an increase in the average mortality rate correlated with the increase in delivery number per female was detected. There is no statistical difference neither in the litter size in different seasons of the year, nor in the body weight between sexes for all ages. Differences were found in the daily water consumption and in the feed intake in animals with approximately 100 days of age, perhaps owing to the increased need for energy intake due to sexual activity or even because they had not reached adult weight yet. The parameters assessed in the present study are of relevance for maintaining this species in captivity as a laboratory animal.
Roedores da espécie Proechimys guyannensis têm motivado grande interesse por serem frequentementeconsiderados como hospedeiros de diversos agentes patogênicos causadores de doenças. É importanteestabelecer seus parâmetros biológicos e fisiológicos; neste contexto, foram avaliadas a idade ao primeiroparto e a média de intervalo de natalidade por fêmea. A idade à puberdade foi estimada em 83 dias.O número de filhotes nascidos por parto não diferiu significativamente com a idade das fêmeas aoacasalarem. Observou-se aumento da taxa média de mortalidade de acordo com o aumento do númerode partos por fêmea. Não houve diferença estatística no tamanho da ninhada em diferentes estações doano; tampouco houve diferença de peso entre os sexos. Foram detectadas diferenças no consumo diáriode água e no consumo de ração em animais com menos e mais de 100 dias de idade, talvez em funçãode aumento da necessidade de consumo de energia pela atividade sexual ou mesmo por ainda não teremalcançado o peso corporal de adulto. Os parâmetros apresentados são relevantes para a futura manutençãodesta espécie em cativeiro como animal de laboratório.
Subject(s)
Animals , Animals, Laboratory , RodentiaABSTRACT
A ocorrência de dirofilariose pulmonar humana relaciona-se com a prevalência de infecção por Dirofilaria immitis na população canina. Várias espécies de mosquitos são vetores desse nematóide. Analisaram-se amostras de sangue canino coletados nas vilas Pingo d'Agua e União, município de Salvaterra (Ilha do Marajó, PA), em junho, 2004 (n=34) e abril, 2005 (N=90). Os diagnósticos parasitológico e imunológico (ELISA - kit SNAP® 3DX, Biobrasil) foram comparados (chi2, alfa=0,05) no exame de 34 amostras. A prevalência na população (N=90) foi avaliada pelo ELISA. O ELISA revelou mais positivos (25/34; 73,5 por cento) que a gota espessa (23/34, 67,6 por cento) e o Knott (21/34, 61,8 por cento), mas a diferença não foi significativa (p>0,05). A freqüência de infecção por D. immitis na faixa de 0 a 2 anos foi 58 por cento, enquanto em cães mais velhos foi 100 por cento. A prevalência da dirofilariose canina em Pingo d'Agua e Vila União foi alta (53,5 por cento), indicando risco de transmissão do parasito às pessoas nessa área.
The occurrence of human pulmonary dirofilariasis maintains a relation with the prevalence of Dirofilaria immitis infection in the canine population. Several mosquito species are vectors of this nematode. Canine blood samples collected in Pingo d'Agua and União villages, Salvaterra municipality (Marajó Island, Pará), in June, 2004 (n=34) and April, 2005 (N=90) were analyzed. Parasitological and immunological (ELISA - kit SNAP® 3DX, Biobrasil) diagnoses were compared following the examination of 34 samples. The prevalence in the population (N=90) was evaluated by means of ELISA. ELISA revealed more positive samples (25/34; 73.5 percent) than thick smears (23/34, 67.6 percent) or Knott (21/34, 61.8 percent), but the differences were not significant (p>0.05). The frequency of D. immitis infection was 58 percent in dogs ranging from 0-2 years old, whereas in older dogs it was 100 percent. The prevalence of canine dirofilariasis was high in Pingo d'Agua and Vila União (53.5 percent), indicating the risk of parasite transmission to the people in this area.