婴儿利什曼原虫感染的异质性：利用皮肤寄生虫负荷来识别高传染性犬只。
Heterogeneities in Leishmania infantum infection: using skin parasite burdens to identify highly infectious dogs.
作者信息
Courtenay Orin, Carson Connor, Calvo-Bado Leo, Garcez Lourdes M, Quinnell Rupert J
机构信息
School of Life Sciences, and Warwick Infectious Disease Epidemiology Research (WIDER), University of Warwick, Coventry, United Kingdom.
Laboratório de Epidemiologia e Imunologia aplicada às Leishmanioses, Seção de Parasitologia, Instituto Evandro Chagas, Belém, Pará, Brazil ; Centro do Ciências Biológicas e da Saúde, Universidade do Estado do Pará, Belém, Pará, Brazil.
出版信息
PLoS Negl Trop Dis. 2014 Jan 9;8(1):e2583. doi: 10.1371/journal.pntd.0002583. eCollection 2014.
BACKGROUND
The relationships between heterogeneities in host infection and infectiousness (transmission to arthropod vectors) can provide important insights for disease management. Here, we quantify heterogeneities in Leishmania infantum parasite numbers in reservoir and non-reservoir host populations, and relate this to their infectiousness during natural infection. Tissue parasite number was evaluated as a potential surrogate marker of host transmission potential.
METHODS
Parasite numbers were measured by qPCR in bone marrow and ear skin biopsies of 82 dogs and 34 crab-eating foxes collected during a longitudinal study in Amazon Brazil, for which previous data was available on infectiousness (by xenodiagnosis) and severity of infection.
RESULTS
Parasite numbers were highly aggregated both between samples and between individuals. In dogs, total parasite abundance and relative numbers in ear skin compared to bone marrow increased with the duration and severity of infection. Infectiousness to the sandfly vector was associated with high parasite numbers; parasite number in skin was the best predictor of being infectious. Crab-eating foxes, which typically present asymptomatic infection and are non-infectious, had parasite numbers comparable to those of non-infectious dogs.
CONCLUSIONS
Skin parasite number provides an indirect marker of infectiousness, and could allow targeted control particularly of highly infectious dogs.
背景
宿主感染异质性与传染性（向节肢动物媒介传播）之间的关系可为疾病管理提供重要见解。在此，我们量化了婴儿利什曼原虫在储存宿主和非储存宿主种群中的寄生虫数量异质性，并将其与自然感染期间的传染性相关联。组织寄生虫数量被评估为宿主传播潜力的潜在替代标志物。
方法
在巴西亚马逊地区的一项纵向研究中，通过qPCR对82只狗和34只食蟹狐的骨髓和耳部皮肤活检样本中的寄生虫数量进行了测量，此前已有关于传染性（通过异种接种诊断）和感染严重程度的数据。
结果
寄生虫数量在样本间和个体间高度聚集。在狗中，与骨髓相比，耳部皮肤中的总寄生虫丰度和相对数量随感染持续时间和严重程度增加。对白蛉媒介的传染性与高寄生虫数量相关；皮肤中的寄生虫数量是传染性的最佳预测指标。通常表现为无症状感染且无传染性的食蟹狐，其寄生虫数量与无传染性的狗相当。
结论
皮肤寄生虫数量提供了传染性的间接标志物，并可实现对高传染性狗的针对性控制。
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