Sporothrix brasiliensis infecting cats in northeastern Brazil: New emerging areas in Paraíba state

ABSTRACT: Sporotrichosis is a subcutaneous mycosis caused by fungus of the Sporothrix complex, and in Brazil the main species reported is Sporothrix brasiliensis, of which the diseased cat is the transmitter. Although, its occurrence has increased in the state of Paraíba, Brazil, since 2016, data on the disease in this state are limited. Therefore, this research aimed to identify molecularly isolates of Sporothrix spp. from domestic cats from cities in Paraíba, and in this way to expand the understanding of the disease in the state. Thirty-nine samples were analyzed, obtained from skin lesions of domestic felines, from the following cities in Paraíba: João Pessoa, Pilões, Patos, Areia, Bananeiras and Guarabira. Cytological analysis was performed to screen the samples, followed by fungal culture, and the molecular characterization of the isolates was performed, using the species-specific Polymerase Chain Reaction (PCR) or partial sequencing of the calmodulin gene. All isolates were identified as S. brasiliensis. The sequencing showed 100% similarity to the S. brasiliensis CBS 120339 strain. In view of this, it is concluded that in the study areas the species involved in cases of feline sporotrichosis is S. brasiliensis, its presence in Paraíba demonstrated the spread of the agent in regions distant from the epicenters in Brazil, alerting to the possible occurrence of zoonotic outbreaks similar to those found in the South and Southeast regions of the country. In addition, it highlights the emerging role of felines in the transmission of sporotrichosis in new endemic areas of Brazil.摘要：孢子丝菌病是由孢子丝菌复合群（Sporothrix complex）真菌引发的皮下真菌病，在巴西，报道的主要致病菌为巴西孢子丝菌（Sporothrix brasiliensis），其主要传播媒介为患病家猫。尽管自2016年以来巴西帕拉伊巴州的孢子丝菌病病例数有所上升，但该州相关研究数据仍较为匮乏。为此，本研究旨在对帕拉伊巴州不同城市家猫分离的孢子丝菌属（Sporothrix spp.）菌株进行分子鉴定，以深化对该州此病流行情况的认知。本研究共分析39份采自帕拉伊巴州若昂佩索阿、皮洛内斯、帕托斯、阿雷亚、巴纳内拉斯及瓜拉比拉等城市家猫皮肤病变部位的样本。研究先通过细胞学分析对样本进行初筛，随后开展真菌培养，再采用物种特异性聚合酶链反应（Polymerase Chain Reaction，PCR）或钙调蛋白基因（calmodulin gene）部分测序技术对分离菌株进行分子鉴定。所有分离菌株均被鉴定为巴西孢子丝菌。测序结果显示，这些菌株与巴西孢子丝菌CBS 120339标准株的同源性达100%。综上，本研究区域内引发家猫孢子丝菌病的病原菌为巴西孢子丝菌；该菌在帕拉伊巴州的检出，表明此病原菌已扩散至巴西本土远离疫情核心区的区域，提示该国南部与东南部地区曾出现的人兽共患病暴发疫情或在其他区域重演，需引起警惕。此外，本研究凸显了家猫在巴西新发孢子丝菌病流行区域的传播媒介作用。