尼泊尔部分地区内脏利什曼病传播的调查。
Investigation of Visceral LeishmaniasisTransmission in Selected Districts of Nepal.
机构信息
Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu.
Department of Microbiology and Immunology, McGill University, Montreal, Canada.
出版信息
J Nepal Health Res Counc. 2022 Jun 2;20(1):194-201. doi: 10.33314/jnhrc.v20i01.4161.
BACKGROUND
Visceral leishmaniasis is transmitted to humans by Leishmania donovani infected Phlebotomus argentipes sandflies. Nepal has successfully met the elimination target of less than 1 case per 10,000, although recently this threshold has been surpassed demonstrating ongoing transmission. The main objective of the present study was to investigate transmission of visceral leishmaniasis in 4 visceral leishmaniasis endemic districts of Nepal including Palpa, Morang, Saptari and Sarlahi.
METHODS
Human blood samples (331), domestic animals blood samples [goats (n =67), dogs (n =1), cows (n = 6), buffaloes (n = 16), and ox (n = 10)] and sandflies samples (3976 from 142 households) were collected from the villages of these 4 districts. Human blood samples were tested for VL antibodies using the rK39 rapid diagnostic test (InBios International, Seattle, WA). kDNA of L.donovani was amplified by PCR from DNA extracted from human blood, animal blood and sandfly samples.
RESULTS
Out of 331 screened across 4 districts,32 were positive on rK39 serology and 16 were positive by PCR amplification of kDNA from L. donovani. The majority of the positive serology and PCR tests were from the Ishworpur village in the Sarlahi district where there was an outbreak of 18 cases of VL. This study also revealed the presence of L. donovani DNA in female P. argentipes sandflies collected from the Ishworpur village of Sarlahi, 6 villages in the Saptari,10 villages in the Palpa, and from 9 villages in the Morang. Blood samples from domestic animals in the same villages were negative for kDNA detection by PCR.
CONCLUSIONS
The results of human and sandfly findings strongly point towards local transmission of visceral leishmaniasis in these 4 districts of Nepal. Notably, there is a significant level of transmission in the Ishworpur village in the Sarlahi district. The observations from this study suggest that domestic animals are not a reservoir host for L. donovani in these districts in Nepal. Ongoing surveillance is needed to identify new outbreaks such as in the Sarlahi district.
背景
内脏利什曼病由感染白蛉的利什曼原虫引起，通过白蛉传播给人类。尼泊尔已成功达到每 10,000 人少于 1 例的消除目标，尽管最近这一门槛已经被超过，表明仍在继续传播。本研究的主要目的是在尼泊尔的 4 个内脏利什曼病流行地区（包括帕尔帕、莫朗、萨塔里和萨拉希）调查内脏利什曼病的传播情况。
方法
从这 4 个地区的村庄采集了 331 份人血样本、67 份山羊血样本、1 份狗血样本、6 份牛血样本、16 份水牛血样本、10 份公牛血样本和 3976 份白蛉样本。用人血 rK39 快速诊断检测试剂盒（西雅图 InBios 国际公司）检测人血样本的 VL 抗体。从人血、动物血和白蛉样本中提取 DNA，用 PCR 扩增 L.donovani 的 kDNA。
结果
在 4 个地区筛查的 331 份样本中，32 份 rK39 血清学阳性，16 份 PCR 扩增 kDNA 阳性。大多数阳性血清学和 PCR 检测结果来自萨拉希地区的 Ishworpur 村，那里暴发了 18 例内脏利什曼病。这项研究还表明，在萨拉希的 Ishworpur 村、萨塔里的 6 个村庄、帕尔帕的 10 个村庄和莫朗的 9 个村庄采集的雌性白蛉中存在 L. donovani DNA。来自同一村庄的家畜血液样本经 PCR 检测 kDNA 均为阴性。
结论
人类和白蛉样本的结果强烈表明，尼泊尔这 4 个地区存在内脏利什曼病的本地传播。值得注意的是，萨拉希地区的 Ishworpur 村存在明显的传播水平。本研究的观察结果表明，在尼泊尔的这些地区，家畜不是 L. donovani 的储存宿主。需要进行持续监测，以发现新的暴发，如萨拉希地区。
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