Agbonlahor D E, Erah A, Agba I M, Oviasogie F E, Ehiaghe A F, Wankasi M, Eremwanarue O A, Ehiaghe I J, Ogbu E C, Iyen R I, Abbey S, Tatfeng M Y, Uhunmwangho J
Lahor Research Laboratories and Medical Centre, Benin City, Edo State; Department of Medical Laboratory Science, College of Health Sciences, Niger Delta University, Amassoma, Bayelsa State, Nigeria.
Department of Medical Laboratory Science, Igbinedion University, Okada, Nigeria.
J Vector Borne Dis. 2017 Apr-Jun;54(2):146-150.
BACKGROUND & OBJECTIVES: Lassa fever has been endemic in Nigeria since 1969. The rodent Mastomys natalensis has been widely claimed to be the reservoir host of the Lassa virus. This study was designed to investigate the dis- tribution of species of rodents in three states (Edo, Delta and Bayelsa) of Nigeria and to determine the prevalence of Lassa virus amongst trapped rodents in the selected states.
Rodents were trapped during November 2015 to October 2016 from the three states in South-South re- gion of Nigeria. Total RNA was extracted from the blood collected from the trapped rodents. Reverse transcription polymerase chain reaction (RT-PCR) was used to confirm the presence of Lassa virus in the rodents.
The results revealed that six species of rodents were predominantly present in these geographical locations. Mus musculus (39.4%) had the highest prevalence, closely followed by Rattus rattus (36.1%), R. fuscipus (20.3%), M. natalensis (2%), Myosoricinae soricidae (1.2%) and R. norvegicus (1%). The overall positivity (carrier rate) of Lassa virus was 1.6% amongst the 1500 rodents caught in the three states. In Edo and Delta States, the RT-PCR results showed presence of Lassa virus in R. rattus, M. musculus and M. natalensis. On the other hand, only M. na- talensis was detected with the virus, amongst the species of rodents caught in Bayelsa State. M. natalensis recorded the highest Lassa virus among rodents trapped in Edo (87%), Delta (50%) and Bayelsa (11%) States respectively.
INTERPRETATION & CONCLUSION: The rather low Lassa virus positive among rodents in Bayelsa State of Nigeria may explain the absence of reports of outbreak of Lassa fever over the past 48 yr in the state. The results also confirmed that apart from Mastomys natalensis, other rodents such as Rattus rattus and Mus musculus may also serve as res- ervoirs for Lassa virus. From the findings of this cross-sectional study, it was concluded that a more comprehensive study on rodents as reservoir host, need to be undertaken across the entire states of Nigeria, for better understanding of the epidemiology and endemicity of Lassa fever.
自1969年以来，拉沙热在尼日利亚一直呈地方性流行。大家鼠（Mastomys natalensis）被广泛认为是拉沙病毒的储存宿主。本研究旨在调查尼日利亚三个州（埃多、三角州和巴耶尔萨）啮齿动物的种类分布，并确定在选定州捕获的啮齿动物中拉沙病毒的流行情况。
于2015年11月至2016年10月期间，在尼日利亚南部地区的三个州捕获啮齿动物。从捕获的啮齿动物采集的血液中提取总RNA。采用逆转录聚合酶链反应（RT-PCR）确认啮齿动物中拉沙病毒的存在。
结果显示，这些地理位置主要有六种啮齿动物。小家鼠（Mus musculus，占39.4%）的患病率最高，紧随其后的是黑家鼠（Rattus rattus，占36.1%）、棕黑家鼠（R. fuscipus，占20.3%）、大家鼠（M. natalensis，占2%）、非洲水鼩鼱（Myosoricinae soricidae，占1.2%）和褐家鼠（R. norvegicus，占1%）。在这三个州捕获的1500只啮齿动物中，拉沙病毒的总体阳性率（携带率）为1.6%。在埃多州和三角州，RT-PCR结果显示黑家鼠、小家鼠和大家鼠中存在拉沙病毒。另一方面，在巴耶尔萨州捕获的啮齿动物种类中，仅在大家鼠中检测到该病毒。大家鼠在埃多州（87%）、三角州（50%）和巴耶尔萨州（11%）捕获的啮齿动物中拉沙病毒检出率最高。
尼日利亚巴耶尔萨州啮齿动物中拉沙病毒阳性率较低，这可能解释了该州在过去48年中没有拉沙热疫情报告的原因。结果还证实，除大家鼠外，其他啮齿动物如黑家鼠和小家鼠也可能是拉沙病毒的储存宿主。根据这项横断面研究的结果，得出结论，需要在尼日利亚的所有州对作为储存宿主的啮齿动物进行更全面的研究，以便更好地了解拉沙热的流行病学和地方性流行情况。
