Putra I Gusti Agung Arta, Adi Anak Agung Ayu Mirah, Astawa I Nyoman Mantik, Kardena I Made, Wandia I Nengah, Soma I Gede, Brotcorne Fany, Fuentes Agustin
Laboratory of Animal Anatomy and Physiology, Faculty of Animal Husbandry, Udayana University, Kampus Bukit, Jimbaran, Badung, Bali, Indonesia.
Primate Research Center, Udayana University, Kampus Bukit, Jimbaran, Badung, Bali, Indonesia.
Vet World. 2022 May;15(5):1341-1346. doi: 10.14202/vetworld.2022.1341-1346. Epub 2022 May 27.
Japanese encephalitis (JE) is a zoonotic infectious inflammatory brain disease caused by the JE virus (JEV). Considerable research into the seroprevalence of JE in domestic animals has been conducted, but there have been no reports of its occurrence in wild animals, including long-tailed macaques (). This study aimed to estimate the seroprevalence of JEV infection and its determinants in long-tailed macaques in Bali and the prevalence of mosquito vectors.
Blood samples (3 mL) were collected from a population of (92 heads) inhabiting a small forest with irrigated rice field nearby (wetland area) in Ubud, Gianyar, and from two populations in dryland areas with no wet rice field (Uluwatu, Badung, and Nusa Penida, Bali Province, Indonesia). The collected sera were tested for antibodies against JEV using a commercially available enzyme-linked immunosorbent assay kit (qualitative monkey JE Immunoglobulin G antibody kit). The seropositivity of the antibodies was then compared based on different variables, namely, habitat type, age, and sex.
The seroprevalence of the JEV antibodies in all the samples tested was found to be 41.3%. The seropositivity of the monkey serum samples collected from the wetland area was 46.4%, which was higher than the seropositivity of the sera samples collected from the dried field areas (1.25%). Monkey sera collected from the wetland areas were 6.1 times (odds ratio [OR]: 6.1; 95% confidence interval [CI]: 0.71-51.5, p>0.05) more likely to be seropositive compared to the monkey sera collected from the dried field areas. Meanwhile, female monkeys were 1.79 times (OR: 1.79; 95% CI: 0.76-4.21; p>0.05) more likely to be seropositive to JEV than males. Similarly, juvenile monkeys were 2.38 times (OR: 2.38; 95% CI: 0.98-5.79); p>0.05) more likely to be seropositive against the JEV than adult monkeys. However, none of these differences achieved statistical significance. Regarding the JEV mosquito vector collection, more mosquitoes were found in the samples from the wetland areas than from the dried field areas.
The study confirms the existence of JEV infection in long-tailed macaques in Bali. There were patterned seropositivity differences based on habitat, age, and sex of the monkeys, but these were not significant. The possibility of monkeys as a JEV reservoir and the presence of the mosquitoes as the JEV vector are suggested but require more study to confirm.
日本脑炎（JE）是一种由日本脑炎病毒（JEV）引起的人畜共患传染性脑部炎症疾病。针对家畜中JE血清阳性率已开展了大量研究，但尚无关于包括长尾猕猴在内的野生动物感染JE的报道。本研究旨在评估巴厘岛长尾猕猴中JEV感染的血清阳性率及其决定因素，以及蚊媒的流行情况。
从居住在 Gianyar 乌布德附近一片有灌溉稻田的小森林（湿地地区）的一群（92 只）长尾猕猴中采集 3 mL 血液样本，并从印度尼西亚巴厘省无水田的旱地地区的两个种群（乌鲁瓦图、巴东和努沙佩尼达）采集样本。使用市售酶联免疫吸附测定试剂盒（定性猴 JE 免疫球蛋白 G 抗体试剂盒）检测采集的血清中抗 JEV 的抗体。然后根据不同变量，即栖息地类型、年龄和性别，比较抗体的血清阳性率。
在所有检测样本中，JEV 抗体的血清阳性率为 41.3%。从湿地地区采集的猴血清样本的血清阳性率为 46.4%，高于从旱地地区采集的血清样本的血清阳性率（1.25%）。与从旱地地区采集的猴血清相比，从湿地地区采集的猴血清呈血清阳性的可能性高 6.1 倍（优势比[OR]：6.1；95%置信区间[CI]：0.71 - 51.5，p>0.05）。同时，雌性猴子感染 JEV 呈血清阳性的可能性比雄性高 1.79 倍（OR：1.79；95%CI：0.76 - 4.21；p>0.05）。同样，幼年猴子感染 JEV 呈血清阳性的可能性比成年猴子高 2.38 倍（OR：2.38；95%CI：0.98 - 5.79；p>0.05）。然而，这些差异均未达到统计学显著性。关于 JEV 蚊媒采集，在湿地地区样本中发现的蚊子比旱地地区样本中的多。
该研究证实巴厘岛的长尾猕猴中存在 JEV 感染。基于猴子的栖息地、年龄和性别存在血清阳性率差异模式，但不显著。提示猴子可能是 JEV 的宿主，蚊子可能是 JEV 的传播媒介，但需要更多研究来证实。
