台灣宜蘭地區性動物收容中心犬隻鉤端螺旋體血清陽性率與雨量之關聯性

Abstract

本研究自臺灣宜蘭縣動物收容中心採樣，進行流浪犬隻鉤端螺旋體之血清抗體陽性率調查，使用顯微凝集測試 (Microscopic Aggulutination Test, MAT) 檢驗8種鉤端螺旋體血清型。採樣時間由2011年11月起至2013年4月止，共收集807個流浪犬隻血清樣本。陽性犬隻共174頭，犬隻陽性率為21.6 %，其中29頭 (16.7 %) 屬於一種以上血清型之多重感染。血清型陽性反應數218個，血清型陽性率為27.0 %，其中有57個 (26.1 %) 為急性感染。流浪犬隻鉤端螺旋體之血清型分布依序為Shermani 32.6 % (71 / 218)，Javanica 22.5 % (49 / 218)，Canicola 13.8 % (30 / 218)，Patoc 11.5 % (25 / 218)，Poi 7.8 % (17 / 218)，Icterohaemorrhagiae 4.1 % (9 / 218)，Pomona 4.1 % (9 / 218)，Kennewicki 3.7 % (8 / 218)。統計分析結果顯示，陽性率在性別之間無顯著性差異 (p = 0.265 > 0.05)，犬隻年齡在二月齡以上顯著地高於二月齡以下 (p = 0.018 < 0.05)；二月齡以上公犬顯著地高於二月齡以下公犬及母犬 (p = 0.003 < 0.05, p = 0.025 < 0.05)。8種鉤端螺旋體血清型中，Javanica與Pomona的陽性率在公犬顯著地高於母犬 (p = 0.037 < 0.05, p = 0.011 < 0.05)。而血清型Canicola與Javanica的陽性率在二月齡以上犬隻顯著地高於二月齡以下 (p = 0.0011 < 0.05, p = 0.0002 < 0.05)。僅有血清型Shermani的急性感染率顯著地高於慢性 (p = 0.002 < 0.05)，而且佔總體急性感染的46.7 %。犬隻鉤端螺旋體急性感染率與3個月前的兩個月累積雨量有顯著地高度相關 (r = 0.62, p < 0.05)；由此結果，監控兩個月的累積雨量可預警鉤端螺旋體感染的發生。根據過去的研究及本研究，血清型Shermani在調查中具有最高的血清型分布與急性感染比例，因此台灣地區使用的犬隻鉤端螺旋體疫苗應優先納入血清型Shermani。

A sero-epidemiological study on canine leptospirosis was conducted in stray dogs from a regional animal shelter of Yilan, Taiwan. The microscopic agglutination test (MAT) was used to screen for leptospirosis using 8 serovars. 807 sera of stray dogs were collected from November 2011 to April 2013. Of a total of 807 serum samples tested, 174 (21.6 %) dogs with 218 (27 %) reactions were seropositive for Leptospira agglutinins, 29 (3.6 %) dogs with 73 (33.5 %) reactions were multiple-infected and 57 (7.1 %) reactions within 45 (5.6 %) dogs had current infections. The distributions of leptospiral serovars were Shermani 32.6 % (71 / 218), Javanica 22.5 % (49 / 218), Canicola 13.8 % (30 / 218), Patoc 11.5 % (25 / 218), Poi 7.8 % (17 / 218), Icterohaemorrhagiae 4.1 % (9 / 218), Pomona 4.1 % (9 / 218) and Kennewicki 3.7 % (8 / 218). The prevalence of stray dogs was not significantly different between male and female, but it’s significantly different between age older and young than two months (p < 0.05, χ2). The acute infectious rate of serovar Shermani was significantly higher than chronic (p < 0.05, χ2) and its proportion was 46.7 % of all acute infections, it was considered the distribution of this serovar was on the increase. There was less leptospiral infectious risk for individual dog living in closed environment, on the contrary, a crowd of dog living in closed environment had more infectious risk. A statistically significant correlation (r = 0.62, p < 0.05) was noted between the monthly acute infectious rate of leptospirosis and the two months cumulative rainfall recorded 3-months prior to diagnosis, and rainfall could be used to predict the occurrence of leptospirosis. According to this and past researches, serovar Shermani was the most dominated in seropositive reactions and acute infections, therefore, it should be a top priority for inclusion in the vaccine used locally in Taiwan.