Vokaty S, McPherson V O, Camus E, Applewhaite L
Inter-American Institute for Cooperation on Agriculture, Georgetown, Guyana.
Rev Elev Med Vet Pays Trop. 1993;46(1-2):57-9.
The objective of this study was to determine the seroprevalence rates of Trypanosoma vivax and Trypanosoma evansi in sheep in coastal Guyana. Blood samples were taken from a systematic random sample of one hundred and ninety-three (193) sheep on twenty-two (22) farms in Region 5, Mahaica/Berbice, a coastal area of Guyana. Age, breed, sex, and farm of origin were recorded for all sampled sheep. One hundred and seventy-six (176) serum samples were submitted for Indirect Fluorescent Antibody (IFA) testing for T. vivax and T. evansi. Fluorescence was graded as 0 (negative), 1+(very weak), 2+(weak), 3+(strong) or 4+(very strong), measured at 1:160 dilution of serum. Samples were considered to be sero-positive if any fluorescence was observed. Indirect Fluorescent Antibody results were received for one hundred and sixty-one (161) samples. One hundred and three (64%) sera were sero-positive for Trypanosoma sp. Of these, 38 (23.6%) sera were positive to T. evansi only, 11 (6.8%) were positive to T. vivax only and 54 (33.5%) were positive for both. As cross reactions occur between T. vivax and T. evansi, it was difficult to determine the true species of exposure for the sera which tested positive to both species. The overall sero-prevalence rate of 64% suggests that trypanosomosis is endemic in sheep in coastal Guyana. This was the first serological evidence of T. evansi in Guyana. Although T. vivax is believed to be pathogenic in sheep, the clinical significance of T. evansi remains unknown. The vector of both species of trypanosomes in sheep on the north coast of South America also is not known.
本研究的目的是确定圭亚那沿海地区绵羊中活跃锥虫和伊氏锥虫的血清阳性率。从圭亚那沿海地区马海卡/伯比斯第5区的22个农场中，对193只绵羊进行系统随机抽样采集血样。记录了所有采样绵羊的年龄、品种、性别和原产农场。将176份血清样本送去进行活跃锥虫和伊氏锥虫的间接荧光抗体（IFA）检测。荧光强度分为0（阴性）、1+（非常弱）、2+（弱）、3+（强）或4+（非常强），在血清1:160稀释度下测量。如果观察到任何荧光，则样本被视为血清阳性。收到了161份样本的间接荧光抗体检测结果。103份（64%）血清对锥虫属呈血清阳性。其中，38份（23.6%）血清仅对伊氏锥虫呈阳性，11份（6.8%）仅对活跃锥虫呈阳性，54份（33.5%）对两者均呈阳性。由于活跃锥虫和伊氏锥虫之间会发生交叉反应，因此很难确定对两种锥虫均呈阳性的血清的真正感染种类。总体血清阳性率为64%，这表明锥虫病在圭亚那沿海地区的绵羊中呈地方流行。这是圭亚那伊氏锥虫的首个血清学证据。虽然活跃锥虫被认为对绵羊具有致病性，但伊氏锥虫的临床意义仍不清楚。南美北海岸绵羊体内这两种锥虫的传播媒介也未知。
