貓白血病於 台灣盛行率之調查與藥物組合(類固醇與人類合成干擾素α)於此病毒誘發免疫性溶血性貧血貓治療效果之評估

Abstract

貓白血病毒 (Feline leukemia virus, FeLV)及貓免疫缺陷病毒 (feline immunodeficiency virus, FIV)皆為造成貓隻疾病之反轉錄病毒。其中FeLV較具有致病性，亦較其他種病原更容易發展出多樣性的臨床呈像。為了解台灣地區貓反轉錄病毒在不同生活型態貓中的感染率，本研究首先調查2005至2006年FeLV，發現在流浪貓及家貓感染率分別為3% (5/161)及1.6% (3/188)，而FIV則分別為14% (23/161)及7.9% (15/188)。其中43隻感染FeLV的貓隻發生率最高的相關疾病為貧血 (26/43, 60.5%)、其次為腫瘤 (16/43, 37.2%)。而26隻出現貧血的患貓中，有17隻 (17/26, 65.4%)罹患免疫性溶血性貧血，顯示在貓白血病相關之貧血疾病中，免疫性溶血性貧血也可能是造成貧血的原因之一。為評估合併使用類固醇及人類和成干擾素治療FeLV誘發免疫性溶血性貧血之成效，本研究收集17隻年齡中位數為3歲 (0.8-7歲)之貓白血病p27 Ag陽性、同時發生自體凝集或球狀紅血球增多症診斷為免疫性溶血性貧血之患貓，將其分成兩組。其中10隻貓合併使用類固醇 (0.5-8 mg/kg/day)和人類重組干擾素 (2.5x105-1x106 IU/kg, SC SID-Q2D)治療為group 1，另外7隻貓單獨使用類固醇 (0.5-2 mg/kg/day)治療為group 2。Group 1貓隻於第14天時之血紅素與血容比均顯著高於group 2，治療組的存活時間亦顯著長於控制組 (p<0.05)。治療組中最長存活期為大於1600天。本研究中13隻長期使用類固醇控制貓白血病相關免疫性溶血性貧血之患貓中， 10隻貓出現高血糖，其中6隻貓更出現需以胰島素控制之糖尿病及2隻患貓發生角膜病變。總結，台灣地區貓白血病及貓愛滋病之盛行率在流浪貓約為家貓之兩倍。本研究為首篇針對貓白血病誘發免疫性溶血性貧血患貓合併使用人類重組干擾素α與類固醇治療之研究。結果顯示治療組在血液學檢查結果及存活期都顯著優於控制組，除了長時間使用高劑量類固醇所造成的高血糖、糖尿病與角膜病變之外，並未出現與人類重組干擾素-α相關之副作用。本研究結果提供臨床上貓白血病相關免疫性溶血性貧血時一個新的治療選擇。

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with global impact on the health of domestic cats. This study was conducted to determine prevalence of strayed and client-owned cats for retrovirus infection in Taiwan by examination of FIV antibodies or FeLV antigen. Immune mediated anemia and tumor are the most common diseases caused by FeLV in this study. 17 cats, the medium of age was 3 years old (range from 0.8 to 7 years), were confirmed with feline leukemia virus infection and diagnosed with immune mediated hemolytic anemia (IMHA) by autoagglutination and spherocytosis. We separated them into two groups. Group 1 (n=10) was treated with a combination of prednisolone (range: 0.5-8 mg/kg) orally per day and injected subcutaneously with human interferon-α-2a (Roferon-AR, range: 2.5x105-1x106IU/kg) every days initially and reduced the frequency after remission of anemia. Group 2 (n=7) was treated with prednisolone orally (range: 0.5-2 mg/kg) per day only. Since then RBC and PCV are both statistic significant higher in group 1 than group 2 in the 14th day of treatment. Moreover, the survival time of group 1 is significantly longer than group 2. The longest survival time in group 1 is 1600 days (still alive). 10 (10/13) cats developed hyperglycemia after long-term prednisolone administration (>30 days), in which, 6 (6/13) cats developed steroid-induced diabetes mellitus and were controlled under insulin injection thereafter. 2 (2/13) cats developed keratopathy bullae as well. In conclusion, prevalence of retrovirus infection is higher in strayed cats than in client-owned cats in Taiwan. The combination of prednisolone and interferon-α showed an effective therapeutic strategy in control of FeLV induced IMHA anemic patients. Although hyperglycemia, diabetes mellitus and keratopathy bullae appeared during the treatment, it’s still provided a good alternative choice in treating FeLV induced IMHA.