边境牧羊犬遗传病——TNS（翻译 Chery Bomb）

HEREDITARY NEUTROPENIA (TNS)

遗传性嗜中性白血球减少症 (TNS)

翻译：Chery Bomb

Hereditary neutropenia (or trapped neutrophil syndrome TNS) is a more recently described disease in Border Collies. Inheritance patterns and percentage of affected pups in litters indicate　that TNS is inherited in a recessive manner (like CL) with both parents having to be carriers of the　disease to produce an affected pup.

Symptoms may be seen in puppies as young as 2 weeks or as old as 7 months of age. Affected puppies are usually smaller, have slower growth rates, and can appear to have a “ferret like” head and a poor hair coat. Some puppies are not obviously different until they become ill. Other symptoms of disease include lameness, inappetence, diarrhoea and a high temperature. . 

遗传性嗜中性白血球减少症（又称嗜中性白细胞困阻症, TNS) 是一种新近在边境牧羊犬中发现的疾病。遗传模式及同窝幼犬中患病者的比率表明TNS以隐性方式遗传（与蜡样质脂褐素沉积病一样），即亲代双方均为疾病携带者的情况下才能产生患犬。

2周至7月龄的犬均可能发病。患犬通常体积较小，发育迟缓，并可能有一种“雪貂式”的头部和极差的被毛。一些幼犬在发病前表现得完全正常。其他症状包括跛行、食欲不振、腹泻及高烧。

Xrays of limb bones may show reduced density and thin cortices and in some cases fractures in metaphyses. Sometimes pups become ill after their first vaccination. Both male and female puppies of any colour can be affected. TNS is a disease which ultimately causes a deficiency of the immune system, so symptoms can vary between pups. Affected animals are eventually euthanased on humane grounds.

对四肢骨骼的X光检测显示出骨量减少，皮质变薄，甚至干骺端碎裂。有时犬只会在首次接种疫苗后发病。任何性别、任何颜色的犬都可能得病。TNS是一种最终导致免疫系统缺乏的疾病，不同犬只的临床症状也不同。患犬最后将被人道毁灭。

Diagnosis of TNS requires three criteria. Firstly, the pups need to show clinical symptoms consistent with the TNS. Secondly, blood tests which confirm a low neutrophil count are suspicious of TNS but do not provide a diagnosis. Puppies will occasionally develop low neutrophil counts for other reasons, eg. viral or bacterial infections, and should not be condemned on this basis. The third criteria bone marrow biopsy will give accurate diagnosis. Pups with TNS have 
been found to have an increased “myeloid to erythroid ratio” in their bone marrow. This means there are more white blood cells precursors in the bone marrow than there should be hence the name “trapped neutrophil syndrome” (
neutrophils trapped in the bone marrow) was made. 

确诊TNS需要三个条件。首先，犬只必须具备与TNS相同的临床症状。其次，血液检测显示出低嗜中性白细胞数的犬只可能患有TNS，但无法作出诊断。犬的白细胞数偶尔会因为其他原因减少，如病毒或细菌感染，因此不能作为确诊依据。第三个条件：骨髓活组织检查将给出准确的诊断。检查发现，患有TNS的犬只骨髓中的干细胞比例偏高，这意味着骨髓中的白细胞母体多于正常水平，此病也因此被称为“嗜中性白细胞困阻症”（指嗜中性白细胞被困在骨髓中，无法进入血流）。

For pet owners it should be emphasised that: 需要对犬主强调的是：

1. Only a small number of TNS litters have been reported to date. This problem is often detected by breeders before sale of the litter.

1. 迄今为止，只有一小部分的新生幼犬被报道患有TNS。繁殖者通常能在售出幼犬之前发现此病。

2. Carrier puppies live perfectly normal, healthy and will never show any symptoms of TNS. However carrier animals should not be used in breeding programs.

2. 作为携带者的犬只可以正常、健康地生活，不会显示任何TNS的症状。然而携带者不适合应用于配种。