Leprosy mailing list – December 20^th, 2005

Ccn:     all.

From:   J Shen, Nanjing, Jiangsu, People’s Democratic Republic of China.

---

 

 

 

 

Dear Dr Noto,

I was very interested in reading the article "On the origin of leprosy" which was published on Sciences (13 May 2005, p 1040).  The following is my opinion after reading the article.

 

The article “On the origin of leprosy” (Sciences, 13 May 2005, p 1040) is very interesting to every leprologist. The authors reported that leprosy seemed to originate from eastern Africa or the near East and to spread with human migration at the evidences of genetic comparison of the Mycobacterium leprae.

 

However, to my understanding of this article, I am not fully convinced by the findings that said the eastern Africa and near East were the origin of leprosy.  The key problem is that there were too few clinical and laboratory specimens collected in eastern Africa, the possible origin of leprosy.  In Ethiopia only collected 2 clinical or laboratory specimens.  If collected more specimen, M. leprae with other single-nucleotide polymorphism (SNP*) types, such as SNP type 1 predominated in India might be detected.

 

The same problem also existed in France and Morocco, there were only 2 specimens collected.

 

The inference of leprosy spread into North America and America through Europe is only convinced at the evidence of more specimens.

I am not fully convinced that there is enough evidence to favour India was not the “cradle” of leprosy.  M. Leprae with SNP type 1 could spread a long distance from India to Madagascar and Malawi, how it could infer that East Africa is the origin of leprosy with only 2 clinical or laboratory specimens?

 

The study is meaningful in explaining the origin of leprosy.  I hope to test more clinical or laboratory specimens, and then get a convincible answer.

 

Kind regards,

 

Shen Jianping

 

Dr Jianping SHEN,
Institute of Dermatology,
Chinese Academy of Medical Sciences,
National Centre for STD and Leprosy Control,
12 Jiangwangmiao Road,
Nanjing, Jiangsu,
People’s Democratic Republic of China 210042

 

 

* M leprae has 4 types of SNP detected by leprosy researchers so far.  SNP of M leprae has a characteristic of distribution in areas due to mutation induced by environmental situation.