Rotavirus infection in the tropics : Toward a better understanding of the viral ecology and application to preventive strategies

不管一个人住在哪里，一个人在5岁之前至少会感染一次轮状病毒。这种感染造成了毁灭性的影响，估计有60万儿童死亡，其中大多数在发展中国家。目前已有两种第二代轮状病毒疫苗，并在100多个国家获得许可。轮状病毒颗粒上有两种中和抗原VP7和VP4，它们都被认为在介导对轮状病毒感染的免疫中起重要作用。因此，监测循环轮状病毒基因型对引入轮状病毒疫苗至关重要。从全球通过疫苗接种控制轮状病毒腹泻的角度来看，了解轮状病毒基因型在发展中国家的分布非常重要，尤其要关注一种新兴基因型。这项研究表明，在尼泊尔加德满都儿童身上发现的轮状病毒中，G12基因型的检出率异常高，为20-49%。为了方便快速地检测这种新兴的基因型，我们成功地开发了一种针对G12轮状病毒的RT-PCR基因分型方法，并表明该方法对野生型菌株有效。尼泊尔G12菌株电泳型的多样性及其与P[8]、P[6]和P[4]等多种P型的相关性表明，这些以前不常见的G12菌株在尼泊尔存在了一段时间，不太可能是短暂的，需要进一步和持续的监测。

Irrespective of where one lives, one gets at least one rotavirus infection by the time one becomes 5 years of age. The infection causes devastating effects of an estimated 600,000 deaths in children mostly in developing countries. Two second-generation rotavirus vaccines are now available and licensed in more than 100 countries. There are two neutralization antigens, VP7 and VP4, on rotavirus particles and both are believed to be important in mediating immunity against rotavirus infection. Thus, surveillance of circulating rotavirus genotypes is essential in introducing rotavirus vaccines. From the perspective of global control of rotavirus diarrhea by vaccination, it is important to know the distribution of rotavirus genotypes in developing countries with special attention to an emerging genotype. This study showed unusually high detection rates, 20-49%, of G12 genotypes among rotaviruses recovered from children in Kathmandu, Nepal. To allow an easy and rapid detection of this emerging genotype, we have successfully developed an RT-PCR genotyping for G12 rotaviruses, and showed that the method worked well for wild type strains. The observed diversity in electropherotypes of G12 strains in Nepal and its association with various P types including P[8], P[6], and P[4] suggest that such previously unusual G12 strains were there in Nepal for a certain period of time and unlikely to be transient, warranting a further and continued surveillance.