Xishan Biology

Introduction to Pathogens

Rotavirus

Rotavirus (RV), belonging to the family Reoviridae and the genus Rotavirus, was first identified in 1973 by Australian researchers led by Bishop, who discovered it in ultrathin sections of biopsies from children suffering from acute gastroenteritis. This virus is the primary pathogen responsible for viral diarrhea in humans, as well as in mammals and birds. Studies have shown that globally, rotavirus infections lead to approximately 23 million outpatient visits and 2.3 million hospitalizations each year. Moreover, rotavirus can also cause gastroenteritis in numerous animal species, including common farm animals (cattle, pigs, sheep), exotic animals (camels, giraffes), non-human primates (macaques), domestic pets (dogs, cats), rodents, and birds.

So, what exactly are the characteristics of rotavirus? The following article will explore this in detail.

Pathology

 

Rotavirus is a double-stranded RNA virus, and its structure along with the proteins it encodes are illustrated in the figure below. The rotavirus exhibits an icosahedral shape measuring 65–75 nm in length under electron microscopy. The genome enclosed within the inner capsid of the rotavirus consists of 11 RNA segments, ranging in size from 660 bp to 3,300 bp. Each segment encodes one of six structural proteins: VP1–VP4, VP6, and VP7, which collectively form the three-layered architecture of the rotavirus capsid. Specifically, the outermost layer is composed of VP4 and VP7, the middle layer is made up of VP6 protein, and the innermost layer is formed by VP2 protein. For the viral particle to remain infectious, it must retain the complete three-layered capsid structure.

Epidemiology

 

Rotavirus is primarily transmitted via the fecal-oral or oral-oral route, but it can also spread through water sources or be transmitted via respiratory droplets in aerosol form. Moreover, the virus is highly stable in the environment, exhibiting remarkable resilience and rarely succumbing to natural extinction. Rotavirus also displays exceptional cellular susceptibility and tropism, as it can only infect intestinal epithelial cells located at the tips of small intestinal villi within the host organism—thereby disrupting the normal physiological functions of these cells. After infection, the virus typically has an incubation period of 1 to 3 days. In some cases, individuals may remain asymptomatic or experience only mild symptoms; however, in more severe instances, the infection can lead to acute diarrhea, dehydration, electrolyte imbalances, and a range of other complex pathological manifestations.

The Impact on Research

 

The World Health Organization recommends that the best way to prevent rotavirus infection is through vaccination—with vaccines like RotaTeq™, Rotarix™, and Rotavac being the most commonly available live-attenuated vaccines on the market today. While Rotarix™ and RotaTeq™ are highly effective tools for protecting against rotavirus, several significant challenges still remain. First, the safety and efficacy of these vaccines have not been thoroughly studied in immunocompromised patients, raising concerns about potential adverse reactions. Second, in developed countries, the high cost of these vaccines limits public acceptance and accessibility. Third, ensuring sustainable vaccine supply for the general population through effective financial strategies remains a critical issue to address. Moreover, given the widespread nature of rotavirus infections, even improvements in sanitation cannot fully curb the virus's transmission among susceptible individuals and animals. Thus, prevention continues to be the cornerstone of current strategies against this virus. In this context, developing efficient methods for diagnosing rotavirus becomes absolutely essential. The most commonly used diagnostic approaches for rotavirus are outlined in the table below:

Diagnostic methods

Application Features

Immuno-electron microscopy techniques

When using this method, viral particles are prone to degradation in the external environment, which can compromise the accuracy of diagnosis. Additionally, electron microscopy equipment is relatively expensive and not widely available at the grassroots level, severely limiting the application of this technology.

Cell Culture Method

This method requires in vitro cultivation of the virus from samples, but only Group A rotavirus can be successfully cultured. Additionally, viral isolation is time-consuming and labor-intensive, and the detection sensitivity remains relatively low.

Enzyme-linked immunosorbent assay

This method is relatively easy to perform in the laboratory, low in cost, and offers high detection sensitivity as well as excellent specificity. However, the technique lacks specificity, making it unable to distinguish between the various subtypes of rotavirus. Additionally, enzyme-linked immunosorbent assays require a lengthy testing process and demand sophisticated laboratory conditions, making them less suitable for emergency situations or when handling small numbers of samples.

PCR Technology

This technology features rapidity, high sensitivity, and strong specificity, and it doesn’t require complex or expensive instrumentation. It allows for electrophoretic and sequencing-based identification of purified PCR products.

Real-time fluorescence quantitative PCR technology

This method boasts high reaction sensitivity and enables real-time monitoring, allowing for quantitative analysis of the product. Moreover, multiplex fluorescent quantitative PCR offers high throughput, ensuring rapid and time-saving results—making it particularly advantageous for simultaneously handling multiple samples in clinical diagnostics.

With the continuous innovation of experimental methods and technologies, prevention and diagnosis of rotavirus are also rapidly advancing. This, in turn, presents new challenges for laboratory animal facilities and professionals. Readers and friends are welcome to continue sharing your valuable experiences and suggestions.

References

 

1. Patton JT. Rotavirus diversity and evolution in the post-vaccine world. Discov Med. 2012 Jan;13(68):85-97. PMCID: PMC3738915; PMID: 22284787.

2. Xu Yao. Establishment of a Multiplex Q-PCR Assay for Genotyping Group A Rotaviruses [D]. South China University of Technology, 2013.

3. Desselberger U, Iturriza-Gómara M, Gray JJ. Rotavirus epidemiology and surveillance. Novartis Found Symp. 2001;238:125-47; discussion 147-52. doi: 10.1002/0470846534.ch9. PMID: 11444024.

 

Table of Contents