Calf Rotavirus Research Articles

Rotavirus A associated pathology of intestine and mesenteric lymph nodes and occurrence in bovine calves of Gwalior and Bareilly regions

To understand the pathology of natural cases of rotavirus (RVA) in bovine calves, a total of 40 cases below 6 months died due to diarrhoea were studied, out of which 7 cases (17.5%) turned positive for RVA by RT-PCR. Histopathology of small intestine showed loss of villous enterocytes, blunting and fusion of villi, elongation of crypts and mononuclear cells infiltration in the lamina-propria. The mesenteric lymph nodes were severely depleted of lymphocytes. These changes were corroborated with presence of RVA antigen in sections by dFAT and nucleic acid by RT-PCR. The fluorescent signals were more in mesenteric lymph nodes than in intestine. Besides, 115 rectal fecal samples were also collected from calves for RVA detection by RT-PCR using VP6 gene specific sets of primers. Dead carcasses of calves (n= 40) belonged to organized dairy farm of Bareilly, while rectal fecal samples belonged to both organized (n= 38) and unorganized farms (n= 77) of Bareilly and Gwalior. The overall occurrence of RVA was 19.3% (30/155), comprising 5/37 cases (13.5%) from Gwalior (MP) and 25/118 cases (21.1%) from Bareilly (UP). These findings suggest the infection of RVA widely prevalent in calves and have potential to escape from the intestinal site to mesenteric lymph nodes.

ADAPTATION OF HUMAN ROTAVIRUS STRAINS OF GROUP A TO THE REPRODUCTION IN PASSAGED CELL CULTURES.

The incidence of rotavirus gastroenteritis in the world still has no tendency to reduction. The development of an effective vaccine would reduce or, in the future, even defeat this highly contagious dangerous disease. However, both in Russia and abroad there is still no developed technique for adapting and cultivating strains of the human rotavirus A that would stably produce a high "yield" of virus progeny in transplanted culture cells. The phenomenon of gene exchange for the segmented genome of rotavirus was used by foreign researchers to create the rotavirus vaccine using reassortant strains which are the result of joint cultivation of low-titer (1-2·106 virions per ml) human rotavirus strains and rotavirus strains of animals, such as monkey rotavirus SA-11 or Nebraska calf rotavirus diarrhea providing a relatively high "yield" of virus progeny (1·107-1·108). It is clear that such vaccine compositions will not be able to replace a full-fledged vaccine of human rotavirus strains of different serotypes, but they can be used for the time being as a solution to the problem. Ideally, a rotavirus vaccine is needed that includes the full set of G and P serotypes of rotaviruses circulating in the territory of their application. The paper describes an original technique for adaptation and cultivation of human rotaviruses of group A on the culture of transplantable cells developed by the authors. This technique allows 5·108 virions to be obtained per 1 ml of culture fluid. High-titer cultivated strains of human rotavirus that can be used as vaccine strains were obtained, as well as highly-active antigens for the construction of diagnostic test-systems.

Genotyping of Rotavirus in Neonatal Calves with Acute Gastroenteritis in Iraq

Globally, Rotavirus is the common major etiologic agents of diarrhea in infant, young children and neonatal calves. It is very important to early diagnose the disease for effective treatment. The objective of this study was to determine the prevalence, molecular characteristics, and the effect of rotavirus strains for severe gastroenteritis in neonatal calves in five Iraqi governorates (Al-Qadissiya, Babel, Kerbala, Missan, Wassit). A total of 125-stool specimens were examined, it have been collected from calves form the period between November 2015 to March 2016. The ages were ranging from 6 to 60 weeks. The specimens were examined using Chromatographic Immunoassay, enzyme-linked immunosorbent assay (ELISA) and Polymerase-chain reaction (PCR). Our results gave us 67 (53.6%) positive by chromatographic immunoassay, 45 (36%) positive by ELISA and 32 (25.6%) positive by PCR. Genotyping were analyzed by multiplex PCR. Genotype combination G1P[8] was (30%) followed by G1P[4] (20%), G3P[4] (20%), G2P[4] (10%), G2P[8] (10%) and G9P[4] (10%). Such information will not only aid in seeking advocacy for introducing rotavirus vaccine in national immunization program in Iraq, but will also help in the evaluation of the efficacy of these vaccines in relation to the rotavirus genotyping circulation.

Comparative Prevalence and Molecular Characterization of Group A Rotavirus in Cow Calves of Punjab, India

Comparative Prevalence and Molecular Characterization of Group A Rotavirus in Cow Calves of Punjab, India

Egg yolk IgY antibodies: A therapeutic intervention against group A rotavirus in calves

Bovine group A rotavirus (RVA) is considered the major cause of diarrhea in intensively reared neonatal calves. Chicken egg yolk antibodies (IgY) are efficient in protecting neonatal calves from RVA diarrhea; however, the value of this intervention in calves once diarrhea has appeared is unclear. The aim of the present study was to evaluate the application of RVA-specific IgY as a passive treatment in those cases. The experimental groups were: G1=RVA-specific IgY treatment; G2=no Ab treatment; and G3=colostrum deprived+no Ab treatment. IgY treatment significantly reduced virus shedding, diarrhea duration and severity compared to G2 and G3 calves. However, it caused a partial suppression of systemic Ab responses to RVA that could be associated with less severe diarrhea. The oral treatment with IgY for 7days was associated with significantly higher antibody secreting cell responses in the calves compared with other groups of animals.

Detection of bovine rotavirus in diarrheic calves by using rapid test in some Mid-Euphrates provinces

The study was aimed to determine the Rotavirus infection rates in diarrheic calves and effectiveness of some epidemiological factors on that rate in some provinces in Mid–Euphrates region in Iraq (Babylon, Al-Najaf, Karbala, Al-Qadisyia provinces). A total of 530 calves aged between 1-60 day were examined and fifty fecal (50) samples were collected from diarrheic calves only within six months period from November-2012 to April -2013. The fecal samples were examined for the presence of rotavirus by rapid rotavirus test (screening test), as well as the clinical examination for these diarrheic calves were done. The rapid test demonstrated that the rotavirus infection rate was 18/50 (36%). A 45.4% of rotavirus infection was found in calves less than 30 days of age which was significantly higher than 28.5% calves (30-60) days old. Male and female (37.5%, 40% respectively) were seen infected without any significant differences. The main clinical signs observed on rotavirus diarrheic calves were include, watery voluminous diarrhea with profound weakness and mild depression, so as temperature, respiration, heart rates could be decreased and appetite was changeable towards loss or anorectic. In Babylon, the highest rotavirus infection rate was recorded at 60%, and fewer rates in Karbala 20% and 40%, 33% in AL-Najaf and AL-Qadisyia provinces respectively. The rotavirus infection rate in diarrheic calves was affected by months significantly, which it was higher at January 75%, so as in November 50%, December 40% and February 33.3%, but not recorded in March and April.

Pathogenicity characterization of a bovine triple reassortant rotavirus in calves and piglets

Rotaviruses are important human and animal pathogens with high impact on public health and livestock industry. There is little evidence about the cross-species pathogenicity and extra-intestinal infections of animal and human reassortant rotaviruses, particularly based on all 11 genotyping data. In this study, the bovine triple reassortant KJ56-1 strain harboring two bovine-like genome segments, eight porcine-like genome segments, and one human-like genome segment was used to evaluate the cross-species pathogenicity in its parent species, calves and piglets, and to determine its abilities of causing viremia and extra-intestinal tropisms in piglets. The KJ56-1 strain isolated from a calf diarrhea fecal sample replicated without causing diarrhea and severe intestinal pathology in calves. However, piglets inoculated with this strain showed persistent severe diarrhea and marked intestinal pathology. By SYBR Green real-time RT-PCR, viral RNA was detected in the sera, mesenteric lymph node, lung, liver, choroid plexus, and cerebrospinal fluid in the experimental piglets. An immunofluorescence assay confirmed viral replication in these extra-intestinal organs and tissues. These results indicated that the bovine triple reassortant KJ56-1 strain was virulent to piglets but not to calves. Our data also demonstrated that the reassortant rotaviruses had the ability to spread to the bloodstream from the gut, enter and amplify in the mesenteric lymph node, and disseminate to the extra-intestinal organs and tissues.

Intestinal and extra-intestinal pathogenicity of a bovine reassortant rotavirus in calves and piglets

Despite the impact of bovine group A rotaviruses (GARVs) as economically important and zoonotic pathogens, there is a scarcity of data on cross-species pathogenicity and extra-intestinal spread of bovine reassortant GARVs. During the course of characterizing the genotypes of all 11 genomic segments of bovine GARVs isolated from diarrheic calves in South Korea, a unique G6P[7] reassortant GARV strain (KJ9-1) was isolated. The strain harbors five bovine-like gene segments (VP7: G6; VP6: I2; VP1: R2; VP3: M2; NSP2: N2, and NSP4: E2), five porcine-like gene segments (VP4: P[7]; NSP1: A1; NSP3: T1, and NSP5: H1), and one human-like gene segment (VP2: C2). To investigate if this reassortant strain possessed cross-species pathogenicity in calves and piglets, and could induce viremia and extra-intestinal spread in calves, colostrum-deprived calves and piglets were experimentally inoculated with the KJ9-1 strain. The KJ9-1 strain caused severe diarrhea in experimentally infected calves with extensive intestinal villous atrophy, but replicated without causing clinical symptoms in experimentally infected piglets. By SYBR Green real-time RT-PCR, viral RNA was detected in sera of the calves at post-inoculation day (PID) 1, reaching a peak at PID3, and then rapidly decreasing from PID4. In addition, viral RNA was detected in the mesenteric lymph node, lungs, liver, choroid plexus, and cerebrospinal fluid. An immunofluorescence assay confirmed viral replication in the extra-intestinal organs and tissues of virus-inoculated calves. The data indicates that the homologous/heterologous origin of the NSP4 gene segment (E2 genotype), may play a key role in the ability to cause diarrhea in calves and piglets.

Determination of G and P type diversity of group A rotaviruses in faecal samples of diarrhoeic calves in Kashmir, India

To determine the genetic diversity of group A rotaviruses in bovine calves in Kashmir, India. Of 200 diarrhoeic faecal samples collected from calves, aged between 0 and 6 months and screened by polyacrylamide gel electrophoresis (PAGE), 31 were detected positive for group A rotaviruses. On G and P genotyping by reverse transcriptase-polymerase chain reaction (RT-PCR), G10P[11] turned out to be predominant (80·64%) combination followed by G8P[11] (7·7%). One (3·84%) sample carried mixed infection of G8+G10P[11]. Two (7·7%) samples belonged to P[11] genotype, but their G genotype specificity could not be established. This study revealed the ambiguity in RT-PCR typing method. All the samples that turned out to be G10 by Isegawa et al. (1993; Mol Cell Probes7, 277) primers could be amplified by G3 specific primers of Gouvea et al. (1990; J Clin Microbiol32, 1338). However, on homology study of their VP7 gene sequence, the strains turned out to be G10. Rotavirus is prevalent in diarrhoeic calves in Kashmir, India, and G10P[11] is the predominant genotype in circulation. There is evidence of mixed infection. Even though RT-PCR method is the quick way to type the strains, there is need to generate more sequence data to improve the specificity of typing primers. Rotavirus is a significant cause of diarrhoea in calves. RT-PCR typing method needs to be supported by the sequence data, and there is need to re-evaluate the primers used for typing.

Comparison of electrocardiographic parameters and serum electrolytes and microelements between single infection of rotavirus and coronavirus and concurrent infection of Cryptosporidium parvum with rotavirus and coronavirus in diarrheic dairy calves.

To study the effects of concurrent infection of Cryptosporidium parvum with rotavirus and coronavirus in comparison to single infection of rotavirus and coronavirus, electrocardiographic parameters and serum electrolytes and microelements are compared between eight calves with concurrent infection and ten calves with single infection. Calves with single infections had higher serum concentrations of sodium and calcium, and less potassium, copper, and iron, which was not statistically significant. They also had significantly shorter P and QRS wave amplitudes and longer T wave duration in electrocardiogram patterns.

Comparative efficacy of immunological, molecular and culture assays for detection of group A rotavirus from faecal samples of buffalo (Bubalus bubalis) calves

Group A rotaviruses play an important role in causing gastroenteritis and mortality in buffalo (Bubalus bubalis) calves. A number of assays like RNA-polyacrylamide gel electrophoresis (RNA-PAGE), enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR) and virus isolation have been employed for rotavirus diagnosis. We evaluated the comparative efficacy of different assays for detection of group A rotavirus in buffalo calves. A total of 455 faecal samples collected from five organized farms in northern India were screened by monoclonal antibody based ELISA, 33 (7.25%) samples were positive for group A rotavirus. The percent positivity ranged from 3.22% to 28% in different organized farms. The same samples were also tested by RNA-PAGE, which revealed classical 11 segments with 4:2:3:2 migration patterns in 14 faecal samples showing 3.08% positivity. Virus isolation was successfully done from 21 (4.61%) samples. However, only 15 (3.3%) samples yielded a specific product of 864 and 1,011 bp for VP4 and VP7 genes, respectively, by RT-PCR. The sensitivity and specificity of ELISA, RNA-PAGE and RT-PCR was 100%, 66.67% and 71.43% and 97%, 100% and 100%, respectively, considering virus isolation as standard test. ELISA being simple, fast and sensitive assay can be used as routine laboratory test for the diagnosis of group A rotavirus and field epidemiological studies.

Evaluation of relationship between Rotavirus and Coronavirus infections with calf diarrhea by capture ELISA.

Rotavirus and Coronavirus are two main causes of severe diarrhea in human infants and many animal species worldwide. Calves up to 3 months old can be affected by these viruses. The importance of these viruses in cattle industry is due to substantial economic loss, treatment costs, and reduced growth rates in beef and dairy calves. Mixed infections caused by Rotavirus and Coronavirus can lead to severe form of diarrhea. In present case-control study, 261 samples of healthy and diarrheic calves from farms around Mashhad were collected. These samples were tested by antigen-capture enzyme-linked immunosorbent assay (Bio-X diagnosis kit). The results showed that the prevalence of Rotavirus and Coronavirus infection in diarrheic calves is 26.98% and 3.17%, respectively. Also, there was no significant relationship between infection with Rotavirus, Coronavirus, and diarrhea in the studied population.

Frequency of group A rotavirus in diarrhoeic calves in Brazilian cattle herds, 1998–2002

The frequency of group A bovine rotavirus (gpA BRV) in calves from 1998 to 2002 was determined by the polyacrylamide gel electrophoresis technique in 2177 faecal samples, of which 1898 samples were diarrhoeic and 279 were of normal consistency (control group) that were collected from asymptomatic calves for comparative purposes. The animals were from beef and dairy cattle herds (n = 321) from 158 counties in seven States (Paraná, São Paulo, Minas Gerais, Mato Grosso do Sul, Mato Grosso, Goiás and Rondônia) and four Brazilian geographical regions (south, south-east, centre-west, and north). GpA BRV was detected in 19.4% (369/1898; p = 0.0001) of the samples collected in calves with diarrhoea and in only 2.2% (6/279; p = 0.0001) of the faeces with normal consistency. The proportion of positive samples collected from beef and dairy cattle herds was 22.8% (205/899; p = 0.0001) and 16.4% (169/999; p = 0.0005), respectively. In relation to age, a higher prevalence of infections was found in calves up to 30 days old, where 33.0% (189/573; p = 0.0001) and 20.2% (138/683; p = 0.0001) of the diarrhoeic faecal samples from beef and dairy cattle herds, respectively, were positive for gpA BRV. These results show the possible importance of inclusion of gpA BRV in the management of neonatal calf diarrhoea in Brazilian cattle herds.

Simultaneous Serodetection of 10 Highly Prevalent Mouse Infectious Pathogens in a Single Reaction by Multiplex Analysis

Under current practices of mouse colony maintenance, sera from mice are analyzed for antibodies against several widespread infectious pathogens by conventional immunoassays, generally enzyme-linked immunosorbent assay (ELISA). To test for multiple agents, these methods consume large volumes of mouse serum and are laborious and time-consuming. More efficient immunoassays, using small amounts of sample, are therefore needed. Accordingly, we have developed a novel multiplex diagnostic system that employs fluorescent microbeads, coated with purified antigens, for simultaneous serodetection of 10 mouse infectious agents. Individually identifiable, fluorescent microbeads were coated with antigens from Sendai virus, mouse hepatitis virus, Theiler's mouse encephalomyelitis virus/GDVII strain, mouse minute virus, mouse cytomegalovirus, respiratory enteric orphan virus (Reo-3 virus), mouse parvovirus, calf rotavirus for epizootic diarrhea virus of infant mice, vaccinia virus for ectromelia virus, and Mycoplasma pulmonis. Standard sera, singly positive for antibodies to individual infectious agents, were generated by inoculation of BALB/cj and C57BL/6j mice. Sera from these experimentally infected mice, as well as sera from naturally infected mice, were analyzed using a mixture of microbeads coated with antigens of the 10 infectious agents listed above. Results demonstrated that the multiplex assay was at least as sensitive and specific as ELISA for serodetection. Importantly, the multiplex assay required only 1 microliter of serum for simultaneous serodetection of the 10 mouse infectious agents in one reaction vessel. Thus, this multiplex microbead assay is a reliable, efficient, and cost-effective diagnostic modality that will impact serosurveillance of mice used in research.

The dsRNA Electrophoretype of Some Isolated Iranian Calf Rotaviruses

Summary A rapid and simple technique for diagnosis of rotaviral diarrhea is polyacrylamide gel electrophoresis (PAGE) of dsRNA extracted from fecal samples. To determine the electrophoretype of Iranian calf rotavirus, 23 rotaviral positive fecal samples from diarrheic Holstein calves at the age of less than one month in Tehran region were examined. The viral dsRNA was extracted with phenol-chloroform, and analyzed by PAGE and silver staining. According to PAGE all of the electrophoretypes were identified as long genome electrophoretypes, characteristic of animal group A rotavirus. There was not any unusual segment rearrangement.

Modulation by colostrum-acquired maternal antibodies of systemic and mucosal antibody responses to rotavirus in calves experimentally challenged with bovine rotavirus.

The effect of colostral maternal antibodies (Abs), acquired via colostrum, on passive protection and development of systemic and mucosal immune responses against rotavirus was evaluated in neonatal calves. Colostrum-deprived (CD) calves, or calves receiving one dose of pooled control colostrum (CC) or immune colostrum (IC), containing an IgG1 titer to bovine rotavirus (BRV) of 1:16,384 or 1:262,144, respectively, were orally inoculated with 105.5 FFU of IND (P[5]G6) BRV at 2 days of age. Calves were monitored daily for diarrhea, virus shedding and anti-BRV Abs in feces by ELISA. Anti-rotavirus Ab titers in serum were evaluated weekly by isotype-specific ELISA and virus neutralization (VN). At 21 days post-inoculation (dpi), all animals were euthanized and the number of anti-BRV antibody secreting cells (ASC) in intestinal and systemic lymphoid tissues were evaluated by ELISPOT. After colostrum intake, IC calves had significantly higher IgG1 serum titers (GMT=28,526) than CC (GMT=1195) or CD calves (GMT<4). After BRV inoculation, all animals became infected with a mean duration of virus shedding between 6 and 10 days. However, IC calves had significantly fewer days of diarrhea (0.8 days) compared to CD and CC calves (11 and 7 days, respectively). In both groups receiving colostrum there was a delay in the onset of diarrhea and virus shedding associated with IgG1 in feces. In serum and feces, CD and CC calves had peak anti-BRV IgM titers at 7 dpi, but IgA and IgG1 responses were significantly lower in CC calves. Antibody titers detected in serum and feces were associated with circulation of ASC of the same isotype in blood. The IC calves had only an IgM response in feces. At 21 dpi, anti-BRV ASC responses were observed in all analyzed tissues of the three groups, except bone marrow. The intestine was the main site of ASC response against BRV and highest IgA ASC numbers. There was an inverse relationship between passive IgG1 titers and magnitude of ASC responses, with fewer IgG1 ASC in CC calves and significantly lower ASC numbers of all isotypes in IC calves. Thus, passive anti-BRV IgG1 negatively affects active immune responses in a dose-dependent manner. In ileal Peyer’s patches, IgM ASC predominated in calves receiving colostrum; IgG1 ASC predominated in CD calves. The presence in IC calves of IgG1 in feces in the absence of an IgG1 ASC response is consistent with the transfer of serum IgG1 back into the gut contributing to the protection of the intestinal mucosa.

Detection of human rotavirus in faeces from diarrhoeic calves in north-east Nigeria.

Information on the epidemiology of rotavirus in any particular area is necessary for vaccine development against the disease caused by the virus. This study presents preliminary information on the prevalence of human rotavirus in diarrhoeic calves in North-east Nigeria. Faecal samples from 188 diarrhoeic calves in various farms in North-east Nigeria, obtained between November 1998 and February 1999, were analysed by ELISA for the presence of rotaviruses. A prevalence rate of 3.2% was recorded, with the virus being prevalent among calves aged 29-56 days (p < 0.05). The implications of these findings are discussed with respect to the close association between the herdsmen and their animals and the sharing of a common source of drinking water in the predominantly livestock-producing communities of North-east Nigeria.

Evaluation of the ImmunoCardSTAT Rotavirus Assay For On-site Detection of Bovine Rotavirus

Diarrhea is the most important disease in neonatal dairy and beef calves. Significant economic loss occurs due to increased morbidity and mortality, treatment costs and reduced growth rates. Rotaviruses usually cause diarrhea during the first three weeks of life. Clinical signs can be quite variable and are similar to those caused by other neonatal bovine enteropathogens such as corona virus and Eschericia coli.&#x0D; Diagnosis of rotavirus in calves is based on the identification of viral particles, antigens or nucleic acids in feces. Tests include direct or immune electron microscopy, immunofluorescence, antigen capture enzyme- linked immunosorbant assay (ELISA), latex agglutination and polymerase chain reaction (RT-PCR). All of these tests are useful for diagnosing rotavirus infections, but in general are relegated to use by diagnostic laboratories. Development of an on-site diagnostic assay for bovine rota virus would be a useful tool for veterinarians and cattle producers in making management decisions regarding neonatal bovine diarrhea.&#x0D; The ImmunoCardSTAT Rotavirus (ICS-RV) Assay (Meridian Diagnostics, Cincinnati, OH) is a patient-side assay designed to detect group A rotavirus in humans. This assay is based upon rapid immunomigration (RIM) technology. This technology allows for packaging of all reagents into a single-step assay that can then be used patient-side (similar to a "home pregnancy test"). The objective of this study was to evaluate the ICS-RV assay's usefulness as an on-site diagnostic test for bovine rotavirus.

Genomic diversity and prevalence of Rotavirus in cow and buffalo calves in northern India.

Faecal samples were collected from seventy-eight diarrhoeic cow and buffalo calves between November 1998 and February 1999 to study the genomic diversity and prevalence of Rotavirus infection by ribonucleic acid polyacrylamide gel electrophoresis (RNA-PAGE) and enzyme-linked immunosorbent assay (ELISA). In the organised dairy farm (where daily production and health records were maintained), the overall prevalence of infection with Rotavirus, recorded by RNA-PAGE and ELISA, was 27.02% (10/37) in both cow and buffalo calves. In unorganised dairy herds (where no production or health records were maintained), RNA-PAGE and ELISA detected infection with Rotavirus in 26.8% (11/41) of cow and 19.5% (8/41) of buffalo calves. Five distinct electropherotypes were found to circulate in cow and buffalo calves. All were short electropherotypes except the single long electropherotype observed in a buffalo calf in an unorganised dairy herd. Some differences in RNA migration pattern were observed when these electropherotypes were compared with the neonatal calf diarrhoea virus strain of Rotavirus. Some electropherotypes were restricted to one farm while others were found in both organised and unorganised dairy herds and in both cow and buffalo calves.

Dual infection of gnotobiotic calves with bovine strains of group A and porcine-like group C rotaviruses influences pathogenesis of the group C rotavirus.

There is serological evidence that bovine group C rotaviruses exist in the United States, but there are no reports of their isolation. Ninety fecal samples from calves with diarrhea, 81 samples from adult cows with diarrhea (winter dysentery), and 20 fecal samples from healthy adult cows were tested for group C rotaviruses by polyacrylamide gel electrophoresis, immune electron microscopy, and reverse transcription-PCR (RT-PCR). Three samples from adult cow diarrhea cases were positive only by RT-PCR, and a group C rotavirus was isolated from a positive sample in monkey kidney (MA104) cells (WD534tc/C). Genetically and serologically, the WD534tc/C strain was more closely related to the Cowden porcine group C strain than to the Shintoku bovine strain. Because the original cow feces also contained a group A rotavirus (detected after passage in cell culture), we hypothesized that such dual-rotavirus infections might play a role in the pathogenesis and host adaptation of rotaviruses. Thus, we examined the pathogenesis of WD534tc/C alone or combined with virulent (IND/A) or attenuated (NCDV/A) bovine group A rotaviruses in gnotobiotic calves. WD534tc/C alone induced diarrhea without (or with limited) virus shedding in inoculated calves (n = 3). In contrast, all calves coinfected with WD534tc/C and IND/A (n = 2) developed diarrhea and shed both viruses, whereas calves coinfected with WD534tc/C and NCDV/A (n = 3) developed diarrhea but did not shed either virus. Infection with WD534tc/C or NCDV/A alone caused only mild villous atrophy (jejunum and/or ileum), whereas dual infection with both viruses induced lesions throughout the small intestine. Although IND/A alone caused villous atrophy, more-widespread small intestinal lesions occurred in calves coinfected with WD534tc/C and IND/A. In conclusion, coinfection of calves with group A rotaviruses enhanced fecal shedding of a bovine group C rotavirus and the extent of histopathological lesions in the small intestines. Thus, our findings suggest a potential novel hypothesis involving dual infections for the adaptation of heterologous rotaviruses to new host species.