Infections of nervous necrosis virus in wild and cage-reared marine fish from South China Sea with unexpected wide host ranges

The concerns about the impact of the nervous necrosis virus (NNV) infections in wild fish have been raised. This paper presents the results of quarterly surveys of NNV in wild and cage-reared marine fish from South China Sea. Samples of 892 wild fish belonging to 69 species and 381 cage-reared fish belonging to 11 species were collected and were detected by seminested PCR and nested PCR. In the case of seminested PCR, the positive signal was detected in 3.0% and 3.1% samples of wild and cage-reared fish, respectively. However, by nested RT-PCR, the positive signal was observed in 42.3% and 63.0% samples of wild and cage-reared fish, respectively. If the fish species were considered, the positive signal was detected in 21.7% and 72.7% species of wild and cage-reared fish by seminested PCR assay, respectively. However, by nested RT-PCR, the positive signal was observed in 65.2% and 100% species of wild and cage-reared fish, respectively. The nucleotide sequences of the nested PCR products were determined. Phylogenetic tree showed that all the obtained viral isolates belonged to the red-spotted grouper nervous necrosis virus (RGNNV) genotype. Thirty-five species of the marine fish were the new hosts of NNV.

Prevalence and complete genome characterization of turkey picobirnaviruses

The "light turkey syndrome" (LTS), in which birds weigh less than their standard breed character at the marketing time, is believed to be a consequence of viral enteritis at an early age (3-5 weeks) from which the birds never fully recover. In a previously published study, we collected fecal pools from 2, 3, 5 and 8 week old turkey poults (80 pools from LTS farms and 40 from non-LTS farms) and examined them for the presence of astro-, rota-, reo-, and coronaviruses. To determine the presence of additional enteric viruses, we analyzed a fecal pool by Illumina sequencing and found picobirnavirus (PBV). Segments 1 and 2 of this virus shared 45.8%aa and 60.9-64.5%aa identity with genogroup I of human PBV, respectively. Primers based on RNA-dependent RNA polymerase and capsid genes were designed for detection and molecular characterization of PBVs in the 120 fecal pools described above. From LTS farms, 39 of 80 (48.8%) pools were PBV positive while 23 of 40 (57.5%) were positive from non-LTS farms. The phylogenetic analysis of 15 randomly selected strains divided them into four subgroups within genogroup I (subgroups 1A-D). Nine strains were in subgroup IA showing 69.9-76.4%nt identity with human PBV GI strainVS111 from the Netherlands. Strains in subgroup IB (n=2) had 91.4-91.7%nt identity with chicken PBV GI strain AVE 42v1 from Brazil. Two strains in subgroup IC had 72.3-74.2%nt identity with chicken PBV strain AVE 71v3 from Brazil. In subgroup ID, two strains showed 72.4-81.8%nt identity with chicken PBV GI strain AVE 57v2 from Brazil. Subgroup IC and ID were the most divergent. Five of the 15 strains were typed using capsid gene primers. They showed 32.6-33.4%nt and 39.5-41.3%aa identity with VS10 human PBV strain. These results indicate co-circulation of divergent strains of PBVs among Minnesota turkeys.

Viral etiologies of acute dehydrating gastroenteritis in pakistani children: confounding role of parechoviruses

Despite substantial interventions in the understanding and case management of acute gastroenteritis, diarrheal diseases are still responsible for a notable amount of childhood deaths. Although the rotavirus is known to cause a considerable burden of pediatric diarrheal cases, the roles of other viruses remain undefined for the Pakistani population. This study was based on tertiary care hospital surveillance, from January 2009 to December 2010, including the detection of rotavirus, norovirus, astrovirus, and human parechovirus in children under the age of five using serological or molecular assays. Rotavirus, human parechovirus, norovirus, and astrovirus were detected in 66%, 21%, 19.5%, and 8.5% subjects, respectively. Human parechovirus genotypes, determined through analysis of VP1 gene sequences, showed a great diversity among co-circulating strains. Eighty percent of hospitalized children had dual or multiple viral infections, while 98% parechovirus positive cases were co-infected with rotavirus. The remarkable diversity of viruses associated with the childhood diarrhea in Pakistan calls for large-scale epidemiological surveys, coupled with case control studies, to ascertain their role in clinical manifestations. In addition, these findings also highlight the need for the implementation of up-to-date health interventions, such as the inclusion of a rotavirus vaccine in routine immunization programs for the improvement of quality in child health care.

Presence of viruses in wild eels Anguilla anguilla L, from the Albufera Lake (Spain)

A virological analysis was conducted on wild eels from the Albufera Lake (Spain). A total of 179 individuals at different growth stages were collected in two different surveys (2004 and 2008). Presence of anguillid herpesvirus (AngHV-1), aquabirnavirus and betanodavirus was confirmed by PCR procedures in both surveys, although the number of detections was clearly higher in 2008 (83% of the eels analysed resulted positive for virus presence). AngHV-1 was the viral agent most frequently detected, followed by aquabirnaviruses. Betanodaviruses were detected by the first time in wild eels, and although the detections were only made by nested PCR, high percentage of positives were achieved. In addition, in 2008, seven aquabirnaviruses were isolated. Phylogenetic analysis performed using partial sequences of both genomic segments of aquabirnaviruses indicated that the seven isolates could be typed as WB (genogroup I) on the basis of segment A sequences, but when segment B was used six of them clustered with C1 strain (genogroup V) and one was typed as Ab (genogroup II). These results indicate natural reassortment between different strains of aquabirnaviruses in the eels. Although betanodaviruses were not isolated in cell culture, the analysis of the sequence of the nested PCR product indicated that they clustered with SJNNV genotype. The diversity of viral agents and the high level of viral detections suggest that viral infections may play a more prominent role in the decline of the European eel than initially thought.

Population-based incidence of severe acute respiratory virus infections among children aged <5 years in rural Bangladesh, June-October 2010

Background

Better understanding the etiology-specific incidence of severe acute respiratory infections (SARIs) in resource-poor, rural settings will help further develop and prioritize prevention strategies. To address this gap in knowledge, we conducted a longitudinal study to estimate the incidence of SARIs among children in rural Bangladesh.

Methods

During June through October 2010, we followed children aged <5 years in 67 villages to identify those with cough, difficulty breathing, age-specific tachypnea and/or danger signs in the community or admitted to the local hospital. A study physician collected clinical information and obtained nasopharyngeal swabs from all SARI cases and blood for bacterial culture from those hospitalized. We tested swabs for respiratory syncytial virus (RSV), influenza viruses, human metapneumoviruses, adenoviruses and human parainfluenza viruses 1–3 (HPIV) by real-time reverse transcription polymerase chain reaction. We calculated virus-specific SARI incidence by dividing the number of new illnesses by the person-time each child contributed to the study.

Results

We followed 12,850 children for 279,029 person-weeks (pw) and identified 141 SARI cases; 76 (54%) at their homes and 65 (46%) at the hospital. RSV was associated with 7.9 SARI hospitalizations per 100,000 pw, HPIV3 2.2 hospitalizations/100,000 pw, and influenza 1.1 hospitalizations/100,000 pw. Among non-hospitalized SARI cases, RSV was associated with 10.8 illnesses/100,000 pw, HPIV3 1.8/100,000 pw, influenza 1.4/100,000 pw, and adenoviruses 0.4/100,000 pw.

Conclusion

Respiratory viruses, particularly RSV, were commonly associated with SARI among children. It may be useful to explore the value of investing in prevention strategies, such as handwashing and respiratory hygiene, to reduce respiratory infections among young children in such settings.

Risk factors for cardiomyopathy syndrome (CMS) in Norwegian salmon farming

Cardiomyopathy syndrome (CMS) has been an economically important disease in Norwegian aquaculture since the 1990s. In this study, data on monthly production characteristics and case registrations were combined in a cohort study and supplemented with a questionnaire-based case-control survey on management factors in order to identify risk factors for CMS. The cohort study included cases and controls from 2005 to 2012. From this dataset differences between all cases and controls were analyzed by a mixed effect multivariate logistic regression. From this we found that the probability of CMS increased with increasing time in the sea, infection pressure, and cohort size, and that cohorts which had previously been diagnosed with heart and skeletal muscle inflammation or which were in farms with a history of CMS in previous cohorts had double the odds of developing CMS. The model was then used to calculate the predicted value for each cohort from which additional data were obtained via the questionnaire-based survey and used as offset for calculating the probability of CMS in a semi-univariate analysis of additional risk factors. Finally, the model was used to calculate the probability of developing CMS in 100 different scenarios in which the cohorts were subject to increasingly worse conditions with regards to the risk factors from the dataset. We believe that this exercise is a good way of communicating the findings to farmers, so they can make informed decisions when trying to avoid CMS in their fish cohorts.

Detection and characterization of potentially zoonotic viruses in faeces of pigs at slaughter in Germany

Pigs can harbour a variety of viruses in their gastrointestinal tract. Some of them are closely related to human viruses and are therefore suspected to have a zoonotic potential. Only little is known about the presence of those viruses in pigs at slaughter. However, by contamination of meat with zoonotic viruses during the slaughtering process, food-borne transmission to humans may be possible. Here we analyzed 120 faecal samples of pigs at slaughter from 3 different geographical regions of Germany for the presence of astrovirus (AstV), encephalomyocarditis virus (EMCV), hepatitis E virus (HEV), norovirus genogroup II (NoV GII) and group A rotavirus (GARV). Using real-time RT-PCR, the most frequently detected virus was AstV, which was present in 20.8% of the samples, followed by NoV GII with a detection rate of 14.2%. EMCV, HEV and GARV were found only occasionally with detection rates of 4.2%, 2.5% and 0.8%, respectively. Analyses of partial genome sequences of the viruses indicated that the detected AstV and NoV GII mainly represented typical pig virus strains, which have not been detected in humans so far. However, the GARV and HEV strains were more closely related to human strains. The results indicate that enteric viruses, some of them with zoonotic potential, are present in pig faeces at slaughter. Application of good hygiene practice is necessary to minimize the risk of introducing these viruses into the food and to prevent virus transmission to highly exposed persons such as slaughterers and veterinarians.

Ecological and taxonomic variation among human RNA viruses

Only a minority of RNA viruses that can infect humans are capable of spreading in human populations independently of a zoonotic reservoir. This is especially true of vector-borne RNA viruses; the majority of these are not transmissible (via the vector) between humans at all. Understanding the biology underlying this observation will help us evaluate the public health risk associated with novel vector-borne RNA viruses.

Piscine myocarditis virus (PMCV) in wild Atlantic salmon Salmo salar

Cardiomyopathy syndrome (CMS) is a severe cardiac disease of sea-farmed Atlantic salmon Salmo salar L., but CMS-like lesions have also been found in wild Atlantic salmon. In 2010 a double-stranded RNA virus of the Totiviridae family, provisionally named piscine myocarditis virus (PMCV), was described as the causative agent of CMS. In the present paper we report the first detection of PMCV in wild Atlantic salmon. The study is based on screening of 797 wild Atlantic salmon by real-time RT-PCR. The samples were collected from 35 different rivers along the coast of Norway, and all individuals included in the study were classified as wild, based on visual appearance and scale reading. Two samples tested positive during PCR analysis, and the results were confirmed by sequencing.

Picobirnavirus infections: viral persistence and zoonotic potential

Picobirnaviruses (PBVs) are small, non-enveloped, bisegmented double-stranded RNA genomic viruses of vertebrate hosts. Since their discovery in the late 1980s in clinical specimens from outbreaks of acute gastroenteritis in children, significant efforts have been made to investigate the role of PBV in diarrheic diseases. PBV has been detected in sporadic episodes of diarrhea as sole pathogen or coinfection as well as in outbreaks of acute gastroenteritis and in immunocompromised patients with diarrhea. However, PBV is frequently detected in non-diarrheic healthy hosts, and prolonged shedding has been observed in some individuals. Of interest, similar patterns of PBV infection have also been observed in pigs and other animal hosts. The increasing amount of PBV sequence data gathered from molecular epidemiological studies has evidenced a great sequence diversity of PBVs in various hosts and environmental samples. Importantly, evidence has been found for genetic relatedness between human and animal PBV strains, suggesting extant crossing points in the ecology and evolution of heterologous PBV strains. At present, no cell culture and animal model exists for PBVs. Well-structured epidemiological studies are still the only alternative to demonstrate the potential etiological role of PBVs in acute gastroenteritis or other diseases. This review aims to analyze the public health aspects of PBV infection, especially its possible association with zoonosis.

A wide variety of diarrhea viruses circulating in pediatric patients in Thailand

BACKGROUND

Viral gastroenteritis has been recognized as one of the most common illnesses that affects infants and young children all over the world. A wide variety of viruses associated with the disease are continually being reported. To investigate the epidemiological situation of diarrhea virus infection in Chiang Mai, Thailand, surveillance was conducted during January to December 2007.

METHODS

A total of 160 fecal specimens collected from pediatric patients admitted to the hospital with acute gastroenteritis were tested for the presence of group A, B, and C rotaviruses, norovirus, sapovirus, astrovirus, adenovirus, Aichi virus, enterovirus, bocavirus, and human parechovirus by RT-multiplex PCR.

RESULTS

Of 160 fecal specimens tested, 85 (53.1%) were positive for diarrhea viruses. Of these, group A rotavirus was the predominant with a prevalence of 27.5%, followed by norovirus GII (11.9%), sapovirus (3.1%), enterovirus (2.5%), human parechovirus (1.9%), and norovirus GI, astrovirus, adenovirus (each 0.6%). Mixed-infections of 2 or 3 viruses were observed in 7 (4.4%) patients. However, none of groups B and C rotaviruses and Aichi virus were detected in this study. Monthly distribution analysis revealed that all those diarrhea viruses were detected continually throughout the year at a low level of infection except for group A rotavirus and norovirus infections which appeared to peak in a cool season in January-March and December, respectively.

CONCLUSIONS

This surveillance revealed a wide variety of diarrhea viruses currently circulating in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand.

Epidemiology of influenza-like illness during Pandemic (H1N1) 2009, New South Wales, Australia

To rapidly describe the epidemiology of influenza-like illness (ILI) during the 2009 winter epidemic of pandemic (H1N1) 2009 virus in New South Wales, Australia, we used results of a continuous population health survey. During July-September 2009, ILI was experienced by 23% of the population. Among these persons, 51% were unable to undertake normal duties for <3 days, 55% sought care at a general practice, and 5% went to a hospital. Factors independently associated with ILI were younger age, daily smoking, and obesity. Effectiveness of prepandemic seasonal vaccine was ?20%. The high prevalence of risk factors associated with a substantially increased risk for ILI deserves greater recognition.

Natural history of chronic hepatitis B

In this article, the 4 phases of chronic HBV infection are reviewed and the factors that are associated with disease progression and the development of hepatocellular carcinoma (HCC) and cirrhosis are discussed. Also discussed is what is known to date about how to identify persons at the highest risk of developing HCC and/or cirrhosis. Finally, ways in which the natural history can be altered by hepatitis B vaccination and identification, close monitoring, and appropriate treatment of chronically infected individuals are reviewed.

Characterization of a Taura syndrome virus isolate originating from the 2004 Texas epizootic in cultured shrimp

A comprehensive investigation of the Taura syndrome virus (TSV) isolate that caused epizootics in shrimp farms in Texas in 2004 (Texas isolate) revealed that this virus was more virulent in laboratory bioassays than the TSV reference isolate, Hawaii 1994, causing severe symptom development and rapid mortality. Histopathology of moribund animals demonstrated epithelial necrosis within the stomach, appendages, general body cuticle and gills, and the surviving animals demonstrated moderate to numerous lymphoid organ spheroids. Purified virions showed icosahedral morphology, with a diameter of 31 nm. Comparative genome analysis showed that the Texas isolate is more closely related to TSV isolates from Thailand and China than to the Hawaii isolate. The predicted tertiary structures of the inhibition of apoptosis protein (IAP) and protease domains of the Texas isolate are very similar to those of the Hawaii isolate. However, the RNA-dependent RNA polymerase (RdRp) of the Texas isolate has significant structural differences from the Hawaii isolate due to point mutation(s) in the RdRp gene. Changes in the RdRp tertiary structure might contribute to the replication fidelity, virulence and ecological adaptability of the Texas isolate.

Phylogenetic analysis of betanodavirus isolates from Australian finfish

In Australia, disease caused by betanodavirus has been reported in an increasing number of cultured finfish since the first report of mortalities in 1990. Partial coat protein gene sequences from the T2 or T4 regions of 8 betanodaviruses from barramundi Lates calcarifer, sleepy cod Oxyeleotris lineolata, striped trumpeter Latris lineata, barramundi cod Cromileptes altivelis, Australian bass Macquaria novemaculata and gold-spotted rockcod Epinephelus coioides from several Australian states were determined. Analysis of the 606 bp nucleotide sequences of the T2 region of 4 isolates demonstrated the close relationship with isolates from the red-spotted grouper nervous necrosis virus (RGNNV) genotype and the Cluster Ia subtype. Comparison of a smaller 289 bp sequence from the T4 region identified 2 distinct groupings of the Australian isolates within the RGNNV genotype. Isolates from barramundi from the Northern Territory, barramundi, sleepy cod, barramundi cod and gold-spotted rockcod from Queensland, and striped trumpeter from Tasmania shared a 96.2 to 99.7% nucleotide identity with each other. These isolates were most similar to the RGNNV genotype Cluster Ia. Isolates from Australian bass from New South Wales and from barramundi from South Australia shared a 98.6% sequence identity with each other. However, these isolates only shared an 85.8 to 87.9% identity with the other Australian isolates and representative RGNNV isolates. The closest nucleotide identity to sequences reported in the literature for the New South Wales and South Australian isolates was to an Australian barramundi isolate (Ba94Aus) from 1994. These 2 Australian isolates formed a new subtype within the RGNNV genotype, which is designated as Cluster Ic.

Outbreak of betanodavirus infection in tilapia, Oreochromis niloticus (L.), in fresh water

A betanodavirus associated with a massive mortality was isolated from larvae of tilapia, Oreochromis niloticus, maintained in fresh water at 30 degrees C. Histopathology revealed vacuolation of the nervous system, suggesting an infection by a betanodavirus. The virus was identified by indirect fluorescent antibody test in the SSN1 cell line and further characterized by sequencing of a PCR product. Sequencing of the T4 region of the coat protein gene indicated a phylogenetic clustering of this isolate within the red-spotted grouper nervous necrosis virus type. However, the tilapia isolate formed a unique branch distinct from other betanodavirus isolates. The disease was experimentally reproduced by bath infection of young tilapia at 30 degrees C. The reservoir of virus at the origin of the outbreak remains unidentified. To our knowledge, this is the first report of natural nodavirus infection in tilapia reared in fresh water.

Prospective study of etiologic agents of acute gastroenteritis outbreaks in child care centers

OBJECTIVE

To investigate the etiology of outbreaks of acute gastroenteritis (AGE) in children attending childcare centers (CCCs) in North Carolina between October 2005 and March 2007.

STUDY DESIGN

In this prospective study of outbreaks of AGE in CCCs, stool specimens from symptomatic children and environmental surface swabs were tested for adenovirus group F, astrovirus, norovirus (NoV), rotavirus group A, and sapovirus using real-time and conventional reverse transcription-polymerase chain reaction assays, and viruses were genotyped by sequencing.

RESULTS

A total of 29 AGE outbreaks were evaluated, of which 13 (45%) were caused by a single virus, including rotavirus group A (17%), NoV (10%), astrovirus (10%), and sapovirus (7%). Multiple viruses were detected in 3 outbreaks (10%). Environmental swabs from 13 of 22 outbreaks (59%) tested positive for at least 1 virus and confirmed the findings of the same virus in the fecal specimens for 10 of the outbreaks (45%).

CONCLUSIONS

This study confirms that viruses are major causes of AGE outbreak in CCCs. Our finding of widespread environmental contamination during such outbreaks suggests the need to study the effectiveness of current surface disinfectants against multiple gastroenteritis viruses in CCCs.

Serosurvey of five viruses in chickens on smallholdings in Bangladesh

A serologic survey was undertaken in chickens in smallholdings in Bangladesh for avian influenza A virus (AIV), egg drop syndrome '76 virus (EDS'76V), infectious bronchitis virus (IBV), Newcastle disease virus (NDV) and reovirus (RV) in three phases: January 2002-May 2003, September 2003-August 2004, and August 2005-March 2006. Four hundred thirty-six sera collected in the 2nd phase, 295 in the first phase, 755 in the 1st plus 2nd phases and 295 in the 1st phase were investigated for AIV, EDS'76V, IBV and RV, respectively, using enzyme linked immunosorbent assays. All 854 sera collected in the three phases were screened for NDV using hemagglutination inhibition test. In chickens 20% were seropositive to AIV, 3% to EDS'76V, 74% to IBV, 88% to NDV, and 47% to RV. The seroprevalence in flocks was 23% to AIV, 6% to EDS'76V, 79% to IBV, 89% to NDV and 56% to RV. Twenty-five percent chickens had > or = 10log(2)HI titers to NDV.

[Epidemiology of acute upper and lower respiratory tract infections in children]

More than 200 antigenically distinct viruses have been documented as causes of sporadic or epidemic respiratory infections in infants and children. The lung itself is rarely sampled directly, and sputum representing lower-airway secretions can rarely be obtained from children. In addition culture of secretions from upper respiratory tract is not useful since the normal flora includes the bacteria commonly responsible for pneumonia. Clinical and radiology data only suggest the diagnosis. The development of techniques to detect antigens of the causative agent in nasopharyngeal secretions, nucleic acid by means of the polymerise-chain reaction assays has significantly improved the identification of the responsible pathogen and the choice of appropriate treatment. Since more 30 years rhinovirus, coronavirus, enterovirus, parainfluenza virus and respiratory syncytial virus were added to influenza, adenovirus and measles virus as causes of respiratory tract infections. This list of pathogens was extended last years with the discovery of human metapneumovirus, bocavirus, polyomavirus. In restricted patient groups, such as the immunocompromised, members of the family of herpesvirus have also been associated with respiratory disease.