Viral Diseases of Strawberry

Viral diseases in strawberry are not easily detected because most single virus infections are symptomless on commercial cultivars. However, virus outbreaks have the potential for epidemics and economic losses. A mixed virus infection of Strawberry Mild Yellow Edge Virus (SMYEV) and Strawberry Mottle Virus (SMoV) was identified in several southeastern states during the 2012-13 season, resulting in millions of dollars in losses. This updated version of a previous publication offers basic information on viral diseases of strawberry, with emphasis on viruses of potential threat to the strawberry industry in Florida. The primary target audience of this publication includes growers and industry personnel, extension agents and pathologists working with strawberry. Originally published April 2010: Moyer, Catalina, Vance Whitaker, and Natalia Peres. 2010. “Viral Diseases of Strawberries”. EDIS 2010 (4). https://journals.flvc.org/edis/article/view/118602.

Identification of Mixed Virus Infection on Trichosanthes cucumerina L. in Akamkpa, Southern Cross River State, Nigeria

Trichosanthes cucumerina L is a tropical or subtropical fruit bearing crop of the Cucurbitaceae family. Field survey during 2020 planting season in Akamkpa, Southern Cross River State, Nigeria revealed widespread virus infection of the crop. Symptoms observed included severe leaf malformation/reduction and rugosity. This research was therefore aimed at identifying viruses infecting Trichosanthes cucumerina in this location. Infected leaf samples were collected and virus maintained on young seedlings of T. cucumerina in the Botanical Garden of University of Calabar, Nigeria. Diagnostic tools included ACP-ELISA and gene sequence analysis. The ELISA result revealed two viruses belonging to the genus Cucumovirus and Potyvirus. The identity of the viruses were determined after virus sequences were compared with other viruses available in the GenBank of National Centre for Biotechnology Information (NCBI) using the basic local alignment search tool (BLASTn). The result revealed the Cucumovirus to be Cucumber mosaic virus (CMV) while the Potyvirus was revealed to be Potato virus Y (PVY). This is the first report of mixed virus infection on Trichosanthes cucumerina in Nigeria.

Etiology, clinical characteristics and coinfection status of bronchiolitis in Suzhou

Background Bronchiolitis is a clinical syndrome commonly encountered in practice, particularly among infants and young children. To investigate the prevalence of pathogens in hospitalized children with bronchiolitis and study the clinical characteristics of bronchiolitis with or without coinfections. Methods We investigated the respiratory specimens and clinical data of 1012 children with bronchiolitis who were treated at the Children’s Hospital of Soochow University between November 2011 and December 2018. The nasopharyngeal aspirates were examined to detect viruses by direct immunofluorescence assay or polymerase chain reaction (PCR). Mycoplasma pneumoniae (MP) was tested by PCR and enzyme-linked immunosorbent assay. Results Of the 1134 children less than 2 years with bronchiolitis, 122 were excluded by exclusion criteria. Causative pathogen was detected in 83.2% (842 of 1012). The majority of these (614 [72.9%] of 842) were single virus infection. The most common pathogens detected were respiratory syncytial virus (RSV) (44.4%), MP (15.6%), and human rhinovirus (HRV) (14.4%). Coinfection was identified in 13.5% (137 of 1012) of the patients. Coinfection included mixed virus infection and virus infection with MP infection. Children with single virus infection had a higher rate of oxygen therapy compared with single MP infection. Conclusions The most common pathogen detected in children with bronchiolitis is RSV, followed by MP and HRV. Coinfection leads to a longer period of illness, increased severity of the symptoms and increased risk of hypoxemia.

Etiology, clinical characteristics and coinfection status of bronchiolitis in Suzhou

Background: Bronchiolitis is a clinical syndrome commonly encountered in practice, particularly among infants and young children. To investigate the prevalence of pathogens in hospitalized children with bronchiolitis and study the clinical characteristics of bronchiolitis with or without coinfections. Methods: We investigated the respiratory specimens and clinical data of 1012 children with bronchiolitis who were treated at the Children’s Hospital of Soochow University between November 2011 and December 2018. The nasopharyngeal aspirates were examined to detect viruses by direct immunofluorescence assay or polymerase chain reaction (PCR). Mycoplasma pneumoniae (MP) was tested by PCR and enzyme-linked immunosorbent assay. Results: Of the 1134 children less than 2 years with bronchiolitis, 122 were excluded by exclusion criteria. Causative pathogen was detected in 83.4% (842 of 1012). The majority of these (614 [72.9%] of 842) were single virus infection. The most common pathogens detected were respiratory syncytial virus (RSV) (44.4%), MP (15.6%), and human rhinovirus (HRV) (14.4%). Coinfection was identified in 13.5% (137 of 1012) of the patients. Coinfection included mixed virus infection and virus infection with MP infection. Children with single virus infection had a higher rate of oxygen therapy compared with single MP infection. Conclusions: The most common pathogen detected in children with bronchiolitis is RSV, followed by MP and HRV. Coinfection leads to a longer period of illness, increased severity of the symptoms and increased risk of hypoxemia.

Etiology, clinical characteristics and coinfection status of bronchiolitis in Suzhou

Background: Bronchiolitis is a clinical syndrome commonly encountered in practice, particularly among infants and young children. To investigate the prevalence of pathogens in hospitalized children with bronchiolitis and study the clinical characteristics of bronchiolitis with or without coinfections. Methods: We investigated the respiratory specimens and clinical data of 1012 children with bronchiolitis who were treated at the Children’s Hospital of Soochow University between November 2011 and December 2018. The nasopharyngeal aspirates were examined to detect viruses by direct immunofluorescence assay or polymerase chain reaction (PCR). Mycoplasma pneumoniae (MP) was tested by PCR and enzyme-linked immunosorbent assay.Results: Of the 1012 children less than 2 years with bronchiolitis, causative pathogen was detected in 83.4% (842 of 1012). The majority of these (614 [72.9%] of 842) were single virus infection. The most common pathogens detected were respiratory syncytial virus (RSV) (44.4%), MP (15.6%), and human rhinovirus (HRV) (14.4%). Coinfection was identified in 13.5% (137 of 1012) of the patients. Coinfection includes virus mixed virus infection and virus mixed MP infection. Children with single virus infection had a higher rate of oxygen therapy compared with single MP infection. Conclusions: The most common pathogen detected in children with bronchiolitis is RSV, followed by MP and HRV. The high mix infection burden in bronchiolitis underscores a need for the sensitive and rapid diagnostics to accurately identify pathogens.

Specific and Spillover Effects on Vectors Following Infection of Two RNA Viruses in Pepper Plants

Mixed infection of plant viruses is ubiquitous in nature and can affect virus–plant–vector interactions differently than single virus infection. While several studies have examined virus–virus interactions involving mixed virus infection, relatively few have examined effects of mixed virus infection on vector preference and fitness, especially when multiple vectors are involved. This study explored how single and mixed viral infection of a non-persistently transmitted cucumber mosaic virus (CMV) and propagative and persistently-transmitted tomato spotted wilt orthotospovirus (TSWV) in pepper, Capsicum annum L., influenced the preference and fitness of their vectors, the green peach aphid, Myzus persicae (Sulzer), and the tobacco thrips, Frankliniella fusca (Hinds), respectively. In general, mixed infected plants exhibited severe symptoms compared with individually infected plants. An antagonistic interaction between the two viruses was observed when CMV titer was reduced following mixed infection with TSWV in comparison with the single infection. TSWV titer did not differ between single and mixed infection. Myzus persicae settling preference and median developmental were not significantly different between CMV and/or TSWV-infected and non-infected plants. Moreover, M. persicae fecundity did not differ between CMV-infected and non-infected pepper plants. However, M. persicae fecundity was substantially greater on TSWV-infected plants than non-infected plants. Myzus persicae fecundity on mixed-infected plants was significantly lower than on singly-infected and non-infected plants. Frankliniella fusca fecundity was higher on CMV and/or TSWV-infected pepper plants than non-infected pepper plants. Furthermore, F. fusca-induced feeding damage was higher on TSWV-infected than on CMV-infected, mixed-infected, or non-infected pepper plants. Overall, our results indicate that the effects of mixed virus infection on vectors were not different from those observed following single virus infection. Virus-induced host phenotype-modulated effects were realized on both specific and non-specific vectors, suggesting crosstalk involving all vectors and viruses in this pathosystem. The driving forces of these interactions need to be further examined. The effects of interactions between two viruses and two vectors towards epidemics of one or both viruses also need to be examined.

PECULIARITIES OF MIXED RESPIRATORY VIRAL INFECTIONS IN WOMEN IN THE SECOND TRIMESTER OF PREGNANCY UNDER INTRAUTERINE INFECTION OF THEIR NEWBORNS WITH CEREBRAL ISCHEMIA

Clinical and serological features of the gestational process in 85 women with pregnancy, uncomplicated and complicated with parainfluenza-influenza infection in the second trimester of gestation, were studied. All examined women were divided into three groups. The first group (control) included 32 women with physiological course of pregnancy and their healthy full-term newborns. The second group included 32 patients with respiratory mixed-virus infection in the second trimester of gestation, and in their newborns there was diagnosed moderate cerebral ischemia and no signs of intrauterine infection. The third group included 21 women with respiratory mixed virus infection in the second trimester of pregnancy, which was the cause of antenatal infection in their full-term infants with cerebral ischemia of moderate severity. It was shown that the women of the third group compared with the second and first groups often complained of headache, photophobia, sweating and weakness, increase in body temperature to 37.6-38ºC, hoarseness of the voice, sore throat, as well as a prolonged course of acute nasopharyngitis and acute laryngitis. The above clinical features of acute respiratory viral infection in women in the second trimester of gestation may contribute to antenatal infection and may disrupt optimal conditions for intrauterine brain development in their babies.

Characterization of Blueberry shock virus, an Emerging Ilarvirus in Cranberry

Blueberry shock virus (BlShV), an Ilarvirus sp. reported only on blueberry, was associated with scarring, disfigurement, and premature reddening of cranberry fruit. BlShV was detected by triple-antibody sandwich enzyme-linked immunosorbent assay and reverse-transcription polymerase chain reaction, and isometric virions of 25 to 28 nm were observed in cranberry sap. The virus was systemic, although unevenly distributed in plants. The coat protein of BlShV from cranberry shared 90% identity compared with BlShV accessions from blueberry on GenBank. Phylogenetic analysis of isolates of BlShV from cranberry collected from Wisconsin and Massachusetts did not indicate grouping by state. BlShV was detected in cranberry pollen, and seed transmission of up to 91% was observed. Artificial inoculation of cranberry flowers by pollination did not cause virus transmission. In some Nicotiana spp., rub inoculation of leaves with homogenized BlShV-positive cranberry flowers resulted in systemic infection. Cranberry plants recovered from symptoms the year after berry scarring occurred but continued to test positive for BlShV. The virus caused significant reduction in the average number of marketable fruit and average berry weight in symptomatic cranberry plants but recovered plants yielded comparably with healthy plants. Although recovery may limit the immediate economic consequences of BlShV, long-term implications of single- or mixed-virus infection in cranberry is unknown.

A Reliable and Rapid Multiplex RT-PCR Assay for Detection of Two Potyviruses and a Pararetrovirus Infecting Canna Plants

Canna plants are subject to serious virus diseases. The three most common viruses identified in canna plants are Bean yellow mosaic virus, Canna yellow mottle virus, and Canna yellow streak virus. Recent studies indicate that canna plants are commonly infected with more than one virus. Thus, the efficient control of these viruses in canna plants requires the availability of a reliable method for detecting mixed virus infection. This report presents a two-step multiplex reverse-transcription polymerase chain reaction (RT-PCR) that was developed to simultaneously detect two potyviruses and one pararetrovirus genome. We optimized the method for nucleic acid isolation for managing a large population of samples, and the primer concentrations to ensure sensitivity and reliability of the assay, and determined the detection limit in simplex and multiplex RT-PCR assays using plasmid controls and nucleic acids isolated from virus-infected plants. Combined with an automated method for total nucleic acid isolation, this multiplex RT-PCR procedure could be routinely used for virus detection in research and diagnostic laboratories.