Molecular characterization of Brazilian isolates of orf virus

An evaluation of the ecological niche of Orf virus (Poxviridae): Challenges of distinguishing broad niches from no niches

Contagious ecthyma is a skin disease, caused by Orf virus, creating great economic threats to livestock farming worldwide. Zoonotic potential of this disease has gained recent attention owing to the re-emergence of disease in several parts of the world. Increased public health concern emphasizes the need for a predictive understanding of the geographic distributional potential of Orf virus. Here, we mapped the current distribution using occurrence records, and estimated the ecological niche in both geographical and environmental spaces. Twenty modeling experiments, resulting from two- and three-partition models, were performed to choose the candidate models that best represent the geographic distributional potential of Orf virus. For all of our models, it was possible to reject the null hypothesis of predictive performance no better than random expectations. However, statistical significance must be accompanied by sufficiently good predictive performance if a model is to be useful. In our case, omission of known distribution of the virus was noticed in all Maxent models, indicating inferior quality of our models. This conclusion was further confirmed by the independent final evaluation, using occurrence records sourced from the Centre for Agriculture and Bioscience International. Minimum volume ellipsoid (MVE) models indicated the broad range of environmental conditions under which Orf virus infections are found. The excluded climatic conditions from MVEs could not be considered as unsuitable owing to the broad distribution of Orf virus. These results suggest two possibilities: that the niche models fail to identify niche limits that constrain the virus, or that the virus has no detectable niche, as it can be found throughout the geographic distributions of its hosts. This potential limitation of component-based pathogen-only ENMs is discussed in detail.

Clinicopathological and molecular studies on cattle naturally infected with lumpy skin diseases in selected districts of Wolaita Zone, Southern Ethiopia

Background

Lumpy skin disease is a contagious viral disease of cattle caused by LSDV that results in huge economic losses in the cattle industry. This study characterizes LSDV in cattle through clinicopathological and molecular techniques in selected districts of Wolaita Zone, Southern Ethiopia.

Methods

A crossectional study was conducted from November 2020 to June 2021 using Real-time polymerase chain reaction and Histopathological techniques to confirm LSDV.

Result

This study revealed that the percentage of positivity of cattle for LSDV was 36.2%. Clinically, cattle infected with LSDV revealed fever (39–41 °C), nodular lesions on the skin and mucous membranes, and lymphadenopathy. Histopathologically, affected tissue revealed ballooning degenerations of the epidermis, infiltration of mononuclear inflammatory cells, vasculitis, and intracytoplasmic eosinophilic inclusion bodies. RT-PCR confirmed that DNA extracts from skin biopsies of virus isolates were positive for LSDV.

Conclusion

The present study confirms that LSDV is widely circulating in cattle of selected districts of the Wolaita zone. Thus, effective control measures through regular vaccination and further confirmation of circulating strains of LSDV through detailed molecular analysis should be recommended.

Detection of contagious ovine ecthyma (orf) and risk factors for infection in small ruminants in Iran

The primary cause of contagious ecthyma is the orf virus, the parapoxvirus prototype. It is a viral problem observed in goat and sheep flocks in Iran, causing economic loss. Orf is a zoonosis with little epidemiological investigation present in Iran. The current research aims at determining the status of this virus, and a PCR was used as a confirmatory instrument. We sampled 668 goats and sheep and various breeding systems. Besides, the orf prevalence was studied, and vaccination efficacy was determined. Moreover, the potential risk factors surveyed for infection with ecthyma were identified. Samples were taken from goat and sheep flocks in the present cross-sectional research, and PCR was used for testing orf DNA. A checklist including animals' general information was completed. Data were analyzed using univariate tests (chi-square and t-tests) and multivariable binary logistic regression analysis. Three hundred one (45%) goats and sheep detected orf DNA. The age of 70% of positive cases was below one month. Ecthyma infection was significantly higher in imported breeds (87.3%) than indigenous (39.3%). Ninety-six percent of infected goats and sheep in the present work were not vaccinated against ecthyma. The high prevalence of the orf virus was confirmed among goat and sheep flocks in Iran. It is necessary to train ranchers regarding sanitary actions, quarantine, and application of orf vaccination plans.

First detection and molecular characterisation of pseudocowpox virus in a cattle herd in Zambia

Background

Pseudocowpox virus (PCPV) of the genus Parapoxvirus in the family Poxviridae causes pseudocowpox in cattle worldwide and presents a zoonotic concern. Most poxviruses produce diseases of similar clinical signs in affected animals, which are impossible to differentiate clinically or by serology. It is, therefore, vital to use molecular assays to rapidly identify the causative agents of poxvirus infections. This study aimed to detect, diagnose, and characterize the causative agent of pox-like skin lesions in a cattle herd in Zambia, initially suspected to be infected with Lumpy Skin Disease virus.

Methods

We used a High-Resolution Melting (HRM) analysis assay to detect the PCPV genome and sequenced the major envelope protein (B2L gene) for comparative sequence and phylogenetic analysis.

Results

Our field investigations showed cattle presenting atypical skin lesions and high morbidity within the herd. The laboratory diagnosis, based on the HRM assay revealed PCPV DNA in the samples. Phylogenetic and comparative sequence analyses confirmed PCPV in the samples and revealed genomic differences between samples collected in 2017 and 2018 from the same farm.

Conclusion

Our work is the first documented report of PCPV in Zambia. It shows the strength of molecular methods to diagnose pox-like infections in cattle and discriminate between diseases causing similar clinical signs. This rapid and accurate diagnosis improves the response time for more accurate veterinary interventions.

An association of Orf virus infection among sheep and goats with herd health programme in Terengganu state, eastern region of the peninsular Malaysia

BACKGROUND

Orf virus causes a scabby skin lesions which decreases productivity in small ruminants. The unknown status of this disease in the eastern region of Peninsular Malaysia warrants a study to determine sero-prevalence of orf with regards to farmers' compliance level towards the Herd Health Program (HHP) programme.

RESULTS

Out of 504 animals, 115 were positive for Orf-virus antibodies. An overall prevalence rate of 22.8% indicated a high prevalence of orf disease in this region. It was observed that 25.1% (92/367) of goats were positive and 16.8% (23/137) of sheep sero-converted for Orf virus antibody. Several factors were measured for their possible association with prevalence of Orf virus infection. The prevalence was higher in LY farm, JC breed, kid and female animals, and in the presence of disease lesion. Chi-square analysis showed a significant association of three risk factors which are species, age and sex of the animals (P < 0.05). Notwithstanding, all other variables showed no significant difference (P > 0.05). Farms surveyed usually practised intensive management system, keeping animals in the shade at all time, due to limited availability of suitable land as a free-range grazing area. An interview with small holder farmers revealed a lack of awareness of the main goals of herd health programme. An overall compliance level of 42.7% was observed for all HHP parameters. Among the 14 main components of HHP modules, animal identification had recorded highest compliance level (84.62%) while milking management recorded the least compliance (- 82.69%). That explained why there was a high sporadic prevalence of Orf infection in this region.

CONCLUSION

Good herd health supervision is a rehearsal target to prevent an outbreak and the spread of diseases thus reduces economic losses among farmers. Therefore, a good herd health programme should be in place, in order to prevent and control disease transmission as well as to improve herd immunity.

Comparison of the sensitivity of three cell cultures to ORFV

Background

Contagious ecthyma (CE) appears in the countries and regions containing goat and sheep farms, and it is considered a global epidemic. CE not only severely endangers the healthy development of the sheep and goat industries but also threatens human health. For viral infectious diseases, fast and effective isolation and culture of the pathogen is critical for CE diagnosis, and for disease prevention and control. Therefore, the sensitivity of bovine Sertoli cells to ORFV was estimate in this study.

Results

The sensitivities of bovine Sertoli cells, primary neonatal bovine testicular cells, and Madin-Darby bovine kidney (MDBK) cell line to ORFV were compared. Our results showed that the isolated bovine Sertoli cells were sensitive to inoculated ORFV, and viral titers were approximately 1 log higher than those in primary neonatal bovine testicular cells and in MDBK cell lines.

Conclusion

Appropriately sensitive cells for the highly efficient isolation and culture of the ORFV were obtained. Culture of ORFV using the Sertoli cells showed good consistency and stability and also avoided the risk of other pathogens presenting during viral culture using a primary cell line. In addition, using these passaged bovine Sertoli cells to proliferate ORFV may simplify the CE diagnosis process, thereby reducing detection time and cost. Hence, this test has important practical significance for the diagnosis of CE and the research on the pathogenic mechanism of ORFV.

Dermatopathology of Orf Virus (Malaysian Isolates) in Mice Experimentally Inoculated at Different Sites with and without Dexamethasone Administration

Orf is a clinical manifestation of parapoxvirus infection often fatal in goats and sheep especially when they are under stress or influenced by unfavorable environment. This study investigated the pathogenicity of two Orf virus isolates (ORFV UPM1/14 and UPM2/14) and host response in mouse model by using different inoculation sites with/without prior exposure to dexamethasone. Treatments with dexamethasone served as an immunosuppressant that may mimic stress situation in affected animals. Groups of five mice were given intradermal injection of 0.2 mL of tissue culture infective dose 50 (TCID₅₀) of UPM1/14 (Group 1) and UPM2/14 (Group 2) at the dorsum (Group 1A; Group 2A), ear pinna (Group 1B; Group 2B), and labial commissure (Group 1C; Group 2C). An inoculum 0.2 mL of UPM1/14 was administered to animals treated with dexamethasone (n=5; 5 mg/kg/day intraperitoneally) and nondexamethasone (n=5) groups at the dorsum, ear pinna, and labial commissure. No significant difference (p>0.05) was observed in the mean lesion scores among the groups of different inoculation sites or between dexamethasone-treated and nontreated groups. However, there was a significant difference (p<0.05) in the mean stratum thickness of affected skin following inoculation with UPM2/14 isolate at the ear pinna and labial commissure. Histopathology examination revealed keratosis, acanthosis, and ballooning degeneration in the skin of affected mice. Orf virus DNA was detected in the skin samples by targeting F1L and B2L virus-specific genes in polymerase chain reaction (PCR) assay. Intradermal inoculation with UPM1/14 or UPM2/14 isolate produced a mild skin lesion in mice, and there was no significant difference in orf disease manifestation despite variation of inoculation sites. Similarly, short-term dexamethasone administration gave no adverse effects on pathogenicity of orf virus isolates.

Genetic diversity of Orf virus isolated from sheep in Uruguay

Orf virus (ORFV) is the etiological agent of contagious ecthyma, a disease widely spread in the world that occasionally causes zoonotic infections. This work is the first molecular characterization of ORFV in Uruguay, where we analyzed twenty-one sheep samples, eighteen of which were recovered from thirteen ORFV outbreaks that occurred during 2004 to 2011 as well as three strains from a national vaccine. Phylogenetic analysis and the derived amino acid sequences from the B2L gene suggest that the Uruguayan virus do not form a unique cluster, with most of them displaying similarities with worldwide ORFV isolates as well as our vaccine strains.

Diagnosis and phylogenetic analysis of a multifocal cutaneous orf virus with mixed bacterial infection outbreak in goats in Fujian province, China

Outbreaks of orf virus on goat farms are common in China. In this study, we investigated a severe multifocal cutaneous orf virus outbreak with a correlative mixed bacterial infection which persisted for up to 6 months, and which had a high morbidity (93.7%) and mortality (15%) among kids in a herd of crossbreed goats in Fujian province in China. The disease was diagnosed as an orf virus (ORFV XD strain) infection associating with Streptococcus pluranimalium and Staphylococcus, identified using standard virological and bacteriological techniques. Multiple sequence alignments and phylogenetic analyses of the whole ORFV 011 (B2L), 059 (F1L), 032 and 080 genes revealed that the even though the virus phylogeny was clustered in branches of conventional orf virus strains, it nonetheless evidenced high variation within this subset. Furthermore, the sequences from the ORFV 080 gene allowed us to distinguish between the different strains at a higher resolution and these observations afforded us a comparative view of the ORFV 080 gene. This is the first report describing an outbreak of severe multifocal cutaneous orf virus with associated bacterial infection in China.

Detection and quantification of parapoxvirus DNA by use of a quantitative real-time polymerase chain reaction assay in calves without clinical signs of parapoxvirus infection

OBJECTIVE

To investigate the presence of parapoxvirus (PPV) in cattle without clinical signs of infection and in farm environments of PPV-infected cattle.

ANIMALS

28 calves without clinical signs of PPV infection on 2 farms and 11 clinically affected calves on 6 farms.

PROCEDURES

164 oral swab samples were collected at regular intervals from 28 calves without clinical signs of PPV infection, and 11 swab samples were collected from 11 clinically affected calves. Viral DNA load was quantified by use of a PPV-specific quantitative real-time PCR (qRT-PCR) assay. RESULTS Of 28 calves without clinical signs of PPV infection, 12 had positive results for PPV DNA by use of the qRT-PCR assay. Viral DNA was detected continuously over a period of 2 to 5 months from 9 of these 12 calves, particularly from calves with dermatomycosis or respiratory tract disease. The PPV DNA loads in 32 oral swab samples from these 12 calves were significantly lower (median, 3.2 copies/mg) than those in samples collected from the 11 clinically affected calves (median, 3.2 × 10(4) copies/mg). Moreover, PPV DNA was detected in the residual feed and drinking water on both farms that housed the calves without clinical signs of PPV infection.

CONCLUSIONS AND CLINICAL RELEVANCE

PPV in cattle without clinical signs of infection and in the environments of these cattle may represent sources of PPV transmission to susceptible cattle.

IMPACT FOR HUMAN MEDICINE

Humans should wear gloves to prevent zoonotic disease transmission when handling cattle with or without clinical signs of PPV infection.

Development of a lateral flow immunochromatographic assay for the rapid diagnosis of Orf virus infections

A rapid and simple lateral-flow immunochromatographic assay (LFIA) was developed for the specific detection of Orf virus (ORFV) using two distinct monoclonal antibodies (MAbs: 5A5 and 6F2) against the ORFV ORF011 protein. The MAb 5A5 was conjugated with colloidal gold, and the MAb 6F2 and goat anti-mouse IgG were sprayed onto a nitrocellulose membrane in strips at positions designated test (T) and control (C), respectively. The results showed that samples of ORFV complexed with colloidal gold-conjugated MAb 5A5, were captured by MAb 6F2 at the T line resulting in the appearance of a purple band. When samples did not contain ORFV or when they contained a quantity of ORFV below the detection limit of the test, only the C line was visible. The analysis of sensitivity of the test demonstrated that the lowest detected quantity of ORFV was 2.03×10(3.0) TCID50/ml. Storage at room temperature for 6 months did not result in the loss of performance of the LFIA test. Using loop-mediated isothermal amplification (LAMP) as a reference test, the relative specificity and sensitivity of the LFIA test were determined to be 100% and 92.1%, respectively. Based on these results, the LFIA test developed may be a suitable tool for rapid on-site testing for ORFV infection.

Genome analysis of orf virus isolates from goats in the Fujian Province of southern China

Orf virus (ORFV), a species of the genus Parapoxvirus of the family Poxviridae, causes non-systemic, highly contagious, and eruptive disease in sheep, goat, and other wild and domestic ruminants. Our previous work shows orf to be ubiquitous in the Fujian Province of China, a region where there is considerable heterogeneity among ORFVs. In this study, we sequenced full genomes of four Fujian goat ORFV strains (OV-GO, OV-YX, OV-NP, and OV-SJ1). The four strains were 132–139 kb in length, with each containing 124–132 genes and about 64% G+C content. The most notable differences between the four strains were found near the genome termini. OV-NP lacked seven and OV-SJ1 lacked three genes near the right terminus when compared against other ORFVs. We also investigated the skin-virulence of the four Fujian ORFVs in goats. The ORFVs with gene deletions showed low virulence while the ORFVs without gene deletions showed high virulence in goats suggesting gene deletion possibly leads to attenuation of ORFVs. Gene 134 was disrupted in OV-NP genome due to the lack of initial code. The phylogenetic tree based on complete Parapoxviruse genomes showed that sheep originated and goat originated ORFVs formed distinctly separate branches with 100% bootstrap. Based on the single gene phylogenetic tree of 132 genes of ORFVs, 47 genes can be easily distinguished as having originated from sheep or goats. In order to further reveal genetic variation presented in goat ORFVs and sheep ORFVs, we analyzed the deduced amino acid sequences of gene 008, multiple alignment of amino acid sequences of gene 008 from the genome of five goat ORFVs and four sheep ORFVs revealed 33 unique amino acids differentiating it as having sheep or goats as host. The availability of genomic sequences of four Fujian goat ORFVs aids in our understanding of the diversity of orf virus isolates in this region and can assist in distinguishing between orf strains that originate in sheep and goats.

Surveillance of parapoxvirus among ruminants in Virginia and Connecticut

In 2008, two deer hunters in Virginia and Connecticut were infected with a unique strain of pseudocowpox virus, a parapoxvirus. To estimate the prevalence of this virus, and in an attempt to define the reservoir, Parapoxvirus surveillance was undertaken between November 2009 and January 2010. 125 samples from four ruminant species (cows, goat, sheep and white-tailed deer) were collected in Virginia, and nine samples from white-tailed deer were collected in Connecticut. We found no evidence that the parapoxvirus species that infected the deer hunters is circulating among domesticated ruminants or white-tailed deer. However, parapoxvirus DNA of a different parapoxvirus species, bovine papular stomatitis virus (BPSV), was detected in 31 samples obtained from asymptomatic cattle in Virginia. Parapoxvirus DNA-positive cattle originated from the same counties indicating probable transmission among animals. Molecular analysis identified BPSV as the parapoxvirus affecting animals. Asymptomatic parapoxvirus infections in livestock, particularly young animals, may be common, and further investigation will inform our knowledge of virus transmission.

Rapid detection of orf virus by loop-mediated isothermal amplification based on the DNA polymerase gene

At present, there are no effective antiviral treatments available for contagious ecthyma, and rapid diagnosis is therefore critical for effective control of the disease. Recently, the invention of a novel LAMP technique that can rapidly amplify nucleic acids with high specificity and sensitivity under isothermal conditions has overcome some of the deficiencies of nucleic acid-based diagnostic tests and has made on-site diagnosis possible. To establish a flexible loop-mediated isothermal amplification (LAMP) assay for the rapid detection of orf virus, two pairs of primers, including outer primers F3/B3 and inner primers FIP/BIP, were designed to amplify the DNA polymerase gene. Optimal time and temperature conditions for LAMP were found to be 45 min and 62 °C, respectively. The LAMP assay was shown to be specific, with no cross-reactivity with sheeppox virus, goatpox virus, avian molluscum roup virus or vesicular stomatitis virus. Additionally, the sensitivity of the LAMP method was similar to that of real-time PCR and demonstrated greater sensitivity than a conventional polymerase chain reaction (PCR) assay. To assess the utility of LAMP in the detection of orf virus in clinical samples, a total of 35 samples collected from orf virus-infected sheep and goats were tested using the optimized LAMP assay, real-time PCR, and conventional PCR. Of the samples, 26 were found to be positive by LAMP, and 25 (74.3 %) were positive by real-time PCR, whereas only 18 (51.4 %) were positive by conventional PCR. Our results have shown that the LAMP assay developed in this study can be used for the rapid detection of orf virus.

Looking back: a genetic retrospective study of Brazilian Orf virus isolates

Orf virus (ORFV), the prototype of the genus Parapoxvirus, is the aetiological agent of contagious ecthyma (CE), a pustular dermatitis that afflicts domestic and wild small ruminants. CE is one of the most widespread poxvirus diseases in the world, causing public health impacts. Outbreaks of ORFV have been observed in all geographical regions of Brazil, affecting ovine and caprine herds. The origins, epidemiology and identity of Brazilian ORFVs are unknown, and no comparative or phylogenetic studies of these viruses have been performed. In the present study, we revisited CE outbreaks which occurred until 32 years ago, and we assessed, genetically, five viral isolates. We performed the sequencing and analysis of the three ORFV molecular markers: B2L gene, virus interferon resistance gene (VIR) and the vascular endothelial growth factor gene. Nucleotide and amino acid analysis of the analysed genes demonstrated that Brazilian ORFVs do not form a unique cluster, and presented more similarity to other worldwide ORFV samples than with each other. These data raise the questions of whether there are different worldwide ORFVs circulating in Brazil, or if all the Brazilian ORFV samples are of the same virus taken at distinct time points.

Sequence analysis of topoisomerase gene of pseudocowpox virus isolates from camels (Camelus dromedarius)

Topoisomerase gene of pseudocowposvirus from Indian dromedarian camel was amplified by PCR using the primers of PCPV from Finnish reindeer and cloned into pGEM-T for sequence analysis. Analysis of amino acid identity revealed that Indian PCPV of camel shared 95.9-96.8 with PCPV of reindeer, 96.2-96.5 with ORFV and 87.5 with BPSV.

Molecular and virological studies on contagious pustular dermatitis isolates from Egyptian sheep and goats

Orf virus was clinically diagnosed from different field cases of sheep and goat in Hawamdia, Giza, Egypt during the summer 2006. Skin scabs were collected and used for virus isolation, electron microscopy, PCR and sequencing for confirmation, and differential diagnosis. The aetiological virus was fruitfully isolated on the chorio-allantoic membrane of SPF embryonated chicken eggs indicated by expressing the characteristic pock lesions of Poxviridae family. Electron microscopy examination exposed negatively stained oval-shape virus particles trait for members of the genus Parapoxvirus. A 392 bp fragment of the late transcription factor (VLTF-1) gene of orf virus was amplified by PCR from the DNA extracted from the isolates. Phylogenetic analysis revealed 99% identity with other orf virus strains reported worldwide. Selection and processing of clinical specimens and PCR assay applied in this endeavor, presented a reliable laboratory diagnostic tool for orf infections and first molecular characterization of Egyptian orf isolates.

Detection and phylogenetic analysis of Orf virus from sheep in Brazil: a case report

Background

Orf virus (ORFV), the prototype of the genus Parapoxvirus (PPV), is the etiological agent of contagious ecthyma, a severe exanthematic dermatitis that afflicts domestic and wild small ruminants. Although South American ORFV outbreaks have occurred and diagnosed there are no South American PPV major membrane glycoprotein B2L gene nucleotide sequences available.

Case presentation

an outbreak of ovine contagious ecthyma in Midwest Brazil was investigated. The diagnosis was based on clinical examinations and molecular biology techniques. The molecular characterization of the virus was done using PCR amplification, cloning and DNA sequencing of the B2L gene. The phylogenetic analysis demonstrated a high degree of identity with ORFV strains, and the isolate was closest to the ORFV-India 82/04 isolate. Another Brazilian ORFV isolate, NE1, was sequenced for comparative analysis and also showed a high degree of identity with an Asian ORFV strain.

Conclusion

Distinct ORFV strains are circulating in Brazil. This is the first report on the phylogenetic analysis of an ORFV in South America.

Differential diagnosis of orf viruses by a single-step PCR

The complete nucleotide sequence of the A32L gene (named after vaccinia virus, corresponding with open reading frame 108 of the orf virus and encoding an ATPase) of the orf virus was studied using samples of orf virus from infected goats, which were collected from six outbreaks in central Taiwan. DNA sequence analysis of the A32L genes of these and isolates from other countries showed sequence heterogeneity (base pair variation and deletion) in the 3'-terminal regions. This finding led to the development of a polymerase chain reaction (PCR) method for the rapid differential diagnosis of orf virus infections, and the results demonstrated that this was an easy and reliable method for genotyping of orf viruses.

Natural human infections with Vaccinia virus during bovine vaccinia outbreaks

BACKGROUND

Bovine vaccinia is an exanthematic disease caused by Vaccinia virus (VACV). This zoonosis has been associated with several cases of bovine infection, particularly in milk herds. Farmers, milkers and their close contacts developed lesions on the hands, forearms, legs and face accompanied by fever, headache, malaise, myalgia and axillary, inguinal and cervical lymphadenopathy. VACV infections have a significant public health impact due to their occupational character, high frequency of transmission and the improper medical treatment often applied.

OBJECTIVES

To study natural human infection by VACV and to analyze clinical and epidemiological aspects, emphasizing the patients' immunological status.

STUDY DESIGN

Ninety-eight individuals from rural properties with bovine vaccinia (BV) outbreaks who were at risk due to contact were submitted to epidemiological and clinical studies. From these individuals, 54 sera were analyzed by serological and molecular procedures. This study was conducted in Rio de Janeiro State from September 2002 to October 2006.

RESULTS

The clinical frequency of infection was 52.0%, with 57.4% ELISA and 43.0% PRNT-positive reactions. DNAemia was detected in 18.5% of the analyzed sera, and 50% of smallpox-vaccinated individuals developed symptoms.

CONCLUSIONS

This study confirms the high clinical frequency of human VACV infection, even among vaccinated individuals. The infection was related to detection of IgG- or IgM-specific antibodies that correlates in most of the cases with positive PRNT. The DNAemia suggests viremia during VACV natural infections. Our data indicate that patients vaccinated against smallpox may no longer be protected.

Isolation and Characterization of an Indian Orf Virus from Goats

Isolation and characterization of an orf virus has been described here. The virus was isolated from an outbreak of 'scabby mouth' in goats in Northern India. Viral morphology from the scab biopsy revealed typical ovoid-shaped particles characteristic of Parapoxvirus. Virus was isolated from sonicated scab suspension and characterized by restriction enzyme (RE) analysis and sequencing of full-length GM-CSF- and interleukin-2 inhibitory factor (GIF) gene. RE pattern of the virus did not show close resemblance to most of the orf viruses published earlier. However, it showed high sequence identity and closer phylogenetic relationship with previously published ORFV-SA00 strain, as evident from the nucleotide and deduced amino acid sequence of GIF gene.

Real-time PCR detection of parapoxvirus DNA

BACKGROUND

Detection of parapoxviruses is important in various animals as well as in humans as zoonotic infections. Reliable detection of parapoxviruses is fundamental for the exclusion of other rash-causing illnesses, for both veterinarians and medical practitioners. To date, however, no real-time PCR assay for the detection of parapoxviruses has been reported.

METHODS

A minor groove binder-based quantitative real-time PCR assay targeting the B2L gene of parapoxviruses was developed on the ABI Prism and the LightCycler platforms.

RESULTS

The real-time PCR assay successfully amplified DNA fragments from a total of 41 parapoxvirus strains and isolates representing the species orf virus, bovine papular stomatitis virus, pseudocowpoxvirus, and sealpoxvirus. Probit analysis gave a limit of detection of 4.7 copies per assay (95% confidence interval, 3.7-6.8 copies per reaction). Scabs contain a sufficient amount of parapoxvirus DNA and can therefore be used for PCR without any DNA preparation step. No cross-reactivity to human, bovine, or sheep genomic DNA or other DNA viruses, including orthopoxviruses, molluscum contagiosum viruses, and yaba-like disease viruses, was observed.

CONCLUSION

The presented assay is suitable for the detection of parapoxvirus infections in clinical material of human and animal origin.

Laboratory diagnosis of contagious ecthyma: comparison of different PCR protocols with virus isolation in cell culture

A new polymerase chain reaction (PCR) assay for rapid diagnosis of contagious ecthyma was designed and applied to 21 clinical samples from Greece. This assay, which detects a highly conserved gene from the parapox genome, was evaluated for its sensitivity and specificity in order to be considered as a useful diagnostic tool. A comparative study with two published PCR protocols one using primers PPP1-PPP3, PPP1-PPP4 which targets putative virion envelope gene B2L and the other using VIR1-VIR2 primers which amplifies ORF virus interferon resistant (VIR) gene, as well as cell culture virus neutralization assay was carried out. All samples tested were amplified successfully with the PCR protocol established in the laboratory. The combination of primers PPP1-PPP3 and PPP1-PPP4 in a semi-nested PCR gave a positive result in 20 of 21 samples while primers VIR1-VIR2 failed to amplify successfully 7 of 21 samples. The diagnostic value of parapox viral DNA amplification was also compared with the results of virus isolation by cell culture and was positive in three samples that the virus isolation was obtained.

Surto de varíola bovina causada pelo vírus Vaccinia na região da Zona da Mata Mineira

Relata-se um surto de doença exantemática, caracterizada como varíola bovina, acometendo bovinos e seres humanos na Zona da Mata Mineira. Setenta e duas propriedades, distribuídas em 20 municípios localizados na região, foram visitadas para se levantar os aspectos clínicos e epidemiológicos da doença. Detectaram-se 1020 vacas doentes durante a investigação, quando houve queda na produção do leite associada a infecções bacterianas secundárias. Casos humanos foram registrados em 83% das propriedades visitadas. Espécimes clínicos e amostras de soro foram coletados dos animais doentes ou convalescentes. O diagnóstico de laboratório mostrou o envolvimento de um ortopoxvírus, precisamente o Vaccinia virus como agente etiológico do surto.

Characterization of a North American orf virus isolated from a goat with persistent, proliferative dermatitis

The characterization of an orf virus (OV) isolated from skin lesions of a goat kid with severe, persistent, proliferative dermatitis, and designated orf virus-San Angelo 2000 (OV-SA00) strain, is described. The identity of OV-SA00 was confirmed by a combination of methods, including electron microscopy, amplification of specific fragments of viral DNA by polymerase chain reaction, restriction enzyme analysis of viral DNA and gene sequencing. Restriction endonuclease analyses of viral DNA and the protein profile studied by Western blot revealed differences between OV-SA00 strain and the profiles of other OV strains that have been published. The restriction enzyme profile of OV-SA00 was also different from the orf virus vaccine (OV-V) strain used to vaccinate this kid. Comparison of the nucleotide and deduced amino acid sequences indicated that OV-SA00 is closely related to OV-V strain, the Scottish OV strains orf11 and MRI Scab, and the human OV-CE/Shoe strain and more distant to bovine papular stomatitis virus (BPSV) reference strain and the pseudocowpox virus (PCPV)-MNV/Till strain. These results indicate that OV-SA00 is a strain of OV rather than a different parapoxvirus. Further studies are necessary to determine if the severity of orf-induced lesions in this goat kid was the result of individual host susceptibility factors.

Araçatuba virus: a vaccinialike virus associated with infection in humans and cattle

We describe a vaccinialike virus, Araçatuba virus, associated with a cowpoxlike outbreak in a dairy herd and a related case of human infection. Diagnosis was based on virus growth characteristics, electron microscopy, and molecular biology techniques. Molecular characterization of the virus was done by using polymerase chain reaction amplification, cloning, and DNA sequencing of conserved orthopoxvirus genes such as the vaccinia growth factor (VGF), thymidine kinase (TK), and hemagglutinin. We used VGF-homologous and TK gene nucleotide sequences to construct a phylogenetic tree for comparison with other poxviruses. Gene sequences showed 99% homology with vaccinia virus genes and were clustered together with the isolated virus in the phylogenetic tree. Araçatuba virus is very similar to Cantagalo virus, showing the same signature deletion in the gene. Araçatuba virus could be a novel vaccinialike virus or could represent the spread of Cantagalo virus.

Characterization of a vaccinia-like virus isolated in a Brazilian forest

The SPAn232 virus (SPAnv) was isolated from sentinel mice in the forest of Cotia, São Paulo, Brazil. It was grouped originally as a Cotia virus (CV) sample due to serological cross-reaction with the latter. However, SPAnv presented genetic characteristics that differed from CV and indicated that SPAnv is a member of the vaccinia virus (VV) subgroup. SPAnv showed a HindIII-digested DNA pattern similar to those of the WR and Lister strains of VV. Also, SPAnv presented genes homologous to the vaccinia growth factor, thymidine kinase and A-type inclusion (ATI) genes from VV. RFLP analysis of the SPAnv ATI homologous gene indicated that the virus belongs to the VV group. Nucleotide sequences from SPAnv genes showed up to 99% similarity with the same genes from VV. Such a relationship was confirmed visually through the drawing of phylogenetic trees. The results point out the occurrence of a VV strain that is possibly in active circulation in the forests of Southeast Brazil.