A cocktail of human monoclonal antibodies broadly neutralizes North American rabies virus variants as a promising candidate for rabies post-exposure prophylaxis.

Human rabies remains a globally significant public health problem. Replacement of polyclonal anti-rabies immunoglobulin (RIG), a passive component of rabies post-exposure prophylaxis (PEP), with a monoclonal antibody (MAb), would eliminate the cost and availability constraints associated with RIG. Our team has developed and licensed a human monoclonal antibody RAB1 (Rabishield©), as the replacement for RIG where canine rabies is enzootic. However, for the highly diverse rabies viruses of North America, a cocktail containing two or more MAbs targeting different antigenic sites of the rabies glycoprotein should be included to ensure neutralization of all variants of the virus. In this study, two MAb cocktails, R172 (RAB1-RAB2) and R173 (RAB1-CR57), were identified and evaluated against a broad range of rabies variants from North America. R173 was found to be the most potent cocktail, as it neutralized all the tested North American RABV isolates and demonstrated broad coverage of isolates from both terrestrial and bat species. R173 could be a promising candidate as an alternative or replacement for RIG PEP in North America.

Transmission of SARS-CoV-2 Delta variant (B.1.617.2) from a fully vaccinated human to a canine in Georgia, July 2021.

SARS-CoV-2 infection has been described in a wide range of species, including domestic animals such as dogs and cats. Illness in dogs is usually self-limiting, and further diagnostics may not be pursued if clinical signs resolve or they respond to empirical treatment. As new variants emerge, the clinical presentation and role in transmission may vary in animals. This report highlights different clinical presentations and immunological responses in two SARS-CoV-2 Delta-variant-positive dogs with similar exposure to the same fully vaccinated human with a SARS-CoV-2 infection and emphasizes the need for active surveillance and additional One Health research on SARS-CoV-2 variant infections in companion animals and other species.

Teaching a new mouse old tricks: Humanized mice as an infection model for Variola virus.

Smallpox, caused by the solely human pathogen Variola virus (VARV), was declared eradicated in 1980. While known VARV stocks are secure, smallpox remains a bioterrorist threat agent. Recent U.S. Food and Drug Administration approval of the first smallpox anti-viral (tecovirimat) therapeutic was a successful step forward in smallpox preparedness; however, orthopoxviruses can become resistant to treatment, suggesting a multi-therapeutic approach is necessary. Animal models are required for testing medical countermeasures (MCMs) and ideally MCMs are tested directly against the pathogen of interest. Since VARV only infects humans, a representative animal model for testing therapeutics directly against VARV remains a challenge. Here we show that three different humanized mice strains are highly susceptible to VARV infection, establishing the first small animal model using VARV. In comparison, the non-humanized, immunosuppressed background mouse was not susceptible to systemic VARV infection. Following an intranasal VARV challenge that mimics the natural route for human smallpox transmission, the virus spread systemically within the humanized mouse before mortality (~ 13 days post infection), similar to the time from exposure to symptom onset for ordinary human smallpox. Our identification of a permissive/representative VARV animal model can facilitate testing of MCMs in a manner consistent with their intended use.

Pharmacokinetics and Efficacy of a Potential Smallpox Therapeutic, Brincidofovir, in a Lethal Monkeypox Virus Animal Model.

Smallpox, caused by Variola virus (VARV), was eradicated in 1980; however, VARV bioterrorist threats still exist, necessitating readily available therapeutics. Current preparedness activities recognize the importance of oral antivirals and recommend therapeutics with different mechanisms of action. Monkeypox virus (MPXV) is closely related to VARV, causing a highly similar clinical human disease, and can be used as a surrogate for smallpox antiviral testing. The prairie dog MPXV model has been characterized and used to study the efficacy of antipoxvirus therapeutics, including recently approved TPOXX (tecovirimat). Brincidofovir (BCV; CMX001) has shown antiviral activity against double-stranded DNA viruses, including poxviruses. To determine the exposure of BCV following oral administration to prairie dogs, a pharmacokinetics (PK) study was performed. Analysis of BCV plasma concentrations indicated variability, conceivably due to the outbred nature of the animals. To determine BCV efficacy in the MPXV prairie dog model, groups of animals were intranasally challenged with 9 × 105 plaque-forming units (PFU; 90% lethal dose [LD90]) of MPXV on inoculation day 0 (ID0). Animals were divided into groups based on the first day of BCV treatment relative to inoculation day (ID-1, ID0, or ID1). A trend in efficacy was noted dependent upon treatment initiation (57% on ID-1, 43% on ID0, and 29% on ID1) but was lower than demonstrated in other animal models. Analysis of the PK data indicated that BCV plasma exposure (maximum concentration [Cmax]) and the time of the last quantifiable concentration (AUClast) were lower than in other animal models administered the same doses, indicating that suboptimal BCV exposure may explain the lower protective effect on survival.IMPORTANCE Preparedness activities against highly transmissible viruses with high mortality rates have been highlighted during the ongoing coronavirus disease 2019 (COVID-19) pandemic. Smallpox, caused by variola virus (VARV) infection, is highly transmissible, with an estimated 30% mortality. Through an intensive vaccination campaign, smallpox was declared eradicated in 1980, and routine smallpox vaccination of individuals ceased. Today's current population has little/no immunity against VARV. If smallpox were to reemerge, the worldwide results would be devastating. Recent FDA approval of one smallpox antiviral (tecovirimat) was a successful step in biothreat preparedness; however, orthopoxviruses can become resistant to treatment, suggesting the need for multiple therapeutics. Our paper details the efficacy of the investigational smallpox drug brincidofovir in a monkeypox virus (MPXV) animal model. Since brincidofovir has not been tested in vivo against smallpox, studies with the related virus MPXV are critical in understanding whether it would be protective in the event of a smallpox outbreak.

Laboratory Infection of Novel Akhmeta Virus in CAST/EiJ Mice.

Akhmeta virus is a zoonotic Orthopoxvirus first identified in 2013 in the country of Georgia. Subsequent ecological investigations in Georgia have found evidence that this virus is widespread in its geographic distribution within the country and in its host-range, with rodents likely involved in its circulation in the wild. Yet, little is known about the pathogenicity of this virus in rodents. We conducted the first laboratory infection of Akhmeta virus in CAST/EiJ Mus musculus to further characterize this novel virus. We found a dose-dependent effect on mortality and weight loss (p < 0.05). Anti-orthopoxvirus antibodies were detected in the second- and third-highest dose groups (5 × 104 pfu and 3 × 102 pfu) at euthanasia by day 10, and day 14 post-infection, respectively. Anti-orthopoxvirus antibodies were not detected in the highest dose group (3 × 106 pfu), which were euthanized at day 7 post-infection and had high viral load in tissues, suggesting they succumbed to disease prior to mounting an effective immune response. In order of highest burden, viable virus was detected in the nostril, lung, tail, liver and spleen. All individuals tested in the highest dose groups were DNAemic. Akhmeta virus was highly pathogenic in CAST/EiJ Mus musculus, causing 100% mortality when ≥3 × 102 pfu was administered.

IMVAMUNE® and ACAM2000® Provide Different Protection against Disease When Administered Postexposure in an Intranasal Monkeypox Challenge Prairie Dog Model.

The protection provided by smallpox vaccines when used after exposure to Orthopoxviruses is poorly understood. Postexposu re administration of 1st generation smallpox vaccines was effective during eradication. However, historical epidemiological reports and animal studies on postexposure vaccination are difficult to extrapolate to today's populations, and 2nd and 3rd generation vaccines, developed after eradication, have not been widely tested in postexposure vaccination scenarios. In addition to concerns about preparedness for a potential malevolent reintroduction of variola virus, humans are becoming increasingly exposed to naturally occurring zoonotic orthopoxviruses and, following these exposures, disease severity is worse in individuals who never received smallpox vaccination. This study investigated whether postexposure vaccination of prairie dogs with 2nd and 3rd generation smallpox vaccines was protective against monkeypox disease in four exposure scenarios. We infected animals with monkeypox virus at doses of 104 pfu (2× LD50) or 106 pfu (170× LD50) and vaccinated the animals with IMVAMUNE® or ACAM2000® either 1 or 3 days after challenge. Our results indicated that postexposure vaccination protected the animals to some degree from the 2× LD50, but not the 170× LD5 challenge. In the 2× LD50 challenge, we also observed that administration of vaccine at 1 day was more effective than administration at 3 days postexposure for IMVAMUNE®, but ACAM2000® was similarly effective at either postexposure vaccination time-point. The effects of postexposure vaccination and correlations with survival of total and neutralizing antibody responses, protein targets, take formation, weight loss, rash burden, and viral DNA are also presented.

Magnitude and diversity of immune response to vaccinia virus is dependent on route of administration.

Historic observations suggest that survivors of smallpox maintained lifelong immunity and protection to subsequent infection compared to vaccinated individuals. Although protective immunity by vaccination using a related virus (vaccinia virus (VACV) strains) was the key for smallpox eradication, it does not uniformly provide long term, or lifelong protective immunity (Heiner et al., 1971). To determine differences in humoral immune responses, mice were inoculated with VACV either systemically, using intranasal inoculation (IN), or locally by an intradermal (ID) route. We hypothesized that sub-lethal IN infections may mimic systemic or naturally occurring infection and lead to an immunodominance reaction, in contrast to localized ID immunization. The results demonstrated systemic immunization through an IN route led to enhanced adaptive immunity to VACV-expressed protein targets both in magnitude and in diversity when compared to an ID route using a VACV protein microarray. In addition, cytokine responses, assessed using a Luminex® mouse cytokine multiplex kit, following IN infection was greater than that stemming from ID infection. Overall, the results suggest that the route of immunization (or infection) influences antibody responses. The greater magnitude and diversity of response in systemic infection provides indirect evidence for anecdotal observations made during the smallpox era that survivors maintain lifelong protection. These findings also suggest that systemic or disseminated host immune induction may result in a superior response, that may influence the magnitude of, as well as duration of protective responses.

Pharmacokinetic Profiles of Gabapentin after Oral and Subcutaneous Administration in Black-tailed Prairie Dogs (Cynomys ludovicianus).

In veterinary and human medicine, gabapentin (a chemical analog of γ-aminobutyric acid) is commonly prescribed to treat postoperative and chronic neuropathic pain. This study explored the pharmacokinetics of oral and subcutaneous administration of gabapentin at high (80 mg/kg) and low (30 mg/kg) doses as a potential analgesic in black-tailed prairie dogs (Cynomys ludovicianus; n = 24). The doses (30 and 80 mg/kg) and half maximal effective concentration (1.4 to 16.7 ng/mL) for this study were extrapolated from pharmacokinetic efficacy studies in rats, rabbits, and cats. Gabapentin in plasma was measured by using an immunoassay, and data were evaluated using noncompartmental analysis. The peak plasma concentrations (mean ±1 SD) were 42.6 ±14.8 and 115.5 ±15.2 ng/mL, respectively, after 30 and 80 mg/kg SC and 14.5 ±3.5 and 20.7 ±6.1 ng/mL after the low and high oral dosages, respectively. All peak plasma concentrations of gabapentin occurred within 5 h of administration. Disappearance half-lives for the low and high oral doses were 7.4 ± 6.0 h and 5.0 ± 0.8 h, respectively. The results of this study demonstrate that oral administration of gabapentin at low (30 mg/kg) doses likely would achieve and maintain plasma concentrations at half maximum effective concentration for 12 h, making it a viable option for an every 12-h treatment.

Antiviral Ranpirnase TMR-001 Inhibits Rabies Virus Release and Cell-to-Cell Infection In Vitro.

Currently, no rabies virus-specific antiviral drugs are available. Ranpirnase has strong antitumor and antiviral properties associated with its ribonuclease activity. TMR-001, a proprietary bulk drug substance solution of ranpirnase, was evaluated against rabies virus in three cell types: mouse neuroblastoma, BSR (baby hamster kidney cells), and bat primary fibroblast cells. When TMR-001 was added to cell monolayers 24 h preinfection, rabies virus release was inhibited for all cell types at three time points postinfection. TMR-001 treatment simultaneous with infection and 24 h postinfection effectively inhibited rabies virus release in the supernatant and cell-to-cell spread with 50% inhibitory concentrations of 0.2-2 nM and 20-600 nM, respectively. TMR-001 was administered at 0.1 mg/kg via intraperitoneal, intramuscular, or intravenous routes to Syrian hamsters beginning 24 h before a lethal rabies virus challenge and continuing once per day for up to 10 days. TMR-001 at this dose, formulation, and route of delivery did not prevent rabies virus transit from the periphery to the central nervous system in this model (n = 32). Further aspects of local controlled delivery of other active formulations or dose concentrations of TMR-001 or ribonuclease analogues should be investigated for this class of drugs as a rabies antiviral therapeutic.

Use of live Variola virus to determine whether CAST/EiJ mice are a suitable surrogate animal model for human smallpox.

Numerous animal models of systemic orthopoxvirus disease have been developed to evaluate therapeutics against variola virus (VARV), the causative agent of smallpox. These animal models do not resemble the disease presentation in human smallpox and most used surrogate Orthopoxviruses. A rodent model using VARV has a multitude of advantages, and previous investigations identified the CAST/EiJ mouse as highly susceptible to monkeypox virus infection, making it of interest to determine if these rodents are also susceptible to VARV infection. In this study, we inoculated CAST/EiJ mice with a range of VARV doses (102-106 plaque forming units). Some animals had detectable viable VARV from the oropharynx between days 3 and 12 post inoculation. Despite evidence of disease, the CAST/EiJ mouse does not provide a model for clinical smallpox due to mild signs of morbidity and limited skin lesions. However, in contrast to previous rodent models using VARV challenge (i.e. prairie dogs and SCID mice), a robust immune response was observed in the CAST/EiJ mice (measured by Immunoglobulin G enzyme-linked immunosorbent assay). This is an advantage of this model for the study of VARV and presents a unique potential for the study of the immunomodulatory pathways following VARV infection.

Inactivated Rabies Virus-Based Ebola Vaccine Preserved by Vaporization Is Heat-Stable and Immunogenic Against Ebola and Protects Against Rabies Challenge.

BACKGROUND: Ebola virus (EBOV) is a highly lethal member of the Filoviridae family associated with human hemorrhagic disease. Despite being a sporadic disease, it caused a large outbreak in 2014-2016 in West Africa and another outbreak recently in the Democratic Republic of Congo. Several vaccine candidates are currently in preclinical and clinical studies but none are stable without cold chain storage. METHODS: We used preservation by vaporization (PBV), a novel processing technology to heat-stabilize FiloRab1 (inactivated rabies-based Ebola vaccine), a candidate Ebola vaccine, and stored the vials at temperatures ranging from 4°C to 50°C for 10 days to 12 months. We immunized Syrian hamsters with the best long-term stable FiloRab1 PBV vaccines and challenged them with rabies virus (RABV). RESULTS: Syrian hamsters immunized with FiloRab1 PBV-processed vaccines stored at temperatures of 4°C and 37°C for 6 months, and at 50°C for 2 weeks, seroconverted against both RABV-G and EBOV-GP. Notably, all of the FiloRab1 PBV vaccines proved to be 100% effective in a RABV challenge model. CONCLUSIONS: We successfully demonstrated that the FiloRab1 PBV vaccines are stable and efficacious for up to 6 months when stored at temperatures ranging from 4°C to 37°C and for up to 2 weeks at 50°C.

Inactivated Rabies Virus-Vectored Immunocontraceptive Vaccine in a Thermo-Responsive Hydrogel Induces High and Persistent Antibodies against Rabies, but Insufficient Antibodies against Gonadotropin-Releasing Hormone for Contraception.

Rabies is preventable through vaccination, but the need to mount annual canine vaccination campaigns presents major challenges in rabies control and prevention. The development of a rabies vaccine that ensures lifelong immunity and animal population management in one dose could be extremely advantageous. A nonsurgical alternative to spay/neuter is a high priority for animal welfare, but irreversible infertility in one dose has not been achieved. Towards this goal, we developed a rabies virus-vectored immunocontraceptive vaccine ERA-2GnRH, which protected against rabies virus challenge and induced >80% infertility in mice after three doses in a live, liquid-vaccine formulation (Wu et al., 2014). To improve safety and use, we formulated an inactivated vaccine in a thermo-responsive chitosan hydrogel for one-dose delivery and studied the immune responses in mice. The hydrogel did not cause any injection site reactions, and the killed ERA-2GnRH vaccine induced high and persistent rabies virus neutralizing antibodies (rVNA) in mice. The rVNA in the hydrogel group reached an average of 327.40 IU/mL, more than 200 times higher than the liquid vaccine alone. The Gonadotropin-releasing hormone (GnRH) antibodies were also present and lasted longer in the hydrogel group, but did not prevent fertility in mice, reflecting a possible threshold level of GnRH antibodies for contraception. In conclusion, the hydrogel facilitated a high and long-lasting immunity, and ERA-2GnRH is a promising dual vaccine candidate. Future studies will focus on rabies protection in target species and improving the anti-GnRH response.

Analgesia during Monkeypox Virus Experimental Challenge Studies in Prairie Dogs (Cynomys ludovicianus).

Because human patients with monkeypox virus (MPXV) infection report painful symptoms, it is reasonable to assume that animals infected with MPXV experience some degree of pain. Understanding whether and how analgesics affect MPXV disease progression is crucial when planning in vivo challenge experiments. In the current study, we challenged prairie dogs with a low dose (4 ×10³ pfu) of MPXV and treated with meloxicam (NSAID) or buprenorphine (opioid); control animals did not receive analgesia or received analgesia without MPXV challenge. Subsets of animals from each group were serially euthanized during the course of the study. Disease progression and viral kinetics were similar between groups, but MXPVinfected, meloxicam-treated animals showed increasing trends of morbidity and mortality compared with other groups. Differences between no-analgesia MPXV-infected control animals and MPXV-infected animals treated with buprenorphine were minimal. The findings in the current study allow more informed decisions concerning the use of analgesics during experimental MPXV challenge studies, thereby improving animal welfare. In light of these findings, we have modified our pain scale for this animal model to include the use of buprenorphine for pain relief when warranted after MPXV challenge.

PREVALENCE OF ANTIBODIES TO ORTHOPOXVIRUS IN WILD CARNIVORES OF NORTHWESTERN CHIHUAHUA, MEXICO.

The distribution of orthopoxviruses (OPXVs) across the North American continent is suggested to be widespread in a wide range of mammalian hosts on the basis of serosurveillance studies. To address the question of whether carnivores in northwestern Mexico are exposed to naturally circulating OPXVs, wild carnivores were collected by live trapping within four different habitat types during fall of 2013 and spring of 2014 within the Janos Biosphere Reserve in northwestern Chihuahua, Mexico. A total of 51 blood samples was collected for testing. Anti-OPXV immunoglobulin G enzymelinked immunosorbent assay, western blot, and rapid fluorescent focus inhibition test (RFFIT) assays were conducted. About 47% (24/51) of the carnivores tested were seropositive for anti-OPXV binding antibodies and had presence of immunodominant bands indicative of OPXV infection. All samples tested were negative for rabies virus neutralizing antibodies by RFFIT, suggesting that the OPXV antibodies were due to circulating OPXV, and not from exposure to oral rabies vaccine (vacciniavectored rabies glycoprotein vaccine) bait distributed along the US-Mexico border. Our results indicated that there may be one or more endemic OPXV circulating within six species of carnivores in northwestern Mexico.

Preclinical pharmacokinetic evaluation to facilitate repurposing of tyrosine kinase inhibitors nilotinib and imatinib as antiviral agents.

BACKGROUND: Several tyrosine kinase inhibitors (TKIs) developed as anti-cancer drugs, also have anti-viral activity due to their ability to disrupt productive replication and dissemination in infected cells. Consequently, such drugs are attractive candidates for "repurposing" as anti-viral agents. However, clinical evaluation of therapeutics against infectious agents associated with high mortality, but low or infrequent incidence, is often unfeasible. The United States Food and Drug Administration formulated the "Animal Rule" to facilitate use of validated animal models for conducting anti-viral efficacy studies. METHODS: To enable such efficacy studies of two clinically approved TKIs, nilotinib, and imatinib, we first conducted comprehensive pharmacokinetic (PK) studies in relevant rodent and non-rodent animal models. PK of these agents following intravenous and oral dosing were evaluated in C57BL/6 mice, prairie dogs, guinea pigs and Cynomolgus monkeys. Plasma samples were analyzed using an LC-MS/MS method. Secondarily, we evaluated the utility of allometry-based inter-species scaling derived from previously published data to predict the PK parameters, systemic clearance (CL) and the steady state volume of distribution (Vss) of these two drugs in prairie dogs, an animal model not tested thus far. RESULTS: Marked inter-species variability in PK parameters and resulting oral bioavailability was observed. In general, elimination half-lives of these agents in mice and guinea pigs were much shorter (1-3 h) relative to those in larger species such as prairie dogs and monkeys. The longer nilotinib elimination half-life in prairie dogs (i.v., 6.5 h and oral, 7.5 h), facilitated multiple dosing PK and safety assessment. The allometry-based predicted values of the Vss and CL were within 2.0 and 2.5-fold, respectively, of the observed values. CONCLUSIONS: Our results suggest that prairie dogs and monkeys may be suitable rodent and non-rodent species to perform further efficacy testing of these TKIs against orthopoxvirus infections. The use of rodent models such as C57BL/6 mice and guinea pigs for assessing pre-clinical anti-viral efficacy of these two TKIs may be limited due to short elimination and/or low oral bioavailability. Allometry-based correlations, derived from existing literature data, may provide initial estimates, which may serve as a useful guide for pre-clinical PK studies in untested animal models.

Revisiting rabies virus neutralizing antibodies through infecting BALB/c mice with live rabies virus.

This study investigates the production of rabies virus (RABV) neutralizing antibody after virus infection through a mouse model. The BALB/c mice from different age groups (three, five, seven week old) were intramuscularly inoculated with live rabies virus (TX coyote 323R). Without pre-exposure or post-exposure prophylaxis (PEP), we found there is a decreased fatality with increased age of animals, the mortalities are 60%, 50%, and 30%, respectively. Interestingly, through assay of rapid fluorescent focus inhibition test (RFFIT), direct fluorescent antibody (DFA) and quantitative Polymerase Chain Reaction (qPCR), the results showed that all the animals that succumbed to rabies challenge, except one, developed circulating neutralizing antibodies, and all the healthy animals, except two, did not generate virus neutralizing antibodies (VNA). Our animal study suggests that the induction of VNA was an indicator of infection progression in the central nervous system (CNS) and speculate that RABV neutralizing antibodies did not cross the blood-brain barrier of the CNS for those diseased animals. We hypothesize that early release of viral antigens from damaged nerve tissue might potentially be a benefit for survivors, and we also discuss several other aspects of the interaction of RABV and its neutralizing antibodies.

Retrospective Proteomic Analysis of Serum After Akhmeta Virus Infection: New Suspect Case Identification and Insights Into Poxvirus Humoral Immunity.

Serologic cross-reactivity, a hallmark of orthopoxvirus (OPXV) infection, makes species-specific diagnosis of infection difficult. In this study, we used a variola virus proteome microarray to characterize and differentiate antibody responses to nonvaccinia OPXV infections from smallpox vaccination. The profile of 2 case patients infected with newly discovered OPXV, Akhmeta virus, exhibited antibody responses of greater intensity and broader recognition of viral proteins and includes the B21/22 family glycoproteins not encoded by vaccinia virus strains used as vaccines. An additional case of Akhmeta virus, or nonvaccinia OPXV infection, was identified through community surveillance of individuals with no or uncertain history of vaccination and no recent infection. The results demonstrate the utility of microarrays for high-resolution mapping of antibody response to determine the nature of OPXV exposure.

Assessing Monkeypox Virus Prevalence in Small Mammals at the Human-Animal Interface in the Democratic Republic of the Congo.

During 2012, 2013 and 2015, we collected small mammals within 25 km of the town of Boende in Tshuapa Province, the Democratic Republic of the Congo. The prevalence of monkeypox virus (MPXV) in this area is unknown; however, cases of human infection were previously confirmed near these collection sites. Samples were collected from 353 mammals (rodents, shrews, pangolins, elephant shrews, a potamogale, and a hyrax). Some rodents and shrews were captured from houses where human monkeypox cases have recently been identified, but most were trapped in forests and agricultural areas near villages. Real-time PCR and ELISA were used to assess evidence of MPXV infection and other Orthopoxvirus (OPXV) infections in these small mammals. Seven (2.0%) of these animal samples were found to be anti-orthopoxvirus immunoglobulin G (IgG) antibody positive (six rodents: two Funisciurus spp.; one Graphiurus lorraineus; one Cricetomys emini; one Heliosciurus sp.; one Oenomys hypoxanthus, and one elephant shrew Petrodromus tetradactylus); no individuals were found positive in PCR-based assays. These results suggest that a variety of animals can be infected with OPXVs, and that epidemiology studies and educational campaigns should focus on animals that people are regularly contacting, including larger rodents used as protein sources.

Characterization of Eptesipoxvirus, a novel poxvirus from a microchiropteran bat.

The genome of Eptesipoxvirus (EPTV) is the first poxvirus genome isolated from a microbat. The 176,688 nt sequence, which is believed to encompass the complete coding region of the virus, is 67% A+T and is predicted to encode 191 genes. 11 of these genes have no counterpart in GenBank and are therefore unique to EPTV. The presence of a distantly related ortholog of Vaccinia virus F5L in EPTV uncovered a link with fragmented F5L orthologs in Molluscum contagiosum virus/squirrelpox and clade II viruses. Consistent with the unique position of EPTV approximately mid-point between the orthopoxviruses and the clade II viruses, EPTV has 11 genes that are specific to the orthopoxviruses and 13 genes that are typical, if not exclusive, to the clade II poxviruses. This mosaic nature of EPTV blurs the distinction between the old description of the orthopoxvirus and clade II groups. Genome annotation and characterization failed to find any common virulence genes shared with the other poxvirus isolated from bat (pteropoxvirus); however, EPTV encodes 3 genes that may have been transferred to or from deerpox and squirrelpox viruses; 2 of these, a putative endothelin-like protein and a MHC class I-like protein are likely to have immunomodulatory roles.