An EIAV field isolate reveals much higher levels of subtype variability than currently reported for the equine lentivirus family

<p>Abstract</p> <p>Background</p> <p>Equine infectious anemia virus (EIAV), a lentivirus that infects horses, has been utilized as an animal model for the study of HIV. Furthermore, the disease associated with the equine lentivirus poses a significant challenge to veterinary medicine around the world. As with all lentiviruses, EIAV has been shown to have a high propensity for genomic sequence and antigenic variation, especially in its envelope (Env) proteins. Recent studies have demonstrated Env variation to be a major determinant of vaccine efficacy, emphasizing the importance of defining natural variation among field isolates of EIAV. To date, however, published EIAV sequences have been reported only for cell-adapted strains of virus, predominantly derived from a single primary virus isolate, EIAV_Wyoming(EIAV_WY).</p> <p>Results</p> <p>We present here the first characterization of the Env protein of a natural primary isolate from Pennsylvania (EIAV_PA) since the widely utilized and referenced EIAV_WYstrain. The data demonstrated that the level of EIAV_PAEnv amino acid sequence variation, approximately 40% as compared to EIAV_WY, is much greater than current perceptions or published reports of natural EIAV variation between field isolates. This variation did not appear to give rise to changes in the predicted secondary structure of the proteins. While the EIAV_PAEnv was serologically cross reactive with the Env proteins of the cell-adapted reference strain, EIAV_PV(derivative of EIAV_WY), the two variant Envs were shown to lack any cross neutralization by immune serum from horses infected with the respective virus strains.</p> <p>Conclusion</p> <p>Taking into account the significance of serum neutralization to universal vaccine efficacy, these findings are crucial considerations towards successful EIAV vaccine development and the potential inclusion of field isolate Envs in vaccine candidates.</p

'Divided they stand, divided they fail': opposition politics in Morocco

The literature on democratization emphasises how authoritarian constraints usually lead genuine opposition parties and movements to form alliances in order to make demands for reform to the authoritarian regime. There is significant empirical evidence to support this theoretical point. While this trend is partly visible in the Middle East and North Africa, such coalitions are usually short-lived and limited to a single issue, never reaching the stage of formal and organic alliances. This article, using the case of Morocco, seeks to explain this puzzle by focusing on ideological and strategic differences that exist between the Islamist and the secular/liberal sectors of civil society, where significant opposition politics occurs. In addition, this article also aims to explain how pro-democracy strategies of the European Union further widen this divide, functioning as a key obstacle to democratic reforms

Malaria parasites (Plasmodium spp.) infecting introduced, native and endemic New Zealand birds

Avian malaria is caused by intracellular mosquito-transmitted protist parasites in the order Haemosporida, genus Plasmodium. Although Plasmodium species have been diagnosed as causing death in several threatened species in New Zealand, little is known about their ecology and epidemiology. In this study, we examined the presence, microscopic characterization and sequence homology of Plasmodium spp. isolates collected from a small number of New Zealand introduced, native and endemic bird species. We identified 14 Plasmodium spp. isolates from 90 blood or tissue samples. The host range included four species of passerines (two endemic, one native, one introduced), one species of endemic pigeon and two species of endemic kiwi. The isolates were associated into at least four distinct clusters including Plasmodium (Huffia) elongatum, a subgroup of Plasmodium elongatum, Plasmodium relictum and Plasmodium (Noyvella) spp. The infected birds presented a low level of peripheral parasitemia consistent with chronic infection (11/15 blood smears examined). In addition, we report death due to overwhelming parasitemia in a blackbird, a great spotted kiwi and a hihi. These deaths were attributed to infections with either Plasmodium spp. lineage LINN1 or P. relictum lineage GRW4. To the authors’ knowledge, this is the first published report of Plasmodium spp. infection in great spotted and brown kiwi, kereru and kokako. Currently, we are only able to speculate on the origin of these 14 isolates but consideration must be made as to the impact they may have on threatened endemic species, particularly due to the examples of mortality

Identification of novel Theileria genotypes from Grant's gazelle

Blood samples collected from Grant's gazelles (Nanger granti) in Kenya were screened for hemoparasites using a combination of microscopic and molecular techniques. All 69 blood smears examined by microscopy were positive for hemoparasites. In addition, Theileria/Babesia DNA was detected in all 65 samples screened by PCR for a ~450-base pair fragment of the V4 hypervariable region of the 18S rRNA gene. Sequencing and BLAST analysis of a subset of PCR amplicons revealed widespread co-infection (25/39) and the existence of two distinct Grant's gazelle Theileria subgroups. One group of 11 isolates clustered as a subgroup with previously identified Theileria ovis isolates from small ruminants from Europe, Asia and Africa; another group of 3 isolates clustered with previously identified Theileria spp. isolates from other African antelope. Based on extensive levels of sequence divergence (1.2–2%) from previously reported Theileria species within Kenya and worldwide, the Theileria isolates detected in Grant's gazelles appear to represent at least two novel Theileria genotypes

The Pathology of Fatal Avian Malaria Due to <i>Plasmodium elongatum</i> (GRW6) and <i>Plasmodium matutinum</i> (LINN1) Infection in New Zealand Kiwi (<i>Apteryx</i> spp.)

Avian malaria caused by Plasmodium species is a known cause of mortality in avifauna worldwide, however reports within New Zealand kiwi (Apteryx spp.) are scant. Postmortem reports from kiwi were obtained from the Massey University/Te Kunenga ki Pūrehuroa School of Veterinary Science Pathology Register from August 2010–August 2020. Gross lesions were described from postmortem reports, and archived H.E.-stained slides used for histological assessment. Nested PCR testing was performed on formalin-fixed paraffin-embedded tissue samples to assess the presence of Plasmodium spp. and Toxoplasma gondii DNA and cases with a PCR-positive result were sequenced to determine the lineage involved. Of 1005 postmortem reports, 23 cases of confirmed or suspected avian malaria were included in this study. The most consistent gross lesions included splenomegaly, hepatomegaly, and interstitial pneumonia with oedema. Histological lesions were characterised by severe interstitial pneumonia, pulmonary oedema, interstitial myocarditis, hepatic sinusoidal congestion and hypercellularity, and splenic macrophage hyperplasia and hyperaemia/congestion with numerous haemosiderophages. Cytoplasmic meronts were consistently found within endothelial cells of a variety of tissues, and within tissue macrophages of the liver, lung and spleen. A diagnosis of avian malaria was confirmed via PCR testing in 13 cases, with sequencing revealing P. matutinum (LINN1) and P. elongatum (GRW6) as the species involved. This is the largest case series describing the pathology of avian malaria as a cause of mortality in endemic New Zealand avifauna

Equine Infectious Anemia Virus Envelope Evolution In Vivo during Persistent Infection Progressively Increases Resistance to In Vitro Serum Antibody Neutralization as a Dominant Phenotype

Equine infectious anemia virus (EIAV) infection of horses is characterized by well-defined waves of viremia associated with the sequential evolution of distinct viral populations displaying extensive envelope gp90 variation; however, a correlation of in vivo envelope evolution with in vitro serum neutralization phenotype remains undefined. Therefore, the goal of the present study was to utilize a previously defined panel of natural variant EIAV envelope isolates from sequential febrile episodes to characterize the effects of envelope variation during persistent infection on viral neutralization phenotypes and to define the determinants of EIAV envelope neutralization specificity. To assess the neutralization phenotypes of the sequential EIAV envelope variants, we determined the sensitivity of five variant envelopes to neutralization by a longitudinal panel of immune serum from the source infected pony. The results indicated that the evolution of the EIAV envelope sequences observed during sequential febrile episodes produced an increasingly neutralization-resistant phenotype. To further define the envelope determinants of EIAV neutralization specificity, we examined the neutralization properties of a panel of chimeric envelope constructs derived from reciprocal envelope domain exchanges between selected neutralization-sensitive and neutralization-resistant envelope variants. These results indicated that the EIAV gp90 V3 and V4 domains individually conferred serum neutralization resistance while other envelope segments in addition to V3 and V4 were evidently required for conferring total serum neutralization sensitivity. These data clearly demonstrate for the first time the influence of sequential gp90 variation during persistent infection in increasing envelope neutralization resistance, identify the gp90 V3 and V4 domains as the principal determinants of antibody neutralization resistance, and indicate distinct complex cooperative envelope domain interactions in defining sensitivity to serum antibody neutralization

Detection of papillomaviral sequences in feline Bowenoid\ud in situ carcinoma using consensus primers

Feline Bowenoid in situ carcinoma (BISC) is a rare disease that presents as multiple discrete plaques of epidermal hyperplasia and dysplasia. Two studies using immunohistochemistry revealed papillomaviral antigens in 11% and 47% of BISCs. Additionally, a recent study detected papillomaviral DNA in 24% of BISC lesions. To further investigate the association between papillomaviruses and BISC, polymerase chain reaction using consensus primers was used to detect papillomaviral DNA in 18 formalin-fixed samples of BISC. Papillomaviral DNA was amplified from 11 of the samples but from none of the controls. Six amplicons were sequenced; one was homologous with a papillomavirus from a human patient with multiple cutaneous squamous cell carcinomas and the other five showed weak homology to human papillomavirus type 17. These five sequences were > 96% homologous over a 235 bp sequence, indicating the presence in all five BISCs of one papillomavirus type distinct from any previously sequenced and more closely related to human than animal papillomaviruses. The results confirm an association between BISC and papillomaviruses, and as all six papillomavirus sequences identified are closely related to human papillomaviruses, it is possible that the virus is transmitted from humans to cats or vice versa

A Live Attenuated Equine Infectious Anemia Virus Proviral Vaccine with a Modified S2 Gene Provides Protection from Detectable Infection by Intravenous Virulent Virus Challenge of Experimentally Inoculated Horses

Previous evaluations of inactivated whole-virus and envelope subunit vaccines to equine infectious anemia virus (EIAV) have revealed a broad spectrum of efficacy ranging from highly type-specific protection to severe enhancement of viral replication and disease in experimentally immunized equids. Among experimental animal lentivirus vaccines, immunizations with live attenuated viral strains have proven most effective, but the vaccine efficacy has been shown to be highly dependent on the nature and severity of the vaccine virus attenuation. We describe here for the first time the characterization of an experimental attenuated proviral vaccine, EIAV(UK)ΔS2, based on inactivation of the S2 accessory gene to down regulate in vivo replication without affecting in vitro growth properties. The results of these studies demonstrated that immunization with EIAV(UK)ΔS2 elicited mature virus-specific immune responses by 6 months and that this vaccine immunity provided protection from disease and detectable infection by intravenous challenge with a reference virulent biological clone, EIAV(PV). This level of protection was observed in each of the six experimental horses challenged with the reference virulent EIAV(PV) by using a low-dose multiple-exposure protocol (three administrations of 10 median horse infectious doses [HID(50)], intravenous) designed to mimic field exposures and in all three experimentally immunized ponies challenged intravenously with a single inoculation of 3,000 HID(50). In contrast, naïve equids subjected to the low- or high-dose challenge develop a detectable infection of challenge virus and acute disease within several weeks. Thus, these data demonstrate that the EIAV S2 gene provides an optimal site for modification to achieve the necessary balance between attenuation to suppress virulence and replication potential to sufficiently drive host immune responses to produce vaccine immunity to viral exposure

Discerning an Effective Balance between Equine Infectious Anemia Virus Attenuation and Vaccine Efficacy

Among the diverse experimental vaccines evaluated in various animal lentivirus models, live attenuated vaccines have proven to be the most effective, thus providing an important model for examining critical immune correlates of protective vaccine immunity. We previously reported that an experimental live attenuated vaccine for equine infectious anemia virus (EIAV), based on mutation of the viral S2 accessory gene, elicited protection from detectable infection by virulent virus challenge (F. Li et al., J. Virol. 77:7244-7253, 2003). To better understand the critical components of EIAV vaccine efficacy, we examine here the relationship between the extent of virus attenuation, the maturation of host immune responses, and vaccine efficacy in a comparative study of three related attenuated EIAV proviral vaccine strains: the previously described EIAV(UK)ΔS2 derived from a virulent proviral clone, EIAV(UK)ΔS2/DU containing a second gene mutation in the virulent proviral clone, and EIAV(PR)ΔS2 derived from a reference avirulent proviral clone. Inoculations of parallel groups of eight horses resulted in relatively low levels of viral replication (average of 10(2) to 10(3) RNA copies/ml) and a similar maturation of EIAV envelope-specific antibody responses as determined in quantitative and qualitative serological assays. However, experimental challenge of the experimentally immunized horses by our standard virulent EIAV(PV) strain by using a low-dose multiple exposure protocol (three inoculations with 10 median horse infective doses, administered intravenously) revealed a marked difference in the protective efficacy of the various attenuated proviral vaccine strains that was evidently associated with the extent of vaccine virus attenuation, time of viral challenge, and the apparent maturation of virus-specific immunity