Pro-inflammatory feedback loops define immune responses to pathogenic Lentivirus infection.

BACKGROUND: The Lentivirus human immunodeficiency virus (HIV) causes chronic inflammation and AIDS in humans, with variable rates of disease progression between individuals driven by both host and viral factors. Similarly, simian lentiviruses vary in their pathogenicity based on characteristics of both the host species and the virus strain, yet the immune underpinnings that drive differential Lentivirus pathogenicity remain incompletely understood. METHODS: We profile immune responses in a unique model of differential lentiviral pathogenicity where pig-tailed macaques are infected with highly genetically similar variants of SIV that differ in virulence. We apply longitudinal single-cell transcriptomics to this cohort, along with single-cell resolution cell-cell communication techniques, to understand the immune mechanisms underlying lentiviral pathogenicity. RESULTS: Compared to a minimally pathogenic lentiviral variant, infection with a highly pathogenic variant results in a more delayed, broad, and sustained activation of inflammatory pathways, including an extensive global interferon signature. Conversely, individual cells infected with highly pathogenic Lentivirus upregulated fewer interferon-stimulated genes at a lower magnitude, indicating that highly pathogenic Lentivirus has evolved to partially escape from interferon responses. Further, we identify CXCL10 and CXCL16 as important molecular drivers of inflammatory pathways specifically in response to highly pathogenic Lentivirus infection. Immune responses to highly pathogenic Lentivirus infection are characterized by amplifying regulatory circuits of pro-inflammatory cytokines with dense longitudinal connectivity. CONCLUSIONS: Our work presents a model of lentiviral pathogenicity where failures in early viral control mechanisms lead to delayed, sustained, and amplifying pro-inflammatory circuits, which in turn drives disease progression.

Development of in-house ELISA based on recombinant gag proteins of small ruminant lentiviruses isolated from goats in Thailand.

Small ruminant lentiviruses (SRLVs), are grouped in Retroviridae family, remain a significant loss in the small ruminant husbandry. As a result of unavailability of vaccine and effective treatment, the diagnosis plays a crucial role for the control of SRLV infection. However, the major challenge of diagnosis of SRLV infection is the genetic and antigenic variability of the viruses that can lead to a failure in serological detection. This study investigated the circulating strains of the viruses in goats in Thailand and an in-house ELISA was developed. The coding sequences for gag protein were optimized, synthesized, and expressed in Escherichia coli for increasing the sensitivity of ELISA test. A total of 365 serum samples were examined against the recombinant protein in an in-house ELISA. The results showed that the recombinant gag achieves 96.67% sensitivity and 93.18% specificity as compared with the commercially available ELISA test kit.

ATF5-regulated Mitochondrial Unfolded Protein Response Attenuates Neuronal Damage in Epileptic Rat by Reducing Endoplasmic Reticulum Stress Through Mitochondrial ROS.

Endoplasmic reticulum (ER) dysfunction caused by excessive ER stress is a crucial mechanism underlying seizures-induced neuronal injury. Studies have shown that mitochondrial reactive oxygen species (ROS) are closely related to ER stress, and our previous study showed that activating transcription factor 5 (ATF5)-regulated mitochondrial unfolded protein response (mtUPR) modulated mitochondrial ROS generation in a hippocampal neuronal culture model of seizures. However, the effects of ATF5-regulated mtUPR on ER stress and the underlying mechanisms remain uncertain in epilepsy. In this study, ATF5 upregulation by lentivirus infection attenuated seizures-induced neuronal damage and apoptosis in a rat model of pilocarpine-induced epilepsy, whereas ATF5 downregulation by lentivirus infection had the opposite effects. ATF5 upregulation potentiated mtUPR by increasing the expression of mitochondrial chaperone heat shock protein 60 (HSP60) and caseinolytic protease proteolytic subunit (ClpP) and reducing mitochondrial ROS generation in pilocarpine-induced seizures in rats. Additionally, upregulation of ATF5 reduced the expression of glucose-regulated protein 78 (GRP78), protein kinase RNA-like endoplasmic reticulum kinase (PERK), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP), suggesting suppression of ER stress; Moreover, ATF5 upregulation attenuated apoptosis-related proteins such as B-cell lymphoma-2 (BCL2) downregulation, BCL2-associated X (BAX) and cleaved-caspase-3 upregulation. However, ATF5 downregulation exerted the opposite effects. Furthermore, pretreatment with the mitochondria-targeted antioxidant mito-TEMPO attenuated the harmful effects of ATF5 downregulation on ER stress and neuronal apoptosis by reducing mitochondrial ROS generation. Overall, our study suggested that ATF5-regulated mtUPR exerted neuroprotective effects against pilocarpine-induced seizures in rats and the underlying mechanisms might involve mitochondrial ROS-mediated ER stress.

Caprine arthritis encephalitis virus-induced apoptosis associated with brain lesions in naturally infected kids.

Acute demyelinating leucoencephalomyelitis was the most conspicuous microscopic change in the brain and spinal cord of kids infected with caprine arthritis encephalitis virus (CAEV). TUNEL positivity and labelling of anti-bax and anti-caspases-3, -8 and -9 were found in a distinct population of glial cells, mainly at the edges of the demyelinated plaques and perivascular areas and, to a lesser extent, in neurons. Double labelling revealed that most of these apoptotic cells in the demyelinated plaques were astrocytes and a few were oligodendroglia. In contrast, expression of bcl-2, an anti-apoptotic protein, was found mainly in neurons of the brainstem and cerebellum and motor neurons of the spinal cord, but was restricted in glial cells. These results suggest that apoptosis plays an important role in the pathogenesis of CAE demyelinating encephalitis.

Multiplex interrogation of the NK cell signalome reveals global downregulation of CD16 signaling during lentivirus infection through an IL-18/ADAM17-dependent mechanism.

Despite their importance, natural killer (NK) cell responses are frequently dysfunctional during human immunodeficiency virus-1 (HIV-1) and simian immunodeficiency virus (SIV) infections, even irrespective of antiretroviral therapies, with poorly understood underlying mechanisms. NK cell surface receptor modulation in lentivirus infection has been extensively studied, but a deeper interrogation of complex cell signaling is mostly absent, largely due to the absence of any comprehensive NK cell signaling assay. To fill this knowledge gap, we developed a novel multiplex signaling analysis to broadly assess NK cell signaling. Using this assay, we elucidated that NK cells exhibit global signaling reduction from CD16 both in people living with HIV-1 (PLWH) and SIV-infected rhesus macaques. Intriguingly, antiretroviral treatment did not fully restore diminished CD16 signaling in NK cells from PLWH. As a putative mechanism, we demonstrated that NK cells increased surface ADAM17 expression via elevated plasma IL-18 levels during HIV-1 infection, which in turn reduced surface CD16 downregulation. We also illustrated that CD16 expression and signaling can be restored by ADAM17 perturbation. In summary, our multiplex NK cell signaling analysis delineated unique NK cell signaling perturbations specific to lentiviral infections, resulting in their dysfunction. Our analysis also provides mechanisms that will inform the restoration of dysregulated NK cell functions, offering potential insights for the development of new NK cell-based immunotherapeutics for HIV-1 disease.

A negative feedback loop centered on SMAD3 expression in transforming growth factor ß1-induced corneal myofibroblast differentiation.

SMAD3 downregulation is documented in transforming growth factor ß1 (TGF-ß1)-induced corneal fibroblasts differentiation to myofibroblasts ("fibroTOmyoDiff") or corneal wound healing. However, the exact regulatory mechanism of TGF-ß1/SMAD3 pathway in this context remains unclear. Here, we investigated the role and related mechanism of SMAD3 down-regulation in TGF-ß1-induced human corneal fibroTOmyoDiff. By detecting expression changes of SMAD family during this process, we demonstrated that SMAD3 protein expression was dramatically decreased in the process and the decrease occurred mainly in SMAD3 gene transcription. Furthermore, SMAD3 overexpression using lentivirus infection and knockdown using sgRNA lentivirus infection or siRNAs revealed that SMAD3 overexpression enhanced TGF-ß1-induced corneal fibroTOmyoDiff and vice versa. In addition, specific siRNAs and inhibitors targeting particular signaling pathway were used to figure out the intracellular signaling pathway regulating SMAD3, and the result showed that the decease of SMAD3 induced by TGF-ß1 stimulation in human corneal fibroblasts (HCFs) was strikingly prevented by SMAD4 knockdown or p38 signaling inhibitor SB203580 treatment. Collectively, these results demonstrate that, in TGF-ß1 induced corneal fibroTOmyoDiff, down-regulation of SMAD3 expression regulated by SMAD4 and p38 signaling pathways forms a negative feedback loop of TGFß signaling to avoid excessive activation of the signaling, which suggest that SMAD3 may be a key target for corneal fibrosis treatment.

A large-scale study on the seroprevalence of small ruminant lentiviral infection in the Polish goat population.

A large-scale study was carried out in a Polish goat population in 2014-2022 to determine the herd-level (between-herd) and within-herd seroprevalence of small ruminant lentivirus (SRLV) infection. A total of 8354 adult goats (aged >1 year) from 165 herds located in various regions of Poland were serologically tested using a commercial ELISA. One hundred twenty eight herds were randomly selected while 37 were enrolled based on convenience non-random sampling. At least 1 seropositive result was obtained in 103 / 165 herds. For all these herds the probability that they were truly positive (herd-level positive predictive value) was calculated. It was ≥ 90% in 91 seropositive herds and 73% to < 90% in 12 herds in which only 1-4 goats were seropositive (22 goats in total). The seropositive goats in the latter herds were retested using a different commercial ELISA and 14 goats (9 males and 5 females) from 9 herds were confirmed to be seropositive (serial testing). The true herd-level seroprevalence was estimated at 61% (95% confidence interval [CI 95%]: 53%-68%). It differed significantly between herd size classes (p = 0.003): the highest prevalences were found in the medium (51 - 100 adult goats) and large herds (>100 adult goats) - 72% (CI 95%: 56-84%) and 86% (CI 95%: 67%-95%), respectively, while prevalences in very small (≤ 20 adult goats) and small herds (21 - 50 adult goats) were 46% (CI 95%: 34%-59%) and 57% (CI 95%: 43%-70%), respectively. The true herd-level seroprevalence differed significantly also between geographical regions of Poland (p = 0.003), with the highest values in the north-western and the lowest in the southern region of the country. The true within-herd seroprevalence estimated using a Bayesian approach ranged from 0.7% to 100% with the median (IQR) of 42% (17%-84%), and did not vary significantly between herd size classes (p = 0.393) or geographical regions of Poland (p = 0.570). Concluding, SRLV infection is widespread in the Polish goat population, the north-western region of Poland is most extensively infected, and herds counting > 50 adult goats are more often infected.

Diseases associated with feline leukemia virus and feline immunodeficiency virus infection: A retrospective study of 1470 necropsied cats (2010-2020).

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses affecting cats worldwide, and the prevalence of infection varies considerably according to the geographic area. We retrospectively described FIV- and FeLV-associated diseases in a population of 1470 necropsied cats, of which 396 (26.9%) were infected with FeLV, 199 (13.5%) with FIV, and 134 (9.1%) with FeLV and FIV concomitantly. Cats infected with FeLV (OR 3.4) and co-infected with FeLV and FIV (OR 1.9) were more likely to have neoplasms. The diagnosis of lymphoma and leukemia was higher in cats infected with FeLV (OR 3.9 and 19.4, respectively) and coinfected with FeLV and FIV (OR 1.9 and 19.3, respectively). The odds of diagnosing bacterial diseases were higher in cats coinfected with FeLV and FIV (OR: 2.8), whereas the odds of viral diseases were higher in those infected with FeLV (OR: 2.8), with 2.2 times more diagnoses of feline infectious peritonitis. Neoplastic and infectious diseases in FIV-infected cats did not differ significantly from those in uninfected cats. According to our results, a high prevalence of retroviral infections was observed in southern Brazil, mainly in relation to FeLV. Infected cats were significantly younger than uninfected cats. The main causes of death associated with FeLV infection and FeLV and FIV coinfection were neoplastic and infectious diseases. In contrast, FIV infection was not associated with any specific condition.

Associations between small ruminant lentivirus infection and total milk yield and somatic cell count in a dairy sheep flock.

BACKGROUND: Small ruminant lentiviruses (SRLVs) are lentiviruses of sheep and goats, formerly known as maedi-visna (MV) in sheep and caprine encephalitis and arthritis in goats. In sheep, SRLVs commonly cause progressive pneumonia, wasting and indurative mastitis. SRLVs have a long latent period, and chronic production losses are often not recognised until very late. Few studies quantifying the production losses in ewes have been published, and none have been published under UK flock husbandry conditions. METHODS: Production records of milk yield and somatic cell count (SCC) from a dairy flock of 319 milking East Friesian × Lacaune ewes identified as MV infected via routine serological screening for SRLV antibodies were used in multivariable linear regression modelling to estimate the impact of SRLV status on total milk yield and SCC. RESULTS: Milk yield was reduced in seropositive ewes by 8.1%-9.2% over an entire lactation. SCC counts were not significantly different in SRLV-infected and unifected animals. LIMITATIONS: Further parameters, such as body condition score or clinical mastitis, that were not available may have clarified the underlying cause of milk yield drop. CONCLUSIONS: The study demonstrates substantial production losses in an SRLV-affected flock and highlights the impact of the virus on a farm's economic viability.

Serological testing of an equal-volume milk sample - a new method to estimate the seroprevalence of small ruminant lentivirus infection?

BACKGROUND: In cattle attempts to evaluate within-herd prevalence of various infectious and parasitic diseases by bulk-tank milk (BTM) testing with ELISA have been made with moderate success. The fact that BTM is composed of variable and unknown volumes of milk from individual lactating animals weakens the relationship between numerical result of the ELISA and the within-herd prevalence. We carried out a laboratory experimental study to evaluate if a pooled milk sample created by mixing an equal volume of individual milk samples from seropositive and seronegative goats, henceforth referred to as an equal-volume milk sample (EVMS), would allow for accurate estimation of within-herd seroprevalence of caprine arthritis-encephalitis (CAE) using 3 different commercial ELISAs. By mixing randomly selected milk samples from seronegative and seropositive goats, 193 EVMS were created - 93 made of seronegative samples and 100 with the proportion of seropositive individual milk samples (EVMS%POS) ranging from 1 to 100%. EVMS%POS could be considered as a proxy for the within-herd seroprevalence. Then, OD of EVMS (ODEVMS) of the 193 EVMS was measured using 3 commercial ELISAs for CAE - 2 indirect and 1 competitive. RESULTS: The cut-off values of ODEVMS indicating SRLV infection were determined. The regression functions were developed to link ODEVMS with EVMS%POS. A significant monotonic relationship between ODEVMS measured with 2 commercial indirect ELISAs and EVMS%POS was identified. Two regression models developed on this basis described approximately 90% of variability and allowed to estimate EVMS%POS, when it was below 50%. High ODEVMS indicated EVMS%POS of > 50%. CONCLUSION: Our study introduces the concept of serological testing of EVMS as a method of detecting SRLV-infected herds and estimating the proportion of strongly seropositive goats. Further field studies are warranted to assess practical benefits of EVMS serological testing.

Factors associated with small ruminant lentivirus infection in goat herds from Pernambuco state, Northeast region of Brazil.

Serum samples (n = 1532) were collected between May 2011 to April 2012 from goats from 76 herds (49 from dairy farms and 27 herds for genetic improvement) from three geographical regions from the state of Pernambuco, Brazil: Zona da Mata, Agreste, and Sertão. Samples were processed using agar gel immunodiffusion test, with p28 CAEV antigen. The objective was to determine the risk factors for small ruminant lentivirus (SRLV) in dairy goats and goats with high genetic value. Overall, seroprevalence was 13.7% (210/1532) [95% CI: 12-15.4%] in animals and 67.1% (51/76) [95% CI: 56.5%- 77.7%] in herds. In dairy farms the seroprevalence was 73.5% (36/49) [95% CI: 61.1%- 85.8%], and in properties with animals of high genetic value it was 55.6% (15/27) [95% CI: 36.8%- 74.3%]. Robust Poisson regression analysis adjusted by the random effect of the herd showed that risk factors were: importing bucks from another Brazilian state (prevalence ratio [PR] = 4.73 [95% CI: 2.05; 10.88]), not isolating sick animals (PR = 3.27 [95% CI: 2.24; 4.76]), and participating in fairs/animal crowding (PR = 1.52 [95% CI: 1.09; 2.11]). Prevalence results show that SRLV is present in caprine herds in the state of Pernambuco and identified risk factors are strongly related to animal transit. Considering the epidemiological situation, the first step for mitigating the consequences of this disease would be controlling animal transit.

Small ruminant lentivirus capsid protein (SRLV-p25) antigenic structural prediction and immunogenicity to recombinant SRLV-rp25-coupled to immunostimulatory complexes based on glycyrrhizinic acid.

Small ruminant lentiviruses (SRLV) infect sheep and goats resulting in significant economic losses. This study evaluated for the first time the predicted conformational structure of the SRLV-capsid-protein 25 (SRLV-p25) and analyzed the antigenicity of recombinant protein (SRLV-rp25) in mice by coupling to an immunostimulatory complexes based on glycyrrhizinic acid liposomes (GAL) and tested plasma from goats and sheep naturally infected. Analysis in silico and conformational structure of SRLV-p25 (genotype B-FESC-752) showed similar characteristics to other lentiviral capsids. The efficient expression of SRLV-rp25 was confirmed by Western blot. The humoral immune responses in mice showed an increased level of antibodies from day 21 to 35 of the SRLV-rp25-GAL and SRLV-rp25-ISCOM® groups and the cellular immune response showed no significant difference in IL-10 levels (P >.05), however, a significant difference (P <.001) was observed when comparing SRLV-rp25-GAL with SRLV-rp25 groups. Immunoreactivity toward SRLV-rp25 revealed 61% of positive samples from naturally infected goats and sheep.

Clinicopathological and Epidemiological Findings in Pet Cats Naturally Infected with Feline Immunodeficiency Virus (FIV) in Australia.

Feline immunodeficiency virus (FIV) infection in experimentally infected domestic cats produces characteristic clinical manifestations including hematological changes, neurological disease, neoplasia (most notably lymphoma) and lymphopenia-mediated immunodeficiency predisposing cats to a range of secondary infections. Conflicting reports exist, however, with regard to disease associations and survival time in naturally FIV-infected cats. The purpose of this retrospective case−control study was to investigate the effect of natural FIV infection on hematological, blood biochemical and urinalysis parameters and survival time in three cohorts of pet cats in Australia. Cohorts 1 and 2 were recruited from a large veterinary hospital in Melbourne, Victoria (n = 525 and 282), while a third cohort consisted of cats recruited from around Australia as part of a FIV field vaccine efficacy trial (n = 425). FIV-infected cats in cohorts 1, 2 and 3 were found to have 15/37 (41%), 13/39 (33%) and 2/13 (15%) clinicopathological parameters significantly different to FIV-uninfected cats, respectively. Two changes in FIV-infected cats in cohort 1, hypochromia (low hemoglobin) and hyperglobulinemia, were outside the supplied reference intervals and should serve as diagnostic triggers for FIV testing. Kaplan−Meier survival analysis of cats in cohorts 1 and 2 combined did not find any difference between FIV-infected and FIV-uninfected cats, however a confounding factor was a large euthanasia rate within the first 12 months in both groups. Three significant (p < 0.05) spatial clusters of FIV infection were identified in Melbourne. A possible relationship between FIV infection status and socioeconomic disadvantage was discovered, based on three government indices of socioeconomic status (p < 0.001). Until longitudinal field studies are performed in Australia to further investigate the long-term effects of natural FIV infection, Australian veterinarians should consider FIV to be an important infection of pet cats, and recommend measures to prevent FIV infection.

System-wide identification of myeloid markers of TB disease and HIV-induced reactivation in the macaque model of Mtb infection and Mtb/SIV co-infection.

Mycobacterium tuberculosis (Mtb) has developed specialized mechanisms to parasitize its host cell, the macrophage. These mechanisms allow it to overcome killing by oxidative burst and persist in the wake of an inflammatory response. Mtb infection in the majority of those exposed is controlled in an asymptomatic form referred to as latent tuberculosis infection (LTBI). HIV is a well-known catalyst of reactivation of LTBI to active TB infection (ATB). Through the use of nonhuman primates (NHPs) co-infected with Mtb and Simian Immunodeficiency Virus (Mtb/SIV), we are able to simulate human progression of TB/AIDS comorbidity. The advantage of NHP models is that they recapitulate the breadth of human TB outcomes, including immune control of infection, and loss of this control due to SIV co-infection. Identifying correlates of immune control of infection is important for both vaccine and therapeutics development. Using macaques infected with Mtb or Mtb/SIV and with different clinical outcomes we attempted to identify signatures between those that progress to active infection after SIV challenge (reactivators) and those that control the infection (non-reactivators). We particularly focused on pathways relevant to myeloid origin cells such as macrophages, as these innate immunocytes have an important contribution to the initial control or the lack thereof, following Mtb infection. Using bacterial burden, C-reactive protein (CRP), and other clinical indicators of disease severity as a guide, we were able to establish gene signatures of host disease state and progression. In addition to gene signatures, clustering algorithms were used to differentiate between host disease states and identify relationships between genes. This allowed us to identify clusters of genes which exhibited differential expression profiles between the three groups of macaques: ATB, LTBI and Mtb/SIV. The gene signatures were associated with pathways relevant to apoptosis, ATP production, phagocytosis, cell migration, and Type I interferon (IFN), which are related to macrophage function. Our results suggest novel macrophage functions that may play roles in the control of Mtb infection with and without co-infection with SIV. These results particularly point towards an interplay between Type I IFN signaling and IFN-γ signaling, and the resulting impact on lung macrophages as an important determinant of progression to TB.

Susceptibility of different TMEM154 genotypes in three Italian sheep breeds infected by different SRLV genotypes.

Small ruminant lentiviruses (SRLV) belong to the Retroviridae family and can cause various diseases. One of the most impacting diseases is visna-maedi, a complex disease characterized by long latencies and chronic progressive inflammatory events affecting the nervous system, lungs, mammary gland, and articular joints. A single nucleotide polymorphism (rs408593969, c.103G>A, missense mutation E35K) in the ovine transmembrane protein gene 154 (TMEM154) was identified as protective against small ruminant lentivirus infection in different herds worldwide. However, there is evidence in the scientific literature of a breed-specificity of this protective effect and, furthermore, there are still limited studies regarding the association between the animal genotype and the infecting virus genotype. Thus, the aim of this study was to further investigate the association between the animal genotype for the suggested protective mutation and the infecting virus genotype, in three different sheep breeds reared in northern Italy. The results obtained only partially confirmed the data available in the literature, as the protective effect was confirmed only for SRLV genotype A clusters, while other genotypes (namely B and E) infected AA and GA animals. Further studies with an experimental infection of specific virus genotypes in hosts with specific genotypes are required to confirm the larger number of cases the results obtained in this study.

Evidence of bovine immunodeficiency virus: A molecular survey in water buffalo populations of Iran.

BACKGROUND: Bovine immunodeficiency virus (BIV) is a member of the Retroviridae family causing a progressive lifelong infection in cattle and buffaloes. OBJECTIVE: Despite the worldwide distribution of the virus, the studies concerning the prevalence of BIV in buffalo populations have not been conducted in Iran as yet. METHODS: The BIV proviral DNA was surveyed in 120 whole blood samples of water buffaloes in southwestern Iran. Nested PCR was employed to amplify a 298-bp fragment of the pol gene. The BIV Pol sequence was detected in 9.1% of the samples. Among PCR-positive samples, two amplified fragments were confirmed by nucleotide sequencing. RESULTS AND CONCLUSIONS: The studied sequences were completely identical to each other and had more than 98%-99% nucleotide homology to R-29 and HXB3 sequences previously deposited in GenBank. Some point mutations that caused coding substitutions were observed in the studied isolates, compared to other strains. A phylogenetic tree was generated based on the BIV Pol nucleotide sequences reported from other countries. All the BIV strains originated from a unique main cluster and then separated from each other over time. This is the first report on the molecular detection of BIV infections in water buffalo populations in Iran. The wide distribution of BIV in different countries including Iran indicates the importance of the infection as it relates to animal health. Although buffaloes show greater resistance to diseases, they should be considered a health risk to cattle. Furthermore, BIV has negative effects on buffalo milk production and can predispose them to secondary infections. Hence, the findings of this study can advance our understanding of the occurrence of BIV infection in Iran, which can play an important role in the distribution of the disease worldwide.

Genetic and antigenic characterization of Brazilian SRLV strains: Natural small ruminant interspecies transmission from mixed herds.

Cross-species transmission events and mixed infection of small ruminant lentiviruses (SRLVs) were studied in seven goats and two sheep from three small ruminant mixed flocks from Northeast and Southeast Brazil. Genetic and antigenic analyses with gag/env genes and ELISA multiepitope SU1/SU5 recombinant antigens were carried out, respectively. The genetic analysis of gag and env sequences showed high viral diversity in both species, MVV-like (subtype A1) and CAEV-like B1 in goats, and CAEV-like (subtype B1) in sheep, revealing SRLV interspecies transmission from sheep to goats and vice versa in Brazilian farms. Two Brazilian caprine lentiviruses were segregated in two new genetic clades based on gag analyses, which suggests a new classification into heterogenic genotype A. Furthermore, goat isolates were grouped into subtype A1 and B1 clusters. Cross-reactive antibodies were detected in goats using ELISA with a recombinant antigen carrying SU1 and SU5 immunodominant epitopes; the results showed anti-CAEV and MVV antibodies in goats and anti-CAEV antibodies in sheep. This result can be associated with the high divergence in the V4 region due to SRLV variability. All results confirm cross-species infection of SRLV in Brazilian mixed herds.

Age-related cognitive impairments in domestic cats naturally infected with feline immunodeficiency virus.

BACKGROUND: Age-related dementia has been documented in domestic cats; however, its interaction with naturally occurring feline immunodeficiency virus (FIV) infection has been investigated minimally. METHODS: Visuospatial working memory (VSWM) and problem-solving (PS) ability were evaluated in FIV-infected (n = 37) and control cats (n = 39) using two cognitive tasks tested serially, which assessed the ability of cats to remember the location of a baited container after a set delay, then evaluated the capability of the cats to manipulate the container to obtain the food within a time limit. Cats were categorized using 7 years of age as a cut-off to determine age-related differences. The relationship between cognitive performance and FIV viral load was investigated using real-time PCR cycle threshold (Ct ) values. RESULTS: Age significantly affected VSWM and PS ability. Younger cats had better VSWM performance and PS ability compared to older cats with the same FIV status. There was no difference between younger FIV-positive and negative cats in either part of the task. While older FIV-positive cats had significantly worse VSWM than older FIV-negative cats, no differences were found in PS ability. Additionally, Ct values predicted VSWM but not PS ability. CONCLUSION: Age-related cognitive impairments and FIV infection appear synergetic, causing greater cognitive deficits in older FIV-infected cats.

Genetic Characterization of Small Ruminant Lentiviruses (SRLVs) Circulating in Naturally Infected Sheep in Central Italy.

Small ruminant lentiviruses (SRLVs) represent a very heterogeneous group of ss-RNA viruses that infect sheep and goats worldwide. They cause important, deleterious effects on animal production and limit the animal trade. SRLVs show a high genetic variability due to high mutation rate and frequent recombination events. Indeed, five genotypes (A-E) and several subtypes have been detected. The aim of this work was to genetically characterize SRLVs circulating in central Italy. On this basis, a phylogenetic study on the gag-pol genetic region of 133 sheep, collected from 19 naturally infected flocks, was conducted. In addition, to evaluate the frequency of mutation and the selective pressure on this region, a WebLogo 3 analysis was performed, and the dN/dS ratio was computed. The results showed that 26 samples out of 133 were clustered in genotype A and 106 samples belonged to genotype B, as follows: A9 (n = 8), A11 (n = 10), A24 (n = 7), B1 (n = 2), B2 (n = 59), and B3 (n = 45). No recombination events were found. Mutations were localized mainly in the VR-2 region, and the dN/dS ratio of 0.028 indicated the existence of purifying selection. Since the genetic diversity of SRLVs could make serological identification difficult, it is important to perform molecular characterization to ensure a more reliable diagnosis, to maintain flock health status, and for the application of local and national control programs.

Molecular Characterization of Small Ruminant Lentiviruses Isolated from Polish Goats with Arthritis.

Previous studies revealed that the small ruminant lentivirus (SRLV) population in Poland is highly heterogeneous. All SRLVs detected from Polish sheep and goats so far have belonged to subtypes B1, B2, A1, A5, A12, A13, A16, A17, A18, A23 and A24. However, all characterized strains originated from asymptomatic animals. This is the first study that characterizes the molecular properties of SRLVs isolated from different organs of six arthritic goats. Segments from three genomic regions (gag, LTR and env) were analyzed. In addition, we quantified the SRLV proviral load in the blood and different organs and examined its association with different degrees of histopathological lesions. All sequences obtained from the goats involved in this study were homogeneous, showing an average degree of variability of 4.8%, 3.7% and 8.8% for gag, LTR and env, respectively. Phylogenetic analysis revealed that the sequences from the analyzed goats were clustered within SRLVs group A and formed a new subtype within this group, tentatively named A27. The histopathological examination of the lung, mammary gland, synovial membranes of joints and brain of the analyzed goats revealed evidence of inflammatory processes associated with SRLV infection, which was confirmed by positive immunohistochemistry assays. No significant correlation was observed between histological features and alterations in the sequences from different tissues. No tissue-specific signature pattern was identified. It was shown that animals with a higher proviral load showed more lesion severity in various SRLV-affected tissues, indicating a positive association between these two parameters. Our results also revealed differences in the SRLV load between animals even though the sequences derived from all of the goats were closely related, suggesting that host factors may restrict and control viral replication. This study provides new information about SRLV variants isolated from arthritic goats; however, more studies, including the isolation and characterization of biological properties of these viruses, should be performed to evaluate their pathogenic potential.